Ranking protected areas in the Azores using standardised sampling of soil epigean arthropods

Abstract

Abstract. Nineteen areas in seven of the nine Azorean islands were evaluated for species diversity and rarity based on soil epigean arthropods. Fifteen out of the 19 study areas are managed as Natural Forest Reserves and the remaining four were included due to their importance as indigenous forest cover. Four of the 19 areas are not included in the European Conservation network, NATURA 2000. Two sampling replicates were run per study area, and a total of 191 species were collected; 43 of those species (23%) are endemic to the archipelago and 12 have yet to be described. To produce an unbiased multiple-criteria index (importance value for conservation, IV-C) incorporating diversity and rarity based indices, an iterative partial multiple regression analysis was performed. In addition, an irreplaceability index and the complementarity method (using both optimisation and heuristic methods) were used for priority-reserves analyses. It was concluded that at least one well-managed reserve per island is absolutely necessary to have a good fraction of the endemic arthropods preserved. We found that for presence/absence data the suboptimal complementarity algorithm provides solutions as good as the optimal algorithm. For abundance data, optimal solutions indicate that most reserves are needed if we want that at least 50% of endemic

Spider biodiversity patterns and their conservation in the Azorean archipelago, with descriptions of new species

“…Data from semi-natural pastures and intensive pastures were collected on three islands (Terceira, Pico and S. Maria) in the years 1994 and 1995 by means of pitfall traps and a 'Vortis' suction sampling machine (see details in Borges, 1999;Borges & Brown, 1999, 2001, 2004. The bulk of our data comes from project BALA (Biodiversity of the Arthropods from the Laurisilva of the Azores), in which from 1999 to 2005 arthropods were collected by means of pitfall traps in the native forests of seven islands (Corvo and Graciosa excluded) (see details in Borges et al, 2005a), but also in natural grassland and some exotic tree plantations (Ecucalyptus spp., Acacia spp., Pittosporum undulatum and Cryptomeria japonica) (Borges et al, unpubl. data).…”

“…Despite this limitation, we still have some recent information from the standardised studies performed in pastureland (Borges, 1999;Borges & Brown, 1999, 2001, 2004, native habitats (Borges et al, 2005a;Borges et al, unpublished data), exotic plantations (Borges et al, unpubl. data) and fruit orchards (Santos et al, 2005).…”

“…Members of this order play an important role in most terrestrial foodwebs, may be very abundant in several habitats and are among the most numerous arthropods from many samples in all kinds of habitats in the Azores (Borges & Brown, 2001, 2004 and elsewhere (Basset, 1991). Moreover, despite the importance of spiders in terrestrial ecosystems, in both species richness and abundance, this arachnid group is rarely considered in evaluating networks of protected areas (but see Skerl, 1999;Cardoso, 2004;Borges et al, 2005a). * Corresponding author.…”

“…This contribution is part of a larger study conducted since 1998 in the Azorean islands (Project BALABiodiversity of the Arthropods of the Laurisilva of the Azores) (see Borges et al, 2000aBorges et al, , 2005a) that aims to survey the Azorean arthropod fauna using standardised sampling protocols at different spatial scales covering most protected areas and native forests in seven of the nine Azorean islands. For this current contribution we use as a starting point the last list of Azorean spiders (Wunderlich, 1992), and include data from recent field studies in pasturelands (Borges, 1999;Borges & Brown, 1999, 2001, 2004, cavernicolous fauna (Borges & Oromí, in press), native forest and grassland habitats (Borges et al, 2000b(Borges et al, , 2005a, and fruit orchards (Santos et al, 2005). The recently published updated list of Azorean fauna and flora (Borges et al, 2005b) also includes a revised list of Azorean spiders (Borges & Wunderlich, 2005) that is reproduced with some updates and additional information (e.g.…”

A spatial scale assessment of habitat effects on arthropod communities of an oceanic island

“…Pittosporum undulatum); semi-natural high-altitude pastures. Protecting pristine forests is considered to be one of the most common and effective conservation strategies worldwide, but it is a particularly challenging task in this archipelago since the original Azorean forests are now restricted to a few high-altitude fragments (see Borges et al, 2005Borges et al, , 2006. The fragments, varying in size from 4 to 1000 ha, are often disturbed by the invasion of introduced species (Silva and Smith, 2004;Borges et al, 2006).…”