Dive Into Your Imagination

What is biodiversity?
Biodiversity is the variety of genes, species, communities, and ecosystems on earth. When we talk about biodiversity we typically think about species richness, which is the number of species in a community. 

We have shown that in aquatic rock pools, pools that are more diverse (have more species) are more productive and more stable than pools with fewer species.  Communities with more species are also able to resist invasion more successfully and process resources more efficiently than communities with fewer species.

What decreases biodiversity?
The major causes of reductions in biodiversity are changes in land-use and habitat destruction. More than any other factor - we are causing species to go extinct as we take over their habitats and destroy them to provide goods such as fuel, food, and habitat for ourselves.  Another cause is invasive species.

What is an invasive species?
Invasive species are non-native species that find their way to new regions (such as through ballast water transport). Invasive species are considered second only to habitat loss as major threats to biodiversity. Interestingly, biodiversity has also been shown to protect communities from being invaded by non-native species.

Invasive species are bad for a variety of economic and ecological reasons. From an ecological standpoint invasive species are a concern as they result in homogenization of communities - what this means is that communities become more similar to each other, decreasing biodiversity. Given that biodiversity is important as "insurance" to the continued functioning of ecosystems in a changing world - if communities become more similar to each other there will be a lower chance that species that can adapt to changing environmental conditions will be present in a habitat.

How do invasive species get introduced to an area?
Invasive species are a consequence of many different factors but the dominant one is human transport. Ballast water transport (along shipping lines) is one the main sources for aquatic species invasions. Stocking large fish species is also a major vector of invasive species. On land, movement of humans also plays a large role in species invasions. Rat and goat invasions on islands are two well-known cases where human movement has lead to invasions of non-indigenous species.

What tools do you use to conduct your research?
One important tool we use are microcosms.  Microcosms are small, self-contained, ecological communities. There are lots of natural microcosms: phytotelmata (the communities that form in plant cavities), rock pools, tide pools, rain pools. In our research we study the communities in rock pools, a habitat type that is found all over the world on rocky shores. We use microcosms to explore fundamental ecological questions, such as: how does the number of species in a community affect its stability? or what determines whether an invasive species will successfully invade a community? Its pretty exciting to come up with an idea, test your idea by running an experiment, and get an answer.

What research are you currently working on?
We are currently looking at how climate change affects the structure of food-webs and the stability of communities and are trying to figure out the mechanisms by which invasional meltdowns (increasing rates of invasions over time) are occurring. We are also assembling food-webs for the Arctic and the Antarctic.

What have you been finding about the affects of climate change on food-webs?
We don’t know enough yet to be able to predict how climate change will affect the structure of food webs. One possibility however is that food webs will become driven more by bottom-up processes. Bottom-up means that instead of top predators having the greatest effect, community processes become dominated by lower trophic levels (e.g. plants). 

Biography:
Tamara Romanuk is an Assistant Professor in the Biology Department at Dalhousie University. She teaches Diversity of Plants and Animals, Invertebrate Biology and studies links, nodes, and network structure using both aquatic microcosm communities and simulation modeling.  To get where she is today, Tamara received her Ph.D. in Aquatic Ecology from McMaster University in Canada.  She has held many exciting positions, including her job as a fisheries biologist at the Department of Fisheries and Oceans, as well as an Environmental Researcher, Teacher, and Researcher.  She got her start in the ocean as a SCUBA instructor after graduating with her B.A. from Queen’s University.

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