The bright side of linking science and management in large river ecosystems: The Hudson River case study

Large river ecosystems (LRE) are important components of global cycles, influence large parts of the earth's surface, and provide many services in support of human civilization. However, understanding their condition, functioning, and trajectory of change is difficult in part due to their scale and diversity of forcing factors but also due to multiple and potentially conflicting human uses. Although these challenges are generally applicable and probably true to some degree for any large river ecosystem, there are also attributes of LRE that foster scientific understanding, can lead to knowledge-based management, and may catalyse their interaction. The absolute size of LRE means they will be complex, unique and the water quality, physical character, or habitat availability at any particular point may be the result of drivers acting further up the basin or legacies from previous times. On the bright side however, their absolute size also means there will be existing information on many important features, not least land cover and hydrology. Moreover, it is highly likely there will be a sizeable human population in the basin that derives some benefits from the river even if just in a narrow anthropocentric fashion and so there will be some motivation for understanding characteristics and potential change. Large size also suggests that the LRE will be viewed (perhaps with some basis in law) as a national or regional resource making it (at least nominally) worthy of study and management. I provide some examples of how science and management of the Hudson River in New York, USA, have benefitted from some of these perceived difficulties perhaps offering optimism for application in other systems.