Synopsis:
This study aimed to independently examine the effects of varying amounts and configurations of habitat at a landscape scale, with particular attention to critical persistence thresholds. A discrete reaction-diffusion model was used to estimate long-term equilibrium population persistence of a hypothetical species in a patchy landscape. When examined over a broad range of habitat amount and arrangements, population size was largely determined by the proportion of habitat (amount) in a landscape. However, when habitat coverage dropped below 30-50%, population response deviated, coinciding with a persistence threshold. Species persistence declined rapidly at this threshold range (50% for low degrees of aggregation, 40% for high and moderate degrees of aggregation). At this point, habitat arrangement explained a greater amount of variation in population size than did habitat amount.
Conclusions:
When examined over a broad range of habitat amount and arrangements, population size was largely determined by the proportion of habitat in a landscape. However, when habitat coverage dropped below 30-50%, population persistence reached a critical threshold and declined rapidly. After this point, habitat arrangement explained variation in population size more than habitat amount.
Thresholds/Learnings:
When habitat coverage dropped below 30-50%, population persistence reached a critical threshold. Species persistence declined rapidly at this threshold range (50% for low degrees of aggregation, 40% for high and moderate degrees of aggregation)
