Linking spatial scale dependence of land-use descriptors and invertebrate cave community composition

Abstract

Citation: Pellegrini TG, Sales LP, Aguiar P, Ferreira RL (2016) Linking spatial scale dependence of land-use descriptors and invertebrate cave community composition. Subterranean Biology 18: 17-38. doi: 10.3897/subtbiol.18.8335 AbstractPatterns of biodiversity respond to habitat disturbances and different land-uses. Those patterns possibly vary according to the spatial scale under analysis. Although other studies have shown such responses for different systems, no study has ever demonstrated spatial-scale influences in subterranean terrestrial communities. Therefore, the objective of this paper was to analyze how land use and cave physical structure could influence the terrestrial cave invertebrate species composition. We also determined the influence of different spatial scale on the structure of invertebrate cave composition. We collected environmental data at local scale (e.g. cave size, substrate and environmental stability). For spatial scale we determined land uses at three different landscape scales; we gathered these data into circular areas of different sizes (50, 100 and 250 meters) with centroids in the cave entrances. We finally performed three Distance Based Linear Modeling analyses to test for differences among the predictability of environmental variables when comparing different spatial scales. The best explanatory variable for cave invertebrate similarities was the percentage of covering of the external environment by limestone outcrops. We confirm the scale-dependence hypothesis through the different patterns showed among distinct buffer areas. Models become more precise when larger scales were analyzed to explain cave invertebrate composition. This suggests that larger scales capture important environmental features that explain the cave fauna similarities more precisely. Additionally, we found a strong influence of limestone outcrops at all landscape scale structuring cave communities.

Energy and speleogenesis: Key determinants of terrestrial species richness in caves

“…In fact, it is not unexpected that the low importance that geographical distance had to account for dissimilarity in species composition (see also Zagmajster et al, 2014 for a case with groundwater crustaceans) ended up disappearing when the caves were split into the two bioregions. Pellegrini et al (2016), working at a much lower spatial extent, also did not find any effect of geographical distance on species dissimilarity.…”

“…Pellegrini et al. (), working at a much lower spatial extent, also did not find any effect of geographical distance on species dissimilarity.…”

“…The altitude of the entrance also seems to be an important factor as it is directly related to temperature and productivity (Culver et al., ; Christman et al., ; Kováč et al., ), and species richness usually positively correlates with the amount of supplied energy (Hüppop, ). The size of the entrance might also correlate with the amount of organic material that goes inside the cave, as well as with the stability of the environment (Pellegrini, Aguiar, Sales, & Ferreira, ). Likewise, the availability of nutrients inside the cave is closely related to the presence of water, which is a factor that influences the physical and chemical features of the subterranean environment (Culver & Pipan, ).…”

Finding answers in the dark: caves as models in ecology fifty years after Poulson and White

“…These include, among others, small emerging drainages (hypotelminorheic habitats), cracks in the karstified rock (epikarst), lava tubes, deep soil and litter strata, air-filled space in taluses and dry riverbeds (Milieu Souterrain Superficiel; MSS) (Culver and Pipan, 2014). In a typical subterranean habitat, such as a cave, it is generally observed that the abundance and diversity of organisms progressively decrease, going from the highly populated and energy-rich twilight zone area to the energy-deprived and poorly populated deeper parts (but see Novak et al 2012 andPellegrini andFerreira 2016 for counterexamples). All the air-and water-filled subterranean spaces representing habitats for subterranean species.…”

The first two hotspots of subterranean biodiversity in South America

“…Protecting the subterranean fauna also requires the protection of the surface riparian areas, including the upstream cave sources (Ford 2005, Reboleira et al 2011, Pellegrini et al 2016). Protection of deep-groundwater species requires protection from both excessive draw further down the system and contamination of the aquifer (Culver and Pipan 2013).…”