Wetland hydrology in an agricultural landscape: implications for biodiversity

Abstract

Intensification of agricultural practices, such as groundwater extraction, stream flow regulation and vegetation clearing often leads to a reduction in both the number and hydrological diversity of wetlands in a landscape, reducing the amount of habitat available for many species. Remaining wetlands are often hydrologically homogenized and far less variable than under natural conditions and as consequence many species are no longer able to persist in the landscape over the long term. However, many studies only observe wetland hydrology at relatively small spatial and temporal scales. Consequently, there is little knowledge about wetland hydrology at the broader landscape scale and how it may change under changing climatic conditions. To help address this knowledge gap we analyzed hydrological data from 251 wetlands across 3 regions over a 17 year period from 1987 to 2005 to examine temporal changes in wetland hydrology in an agricultural landscape. This research investigated changes in the hydrological nature of wetlands in an agricultural landscape between two time periods from 1987-2005 and 2000-2005 (dry climatic period) to examine how wetlands may change through time, particularly under changing climatic conditions. In the recent time period, there was a significant change in the number of wetland hydrology groups represented in some of the landscapes. In the recent dryer period there was an increase in the number of frequently dry and wet wetlands and a reduction in the number of wetland representing the intermediate hydrological range. Changes in the number of wetland groups represented could have implications for biodiversity across the landscape if climate change intensifies the patterns observed.