Dr Mads Thomsen

Centre for Marine Ecosystems Research

Adjunct Lecturer

Contact Details

Professional Affiliation

Post-doc: Marine Department, National Environmental Research Institute
University of Aarhus, P.O. Box 4000, Roskilde, Denmark

Qualifications

• Ph.D. Environmental Sciences, University of Virginia, USA (2004).
  Thesis title: Macroalgal distribution patterns and ecological performances in a tidal coastal lagoon, with emphasis on the non-indigenous Codium fragile ssp. tomentosoides.

• M.Sc. Environmental Biology & Geography, Roskilde University, Denmark (1998).
  Thesis title: Studies on the ecology of Sargassum muticum (Yendo) Fensholt in Limfjorden.

General Research Interests

I am an ecologist that study coastal plant and animal communities in Northern Europe, North America and Australasia. My research focuses on how anthropogenic stressors, in particular invasions by non-native species, nutrient pollution, catchment alterations and climate change, impact the structure, productivity and biodiversity of aquatic communities. I combine manipulative experiments, analysis of long-term monitoring data and literature-based meta-analysis to test how patterns in biological communities are generated and maintained.  I am particular interested in ‘facilitation processes’ that increasingly are found to influence community structures, and therefore should be included in coastal management and conservation.  This research provides predictions on how coastal habitats will respond to anthropogenic stressors and recommendations for conservation strategies needed to ameliorate their impacts.

Research Projects

• Marine invasive species. I study a broad range of questions in relation to invasions; How abundant are invaders and how do abundance pattern change with scale? What are the impacts of invaders?  What makes some communities more susceptible to invasions than other? Do invaders have superior traits? Can biogeography and classical succession ecology be linked with invasion biology?

• Gracilaria - a model invader. Gracilaria species are prolific seaweeds in low energy shallow temperate coastal systems worldwide. Several Gracilaria species have been introduced to new regions, probably via oyster transplantations. Gracilaria species are generally stress resistant and often facilitated by native invertebrates. Distribution patterns, recruitment, growth, biological interactions and ecological impacts are compared between introduced and native Gracilaria species on different continents to better understand marine invasions.

• Caulerpa ecology. Several species of Caulerpa seaweeds have received international attention, being considered among the world’s worst biological invaders. Distribution patterns and ecological traits of invasive and non-invasive Caulerpa species are compared from their place of origin to better understand what traits make some species invasive compared to other.

• Ecology and impacts of drift algae. Drift algae often accumulate into large mats in low energy soft-bottom estuaries, particular when and where eutrophication occurs. These accumulations can, in high densities and/or if they decompose, have adverse effects on seagrass meadows, oyster reefs, mussel beds and other benthic animals. I study origin, stability, decomposition thresholds, and impacts on estuarine ecosystems.

• Invertebrate-algal facilitation. Facilitation processes are increasingly included into ecological theory. I study how ubiquitous invertebrates, such as worms, snails and bivalves, create biogenic mini-reefs in soft-bottom systems (= islands of hard substrate which is suitable for inhabitation by sessile species). The appreciation of facilitation processes and productive high diverse biogenic mini-reefs are important for conservation and management of soft-bottom estuaries.

• Biomechanical and hydrodynamic links to biological distribution patterns. Tidal currents and storm generated waves often dislodge seaweeds and invertebrates, or prune them down in size.  I study how hydrodynamic forces and biomechanical properties potentially control distribution and abundance patterns of marine benthic organisms.

• Impacts of anthropogenic stressors on Australasian salt marshes. Impacts of anthropogenic stressors on intertidal salt marshes have long been investigated in North America and Europe. In comparison, less is known about Australasian salt marshes. Manipulative experiments are used to test if anthropogenic stressors, for example nutrient enrichment, affect species distribution and zonation in Australasian salt marshes.

Links to key collaborators

Thomas Wernberg. School of Natural Sciences, Edith Cowan University, Australia. http://www.sons.ecu.edu.au/staff/twernberg.php

Brian R. Silliman. Department of Zoology, University of Florida, USA. http://www.sillimanlab.com/

Karen J. McGlathery. Department of Environmental Sciences, University of Virginia, USA. http://faculty.virginia.edu/mcglathery/

Fernando Tuya: School of Natural Sciences, Edith Cowan University, Australia. http://www.sons.ecu.edu.au/staff/ftuya.php

Peter A. Stæhr. Institute of Biology, Freshwater Biological Laboratory, University of Copenhagen, Denmark. http://www.fbl.ku.dk/pastahr/presentation.html

Alf B. Josefson. Department of Marine Ecology, National Environmental Research Institute, Denmark. http://www2.dmu.dk/1_om_dmu/2_afdelinger/3_hav/person.asp?PersonID=AJ

Marianne Holmer. Institute of Biology, University of Southern Denmark. http://www.mholmer.biology.sdu.dk/