Rewriting the ecological histories of rivers

An interesting article this week at Yale Environment360 profiles recent research on river ecosystems.  As Jim Robbins emphasizes, even rivers that have never been dammed can be vulnerable to the many other ways in which human activities affect rivers, with the ultimate consequence of compromising rivers' "immune" systems, making them more vulnerable to other impacts, such as exotic parasites.

The effects on rivers of human activities can be very subtle -- in fact, often subterranean, as when the essential interactions between river water and accompanying groundwater flows are interrupted, thereby damaging a river's ability to change and renew itself and its diverse habitats.  These changes may also often only become apparent after decades of incremental manipulations.

There are several interesting connections between this scientific perspective, and our understanding of the environmental history of rivers.  It adds a new dimension to how historians view rivers as single, integrated systems: that is (using Richard White's term), as organic machines.  These "machines" operate as much below the surface, as above.  It also underlines the need to draw on these insights when understanding the history of rivers, so as to make sense of ecological changes, such as the spread of parasites, that can have consequences for humans and other species.  And finally, the nature of these ecological changes -- as the product of transformations occurring over decades -- highlights the value of an historical perspective on these rivers.  Yet another illustration of how historians can contribute to scientific efforts to understand moving water.