The scientists took data from detailed maps compiled by the U.S. Fish and Wildlife Service on three occasions over 27 years to map the actual changes in the marsh. Plugging all this into the model, they were able to chart a continuous change in each square over decades, and get a picture of how the marsh was evolving. To see what the marsh might look like in the future, the scientists plugged in different scenarios for climate, sea level, man-made structures and other factors. Tradition dies hard Ecosystem scientists argue for a shift away from just managing fishing toward a more comprehensive approach taking into account habitat, current flow and interactions with other species. But the new approaches face many obstacles.
Scientists violently disagree, for example, on the role of chaotic changes in fish populations.
Many fishery scientists say any chaotic changes will almost always be impossible to separate from other factors that aren't chaotic. That has the most immediate impact, and that's what the public is most concerned about,'' said Bradford Brown, director of the Southeast Regional Science Center of the Fisheries Service, who is also an expert on ecosystem modeling. But the biggest problem is history.