Ellis L. Yochelson

Ophiuroidea is one of the most suitable marine groups for exploring diversity partitioning in the ocean due to its wide distribution and particular lifestyles. Nevertheless, diversity and its variation have yet to be investigated, and even basic information for large areas such as the eastern tropical Pacific (ETP) is still lacking. The present contribution explores α, β, and γ-diversity patterns of Ophiuroidea from the ETP at four spatial scales (Operational Geographic Units, Ecoregions, Provinces, and Realms). Based on literature records, databases, and scientific collections, an occurrence matrix was constructed for 69 shallow water (0–200 m) Ophiuroidea of the ETP (Mexico–Peru). Diversity evaluation based on rarefaction curves indicated that the observed richness tends to reach the asymptote. At the province and the ecoregion levels, β-diversity was the most important component explaining γ-diversity. The components that mainly contributed to the differentiation between provinces and ecoregions were the intersection of nestedness and β-diversity. PERMANOVA and SIMPER results showed that species composition presented significant differences at all spatial levels. The PCO ordination indicated that the first component (PCO1) explained the variation in species composition in a longitudinal gradient between coastal and oceanic ecoregions, while PCO2 showed a latitudinal gradient. The shade plot yielded three clusters (northern, southern, and widely distributed species). In general, α-diversity was explained by differences in sampling effort and methods; in contrast, β-diversity and its components were mainly explained by patterns and processes occurring at different spatial scales (provinces and ecoregions) such as oceanographic conditions, geographic extension, dispersal, and environmental heterogeneity. This work represents the first attempt to analyze the distribution patterns of shallow-water Ophiuroidea from the ETP.

AbstractEstablished alien land snail species that were introduced into the Western Palaearctic Region from other regions and their spread in the Western Palaearctic are reviewed. Thirteen of the 22 species came from North America, three from Sub-Saharan Africa, two from the Australian region, three probably from the Oriental Region and one from South America. The establishment of outdoor populations of these species was usually first seen at the western or southern rims of the Western Palearctic. Within Europe, the alien species usually spread from south to north and from west to east. The latitudinal ranges of the alien species significantly increased with increasing time since the first record of introduction to the Western Palearctic. The latitudinal mid-points of the Western Palaearctic and native ranges of the species are significantly correlated when one outlier is omitted. There is a general trend of poleward shifts of the ranges of the species in the Western Palaearctic compared to their native ranges. There are three reasons for these shifts: (1) the northward expansion of some species in Western Europe facilitated by the oceanic climate, (2) the impediment to the colonisation of southern latitudes in the Western Palaearctic due to their aridity and (3) the establishment of tropical species in the Mediterranean and the Middle East. Most of the species are small, not carnivorous and unlikely to cause serious ecological or economic damage. In contrast, the recently introduced large veronicellid slugs from Sub-Saharan Africa and the giant African snail Lissachatinafulica could cause economic damage in irrigated agricultural areas or greenhouses in the Mediterranean and the Middle East.

Schistosomiasis is a neglected tropical disease (NTD) found throughout tropical and subtropical Africa. In Madagascar, the condition is widespread and endemic in 74% of all administrative districts in the country. Despite the significant burden of the disease, high-resolution risk maps have yet to b…

Ecosystems face both local hazards, such as over-exploitation, and global hazards, such as climate change. Since the impact of local hazards attenuates with distance from humans, local extinction risk should decrease with remoteness, making faraway areas safe havens for biodiversity. However, isolat…

The Qinghai-Tibetan Plateau (QTP) harbors abundant and diverse plant life owing to its high habitat heterogeneity. However, the distribution pattern of biodiversity hotspots and their conservation status remain unclear. Based on 148,283 high-resolution occurrence coordinates of 13,450 seed plants, w…