Refine
Has Fulltext
- yes (2)
Is part of the Bibliography
- yes (2)
Document Type
- Journal article (1)
- Doctoral Thesis (1)
Language
- English (2) (remove)
Keywords
- island biogeography (2) (remove)
How genomic and ecological traits shape island biodiversity - insights from individual-based models
(2020)
Life on oceanic islands provides a playground and comparably easy\-/studied basis
for the understanding of biodiversity in general. Island biota feature many
fascinating patterns: endemic species, species radiations and species with
peculiar trait syndromes. However, classic and current island biogeography
theory does not yet consider all the factors necessary to explain many of these
patterns. In response to this, there is currently a shift in island biogeography
research to systematically consider species traits and thus gain a more
functional perspective. Despite this recent development, a set of species
characteristics remains largely ignored in island biogeography, namely genomic
traits. Evidence suggests that genomic factors could explain many of the
speciation and adaptation patterns found in nature and thus may be highly
informative to explain the fascinating and iconic phenomena known for oceanic
islands, including species radiations and susceptibility to biotic invasions.
Unfortunately, the current lack of comprehensive meaningful data makes studying
these factors challenging. Even with paleontological data and space-for-time
rationales, data is bound to be incomplete due to the very environmental
processes taking place on oceanic islands, such as land slides and volcanism,
and lacks causal information due to the focus on correlative approaches. As
promising alternative, integrative mechanistic models can explicitly consider
essential underlying eco\-/evolutionary mechanisms. In fact, these models have
shown to be applicable to a variety of different systems and study questions.
In this thesis, I therefore examined present mechanistic island models to
identify how they might be used to address some of the current open questions in
island biodiversity research. Since none of the models simultaneously considered
speciation and adaptation at a genomic level, I developed a new genome- and
niche-explicit, individual-based model. I used this model to address three
different phenomena of island biodiversity: environmental variation, insular
species radiations and species invasions.
Using only a single model I could show that small-bodied species with flexible
genomes are successful under environmental variation, that a complex combination
of dispersal abilities, reproductive strategies and genomic traits affect the
occurrence of species radiations and that invasions are primarily driven by the
intensity of introductions and the trait characteristics of invasive
species. This highlights how the consideration of functional traits can promote
the understanding of some of the understudied phenomena in island biodiversity.
The results presented in this thesis exemplify the generality of integrative
models which are built on first principles. Thus, by applying such models to
various complex study questions, they are able to unveil multiple biodiversity
dynamics and patterns. The combination of several models such as the one I
developed to an eco\-/evolutionary model ensemble could further help to identify
fundamental eco\-/evolutionary principles. I conclude the thesis with an outlook
on how to use and extend my developed model to investigate geomorphological
dynamics in archipelagos and to allow dynamic genomes, which would further
increase the model's generality.
Anthropogenic and environmental drivers shape diversity of naturalized plants across the Pacific
(2021)
Aim
The Pacific exhibits an exceptional number of naturalized plant species, but the drivers of this high diversity and the associated compositional patterns remain largely unknown. Here, we aim to (a) improve our understanding of introduction and establishment processes and (b) evaluate whether this information is sufficient to create scientific conservation tools, such as watchlists.
Location
Islands in the Pacific Ocean, excluding larger islands such as New Zealand, Japan, the Philippines and Indonesia.
Methods
We combined information from the most up‐to‐date data sources to quantify naturalized plant species richness and turnover across island groups and investigate the effects of anthropogenic, biogeographic and climate drivers on these patterns. In total, we found 2,672 naturalized plant species across 481 islands and 50 island groups, with a total of 11,074 records.
Results
Most naturalized species were restricted to few island groups, and most island groups have a low number of naturalized species. Island groups with few naturalized species were characterized by a set of widespread naturalized species. Several plant families that contributed many naturalized species globally also did so in the Pacific, particularly Fabaceae and Poaceae. However, many families were significantly over‐ or under‐represented in the Pacific naturalized flora compared to other regions of the world. Naturalized species richness increased primarily with increased human activity and island altitude/area, whereas similarity between island groups in temperature along with richness differences was most important for beta diversity.
Main conclusions
The distribution and richness of naturalized species can be explained by a small set of drivers. The Pacific region contains many naturalized plant species also naturalized in other regions in the world, but our results highlight key differences such as a stronger role of anthropogenic drivers in shaping diversity patterns. Our results establish a basis for predicting and preventing future naturalizations in a threatened biodiversity hotspot.