Biotic integrity of the arthropod communities in the natural forests of Azores

Copyright © Springer Science+Business Media B.V. 2006.The loss of biotic integrity in ecosystems due to human pressure has been receiving much attention from the scientific community. The primary aim of this study is to understand how the increasing human pressure on natural forests in the Azorean archipelago (North Atlantic) is affecting their epigean arthropod communities and which biological parameters it affects most. An expert team did fieldwork covering most of the natural forests (mainly inside nature reserves) of the archipelago using standardized pitfall trapping. To build a multimetric index we tested a number of taxonomic and ecological parameters that can potentially be influenced by disturbance. Sixteen of these were found to be significantly influenced by disturbance in forests. We retained seven metrics due to both, desirable scalability properties and relatively low correlation between them. These included the percentages of endemic and predator species richness and also predator abundance, which are inversely related to disturbance; and the percentages of native and saprophagous species richness and introduced and herbivore abundance, which are positively related to disturbance. All seven metrics were combined in an Index of Biotic Integrity (IBI) value. We then proceeded to understand which potential disturbance factors are influencing the biotic integrity of communities and how such influence is felt. Five disturbance factors were found to influence the IBI, although in different ways: the size and fragmentation of reserves, the distance of sites to the reserve borders, the invasion by alien plants and the density of human paths at the sites. Given that only percentages of taxonomical or ecological characteristics were chosen as metrics, we tested and found the scalability of the IBI to be possible, allowing the comparison of sites with different collecting effort or even the comparison of reserves with different areas and numbers of collecting sites in each. Finally, we propose a novel graphical representation for multimetric indices like the IBI, one which allows retaining much of the information that is usually lost in multimetric indices

Evaluating the performance of species richness estimators: sensitivity to sample grain size

Copyright © 2006 British Ecological Society.1. Fifteen species richness estimators (three asymptotic based on species accumulation curves, 11 nonparametric, and one based in the species-area relationship) were compared by examining their performance in estimating the total species richness of epigean arthropods in the Azorean Laurisilva forests. Data obtained with standardized sampling of 78 transects in natural forest remnants of five islands were aggregated in seven different grains (i.e. ways of defining a single sample): islands, natural areas, transects, pairs of traps, traps, database records and individuals to assess the effect of using different sampling units on species richness estimations. 2. Estimated species richness scores depended both on the estimator considered and on the grain size used to aggregate data. However, several estimators (ACE, Chao1, Jackknife1 and 2 and Bootstrap) were precise in spite of grain variations. Weibull and several recent estimators [proposed by Rosenzweig et al. (Conservation Biology, 2003, 17, 864-874), and Ugland et al. (Journal of Animal Ecology, 2003, 72, 888-897)] performed poorly. 3. Estimations developed using the smaller grain sizes (pair of traps, traps, records and individuals) presented similar scores in a number of estimators (the above-mentioned plus ICE, Chao2, Michaelis-Menten, Negative Exponential and Clench). The estimations from those four sample sizes were also highly correlated. 4. Contrary to other studies, we conclude that most species richness estimators may be useful in biodiversity studies. Owing to their inherent formulas, several nonparametric and asymptotic estimators present insensitivity to differences in the way the samples are aggregated. Thus, they could be used to compare species richness scores obtained from different sampling strategies. Our results also point out that species richness estimations coming from small grain sizes can be directly compared and other estimators could give more precise results in those cases. We propose a decision framework based on our results and on the literature to assess which estimator should be used to compare species richness scores of different sites, depending on the grain size of the original data, and of the kind of data available (species occurrence or abundance data)

Towards systematic conservation planning in the Azores

Several field methodologies, analytical measures and theoretical patterns have been explored for conservation planning for arthropods in native forests of the Azores archipelago. Here, the outcomes are assembled to make recommendations on practical strategies to assess arthropod diversity and to select and manage protected native forests in the Azores. Suggestions are made on how to apply similar plans for conservation of other plant and animal groups in these forests. Potential threats to the Azorean native forest are described and measures to minimize them are proposed. Future studies are also suggested that would improve the present knowledge of arthropod diversity and distribution in Azorean native forests and could assist in the identification of suitable conservation strategies

Arthropods as surrogates of diversity at different spatial scales

Copyright © 2010 Elsevier Ltd. All rights reserved.This study evaluates the effectiveness of taxonomic, colonization and trophic groups of arthropods from native forests of the Azores archipelago as surrogates of the diversity of other arthropod groups and of the remaining arthropods. Consistency in the performance of surrogates was tested across three spatial scales and using two measures of diversity. Pitfall and beating samples from 109 transects, 18 forest fragments and seven islands were analysed. The results showed that Araneae, Hemiptera and small orders taxonomic groups; native, endemic and introduced colonization groups; and the herbivores trophic group were consistent surrogates of the remaining diversity across the three spatial scales analysed, for both alpha and dissimilarity diversities. However, none of the subsets considered was significantly related with all of the other subsets at any of the three spatial scales. The effectiveness of surrogacy was dependent on the spatial level considered, and groups behaved inconsistently depending on the measure of diversity used. The value of a group as a diversity surrogate should be evaluated for a study area for a given spatial scale and diversity measure, in accordance with the scale and measure that will be used for biodiversity assessments and monitoring programs in that area

Diversity and distribution of arthropods in native forests of the Azores archipelago

Since 1999, our knowledge of arthropods in native forests of the Azores has improved greatly. Under the BALA project (Biodiversity of Arthropods of Laurisilva of the Azores), an extensive standardised sampling protocol was employed in most of the native forest cover of the Archipelago. Additionally, in 2003 and 2004, more intensive sampling was carried out in several fragments, resulting in nearly a doubling of the number of samples collected. A total of 6,770 samples from 100 sites distributed amongst 18 fragments of seven islands have been collected, resulting in almost 140,000 specimens having been caught. Overall, 452 arthropod species belonging to Araneae, Opilionida, Pseudoscorpionida, Myriapoda and Insecta (excluding Diptera and Hymenoptera) were recorded. Altogether, Coleoptera, Hemiptera, Araneae and Lepidoptera comprised the major proportion of the total diversity (84%) and total abundance (78%) found. Endemic species comprised almost half of the individuals sampled. Most of the taxonomic, colonization, and trophic groups analysed showed a significantly left unimodal distribution of species occurrences, with almost all islands, fragments or sites having exclusive species. Araneae was the only group to show a strong bimodal distribution. Only a third of the species was common to both the canopy and soil, the remaining being equally exclusive to each stratum. Canopy and soil strata showed a strongly distinct species composition, the composition being more similar within the same stratum regardless of the location, than within samples from both strata at the same location. Possible reasons for these findings are explored. The procedures applied in the sampling protocol are also discussed

Arthropods as surrogates of diversity at different spatial scales

Copyright © 2010 Elsevier Ltd. All rights reserved.This study evaluates the effectiveness of taxonomic, colonization and trophic groups of arthropods from native forests of the Azores archipelago as surrogates of the diversity of other arthropod groups and of the remaining arthropods. Consistency in the performance of surrogates was tested across three spatial scales and using two measures of diversity. Pitfall and beating samples from 109 transects, 18 forest fragments and seven islands were analysed. The results showed that Araneae, Hemiptera and small orders taxonomic groups; native, endemic and introduced colonization groups; and the herbivores trophic group were consistent surrogates of the remaining diversity across the three spatial scales analysed, for both alpha and dissimilarity diversities. However, none of the subsets considered was significantly related with all of the other subsets at any of the three spatial scales. The effectiveness of surrogacy was dependent on the spatial level considered, and groups behaved inconsistently depending on the measure of diversity used. The value of a group as a diversity surrogate should be evaluated for a study area for a given spatial scale and diversity measure, in accordance with the scale and measure that will be used for biodiversity assessments and monitoring programs in that area

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

"[…]. 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)Fundação para a Ciência e a Tecnologia, Portugal

Perceção da qualidade e bem-estar subjetivo na residência de uma Escola Superior de Enfermagem

As Instituições do Ensino Superior estão cada vez mais preocupadas com as questões que dizem respeito à qualidade, pelo que nos últimos anos assistimos a grandes progressos relativamente à qualidade e adequação dos planos de estudos, na formação de docentes e discentes e na modernização dos espaços pedagógicos. No entanto, a área de alojamento em residências universitárias não tem sido alvo de igual forma destas preocupações e investimentos. Assim, este estudo teve por objetivo avaliar a perceção da qualidade que os estudantes alojados numa residência do ensino superior têm dos espaços privados e comuns e simultaneamente conhecer os níveis de bem-estar subjetivo que têm relativamente a algumas vivências do dia-a-dia, os quais se refletem na sua qualidade de vida. Com uma amostra de 108 estudantes alojados na residência da Escola Superior de Enfermagem de Coimbra, iniciou-se o estudo com a realização de reuniões exploratórias com todos os residentes, e com base nestas, construiu-se um questionário que foi aplicado a todos os estudantes alojados no momento. Os resultados obtidos relativamente à perceção da qualidade são discutidos no âmbito de intervenções e investimentos conducentes a maior satisfação com o alojamento e os resultados obtidos relativos ao bem-estar, são discutidos no âmbito da saúde física e mental dos estudantes universitários. Os resultados demonstram que apesar de rapazes e raparigas estarem alojados nas mesmas condições, na maior parte dos casos, as raparigas revelam níveis de satisfação mais baixos do que os rapazes. Relativamente às várias dimensões do Bem-estar, não existem diferenças significativas entre comportamentos e sentimentos de rapazes e raparigas, evidenciando-se níveis de bem-estar pessoal inferiores nas raparigas sobretudo no que se relaciona com a sua individualidade e privacidade

Abundance, spatial variance and occupancy: arthropod species distribution in the Azores

Copyright © 2006 British Ecological Society.1. The positive abundance-occupancy and abundance-variance relationships are two of the most widely documented patterns in population and community ecology. 2. Recently, a general model has been proposed linking the mean abundance, the spatial variance in abundance, and the occupancy of species. A striking feature of this model is that it consists explicitly of the three variables abundance, variance and occupancy, and no extra parameters are involved. However, little is known about how well the model performs. 3. Here, we show that the abundance-variance-occupancy model fits extremely well to data on the abundance, variance and occupancy of a large number of arthropod species in natural forest patches in the Azores, at three spatial extents, and distinguishing between species of different colonization status. Indeed, virtually all variation about the bivariate abundance-occupancy and abundance-variance relationships is effectively explained by the third missing variable (variance in abundance in the case of the abundance-occupancy relationship, and occupancy in the case of the abundance-variance relationship). 4. Introduced species tend to exhibit lower densities, less spatial variance in these densities, and occupy fewer sites than native and endemic species. None the less, they all lie on the same bivariate abundance-occupancy and abundance-variance, and trivariate abundance-variance-occupancy, relationships. 5. Density, spatial variance in density, and occupancy appear to be all the things one needs to know to describe much of the spatial distribution of species

Insect and spider rarity in an oceanic island (Terceira, Azores): true rare and pseudo-rare species

Until now the mechanisms of how recent historical land-use (hereafter called "habitat") changes in island ecosystems shape the distribution of individual insect species have been poorly understood in the field of conservation biology. In the present study we concentrate on the delicate equilibrium of the contribution of habitat island composition (i.e. habitat resource availability) with respect to island insect distribution patterns. In this context we study in detail the distribution patterns of four functional groups (herbivorous sucking insects, herbivorous chewing insects, spiders and other arthropod predators) of endemic, native and exotic arthropod species in a well-studied island of the Azores archipelago (Terceira). Within the bigger context of a standardized sampling program both for epigean and canopy insects and spiders we want to find out which species are truly rare and which are pseudo-rare species in each target habitat. Two dimensions of rarity were measured: abundance and habitat specialization. Two domains of rarity were identified: "among habitats" and "geographic". Some interesting patterns emerged. The high dispersal abilities of many insect and spider species together with the fact that many species from islands tend to be generalists imply that many species tend to be vagrants in several habitats and consequently are locally habitat pseudo-rarities. Two types of local pseudorare species were identified: "habitat (or land-use)" and "host plant" pseudorarities. Some species are rare in one habitat type whilst they are more common in another, often related habitat, or they are relatively rare in many habitats. This is a consequence of a "mass effect", with many species demonstrating a "source-sink" dynamics. Truly regionally rare species are those that are habitat specialists and many of them are threatened endemic species or recently introduced exotic species. We suggest several hypotheses for the patterns found, based on the former larger distribution and disturbance regimes of the native Laurel forest. Insufficient spatial replication in sampling can lead to the conclusion that numerous species appear to be rare because they were sampled in marginal sites or in the edge of their distribution. Since habitat occurrence is a less reliable predictor of the rarity status, more attention should be given to the standardized sampling of many habitats before extracting conclusions about the threatened status of a particular insect or spider species. Our results provide clear evidence that without adequate spatial data on abundance and habitat requirements, rarity status for insects and spiders on islands and elsewhere cannot be appropriately assessed