Ranchers get frustrated when their efforts to improve forage yields and quality don’t benefit their cattle, because the neighborhood deer move in instead. But more wildlife may simply be moving in because there are fewer natural areas for them to live.
Imagine what happens when a river floods. Water seeks the easiest path, so it follows the riverbed. Higher ground remains exposed and dry. Bystanders gather on the riverbank to watch the driftwood float by. The water rises, eventually spilling over the riverbank and onto the surrounding floodplain. Cautious people leave the area. Others climb for a higher vantage point. Floodwaters begin to climb the valley walls. More people leave, but determined spectators climb to the top of the valley. High ridges along the top of the river valley remain exposed and connected. Eventually the rising water surrounds the high points, floods the lower spots connecting them and isolates the peaks from each other. This leaves small islands, overcrowded with sightseers questioning their decisions, checking their cell reception and scanning for helicopters.
A similar thing is happening with rangeland biodiversity. A growing global population is increasing the demand for food. Biofuel incentives support crop prices. Provided there’s enough sunshine and moisture, high prices make it tempting to cultivate marginal grassland to grow cash crops, and favorable crop insurance programs may make this look like a safe risk. As cultivated acreage expands, wildlife habitat shrinks. If too much forage and pastureland is converted to crops, the remaining islands of grass will be too small and disconnected from each other to support a functioning grassland ecosystem.
Agriculture and Agri-Food Canada’s Tim McAllister and collaborators from the Alberta Biodiversity Monitoring Institute, Universities in Egypt, Alberta, Toronto and Manitoba used Alberta as a case study to evaluate how continued conversion of hay and pasturelands to crop production would impact biodiversity (Divergent trends in structural landscape connectivity from historic and potential future grassland conversion in Alberta, Canada).
Click here to see more...