Scale‐dependent effects of isolation on seasonal patch colonisation by two Neotropical freshwater fishes

Ecology of Freshwater Fish
By: , and 

Links

Abstract

The metapopulation paradigm has been central to improve the conservation and management of natural populations. However, despite the large number of studies on metapopulation dynamics, the overall support for the relationships on which the paradigm is based has not been strong. Here, we studied the occupancy dynamics of two Neotropical fishes (i.e., Pimelodella gracilis and Leporinus friderici) to investigate two fundamental premises of the metapopulation paradigm, that is, that isolation and area/habitat quality affect colonisation and extinction probabilities in predictable ways. In order to do this, we used a modification of occupancy models that allows modelling the probability of a site's occupancy as a function of the occupancy of its neighbourhood. We found a weak positive effect of neighbourhood occupancy on Pgracilis colonisation, which is consistent with the propagule rain metapopulation, that is, colonists arriving from outside the studied system. However, we found a strong negative neighbourhood effect on extinction probability, suggesting that declining populations from stream sections are rescued from extinction by neighbouring patches. In contrast, the effect of neighbourhood occupancy on the metapopulation dynamics of L. friderici was in the opposite direction, affecting positively colonisation but not affecting extinction rates, which is consistent with the classical metapopulation model. In addition, the occupancy dynamics of both species were affected by water velocity. To our knowledge, this is the first study to link directly dispersal to local population dynamics in Neotropical fishes, and one of the few studies doing inferences on spatial population dynamics based on direct estimates of neighbourhood occupancy.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Scale‐dependent effects of isolation on seasonal patch colonisation by two Neotropical freshwater fishes
Series title Ecology of Freshwater Fish
DOI 10.1111/eff.12452
Volume 28
Issue 2
Year Published 2019
Language English
Publisher Wiley
Contributing office(s) Patuxent Wildlife Research Center
Description 11 p.
First page 274
Last page 284