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Universidad de Córdoba (2018)

Application of spatial analysis techniques to conservation and restoration of Mediterranean Quercus under future climate change scenarios

Duque Lazo, Joaquín

Titre : Application of spatial analysis techniques to conservation and restoration of Mediterranean Quercus under future climate change scenarios

Aplicación de técnicas de análisis espacial para la conservación y restauración del Quercus Mediterráneo bajo escenarios futuros de cambio climático

Auteur : Duque Lazo, Joaquín

Université de soutenance : Universidad de Córdoba

Grade : Doctoral Tesis 2018

Résumé
Global change (Land use change, climatic change, invasive species, land overuse and changes of biogeochemical cycles) together with biotic factors (pathogens and pests) is affecting the health of trees and forests in multiple ways which have triggered forest decline worldwide. Climate change affects forests health through changes mainly in precipitation and temperature. Consequently, severe drought together with biotic factors has been pointed out as the mayor factor involved on the worldwide forest decline. Moreover, climate change might aggravate many of the threats to forests ecosystems, such as drought and pest outbreaks. The process of extensive mortality associated with abiotic and biotic factors, it is known as forest decline, forest dieback or forest decay, and it might affect with variable severity to different species. Forest decline commonly involves multiple, interacting factors often becoming the determination of a single cause unrealistic. Oak ecosystems have been affected by a severe decline and mortality during the last century, mainly caused by abiotic and biotic factors. Oaks decline can be defined as a multicausal syndrome in which biotic and abiotic agents interact over time and space, though producing similar symptoms, ending with the death of the trees. Oak species are worldwide threatened by the oak decline syndrome and it could be considered as one of the mayor ecosystem problems in the south west of the Iberian Peninsula which primary affect to holm (Quercus ilex L.) and cork oak (Quercus suber L.) tree species. Oak decline in the Iberian Peninsula has been mainly related to prolonged drought and the oomycete Phytophthora cinnamomi, though, at lower scale, the xylophage insects are also involved. The oomycete rot oak´s roots constraining the water uptake and drying out the oaks which might be also infected by xylophage insects which feed partly of their life cycle from wood of decaying oak trees. The combination of both agents forms a serious problem to face with. Therefore, assessing the effects of oak decline in the Iberian Peninsula and its triggers factors is a general concern. Moreover, the activity of oak related pest and diseases might be enhanced by the forecasted future climate change. We used the advance of the Geographical Information Systems, data mining and machine learning algorithms together with the analysis of bid data, (large databases, alphanumeric and spatial) to tackle oak decline in Andalusia at landscape level. The databases used in this PhD included The Third Spanish National Forest Inventory (INF3), the Andalusian Network for Damage Monitoring in Forest Ecosystems (RED SEDA) pathogen survey ; the results of the Phytophthora cinnamomi sample testing sample surveys in Southwest Australia, survival data from cork oak afforestation and gridded environmental information at 2000 and 200 m2 spatial resolution. We used Species Distribution Models (SDMs), their ensembles and the beforehand mentioned datasets to assess and analyses the core drivers of forest decline and mortality processes of Quercus ilex and Quercus suber ecosystems in Andalusia, as well as the identification of those limiting factors which promote/reduce/increase/revert/ oak decline. We suggest that the core drivers of forest decline and mortality processes of Quercus ilex and Quercus suber ecosystems in Andalusia might be intensified by climate change. Over this general hypothesis the main objective on this PhD thesis was to assess the spatial distribution of the oak decline in Andalusia. Studying the current spatial distribution of Phytophthora cinnamomi and the xylophage insects, forecast their future spatial distribution in Andalusia ; and assess the main drivers which explain their distribution. Présentation

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