Vegetation structure as the main source of variability in scorpion assemblages at small spatial scales and further considerations for the conservation of Caatinga landscapes

Abstract

Even at the local scale, environmental changes due of anthropogenic actions represent a source of disturbance in terrestrial ecosystems, forcing species to respond according to their ecological plasticity. Thus, stenotopic species and those with low-dispersal ability will likely be negatively affected by landscape modifications that reduce environmental complexity. In this study, we identify and quantify the effects of biotic and abiotic factors related to habitat complexity on the variation in scorpion assemblages in terms of both species’ richness, abundance and composition across 18 transects covering Caatinga landscapes with different levels of degradation. Using ultraviolet flashlights, we sampled 269 scorpions, belonging to six species and two families. The results showed contrasting patterns of species richness and abundance that depend on the level of habitat complexity. More specifically, we reported that scorpion species richness could be predicted by the number of trees, while the coefficient of variation of the diameter at breast height of trees (cvDBH) is a predictor of scorpion abundance. These findings suggest that vegetation structure is deterministic for the maintenance of scorpion assemblages in Caatinga landscapes. In addition, the cvDBH and tree number may explain 39% and 40% of the variability observed amongst scorpion assemblages in terms of richness difference and species composition, respectively. This study provides insights concerning the development of conservation strategies, clarifying the role of habitat complexity for the preservation of low-dispersal animals in neglected environments, such as those within the Caatinga domain.

Living in a desert: examining scorpion beta diversity in Egyptian drylands from a macroecological perspective

“…Moreover, in the case of Egyptian drylands, these areas are known for their high geological, environmental, and climatic heterogeneity (Boulos 2009;Zahran and Willis 2009). Therefore, such environmental heterogeneity is expected to affect the maintenance of scorpion assemblages, as already observed in a seasonally dry tropical forest in Brazil (Foerster et al 2020;Lira et al 2021a). By analogy, the landscape heterogeneity observed in Egypt may allow the In terms of dβ patterns, the relative importance of their components may be interpreted as an essential proxy for understanding the dispersal capabilities of the studied species (Baselga 2010).…”

“…Again, the scarcity of information about the ecology of scorpions inhabiting desert ecosystems in northern Africa is a strong limiting factor that prevents us from providing a clearer description of how and to what extent the climate affects the distribution of scorpion species in the area. However, a few examples of how vegetation structure plays a vital role in defining community parameters (notably species richness) in scorpion assemblages have been reported elsewhere: species richness is positively related to shrub cover in a North American desert (Polis and McCormick 1987); species abundance and composition covary with vegetation density in some Neotropical semi-arid regions (Foerster et al 2020; Lira et al 2021a).…”

“…We adopted a cell resolution of 0.18° × 0.18° to minimise the number of missing values and enable capturing the potential responses of scorpion assemblages to the selected environmental variables at the local scale. This approach is justified based on previous studies that have demonstrated that species composition among scorpion assemblages may be affected by environmental conditions on a local scale (Foord et al 2015; Foerster et al 2020; Lira et al 2021b).…”

“…As a result of species-specific niche requirements, scorpions' assemblages are influenced by the non-random spatial distribution of suitable microhabitats throughout the landscape (Polis 1990). For example, in a Brazilian semi-arid region, the spatial distribution of these arachnids is often related to vegetation structure (Foerster et al 2020; Lira et al 2021a). According to Mekahlia et al (2021), the distribution and diversity of scorpions in Algeria were influenced by the gradient of aridity, with scorpion abundance being higher in arid and semi-arid climates than in desert climates.…”

Disentangling diversity patterns in Cuban scorpions (Arachnida: Scorpiones)

“…For example, Lira et al (2021a) detected that vegetation cover (biotic variable) is a key factor to scorpion diversity in a Brazilian Atlantic Rainforest. In addition, vegetation structure also plays a role to maintenance of scorpion assemblage on Seasonal Dry Tropical Forest (Foerster et al, 2020;Lira et al, 2021b). At the regional scale, Lira et al (2019a) investigated the effect of the bioclimatic gradient between wet and dry forests on scorpion assemblages in Brazil and found that temperature and precipitation (abiotic variables) were the major explanatory factors of scorpion richness and dβ, which increased toward the dry forest gradient.…”