Browsing by Author "Aguiar, Carlos A.S."
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- Increasing biodiversity in wood-pastures by protecting small shrubby patchesPublication . Oksuz, Duygu P.; Aguiar, Carlos A.S.; Tápia, Susana; Llop, Esteve; Lopes, Paula; Serrano, Artur; Leal, Ana I.; Branquinho, Cristina; Correia, Otilia; Rainho, Ana; Correia, Ricardo A.; M. Palmeirim, JorgeWood-pastures are grazed systems, widespread across Europe, where natural and economic values often co-exist. Social and economic changes in Europe generate both threats and opportunities to these systems, calling for new or improved management strategies. We studied the potential of increasing the biodiversity of wood-pastures through the promotion of small-scale habitat diversification. More specifically, we evaluated the impact of protecting very small shrubby patches within large Mediterranean wood-pastures. We sampled species assemblages of plants, lichens and coleopterans in 13 small patches (252–3000 m2) with a well developed shrub layer, and 11 plots in the adjacent matrix of virtually shrub free wood-pasture. Despite their very small size, patches had clearly distinct assemblages of all the studied taxa and their presence greatly enhanced the species richness of the studied wood-pasture landscapes. The presence of shrubby patches increased species richness in wood-pastures by 42% for plants, 27% for lichens and 29% for coleopterans (average over two study areas), a very substantial gain considering that patches covered less than 0.5% of the studied wood-pastures. Our results indicate that the protection and promotion of even small shrubby patches is a promising low-cost nature-based strategy to increase the biodiversity value of wood-pasture landscapes, without substantially affecting the economic value of this silvopastoral system, which is an old and important part of the natural and cultural heritage of Europe.
- Questioning the proverb ‘more haste, less speed’: classic versus metabarcoding approaches for the diet study of a remote island endemic geckoPublication . Gil, Vanessa; Pinho, Catarina J.; Aguiar, Carlos A.S.; Jardim, Carolina; Sampaio e rebelo, Rui; Vasconcelos, RaquelDietary studies can reveal valuable information on how species exploit their habitats and are of particular importance for insular endemics conservation as these species present higher risk of extinction. Reptiles are often neglected in island systems, principally the ones inhabiting remote areas, therefore little is known on their ecological networks. The Selvagens gecko Tarentola (boettgeri) bischoffi, endemic to the remote and integral reserve of Selvagens Archipelago, is classified as Vulnerable by the Portuguese Red Data Book. Little is known about this gecko’s ecology and dietary habits, but it is assumed to be exclusively insectivorous. The diet of the continental Tarentola species was already studied using classical methods. Only two studies have used next-generation sequencing (NGS) techniques for this genus thus far, and very few NGS studies have been employed for reptiles in general. Considering the lack of information on its diet and the conservation interest of the Selvagens gecko, we used morphological and DNA metabarcoding approaches to characterize its diet. The traditional method of morphological identification of prey remains in faecal pellets collected over a longer period was compared with metabarcoding of samples collected during rapid surveys. Molecular results revealed that this species is a generalist, feeding on invertebrate, plant and vertebrate items, whereas the morphological approaches were unable to detect the latter two. These results opened up new questions on the ecological role of the Selvagens gecko that deserves to be further explored, such as the possible predation on seabirds, plant services or trophic competition with the sympatric Madeira lizard Teira dugesii. Metabarcoding identified a greater diversity of dietary items at higher taxonomic resolution, but morphological identification enabled calculation of relative abundances and biomasses of ingested arthropods, and detected a dietary shift on invertebrate preys between seasons. Results of this study highlight the global applicability of rapid metabarcoding surveys for understudied taxa on remote islands that are difficult to access. We recommend using the metabarcoding approach, even if ‘speedy’ sampling only is possible, but we must highlight that disregarding long-term ecological data may lead to ‘hasty’ conclusion.
- The contribution of small shrubby patches to the functional diversity of wood-pasturesPublication . Oksuz, Duygu P.; Aguiar, Carlos A.S.; Tápia, Susana; Llop, Esteve; Lopes, Paula; Serrano, Artur; Leal, Ana I.; Correia, Otilia; Matos, Paula; Rainho, Ana; Branquinho, Cristina; Correia, Ricardo A.; M. Palmeirim, JorgeWood-pastures are grazed systems resulting from a long-term use of natural woodlands by humans. These social-ecological systems, covering vast areas of Europe and other temperate regions, have both high biodiversity and economic values, so many are classified as High Nature Value Farmlands. However, in some regions a loss of spatial heterogeneity threatens this natural value. We investigated the potential contribution of tiny shrubby patches to increase spatial heterogeneity and functional diversity in wood-pasture landscapes. Specifically, we compared functional composition (Community Weighted Means) and functional diversity (Functional Dispersion and Functional Evenness) of assemblages of plants, beetles and lichens in those patches (252–3000 m2) and in the wood-pasture matrix. We found that shrubby patches and matrix harbour species assemblages with very distinct functional compositions in all studied taxonomic groups. Evergreen, woody, broad-leafed and fleshy-fruited are better represented in the patches. In beetles, the main differences were a greater prevalence of small-sized and fungivore species in the patches. Shrubby patches also mostly harboured lichens with fruticose- and foliose-broad growth forms, a greater humidity preference, and lower eutrophication tolerance. Moreover, the two indexes used to quantify functional diversity (Functional Dispersion and Functional Evenness) show that, overall, diversity is greater in patches than in the matrix; in patches Functional Dispersion is statistically higher for plants, and Evenness is statistically higher for beetles and lichen. These differences are all consistent with the very distinct ecological conditions in the matrix and patches. The greater overall functional diversity of shrubby patches, and the major differences in functional composition between patches and matrix, observed for all taxa, indicate that these patches greatly enhance the functional diversity of species assemblages in wood-pasture landscapes. Consequently, preserving and promoting tiny shrubby patches is a potentially valuable low-cost management tool to increase biodiversity and improve ecosystem functioning in wood-pasture landscapes.