Exploring the implications of recreational disturbance on an endangered butterfly using a novel modelling approach

Abstract

Site and wildlife managers globally are under increasing pressure to implement management strategies that address the negative implications of outdoor recreational activities on wildlife. For many rare and isolated species any anthropogenic activities that cause disturbance could potentially be detrimental to existing populations. Understanding how non-consumptive recreation can influence a species may therefore be critical to its preservation. We developed a novel approach to specifically address this need. Using a combination of field surveys and simulation modelling exercises, we (1) explored the responses of endangered Karner blue butterflies (Lycaeides melissa samuelis) to recreation, (2) assessed whether such responses influenced oviposition rate and/or host plant choice and (3) tested alternative management strategies that could alleviate the negative impacts of recreation. Our field surveys confirmed that Karner blues were sensitive to recreational disturbance. Butterflies flushed at similar speeds and distances from recreationists (2.2 m at 0.17 m/s), as they would from natural threats, such as predators (2.2 m at 0.19 m/s). Incorporating female response parameters into a simulation model revealed that regular disturbance could reduce egg laying potential and significantly restrict host plant choice, which in turn, could impact the butterfly’s population dynamics. However, we established that it was possible to effectively offset the implications of recreational disturbance using our simulation modelling approach. For example, extending Karner blue breeding habitat from trails and other public rights of way has the potential to alleviate such disturbance. Our study demonstrates that the potential impact of recreation on species of conservation concern should not be overlooked.