Patterns and Disturbance-Induced Drivers of Plant Diversity and Endemism on High Elevation Islands
type: CreativeWork
description: In the seven manuscripts presented in this dissertation I contribute to our understanding of the drivers of plant diversity, endemism and speciation by using empirical, experimental and theoretical approaches. I introduce and define the concept of high elevation islands (HEI), which – in my opinion – are ideal research objects to address ecological and biogeographic questions. I intend to bridge the gap between island biogeography (i.e. by focusing on the global scale) and island ecology (i.e. by addressing the within-island scale). As a model HEI the mountainous island of La Palma (Canary Islands) is used and all field-related research was conducted there. HEIs are found in all major oceans from mid to low latitudes. Characteristic features are elevational range reaching more than 1000m a.s.l. and possessing ecosystems ranging from coastal to alpine systems. The alpine treeline, as the borderline between forest and treeless alpine systems, is therefore fundamental in describing HEIs. Interestingly, I demonstrate that globally treeline elevation on HEIs, which is generally lower on HEIs than on the mainland, is mainly driven by island elevation, and not, as expected, by latitude. Another characteristic feature of HEIs is the phenomenon described by the elevation-driven ecological isolation hypothesis, which suggests increasing speciation rates with elevation due to geographical and environmental isolation. Although island climates are generally considered to be buffered by the surrounding ocean, the reviewed literature indicates that global climate change poses a considerable threat to HEIs, especially to systems adapted to climatic stability (e.g. cloud or laurel forests) and alpine ecosystems. La Palma is a typical trade wind-dominated subtropical HEI hosting a variety of different environmental gradients, subsequent vegetation zones and a rich endemic flora. Topography and climate (including different measures of precipitation variability) express varying importa…
abstract: In the seven manuscripts presented in this dissertation I contribute to our understanding of the drivers of plant diversity, endemism and speciation by using empirical, experimental and theoretical approaches. I introduce and define the concept of high elevation islands (HEI), which – in my opinion – are ideal research objects to address ecological and biogeographic questions. I intend to bridge the gap between island biogeography (i.e. by focusing on the global scale) and island ecology (i.e. by addressing the within-island scale). As a model HEI the mountainous island of La Palma (Canary Islands) is used and all field-related research was conducted there. HEIs are found in all major oceans from mid to low latitudes. Characteristic features are elevational range reaching more than 1000m a.s.l. and possessing ecosystems ranging from coastal to alpine systems. The alpine treeline, as the borderline between forest and treeless alpine systems, is therefore fundamental in describing HEIs. Interestingly, I demonstrate that globally treeline elevation on HEIs, which is generally lower on HEIs than on the mainland, is mainly driven by island elevation, and not, as expected, by latitude. Another characteristic feature of HEIs is the phenomenon described by the elevation-driven ecological isolation hypothesis, which suggests increasing speciation rates with elevation due to geographical and environmental isolation. Although island climates are generally considered to be buffered by the surrounding ocean, the reviewed literature indicates that global climate change poses a considerable threat to HEIs, especially to systems adapted to climatic stability (e.g. cloud or laurel forests) and alpine ecosystems. La Palma is a typical trade wind-dominated subtropical HEI hosting a variety of different environmental gradients, subsequent vegetation zones and a rich endemic flora. Topography and climate (including different measures of precipitation variability) express varying importa…
author: Irl, Severin D. H.
date published: 2014-12-16
date modified: 2026-07-27T18:49:40Z
provider: Universität Bayreuth
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Universität Bayreuth