Soil compaction and surface-active arthropods in historic, agricultural, alien, and recovering vegetation

Abstract

Soil compaction is a major threat to natural resources. However, little information is available on the impacts of soil compaction on arthropod diversity especially relative to different types of vegetation, land use and restoration activities. In response to this dearth of information, we studied soil compaction, as well as percentage soil moisture and mean leaf litter depth, associated with four vegetation types: natural vegetation (fynbos, the historic condition), agricultural land (vineyards), invasive alien trees, and vegetation cleared of invasive alien trees (recovering vegetation). Our study took place in the Cape Floristic Region, South Africa, a biodiversity hotspot, yet also an area of intense viticulture and heavy invasion by alien plants. We sampled soil surface-active arthropods using pitfall traps, and compared species richness and abundance in different vegetation types with various levels of soil compaction and other soil variables. Overall, vineyards had the highest soil compaction while natural fynbos and aliens had low and comparable compaction. For both arthropod species richness and abundance, the order of the four vegetation types was, from highest to lowest: natural fynbos, alien cleared sites, vineyards, and alien infested sites. Level of soil compaction negatively correlated with arthropod species richness but not with abundance. Neither soil moisture nor leaf litter depth on their own significantly affected arthropod species richness or abundance. While alien trees overall had a strong negative effect on both arthropod species richness and abundance, and much more so than vineyards, the situation is reversible, with removal of aliens being associated with rapid recovery of soil structure and of arthropod assemblages. This is an encouraging sign for restoration.

Rapid recovery of soil arthropod assemblages after exotic plantation tree removal from hydromorphic soils in a grassland‐timber production mosaic

“…This corresponds to results from Moreno‐Mateos et al (), who showed that invertebrate assemblages of restored wetlands converged with reference assemblages between 5 and 10 years. Similar results were found by Magoba et al (), who showed that the removal of alien invasive trees (including Pinus species) can lead to rapid recovery of arthropod assemblages within a few years. This might be an indication that these assemblages are inherently highly responsive to restoration as a result of high resilience (Walker ; Walker et al ).…”

Structure of ground-dwelling arthropod assemblages in vegetation units of Área Natural Protegida Península Valdés, Patagonia, Argentina

“…We performed the db-RDA on the basis of the same data used for the NMDS (Bray-Curtis similarity matrix of square-root of abundances). We selected habitat variables of recognized biological importance for ground-dwelling arthropods (Bestelmeyer and Wiens 2001;Hoffmann and Andersen 2003;Boulton et al 2005;Mazía et al 2006;Li et al 2013;Magoba et al 2015;Ríos-Casanova et al 2015). At the same time, highly collinear variables were removed computing the variance inflation factors (VIF > 10; Legendre and Legendre 2012).…”

An Assessment of Prairie Management Practices for Maintaining Habitat Quality for the Endangered Poweshiek Skipperling Butterfly in Canada

“…Livestock grazing has been widely reported to change soil compaction and soil bulk density levels (see Royer et al, 2008), which can influence soil water content and potentially impact microclimate conditions at the soil surface where larvae of Dakota skipper (Hesperia dacotae (Skinner)) may reside. Magoba et al (2015) found the level of soil compaction is negatively correlated with arthropod species richness near the soil surface, which is where Poweshiek skipperling immature stages reside for almost the entire lifecycle.…”