Dr. Karl Cottenie
Office: SCIE 2470
Lab: SCIE 2409/2410
My training and research interests lie in the intersection of ecology and multivariate analysis. My formal university education started with a Master's degree on comparing the results of different multivariate methods when analyzing the fish and crustacean community structure of an estuary in Belgium. This thesis already included all the three aspects that will continue to play an important role in my research focus, aquatic environment, community ecology, and biostatistics. Since I wanted a more in-depth knowledge of statistics, I also completed a Master's degree in Statistics. For my PhD research, I studied zooplankton community structure of interconnected ponds. In the different ponds of the "De Maten", two opposing forces potentially shape local zooplankton community structure: different local environmental factors could lead to divergence of the zooplankton communities, while high dispersal rates could homogenize the connected communities (i.e. a metacommunity). My study investigated the relative influence of these local versus regional processes on local zooplankton community structure, diversity and dynamics. I used a complementary approach of both observational (coupled with specific multivariate statistics) and experimental data. I showed that both processes do occur, with local processes of primary importance, but with dispersal necessary to deliver the species adapted to different environmental conditions. My postdoctoral research at the National Center for Ecological Analysis and Synthesis continued with these exiting metacommunity questions, i.e. how dispersal through space (but also through time) influences local community dynamics. For one project I applied the methodologies developed during my PhD study on 158 data sets from different environments, communities, spatial scales, and dispersal modes. I found that local environmental variables with or without an independent dispersal component were the driving forces in structuring local community structure. This also clearly indicated that neutral community dynamics alone, currently a hotly debated subject in ecology, was only important in 9% of the data sets. Other projects looked at how metacommunity dynamics change through time as cladoceran communities establish in new pools; temporal metacommunity dynamics in annual dessert plants (with dispersal through time the perfect time analogue of dispersal through space); spatial, temporal and environment processes at different trophic levels in marine kelp ecosystems in the Channel Islands Marine Reserve of the California coast; comparing different dispersal abilities in freshwater organisms (both lake and stream organisms such as fish, macroinvertebrates, zooplankton, perifyton, ...).
M.Sc. - Biology, Leuven, Belgium, 1996
M.Sc. - Statistics, Leuven, Belgium, 1997
Ph.D. - Ecology, Leuven, Belgium, 2002
My research focuses on metacommunity dynamics , with a special emphasis on aquatic ecosystems . A metacommunity consists of multiple communities in a landscape linked by dispersal of individuals. The metacommunity approach adds a layer of complexity above community dynamics and biodiversity: depending on the degree of dispersal and environmental heterogeneity between different sites, dynamics can be determined by local environmental conditions or by processes in neighbouring sites that are propagated via dispersal of individuals. I employ a quantitative approach to integrate observational, experimental and synthetic data sets, gathered by myself and others, to study this interaction of dispersal and environmental processes. My research will form a continuation of my present and past work. I will focus on three major lines of my research philosophy: the integration of ecology and statistics, the combination of theory, observational and experimental data, and the synthesis of patterns . I will apply these principles to metacommunity dynamics, starting with freshwater communities as model systems for testing theory with observations and experiments. However, since metacommunity dynamics are a new and extremely relevant framework to study natural systems, collaborative projects in other systems (terrestrial, marine) will be valuable in our understanding of natural and manipulated systems. Several broad research questions I want to explore are:
- Three-dimensional metacommunity dynamics: so far, I have mainly studied metacommunity dynamics at single snapshots in time, but adding a temporal dimension to this will be a challenging exercise, both data-analytically and conceptually. This can be done both at two levels, both with observational data and with modeling a specific lake system. The observational data involves time series in interconnected sites. The modeling study should incorporate both the spatially explicit setting, dispersal between the different ponds, local interactions such as competition, predation, input from resting egg bank, etc. The model will receive input from field observations, and will result in determining the relative effect of local versus regional dynamics. These can than be compared to the results from purely observational data, and in a third step will allow to manipulate the model parameters to determine for instance the amounts of dispersal necessary to switch from species sorting to mass effects in this system.
- In the same study system, it would be interesting to compare macroinvertebrate metacommunity dynamics to other components of the ecosystem, phytoplankton, rotifers, fish, zooplankton, bacteria, macrophytes, etc. These groups with different body sizes, dispersal abilities, environment requirements, would form ideal contrasts to the published zooplankon metacommunity results. This is possible method to determine the influence of these factors on metacommunity dynamics.
- I would also continue with the research that I started at NCEAS. Although gathering new data is important to improve the knowledge of particular systems and to test theories and hypotheses, using "old" data to answer new question or to synthesize the current information available in a particular field is indispensable in any science, but especially in ecology. Gathering data is a time-consuming and expensive process, and (re-)using as much as possible only adds to the value of data. Thus I intend to continue to synthesis research results using meta-analysis techniques and collaborative projects.
- However, next to these fundamental ecological questions, I would also like to start applying metacommunity theory to more applied issues. Since metacommunity theory studies the interaction between local environmental and spatial dispersal processes, it will become the new paradigm in conservation biology. Metacommunity theory will be especially useful in the conservation problems regarding reserve design and invasive species/genetically modified organisms. The techniques I developed will be both valuable to design new reserves as to evaluate the ecological effectiveness of certain designs. Also the effectiveness in stopping the spread of invasive species depends on both the knowledge of interactions with the biotic and abiotic environment, as knowledge on dispersal characteristics of the species.
Halpern, B.S., Cottenie, K. & Broitman, B. - Strong top-down control in southern California kelp forest ecosystems. Science (accepted).
Halpern, B.S. & Cottenie, K. - Little evidence for climate effects on local-scale structure and dynamics of California kelp forest communities. Global Change Biology (accepted).
Cottenie, K. - Integrating environmental and spatial processes in ecological community dynamics. Accepted for Ecology Letters 8:1175-1182
Cottenie, K. & De Meester, L. (2005) - Metacommunity structure: synergy of biotic interactions as selective agents and dispersal as fuel. Ecology 85:114-119
Cottenie, K. & De Meester, L. (In Press) - Local interactions and local dispersal in a zooplankton metacommunity. Chapter accepted in the book " Metacommunities : spatial dynamics and ecological communities", editors Marcel Holyoak, Mathew A. Leibold and Robert D. Holt.
Cottenie, K., Nuytten, N., Michels, E. & De Meester, L. (2003) - Zooplankton metacommunity structure: regional versus local biotic and abiotic processes in a set of interconnected ponds. Ecology 84:991-1000
Cottenie, K. & De Meester, L. (2003) - Connectivity and cladoceran species richness in a metacommunity of shallow lakes. Freshwater Biology 48: 823-832
Cottenie, K. & De Meester, L. (2003) - Comment to Oksanen (2001): Reconciling Oksanen (2001) and Hurlbert (1984) . Oikos 100:394-396
Michels, E., Cottenie, K., Neys, L., De Gelas, K., Coppin, P. & De Meester, L. (2001) - Geographical and genetic distances among zooplankton populations in a set of interconnected ponds: a plea for using GIS modelling of the effective geographical distance . Molecular Ecology 10:1929-1938
Maes, J., Taillieu, A., Van Damme, P.A., Cottenie, K. & Ollevier, F. (1998) -Seasonal patterns in the fish and crustaceans community of a turbid temperate estuary (Zeeschelde estuary, Belgium). Estuarine, Coastal and Shelf Science, 47:143-151
BIOL*3120 Community Ecology
ZOO*4350 Biology of Polluted Waters