Community variation of spiders, beetles and isopods in three small island groups of the Aegean Sea: the interplay between history and ecology

Abstract

Aim To study the variation in the species turnover and nestedness components of compositional dissimilarity in a multi‐taxa and multi‐island‐group system. In addition, to examine the influence of several biogeographical drivers on compositional dissimilarity and discuss the findings in the light of the ecological characteristics of taxa and the palaeogeographical histories of island groups. Location A small‐scale system of island groups within the Aegean Sea, namely the Astypalaia, Kalymnos and Nisyros groups, with different palaeogeographical histories. Methods We examined community variation of predatory ground spiders, omnivorous ground beetles and detritivorous terrestrial isopods. Compositional dissimilarity was decomposed for each group, by disentangling all compositional differences (βtotal) into two components, species turnover (βjtu) and nestedness (βjne). Partial Mantel tests were used to test the effects of island area, island elevation and inter‐island distances on βjtu and βjne. Results Compositional dissimilarity levels of all arthropod communities varied among island groups and were primarily dominated by the species turnover component of compositional dissimilarity. Species turnover of spider communities was lower within the old and isolated Astypalaia group compared to the younger and less distant from mainland Kalymnos and Nisyros groups. Elevation differences between islands did not affect compositional dissimilarity. In contrast, area and inter‐island distances significantly affected compositional dissimilarity between islands, albeit only in island groups of continental origin and only in some of the examined arthropod groups. Main conclusions Despite their geographical proximity, the three island groups show differences in compositional dissimilarity patterns which are more pronounced in the predatory arthropod communities. Using multiple taxa and clearly defined palaeogeographical and topographical elements, i.e. island groups, we show that the ecological characteristics of organisms and idiosyncrasies in geography and palaeogeography can be reflected in compositional dissimilarity patterns at small geographical scales.

Effect of distance, area, and climate on the frequency of introduction and extinction events on islands and archipelagos

“…For each island, island area (km 2 ) was calculated in cylindrical equal-area projection. Although the difference in island area is commonly used to explain community similarity or changes in similarity (Carvalho et al 2014, Pitta et al 2017, Longman et al 2018), the same difference in area can be found between two small islands or two large islands, even though the small islands present very few events. We obtained the maximum elevation (m) of most islands from Blackburn et al (2004); for the remaining islands, the elevation values were taken from WorldClim raster data (http:// www.worldclim.org/) at a resolution of 30 arcsecond (approximately 1 km at the equator).…”

“…The elevation data of three remaining islands (Providencia, Penrhyn, and Palmerston) were collected from Internet searches (https://en.wikipedia.org/; http://www.cookislands.org.uk). Although the difference in island area is commonly used to explain community similarity or changes in similarity (Carvalho et al 2014, Pitta et al 2017, Longman et al 2018), the same difference in area can be found between two small islands or two large islands, even though the small islands present very few events. In other words, an island pair with a large area should support more introductions and extinctions compared to a pair with a small area.…”

Contrasting beta diversity of spiders, carabids, and ants at local and regional scales in a black soil region, northeast China

“…Compensation for local species losses in a community, and by stochastic processes mean that loss of species at local level has effect, be it large or small, on regional biodiversity (Hendrickx et al, 2009). Few studies have addressed biodiversity loss in agroecosystems at multiple scales (Pitta et al, 2017).…”

Geography, climate, ecology: What is more important in determining bee diversity in the Aegean Archipelago?

“…Due to their unique characteristics, viz. numerous islands of diverse sizes, complex palaeogeographic history, and variable geomorphology, the Aegean islands have become a model region for studying diversity patterns in well‐studied taxonomic groups of molluscs, arthropods, and plants (Kallimanis et al., ; Kougioumoutzis et al., ; Panitsa, Tzanoudakis, Triantis, & Sfenthourakis, ; Pitta, Kassara, Trichas, Sfenthourakis, & Chatzaki, ; Sfenthourakis & Panitsa, ; Ståhls et al., ; Triantis, Sfenthourakis, & Mylonas, ; Welter‐Schultes & Williams, ), but never for bees (see Petanidou et al., ). Despite their significant role in providing ecosystem services (viz.…”