Biogeographic history of Western Mediterranean mountain conifers from an ecoinformatic perspective
- Autores: Daniel Romera Romera
- Directores de la Tesis: Diego Nieto Lugilde (dir. tes.), Francisca Alba-Sánchez (dir. tes.)
- Lectura: En la Universidad de Córdoba (ESP) ( España ) en 2026
- Idioma: inglés
- Tribunal Calificador de la Tesis: Naia Morueta Holme (presid.), Salvador Arenas Castro (secret.), Sara Varela González (voc.)
- Programa de doctorado: Programa Oficial de Doctorado en Recursos Naturales y Gestión Sostenible
- Menciones:
- Internacional
- Calificación: Sobresaliente
- Materias:
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- Resumen
One of the major challenges in modern ecology is to gain a deep understanding of how biodiversity at different organization levels responds to different aspects of global change. This is especially relevant in the Western Mediterranean, which, despite its importance in terms of biodiversity and its crucial role as a refugium, is currently being severely affected by climate change. This scenario poses a significant threat to biodiversity in general, and to conifers in particular, with special concern for highly endangered species such as Abies pinsapo Boiss. and Cedrus atlantica (Endl.) Manetti ex Carrière. However, an effective study of these processes requires both comprehensive climate information and robust, powerful tools that enable us to integratively assess how ecological communities will respond to a changing environment.
Although current climatic databases are extremely useful for many applications, they remain limited in terms of spatial and temporal resolution for biogeographical studies, especially at the micro- or mesoscale. Thus, it is necessary to integrate new downscaling approaches into more accessible workflows, enhancing their applicability while also enabling the regional generation of climate products with the spatio-temporal resolution required for biogeographical studies.
Additionally, approaches such as Species Distribution Models (SDMs), which have exploited climate databases for decades, have shown several limitations. To overcome some of these limitations, a new tool has emerged in recent years: Joint Species Distribution Models (JSDMs), which can infer patterns such as species co-occurrence and their phylogenetic and functional relationships. However, unlike SDMs, the resilience of this modelling approach to imperfect detection in the input data has not yet been established.
Moreover, global change is expected to lead to climatic and compositional scenarios that are non-analogous to those observed today. Thus, to fully understand these processes, it is required to investigate how species responded to similar changes, with past periods being our only point of reference for climatic shifts with species extinction rates comparable to those observed today. Although JSDMs have been found to be more robust than traditional SDMs in a paleobiogeographic context, to my knowledge they have yet to be fully leveraged to explore the drivers of species distributions or to produce more realistic paleobiogeographic reconstructions.
In this doctoral thesis, I aim to improve the understanding of the biogeographic history of Abies pinsapo and Cedrus atlantica by leveraging the potential of JSDMs. To do so, I applied climate downscaling methodologies to develop a climate dataset with the spatio-temporal resolution required for biogeographical studies in the Western Mediterranean region. I also tested the functioning and performance of JSDMs when they are built using opportunistic databases. Finally, I compared SDMs and JSDMs under current and past conditions and provided a continuous projection from the Last Glacial Maximum (i.e., 22 ka BP) to 2100 for Western Mediterranean conifer and broadleaved species.
The results of the analyses performed in this thesis provide the first continuous high temporal and spatial resolution climatic dataset for the Western Mediterranean region from 22 ka BP to 2100, offering great potential for use in historical biogeography studies. Furthermore, it was demonstrated that JSDMs tolerate 50–75% data completeness, indicating that opportunistic databases are a valuable resource for JSDMs but require an assessment of data completeness for the target taxa in the study area at the spatial resolution of interest. Finally, the results indicate that JSDMs outperform SDMs under both present and past conditions, improving the projections presented here compared with previous approaches. Specifically, predictions for Cedrus atlantica showed substantial improvement when species cooccurrences were considered through JSDMs, whereas the other target species, Abies pinsapo, may require a finer spatial resolution to capture specific conditions influencing its distribution.
