Browsing by Author "Santos, Ana M. C."
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- Are island and mainland biotas different? Richness and level of generalism in parasitoids of a microlepidopteran in MacaronesiaPublication . Santos, Ana M. C.; Fontaine, Colin; Quicke, Donald L. J.; Borges, Paulo A. V.; Hortal, JoaquínIsland communities are exposed to several evolutionary and ecological processes that lead to changes in their diversity and structure compared to mainland biotas. These phenomena have been observed for various taxa but not for parasitoids, a key group in terms of community diversity and functioning. Here we use the parasitoid communities associated with the moth Acroclita subsequana (Lepidoptera: Tortricidae) in the Macaronesian region, to test whether species richness differs between islands and mainland, and whether island parasitoid faunas are biased towards generalist species. Host larvae were collected on several islands and adjacent mainland, carefully searched for ectoparasitoid larvae and dissected to recover any endoparasitoids. Parasitoids were classified as idiobionts, which usually have a wide host range (i.e. generalists), or koinobionts that are considered specialists. Mainland species richness was lower than expected by chance, with most of the species being koinobionts. On the other hand, island communities showed a greater proportion of idiobiont species. Overall parasitism rates were similar between islands and mainland, but islands had higher rates of parasitism by idiobionts than expected by chance, and mainland areas showed the highest koinobiont parasitism rates. These results suggest that island parasitoid communities are dominated by generalists, in comparison to mainland communities. Several hypotheses may explain this pattern: (1) generalist parasitoids might have better dispersal abilities; (2) they may be less constrained by ‘sequential dependencies’; and (3) island parasitoids probably have fewer competitors and/or predators, thus favouring the establishment of generalists. New studies including multiple hosts, other habitats, and/or more islands are necessary to identify which of these processes shape island parasitoid communities.
- Arthropod traits as proxies for abundance trends in the Azorean IslandsPublication . Oyarzabal, Guilherme; Cardoso, Pedro; Rigal, François; Boieiro, Mário; Santos, Ana M. C.; Amorim do Rosário, Isabel; Malumbres-Olarte, Jagoba; Costa, Ricardo; Lhoumeau, Sebastian; Pozsgai, Gabor; Gabriel, Rosalina; Borges, Paulo A. V.Human activities drive ecological transformation, impacting island ecosystems from species diversity to ecological traits, mainly through habitat degradation and invasive species. Using two unique long-term datasets we aim to evaluate whether species traits (body size, trophic level, dispersal capacity and habitat occupancy) can predict temporal variations in the abundance of endemic, indigenous (endemic and native non-endemic) and exotic arthropods in the Azores Islands. We found that body size is crucial to predict arthropod abundance trends. Small-bodied herbivorous arthropods showed a decrease in abundance, while large-bodied indigenous arthropods increased in abundance, mainly in well-preserved areas. Also, large-bodied exotic arthropods increased in abundance across the entire archipelago. Moreover, endemic canopy dwellers increased in abundance, while endemic ground-dwellers decreased in abundance. Simultaneously, exotic arthropods showed the opposite result, increasing in abundance in the ground while decreasing in abundance in the canopy. Finally, habitat influenced both endemic and exotic spider abundance trends. Endemic spiders that occupy solely natural habitats experienced a decline in abundance, while exotic spiders in the same habitats increased in abundance. Our study underscores the significance of arthropod species traits in predicting abundance changes in island ecosystems over time, as well as the importance of monitoring species communities. Conservation efforts must extend beyond endangered species to protect non-threatened ones, given the increased extinction risk faced by even common species on islands. Monitoring and restoration programs are essential for preserving island ecosystems and safeguarding endemic arthropod populations.
- Os artrópodes auxiliares generalistas associados aos citrinos na ilha Terceira (Açores)Publication . Borges, Paulo A. V.; Santos, Ana M. C.; Pereira, EnésimaA fauna de artrópodes dos Açores, que foi recentemente listada, é composta por cerca de 2.209 espécies e subespécies (Borges et al., 2005a). Uma fracção importante da fauna de artrópodes dos Açores é constituída por espécies de predadores, incluindo predadores generalistas (e.g. Araneae – aranhas, Hemiptera‑Heteroptera, Neuroptera, Staphylinidae, Diptera‑Syphidae etc.) e parasitoides (Hymenoptera – Parasitica). Os ecossistemas agrícolas são aqueles que mais poderão beneficiar da acção dos predadores generalistas, geralmente designados por auxiliares. No entanto, a densidade dos insectos fitófagos, muitos dos quais constituem pragas, só pode ser controlada pelos auxiliares quando não é muito elevada. Apesar do elevado número de pomares existentes na ilha Terceira (Açores), a superfície ocupada por culturas frutícolas é pequena comparativamente à área coberta por pastagens (as pastagens ocupam 44% da área total; Borges 1999a). No ano 2003, iniciou‑se o projecto INTERFRUTA (projecto de cooperação entre Açores, Madeira e Canárias), que contribuiu para o maior conhecimento dos artrópodes associados a quatro culturas frutícolas (bananeiras, citrinos, macieiras e pessegueiros) da ilha Terceira (ver Santos et al., 2005a, b). Neste trabalho apresenta‑se uma lista comentada e a distribuição das espécies de artrópodes auxiliares encontradas nos pomares de Citrinos. [da Introdução]
- Os artrópodes auxiliares generalistas associados às bananeiras na ilha Terceira (Açores)Publication . Moniz, João; Santos, Ana M. C.; Borges, Paulo A. V.; Pereira, Enésima"A biodiversidade dos artrópodes associados às fruteiras dos Açores era, até há poucos anos, quase completamente desconhecida, resumindo-se apenas a listagens de pragas e indicação de uma ou outra espécie de auxiliar (e.g., Garcia & Furtado, 1980; Schanderl & Almeida, 1992; Cruz De Boelpaepe & Teixeira, 1990; Soares et al., 1992, 1994, 1996; Costa-Comelles et al., 1994). Com o projecto INTERFRUTA (Lopes et al., 2005) foi possível realizar um inventário mais ou menos exaustivo da diversidade de artrópodes predadores generalistas que podem actuar como auxiliares no combate a muitas pragas. Este projecto teve início em 2003 e resultou já num maior conhecimento dos artrópodes associados a quatro culturas frutícolas (bananeiras, citrinos, macieiras e pessegueiros) da Ilha Terceira (ver Santos et al. 2005a, b, 2009). Em 2006 este projecto foi continuado através do INTERFRUTA II. […].Neste trabalho apresenta-se uma listagem das espécies de artrópodes predadores generalistas encontrados em pomares de bananeiras (Musa sp.), com comentários relativos à biologia e distribuição das espécies mais comuns." (da Introdução)
- Os artrópodes auxiliares generalistas associados às Macieiras na ilha Terceira (Açores)Publication . Moniz, João; Santos, Ana M. C.; Pereira, Enésima; Borges, Paulo A. V.Neste trabalho apresenta-se uma listagem das espécies de artrópodes auxiliares encontradas nos pomares de macieiras (Malus sp.) durante o decorrer dos projectos INTERFRUTA e INTERFRUTA II (durante o período de 2003 a 2007), com comentários relativos à biologia e distribuição das espécies mais abundantes.
- Cómo la Macaronesia ha influido en nuestra perspectiva sobre los ecosistemas insularesPublication . Santos, Ana M. C.; Florencio, Margarita; Nogué, Sandra; Patiño, Jairo; Traveset, Anna; Borges, Paulo A. V.Actualmente el estudio de los ecosistemas insulares está pasando por un momento de constantes avances, siendo muchas de las nuevas y relevantes aportaciones fruto de estudios desarrollados en la Macaronesia (Azores, Canarias, Cabo Verde y Madeira). Ésta ha sido la mayor motivación para que el IBIG (Island Biology Interest Group – grupo de interés especial dentro de la AEET y de la SPECO) organizara un simposio dedicado a la Macaronesia, dentro del congreso internacional “Island Biology 2016 – II International Conference on Island Evolution, Ecology and Conservation”, realizado entre los días 18 y 22 de Julio, en Angra do Heroismo (isla Terceira, Azores), Portugal. El objetivo principal del simposio ha sido presentar una visión general de la investigación pasada y presente desarrollada en la región Macaronésica, colocándola en el contexto general de la biogeografía de islas. [...].
- Current climate, but also long‐term climate changes and human impacts, determine the geographic distribution of European mammal diversityPublication . Santos, Ana M. C.; Cianciaruso, Marcus V.; Barbosa, Ana Márcia; Bini, L. Mauricio; Diniz‐Filho, J. Alexandre F.; Faleiro, Frederico V.; Gouveia, Sidney F.; Loyola, Rafael; Medina, Nagore G.; Rangel, Thiago F.; Tessarolo, Geiziane; Hortal, JoaquínAIM: Historical climate variations, current climate and human impacts are known to influence current species richness, but their effects on phylogenetic and trait diversity have been seldom studied. We investigated the relationship of these three factors with the independent variations of species, phylogenetic and trait diversity of European mammals. Considering the position of the 0 ⁰C isotherm in the Last Glacial Maximum as a tipping point, we tested the following hypotheses: northern European assemblages host fewer species than southern European ones; northern areas harbour trait and phylogenetically clustered assemblages, while the more stable southern areas host random or overdispersed assemblages; and species richness correlates positively with human influence, while phylogenetic and trait diversity show clustered patterns in areas with stronger human influence. LOCATION: Western Palaearctic. TIME PERIOD: Current and Late Pleistocene effects on present-day diversity. MAJOR TAXA STUDIED: Terrestrial mammals. METHODS: We used a novel analytical approach based on distance matrices to separate the independent variations of species, phylogenetic and trait diversity, and assessed their relationships with current climate, climate stability and human influence through structural equation models. RESULTS: The species-poor assemblages from northern Europe show higher phylogenetic and trait clustering than the more stable richer southern areas. However, no assemblage presented trait or phylogenetic over dispersion. Current climate is the primary driver of phylogenetic and trait diversity, while species richness is affected similarly by both current and past climates. Higher human influence correlates positively with species richness and trait diversity, both directly and by mediating indirect effects of present climate. MAIN CONCLUSIONS: Current climate, climate stability and human influence affect the studied aspects of diversity, although the form and magnitude of their effects vary through space. Importantly, higher levels of human disturbances correlate with more species rich and trait diverse assemblages, an apparently counterintuitive result that deserves further study.
- Dispersal ability determines the scaling properties of species abundance distributions : a case study using arthropods from the AzoresPublication . Borda-de-Água, Luis; Whittaker, Robert J.; Cardoso, Pedro; Rigal, François; Santos, Ana M. C.; Amorim, Isabel R.; Parmakelis, Aristeidis; Triantis, Kostas A.; Pereira, Henrique M.; Borges, Paulo A. V.Species abundance distributions (SAD) are central to the description of diversity and have played a major role in the development of theories of biodiversity and biogeography. However, most work on species abundance distributions has focused on one single spatial scale. Here we used data on arthropods to test predictions obtained with computer simulations on whether dispersal ability influences the rate of change of SADs as a function of sample size. To characterize the change of the shape of the SADs we use the moments of the distributions: the skewness and the raw moments. In agreement with computer simulations, low dispersal ability species generate a hump for intermediate abundance classes earlier than the distributions of high dispersal ability species. Importantly, when plotted as function of sample size, the raw moments of the SADs of arthropods have a power law pattern similar to that observed for the SAD of tropical tree species, thus we conjecture that this might be a general pattern in ecology. The existence of this pattern allows us to extrapolate the moments and thus reconstruct the SAD for larger sample sizes using a procedure borrowed from the field of image analysis based on scaled discrete Tchebichef moments and polynomials.
- Diversidade da fauna de insectos fitófagos e de inimigos naturais em culturas frutícolas da ilha Terceira, Açores: a importância do maneio e da heterogeneidade ambientalPublication . Santos, Ana M. C.; Borges, Paulo A. V.; Hortal, Joaquín; Rodrigues, Ana C.; Medeiros, Carlos; Azevedo, Eduardo B.; Melo, Catarina; Lopes, David João Horta"A evidência mostra que os artrópodes constituem uma fracção importante da biodiversidade estrutural e funcional dos habitats terrestres (Kim, 1993). Por outro lado, só é possível conservar os processos ecológicos associados aos artrópodes promovendo a gestão correcta dos seus habitats. Para tal, é necessária uma correcta identificação e caracterização das suas comunidades de forma a promover a sua boa gestão. Durante os últimos anos têm sido realizados nos Açores vários estudos de inventariação e caracterização ecológica dos artrópodes em alguns dos habitats mais importantes destas ilhas: i) habitat cavernícola (Borges & Oromí, 1994); ii) pastagens semi-naturais e intensivas (Borges & Brown, 2001, 2003, 2004); iii) florestas nativas dos Açores (Borges et al., 2000, 2005a, b, 2006; Ribeiro et al., 2005). No entanto, na diversidade de usos do solo das ilhas açoreanas, as fruteiras constituem um habitat mal estudado em termos da cadeia trófica de artrópodes (contudo ver Oliveira, 2002). […]" (da Introdução).
- Extinction debt on oceanic islandsPublication . Triantis, Kostas A.; Borges, Paulo A. V.; Ladle, Richard J.; Hortal, Joaquín; Cardoso, Pedro; Gaspar, Clara; Dinis, Francisco; Pereira, Enésima; Silveira, Lúcia M. A.; Gabriel, Rosalina; Melo, Catarina; Santos, Ana M. C.; Amorim, Isabel R.; Ribeiro, Sérvio P.; Serrano, Artur R. M.; Quartau, José A.; Whittaker, Robert J.Habitat destruction is the leading cause of species extinctions. However, there is typically a time-lag between the reduction in habitat area and the eventual disappearance of the remnant populations. These “surviving but ultimately doomed” species represent an extinction debt. Calculating the magnitude of such future extinction events has been hampered by potentially inaccurate assumptions about the slope of species–area relationships, which are habitat- and taxon-specific. We overcome this challenge by applying a method that uses the historical sequence of deforestation in the Azorean Islands, to calculate realistic and ecologically-adjusted species–area relationships. The results reveal dramatic and hitherto unrecognized levels of extinction debt, as a result of the extensive destruction of the native forest:>95%, in<600 yr. Our estimations suggest that more than half of the extant forest arthropod species, which have evolved in and are dependent on the native forest, might eventually be driven to extinction. Data on species abundances from Graciosa Island, where only a very small patch of secondary native vegetation still exists, as well as the number of species that have not been found in the last 45 yr, despite the extensive sampling effort, offer support to the predictions made. We argue that immediate action to restore and expand native forest habitat is required to avert the loss of numerous endemic species in the near future.
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