Protecting waterfowl in the Riverwalk wetlands

Posted

2021/08/wetlands-Barry-Knott-Mallards-on-Riverwalk-1024x683.jpg
Photo courtesy Barry Knott
Mallard ducks float on a Riverwalk wetlands pond.

By Josh Pike

Pagosa Wetland Partners

Waterfowl, including ducks, geese and swans, are some of the most prized wildlife in the area. Often seen on ponds, wetlands and riverbanks, waterfowl like Canada geese and mallard ducks are among the best-known wildlife in Pagosa Springs. 

Waterfowl utilize a wide range of habitats in the area, including the San Juan River and local lakes, such as Lake Pagosa. One of the richest and most diverse waterfowl habitats in the area is the Riverwalk conservation area and its geothermally fed wetlands. The diversity of plants supported by the geothermally fed year-round open water make for an ideal waterfowl habitat during migration or otherwise.

As development and tourism expands in Pagosa, it is important to consider how to effectively conserve and enhance our wetland environments, including our waterfowl populations. These environments are important ecological resources and natural attractions for local residents and tourists. Protecting them is an obvious priority. 

The Town of Pagosa Springs recognizes the social, business and environmental importance of our downtown wetlands in its 2018 Comprehensive Plan. The plan speaks directly to the need and intent of the town to “Consider adopting local wetlands regulations into the LUDC to ensure wetland areas are protected, or if disturbance is unavoidable, the impacts are minimized and mitigated.” — 2018 Comprehensive Plan, Goal N1, page 9. 

A preliminary approach to protecting the wetlands is to focus on the needs of a single key group of species, such as waterfowl, and build protections around them. Put simply, we consider what exactly waterfowl need in their environments and design policies to protect these key characteristics. While this process is comprehensive in considering all elements of a wetland, it is a useful tool for conceptualizing wetland protections and the lists of protections generated by this process can be surprisingly complete.

Science informs us that waterfowl require three primary things from their wetland environments: 1) consistent water quality and quantity, 2) diverse and high quality vegetation, and 3) a minimum of disturbances. Focusing around these three elements is a good starting point. 

Waterfowl are highly reliant on predictable and sufficient water in the wetlands they frequent. Not only do many waterfowl feeding behaviors, such as diving or dabbling, rely on water, but most waterfowl food sources, such as algae, water plants and aquatic invertebrates, only exist when water levels are reasonably consistent. Securing the warm-water inflows into our wetlands from inadvertent disruption is a good starting point in protecting our downtown wetlands. 

The quality of the water is also important. Waterbirds can become poisoned by high levels of toxins from various sources such as parking lot runoff, sewage, industrial waste and the like. Protecting the wetland requires enforceable measures to ensure that neither water quality nor quantity is unnecessarily compromised. Such measures frequently include monitoring of water quality, water catchments to limit the runoff of surface water from nearby pavement and parking lots and, in the case of the geothermal wetlands, planning to ensure that inadvertent geological changes from development projects do not disrupt the water flows and even the temperature of water going into the wetlands.

Waterfowl also need the wetlands to contain diverse and highly nutritious vegetation. Plants are a core part of these birds’ diets and a wider diversity of plants helps accommodate more bird species by ensuring food is available throughout the season. Without plant diversity, the wetland may only contain plants appropriate to limited bird species or may only provide food through part of the season. 

A primary threat to wetland biodiversity is the presence of invasive plant species such as the Russian olive tree, which can be found along the Riverwalk. Such species may spread rapidly, force out native species and reduce the range of native food sources available in the wetlands. Further, invasive species may be more susceptible to or tolerant of wildfires than native species. Many invasive species are either toxic or of low nutritional value, meaning their prevalence does little to contribute to the nutritional value of the wetlands.

Managing invasive species requires a range of measures, including frequent vegetation surveys and regular targeted removal of invasive plants. Eradication before they become too entrenched is key. Such management is crucial to maintain the value of a wetland for future generations. 

Finally, waterbirds need insulation from frequent disturbances in the surrounding environment. Disturbances can include nearby traffic noise, obtrusive nighttime lighting and too-close human encroachment. In addition to the stress such disruptions cause in birds, such disturbances may reduce their reproductive success as well as that of other animals. 

A proven measure to reduce nearby wildlife disturbances are setbacks or buffers which designate a minimum proximity, often 200 feet or more between buildings/roads and the edge of flood planes or wetlands. Such setbacks cannot completely eliminate human disturbances, particularly in wetland areas used for outdoor recreation, but they are an effective measure for mitigating the impact of ongoing development and human usage. Setbacks also mitigate contaminated street and parking lot runoff from entering the wetlands by allowing the buffer space to naturally filter out pollution.

While this suite of protections is tailored to waterbirds, the measures mentioned in this article are also effective in protecting other wetland species. Because of how interconnected wetland plants and animals are, protections for one species protect others as well. The details and implementation of such protections are complex and require thoughtful deliberation. However, a simple thought experiment focusing on waterfowl is a good way to begin thinking about broader wetland protections. 

If you want to get involved in protecting our local wetlands or learn more about them, please contact Pagosa Wetland Partners at pagosawetlands@gmail.com. Additionally, you are invited to join one of our Riverwalk Wetland Tours, educational tours of the Riverwalk wetlands that occur every week on Tuesday at 7 p.m. and Friday and Saturday at 8 a.m., starting at the Native Plant Garden in Centennial Park.