Interactive effects of fluctuating environments and dispersal on total population size

The effect of dispersal in a fragmented habitat is often studied using temporally homogeneous metapopulation models. However, natural environments are characterized by temporal heterogeneity, where factors like resource availability and temperature fluctuate over time. This study extends the classic discrete-time two-patch model by incorporating temporal heterogeneity in model parameters to investigate the effect of environmental fluctuations on total biomass. Our analysis reveals that while fluctuations preserve some established principles, such as the always-beneficial effect of connecting two source patches with identical intraspecific competition, they also generate novel and unexpected dynamics. We show that fluctuations generate new response patterns of total biomass to an increase of dispersal. Furthermore, we demonstrate that fluctuations can alter the qualitative response of connectivity, creating situations where connecting two patches, each of which would suffer from connectivity in a static environment, can become beneficial under periodic conditions. These results underscore the critical importance of incorporating temporal heterogeneity to accurately predict the consequences of habitat fragmentation and to design effective conservation strategies.