Interaction between Allee effects caused by organism-environment feedback and by other ecological mechanisms.

Lijuan Qin,Wanxiong Wang,Feng Zhang,Weixin Song,Gui-Quan Sun

doi:10.1371/journal.pone.0174141

Abstract

Understanding Allee effect has crucial importance for ecological conservation and management because it is strongly related to population extinction. Due to various ecological mechanisms accounting for Allee effect, it is necessary to study the influence of multiple Allee effects on the dynamics and persistence of population. We here focus on organism-environment feedback which can incur strong, weak, and fatal Allee effect (AE-by-OEF), and further examine their interaction with the Allee effects caused by other ecological mechanisms (AE-by-OM). The results show that multiple Allee effects largely increase the extinction risk of population either due to the enlargement of Allee threshold or the change of inherent characteristic of Allee effect, and such an increase will be enhanced dramatically with increasing the strength of individual Allee effects. Our simulations explicitly considering spatial structure also demonstrate that local interaction among habitat patches can greatly mitigate such superimposed Allee effects as well as individual Allee effect. This implies that spatially structurized habitat could play an important role in ecological conservation and management.

Highlights

Allee effect, the positive relationship between per capita growth rate and population density at low population density [1], has received considerable attention in ecology and conservation because it is directly related to population extinction [2,3,4] and can incur complicated spatial pattern [5, 6]
Due to various ecological mechanisms leading to Allee effect, it is necessary to study the influence of multiple Allee effects on population dynamics and persistence
Organism-environment positive feedback will individually incur Allee effect (i.e. AE-by-OEF) when λ > (μ + d)2 / d, of which inherent characteristic depends on model parameters (Eqs 1 or 2 with a = 0)

Summary

Introduction

The positive relationship between per capita growth rate (individual’s fitness) and population density at low population density [1], has received considerable attention in ecology and conservation because it is directly related to population extinction [2,3,4] and can incur complicated spatial pattern [5, 6]. Multiple Allee efffects organism-environment positive feedback when Allee effect caused by other ecological mechanism is involved in .

Results

Conclusion