Is the reptile community affected by Eucalyptus wandoo tree condition?

Abstract

Context. Large portions of the world's forests and woodlands are currently affected by declines in canopy condition of dominant tree species; however, the effects of these declines on faunal communities are largely unknown. Eucalyptus wandoo woodlands in the Southwest region of Western Australia have demonstrated declines in condition since the early 1990s. Such declines in tree condition can result in reduced understorey vegetation, increased leaf-litter cover and coarse woody debris, potentially altering the habitat and resource available to reptiles. Prescribed fire events, another mechanism of habitat change for reptiles, are a common occurrence in these woodlands.Aims. The present research investigated whether reptile communities were influenced by E. wandoo tree condition, and the changes in the habitat associated with E. wandoo decline.Methods. Reptile trapping was conducted at 24 E. wandoo-dominated sites (of varying condition) in Dryandra State Forest and Wandoo Conservation Park, Western Australia.Overall, reptile abundance, species richness and individual reptile species abundances (only those species captured in sufficient numbers for analysis) were compared with a range of habitat characteristics that are likely to be altered by changes in E. wandoo tree condition.Key results. Overall, higher reptile abundance and species richness were observed at sites with longer time since fire and more site litter cover. There was also a greater abundance and diversity of reptiles at sites where E. wandoo trees exhibited fewer symptoms of tree decline.Similar analyses for the five most common skink species indicated species-specific relationships with tree-condition measures, time since last fire, site litter cover, distance to drift fence from E. wandoo trees, understorey vegetation density and the density of coarse woody debris.Conclusions. Abundance and species diversity of the reptile communities in E. wandoo woodlands were strongly related to time since last fire, E. wandoo tree condition and habitat characteristics such as site litter cover and the density of coarse woody debris.Implications. Decline in the condition of E. wandoo trees and the fire events in E. wandoo woodlands are both mechanisms of change correlated with reptile habitat and resources.Future management of E. wandoo woodlands may include reducing prescribed fire events in areas demonstrating symptoms of tree decline, to conserve reptile abundance and species richness. TOC AbstractEucalyptus wandoo woodlands of Western Australia are one of the many forests and woodlands declining worldwide. Live capture trapping of reptile communities in E. wandoo woodlands determined that reptile abundance and species richness was higher in areas exhibiting fewer E. wandoo decline symptoms, more site leaf litter and a longer time since fire. Management of E. wandoo woodlands in the future should consider reducing the occurrence of fire events, particularly in areas undergoing a decline in condition.Additional keywords: fire history, microhabitat, skinks, W...

Inferring drought and heat sensitivity across a Mediterranean forest region in southwest Western Australia: a comparison of approaches

“…The SWWA has experienced a continuous decline in rainfall and increases in temperature since the mid-1970s (Bates et al, 2008). The decreasing health of several tree species and changes within associated fauna and soil communities have been linked with these changing climatic conditions (Cai et al, 2010;Brouwers et al, 2012;Moore et al, 2013) and might represent early indications of a decrease in the resilience of the forest ecosystem (Reyer et al, 2015). The climatic changes in SWWA are projected to continue (CSIRO and BOM, 2007) as well as for Mediterranean climate regions around the world (Klausmeyer and Shaw, 2009;IPCC, 2013).…”

Does woodland condition influence the diversity and abundance of small mammal communities?

“…Relationships indicated that not only E. wandoo condition, but also understorey habitat, were strongly correlated with the small mammal community, highlighting that management should include preservation of E. wandoo trees and the understorey microhabitat necessary for shelter and food resources by small mammals, as seen in other studies (Stephens et al 2012). It should be noted that generalising results over the two locations can be difficult; however, the heterogeneous nature of the E. wandoo decline (and the microhabitat) (Brouwers et al 2013;Moore et al 2013) meant there was habitat variability within a site, as well as a location. Indices of tree canopy condition were retained in the best models describing both mammal abundance and species richness.…”

“…Ten years ago it was noted that trees within two of the three largest patches, the Wandoo Conservation Park and the Dryandra State Forest, were showing signs of decline with symptomatic retraction or loss of canopy (Wandoo Recovery Group 2006;Brouwers et al 2013). Declines of this eucalypt occur heterogeneously, where healthy trees can be adjacent to declining trees (Brouwers et al 2013;Moore et al 2013), differing from other eucalypt decline where large-scale canopy loss occurs (e.g. Eucalyptus marginata, jarrah) (Matusick et al 2012).…”