Habitat fragmentation and biodiversity collapse in neutral communities

Models of habitat fragmentation have mainly explored the effects on a few-species ecologies or on a hierarchical community of competitors. These models reveal that, under different conditions, ecosystem response can involve sharp changes when some given thresholds are reached. However, perturbations, recruitment limitation and other causes may prevent competitive hierarchies from actually operating in natural conditions: the process of competitive exclusion underlying hierarchies could not be a determinant factor structuring communities. Here we explore both spatially-implicit and spatially-explicit metapopulation models for a competitive community, where the colonization-extinction dynamics takes place through neutral interactions. Here species interactions are not hierarchical at all but are somehow ecologically equivalent and just compete for space and resources through recruitment limitation. Our analysis shows the existence of a common destruction threshold for all species: whenever habitat loss reaches certain value a sudden biodiversity collapse takes place. Furthermore, the model is able to reproduce species-rank distributions and its spatially explicit counterpart predicts also species–area laws obtained from recent studies on rainforest plots. It is also discussed the relevance of percolation thresholds in limiting diversity once the landscape is broken into many patches. © 2004 Elsevier B.V. All rights reserved.

[1]  Ricard V. Solé,et al.  Phase transitions and complex systems: Simple, nonlinear models capture complex systems at the edge of chaos , 1996, Complex..

[2]  David Alonso,et al.  Random Walks, Fractals and the Origins of Rainforest Diversity , 1998, Adv. Complex Syst..

[3]  Hal Caswell,et al.  Habitat fragmentation and extinction thresholds on fractal landscapes , 1999 .

[4]  P. Crowley,et al.  Trade‐offs and Spatial Life‐History Strategies in Classical Metapopulations , 2002, The American Naturalist.

[5]  Ricard V. Solé,et al.  Habitat Fragmentation and Extinction Thresholds in Spatially Explicit Models , 1996 .

[6]  Claudia Neuhauser,et al.  Ergodic theorems for the multitype contact process , 1992 .

[7]  R. Solé,et al.  Scaling in a network model of a multispecies ecosystem , 2000 .

[8]  Rick Durrett,et al.  Stochastic Spatial Models , 1999, SIAM Rev..

[9]  A Barkai,et al.  Predator-Prey Role Reversal in a Marine Benthic Ecosystem , 1988, Science.

[10]  Solé,et al.  Effects of habitat destruction in a prey-predator metapopulation model , 1998, Journal of theoretical biology.

[11]  W. L..  The Balance of Nature , 1870, Nature.

[12]  Peter Kareiva,et al.  Spatial ecology : the role of space in population dynamics and interspecific interactions , 1998 .

[13]  J. G. Skellam.  Random dispersal in theoretical populations , 1951, Biometrika.

[14]  Stephen J. Wright,et al.  Light-Gap disturbances, recruitment limitation, and tree diversity in a neotropical forest , 1999, Science.

[15]  Steinar Engen,et al.  POPULATION DYNAMIC MODELS GENERATING SPECIES ABUNDANCE DISTRIBUTIONS OF THE GAMMA TYPE , 1996 .

[16]  L. Stone.  Biodiversity and habitat destruction: a comparative study of model forest and coral reef ecosystems , 1995, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[17]  R. Levins.  Some Demographic and Genetic Consequences of Environmental Heterogeneity for Biological Control , 1969 .

[18]  R. Solé,et al.  Mean-field stochastic theory for species-rich assembled communities. , 2000, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics.

[19]  D. Tilman.  Resource competition and community structure. , 1983, Monographs in population biology.

[20]  R. Fisher,et al.  The Relation Between the Number of Species and the Number of Individuals in a Random Sample of an Animal Population , 1943 .

[21]  D. Tilman.  Competition and Biodiversity in Spatially Structured Habitats , 1994 .

[22]  G. E. Hutchinson,et al.  The Loves of the Card Index Cards , 1951 .

[23]  S. Levin,et al.  Comparing Classical Community Models: Theoretical Consequences for Patterns of Diversity , 2002, The American Naturalist.

[24]  L. Milne,et al.  The Balance of Nature , 1953, Oryx.

[25]  Ricard V Solé,et al.  Self-organized instability in complex ecosystems. , 2002, Philosophical transactions of the Royal Society of London. Series B, Biological sciences.

[26]  J. L. Gittleman,et al.  The Future of Biodiversity , 1995, Science.

[27]  M. Nowak,et al.  Habitat destruction and the extinction debt , 1994, Nature.

[28]  N. Brokaw,et al.  Niche versus chance and tree diversity in forest gaps. , 2000, Trends in ecology & evolution.

[29]  Jorge X Velasco-Hernández,et al.  Extinction Thresholds and Metapopulation Persistence in Dynamic Landscapes , 2000, The American Naturalist.

[30]  C. Dytham.  Habitat destruction and competitive coexistence: a cellular model. Commentary , 1994 .

[31]  Uno Wennergren,et al.  Connecting landscape patterns to ecosystem and population processes , 1995, Nature.

[32]  D. Tilman,et al.  Competition in spatial habitats , 1997 .

[33]  G. E. Hutchinson,et al.  Copepodology for the Onithologist , 1951 .

[34]  Salvador Pueyo Puntí.  Irreversibility and Criticality in the Biosphere , 2003 .

[35]  David Gimenez.  The stochastic nature of ecological interactions , 2004 .

[36]  R. Durrett,et al.  The Importance of Being Discrete (and Spatial) , 1994 .

[37]  D. Tilman.  Diversity by Default , 1999, Science.

[38]  William H. Press,et al.  Numerical recipes in C , 2002 .

[39]  J. Diamond,et al.  Ecology and Evolution of Communities , 1976, Nature.

[40]  R. Macarthur,et al.  The Theory of Island Biogeography , 1969 .

[41]  C. Dytham.  The effect of habitat destruction pattern on species persistence : a cellular model , 1995 .

[42]  Jordi Bascompte,et al.  Phase transitions and complex systems , 1995 .

[43]  R. Fisher.  193: A Theoretical Distribution for the Apparent Abundance of Different Species. , 1943 .

[44]  A. McKane,et al.  Extinction dynamics in mainland-island metapopulations: An N-patch stochastic model , 2002, Bulletin of mathematical biology.

[45]  R. Solé,et al.  The DivGame Simulator: a stochastic cellular automata model of rainforest dynamics , 2000 .