Spatial and temporal dimensions to the taxonomic diversity of arthropods in an arid grassland savannah

Abstract

Quantifying the drivers of biodiversity variation is a key topic in contemporary ecology. While the geographic distribution of biodiversity is broadly determined by water and energy, local environmental conditions may be important. We valuated the relative effects of spatial and temporal variation on taxonomic diversity of ground living arthropod communities in central South Africa. Seasonal climate variation was a major driver of arthropod abundance, but seasonal effects differed between habitats. We did not find any evidence for modular community structures, even across different habitats, or any evidence for a nested pattern across seasons. Instead, we observed a spatial nestedness which was only partly related to specific habitats. Our results suggest that neutral processes had influenced arthropod community structure, but also that very local processes may have been pivotal in determining local and regional arthropod diversity. Such processes may not necessarily have been neutral, but could have been caused by niche deterministic processes acting at scales smaller the distinct habitat classes we used for our study. We further suggest that alterations in climate likely will have substantial effects on the spatial and temporal distribution of arthropod diversity in this arid region.

The influence of distance to perennial surface water on ant communities in Mopane woodlands, northern Botswana

“…Our results suggest that rainfall increased rather than decreased the effect of distance to water on ant communities. Such an interpretation would agree with previous observations that plant productivity is influenced by processes that occur on very local spatial scales (Martin & Ferrer, 2015), and reiterates recent findings that local conditions may be critical for determining both spatial and temporal variation in arthropod communities (Dalerum et al, 2017). Instead, other factors, for instance related to highly local variation in temperature regimes and moisture levels (Barrow & Parr, 2008), likely influenced the observed seasonal variation in the effects of distance to perennial water.…”

“…A minimum distance of 750 m separated different transects. This sampling design thus enabled us to evaluate variation in ant diversity at multiple spatial scales, which is important for appropriate identification of biodiversity patterns (Dalerum et al, 2017). At each sampling point, we placed three pitfall traps within a 2 m radius.…”

“…Species-rich locations therefore contain unique species, and consequently, species-poor locations do not contribute to the overall taxonomic richness of an area (Ślipiński et al, 2012). The concept of modularity has received a great deal of attention in recent years in the study of trophic networks (reviewed in Miranda, Parrini, & Dalerum, 2013), but the concept is rarely applied in a spatial context (Dalerum, Vries, Pirk, & Cameron, 2017). In a spatial context, modular structures of species distributions would suggest locally distinct species assemblages in which a given species primarily would co-exist only with other species from its specific local assemblage.…”

Altitude effects on spatial components of vascular plant diversity in a subarctic mountain tundra

“…We found a predicted scale dependency of beta diversity, with the patch scale (sample station) having lower beta diversity than the intermediate (transect) or landscape scales, and the intermediate scale having lower beta diversity than the landscape scale. These results contradict observations pointing to a strong importance of local characteristics and processes for shaping biodiversity patterns in plants (Marini, Scotton, Klimek, & Pecile, ) and invertebrates (Dalerum et al, , ), and instead suggest that broad‐scale environmental variation may have been more important for the spatial heterogeneity of plant communities than patch level characteristics. Although local characteristics such as snow cover (When, Lundemo, & Holten, ), soil and topographic properties (Marini, Scotton, Klimek, Isselstein, & Pecile, ), and geological substrate (Trigas, Tsiftsis, Tsiripidis, & Iatrou, ) all influence local plant communities, the magnitude of effects of local conditions may be dictated by constraints set by landscape characteristics.…”

“…invertebrates (Dalerum et al, , 2017, and instead suggest that broad-scale environmental variation may have been more important for the spatial heterogeneity of plant communities than patch level characteristics. Although local characteristics such as snow cover (When, Lundemo, & Holten, 2014), soil and topographic properties (Marini, Scotton, Klimek, Isselstein, & Pecile, 2007), and geological substrate (Trigas, Tsiftsis, Tsiripidis, & Iatrou, 2012) all influence local plant communities, the magnitude of effects of local conditions may be dictated by constraints set by landscape characteristics.…”