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Publications

Canopy habitat area effect on the arthropod species densities in the Azores: pondering the contribution of tourist species and other life histories

Publication . Ribeiro, Sérvio P.; Borges, Paulo A. V.

"[…]. We performed a PIAR examining how plant cover area and plant crown structure influence the densities of arthropods in the canopies of one specific island, comparing various distinct natural reserves. Species densities were measured for two functional insect herbivore guilds (sap-sucking and leaf-chewing insects) and the most common predatory assembly in this system (spiders) in three different ways: i) the average number of specimens per plant; ii) the average number of specimens per transect, providing both fine and broad scales of species abundance (see Methods); iii) absolute numbers per reserve. Moreover, we investigated common versus scarce arthropod species distributions between various plant species. […]" (da Introdução)

2010Book part

Open access

Using predictive models of species distribution to validate biodiversity data: case studies for Madeira Island

Publication . Jiménez-Valverde, Alberto; Hortal, Joaquín; Lobo, Jorge M.; Borges, Paulo A. V.; Abreu, Cristina; Aguiar, António F.; Azevedo, Eduardo B.; Boieiro, Mário; Fontinha, Susana; Jardim, Roberto; Oliveira, Paulo; Sérgio, Cecília; Serrano, Artur R. M.; Sim-Sim, Manuela; Nunes, Duarte

Os modelos preditivos de distribuição de espécies são uma importante ferramenta para lidar com a falta de informação biogeográfica existente para a maior parte dos taxa. Com esta técnica, estabelece -se uma relação entre a variável dependente (presença/ausência de uma espécie) e um conjunto de variáveis potencialmente preditoras, e é criado um mapa com a probabilidade de presença da espécie para uma determinada área de interesse. Neste capítulo, é usado o programa Maxent para criar modelos de distribuição potencial de um conjunto seleccionado de espécies, e os resultados obtidos são discutidos com base no conhecimento de especialistas nessas espécies.

2008Book part

Open access

The provisional status of arthropod inventories in the Macaronesian islands

Publication . Lobo, Jorge M.; Borges, Paulo A. V.

"[...]. We examined the available data on the most hyper-diverse group of terrestrial animals (the arthropods) with the aim to assess the general reliability of these Macaronesian inventories. First, we describe the main differences between archipelagos in the year of species description. These calculations allow us to compare the temporal pattern of the taxonomic process in the four archipelagos depending on the origin and range size of the species. Subsequently, we examine the shape and characteristics of discovery curves in order to obtain a provisional picture of the taxonomic completeness of current inventories and the amount of work that still needs to be completed. Lastly, we discuss the implications of our results on our current knowledge of Macaronesian arthropods for each archipelago." (da Introdução)

2010Book part

Open access

Patterns of alpha and beta diversity of epigean arthropods at contrasting land-uses of an oceanic island (Terceira, Azores)

Publication . Cardoso, Pedro; Gaspar, Clara; Dinis, Francisco; Borges, Paulo A. V.

"[…]. To study the effect of land-use change in biological communities it is necessary to understand how are the different components of diversity distributed in space. Diversity has long been separated into different components according to the phenomena that interest ecologists (Whittaker, 1960, 1972): i) local species richness, i.e., alpha (community) diversity that measures the species richness of a local assemblage; ii) beta diversity, the degree of difference between communities (Whittaker et al., 2001), that measures turnover of species between communities and; iii) gamma (regional) diversity, which can be considered an equivalent to alpha diversity on a larger scale, but reflects the allopatric distribution of related taxa. Alpha diversity, of which species richness is just the most visible measure, is perhaps the most studied aspect of diversity. However, probably more important than knowing how many species live in a site at a given time, it is to know what species are these. In islands, where the introduction of non-indigenous species is one of the major threats to indigenous species (Borges et al., 2006; Martín et al., 2008), especially endemics, this question is even more significant. Even if man-made habitats are species rich, they may be empty of species considered as conservation priority and abundant in exotic species (Cardoso et al. 2009a). […]" (da Introdução)

2010Book part

Open access

The Macaronesian province: patterns of species richness and endemism of arthropods

Publication . Triantis, Kostas A.; Borges, Paulo A. V.; Hortal, Joaquín; Whittaker, Robert J.

"[…]. The Macaronesian arthropod fauna displays a number of characteristics typical of oceanic islands, including a high degree of endemism, ranging from 19% for the Azores (Borges et al., 2005a), to 28% for Madeira (Borges et al., 2008a), 30% for Cape Verde (Arechavaleta etal., 2005) and 45% for the Canary Islands (Izquierdo et al., 2004; see Table I). The preponderance of endemic species has made the Macaronesian islands an outstanding area for studies of evolution and speciation, and arthropods from these islands have been the focus of particularly intensive investigation in the last ten years. Numerous biogeographic analyses of Macaronesian arthropod groups have provided valuable insights into the processes regulating species richness as well as the relationships among the region's endemics (e.g. Juan et al.,1996; Arnedo & Ribera, 1999; Borges & Brown, 1999; Emerson et al., 1999, 2006; Emerson & Oromí, 2005; Dimitrov et al., 2008; Borges & Hortal, 2009; Hochkirch & Görzig, 2009). Here we investigate the factors shaping arthropod species richness and patterns of endemism in the Macaronesian archipelagos, considering two levels of analysis: a) individual archipelagos of the Macaronesian region (except Madeira and Salvages due to their limited number of islands), and b) all the islands of the region altogether. We do this following the recently published works of Whittaker et al. (2008) and Borges & Hortal (2009), examining data sets for several taxa from the Macaronesian archipelagos. […]." (da Introdução)

2010Book part

Open access