Effects of fire frequency on savanna butterfly diversity and composition: A preliminary study

Elie Gaget,Catherine L Parr,Clélia Sirami

doi:10.4102/koedoe.v62i1.1617

Abstract

Fire plays a major role in many biomes, is widely used as a management tool and is likely to be affected by climate change. For effective conservation management, it is essential to understand how fire regimes affect different taxa, yet responses of invertebrates are particularly poorly documented. We tested how different fire frequencies influence savanna butterfly diversity and composition by using a long-term savanna fire experiment initiated in 1954 in the Kruger National Park (South Africa). We compared butterfly abundance, species richness and community composition across three fire frequencies: high (burnt annually), medium (burnt triennially) and low (burnt twice in 60 years). Plots with high fire frequency hosted higher abundance than medium- or low-frequency plots. Fire frequencies did not affect species richness, but they led to distinct communities of butterflies. Our findings suggest that, in view of the three fire frequencies tested, a spatial diversity of fire frequencies may increase butterfly diversity at the landscape level in wet savannas. Managers may need to promote a greater diversity of fire frequencies by increasing fire frequency in some areas to provide habitat for species requiring high fire frequency, and by decreasing fire frequency in a large proportion of the landscape to provide fire refuges. This study provides new insights for butterfly conservation in savannas and highlights several knowledge gaps, which further studies should address for insect responses to be given adequate consideration in fire management strategies.Conservation implications: A spatial diversity of fire frequencies may increase butterfly diversity. Managers may need to promote a greater diversity of fire frequencies by increasing fire frequency in some areas to provide habitat for species requiring high fire frequency, and by decreasing fire frequency in other areas to provide fire refuges.

Highlights

Fire is a frequent and widespread disturbance in many biomes (Pausas & Keeley 2009) and shapes landscapes by modifying vegetation structure and composition (Bond & Keeley 2005)
The recent increase in large uncontrolled fire incidences and predictions indicating that the frequency of high-intensity fires will increase in the future as a result of climate change (Pechony & Shindell 2010) have triggered growing concerns about the impacts of changes in long-term fire regimes
This study represents a first assessment on the effect of differences in long-term fire frequencies on butterfly communities in wet African savannas

Summary

Introduction

Fire is a frequent and widespread disturbance in many biomes (Pausas & Keeley 2009) and shapes landscapes by modifying vegetation structure and composition (Bond & Keeley 2005). Fire has become one of the primary tools for biodiversity conservation (Andersen et al 1998; Parr & Chown 2003). Fire management practices for biodiversity conservation are often based on limited information, usually focussing on the response of plant communities in short-term studies or natural experiments by using space-for-time substitution (Driscoll et al 2010). Data on the longterm ecological response of multiple taxa to fire regimes are crucial to design appropriate fire management strategies for biodiversity conservation (Andersen et al 1998). Despite the fact that invertebrates represent the largest component of global biodiversity and ecosystem functioning (Lavelle et al 2006; Losey & Vaughan 2006), they are relatively poorly studied in fire ecology research (New et al 2010; Parr & Chown 2003)

Methods

Results

Conclusion