Premium
Dispersal in heterogeneous habitats: thresholds, spatial scales, and approximate rates of spread
Author(s) -
Dewhirst Sebastian,
Lutscher Frithjof
Publication year - 2009
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.1890/08-0115.1
Subject(s) - allee effect , biological dispersal , fragmentation (computing) , ecology , habitat fragmentation , population , habitat , extinction (optical mineralogy) , spatial heterogeneity , statistical physics , geography , mathematics , biology , physics , demography , paleontology , sociology
What is the effect of landscape heterogeneity on the spread rate of populations? Several spatially explicit simulation models address this question for particular cases and find qualitative insights (e.g., extinction thresholds) but no quantitative relationships. We use a time‐discrete analytic model and find general quantitative relationships for the invasion threshold, i.e., the minimal percentage of suitable habitat required for population spread. We investigate how, on the relevant spatial scales, this threshold depends on the relationship between dispersal ability and fragmentation level. The invasion threshold increases with fragmentation level when there is no Allee effect, but it decreases with fragmentation in the presence of an Allee effect. We obtain simple formulas for the approximate spread rate of a population in heterogeneous landscapes from averaging techniques. Comparison with spatially explicit simulations shows an excellent agreement between approximate and true values. We apply our results to the spread of trees and give some implications for the control of invasive species.