Contrasting biodiversity and food web structure of three temporary freshwater habitats in a tropical biodiversity hotspot

Abstract

In many biomes, a variety of different small freshwater habitats, such as pools and phytotelmata can occur together in the same habitat matrix. However, both the biodiversity and the functioning of these ecosystems remain poorly known. Three freshwater habitat types in a tropical West African biodiversity hotspot were studied. The study demonstrated that animal communities in water‐filled tree holes, temporary ponds and granite rock pools were strongly differentiated with exclusive faunas despite their spatial proximity and similar disturbance in the form of seasonal drought. In particular, granite rock pools stood out with a high gamma diversity. Rock pools were also functionally different from the other two habitat types. The three habitats had contrasting predator assemblages, a differential reliance on primary production and different concentrations of available nutrients. The work illustrates that the biodiversity and functions of small temporary freshwater habitats can be strongly differentiated. This shows the unique and potentially complementary roles that these habitats can fulfil in mediating fluxes of energy and nutrients and preserving aquatic biodiversity in landscapes. Temporary aquatic habitats are typically overlooked in conservation policy and local management plans despite being threatened by habitat transformation. In addition, livestock can threaten savanna ponds, wood exploitation can threaten tree holes, and mining and sediment disruption can threaten rock pools. Hence, better knowledge about the ecological functioning of these ecosystems is vital to the implementation of effective conservation strategies.

Conductivity and water level modulate developmental plasticity and explain distribution patterns in a diverse neotropical Odonata assemblage

“…Rock pools in Australia, Botswana, and South Africa tend to be inhabited by one or two species (Brendonck et al, 2015; Jocqué et al, 2006). Exceptionally five, six, seven, and eight species were found in rock pool clusters from northwestern Australia (Carey, Cross, et al, 2019), south‐western Australia (Pinder et al, 2000), Côte d'Ivoire (Snoeks et al, 2021), and Utah (USA) (Baron et al, 1998). The most likely explanations for the large number of odonates we found include neotropical latitude and humidity.…”

“…Therefore, a granite outcrop can house a highly heterogeneous set of freshwater habitats inhabited by a large diversity of invertebrates with different ecological requirements. Community analyses of tropical rock pools are rare (but see Carey, Cross, et al, 2019;Jocqué et al, 2010;Snoeks et al, 2021).…”

“…Therefore, a granite outcrop can house a highly heterogeneous set of freshwater habitats inhabited by a large diversity of invertebrates with different ecological requirements. Community analyses of tropical rock pools are rare (but see Carey, Cross, et al, 2019; Jocqué et al, 2010; Snoeks et al, 2021). Hydroperiod is likely to be an essential underlying factor since it can restrict the survival of taxa based on the minimum time required to complete the aquatic phase of their life cycle (Brendonck et al, 2015; Schneider & Frost, 1996).…”

Desiccation risk favours prevalence and diversity of tardigrade communities and influences their trophic structure in alpine ephemeral rock pools

“…Tardigrade records in rock pools are extremely limited, having been recorded only seven times in the scientific literature. Interestingly, although only few studies have recorded their existence, their occurrence has been cited in rock pools throughout the world (Namibia, Koste (1996); Ivory Coast, Snoeks et al (2021);South Africa, De Vries (1996); Israel, Spencer et al (1999); Utah, USA, Jocqué et al (2007); Spain, Velasco-González et al (2020); Australia, Boix et al (2016)), emphasizing a potential association between tardigrades and rock pools.…”