This photo shows a live Louisiana crayfish (Procambarus clarkii). The species is native to the southern US but established in many regions of the world, including the North American Great Lakes. It has caused declines in native animals and plants and the transport of disease. Despite the demonstrated risks from moving this species, it is still actively transported around the world for the aquarium, live food, live bait and biological supplies trades. This shipment cost just a few dollars for half a dozen individuals, and was sent to me at the University of Notre Dame, far outside its native range.
This is one example of the problems of invasive species. As a globalized society we move billions of individual plants and animals around the globe annually. Most of these species improve our welfare, for example as crops and pets, but some escape captivity and become prolific. These are referred to as invasive species, and are one of the strongest drivers of global biodiversity loss.
My research explores the links and feedbacks among global environmental change, human economic systems and human behavior. As society becomes more globalized, and as human populations grow, we become increasingly reliant on patterns of production and trade that have serious environmental, economic and human health consequences. One of the best examples of this is invasive species, which is the primary focus of my research. Invasive species are introduced through trade and travel, each of which brings large benefits to society. In contrast, the impacts of invasive species are extremely detrimental to society. The degree to which human societies can protect agricultural and natural lands, human and animal health, and beneficial economic systems in the future will depend in large part on our ability to manage the introduction and spread of invasive species.
As well as being of practical importance, the study of invasive species offers great opportunities to test fundamental ecological theory. Invasive species enter ecosystems rapidly and often lead to very large short-term changes. When viewed as 'natural experiments', invasions thus offer the opportunity to investigate changes in the basic structure and function of ecosystems, and in how those changes impact human society. In particular, these changes offer researchers the type of perturbation that allows the nature and magnitude of environmental services to be determined. Much of my research begins by taking the ecological impacts of invasive species and investigating how those impacts transmit into human economic systems. Importantly, this research involves placing explicit economic values on ecosystem services and then testing whether currently available methods for preventing and controlling invasive species are economically rational.
In all of my research I aim to explore fundamental ecological theory in ways that are relevant to the information needs of environmental managers and policy makers. This has lead to a number of collaborations with agencies that are working to prevent the arrival of future invaders. In particular, I worked on an advisory panel to the Chicago Department of Environment as they developed and implemented a list of species that are now prohibited from trade. I am also working with agency scientists, NGOs and trade representatives in Indiana to develop and implement a screening system for non-native aquatic plants in the nursery trade, and with the National Invasive Species Council.