Modelers and field biologists—an essential team
Computer simulation models of how we think the world works are imperfect; however, they can be useful as aides for conservation planning. Biologists still have to do the hard thinking—concocting arrays of program options that make sense. For example, will a proposed management action address those factors limiting local duck production? Which fixes are practical given regional soil and climatic conditions? What options are likely to be of economic interest to private landowners or a good policy match for government priorities?
What computers do is remove the burden of endless calculations and thereby allow managers to consider and compare complicated combinations of actions across landscapes and over time, and they greatly accelerate the speed with which planners can play "what if?" games.
DU's new decision support system (DSS) represents another leap forward. Dr. Karla Guyn, head of the DU DSS development team, notes that, "By synthesizing our current knowledge about landscape factors affecting duck production, DSS helps ensure that conservation programs are targeted based on the best scientific information available."
DSS is also proving useful for the design of public policy. The model's results already have helped shape DU's approaches to Canadian government agencies and public forums where DU advocates its vision for a sustainable prairie landscape.
There is no better basis for targeting DU's work today than the knowledge and ideas incorporated in these production models. The value of any planning tool, however, depends crucially on the soundness of the assumptions that underpin it. Managing adaptively means, among other things, testing key assumptions that, if wrong, could drastically change conservation outcomes. For instance, while the density of wetlands in spring largely determines the number of birds settling to breed (and also affects nesting effort, duckling survival, etc.), the amount of permanent vegetation in a landscape seems to impact the likelihood that nests hatch. Such a relationship may exist because more grass means predators are less likely to detect duck nests that are widely dispersed, or because the amount of vegetation affects the mix and density of predators present on a landscape. Regardless, for upland-nesting ducks like mallards, data on wetland abundance and land cover together provide DU planners with advice on where to deliver which kinds of conservation actions.
Our understanding of how landscape features affect ducks has improved recently, but the quest for better knowledge continues. For example, the rate of gain in nesting success with increases in permanent cover may be greater in grassland regions than parkland regions. If verified, this would have important ramifications. Consider also how dynamic wetland conditions are in the grassland-pothole region, cycling from years of extreme wetness to severe drought. Layer on top of that changing land-use resulting from changes in farm programs and commodity prices, fluctuating populations of small mammals such as voles and mice (alternative prey for duck predators), and varying levels of diseases such as rabies and mange that affect predator numbers. With this variability, conservation actions that are effective in one area may not be in another, and activities that produce the desired results one year may not be successful the next. According to Dr. Jim Ringleman, head of conservation programs in DU's Great Plains Regional Office, "The million dollar question, really, is how to achieve desired results of conservation programs a high proportion of the time amidst all this variation and complexity."