The long-term effect of over-supplementation on recovered populations: why restraint is a virtue

Paweł Adamski,Adam M Ćmiel

doi:10.1017/s0030605321000296

Abstract

AbstractWe present a long-term analysis of the results of the Apollo butterflyParnassius apollorecovery project in the Pieniny National Park, southern Poland, using a classical population ecology model. Six possible theoretical models of changes in population abundance were constructed and their predictions compared with current data. Models that did not take into account supplementation with captive-reared individuals provided the best fit to the population growth pattern during recovery. This was probably because of the introduction of captive-reared specimens to sites while habitat reconstruction was taking place. In addition, we provide data supporting the hypothesis that a significant reduction in the habitat's carrying capacity occurred during the restoration project, probably as a result of the population being over-supplemented with captive-reared individuals. Our analysis shows that for a recovery project to be successful, captive breeding and habitat restoration should be properly coordinated.

Highlights

Population recovery programmes using captive-reared individuals make an important contribution to conservation (Saint-Jailme, ; Seddon et al, ; Armstrong & Seddon, ; Zając et al, )
Six theoretical population growth scenarios were modelled: Scenario (WO K ): not including captive-reared individuals; carrying capacity K constant; Scenario (WO + shift): not including captivereared individuals; carrying capacity reduced from K to K ; Scenario (WO K ): not including captive-reared individuals; carrying capacity K constant; Scenario (CI K ): including captive-reared individuals; carrying capacity K constant; Scenario (CI + shift): including captive-reared individuals; carrying capacity reduced from K to K ; Scenario (CI K ): including captive-reared individuals; carrying capacity K constant
The results suggest that of the six population growth scenarios, the one involving a substantial reduction in habitat carrying capacity best fits the data

Summary

Introduction

Population recovery programmes using captive-reared individuals make an important contribution to conservation (Saint-Jailme, ; Seddon et al, ; Armstrong & Seddon, ; Zając et al, ). Before the late s a significant number of such projects failed (IUCN, ; Griffith et al, ; Witkowski et al, ; Adamski & Witkowski, a; Fisher & Lindenmayer, ; Suding et al, ; Seddon et al, ; Moseby et al, ) or relied on constant replenishment with captive-reared individuals (Young et al, ; Pedrono et al, ). The biological or ecological constraints of the species being restored Such constraints may relate to the genetic pool and local adaptations (Sarrazin & Barbault, ; Moritz, ; Hedrick & Kalinowski, ; Baums, ) or to difficulties ensuing from recovery projects being carried out in highly modified ecosystems that had already achieved a resilient alternative state (Bakker & Berendse, ; Beisner et al, ; Suding et al, ; Young et al, ). For animals with highly developed nervous systems, distress or behavioural reactions may affect the outcome of conservation activities, and the implementation of stress-reducing release strategies has been widely discussed (Griffith et al, ; Wolf et al, ; Moseby et al, )

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Results

Conclusion