Posts from the ‘Biogeography’ Category

Nov 4

The dynamics of inselbergs – New paper in Biological Reviews

Since the start of my PhD in 2006, I’ve spent several years of my life walking on inselbergs (i.e. ancient isolated mountains with modest topography) mainly in Africa and Australia, studying the organisms that live there. It was an inspiring and productive endeavor, leading to a lot of published case studies. Yet, some broader insights take time to develop. I believe it’s only when you spend enough time working on a system and after endless discussions with local experts that deeper understanding emerges. In 2017, a meeting was arranged at the University of Rostock, home of Stefan Porembski, arguably the most influential inselberg researcher alive today. As a PhD student I eagerly read and re-read his landmark green book on Inselbergs.

Wouldn’t it be great if we could bundle the insights that emerged in the quarter century after this book? Together with Fernando Silveira and Luiza De Paula, two (at the time) young up and coming inselberg researchers from Brazil we started drawing up some first diagrams and distilled general patterns and processes from the different plant and animal groups we studied and from the different regions we studied: from the Atlantic forest to the Kalahari and back. The paper would not have been possible without the geomorphological and biogeographical insights of Tom Van der Stocken and Falko Buschke who helped to streamline the ideas through various phases and input from a running PhD project by Joren Snoeks. We are proud that this journey now resulted in a synthesis paper published in Biological Reviews. The ecological and evolutionary dynamics of inselbergs. Some pictures of inselbergs featured in the paper are provided below.

https://onlinelibrary.wiley.com/doi/full/10.1111/brv.13150

In the paper, we provide a new liberal definition of inselbergs from a biological perspective, stressing the old age (easily tens of millions of years, often more), unique microhabitats, and isolation as the main defining characteristics. Typical inselbergs are much lower than proper mountains (< 800m) and therefore typically lack strong altitudinal zonation. They also provide a template of habitats that is not limited to the exposed rock. The surrounding vegetation fringe is an integral part of the broader inselberg ecosystem. We also stress the importance of the landscape matrix in which inselbergs are embedded, which can be a source of inselberg species. Inselbergs can house a lot of endemics adapted to the often harsh inselberg conditions. But they can also be ecological refuges and evolutionary refugia for species from the landscape matrix, particularly over long time scales of cyclical environmental change. Finally, we argue that although they resemble islands, only a small subset of the organisms that can be found on inselbergs will experience them as islands. Inselberg specialists with poor dispersal abilities will experience them as islands, while for more mobile species, inselbergs and for generalists, inselbergs may simply provide habitat patches in the broader landscape that can be used. The landscape matrix, therefore, is not simply a barrier to dispersal (as is the case for oceanic islands) but provides a pool of species and habitats that interact with species and habitats on the inselbergs. At the end, we provide a list of major knowledge gaps that may inspire the next decade of inselberg research and can help us to understand the role of these amazing features in our landscapes.

May 8

Figuring out why species are threatened

In a new paper, Falko Buschke tried to test whether vertebrates that differ in conservation status differ in to what extent their ranges can be predicted by spatial and environmental gradients. It turns out there are no strong differences. Instead, models to predict the ranges of the most threatened species perform much worse than models for least concern species. Also, response to broad environmental gradients could not distinguish endangered, threatened or least concern species. This suggests that we may underestimate extinction risk of species if we would try to assess this based on reliance on specific environmental conditions.

The paper is out in Biodiversity & Conservation

Jul 7

Joining the Inselberg Research Initiative

I visited the University of Rostock to consult with some of the world’s leading experts on the ecology of isolated mountain habitats known as inselbergs. We’ll be joining forces for a number of future projects combining insights from plants and animals to better understand how these enigmatic landscape features survived through the ages and how their biota interact with the landscape matrix around them.

https://www.botanik.uni-rostock.de/forschung/inselberg-research-initiative/what-are-inselbergs/

Sep 21

Welcome Mathil!

As from October, Mathil Vandromme will join the research group after having succefully obtained a VLADOC PhD grant awarded by the Flemish Interuniversity Council for Developmental Aid. Mathil will start to work on the potential ecosystem services provided by bromeliad plants that grow in plantations of coffee and cocoa in Nicaragua. After completing her BSc at VUB, she enrolled in the Erasmus Mundus MSc programme in tropical ecology (TROPIMUNDO). During her MSc degree she worked on an elevational gradient in the Monteverde Cloud Forest in Costa Rica.

Feb 2

The scalability of macroecology

Falko wrote a great summary for his recent idea paper in Frontiers of Biogeography!

https://escholarship.org/uc/item/0bp2c1d0

The Solitary Ecologist

No matter at which scale you look at it, nature is remarkable.

Like many others, I was taught ecology in a very hierarchical way: individual organisms are part of a wider populations of species, collections of species form communities and communities come together to make up ecosystems. Similarly, single trees are nested within forests, which aggregate to form biomes. I’m sure you can come up with many comparable examples.

The trouble with such neat spatial hierarchies is that they lure us into believing that if patterns appear similar at several different spatial scales, then the processes leading to these patterns should also be similar. It’s so easy to assume that nature is like a set of Russian Dolls: each daughter exactly the same as its mother, only slightly smaller. But this is not necessarily the case.

View original post 644 more words

Feb 2

Congratulations dr Falko Buschke & dr Tom Pinceel

After just three years, Falko Buschke‘s Erasmus Mundus PhD fellowship came to an end. Just months later he succesfully defended his PhD thesis. Initially drawn to Belgium with the prospect of doing a thesis on community dynamics with a lot of empirical work, Falko soon settled into a different niche. Making use of the IUCN database he set out to explain the distribution patterns of terrestrial vertebrates in Africa. For this he used a very diverse set of statistical tools. He reconstructed biogeographical patterns in Africa based on how species present in different locations respond to spatial and environmental gradients. He experimented with novel ways to define regional species pools and investigated the drivers of patterns of alpha and beta diversity. Finally, he also experimented with spreading dye models and built a neutral metacommunity model to explain different biogeographical patterns in this realm. Overall, it was an exciting journey exploring the interface between community ecology and macro ecology. Falko, it was great having you here. We will miss your wit and humour now you have returned to South Africa… and will continue to follow your adventures on http://solitaryecology.com/

Just two weeks later, Tom Pinceel joined Falko in the league of doctors. After doing a MSc working on genetic patterns in rock pool fairy shrimp, Tom continued along this path and started to explore the hatching strategies of these enigmatic inhabitants of temporary pools worldwide. Tom showed adaptive variation in hatching strategies of pool invertebrates along a gradient of habitat stability. He also revealed that the ancient diversification of fairy shrimp on the Australian continent coincided with a period of intense aridification. When Australia lost most of its rainforests, desert adapted fauna like fairy shrimps seem to have benefited and responded with a spectacular adaptive radiation. This resulted in a nice little booklet with most of his chapters already published. Tom is now continuing his research into delayed hatching as a survival strategy in extreme environments as a prospective post doc. We can only hope he will be able to continue his work in the near future.

Oct 24

NEW PAPER: Exploring the link between ecology and biogeography in African vertebrates

In a new paper out in the journal Ecography, Falko Buschke tried to explain the distribution patterns of all terrestrial vertebrates that occur in sub Sahara Africa using environmental variables and spatial dispersal related variables.

He found that when you map Africa based on how much variation is explained by dispersal based processes vs. environmental niche based filtering, you can see the contours of the biogeographic regions. This suggests that community structuring processes differ among regions within biogeographic realms.

He also showed that corrections for range size are necessary to extract ecologically meaningful patterns from variation partitioning results.

Finally, he found that unexplained variation was highest in species with small distributions… which is worrying from a conservation perspective as these are often threatened. While we can quite accurately predict distributions of widespread animals, we don’t know very well why certain rarer species are range restricted.

http://onlinelibrary.wiley.com/doi/10.1111/ecog.00860/abstract

An African Black Rhino. One of the species in Falko’s database.

Sep 2

Expedition to the Australian outback 2013

Sunset at our campsite at Walga Rock

Where we are going we don’t need roads

During the 2013 expedition we sampled a total of 600 rock pools from 50 inselbergs in Western Australia. The dataset wil be used to get more insight in the drivers of diversity patterns across spatial scales.