Research

We love big questions: what determines species diversity? why do populations and communities change in space and time? We use a variety of theory and modeling tools, with link between theory and empirical data always in mind. The wordcloud presents the most common words in some of our key publications. See our main foci below:

Researchgate profile

Google scholar profile

What determines species diversity?

This question, highlighted by Science Magazine as one of the top 25 open questions in science, can be viewed as two, related questions:

1. How can some ecosystems (e.g. tropical forests) harbor hundreds of relatively similar species on small spatial scales?

While many mechanisms have been proposed to enable coexistence (e.g. spatial and temporal variability in the environment, pathogens and herbivores), it is not clear how many species can actually be supported by these mechanisms, under what conditions and whether these conditions are met in reality.

2. Why some ecosystems are species-rich while others are species-poor?

We are especially interested in how and why the level of temporal and spatial variability of the environment, the disturbance regime (e.g. fires, grazing) and latitude shape species diversity.

We are not picky! We study trees, birds, annual plants, bacteria and whatever organisms we get data for.

Spatial variability in populations and communities

Why does species diversity and composition change across space? This is both a fundamental question, and it can shed light on the processes shaping ecosystems. We are interested in all spatial scales:

Large scales - Why does the number of species decline from the equator to the poles?

Intermediate scale - what is the role of dispersal, competition and habitat heterogeneity in determining species turnover?

Small scales - what role do enemies (herbivores, pathogenes) and dispersal play in determining the spatial distributions of trees in forest plots (see pictures)?

Why and how fast does nature change?

"Nothing is constant but change", both at the population level and the level of species diversity and composition. But what governs these changes? And what processes buffer against larger changes?

Generally speaking, both individual populations and communities can be stabilized by local interactions (e.g. competition, the typical explanation) and/or by immigration from outside. But what is their relative roles, in theory and in real ecological communities?

Furthermore, which populations and communities will be more stable and which will change quickly?

Extensive datasets such as the Breeding Bird Survey or BioTIME allow, for the first time, asking general questions about such changes.

Ecological informatics and statistics

How can we say something about the ecological processes that shape communities using observational data?

Theory can help us pick or develop the right data analysis methods - if we apply our methods to alternative theories of community dynamics, we can understand which methods would correctly identify the dynamics, and which methods would lead to erroneous conclusions.

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