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

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

Patterns of colonization and species distribution for Azorean arthropods: evolution, diversity, rarity and extinction

Proceedings of the Symposium "Darwin's Mistake and what we are doing to correct it". Ponta Delgada, 19-22 September, 2009.Com base em estudos ecológicos e biogeográficos realizados nos Açores (um arquipélago remoto composto por nove ilhas vulcânicas) durante muitos anos de uma forma continuada, apresentamos um conjunto de questões. O grupo alvo são os artrópodes e o principal habitat é a Laurissilva, a floresta nativa dos Açores. A diversificação das espécies de artrópodes dos Açores é afectada pela idade das ilhas, área das ilhas e seu isolamento. No entanto, os estudos que decorreram durante os últimos dez anos mostram que os vários tipos de grupos taxonómicos e ecológicos são afectados de forma diferente por estes factores, tendo como consequência padrões de distribuição espacial únicos. A distribuição espacial dos artrópodes em cada ilha é causada for "efeitos de massa", muitas espécies possuindo dinâmicas "fonte-sumidouro". As espécies verdadeiramente raras à escala regional são aquelas que são especialistas de um particular habitat, muitas delas sendo espécies endémicas ameaçadas. Embora várias espécies endémicas persistam com populações sumidouro em habitats criados pelo Homem (e.g. florestas exóticas), mais de metade das espécies especialistas da floresta nativa já estão extintas ou poderão extinguir-se no futuro. De facto, aquelas espécies que evoluíram e apenas são encontradas nas florestas nativas foram afectadas de forma dramática como resultado da destruição alargada das florestas nativas dos Açores. Defendemos que a única forma de evitar a extinção de uma fauna única das florestas nativas dos Açores será através de medidas de restauro desta floresta.ABSTRACT: Here we address a list of questions based on long-term ecological and biogeographical studies performed in the Azores, a remote volcanic oceanic archipelago composed by nine islands. The target group are the arthropods, and the main habitat the Laurisilva, the Azorean native forest. Diversification of Azorean arthropod species is affected by island age, area and isolation. However, results obtained for over a decade show that distinct groups are differently affected by these factors, which has lead to the extreme diverse distribution patterns currently observed. Spatial distribution of arthropods in each island may be interpreted as caused by a typical "mass effect", with many species following a "source-sink" dynamics. Truly regionally rare species are those that are habitat specialists, many of them being threatened endemic species. Although various endemics persist as sink populations in human-made habitats (e.g., exotic forests), more than half of the original endemic forest arthropods may already have vanished or may eventually be driven to extinction in the future. Those species which have evolved in and are mainly found in native forests, have been dramatically affected by hitherto unrecognized levels of extinction debt, as a result of extensive destruction of native forest. We argue that immediate action to restore and expand native forest habitat is required to avoid a future of disastrous extinctions of a biologically unique fauna with an unique evolutionary history

Canopy insect herbivores in the Azorean Laurisilva forests: key host plant species in a highly generalist insect community

Copyright © ECOGRAPHY 2005.This article explores patterns of insect herbivore distribution in the canopy of the Laurisilva forests on seven islands in the Azores archipelago. To our knowledge, this is one of the first extensive studied of this type in tree or shrub canopies of oceanic island ecosystems. One of the most frequently debated characteristics of such ecosystems is the likely prevalence of vague, ill-defined niches due to taxonomic disharmony, which may have implications for insect-plant interactions. For instance, an increase in ecological opportunities for generalist species is expected due to the lack of predator groups and reduced selection for chemical defence in host plants. The following two questions were addressed: 1) Are specialists rare species, and insect herbivore species randomly distributed among host plant species in the Azores? 2) Are the variances in insect herbivore species composition, frequency and richness explained by host plants or by regional island effects? We expect a proportional distribution of herbivore species between host plants, influenced by host frequency and distinct island effects; otherwise, deviation from expectation might suggest habitat preference for specific host tree crowns. Canopy beating tray samples were performed on seven islands, comprising 50 transects with 1 to 3 plant species each (10 replicates per species), giving 1320 samples from ten host species trees or shrubs in total. From a total of 129 insect herbivore species, a greater number of herbivore species was found on Juniperus brevifolia (s=65) and Erica azorica (s=53). However, the number of herbivore species per individual tree crown was higher for E. azorica than for any other host, on all islands, despite the fact that it was only the fourth more abundant plant. In addition, higher insect species richness and greater insect abundance were found on the trees of Santa Maria Island, the oldest in the archipelago. Insect species composition was strongly influenced by the presence of E. azorica, which was the only host plant with a characteristic fauna across the archipelago, whereas the fauna of other plant crowns was grouped by islands. The great insect occurrence on E. azorica reflects strong habitat fidelity, but only four species were clearly specialists. Our findings indicate a broadly generalist fauna. The simplicity of Azorean Laurisilva contributed to the understanding of insect-plant mechanisms in canopy forest habitats

Synonymy of Orthomus susanae Serrano & Borges, 2009 with Orthomus annae (Donabauer, 2008) (Coleoptera: Carabidae)

Copyright © 2012 Magnolia Press.[...]. Some time after the publication of their paper in Zootaxa, the authors found out that another Madeiran Orthomus species had been described one month earlier (Donabauer 2008). Taking in consideration the morphological characteristics of the specimens described in both papers and the coincidence of the type localities no doubts remained regarding the synonymy between the two species

Relação entre o número de espécies e o número de táxones de alto nível para a fauna de artrópodes dos Açores

Nesta contribuição pretendemos avaliar a aplicação dos modelos RESTAN, "Relação entre o número de Espécies e o número de Táxones de Alto Nível", à fauna de artrópodes de vários habitats das ilhas dos Açores. Utilizámos várias bases de dados recentemente obtidas baseadas em amostragens estandardizadas de artrópodes epígeos do solo em florestas de áreas protegidas, artrópodes fitófagos e predadores de pastagens semeadas e semi-naturais e artrópodes da copa da árvore endémica Juniperus brevifolia. Os modelos RESTAN são aplicados não só usando dados puramente taxonómicos, mas igualmente agrupando os taxa em termos de estratégias ecológicas (e.g. herbívoros, predadores) e de colonização das ilhas (e.g. endémicos). Deste modo pensamos poder avaliar a aplicabilidade destes modelos em estudos de estrutura de comunidades e de conservação. Para os Açores, a aplicação dos modelos RESTAN constitui uma forma muito prática e eficaz de obter estimativas de diversidade. De facto, em todas as matrizes de dados analisadas a riqueza de espécies pode ser estimada eficazmente usando apenas a riqueza em géneros, sendo a relação linear. Ao nível da família, os modelos estimadores possuem um menor poder explicativo e são melhor explicados por uma função exponencial. O escalonamento de Reservas Florestais Naturais dos Açores em termos de biodiversidade de artrópodes endémicos pode ser efectuado usando informação taxonómica ao nível do género. A aplicação de métodos de estimativa rápida de biodiversidade fica assim facilitada, podendo usar-se parataxonomistas bem treinados para o processo de triagem do grande número de amostras geralmente necessárias em estudos ecológicos. Discute-se igualmente a aplicabilidade dos modelos RESTAN a dados de diversidade alfa, beta e gama.ABSTRACT: In this contribution we examine the predictive power of numbers of higher taxa (orders, families and genera) as surrogates of species richness ("RESTAN" models – models based on linear relationship between species and higher taxa numbers) for the Azorean arthropod fauna. Recently, two large entomological and ecological studies were performed in the Azores, using standardized sampling protocols to estimate the diversity of arthropods in grassland and native forests. We use datasets available from those studies to address a few technical questions: A. what is the impact of using several measures of diversity (alpha, gamma and beta species diversity; Shannon-Wiener index of diversity; Evenness) based on numbers of families and genera for canopy arthropods? For instance, could be predicted that values of beta-diversity decrease with the use of higher-taxa estimates. All the measures of diversity could be used, being the genera the best predictor; B. how well behave the RESTAN models for functional groups of species like grass-feeding and web-building spiders in grasslands? The predictive power of higher-taxa is low using web-building spiders, due to few families being envolved and some genera having many species locally represented; C. assuming at least one sample with no species then there will be also no highertaxa in that sample. Consequently, the curve of the relationship between highertaxa richness and species richness should be anchored to the origin (y= bx). What is the predictive value of this model in comparison with the linear (y =a + bx), log-log (log y = a + b log x) and exponential (y = A • e b x) models? The best fit was obtained with the linear model for the genus-species relationship, but the variables are not normally distributed and the log-log model should be preferable. For the family-species relationship the exponential model is the best. The linear model anchored to the origin (y =bx) has some statistical pitfalls and was of less predictive value; D. in conservation studies what is the predictive value of higher-taxa in ranking protected areas? We found that the numbers of arthropod genera could successfully rank the Natural Forest Reserves as well as numbers of species (using endemic species dataset). We found that in the Azores the predictions of species richness using higher-taxa are quite reasonable, mainly because of low levels of diversity. Therefore, costeffective studies could use only genera, since the species richness of arthropods could be predicted reasonably closely from their genus-level richness. Family and order-level data were less informative for all datasets. We suggest that in the Azores as a consequence of the low levels of species diversification with a great proportion of monospecific genera, the use of parataxonomists trained in genus-level identification could be appropriate for sorting large numbers of ecological samples

Ranking protected areas in the Azores using standardised sampling of soil epigean arthropods

Copyright © Springer 2005.Nineteen areas in seven of the nine Azorean islands were evaluated for species diversity and rarity based on soil epigean arthropods. Fifteen out of the 19 study areas are managed as Natural Forest Reserves and the remaining four were included due to their importance as indigenous forest cover. Four of the 19 areas are not included in the European Conservation network, NATURA 2000. Two sampling replicates were run per study area, and a total of 191 species were collected; 43 of those species (23%) are endemic to the archipelago and 12 have yet to be described. To produce an unbiased multiple-criteria index (importance value for conservation, IV-C) incorporating diversity and rarity based indices, an iterative partial multiple regression analysis was performed. In addition, an irreplaceability index and the complementarity method (using both optimisation and heuristic methods) were used for priority-reserves analyses. It was concluded that at least one well-managed reserve per island is absolutely necessary to have a good fraction of the endemic arthropods preserved. We found that for presence/absence data the suboptimal complementarity algorithm provides solutions as good as the optimal algorithm. For abundance data, optimal solutions indicate that most reserves are needed if we want that at least 50% of endemic arthropod populations are represented in a minimum set of reserves. Consistently, two of the four areas not included in the NATURA 2000 framework were considered of high priority, indicating that vascular plants and bird species used to determine NATURA 2000 sites are not good surrogates of arthropod diversity in the Azores. The most irreplaceable reserves are those located in older islands, which indicates that geological history plays an important role in explaining faunal diversity of arthropods in the Azores. Based both on the uniqueness of species composition and high species richness, conservation efforts should be focused on the unmanaged Pico Alto region in the archipelago’s oldest island, Santa Maria

Worldwide COVID-19 spreading explained: traveling numbers as a primary driver for the pandemic.

The spread of SARS-CoV-2 and the distribution of cases worldwide followed no clear biogeographic, climatic, or cultural trend. Conversely, the internationally busiest cities in all countries tended to be the hardest hit, suggesting a basic, mathematically neutral pattern of the new coronavirus early dissemination. We tested whether the number of flight passengers per time and the number of international frontiers could explain the number of cases of COVID-19 worldwide by a stepwise regression. Analysis were taken by 22 May 2020, a period when one would claim that early patterns of the pandemic establishment were still detectable, despite of community transmission in various places. The number of passengers arriving in a country and the number of international borders explained significantly 49% of the variance in the distribution of the number of cases of COVID-19, and number of passengers explained significantly 14.2% of data variance for cases per million inhabitants. Ecological neutral theory may explain a considerable part of the early distribution of SARS-CoV-2 and should be taken into consideration to define preventive international actions before a next pandemic

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

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

Arthropod distribution in a tropical rainforest: tackling a four dimensional puzzle

Quantifying the spatio-temporal distribution of arthropods in tropical rainforests represents a first step towards scrutinizing the global distribution of biodiversity on Earth. To date moststudies have focused on narrow taxonomic groups or lack a design that allows partitioning of the components of diversity. Here, we consider an exceptionally large dataset (113,952 individuals representing 5,858 species), obtained from the San Lorenzo forest in Panama, where the phylogenetic breadth of arthropod taxa was surveyed using 14 protocols targeting the soil, litter, understory, lower and upper canopy habitats, replicated across seasons in 2003 and 2004. This dataset is used to explore the relative influence of horizontal, vertical and seasonal drivers of arthropod distribution in this forest. We considered arthropod abundance, observed and estimated species richness, additive decomposition of species richness, multiplicative partitioning of species diversity, variation in species composition, species turnover and guild structure as components of diversity. At the scale of our study (2km of distance, 40m in height and 400 days), the effects related to the vertical and seasonal dimensions were most important. Most adult arthropods were collected from the soil/ litter or the upper canopy and species richness was highest in the canopy. We compared the distribution of arthropods and trees within our study system. Effects related to the seasonal dimension were stronger for arthropods than for trees. We conclude that: (1) models of beta diversity developed for tropical trees are unlikely to be applicable to tropical arthropods; (2) it is imperative that estimates of global biodiversity derived from mass collecting of arthropods in tropical rainforests embrace the strong vertical and seasonal partitioning observed here; and (3) given the high species turnover observed between seasons, global climate change may have severe consequences for rainforest arthropods