About This Project
What is this crowdmapping venture all about?
This project was conceived as part of a graduate research fellowship awarded to Chris Whitney, a PhD student at the University of New Hampshire. This research project aims to understand the role that beaver ponds and other freshwater (fluvial) wetlands have on surface water quality. More specifically, the intent is to understand the impact of these aquatic ecosystems on nutrient, sediment, and greenhouse gas fluxes at the river network-scale.
It is hypothesized that these beaver ponds and fluvial wetlands retain both nutrients and sediments while releasing more greenhouse gases relative to channelized streams. Retention of nutrients, such as nitrogen, is beneficial as too much reaching the coast can lead to algal blooms that have the potential to reduce or remove the amount of oxygen available to other organisms. The Gulf of Mexico dead zone is a well-known example of this. Beaver ponds slow down the flow of water, allowing for greater contact of nutrients to the substrate where biological activity removes them from the water column. Rates of biological activity can also be higher in beaver ponds which further increases the potential for nutrient retention.
Retention of sediments is less desirable. As salt marshes struggle to compete with sea level rise, they need all of the sediments available to them. Rivers used to be a substantial source of sediment but since the increase in numbers of human-made dams, behind which are reservoirs that act like sinks for sediments, this release of sediments to the coast has dwindled. Since the resurgence of the beaver population in MA starting in the early 21st century, there has also been an increase in the number of small beaver ponds. It is possible that the numerous, small headwater beaver dams can retain a substantial fraction of sediment that would otherwise reach the coast as well.
The increased potential for the release of greenhouse gases is also a less than desirable effect of beaver ponds. The release of carbon dioxide, methane, and nitrous oxide is a result of the respiration of organic matter. Like sediments, beaver ponds (as well as reservoirs, fluvial wetlands, and other non-channelized water bodies) are a sink for organic matter. This respiration of the accumulated organic matter leads to increased release of greenhouse gases. Beaver ponds also contact forest soils that would otherwise be disconnected from the river network. This provides additional sources of fresh organic matter for bacteria to decompose.
Why is it important to know about beaver activity?
As mentioned above, beaver ponds have the potential to have a dramatic effect on ecosystem processes. This is important because since beaver conservation efforts began in the mid-1990s, there has been a recovery in the beaver population and as a result, an increase in the number of beaver ponds. Beaver are known as ecosystem engineers and change the landscape to suit their needs. This means that as their numbers increase, we can see more beaver habitat being built. The construction of upstream dams may slow or stop the flow of water downstream, causing individuals to more to other locations, continuing the cycle of dams being built and abandoned.
Needless to say, the beaver-influenced landscape is dynamic. Having an up to date inventory of beaver activity can help to understand just how dynamic beaver-created wetlands are in flat, coastal watersheds like the Parker and Ipswich. Measurements of nutrient, sediment, and gas fluxes began in 2014 and are ongoing and will be used in conjunction with the dynamic inventory of beaver pond abundance, distribution, and location to understand how they have influenced riverine processes and how that may change in the future.
Check out the 'Data Layers' and 'How to Help' tabs for more information.
Any questions or comments can be submitted on the 'Contact Us' tab or emailed to piebeaverponds@gmail.com.
