Landscape‐scale effects of fire on bird assemblages: does pyrodiversity beget biodiversity?

Abstract

Aim A common strategy for conserving biodiversity in fire‐prone environments is to maintain a diversity of post‐fire age classes at the landscape scale, under the assumption that ‘pyrodiversity begets biodiversity’. Another strategy is to maintain extensive areas of a particular seral state regarded as vital for the persistence of threatened species, under the assumption that this will also cater for the habitat needs of other species. We investigated the likely effects of these strategies on bird assemblages in tree mallee vegetation, characterized by multi‐stemmed Eucalyptus species, where both strategies are currently employed. Location The semi‐arid Murray Mallee region of south‐eastern Australia. Methods We systematically surveyed birds in 26 landscapes (each 4‐km diameter), selected to represent gradients in the diversity of fire age classes and the proportion of older vegetation (> 35 years since fire). Additional variables were measured to represent underlying vegetation‐ or fire‐mediated properties of the landscape, as well as its biogeographic context. We used an information‐theoretic approach to investigate the relationships between these predictor variables and the species richness of birds (total species, threatened species and rare species). Results Species richness of birds was not strongly associated with fire‐mediated heterogeneity. Species richness was associated with increasing amounts of older vegetation in landscapes, but not with the proportion of recently burned vegetation in landscapes. Main conclusions The preference of many mallee birds for older vegetation highlights the risk of a blanket application of the ‘pyrodiversity begets biodiversity’ paradigm. If application of this paradigm involved converting large areas from long unburned to recently burned vegetation to increase fire‐mediated heterogeneity in tree mallee landscapes, our findings suggest that this could threaten birds. This research highlights the value of adopting a landscape‐scale perspective when evaluating the utility of fire‐management strategies intended to benefit biodiversity.

Interactions between Forest Resource Management and Landscape Structure

“…Many studies have shown that spatial patterns of landscape cover can have profound effects on biota (e.g., [16,37,38]). However, as outlined above, forest landscapes worldwide are increasingly subject to rapid transformation [31,39••], with novel combinations of drivers producing novel patterns of landscape structure [12•].…”

“…Yet, how such combinations of disturbances and novel spatial and temporal patterns of landscape cover affect biodiversity and key ecological processes remains poorly understood. Moreover, work on interactions between logging, landscape structure, and fire remains highly contentious and controversial [13][14][15][16]. Given this, considerable empirical work is required to develop a strong body of scientific evidence that can help resolve debates about relationships between the type and spatial pattern of logging, landscape structure, and responses of biodiversity and key ecosystem processes.…”

Effects of habitat extent and forest disturbance on bird communities in lowland nepal

“…Landscapes with more forest cover support a larger species pool (Hu et al 2012, Taylor et al 2012) through both sampling effects (Wiens 1992, Whittaker andFernández-Palacios 2007) and because a greater forest extent offers habitat diversity (Radford et al 2005, Maron et al 2012. Several empirical studies have shown that sites in landscapes with more forest support higher densities of reptiles (McAlpine et al 2015), greater species richness and abundance of birds (Villard et al 1999, Mortelliti et al 2010, Martensen et al 2012, Taylor et al 2012, and greater richness of small mammals (McAlpine et al 2006, Estavillo et al 2013). These findings suggest that a wide range of forest-dependent faunal communities can persist even in modified landscapes, as long as adequate forest cover is retained (Radford et al 2005, Ochoa-Quintero et al 2015.…”

“…Landscapes with more forest cover support a larger species pool (Radford and Bennett 2007, Haslem and Bennett 2008, Taylor et al 2012) through both sampling effects, and because a greater extent of forest cover in landscapes offers habitat diversity (Radford et al 2005, Maron et al 2012, and can serve source habitats for range of species (Pulliam 1988). Birds are a mobile taxon, and their presence at a particular site does not necessarily mean they are resident, nor that they solely use the resources within that site.…”

“…More recently, key empirical studies (e.g. Radford and Bennett 2007, Pardini et al 2010, Maron et al 2012, Taylor et al 2012, Bennett et al 2014, Ochoa-Quintero et al 2015 have begun to focus on landscape-scale sampling, examining how the assemblages of entire landscapes respond to landscape characteristics in Australia. My results are consistent with several of these recent studies for birds that showed strong positive relationships between species richness and the extent of forest cover in the landscape (Radford et al 2005, Maron et al 2012, Ochoa-Quintero et al 2015.…”