Global diversity of gastropods (Gastropoda; Mollusca) in freshwater

Abstract

The world's gastropod fauna from continental waters comprises ~ 4,000 valid described species and a minimum of 33-38 independent lineages of Recent Neritimorpha, Caenogastropoda and Heterobranchia (including the Pulmonata). The caenogastropod component dominates in terms of species richness and diversity of morphology, physiology, life and reproductive modes and has produced several highly speciose endemic radiations. Ancient oligotrophic lakes (e.g., Baikal, Ohrid, Tanganyika) are key hotspots of gastropod diversity; also noteworthy are a number of lower river basins (e.g., Congo, Mekong, Mobile Bay). But unlike many other invertebrates, small streams, springs and groundwater systems have produced the most speciose associations of freshwater gastropods. Despite their ecological importance in many aquatic ecosystems, understanding of even their systematics is discouragingly incomplete. The world's freshwater gastropod fauna faces unprecedented threats from habitat loss and degradation and introduced fishes and other pests. Unsustainable use of ground water, landscape modification and stock damage are destroying many streams and springs in rural/ pastoral areas, and pose the most significant threats to the large diversity of narrow range endemics in springs and ground water. Despite comprising only ~5% of the world's gastropod fauna, freshwater gastropods account for ~ 20% of recorded mollusc extinctions. However, the status of the great majority of taxa is unknown, a situation that is exacerbated by a lack of experts and critical baseline data relating to distribution, abundance, basic life history, physiology, morphology and diet. Thus, the already considerable magnitude of extinction and high levels of threat indicated by the lUCN Red List of Threatened Species is certainly a significant underestimate.

Spatial and temporal variation of benthic macroinvertebrates in the Nam Gnom Basin receiving discharged waters from the Nam Theun 2 Reservoir (Lao PDR)

“…Trichoptera, Hemiptera, and freshwater molluscs were among the most diverse groups. This observation is in line with rivers of the Mekong Basin, known to host one of the highest diversity of these groups (Bogan, 2008;De Moor & Ivanov, 2008;Polhemus & Polhemus, 2008;Strong et al, 2008). On the other hand, the low representation of Plecoptera and Crustacean was predictable.…”

Redescripción de Potamolithus supersulcatus Pilsbry, 1896 (Gastropoda, Tateidae) del sur de la cuenca Del Plata

“…A pesar de su importancia al ser referentes de un "hotspost" de biodiversidad (Strong et al, 2008), es muy poco lo que se sabe de las especies de este género. A tal punto que la IUCN (2016) Red List of Threatened Species (www.iucnredlist.org) solo cita siete especies, tres de ellas con datos insuficientes y cuatro con "menor preocupación".…”

“…Sin embargo, estos dos ríos en conjunto están considerados como uno de las dos zonas calientes ("hotspots") de diversidad de gasterópodos de agua dulce presentes en América del Sur (Strong et al, 2008). Este punto caliente de diversidad esta dado principalmente por las especies del género Potamolithus Pilsbry, 1896 (Tateidae).…”

Diversity of Gastropods in the Selected Rivers and Lakes in Bukidnon

“…Compounded by the unpredictable climate change these activities may have adverse impact on species diversity specifically on gastropod fauna of these wetlands. This habitat loss or degradation together with the introduction of exotic species as well as the unsustainable use of water resources are the identified threats to many of the sensitive wetland wildlife [3], [4]. This survey could thus provide part of the baseline data that might be useful for future use.…”