Modelling the impact of habitat fragmentation on brown trout population dynamics

Abstract

Habitat fragmentation caused by the presence of insurmountable obstacles in a fish population has implications in its temporal dynamics, mainly affecting the population viability thresholds. Thus, an artificially fragmented population needs a greater population density to ensure its long-term viability. Based on a theta-logistic population dynamics model to which a population viability threshold effect has been added, the concept of resilience is defined by two factors: resistance and recovery ability. Resistance depends on the difference between population viability threshold and carrying capacity. This work analyses the sensitivity of and the consequences on the parameter resilience to different locations and conditions of an insurmountable obstacle fragmenting a native population of brown trout.