Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Accueil du site → Doctorat → Espagne → 2013 → Ecología evolutiva, biogeografía y conservación de los coleópteros acuáticos en ecosistemas salinos del mediterráneo

Universidad de Murcia (2013)

Ecología evolutiva, biogeografía y conservación de los coleópteros acuáticos en ecosistemas salinos del mediterráneo

Arribas Blázquez, Paula

Titre : Ecología evolutiva, biogeografía y conservación de los coleópteros acuáticos en ecosistemas salinos del mediterráneo

Evolutionary ecology, biogeography and conservation of water beetles in mediterranean saline ecosystem.

Auteur : Arribas Blázquez, Paula

Université de soutenance : Universidad de Murcia

Grade : Tesis doctorales 2013

Résumé
Due to the singularity of Mediterranean inland saline waters at multiple levels, they constitute an interesting system for further exploration of evolution and ecology of species. This thesis aims to explore some of the main evolutionary and biogeographical processes and patterns of several lineages of water beetles inhabiting these ecosystems. This information aims to contribute to a better understanding of the determinants and mechanisms of species diversification and persistence in these stressful systems and to provide relevant data for the conservation of their biodiversity. Objectives Identify the drivers promoting the contrasting range size between lotic and lentic saline species. Assess the vulnerability of threatened saline species facing climate change. Evaluate and describe cryptic diversity within saline lineages using an integrative approach. Explore the mode and tempo of the evolution of salinity tolerance in water beetle lineage. Identify the determinants of freshwater and saline species distributions at the continental scale. Methodology This thesis combines multiple approaches and methodologies from different disciplines ; specifically, i) DNA sequences were obtained from specimens and analysed using phylogenetic inference to clarify species evolutionary history ; ii) morfometry was applied in wings, body and pronotum of specimens to identify their dispersal capacity and morfological similarity ; iii) thermal physiology was used to evaluate species thermal tolerances and iv) ecological modelling was employed to estimate niche similarity between species, identify main determinants of species distributions and predict their present and future distributions. Conclusions In the diversification of the Enochrus bicolor species group there were two shifts in habitat utilization, which have been accompanied by marked expansions in geographical range size. Selection for dispersal in geologically short-lived lentic systems, rather than broader fundamental niche, could drive the evolution of larger range sizes in lentic taxa compared to those of their lotic relatives. Species may be affected by climatic warming in very different ways, despite having broadly similar ecological and biogeographical traits. The exploration of the different drivers of species vulnerability to climatic warming could be an effective complement to traditional species vulnerability assessments, and could aid the development of more effective conservation strategies in the face of global warming. Within Enochrus falcarius, previously identified as a single species inhabiting saline streams, four divergent entities were identified on the basis of molecular, biogeographical and niche information. Consequently, four species were delimited despite the fact that they showed high morphological similarity. Integrative taxonomy approaches and rapid vulnerability assessments could become a fundamental tool for biodiversity conservation if applied to lineages from threatened habitats with the potential to comprise cryptic diversity. Within the subgenus Lumetus, salinity tolerance appeared multiple times, always associated with periods of global aridification.. The strong correlation of salinity tolerance with the aridity of the habitats in which species are found, and the possibility of multiple and direct transitions from freshwater to saline suggest that tolerance to salinity may be based on a co-opted mechanism developed originally for drought resistance. For some of the main lineages inhabiting European and North African inland waters, lithology can be a major determinant of their broad-scale distributions. Differences in habitat availability mediated by lithology could work synergistically with dispersal limitation to create the contrasting large-scale patterns of lotic and lentic species distribution. The scope for aquatic biota to track a changing climate may be lower than previously proposed, especially for saline lotic species.

Présentation

Version intégrale (23,76 Mb)

Page publiée le 19 novembre 2013, mise à jour le 30 janvier 2019