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

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

Drivers of diversity in Macaronesian spiders and the role of species extinctions

Copyright © 2010 Blackwell Publishing.AIM To identify the biogeographical factors underlying spider species richness in the Macaronesian region and assess the importance of species extinctions in shaping the current diversity. LOCATION The European archipelagos of Macaronesia with an emphasis on the Azores and Canary Islands

Species–area relationships on small islands differ among plant growth forms

Aim: We tested whether species–area relationships of small islands differ among plant growth forms and whether this influences the prevalence of the small-island effect (SIE). The SIE states that species richness on small islands is independent of island area or relates to area in a different way compared with larger islands. We investigated whether island isolation affects the limits of the SIE and which environmental factors drive species richness on small islands. Location: Seven hundred islands (< 100 km2) worldwide belonging to 17 archipelagos. Major taxa studied: Angiosperms. Methods: We applied linear and breakpoint species–area models for angiosperm species richness and for herb, shrub and tree species richness per archipelago separately, to test for the existence of SIEs. For archipelagos featuring the SIE, we calculated the island area at which the breakpoints occurred (breakpoint area) and used linear models to test whether the breakpoint areas varied with isolation. We used linear mixed-effect models to discern the effects of seven environmental variables related to island area, isolation and other environmental factors on the species richness of each growth form for islands smaller than the breakpoint area. Results: For 71% of all archipelagos, we found an SIE for total and herb species richness, and for 59% for shrub species richness and 53% for tree species richness. Shrub and tree species richness showed larger breakpoint areas than total and herb species richness. The breakpoint area was significantly positively affected by the isolation of islands within an archipelago for total and shrub species richness. Species richness on islands within the range of the SIE was differentially affected by environmental factors across growth forms. Main conclusion: The SIE is a widespread phenomenon that is more complex than generally described. Different functional groups have different environmental requirements that shape their biogeographical patterns and affect species–area and, more generally, richness–environment relationships. The complexity of these patterns cannot be revealed when measuring overall plant species richness.Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659Studienstiftung des Deutschen Volkes http://dx.doi.org/10.13039/501100004350Peer Reviewe

The underrepresentation and misrepresentation of invertebrates in the IUCN Red List

Copyright © 2012 Elsevier Ltd. All rights reserved

ISIMEROPE, A NEW GENUS OF HYDROBIIDAE (CAENOGASTROPODA: RISSOOIDEA) FROM GREECE

ABSTRACT Isimerope semele n. gen. and n. sp., a valvatiform hydrobiid from southern continental Greece, is described based on morphological and molecular data. Isimerope is distinguished from other European and circum-Mediterranean valvatiform hydrobiid genera by a unique combination of morphological characters, including distinctive male and female genitalia. Isimerope is differentiated from morphologically similar Graecoarganiella, which is also endemic to Greece, by a 10.15% mean COI sequence divergence. Isimerope semele is composed of three small populations living in disturbed habitats, including springs and a river

Power-law scaling in intratumoral microbiota of colorectal cancer

It has recently been proposed that the study of microbial dynamics in humans may gain insights from island biogeographical theory. Here, we test whether the diversity of the intratumoral microbiota of colorectal cancer tumors (CRC) follows a power law with tumor size akin to the island species-area relationship. We confirm a direct correlation between the quantity of Amplicon Sequence Variants (ASVs) within CRC tumors and tumor sizes, following a (log)power model, explaining 47% of the variation. Understanding the processes involved, potentially through the analogy of tumors and islands, may ultimately contribute to future clinical and therapeutic strategies

Power-law scaling in intratumoral microbiota of colorectal cancer

It has recently been proposed that the study of microbial dynamics in humans may gain insights from island biogeographical theory. Here, we test whether the diversity of the intratumoral microbiota of colorectal cancer tumors (CRC) follows a power law with tumor size akin to the island species-area relationship. We confirm a direct correlation between the quantity of Amplicon Sequence Variants (ASVs) within CRC tumors and tumor sizes, following a (log)power model, explaining 47% of the variation. Understanding the processes involved, potentially through the analogy of tumors and islands, may ultimately contribute to future clinical and therapeutic strategies

Resolving the Azorean knot: a response to Carine & Schaefer (2010)

Copyright © 2012 Blackwell Publishing Ltd.Carine & Schaefer (Journal of Biogeography, 2010, 37, 77–89) suggest that the lack of past climate oscillations in the Azores may have contributed to the low plant endemism in this archipelago compared to that of the Canary Islands, a pattern they term the Azorean diversity enigma. Here we challenge their hypothesis, and discuss how the particular characteristics of the Azores may have driven current diversification patterns in this archipelago. We argue that the restricted number of Azorean endemic species and their wide distribution is explicable by the geological, geographical and ecological attributes of the archipelago. That is, the Azores are too young, too small, and too environmentally homogeneous to have hosted many in situ diversification events, so they do not host as many endemic species as other Macaronesian archipelagos, such as Madeira and especially the Canary Islands

Functional traits of indigenous and exotic ground-dwelling arthropods show contrasting responses to land-use change in an oceanic island, Terceira, Azores

Aim: Land-use change typically goes hand in hand with the introduction of exotic-species, which mingle with indigenous species to form novel assemblages. Here, we compare the functional structure of indigenous and exotic elements of ground-dwelling arthropod assemblages across four land-uses of varying management intensity. Location: Terceira Island (Azores, North Atlantic). Methods: We used pitfall traps to sample arthropods in 36 sites across the four land-uses and collated traits related to dispersal ability, body size and resource use. For both indigenous and exotic species, we examined the impact of land-uses on trait diversity and tested for the existence of non-random assembly processes using null models. We analysed differences in trait composition among land-uses for both indigenous and exotic species with multivariate analyses. We used point-biserial correlations to identity traits significantly correlated with specific land-uses for each element. Results: We recorded 86 indigenous and 116 exotic arthropod species. Under high-intensity land-use, both indigenous and exotic elements showed significant trait clustering. Trait composition strongly shifted across land-uses, with indigenous and exotic species being functionally dissimilar in all land-uses. Large-bodied herbivores dominated exotic elements in low-intensity land-uses, while small-bodied spiders dominated exotic elements in high-intensity land-uses. In contrast, with increasing land-use intensity, indigenous species changed from functionally diverse to being dominated by piercing and cutting herbivores. Main conclusions: Our study revealed two main findings: first, in high-intensity - land-uses, trait clustering characterized both indigenous and exotic elements; second, exotic species differed in their functional profile from indigenous species in all land-use types. Overall, our results provide new insights into the functional role of exotic species in a land-use context, suggesting that, in agricultural landscape, exotic species may contribute positively to the maintenance of some ecosystem functions.Peer reviewe