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POPULATION VIABILITY AND REINTRODUCTION STRATEGIES: A SPATIALLY EXPLICIT LANDSCAPE‐LEVEL APPROACH
Author(s) -
Münzbergová Zuzana,
Mildén Mikael,
Ehrlén Johan,
Herben Tomáš
Publication year - 2005
Publication title -
ecological applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.864
H-Index - 213
eISSN - 1939-5582
pISSN - 1051-0761
DOI - 10.1890/04-1464
Subject(s) - habitat , ecology , extinction (optical mineralogy) , metapopulation , population , grassland , colonization , biology , habitat destruction , biological dispersal , paleontology , demography , sociology
The effect of habitat destruction on the likelihood of species survival is often estimated based on the assumption that colonization and extinctions are in balance. This assumption is not sustainable in species where the dynamics of colonization and extinctions is slow in relation to landscape changes, such as in most plants. Here we use an alternative approach, a realistic, dynamic landscape‐level model that does not rely on this assumption. It enables estimation of the effect of habitat destruction using field data on the biology of a species and on real landscape structure. Because our approach relies on direct comparisons of changes in population size and survival probability due to habitat changes, it can be easily extended to other conservation questions, such as assessing the effects of events causing the extinction of populations but allowing for recolonization, or identifying optimal reintroduction strategies. We applied this method to a perennial herb, Succisa pratensis , that is a typical grassland species. We combined detailed demographic data with information on the spatial distribution of suitable habitats to model species dynamics in the landscape under different scenarios. The results show that habitat destruction alone has little effect on regional survival. However, the effect of habitat destruction increases when combined with factors causing extinctions of the existing populations that are expected to play a significant role in the study system. Our results further show that an optimal reintroduction strategy at the landscape level depends on the number of available seeds. The approach presented here was designed for studying systems where species colonization–extinction dynamics is slow compared with landscape changes. Such time lags and nonequilibrium dynamics have been suggested to be important features of many ecosystems and life forms, and this approach is thus likely to be useful for a wide range of future studies. The approach also allows the estimation of short‐term effects of habitat destruction, i.e., situations that are nonequilibrium by definition. This is never possible with equilibrium models, giving the model a wide applicability for all types of organisms.