Conservation of aquatic invertebrates: concerns, challenges and conundrums

Abstract

ABSTRACT1. Invertebrates inhabiting marine and freshwater ecosystems make important contributions to global biodiversity and provide significant services that have cascading effects across ecosystems. However, this group is grossly under-represented in assessments of conservation status and often neglected in targeted aquatic conservation efforts.2. In global assessments of 7857 freshwater invertebrates and 2864 marine invertebrates, 30-34% were considered Data Deficient highlighting the paucity of information for making such assessments. Of the invertebrate groups that could be assessed, those with poor dispersal abilities and high local endemism, such as many gastropods, crayfish and mussels, are the most threatened.3. Springs and subterranean hydrological systems support the highest proportions of threatened freshwater species, while in marine environments coral reefs, lagoons and anchialine systems are particularly vulnerable.4. Key agents of biodiversity decline in aquatic ecosystems are water pollution, overexploitation and harvesting, habitat degradation and destruction, alien invasive species, and climate change. Effects of dams and water management along with pollution from urban, agricultural and forestry sources are the main threats in freshwater ecosystems, whereas a broad range of factors have impacts on marine invertebrates, including biological resource use.5. Significant impediments facing conservation of aquatic invertebrates are limited knowledge of their diversity, the need for broadscale actions to account for connectivity within and across ecosystems, lack of political will and investment, and the prospect that conditions may get worse before they improve, possibly not in time to save some already highly imperilled invertebrate species from extinction.

Causes and consequences of crayfish extinction: Stream connectivity, habitat changes, alien species and ecosystem services

“…Urbanisation poses a significant challenge to freshwater ecosystems (Liyanage & Yamada, 2017), since it is associated with decreased stream flow, altered of connectivity and reduced in functionality of river banks, generally caused by the construction of houses along watercourses (Collier et al, 2016;Janse et al, 2015). Urbanisation poses a significant challenge to freshwater ecosystems (Liyanage & Yamada, 2017), since it is associated with decreased stream flow, altered of connectivity and reduced in functionality of river banks, generally caused by the construction of houses along watercourses (Collier et al, 2016;Janse et al, 2015).…”

“…They cover <1% of the Earth's surface, but support some 10% of the world's species (Collier, Probert, & Jeffrie, 2016). They cover <1% of the Earth's surface, but support some 10% of the world's species (Collier, Probert, & Jeffrie, 2016).…”

“…The assessment of conservation status on 12,621 invertebrate species has shown that freshwater species suffer the highest levels of threat, with significantly more threatened species than either terrestrial or marine invertebrates (Collen et al, 2012). Freshwater invertebrates play a key functional role in food webs (Collier et al, 2016), and many species also supply goods highly valued by humans, including food resources (e.g. several crustaceans and molluscs), medicinal and ornamental products (Elliot & Dobson, 2015).…”

Declining size of adults and juvenile harvest threatens sustainability of a tropical gastropod, Lobatus gigas, fishery

“…Anthropogenic impacts on the world's marine ecosystems and associated biodiversity are widespread, including overfishing (Pauly, Christensen, Dalsgaard, Froese, & Torres, ), pollution (Tewfik, Rasmussen, & McCann, ) and climate change (Brander, ), which can cause interacting negative consequences for wild populations (Collier, Probert, & Jeffries, ), livelihoods and food security (Andrew et al, ). In some cases, overfishing has been shown to change contemporary life history, resulting in reduced adult body size, altered demographics and associated fecundity, most often in size‐selective fisheries (Allendorf & Hard, ; Haarr, Sainte‐Marie, Comeau, Tremblay, & Rochette, ; Landi, Hui, & Dieckmann, ; Valles & Oxenford, ).…”

Colonizing Islands of water on dry land—on the passive dispersal of fish eggs by birds

“…The presence or absence of empirical knowledge on fish egg zoochory is relevant from a conservational point of view. Knowledge on dispersal concepts is essential for predicting the spread of invasive species, for explaining meta‐population dynamics, for explaining patterns of endemism, and for quantifying threats to fish biodiversity in freshwater ecosystems (Bohonak & Jenkins, ; Collier, Probert, & Jeffries, ). We therefore argue that we need a more solid empirical knowledge on fish dispersal into remote water bodies.…”