Israel de Faria e Silva

Rapid biodiversity assessment of spiders (Araneae) using semi-quantitative sampling: a case study in a Mediterranean forest

Abstract.  1 A thorough inventory of a Mediterranean oak forest spider fauna carried out during 2 weeks is presented. It used a semi‐quantitative sampling protocol to collect comparable data in a rigorous, rapid and efficient way. Four hundred and eighty samples of one person‐hour of work each were collected, mostly inside a delimited 1‐ha plot. 2 Sampling yielded 10 808 adult spiders representing 204 species. The number of species present at the site was estimated using five different richness estimators (Chao1, Chao2, Jackknife1, Jackknife2 and Michaelis–Menten). The estimates ranged from 232 to 260. The most reliable estimates were provided by the Chao estimators and the least reliable was obtained with the Michaelis–Menten. However, the behavior of the Michaelis–Menten accumulation curves supports the use of this estimator as a stopping or reliability rule. 3 Nineteen per cent of the species were represented by a single specimen (singletons) and 12% by just two specimens (doubletons). The presence of locally rare species in this exhaustive inventory is discussed. 4 The effects of day, time of day, collector experience and sampling method on the number of adults, number of species and taxonomic composition of the samples are assessed. Sampling method is the single most important factor influencing the results and all methods generate unique species. Time of day is also important, in such way that each combination of method and time of day may be considered as a different method in itself. There are insignificant differences between the collectors in terms of species and number of adult spiders collected. Despite the high collecting effort, the species richness and abundance of spiders remained constant throughout the sampling period.

Seasonality of spiders (Araneae) in Mediterranean ecosystems and its implications in the optimum sampling period

Abstract 1. Fields such as ecology, macroecology, and conservation biology rely on accurate and comparable data. This is especially important for mostly unknown and megadiverse taxa such as spiders and regions such as the Mediterranean. Short‐term sampling programmes are increasingly seen as the best option for sampling spiders. Comparability of results, however, demands standard procedures both in methodology and in sampling period. Cost‐efficiency dictates that this period should be the most species rich.

Coleoptera of forensic interest: A study of seasonal community composition and succession in Lisbon, Portugal

Some Coleoptera are recognised as being forensically important as post-mortem interval (PMI) indicators, especially in the later stages of cadaver decomposition. Because insect species and their timings of appearance in cadavers vary according to geographic location, it is important to know their succession patterns, as well as seasonality at a regional level. In this study, we aimed to contribute to broaden this knowledge by surveying beetle communities from the Lisbon area during the four seasons of the year, using piglet carcasses as animal models. Five stages were recognised during the decomposition process and they could be separated taking into account the occurrence and abundance of the specific groups of Coleoptera collected. Decay stages in general recorded higher abundance and richness of beetle species. A total of 82 species were identified, belonging to 28 families, in a total of 1968 adult Coleoptera collected. Autumn yielded the highest values of species abundance and richness, while the lowest values were recorded during winter. Staphylinidae was the most abundant family in all seasons, although in spring and summer Dermestidae was also quite dominant. In general, most species were related to the decay stages, particularly Margarinotus brunneus (Histeridae) and Creophilus maxillosus (Staphylinidae), and also Saprinus detersus (Histeridae) and Thanatophilus sinuatus (Silphidae), while only few were related to the dry stage, namely Oligota pusillima (Staphylinidae) and Dermestidae spp. larvae. On the other hand, Anotylus complanatus and Atheta pertyi (Staphylinidae) were apparently more associated with the fresh and bloated stages, respectively. The presence of some species was markedly seasonal, allowing a season characterisation based on the occurrence of certain taxa, which can be useful for forensic purposes.

Spatial Factors Play a Major Role as Determinants of Endemic Ground Beetle Beta Diversity of Madeira Island Laurisilva

The development in recent years of new beta diversity analytical approaches highlighted valuable information on the different processes structuring ecological communities. A crucial development for the understanding of beta diversity patterns was also its differentiation in two components: species turnover and richness differences. In this study, we evaluate beta diversity patterns of ground beetles from 26 sites in Madeira Island distributed throughout Laurisilva – a relict forest restricted to the Macaronesian archipelagos. We assess how the two components of ground beetle beta diversity (βrepl – species turnover and βrich - species richness differences) relate with differences in climate, geography, landscape composition matrix, woody plant species richness and soil characteristics and the relative importance of the effects of these variables at different spatial scales. We sampled 1025 specimens from 31 species, most of which are endemic to Madeira Island. A spatially explicit analysis was used to evaluate the contribution of pure environmental, pure spatial and environmental spatially structured effects on variation in ground beetle species richness and composition. Variation partitioning showed that 31.9% of species turnover (βrepl) and 40.7% of species richness variation (βrich) could be explained by the environmental and spatial variables. However, different environmental variables controlled the two types of beta diversity: βrepl was influenced by climate, disturbance and soil organic matter content whilst βrich was controlled by altitude and slope. Furthermore, spatial variables, represented through Moran’s eigenvector maps, played a significant role in explaining both βrepl and βrich, suggesting that both dispersal ability and Madeira Island complex orography are crucial for the understanding of beta diversity patterns in this group of beetles.

Spatial distribution of Madeira Island Laurisilva endemic spiders (Arachnida: Araneae).

Abstract Madeira island presents a unique spider diversity with a high number of endemic species, many of which are still poorly known. A recent biodiversity survey on the terrestrial arthropods of the native forest, Laurisilva, provided a large set of standardized samples from various patches throughout the island. Out of the fifty two species recorded, approximately 33.3% are Madeiran endemics, many of which had not been collected since their original description. Two new species to science are reported – Ceratinopsis n. sp. and Theridion n. sp. – and the first records of Poeciloneta variegata (Blackwall, 1841) and Tetragnatha intermedia Kulczynski, 1891 are reported for the first time for Madeira island. Considerations on species richness and abundance from different Laurisilva locations are presented, together with distribution maps for endemic species. These results contribute to a better understanding of spider diversity patterns and endemic species distribution in the native forest of Madeira island.