of Marine Ecology, Tjärnö Marine Biological Laboratory, SE-452 96 Strömstad, Sweden'
author:
- David Kleinhans
- 'Per R. Jonsson'
title: On the impact of dispersal asymmetry on metapopulation persistence
---

Connectivity matrix, dispersal network, symmetry, metapopulation viability.

Introduction
============

Many species are structured in space with dispersal and migration connecting local populations into metapopulations [@Levins69; @Hanski97]. The fundamental dynamics of metapopulations are determined by local extinction, dispersal from the local populations, and colonisation success leading to the establishment of new sub-populations [@Levins69]. Metapopulation dynamics may determine a range of ecological and evolutionary aspects including population size [@Gyllenberg92], persistence [@Roy05], spatial distribution [@Roy08], epidemic spread [@McCallum02; @Davis08], gene flow [@Sultan02], and local adaptation [e.g. @Hanski98; @Joshi01]. Much interest has focused on the effect of the spatial structure of metapopulations and how local populations are connected through dispersal. Connectivity among subpopulations is also increasingly emphasized in management and conservation, e.g. to prevent fragmentation of landscapes [@Crooks] and in the design of protected areas and nature reserves [@vanTeeffelen06].

Early models [e.g. @Levins69; @Hanski] assumed identical dispersal probability among habitat patches. The initial focus of spatially explicit metapopulation theory was to explore processes that generate spatial patterns in homogeneous landscapes [@Hanski02; @Malchow]. Later, spatially 