Burning savanna for avian species richness and functional diversity

Abstract

Prescribed fire is used throughout fire-prone landscapes to conserve biodiversity. Current best practice in managing savanna systems advocates methods based on the assumption that increased fire-mediated landscape heterogeneity (pyrodiversity) will promote biodiversity. However, considerable knowledge gaps remain in our understanding of how savanna wildlife responds to the composition and configuration of pyrodiverse landscapes. The effects of pyrodiversity on functional diversity have rarely been quantified and assessing this relationship at a landscape scale that is commensurate with fire management is important for understanding mechanisms underlying ecosystem resilience. Here, we assess the impact of spatiotemporal variation in a long-term fire regime on avian diversity in North West Province, South Africa. We examined the relationship between (1) species richness, (2) three indices of functional diversity (i.e., functional richness, functional evenness, and functional dispersion) and four measures of pyrodiversity, the spatial extents of fire age classes, and habitat type at the landscape scale. We then used null models to assess differences between observed and expected functional diversity. We found that the proportion of newly burned (<1-yr post-fire), old, unburned (≥10 yr post-fire), and woodland habitat on the landscape predicted species and functional richness. Species richness also increased with the degree of edge contrast between patches of varying fire age, while functional dispersion increased with the degree of patch shape complexity. Lower than expected levels of functional richness suggest that habitat filtering is occurring, resulting in functional redundancy across our study sites. We demonstrate that evaluating functional diversity and redundancy is an important component of conservation planning as they may contribute to previously reported fire resilience. Our findings suggest that it is the type and configuration, rather than the diversity, of fire patches on the landscape that promote avian diversity and conserve ecological functions. A management approach is needed that includes significant coverage of adjacent newly burned and older, unburned savanna habitat; the latter, in particular, is inadequately represented under current burning practices.

Variations in Avian Species and Functional Diversity in Different Habitat Types in a Vulnerable Savannah Ecosystem in Ghana

“…Tis could have led to a loss in breeding grounds, food, and cover, thereby restricting birds to the riparian forest and woodland habitats. We also observed higher numbers of post-fre specialists (mostly northern carmine bee-eater and some raptors like grasshoppers and lizard buzzards, among others) and other generalist species, suggesting that many savanna species can tolerate and utilize burned areas [85]. Tough the attraction of generalist species to the burnt site could lead to increase in avian species richness [86], our study found otherwise.…”

“…Tough the attraction of generalist species to the burnt site could lead to increase in avian species richness [86], our study found otherwise. In contrast, Docherty et al [85] found a positive association between species richness and newly burned habitats in the Pilanesberg National Park, South Africa [85].…”

Interpreting Smoke Signals: Fire Ecology and Land Management for Four Federally Listed Birds

“…With several years of added experience, fire managers may be able to use these models to fine-tune the outcome a prescribed fire is likely to have on groundforaging species. Greater post-burn heterogeneity and the type and configuration of fire patches promote avian diversity in other fire-maintained systems (Docherty et al, 2020).…”

Land-use policies overcome fire suppression effects on functional diversity in a fire-prone, abandoned mountain area

“…However, these agricultural policies have been proved rather ine cient, especially in Southern European countries, which highlights the need for a greener EU farm policy (Pe'er et al The complex interactions between re and vegetation dynamics make their impacts on biodiversity hardto-predict, especially under alternative land-use and/or re-suppression policies. Previous studies have found that policies promoting HNV farmlands can be effective solutions for biodiversity conservation and wild re mitigation in areas largely affected by land abandonment (Aquilué et Species richness has been widely used as a measure of biodiversity and its response to different environmental factors, such as land-use change and re effects (Docherty et al 2020). Nonetheless, the importance of measuring the effects of ecological disturbances on functional diversity has been progressively mentioned as pivotal to assess the impacts on the distribution and abundance of species traits that contribute to the community resilience and ecosystem functioning (Wood et al 2015;Riemann et al 2017).…”