Reptile responses to anthropogenic habitat modification: A global meta‐analysis

Abstract

Aim:The aim was to determine how reptile populations respond to anthropogenic habitat modification and determine whether species traits and environmental factors influence such responses. Location: Global.Time period: 1981-2018.Major taxa studied: Squamata. Methods:We compiled a database of 56 studies reporting how habitat modification affects reptile abundance and calculated standardized mean differences in abundance (Hedges' g). We used Bayesian meta-analytical models to test whether responses to habitat modification depended on body size, clutch size, reproductive mode, habitat specialization, range size, disturbance type, vegetation type, temperature and precipitation.Results: Based on 815 effect sizes from 376 species, we found an overall negative effect of habitat modification on reptile abundance (mean Hedges' g = −0.43, 95% credible intervals = −0.61 to −0.26). Reptile abundance was, on average, one-third lower in modified compared with unmodified habitats. Small range sizes and small clutch sizes were associated with more negative responses to habitat modification, although the responses were weak and the credible intervals overlapped zero. We detected no effects of body size, habitat specialization, reproductive mode (egglaying or live-bearing), temperature or precipitation. Some families exhibited more negative responses than others, although overall there was no phylogenetic signal in the data. Mining had the most negative impacts on reptile abundance, followed by agriculture, grazing, plantations and patch size reduction, whereas the mean effect of logging was neutral. Main conclusions:Habitat modification is a key cause of reptile population declines, although there is variability in responses both within and between species, families and vegetation types. The effect of disturbance type appeared to be related to the intensity of habitat modification. Ongoing development of environmentally sustainable practices that ameliorate anthropogenic impacts is urgently needed to prevent declines in reptile populations.

Lots of movement, little progress: A review of reptile home range literature

“…Geographically, nearly 50% of studies originated from a single country, the United States of America. We found a stark mismatch between reptile diversity and reptile home range study locations (Roll et al, 2017), reflecting similar gaps seen in reptile abundance studies (Doherty et al, 2020); in particular, the Middle East and Central Africa. Taxonomically, we observed less severe biases, but should still be considered in evaluating the patterns in the available data.…”

Big City Living: A Global Meta-Analysis Reveals Positive Impact of Urbanization on Body Size in Lizards

“…While many individual studies on various urban lizard populations have been investigated, no generalizations can be drawn as to what makes an urban lizard because no quantitative synthesis at the global scale has been conducted. A recent meta-analysis found that human-induced habitat modifications have had negative impacts on reptile populations worldwide (Doherty et al, 2020), yet information regarding traits of successful species will be useful in predicting other species' responses and for the holistic management of urban ecological communities. In order to fill this information gap, here we qualitatively review the state of the literature within this field of urban herpetological research and take a comparative phylogenetic approach to analyze published data on the effects of urbanization on the physiological, morphological, or behavioral traits in lizards worldwide.…”

Climate overrides the effects of land use on the functional composition and diversity of Mediterranean reptile assemblages

“…This knowledge gap is of specific concern in European landscapes, where reptiles and other vertebrates are wedged between land conversion associated with urbanization and agriculture on the one hand, and habitat changes arising from land abandonment, on top of larger‐scale factors (Gibbons et al., 2000; Reading et al., 2010). In spite of a prevalent role of climate, our results support instead an integration of reptiles in regional planning, in order to limit the adverse consequences of both artificialization and land abandonment on their persistence and diversity in climatically suitable areas (Beaudry et al., 2011; Doherty et al., 2020; Socolar et al., 2016). This regional approach is especially necessary as the low dispersal abilities and high ecological specialization of reptiles likely impairs their recolonization following post‐disturbance habitat recovery, unless if assisted by suitable connectivity networks over regional scales.…”

“…In spite of a prevalent role of climate, our results support instead an integration of reptiles in regional planning, in order to limit the adverse consequences of both artificialization and land abandonment on their persistence and diversity in climatically suitable areas (Beaudry et al, 2011;Doherty et al, 2020;Socolar et al, 2016). This regional approach is especially necessary as the low dispersal abilities and high ecological specialization of reptiles likely impairs their recolonization following post-disturbance habitat recovery, unless if assisted by suitable connectivity networks over regional scales.…”

“…In particular, the impacts of anthropogenic land use on the diversity of reptile assemblages remain rarely investigated even at local scales, although species‐level studies reveal the counter effects of increasing pressure on habitats resulting from agriculture and urbanization and of post‐agricultural land abandonment (Atauri & de Lucio, 2001; De Solan et al., 2019; Ribeiro et al., 2009; Todd et al., 2017). Low dispersal, high ecological specialization and top trophic position are often mentioned to explain reptiles’ vulnerability to global changes in general and to these habitat disturbance in particular (Böhm et al., 2013; Fitzgerald et al., 2013; but see Doherty et al., 2020). These species‐level patterns of response do not seem, however, to be systematically related to ecological traits, suggesting complex underlying processes which do not necessarily involve environmental filtering (De Solan et al., 2019; Todd et al., 2017).…”