Wildlife Conservation Society: “What happens to a dispersing animal after it enters a new population is unknown. Does it integrate and successfully reproduce, or find territories and mate?”. This question gains importance in highlighting current gaps in our understanding of animal dispersal.
Connectivity is a critical factor. However, little is known about the influence of behaviour of dispersing animals and their fate after they immigrate into new populations. Lack of attractiveness to potential mates in dispersers can reduce real landscape connectivity, according to a new study published by scientists Dr Divya Vasudev at the Wildlife Conservation Society, India Program and Prof Rob Fletcher at the University of Florida, USA in the prestigious journal Ecological Modeling.
Using individual-based simulations, the authors modelled mate choice and dispersal in animals across multiple generations. They showed that even when animals could disperse freely through contiguous habitats, mate choice alone could lead to isolated populations if females avoided mating with dispersers. Thus mate choice issue could further accentuate negative consequences of habitat fragmentation, resulting in unexpected occurrences of isolated populations based on habitat maps and apparent ‘corridors’.
The huge costs of traversing across large landscapes can make dispersers unattractive as potential mates. Females may also look for a degree of familiarity in mates. For populations that have adapted to local environmental conditions, familiarity relates directly to an ability to survive. On the other hand, due to inbreeding and associated costs of mating with close relatives, females may actually prefer mating with dispersers, according to this study. Mate choice by females can determine how dispersing animals can join new populations, the study stated.
The published study by WCS scientist Dr Divya Vasudev and Prof Rob Fletcher from University of Florida throws up a number of questions on the ecological constraints to habitat connectivity, and highlights the need for further research. “This study is a milestone in applying advanced quantitative methods to practical conservation issues relevant to India,” said Dr Ullas Karanth, Director for Science Asia, for WCS