Food web structure and trophic interactions in Sierra Nevada high-mountain lakes

Food webs and biodiversity in Sierra Nevada lakes

Resumen

The food web in the Sierra Nevada’s fishless lakes is largely influenced conditioned by several environmental factors mainly related to depth and morphometry. Over the past 50 years, numerous studies have explored the trophic compartments of these ecosystems, with a primary focus on the taxonomy and ecology of planktonic species and coleopterans. This manuscript focuses on these key areas of research. In terms of taxonomy, several species have been recorded for the first time globally, such as the phytoplankton Chromulina nevadensis. Other plankton species have been identified for the first time in Spain, including the diatom Achnanthidium macrocephalum and the rotifer Trichocerca relicta, while some, like the North American Daphnia cf. pulex, have been documented for the first time in European high mountain lakes. Ecological research has also focused on biodiversity, life history strategies, stoichiometry and trophic interactions. Key findings include: (i) low species richness and the Shannon-Wiener diversity in planktonic communities, (ii) temperature and mineralization are probably the main factors controlling zooplankton composition,  (iii) evidence supporting the concept of rheostasis in zooplankton, (iv) pioneering insights into the relationship linking organismal stoichiometry and life-history strategies, (v) broad trophic niches in dytiscid beetles primarily feeding on zooplankton, (vi) the discovery of a mutualistic relationship between an epibiont green algae and Daphnia, and (vii) the significant role of multiple interacting environmental factors on the algae-bacteria relationship. Further research directions and broader ecological implications are also discussed.