Evaluating feedback dynamics between poaching and population with an application to Indian tigers

A cornerstone of conservation policy for endangered species subject to illegal harvest involves estimating their population and offtake numbers. Census enumerations are expensive to conduct on nationwide scales, especially in resource-constrained countries housing such species. Resource and data limitations necessitate the estimation of population counts. The effect of poaching on species recruitment is often ignored in scientific population projections. Estimation of population counts should account for the interactive feedback between harvest and recruitment. Data on tiger population sizes and poaching from 51 reserves in India between 1994 and 2022 were obtained to calibrate a coupled ecological-economic model of tiger population dynamics and poaching. Cobb-Douglas harvest functions with differing degrees of concavity and scale economies are used to characterize the economics of poaching. Population dynamics are evaluated using exponential and critical depensation growth functions. The predictive abilities of linked models and their parameter parsimony are evaluated using information criteria. Poaching is shown to substantially affect recruitment dynamics and is best characterized by a Schaefer function coupled with critical depensation growth. This paper provides a novel perspective of the interaction between tiger poaching and population dynamics in India. A systematic understanding of coupled ecological-economic processes would improve the management of high-value endangered species.

Automated summary

This study models and analyzes the population dynamics of tigers and poaching in 51 reserves in India. It finds that poaching has a significant impact on tiger recruitment dynamics, and the use of a Schaefer function coupled with critical depensation growth best describes this relationship. This study provides a novel perspective on the interaction between tiger poaching and population dynamics in India.