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Scale‐dependent role of demography and dispersal on the distribution of populations in heterogeneous landscapes
Author(s) -
Martin Benjamin T.,
Czesny Sergiusz,
Wahl David H.,
Grimm Volker
Publication year - 2016
Publication title -
oikos
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.672
H-Index - 179
eISSN - 1600-0706
pISSN - 0030-1299
DOI - 10.1111/oik.02345
Subject(s) - biological dispersal , ideal free distribution , ecology , habitat , population , distribution (mathematics) , scale (ratio) , field (mathematics) , geography , biology , mathematics , demography , cartography , sociology , mathematical analysis , pure mathematics
Both dispersal and local demographic processes determine a population's distribution among habitats of varying quality, yet most theory, experiments, and field studies have focused on the former. We use a generic model to show how both processes contribute to a population's distribution, and how the relative importance of each mechanism depends on scale. In contrast to studies only considering habitat‐dependent dispersal, we show that predictions of ideal free distribution (IFD) theory are relevant even at landscape scales, where the assumptions of IFD theory are violated. This is because scales that inhibit one process, promote the other's ability to drive populations to the IFD. Furthermore, because multiple processes can generate IFDs, the pattern alone does not specify a causal mechanism. This is important because populations with IFDs generated by dispersal or demography respond much differently to shifts in resource distributions.