Agricultural modification to vegetation drives presence and abundance of a threatened fossorial legless lizard

Abstract

Agricultural modification is one of the main drivers of global biodiversity decline. Vegetation clearance, tillage, grazing, and the application of fertilisers and pesticides have significantly affected native plants and animals. Reptiles can be vulnerable to agricultural practices, and localised declines in reptile biodiversity have been detected. However, the causes of these declines are likely to be many and will vary among reptiles with different life histories. Fossorial reptiles (those that mainly live below ground) are likely to be particularly vulnerable to soil and ground cover disturbance and yet are little studied in the context of agricultural practices. Here, we test the proposition that habitat disturbance caused by agricultural modification is a good predictor of decline or absence of a fossorial lizard. Specifically, we used boosted regression trees to model the relationship between five habitat factors and site abundance of the threatened Pink-tailed Worm-lizard (Aprasia parapulchella; Pygopodidae). We found that vegetation characteristics were the best predictors of A. parapulchella abundance. In particular, the relative contributions to our model of percentage cover of native large tussock-forming grasses and site floristic score were 46% and 33%, respectively. Other variables that contributed to the explanation of abundance were percentage cover of rocks (10%), number of turnable rocks (5%) and relative density of rocks occupied by ants of the size class known to occur with A. parapulchella (5%). Our findings suggest that agricultural management or restoration strategies that promote ground-layer vegetation characteristic of low levels of modification are likely to be most beneficial for the conservation of this species. Our findings and methods may be applicable to understand and study the presence and abundance of other fossorial or semi-fossorial reptiles with specialised habitat preferences. Further research is required to establish the generality of our findings with respect to other such species around the world.

Traits influence reptile responses to fire in a fragmented agricultural landscape

“…An important approach to generate transferable knowledge has been to use traits to identify groups of species that are vulnerable to the effects of habitat disturbance (Keinath et al 2017). For reptiles-a group threatened by habitat loss, fragmentation and modification (Keinath et al 2017;Doherty et al 2020), particularly agriculture (Chapple et al 2021;Wong et al 2021)-a range of traits have proven useful in discriminating responses, including body size, reproduction, diet, habitat position and activity period (Watling and Donnelly 2007;Santos and Cheylan 2013;Carvajal-Cogollo and Urbina-Cardona 2015;Bohm et al 2016;Neilly et al 2018;Val et al 2019;Chergui et al 2020;Williams et al 2021b). While substantial research effort has been directed towards understanding the role of traits in explaining reptile responses to disturbance, consistent trends have not yet emerged.…”

Habitat loss and degradation reduce the abundance of the glossy grass skink, Pseudemoia rawlinsoni

“…Whereas this is partially true for some disturbanceintolerant species (e.g. Sato et al 2014a;Wong et al 2021), the reality is that disturbed sites with exotic vegetation can fulfil the ecological needs of threatened species (Lampert et al 2014;Howland et al 2016), even if suboptimally and in the short term. For example, there are numerous observations of glossy grass skinks occupying sites containing, or dominated by, Kikuyu grass (Cenchrus clandestinus), a globally significant invasive weed (Herrero-Borgon´ on et al 1995).…”