Hart, S., Schreiber, S. & Levine, J. (preprint), "Intraspecific variation and species coexistence"

BibTeX:
@article{, author = {S.P. Hart and S.J. Schreiber and J.M. Levine}, title = {Intraspecific variation and species coexistence}, year = {preprint} } 
Schreiber, S., Ruian, K., Loverdo, C., Park, M., Ahsan, P. & LloydSmith, J. (in review), "Cross scale dynamics and the evolutionary emergence of infectious diseases"

BibTeX:
@article{, author = {Schreiber, S.J. and Ruian, K. and Loverdo, C. and Park, M. and Ahsan, P. and LloydSmith, J.O.}, title = {Cross scale dynamics and the evolutionary emergence of infectious diseases}, year = {in review} } 
Schreiber, S. & Ross, N. (in review), "Individualbased Integral Projection Models: The role of sizestructure on extinction risk and establishment success"

BibTeX:
@article{, author = {S.J. Schreiber and N. Ross}, title = {Individualbased Integral Projection Models: The role of sizestructure on extinction risk and establishment success}, year = {in review}, url = {http://biorxiv.org/content/early/2015/10/15/029165} } 
Moore, J., Lipcius, R.N., Puckett, B. & Schreiber, S. (in review), "The demographic consequences of getting older and bigger in oyster populations"

BibTeX:
@article{, author = {J.L. Moore and R. N. Lipcius and B. Puckett and S.J. Schreiber}, title = {The demographic consequences of getting older and bigger in oyster populations}, year = {in review} } 
Patel, S. & Schreiber, S. (in press), "Evolutionary driven regime shifts in ecological systems with intraguild predation", American Naturalist.

BibTeX:
@article{amnat15c, author = {S Patel and S.J. Schreiber}, title = {Evolutionary driven regime shifts in ecological systems with intraguild predation}, journal = {American Naturalist}, year = {in press}, url = {http://www.jstor.org/stable/10.1086/683170} } 
Schreiber, S. (in press), "Unifying within and betweengeneration bethedging theories: An ode to J.H Gillespie", American Naturalist.

BibTeX:
@article{amnat15d, author = {S.J. Schreiber}, title = {Unifying within and betweengeneration bethedging theories: An ode to J.H Gillespie}, journal = {American Naturalist}, year = {in press} } 
Rosenheim, J., Williams, N., Schreiber, S. & Rapp, J. (in press), "Modest pollen limitation of wholeplant seed production is in good agreement with modest uncertainty in wholeplant pollen receipt", American Naturalist.

BibTeX:
@article{amnat15e, author = {J.A. Rosenheim and N.W. Williams and S.J. Schreiber and J. Rapp}, title = {Modest pollen limitation of wholeplant seed production is in good agreement with modest uncertainty in wholeplant pollen receipt}, journal = {American Naturalist}, year = {in press} } 
Schreiber, S. & Patel, S. (in press), "Evolutionarily induced alternative states and coexistence in systems with apparent competition", Natural Resource Modelling.

BibTeX:
@article{nrm15, author = {Schreiber, S.J. and Patel, S}, title = {Evolutionarily induced alternative states and coexistence in systems with apparent competition}, journal = {Natural Resource Modelling}, year = {in press} } 
Rosenheim, J., Schreiber, S. & Williams, N. (in press), "Does an oversupply of ovules cause pollen limitation?", The New Phytologist.

BibTeX:
@article{, author = {Rosenheim, J.A., and Schreiber, S.J. and Williams, N.W.}, title = {Does an oversupply of ovules cause pollen limitation?}, journal = {The New Phytologist}, year = {in press} } 
Schreiber, S., Rosenheim, J., Williams, N. & Harder, L. (2015), "Evolutionary and Ecological Consequences of Multiscale Variation in Pollen Receipt for Seed Production", American Naturalist. Vol. 185, pp. 1429.

BibTeX:
@article{amnat15a, author = {S.J. Schreiber and J.A. Rosenheim and N.W. Williams and L. Harder}, title = {Evolutionary and Ecological Consequences of Multiscale Variation in Pollen Receipt for Seed Production}, journal = {American Naturalist}, year = {2015}, volume = {185}, pages = {1429} } 
Reigeda, C., Schreiber, S., Altermatt, F. & Holyoak, M. (2015), "Metapopulation dynamics on ephemeral patches", American Naturalist. Vol. 185, pp. 183195.

BibTeX:
@article{amnat15b, author = {C. Reigeda and S.J. Schreiber and F. Altermatt and M. Holyoak}, title = {Metapopulation dynamics on ephemeral patches}, journal = {American Naturalist}, year = {2015}, volume = {185}, pages = {183195} } 
Gaylord, B., Kroeker, K., Sunday, J., Anderson, K., Barry, J., Brown, N., Connell, S., Dupont, S., Fabricius, K., HallSpencer, J., Klinger, T., Milazzo, M., Munday, P., Russell, B., Sanford, E., Schreiber, S., Thiyagarahan, V., Vaughan, M., Widdicombe, S. & Harley, C. (2015), "Ocean acidification through the lens of ecological theory", Ecology. Vol. 96, pp. 315.

BibTeX:
@article{ecology15, author = {B Gaylord and K Kroeker and J Sunday and K Anderson and J Barry and N Brown and S Connell and S Dupont and K Fabricius and J HallSpencer and T Klinger and M Milazzo and P Munday and B Russell and E Sanford and S Schreiber and V Thiyagarahan and M Vaughan and S Widdicombe and C Harley}, title = {Ocean acidification through the lens of ecological theory}, journal = {Ecology}, year = {2015}, volume = {96}, pages = {315} } 
Lipcius, R., Burke, R., McCulloch, D., Schreiber, S., Schulte, D., Seitz, R. & Shen, J. (2015), "Overcoming restoration paradigms: value of the historical record and metapopulation dynamics in native oyster restoration", Frontiers in Marine Science. Vol. 2, pp. Article 65 (115).

Abstract: Restoration strategies for native oyster populations rely on multiple sources of information, which often conflict due to time and spacevarying patterns in abundance and distribution. For instance, strategies based on population connectivity and disease resistance can differ, and extant and historical records of abundance and distribution are often at odds, such that the optimal strategy is unclear and valuable restoration sites may be excluded from consideration. This was the case for the Lynnhaven River subestuary of lower Chesapeake Bay, which was deemed unsuitable for Eastern Oyster restoration based on physical conditions, disease challenge, and extant oyster abundance. Consequently, we (i) evaluated previously unknown historical data from the 1800s, (ii) quantified extant oyster recruitment and abundance, physical conditions, and disease presence on constructed restoration reefs and alternative substrates, and (iii) assessed simulations from biophysical models to identify potential restoration sites in the metapopulation. The collective data distinguished numerous restoration sites (i) in the polyhaline zone (salinity 18.422.2) where disease resistance is evolving, (ii) where oysters were abundant in the late 1800searly 1900s, (iii) of recent high recruitment, abundance and survival, despite consistent and elevated disease challenge, and (iv) interconnected as a metapopulation via larval dispersal. Moreover, a network of constructed restoration reefs met size structure, abundance and biomass standards of restoration success. These findings demonstrate that assumptions about the suitability of sites for oyster restoration based on individual processes can be severely flawed, and that indepth examination of multiple processes and sources of information are required for oyster reef restoration plans to maximize success. We use these findings and previous information to recommend a strategy for successful restoration of subtidal oyster reefs throughout the range of the Eastern Oyster. 
BibTeX:
@article{fms15, author = {Lipcius, R.N. and Burke, R.P. and McCulloch, D.N. and Schreiber, S.J. and Schulte, D.M. and Seitz, R.D. and Shen, J.}, title = {Overcoming restoration paradigms: value of the historical record and metapopulation dynamics in native oyster restoration}, journal = {Frontiers in Marine Science}, year = {2015}, volume = {2}, pages = {Article 65 (115)}, url = {http://journal.frontiersin.org/article/10.3389/fmars.2015.00065/abstract} } 
Evans, S., Hening, A. & Schreiber, S. (2015), "Protected polymorphisms and evolutionary stability of patchselection strategies in stochastic environments", Journal of Mathematical Biology. Vol. 71, pp. 325359.

BibTeX:
@article{jmb15, author = {S Evans and A Hening and S.J. Schreiber}, title = {Protected polymorphisms and evolutionary stability of patchselection strategies in stochastic environments}, journal = {Journal of Mathematical Biology}, year = {2015}, volume = {71}, pages = {325359} } 
Faure, M. & Schreiber, S.J. (2015), "Convergence of evolutionary urn processes to nonequilibrium attractors", Stochastic Processes and their Applications. Vol. 125, pp. 30533074.

BibTeX:
@article{spa15, author = {M. Faure and S. J. Schreiber}, title = {Convergence of evolutionary urn processes to nonequilibrium attractors}, journal = {Stochastic Processes and their Applications}, year = {2015}, volume = {125}, pages = {30533074} } 
Faure, M. & Schreiber, S.J. (2014), "Quasistationary distributions for randomly perturbed dynamical systems", Annals of Applied Probability. Vol. 24, pp. 553598.

BibTeX:
@article{aap14, author = {M. Faure and S. J. Schreiber}, title = {Quasistationary distributions for randomly perturbed dynamical systems}, journal = {Annals of Applied Probability}, year = {2014}, volume = {24}, pages = {553598} } 
Rosenheim, J., Williams, N. & Schreiber, S. (2014), "Parental optimism versus parental pessimism in plants: how common should we expect pollen limitation to be", American Naturalist. Vol. 184, pp. 7590.

BibTeX:
@article{amnat14, author = {J.A. Rosenheim and N.W. Williams and S.J. Schreiber}, title = {Parental optimism versus parental pessimism in plants: how common should we expect pollen limitation to be}, journal = {American Naturalist}, year = {2014}, volume = {184}, pages = {7590} } 
Schreiber, S., Smith, K. & Getz, W. (2014), "Calculus for the Life Sciences" , pp. 710. John Wiley & Sons.

BibTeX:
@book{calculusbook14, author = {S Schreiber and K Smith and W Getz}, title = {Calculus for the Life Sciences}, publisher = {John Wiley & Sons}, year = {2014}, pages = {710}, url = {http://www.wiley.com/WileyCDA/WileyTitle/productCdEHEP002970.html} } 
Roth, G. & Schreiber, S. (2014), "Pushed to brink: Allee effects, environmental stochasticity, and extinction", Special Issue on Allee Effects for", Journal of Biological Dynamics. Vol. 8, pp. 187205.

BibTeX:
@article{jbd14, author = {G Roth and S.J. Schreiber}, title = {Pushed to brink: Allee effects, environmental stochasticity, and extinction", Special Issue on Allee Effects for}, journal = {Journal of Biological Dynamics}, year = {2014}, volume = {8}, pages = {187205} } 
Roth, G. & Schreiber, S. (2014), "Persistence in fluctuating environments for interacting structured populations", Journal of Mathematical Biology. Vol. 68, pp. 12671317.

BibTeX:
@article{jmb14, author = {G. Roth and S.J. Schreiber}, title = {Persistence in fluctuating environments for interacting structured populations}, journal = {Journal of Mathematical Biology}, year = {2014}, volume = {68}, pages = {12671317} } 
Evans, S.N., Ralph, P., Schreiber, S.J. & Sen, A. (2013), "Stochastic growth rates in spatiotemporal heterogeneous environments", Journal of Mathematical Biology. Vol. 66, pp. 423476.

BibTeX:
@article{jmb13, author = {S. N. Evans and P. Ralph and S. J. Schreiber and A. Sen}, title = {Stochastic growth rates in spatiotemporal heterogeneous environments}, journal = {Journal of Mathematical Biology}, year = {2013}, volume = {66}, pages = {423476} } 
Schreiber, S. (2013), "Undergraduate Mathematics for the Life Sciences Processes and Models Assessment and Directions" , pp. 177188. Mathematical Association of America.

BibTeX:
@inbook{Processes2013, author = {Schreiber, S..J.}, title = {Undergraduate Mathematics for the Life Sciences Processes and Models Assessment and Directions}, publisher = {Mathematical Association of America}, year = {2013}, pages = {177188} } 
Park, M., Loverdo, C., Schreiber, S. & LloydSmith, J. (2013), "Multiple scales of selection influence the evolutionary emergence of novel pathogens", Philiosophical Transactions of the Royal Soceity. B. Vol. Vol., pp. 368.

BibTeX:
@article{ptrb13, author = {M. Park and C. Loverdo and S.J. Schreiber and J.O. LloydSmith}, title = {Multiple scales of selection influence the evolutionary emergence of novel pathogens}, journal = {Philiosophical Transactions of the Royal Soceity. B}, year = {2013}, volume = {Vol.}, pages = {368} } 
Schreiber, S. & Killingback, T. (2013), "Cycling in space: Persistence of rockpaperscissor metacommunities", Theoretical Population Biology. Vol. 86, pp. 111.

BibTeX:
@article{tpb13, author = {S.J. Schreiber and T.P. Killingback}, title = {Cycling in space: Persistence of rockpaperscissor metacommunities}, journal = {Theoretical Population Biology}, year = {2013}, volume = {86}, pages = {111} } 
Schreiber, S. (2012), "Evolution of patch selection in stochastic environments", American Naturalist. Vol. 180, pp. 1734.

BibTeX:
@article{amnat12, author = {S.J. Schreiber}, title = {Evolution of patch selection in stochastic environments}, journal = {American Naturalist}, year = {2012}, volume = {180}, pages = {1734} } 
Loverdo, C., Park, M., Schreiber, S. & LloydSmtih, J. (2012), "Influence of viral replication mechanisms on withinhost evolutionary dynamics", Evolution. Vol. 66, pp. 34623471.

BibTeX:
@article{evolution12, author = {C. Loverdo and M. Park and S.J. Schreiber and J. LloydSmtih}, title = {Influence of viral replication mechanisms on withinhost evolutionary dynamics}, journal = {Evolution}, year = {2012}, volume = {66}, pages = {34623471} } 
Schreiber, S.J. (2012), "Persistence for stochastic difference equations: a minireview", Journal of Difference Equations and Applications. Vol. 18, pp. 13811403. Taylor & Francis.

BibTeX:
@article{jdea11, author = {Schreiber, S. J.}, title = {Persistence for stochastic difference equations: a minireview}, journal = {Journal of Difference Equations and Applications}, publisher = {Taylor & Francis}, year = {2012}, volume = {18}, pages = {13811403} } 
Schaiber, J., Silverstein, R., Kaczmarczyk, A., Rutaganira, R., Aggarwal, T., Schwemmer, M., Hom, C., Grossberg, R. & Schreiber, S. (2012), "Constraints on the use of lifespan shortening Wolbachia to control dengue fever", Journal of Theoretical Biology. Vol. 297, pp. 2632.

BibTeX:
@article{jtb12, author = {Schaiber, J.G. and Silverstein, R. and Kaczmarczyk, A.N. and Rutaganira, R.U. and Aggarwal, T. and Schwemmer, M. and Hom, C.L. and Grossberg, R.K. and Schreiber, S.J.}, title = {Constraints on the use of lifespan shortening Wolbachia to control dengue fever}, journal = {Journal of Theoretical Biology}, year = {2012}, volume = {297}, pages = {2632} } 
Ellner, S. & Schreiber, S. (2012), "Temporally variable dispersal and demography can accelerate the spread of invading species", Theoretical Population Biology. Vol. 82, pp. 283298.

BibTeX:
@article{tpb12, author = {S.P. Ellner and S.J. Schreiber}, title = {Temporally variable dispersal and demography can accelerate the spread of invading species}, journal = {Theoretical Population Biology}, year = {2012}, volume = {82}, pages = {283298} } 
Altermatt, F., Schreiber, S. & Holyoak, M. (2011), "Interactive effects of disturbance and directionality of dispersal on species richness and composition in metacommunities", Ecology. Vol. 92, pp. 859870.

BibTeX:
@article{ecology11a, author = {F Altermatt and S.J. Schreiber and M Holyoak}, title = {Interactive effects of disturbance and directionality of dispersal on species richness and composition in metacommunities}, journal = {Ecology}, year = {2011}, volume = {92}, pages = {859870} } 
Schreiber, S.J., Bolnick, D. & Bürger, R. (2011), "The community effects of phenotypic and genetic variation within a predator population", Ecology. Vol. 92, pp. 15821593.

BibTeX:
@article{ecology11b, author = {S. J. Schreiber and D. Bolnick and R. Bürger}, title = {The community effects of phenotypic and genetic variation within a predator population}, journal = {Ecology}, year = {2011}, volume = {92}, pages = {15821593} } 
Schreiber, S.J. & Li, C.K. (2011), "Evolution of unconditional dispersal in periodic environments", Journal of Biological Dynamics (special issue on Adaptive Dynamics). Vol. 5, pp. 120134.

BibTeX:
@article{jbd11, author = {S. J. Schreiber and C. K. Li}, title = {Evolution of unconditional dispersal in periodic environments}, journal = {Journal of Biological Dynamics (special issue on Adaptive Dynamics)}, year = {2011}, volume = {5}, pages = {120134} } 
Schreiber, S.J., Benaïm, M. & Atchadé, K.A.S. (2011), "Persistence in fluctuating environments", Journal of Mathematical Biology. Vol. 62, pp. 655683.

Abstract: Understanding under what conditions interacting populations, whether they be plants, animals, or viral particles, coexist is a question of theoretical and practical importance in population biology. Both biotic interactions and environmental fluctuations are key factors that can facilitate or disrupt coexistence. To better understand this interplay between these deterministic and stochastic forces, we develop a mathematical theory extending the nonlinear theory of permanence for deterministic systems to stochastic difference and differential equations. Our condition for coexistence requires that there is a fixed set of weights associated with the interacting populations and this weighted combination of populations' invasion rates is positive for any (ergodic) stationary distribution associated with a subcollection of populations. Here, an invasion rate corresponds to an average percapita growth rate along a stationary distribution. When this condition holds and there is sufficient noise in the system (i.e. all population states are accessible), we show that the populations approach a unique positive stationary distribution. Moreover, we show that our coexistence criterion is robust to small perturbations of the model functions. Using this theory, we illustrate that (i) environmental noise enhances or inhibits coexistence in communities with rockpaperscissor dynamics depending on correlations between interspecific demographic rates, (ii) stochastic variation in mortality rates has no effect on the coexistence criteria for discretetime LotkaVolterra communities, and (iii) random forcing can promote genetic diversity in the presence of exploitative interactions.!! 
BibTeX:
@article{jmb11, author = {S. J. Schreiber and M. Benaïm and K. A. S. Atchadé}, title = {Persistence in fluctuating environments}, journal = {Journal of Mathematical Biology}, year = {2011}, volume = {62}, pages = {655683} } 
Schreiber, S.J. & Ryan, M.E. (2011), "Invasion speeds of structured populations in fluctuating environments", Theoretical Ecology. Vol. 4, pp. 423434.

Abstract: We live in a time where climate models predict future increases in environmental variability and biological invasions are becoming increasingly frequent. A key to developing effective responses to biological invasions in increasingly variable environments will be estimates of their rates of spatial spread and the associated uncertainty of these estimates. Using stochastic, stagestructured, integrodifference equation models, we show analytically that invasion speeds are asymptotically normally distributed with a variance that decreases in time. We apply our methods to a simple juvenileadult model with stochastic variation in reproduction and an illustrative example with published data for the perennial herb, Calathea ovandensis. These examples buttressed by additional analysis reveal that increased variability in vital rates simultaneously slow down invasions yet generate greater uncertainty about rates of spatial spread. Moreover, while temporal autocorrelations in vital rates inflate variability in invasion speeds, the effect of these autocorrelations on the average invasion speed can be positive or negative depending on life history traits and how well vital rates ``remember'' the past.!! 
BibTeX:
@article{schreiberryan11, author = {S. J. Schreiber and M. E. Ryan}, title = {Invasion speeds of structured populations in fluctuating environments}, journal = {Theoretical Ecology}, year = {2011}, volume = {4}, pages = {423434}, doi = {http://dx.doi.org/10.1007/s1208001000985} } 
Schreiber, S. (2011), "Mathematical Dances with Wolves", Science. Vol. 334, pp. 12141215.

BibTeX:
@article{science11, author = {S.J. Schreiber}, title = {Mathematical Dances with Wolves}, journal = {Science}, year = {2011}, volume = {334}, pages = {12141215} } 
Schreiber, S. (2011), "Sourcebook in Theoretical Ecology" California University of California Press.

BibTeX:
@inbook{sourcebook11, author = {Schreiber, S.J.}, title = {Sourcebook in Theoretical Ecology}, publisher = {California University of California Press}, year = {2011} } 
Bolnick, D., Amarasekare, P., Araújo, M.S., Bürger, R., Levine, J., Novak, M., Rudolf, V., Schreiber, S., Urban, M. & Vasseur, D. (2011), "Why intraspecific trait variation matters in community ecology", Trends in Ecology and Evolution. Vol. 26, pp. 185194.

BibTeX:
@article{TREE11, author = {D. Bolnick and P. Amarasekare and M. S. Araújo and R. Bürger and J. Levine and M. Novak and V.H. Rudolf and S.J. Schreiber and M. Urban and D. Vasseur}, title = {Why intraspecific trait variation matters in community ecology}, journal = {Trends in Ecology and Evolution}, year = {2011}, volume = {26}, pages = {185194} } 
Hofbauer, J. & Schreiber, S.J. (2010), "Robust permanence for interacting structured populations", Journal of Differential Equations. Vol. 248, pp. 19551971.

Abstract: The dynamics of interacting structured populations can be modeled by $dx_idt= A_i (x)x_i$ where $x_iin n_i$, $x=(x_1,x_k)$, and $A_i(x)$ are matrices with nonnegative offdiagonal entries. These models are permanent if there exists a positive global attractor and are robustly permanent if they remain permanent following perturbations of $A_i(x)$. Necessary and sufficient conditions for robust permanence are derived using dominant Lyapunov exponents $i($ of the $A_i(x)$ with respect to invariant measures $. The necessary condition requires $i i(>0$ for all ergodic measures with support in the boundary of the nonnegative cone. The sufficient condition requires that the boundary admits a Morse decomposition such that $i i(>0$ for all invariant measures $ supported by a component of the Morse decomposition. When the Morse components are Axiom A, uniquely ergodic, or support all but one population, the necessary and sufficient conditions are equivalent. Applications to spatial ecology, epidemiology, and gene networks are given. 
BibTeX:
@article{jde10, author = {J. Hofbauer and S. J. Schreiber}, title = {Robust permanence for interacting structured populations}, journal = {Journal of Differential Equations}, year = {2010}, volume = {248}, pages = {19551971} } 
Edwards, K.F. & Schreiber, S.J. (2010), "Preemption of space can lead to intransitive coexistence of competitors", Oikos. Vol. 119, pp. 12011209.

Abstract: Intransitive competition has the potential to be a powerful contributor to species coexistence, but there are few proposed biological mechanisms that could create intransitivities in natural communities. Using a threespecies model of competition for space, we demonstrate a mechanism for coexistence that combines a colonizationcompetition tradeoff between two species with the ability of a third species to preempt space from the other competitors. The combination of differential abilities to colonize, preempt, and overtake space creates a community where no single species can exclude both of its competitors. The dynamics of this kind of community are analogous to rockpaperscissors competition, and the threespecies community can persist even though not all pairs of species can coexist in isolation. In distinction to prior results, this is a mechanism of intransitivity that does not require nonhierarchical local interference competition. We present parameter estimates from a subtidal marine community illustrating how documented competitive traits can lead to preemptionbased intransitivities in natural communities, and we describe methods for an empirical test of the occurrence of this mechanism. 
BibTeX:
@article{oikos10, author = {K. F. Edwards and S. J. Schreiber}, title = {Preemption of space can lead to intransitive coexistence of competitors}, journal = {Oikos}, year = {2010}, volume = {119}, pages = {12011209} } 
Schreiber, S. (2010), "Interactive effects of temporal correlations, spatial heterogeneity, and dispersal on population persistence", Proceedings of the Royal Society: Biological Sciences. Vol. 277, pp. 19071914.

Abstract: It is an ecological truism that population persistence depends on a population's growth rate when rare. To understand the interplay between temporal correlations, spatial heterogeneity, and dispersal on persistence, an analytic approximation for this growth rate is derived for partially mixing populations. Partial mixing has two effects on population growth. In the absence of temporal correlations in relative fitness, greater movement to patches with, on average, higher relative fitness increases population growth rates. In the absence of spatial heterogeneity in the average relative fitnesses, lower dispersal rates enhance growth rates when temporal correlations of relative fitness within a patch exceed temporal correlations in relative fitness between different patches. This approximation implies that metapopulations whose expected fitness in every patch is less than one can persist if there are positive temporal correlations in relative fitness, sufficiently weak spatial correlations, and sufficiently low dispersal rates. It also implies that movement into lowerquality habitats is optimal whenever the net variation in percapita growth rates is sufficiently larger than the mean difference in percapita growth rates. Moreover, temporal correlations, whether they be negative or positive, can enhance population growth for optimal dispersal rates. 
BibTeX:
@article{prsb10, author = {S.J. Schreiber}, title = {Interactive effects of temporal correlations, spatial heterogeneity, and dispersal on population persistence}, journal = {Proceedings of the Royal Society: Biological Sciences}, year = {2010}, volume = {277}, pages = {19071914} } 
Schreiber, S.J. & Saltzman, E. (2009), "Evolution of predator and prey movement into sink habitats", American Naturalist. Vol. 174, pp. 6881.

Abstract: Mathematical models of predatorprey interactions in a patchy landscape are used to explore the evolution of dispersal into sink habitats. When evolution is constrained to a single trophic level, three evolutionary outcomes are observed. If predatorprey dynamics are sufficiently stable in source habitats, then there is an evolutionarily stable strategy (ESS) corresponding to sedentary phenotypes that specialize on source habitats. However, if predatorprey dynamics are sufficiently unstable in source habitats, then either an ESS corresponding to dispersive phenotypes utilizing both source and sink habitats or an evolutionary stable coalition (ESC) between dispersive and sedentary phenotypes emerges. ESCs only occur if dispersal into sink habitats can stabilize the predatorprey interactions. When evolution of dispersal proceeds at both trophic levels, nine evolutionary outcomes corresponding to any combination of specialists and generalists at one or both trophic levels were observed. Coevolution is largely topdown driven. If the predator mortality rate in sink habitats is low, then selection pressure for predator movement into sink habitats can forestall the evolution of prey sink populations. Alternatively, if this mortality rate is high, then the predators ultimately play a sedentary ESS. Only at intermediate predator mortality rates is there selection for predator and prey movement into sink habitats. These results suggest that the instability of predatorprey interactions may foster speciation near species borders. Moreover, they illustrate an evolutionary paradox of enrichment in which enriching source habitats can result in a loss of phenotypic diversity. !! 
BibTeX:
@article{amnat09a, author = {S. J. Schreiber and E. Saltzman}, title = {Evolution of predator and prey movement into sink habitats}, journal = {American Naturalist}, year = {2009}, volume = {174}, pages = {6881} } 
Schreiber, S.J. & LloydSmith, J.O. (2009), "Invasion dynamics in spatially heterogenous environments", American Naturalist. Vol. 174, pp. 490505.

Abstract: Biological invasions, including infectious disease outbreaks and biocontrol introductions, often involve small numbers of individuals arriving in spatially heterogeneous environments. Small numbers lead to demographic stochasticity, and spatial heterogeneity means that establishment success depends critically on the introduction sites and movement patterns of invaders. We present a general stochastic modeling framework to address how spatial heterogeneity and movement patterns determine establishment success, population growth, and rates of spatial spread. For dispersallimited populations, our analysis reveals that spatial heterogeneity increases the expected population growth rate and that local reproductive numbers determine establishment success. Higher dispersal rates decrease the expected population growth rate, but can enhance establishment success, particularly when movement patterns are positively correlated with local reproductive numbers. We also find that several small, randomly distributed propagules of invaders are more likely to succeed than a single large propagule. Even if invasions are ultimately successful, there may be substantial time lags before an invader reaches observable densities. These time lags are longer for invasions into patches where extinction risk is high and in landscapes where metapopulationscale population growth rate is low, while the opposite holds true for rates of spatial spread. Sensitivity analysis of our models provides guidance for control efforts.!! 
BibTeX:
@article{amnat09b, author = {S. J. Schreiber and J. O. LloydSmith}, title = {Invasion dynamics in spatially heterogenous environments}, journal = {American Naturalist}, year = {2009}, volume = {174}, pages = {490505} } 
Kon, R. & Schreiber, S.J. (2009), "Host and multiple parasitoid dynamics with egg limitation", SIAM Journal of Applied Mathematics. Vol. 69, pp. 959976.

Abstract: To address the contentious issue of multiple parasitoid introductions in classical biological control, a discretetime model of multiparasitoidhost interactions that accounts for host densitydependence and egg limitation is introduced and analyzed. For parasitoids that are egglimited but not searchlimited, the model is proven to exhibit four types of dynamics: host failure in which the host goes extinct in the presence or absence of the parasitoids, parasitoid driven extinction in which the parasitoid complex invariably drives the host extinct, host persistence, and conditional host persistence in which depending on the initial ratios of host to parasitoid densities the host is either driven extinct or persists. In the case of host persistence, the dynamics of the system are shown to be asymptotic to the dynamics of an appropriately defined onedimensional difference equation. The results illustrate how the establishment of one or more parasitoids can facilitate the invasion of another parasitoid and how a complex of parasitoids can drive a host extinct despite every species in the complex being unable to do so. The effects of including search limitation are also explored. 
BibTeX:
@article{siap09, author = {R. Kon and S. J. Schreiber}, title = {Host and multiple parasitoid dynamics with egg limitation}, journal = {SIAM Journal of Applied Mathematics}, year = {2009}, volume = {69}, pages = {959976} } 
Benaïm, M. & Schreiber, S.J. (2009), "Persistence of structured populations in random environments", Theoretical Population Biology. Vol. 76, pp. 1934.

Abstract: Environmental fluctuations often have different impacts on individuals that differ in size, age, or spatial location. To understand how population structure, environmental fluctuations, and densitydependent interactions influence population dynamics, we provide a general theory for persistence for densitydependent matrix models in random environments. For populations with compensating density dependence, exhibiting ``bounded'' dynamics, and living in a stationary environment, we show that persistence is determined by the stochastic growth rate (alternatively, dominant Lyapunov exponent) when the population is rare. If this stochastic growth rate is negative, then the total population abundance goes to zero with probability one. If this stochastic growth rate is positive, there is a unique positive stationary distribution. Provided there are initially some individuals in the population, the population converges in distribution to this stationary distribution and the empirical measures almost surely converge to the distribution of the stationary distribution. For models with overcompensating densitydependence, weaker results are proven. Methods to estimate stochastic growth rates are presented. To illustrate the utility of these results, applications to unstructured, spatially structured, and stagestructured population models are given. For instance, we show that diffusively coupled sink populations can persist provided that within patch fitness is sufficiently variable in time but not strongly correlated across space. !! 
BibTeX:
@article{tpb09, author = {M. Benaïm and S. J. Schreiber}, title = {Persistence of structured populations in random environments}, journal = {Theoretical Population Biology}, year = {2009}, volume = {76}, pages = {1934} } 
Schreiber, S.J. & Rudolf, V. (2008), "Crossing habitat boundaries: Coupling dynamics of ecosystems through complex life cycles", Ecology Letters. Vol. 11, pp. 576587.

Abstract: Ecosystems are often indirectly connected through consumers with complex life cycles (CLC), in which different life stages inhabit different ecosystems. Using a structured consumer resource model that accounts for the independent effects of two resources on consumer growth and reproductive rates, we show that such indirect connections between ecosystems can result in alternative stable states characterized by adult dominated and juvenile dominated consumer populations. As a consequence, gradual changes in ecosystem productivity or mortality rates of the consumer can lead to dramatic and abrupt regime shifts across different ecosystems, hysteresis, and counterintuitive changes in the consumer abundances. Whether these counterintuitive or abrupt responses occur depend on the relative productivity of both habitats and which consumer lifestage inhabits the manipulated ecosystem. These results demonstrate the strong yet complex interactions between ecosystems coupled through consumers with CLC and the need to think across ecosystems to reliably predict the consequences of natural or anthropogenic changes. !! 
BibTeX:
@article{ecolets08, author = {S. J. Schreiber and V. Rudolf}, title = {Crossing habitat boundaries: Coupling dynamics of ecosystems through complex life cycles}, journal = {Ecology Letters}, year = {2008}, volume = {11}, pages = {576587} } 
Lipcius, R.N., Eggleston, D.B., Schreiber, S.J., Seitz, R.D., Shen, J., Sisson, M., Stockhausen, W.T. & Wang, H.V. (2008), "Metapopulation connectivity and stock enhancement of marine species", Reviews in Fishery Science. Vol. 16, pp. 101110.

Abstract: Various biophysical systems exhibit characteristics of metapopulation and network structure. The specific type of metapopulation or network structure can have substantially different effects on metapopulation dynamics of marine species with open populations displaying varying degrees of connectivity between subpopulations, and thus can have major consequences on stock enhancement efforts. We investigate the role of connectivity in metapopulation dynamics of the blue crab, Callinectes sapidus, and the Eastern oyster, Crassostrea virginica, with three dimensional hydrodynamic models simulating advection and diffusion. In the case of the blue crab, we model a metapopulation comprised of primary (i.e. seagrass beds) and secondary (i.e. salt marsh fringed coves and shorelines) nursery habitats, and spatially distinct spawning grounds connected via migration corridors. In the model simulations, we distinguish nursery habitats that are recruitment limited, and therefore optimal candidates for stock enhancement through release of hatcheryreared or translocated juveniles. In the case of the Eastern oyster, we model connectivity between numerous oyster reefs (i.e., subpopulations) positioned according to historical observations. Model simulations produce estimates of the degree of connectivity between all pairs of oyster reefs, which subsequently permits assessment of the diversity of patterns in network connectivity. From these results we distinguish the major characteristic types of connectivity patterns among oyster reefs, we identify those reefs most suitable for broodstock enhancement, and we discuss the means by which oyster reef networks, such as those occurring throughout Chesapeake Bay, may be enhanced successfully. 
BibTeX:
@article{rfs08, author = {R.~N. Lipcius and D.~B. Eggleston and S.~J. Schreiber and R.~D. Seitz and J.~Shen and M.~Sisson and W.~T. Stockhausen and H.~V. Wang}, title = {Metapopulation connectivity and stock enhancement of marine species}, journal = {Reviews in Fishery Science}, year = {2008}, volume = {16}, pages = {101110} } 
Schreiber, S.J. (2007), "On persistence and extinction of randomly perturbed dynamical systems", Discrete and Continous Dynamical Systems B. Vol. 7, pp. 457463.

BibTeX:
@article{dcds07, author = {S. J. Schreiber}, title = {On persistence and extinction of randomly perturbed dynamical systems}, journal = {Discrete and Continous Dynamical Systems B}, year = {2007}, volume = {7}, pages = {457463} } 
Schreiber, S.J. (2007), "Periodicity, persistence, and collapse in hostparasitoid systems with egg limitation", Journal of Biological Dynamics. Vol. 1, pp. 273  287.

Abstract: There is an emerging consensus that parasitoids are limited by the number of eggs which they can lay as well as the amount of time they can search for their hosts. Since egg limitation tends to destabilize hostparasitoid dynamics, successful control of insect pests by parasitoids requires additional stabilizing mechanisms such as heterogeneity in the distribution of parasitoid attacks and host densitydependence. To better understand how egg limitation, search limitation, heterogeneity in parasitoid attacks, and host densitydependence influence hostparasitoid dynamics, discrete time models accounting for these factors are analyzed. When parasitoids are purely egglimited, a complete anaylsis of the hostparasitoid dynamics are possible. The analysis implies that the parasitoid can invade the host system only if the parasitoid's intrinsic fitness exceeds the host's intrinsic fitness. When the parasitoid can invade, there is a critical threshold, CV*>1, of the coefficient of variation (CV) of the distribution of parasitoid attacks that determines that outcome of the invasion. If parasitoid attacks sufficiently aggregated (i.e., CV>CV*), then the host and parasitoid coexist. Typically (in a topological sense), this coexistence is shown to occur about a periodic attractor or a stable equilibrium. If the parasitoid attacks are sufficiently random (i.e. CV 
BibTeX:
@article{jbd07, author = {Schreiber, S. J.}, title = {Periodicity, persistence, and collapse in hostparasitoid systems with egg limitation}, journal = {Journal of Biological Dynamics}, year = {2007}, volume = {1}, pages = {273  287} } 
LloydSmith, J.O., Schreiber, S.J. & Getz, W.M. (2006), "Moving beyond averages: individuallevel variation in disease transmission", In Mathematical studies on human disease dynamics. Providence, RI Vol. 410, pp. 235258. Amer. Math. Soc..

Abstract: It is common practice in disease modeling studies to characterize groups or subgroups using populationaverage parameters, most importantly the basic reproductive number, R0 . This approach overlooks variation at the individual level, which is caused by many factors. In this paper we show evidence of significant individuallevel variation in transmission patterns for several diseases, and discuss how this can be incorporated into epidemiological models. We introduce a natural generalization of R0 : the `individual reproductive number', v, which is the expected number of secondary cases caused by a given infected individual. Individual reproductive numbers for a population are drawn from a continuous probability distribution with mean equal to R0 (or to the effective reproductive number, R, if the population is not wholly susceptible). In this framework, superspreading events correspond to extreme values from the righthand tail of the distribution of v, and we propose a precise and generalizable definition of superspreading events based on probabilistic considerations. We analyze detailed transmission data for a range of directlytransmitted diseases, and find that conventional models assuming homogeneous transmission cannot account for observed patterns. Analysis of a branching process model incorporating individuallevel heterogeneity reveals that observed levels of variation cause invasion dynamics to differ dramatically from predictions based on population averages. We explore the implications of these findings for outbreak control policies, demonstrating that individualspecific control measures are more likely to stop an outbreak than populationwide measures when both have the same effect on R0 . We also highlight the effectiveness of measures targeting highly infectious individuals, and discuss how our results relate to recentlyproposed surveillance methods for emerging diseases. We conclude by discussing future challenges in empirical and theoretical studies. 
BibTeX:
@incollection{book06, author = {J. O. LloydSmith and S. J. Schreiber and W. M. Getz}, title = {Moving beyond averages: individuallevel variation in disease transmission}, booktitle = {Mathematical studies on human disease dynamics}, publisher = {Amer. Math. Soc.}, year = {2006}, volume = {410}, pages = {235258} } 
Schreiber, S.J. (2006), "Hostparasitoid dynamics of a generalized Thompson model", J. Math. Biol.. Vol. 52, pp. 719732.

Abstract: A discretetime hostparasitoid model including hostdensity dependence and a generalized Thompson escape function is analyzed. This model assumes that parasitoids are egglimited but not searchlimited, and is proven to exhibit five types of dynamics: host failure in which the host goes extinct in the parasitoid's presence or absence, unconditional parasitoid failure in which the parasitoid always goes extinct while the host persists, conditional parasitoid failure in the host and the parasitoid go extinct or coexist depending on the initial hostparasitoid ratio, parasitoid driven extinction in which the parasitoid invariably drives the host to extinction, and coexistence in which the host and parasitoid coexist about a global attractor. The latter two dynamics only occur when the parasitoid's maximal rate of growth exceeds the host's maximal rate of growth. Moreover, coexistence requires parasitism events to be sufficiently aggregated. Small additive noise is proven to alter the dynamical outcomes in two ways. The addition of noise to parasitoid driven extinction results in random outbreaks of the host and parasitoid with varying intensity. Additive noise converts conditional parasitoid failure to unconditional parasitoid failure. Implications for classical biological control are discussed. 
BibTeX:
@article{jmb06, author = {S. J. Schreiber}, title = {Hostparasitoid dynamics of a generalized Thompson model}, journal = {J. Math. Biol.}, year = {2006}, volume = {52}, pages = {719732} } 
Schreiber, S.J. (2006), "Persistence despite perturbations for interacting populations", Journal of Theoretical Biology. Vol. 242, pp. 84452.

Abstract: Two definitions of persistence despite perturbations in deterministic models are presented. The first definition, persistence despite frequent small perturbations, is shown to be equivalent to the existence of a positive attractor i.e. an attractor bounded away from extinction. The second definition, persistence despite rare large perturbations, is shown to be equivalent to permanence i.e. a positive attractor whose basin of attraction includes all positive states. Both definitions set up a natural dichotomy for classifying models of interacting populations. Namely, a model is either persistent despite perturbations or not. When it is not persistent, it follows that all initial conditions are prone to extinction due to perturbations of the appropriate type. For frequent small perturbations, this method of classification is shown to be generically robust: there is a dense set of models for which persistent (respectively, extinction prone) models lies within an open set of persistent (resp. extinction prone) models. For rare large perturbations, this method of classification is shown not to be generically robust. Namely, work of Josef Hofbauer and the author have shown there are open sets of ecological models containing a dense sets of permanent models and a dense set of extinction prone models. The merits and drawbacks of these different definitions are discussed. 
BibTeX:
@article{jtb06, author = {S. J. Schreiber}, title = {Persistence despite perturbations for interacting populations}, journal = {Journal of Theoretical Biology}, year = {2006}, volume = {242}, pages = {84452} } 
Li, C.K. & Schreiber, S.J. (2006), "On dispersal and population growth for multistate matrix models", Linear Algebra Appl.. Vol. 418(23), pp. 900912.

Abstract: To describe the dynamics of stagestructured populations with m stages living in n patches, we consider matrix models of the form SD, where S is a block diagonal matrix with n x n column substochastic matrices S1,..., Sm along the diagonal and D is a block matrix whose blocks are n x n nonnegative diagonal matrices. The matrix S describes movement between patches and the matrix D describes growth and reproduction within the patches. Consider the multiple arc directed graph G consisting of the directed graphs corresponding to the matrices S1,..., Sm, where each directed graph is drawn in a different color. We say G has a polychromatic cycle if G has a directed cycle that includes arcs of more than one color. We prove that p(SD) < p(D) for all block matrices D with nonnegative diagonal blocks if and only if G has no polychromatic cycle. Applications to ecological models are presented. 
BibTeX:
@article{laa06, author = {C. K. Li and S. J. Schreiber}, title = {On dispersal and population growth for multistate matrix models}, journal = {Linear Algebra Appl.}, year = {2006}, volume = {418}, number = {23}, pages = {900912} } 
Schreiber, S.J., Lipcius, R., Seitz, R. & Long, C. (2006), "Dancing between the devil and the deep blue sea: The stabilizing effect of enemyfree sinks and victimless sinks", Oikos. Vol. 113, pp. 6781.

Abstract: Theoretical and empirical studies have shown that enemyvictim interactions in spatially homogenous environments can exhibit diverging oscillations which result in the extinction of one or both species. For enemyvictim models with overlapping generations, we investigate the dynamical implications of spatial heterogeneity created by enemyfree sinks or victimless sinks. An enemyfree sink is a behavioral, physiological or ecological state that reduces or eliminates the victim's vulnerability to the enemy but cannot sustain the victim population. For victims that move in an idealfree manner, we prove that the inclusion of an enemyfree sink shifts the population dynamics from diverging oscillations to stable oscillations. During these stable oscillations, the victim disperses in an oscillatory manner between the enemyfree sink and the enemyoccupied patch. Enemyfree sinks with lower mortality rates exhibit oscillations with smaller amplitudes and longer periods. A victimless sink, on the other hand, is a behavioral, physiological or ecological state in which the enemy has limited (or no) access to its victims. For enemies that move in an idealfree manner, we prove that victimless sinks also stabilize diverging oscillations. Simulations suggest that suboptimal behavior due to information gathering or learning limitations amplify oscillations for systems with enemyfree sinks and dampen oscillations for systems with victimless sinks. These results illustrate that the coupling of a sink created by unstable enemyvictim interactions and a sink created by unsuitable environmental conditions can result in population persistence at the landscape level. 
BibTeX:
@article{oikos06, author = {S. J. Schreiber and R. Lipcius and R. Seitz and C. Long}, title = {Dancing between the devil and the deep blue sea: The stabilizing effect of enemyfree sinks and victimless sinks}, journal = {Oikos}, year = {2006}, volume = {113}, pages = {6781} } 
Schreiber, S. & Vejdani, M. (2006), "Handling time promotes the coevolution of aggregation in predatorprey systems", Proceedings of the Royal Society: Biological Sciences. Vol. 273, pp. 185191.

Abstract: Predators often have type II functional responses and live in environments where their life history traits as well as those of their prey vary from patch to patch. To understand how spatial heterogeneity and predator handling times influence the coevolution of patch preferences and ecological stability, we perform an ecological and evolutionary analysis of a NicholsonBailey type model. We prove that coevolutionarily stable prey and searching predators prefer patches that in isolation support higher prey and searching predator densities, respectively. Using this fact, we determine how environmental variation and predator handling times influence the spatial patterns of patch preferences, population abundances and percapita predation rates. In particular, long predator handling times are shown to result in the coevolution of predator and prey aggregation. An analytic expression characterizing ecological stability of the coevolved populations is derived. This expression implies that contrary to traditional theoretical expectations, predator handling time can stabilize predatorprey interactions through its coevolutionary influence on patch preferences. These results are shown to have important implications for classical biological control. !! 
BibTeX:
@article{prsb06, author = {Schreiber, S.J. and M. Vejdani}, title = {Handling time promotes the coevolution of aggregation in predatorprey systems}, journal = {Proceedings of the Royal Society: Biological Sciences}, year = {2006}, volume = {273}, pages = {185191} } 
Jacobs, F. & Schreiber, S.J. (2006), "Random perturbations of dynamical systems with absorbing states", SIAM Journal of Applied Dynamical Systems. Vol. 5, pp. 293312.

BibTeX:
@article{siads06, author = {F. Jacobs and S. J. Schreiber}, title = {Random perturbations of dynamical systems with absorbing states}, journal = {SIAM Journal of Applied Dynamical Systems}, year = {2006}, volume = {5}, pages = {293312} } 
Kirkland, S., Li, C. & Schreiber, S.J. (2006), "On the evolution of dispersal in patchy landscapes", SIAM Journal on Applied Mathematics. Vol. 66(4), pp. 13661382.

Abstract: To better understand the evolution of dispersal in spatially heterogeneous landscapes, we study difference equation models of populations that reproduce and disperse in a landscape consisting of k patches. The connectivity of the patches and costs of dispersal are determined by a k x k column substochastic matrix S, where Sij represents the fraction of dispersing individuals from patch j that end up in patch i. Given S, a dispersal strategy is a k x 1 vector whose ith entry gives the probability pi that individuals disperse from patch i. If all of the pi's are the same, then the dispersal strategy is called unconditional; otherwise it is called conditional. For two competing populations of unconditional dispersers, we prove that the slower dispersing population (i.e., the population with the smaller dispersal probability) displaces the faster dispersing population. Alternatively, for populations of conditional dispersers without any dispersal costs (i.e., S is column stochastic and all patches can support a population), we prove that there is a one parameter family of strategies that resists invasion attempts by all other strategies.!! 
BibTeX:
@article{siap06, author = {S. Kirkland and C.K. Li and S. J. Schreiber}, title = {On the evolution of dispersal in patchy landscapes}, journal = {SIAM Journal on Applied Mathematics}, year = {2006}, volume = {66}, number = {4}, pages = {13661382} } 
Schreiber, S.J. & Kelton, M. (2005), "Sink habitats can alter ecological outcomes for competing species", Journal of Animal Ecology. Vol. 74(6), pp. 9951004.

Abstract: 1. Species often compete for breeding sites in heterogeneous landscapes consisting of sources and sinks. To understand how the presence or absence of sink breeding sites influence ecological outcomes, we extend Pulliam's sourcesink model to competing species. 2. In a homogeneous landscape consisting of source sites, we prove that one species, the 'superior' competitor, competitively excludes the other. Dominance is determined by a simple rule: the species that at equilibrium acquires new breeding sites at a faster rate dominates. 3. We prove that the inclusion of sink sites can alter this ecological outcome by either mediating coexistence, reversing competitive dominance, or facilitating a priority effect. 4. Sinkmediated coexistence requires the species to exhibit asymmetries in acquiring sink sites, the 'inferior' species to have a competitive advantage on sink sites and the ratio of sink to source sites be sufficiently low. 5. For example, if the sink breeding sites are competitive refuges for the 'inferior' competitor and not too low in quality, coexistence occurs if the number of sink sites lies below a threshold. Alternatively, when the number of sink sites exceeds this threshold, competitive dominance is reversed and the 'superior' competitor is displaced. 6. Counterintuitively, despite being unable to support species in isolation, sink habitats embedded in a geographical mosaic of sources and sinks can enhance biodiversity by mediating coexistence or alter species composition by reversing competitive interactions. 
BibTeX:
@article{jae05, author = {S. J. Schreiber and M. Kelton}, title = {Sink habitats can alter ecological outcomes for competing species}, journal = {Journal of Animal Ecology}, year = {2005}, volume = {74}, number = {6}, pages = {9951004} } 
*Ruggieri, E. & Schreiber, S.J. (2005), "The dynamics of the SchoenerPolisHolt model of intraguild predation", Math. Biosci. Eng.. Vol. 2(2), pp. 279288.

Abstract: Intraguild predation occurs when one species (the intraguild predator) predates on and competes with another species (the intraguild prey). A classic model of this interaction was introduced by Gary Polis and Robert Holt building on a model of competing species by Thomas Schoener. A global analysis reveals that this model exhibits generically six dynamics: extinction of one or both species; coexistence about a globally stable equilibrium; contingent exclusion in which the first established species prevents the establishment of the other species; contingent coexistence in which coexistence or displacement of the intraguild prey depend on initial conditions; exclusion of the intraguild prey; and exclusion of the intraguild predator. Implications for biological control and community ecology are discussed 
BibTeX:
@article{mbe05, author = {E. *Ruggieri and S. J. Schreiber}, title = {The dynamics of the SchoenerPolisHolt model of intraguild predation}, journal = {Math. Biosci. Eng.}, year = {2005}, volume = {2}, number = {2}, pages = {279288} } 
LloydSmith, J., Schreiber, S.J., Kopp, P.E. & Getz, W.M. (2005), "Superspreading and the impact of individual variation on disease emergence", Nature. , pp. 355359.

Abstract: Populationlevel analyses often use average quantities to describe heterogeneous systems, particularly when variation does not arise from identifiable groups. A prominent example, central to our current understanding of epidemic spread, is the basic reproductive number, R0, which is defined as the mean number of infections caused by an infected individual in a susceptible population. Population estimates of R0 can obscure considerable individual variation in infectiousness, as highlighted during the global emergence of severe acute respiratory syndrome (SARS) by numerous `superspreading events' in which certain individuals infected unusually large numbers of secondary cases. For diseases transmitted by nonsexual direct contacts, such as SARS or smallpox, individual variation is difficult to measure empirically, and thus its importance for outbreak dynamics has been unclear. Here we present an integrated theoretical and statistical analysis of the influence of individual variation in infectiousness on disease emergence. Using contact tracing data from eight directly transmitted diseases, we show that the distribution of individual infectiousness around R0 is often highly skewed. Model predictions accounting for this variation differ sharply from averagebased approaches, with disease extinction more likely and outbreaks rarer but more explosive. Using these models, we explore implications for outbreak control, showing that individualspecific control measures outperform populationwide measures. Moreover, the dramatic improvements achieved through targeted control policies emphasize the need to identify predictive correlates of higher infectiousness. Our findings indicate that superspreading is a normal feature of disease spread, and to frame ongoing discussion we propose a rigorous definition for superspreading events and a method to predict their frequency. !! 
BibTeX:
@article{nature05, author = {J. LloydSmith and S. J. Schreiber and P. E. Kopp and W. M. Getz}, title = {Superspreading and the impact of individual variation on disease emergence}, journal = {Nature}, year = {2005}, pages = {355359} } 
Keagy, J., Schreiber, S.J. & Cristol, D.A. (2005), "Replacing Sources with Sinks: When Do Populations Go Down the Drain?", Restoration Ecology. Vol. 13(3), pp. 529535.

BibTeX:
@article{re05, author = {J. Keagy and S. J. Schreiber and D. A. Cristol}, title = {Replacing Sources with Sinks: When Do Populations Go Down the Drain?}, journal = {Restoration Ecology}, year = {2005}, volume = {13}, number = {3}, pages = {529535} } 
Benaïm, M., Schreiber, S.J. & Tarrés, P. (2004), "Generalized urn models of evolutionary processes", Annals of Applied Probability. Vol. 14, pp. 14551478.

Abstract: Generalized Pólya urn models can describe the dynamics of finite populations of interacting genotypes. Three basic questions these models can address are: Under what conditions does a population exhibit growth? On the event of growth, at what rate does the population increase? What is the longterm behavior of the distribution of genotypes? To address these questions, we associate a mean limit ordinary differential equation (ODE) with the urn model. Previously, it has been shown that on the event of population growth, the limiting distribution of genotypes is a connected internally chain recurrent set for the mean limit ODE. To determine when growth and convergence occurs with positive probability, we prove two results. First, if the mean limit ODE has an ``attainable'' attractor at which growth is expected, then growth and convergence toward this attractor occurs with positive probability. Second, the population distribution almost surely does not converge to sets where growth is not expected and almost surely does not converge to ``nondegenerate'' unstable equilibria or periodic orbits of the mean limit ODE. Applications to stochastic analogs of the replicator equations and fertilityselection equations of population genetics are given. !! 
BibTeX:
@article{aap04, author = {M. Benaïm and S. J. Schreiber and P. Tarrés}, title = {Generalized urn models of evolutionary processes}, journal = {Annals of Applied Probability}, year = {2004}, volume = {14}, pages = {14551478} } 
Schreiber, S.J. (2004), "Coexistence for species sharing a predator", Journal of Differential Equations. Vol. 196, pp. 209225.

BibTeX:
@article{jde04, author = {Schreiber, S. J.}, title = {Coexistence for species sharing a predator}, journal = {Journal of Differential Equations}, year = {2004}, volume = {196}, pages = {209225} } 
Hofbauer, J. & Schreiber, S.J. (2004), "To persist or not to persist?", Nonlinearity. Vol. 17, pp. 13931406.

BibTeX:
@article{nonlinearity04, author = {Hofbauer, J. and Schreiber, S. J.}, title = {To persist or not to persist?}, journal = {Nonlinearity}, year = {2004}, volume = {17}, pages = {13931406} } 
Schreiber, S.J. & Rittenhouse, S. (2004), "From simple rules to cycling in community assembly", Oikos. Vol. 105, pp. 349358.

Abstract: Simulation studies of community assembly have frequently observed two related phenomena: (1) the humpty dumpty effect in which communities can not be reconstructed by sequential invasions (i.e. single species invasions separated by long intervals of time) and (2) cycling between subcommunities. To better understand the mechanisms underlying these phenomena, we analyze a system consisting of two predators and two prey competing for a shared resource. We show how simple dominance rules (i.e. R and P rules) lead to cycling between subcommunities consisting of predatorprey pairs; predator and prey invasions alternatively lead to prey displacement via apparent competition and predator displacement via exploitative competition. We also show that these cycles are often dynamically unstable in the population phase space. More specifically, while for too slow invasion rates (i.e. sequential invasions) the system cycles indefinitely, faster invasion rates lead to coexistence of all species. In the later case, the assembly dynamics exhibit transient cycling between predatorprey subcommunities and the length of these transients decreases with the invasion rate and increases with habitat productivity. 
BibTeX:
@article{oikos04, author = {S. J. Schreiber and S. Rittenhouse}, title = {From simple rules to cycling in community assembly}, journal = {Oikos}, year = {2004}, volume = {105}, pages = {349358} } 
Schreiber, S.J. (2004), "On Allee effects in structured populations", Proc. Amer. Math. Soc.. Vol. 132(10), pp. 30473053 (electronic).

BibTeX:
@article{pams04, author = {S. J. Schreiber}, title = {On Allee effects in structured populations}, journal = {Proc. Amer. Math. Soc.}, year = {2004}, volume = {132}, number = {10}, pages = {30473053 (electronic)} } 
Schreiber, S.J. & Tobiason, G.A. (2003), "The evolution of resource use", Journal of Mathematical Biology. Vol. 47, pp. 5678.

Abstract: The evolution of a consumer exploiting two resources is investigated. The strategy x under selection represents the fraction of time or energy an individual invests into extracting the first resource. In the model, a dimensionless parameter alpha quantifies how simultaneous consumption of both resources influences consumer growth; alpha<0 corresponds to hemiessential resources, 0 
BibTeX:
@article{jmb03, author = {S. J. Schreiber and G. A. Tobiason}, title = {The evolution of resource use}, journal = {Journal of Mathematical Biology}, year = {2003}, volume = {47}, pages = {5678} } 
Schreiber, S.J. (2003), "Allee effects, chaotic transients, and unexpected extinctions", Theoretical Population Biology.

Abstract: Discrete time single species models with overcompensating density dependence and an Allee effect due to predator satiation and mating limitation are investigated. The models exhibit four behaviors: persistence for all initial population densities, bistability in which a population persists for intermediate initial densities and otherwise goes extinct, extinction for all initial densities, and essential extinction in which "almost every" initial density leads to extinction. For fastgrowing populations, these models show populations can persist at high levels of predatimi even though lower levels of predation lead to essential extinction. Alternatively, increasing the predator's handling time, the population's carrying capacity, or the likelihood of mating success may lead to essential extinction. In each of these cases, the mechanism behind these disappearances are chaotic dynamics driving populations below a critical threshold determined by the Allee effect. These disappearances are proceeded by chaotic transients that are proven to be approximately exponentially distributed in length and highly sensitive to initial population densities.!! 
BibTeX:
@article{tpb03, author = {S. J. Schreiber}, title = {Allee effects, chaotic transients, and unexpected extinctions}, journal = {Theoretical Population Biology}, year = {2003} } 
Schreiber, S., Fox, L. & Getz, W. (2002), "Parasitoid sex allocation affects coevolution of patch selection in hostparasitoid systems", Evolutionary Ecology Research. Vol. 4, pp. 701718.

Abstract: Previously, we have show that the coevolution of patch selection strategies of hosts and parasitoids in heterogeneous environments can lead to contrary habitat choices in which the hosts preferentially select patches that the parasitoids avoid. Since this work did not include the variable parasitoid sex ratios that have been found in field and laboratory systems with contrary choices, we extend previous analyses to determine how parasitoid sex allocation coevolves with host and parasitoid patch preferences. In our analysis, we assume the environment consists of two patch types: lower quality patches and higher quality patches. In the lower quality patches, hosts have a lower intrinsic rate of growth and female parasitoid larvae are less likely to survive than male parasitoid larvae. Our coevolutionary analysis reveals that the coevolved parasitoids preferentially search for hosts in higher quality patches, lay primarily female eggs on hosts encountered in these patches, and are more likely to lay male eggs on hosts encountered in the lower quality patches. As a coevolutionary response, the hosts lay twice as many eggs in the poorer patches as they would if parasitoid sex ratios did not evolve. We conclude by showing that the coevolution of parasitoid sex allocation with patch selection can stabilize hostparasitoid interactions even when coevolution of patch selection by itself does not.!! 
BibTeX:
@article{eer02, author = {S.J. Schreiber and L.R. Fox and W.M. Getz}, title = {Parasitoid sex allocation affects coevolution of patch selection in hostparasitoid systems}, journal = {Evolutionary Ecology Research}, year = {2002}, volume = {4}, pages = {701718} } 
Mierczyński, J. & Schreiber, S.J. (2002), "Kolmogorov vector fields with robustly permanent subsystems", J. Math. Anal. Appl.. Vol. 267(1), pp. 329337.

BibTeX:
@article{jmaa02, author = {Mierczyński, Janusz and Schreiber, Sebastian J.}, title = {Kolmogorov vector fields with robustly permanent subsystems}, journal = {J. Math. Anal. Appl.}, year = {2002}, volume = {267}, number = {1}, pages = {329337} } 
Schreiber, S.J. (2002), "Permanence of weakly coupled vector fields", SIAM J. Math. Anal.. Vol. 33(5), pp. 10481057 (electronic).

BibTeX:
@article{sima02, author = {Schreiber, Sebastian J.}, title = {Permanence of weakly coupled vector fields}, journal = {SIAM J. Math. Anal.}, year = {2002}, volume = {33}, number = {5}, pages = {10481057 (electronic)} } 
Schreiber, S.J. (2001), "Chaos and Sudden Extinction in Simple Ecological Models", Journal of Mathematical Biology. Vol. 42, pp. 239260.

Abstract: A class of truncated unimodal discretetime single species models for which low or high densities result in extinction in the following generation are considered. A classification of the dynamics of these maps into five types is proven: (i) extinction in finite time for all initial densities, (ii) semistability in which all orbits tend toward the origin or a semistable fixed point, (iii) bistability for which the origin and an interval bounded away from the origin are attracting, (iv) chaotic semistability in which there is an interval of chaotic dynamics whose compliment lies in the origin's basin of attraction and (v) essential extinction in which almost every (but not every) initial population density leads to extinction in finite time. Applying these results to the Logistic, Ricker and generalized BevertonHolt maps with constant harvesting rates, two birfurcations are shown to lead to sudden population disappearances: a saddle node bifurcation corresponding to a transition from bistability to extinction and a chaotic blue sky catastrophe corresponding to a transition from bistability to essential extinction. 
BibTeX:
@article{jmb01, author = {S. J. Schreiber}, title = {Chaos and Sudden Extinction in Simple Ecological Models}, journal = {Journal of Mathematical Biology}, year = {2001}, volume = {42}, pages = {239260} } 
Schreiber, S., Mills, N. & Gutierrez, A. (2001), "Hostlimited dynamics of autoparasitoids", Journal of Theoretical Biology. Vol. 212, pp. 141153.

BibTeX:
@article{schreiberetal01, author = {Schreiber, S.J. and Mills, N.J. and Gutierrez, A.P.}, title = {Hostlimited dynamics of autoparasitoids}, journal = {Journal of Theoretical Biology}, year = {2001}, volume = {212}, pages = {141153} } 
Schreiber, S.J. (2001), "Urn models, replicator processes, and random genetic drift", SIAM Journal of Applied Mathematics. Vol. 61, pp. 21482167.

Abstract: To understand the relative importance of natural selection and random genetic drift in finite but growing populations, the asymptotic behavior of a class of generalized Polya urns is studied using the method of ordinary differential equation (ODE). Of particular interest is the replicator process: two balls (individuals) are chosen from an urn (the population) at random with replacement and balls of the same colors (strategies) are added or removed according to probabilities that depend only on the colors of the chosen balls. Under the assumption that the expected number of balls being added always exceeds the expected number of balls being removed whenever balls are in the urn, the probability of nonextinction is shown to be positive. On the event of nonextinction, three results are proven: (i) the number of balls increases asymptotically at a linear rate, (ii) the distribution x(n) of strategies at the nth update is a "noisy" CauchyEuler approximation to the mean limit ODE of the process, and (iii) the limit set of x(n) is almost surely a connected internally chain recurrent set for the mean limit ODE. Under a stronger set of assumptions, it is shown that for any attractor of the mean limit ODE there is a positive probability that the limit set for x(n) lies in this attractor. Theoretical and numerical estimates for the probabilities of nonextinction and convergence to an attractor suggest that random genetic drift is more likely to overcome natural selection in small populations for which pairwise interactions lead to highly variable outcomes, and is less likely to overcome natural selection in large populations with the potential for rapid growth. 
BibTeX:
@article{siap01, author = {Schreiber, S. J.}, title = {Urn models, replicator processes, and random genetic drift}, journal = {SIAM Journal of Applied Mathematics}, year = {2001}, volume = {61}, pages = {21482167} } 
Schreiber, S., Fox, L. & Getz, W. (2000), "Coevolution of contrary choices in hostparasitoid systems", American Naturalist. , pp. 637648.

Abstract: We investigate patch selection strategies of hosts and parasitoids in heterogeneous environments. Previous theoretical work showed that when host traits vary among patches, coevolved populations of hosts and parasitoids make congruent choices (i.e.,hosts and parasitoids preferentially select the same patches) and exhibit direct density dependence in the distribution of percent parasitism. However, hostparasitoid systems in the field show a range of patterns in percent parasitism, while behavioral studies indicate that hosts and parasitoids can exhibit contrary choices (i.e., hosts avoid parches favored by the parasitoid). We extend previous theory by permitting lifehistory traits of the parasitoid as well as the host to vary among patches. Our analysis implies that in coevolutionarily stable populations, hosts preferentially select patches that intrinsically support higher host equilibrium numbers (i.e., the equilibrium number achieved by hosts when both populations are confined toa single patch) and that parasitoids preferentially select patches that intrinsically support higher parasitoid equilibrium numbers (i.e., the equilibrium number achieved by the parasitoids when both populations are confined to a patch). Using this result, we show how variation in lifehistory traits among patches leads to contrary or congruent choices or leads to direct density dependence, inverse density dependence, or density independence in the distribution of percent parasitism. In addition, we determine when populations playing the coevolutionarily stable strategies are ecologically stable. Our analysis shows that heterogeneous environments containing patches where the intrinsic rate of growth of the host and the survivorship rate ofthe parasitoid are low result in the coevolved populations exhibiting contrary choices and, as a result, promote ecological stability. 
BibTeX:
@article{amnat00, author = {S.J. Schreiber and L.R. Fox and W.M. Getz}, title = {Coevolution of contrary choices in hostparasitoid systems}, journal = {American Naturalist}, year = {2000}, pages = {637648} } 
Eisenberg, J.N.S., Washburn, J.O. & Schreiber, S.J. (2000), "The generalist feeding behaviors of Aedes sierrensis larvae and their effects on protozoan populations", Ecology. Vol. 81, pp. 921935.

Abstract: The generalist feeding strategy of larvae of the western tree hole mosquito, Aedes sierrensis, is central to understanding the communitylevel effects of the tritrophic interactions among mosquito larvae, midsized organisms (such as protozoa), and lowerlevel organisms (such as bacteria and fungi) in west coast phytotelmata. Laboratory microcosm experiments were conducted to characterize the feeding strategies of Ae. sierrensis larvae in the presence of multiple resource types (freeswimming protozoa and substratebound particulate material). In our experiment, we quantified the effects of varying instar numbers and profile, resource type, and refuge size on predation of protozoa. Refugia were explicitly modeled in our microcosms, representing the interstitial spaces of leaf litter and the wood lining of natural tree holes. Results from these microcosm experiments suggested that: (1) Even in the absence of larvae, the majority of protozoa resided in the smallvolume, resourcerich refugia. There was, however, a strong nonlinear and negative relationship between larval densities in the upper compartment and the protozoan densities in the refuge, suggesting that there was continual movement of protozoa between the two spaces. (2) Fourth instars harvested resources by filterfeeding at a higher rate than second instars. (3) As the level of substratebound particulate food was increased, the predation pressure by filterfeeding on the protozoa decreased. (4) As the refuge volume increased, the predation pressure on the protozoa decreased. We constructed a threestatevariable mathematical model describing the generalist feeding behavior of Ae. sierrensis larvae. The model system, with constant predator densities and two prey groups, exhibited full cooperativity; i.e., an increase in protozoa density resulted in a shift toward predation by filter feeding, while an increase in substratebound resources resulted in a shift toward predation by browsing. This indirect mutualism is mechanistically distinct from previously published systems and provides a potential mechanism for protozoan persistence in the presence of larval predation. 
BibTeX:
@article{ecology00, author = {J. N. S. Eisenberg and J. O. Washburn and S. J. Schreiber}, title = {The generalist feeding behaviors of Aedes sierrensis larvae and their effects on protozoan populations}, journal = {Ecology}, year = {2000}, volume = {81}, pages = {921935} } 
**Benaïm, M. & Schreiber, S.J. (2000), "Ergodic properties of weak asymptotic pseudotrajectores for semiflows", Journal of Dynamics and Differential Equations. Vol. 12, pp. 579598.

BibTeX:
@article{jdde00, author = {M. **Benaïm and S. J. Schreiber}, title = {Ergodic properties of weak asymptotic pseudotrajectores for semiflows}, journal = {Journal of Dynamics and Differential Equations}, year = {2000}, volume = {12}, pages = {579598} } 
Schreiber, S.J. (2000), "Criteria for $C^r$ robust permanence", Journal of Differential Equations. Vol. 162, pp. 400426.

Abstract: Let $dot x_i=x_if_i(x)$ ($i=1,n$) be a $C^r$ vector field that generates a dissipative flow $ on the positive cone of $. $ is called permanent if the boundary of the positive cone is repelling. $ is called br>$C^r$ robustly permanent if $ remains permanent for sufficiently small $C^r$ perturbations of the vector field. A necessary condition and a sufficient condition for $C^r$ robust permanence involving the average percapita growth rates $int f_i d with respect to invariant measures $ are derived. The necessary condition requires that $mu i int f_i d0$ where the infimum is taken over ergodic measures with compact support in the boundary of the positive cone. The sufficient condition requires that the boundary flow admits a Morse decomposition $M_1, M_k$ such that every $M_j$ satisfies $mu i int f_i dmu >0$ where the minimum is taken over invariant measures with support in $M_j$. As applications, we provide a sufficient condition for $C^r$ robust permanence of LotkaVolterra models and a topological characterization of $C^r$ robust permanence for food chain models. !! 
BibTeX:
@article{jde00, author = {S. J. Schreiber}, title = {Criteria for $C^r$ robust permanence}, journal = {Journal of Differential Equations}, year = {2000}, volume = {162}, pages = {400426} } 
Getz, W.M. & Schreiber, S.J. (1999), "Multiple time scales in consumerresource interactions", Annales Zooligici Fennici. Vol. 36, pp. 1120.

Abstract: Arguments regarding the appropriate form for the rate at which consumers extract biomass from resource populations hinge on relative time scales of underlying processes. Some ecologists argue that, because differential equation models imply instantaneous rates of change, time scale arguments do not hold. Here we point out that this reasoning is fallacious. We define three natural time scales for consumerresource interactions and demonstrate, using asymptotic methods of analysis, how relative differences in these scales lead to the formulation of models with qualitatively distinct dynamics. Further, we identify time scale and resource heterogeneity assumptions that constrain the R~* competition rule (i.e., the competitor that suppresses theresource to the lowest density excludes all other competitors), as well as clarify the dichotomy between Schoener's models of competition for overlapping and for partitioned resources. 
BibTeX:
@article{azf99, author = {W. M. Getz and S. J. Schreiber}, title = {Multiple time scales in consumerresource interactions}, journal = {Annales Zooligici Fennici}, year = {1999}, volume = {36}, pages = {1120} } 
Schreiber, S.J. & Gutierrez, A.P. (1999), "Insect invasions and community assembly", In Ecological Entomology. New York., pp. 425462. John Wiley & Sons. 
BibTeX:
@inproceedings{book99, author = {S. J. Schreiber and A. P. Gutierrez}, title = {Insect invasions and community assembly}, booktitle = {Ecological Entomology}, publisher = {John Wiley & Sons}, year = {1999}, pages = {425462} } 
Schreiber, S.J. (1999), "Successional stability of vector fields in dimension three", Proceedings of the American Mathematical Soceity. Vol. 127, pp. 9931002.

BibTeX:
@article{pams99, author = {S. J. Schreiber}, title = {Successional stability of vector fields in dimension three}, journal = {Proceedings of the American Mathematical Soceity}, year = {1999}, volume = {127}, pages = {9931002} } 
Schreiber, S.J. (1998), "On the stabilizing effect of specialist predators on founder controlled communities", Canadian Applied Mathematical Quarterly. Vol. 6, pp. 112.

Abstract: We study a generalized model of 2n interacting species consisting of n competing prey and n predators, each of which feeds exclusively upon one of the prey species. Under the assumption that the prey community is foundercontrolled (the positive equilibria determined by single prey species are asymptotically stable in prey phase space), it is shown that then predators can mediate uniform persistence when their mortality rates are sufficiently small. When this occurs, a repelling heteroclinic network on the boundary of the positive orthant is formed in which the removal of any predator leads to a system with a globally asymptotically stable equilibrium that only supports a single species.!! 
BibTeX:
@article{camq98, author = {S. J. Schreiber}, title = {On the stabilizing effect of specialist predators on founder controlled communities}, journal = {Canadian Applied Mathematical Quarterly}, year = {1998}, volume = {6}, pages = {112} } 
Regev, U., Gutierrez, A.P., Schreiber, S.J. & Zilberman, D. (1998), "Bioeconomic foundations of renewable resource exploitation", Ecological Economics. Vol. 26, pp. 227242.

BibTeX:
@article{ecoecon98, author = {U. Regev and A. P. Gutierrez and S. J. Schreiber and D. Zilberman}, title = {Bioeconomic foundations of renewable resource exploitation}, journal = {Ecological Economics}, year = {1998}, volume = {26}, pages = {227242} } 
Schreiber, S.J. & Gutierrez, A.P. (1998), "A supplydemand perspective of species invasions: Applications to biological control", Ecological Modelling. Vol. 106, pp. 2745.

BibTeX:
@article{ecomod98, author = {S. J. Schreiber and A. P. Gutierrez}, title = {A supplydemand perspective of species invasions: Applications to biological control}, journal = {Ecological Modelling}, year = {1998}, volume = {106}, pages = {2745} } 
Schreiber, S.J. (1998), "On growth rates of subadditive functions for semiflows", Journal of Differential Equations. Vol. 148, pp. 334350.

BibTeX:
@article{jde98, author = {S. J. Schreiber}, title = {On growth rates of subadditive functions for semiflows}, journal = {Journal of Differential Equations}, year = {1998}, volume = {148}, pages = {334350} } 
Schreiber, S.J. (1997), "Expansion rates and Lyapunov exponents", Discrete and Continous Dynamical Systems. Vol. 3, pp. 433438.

BibTeX:
@article{dcds97, author = {S. J. Schreiber}, title = {Expansion rates and Lyapunov exponents}, journal = {Discrete and Continous Dynamical Systems}, year = {1997}, volume = {3}, pages = {433438} } 
Schreiber, S.J. (1997), "Gerneralist and specialist predators that mediate permanence in ecological communities", Journal of Mathematical Biology. Vol. 36, pp. 133148.

Abstract: General dynamic models of systems with two prey and one or two predators are considered. After rescaling the equations so that both prey have the same intrinsic rate of growth, it is shown that there exists a generalist predator that can mediate permanence if and only if there is a population density of a prey at which its percapita growth rate is positive yet less than its competitor's invasion rate. In particular, this result implies that if the outcome of competition between the prey is independent of initial conditions, then there exists a generalist predator that mediates permanence. On the other hand, if the outcome of competition is contingent upon initial conditions (i.e., the prey are bistable), then there may not exist a suitable generalist predator. For example, bistable prey modeled by the AyalaGilpin (thetaLogistic) equations can be stabilized if and only if theta<1 for one of the prey. It is also shown that two specialist predators always can mediate permanence between bistable prey by creating a repelling heteroclinic cycle consisting of fixed points and limit cycles. 
BibTeX:
@article{jmb97, author = {S. J. Schreiber}, title = {Gerneralist and specialist predators that mediate permanence in ecological communities}, journal = {Journal of Mathematical Biology}, year = {1997}, volume = {36}, pages = {133148} } 
Schreiber, S.J. (1996), "Global stability in consumerresource cascades", Journal of Mathematical Biology. Vol. 35, pp. 3748.

Abstract: Models of population growth in consumerresource cascades (serially arranged containers with a dynamic consumer population, v, receiving a flow of resource, u, from the previous container) with a functional response of the form h(u/v^b) are investigated. For 1>b>0, it is shown that these models have a globally stable equilibrium. As a result, two conclusions can be drawn: (1) Consumer density dependence in the functional or in the percapita numerical response can result in persistence of the consumer population in all containers. (2) In the absence of consumer density dependence, the consumer goes extinct in all containers except possibly the first. Several variations of this model are discussed including replacing discrete containers by a spatial continuum and introducing a dynamic resource. 
BibTeX:
@article{jmb96, author = {S. J. Schreiber}, title = {Global stability in consumerresource cascades}, journal = {Journal of Mathematical Biology}, year = {1996}, volume = {35}, pages = {3748} } 
Schreiber, S.J. (1995), "Nonuniformly hyperbolic dynamics". School: University of California, Berkeley.

BibTeX:
@phdthesis{schreiber95, author = {S. J. Schreiber}, title = {Nonuniformly hyperbolic dynamics}, school = {University of California, Berkeley}, year = {1995} } 
Gutierrez, A.P., Mills, N.J., Schreiber, S.J. & Ellis, C.K. (1994), "A phsysiologically based tritrophic perspective on bottomup topdown regulation of populations", Ecology. Vol. 75, pp. 22272242.

BibTeX:
@article{ecology94, author = {A. P. Gutierrez and N. J. Mills and S. J. Schreiber and C. K. Ellis}, title = {A phsysiologically based tritrophic perspective on bottomup topdown regulation of populations}, journal = {Ecology}, year = {1994}, volume = {75}, pages = {22272242} } 