The words ‘marsh’, ‘bog’ and ‘swamp’ often conjure up images of a dank and dreary wasteland, something akin to a post-apocalyptic landscape. However, ‘wetlands’, as these systems are more commonly coined in the research world, are among the most productive and important ecosystems on the planet.
February 2nd 2020 marks World Wetlands Day, a day dedicated to raising global awareness about the vital role of wetlands for people and our planet. This day also marks the date of the adoption of the Ramsar Convention on Wetlands in 1971. The United Nations (UN) mandated convention on Wetlands is an intergovernmental treaty that provides the framework for national action and international cooperation for the conservation and wise use of wetlands and their resources.
The theme for World Wetlands Day 2020 is Wetlands and Biodiversity, which aims to highlight wetland biodiversity, its status, why it matters, and to promote actions to reverse its loss. Globally, wetlands provide a home and/or breeding ground for 40% of all species. The combination of climate, topology, geology and the movement and abundance of water, shape each wetland into a unique system, ultimately determining the fauna and flora we see. Worryingly, the latest estimates show that wetlands are disappearing three times faster than forests, resulting in both diversity loss and direct impacts on people.
In Canada, wetlands make up 14% of land cover, however this number used to be a lot higher. In southern Ontario, 68% of the original wetlands have been converted from their natural state to support alternative uses such as agriculture. Most of Canada’s existing wetland systems can be found in the north, with the Peace-Athabasca river delta in Alberta being one of the largest. To be able to protect Canada’s remaining wetlands, we need to understand how to effectively monitor the biodiversity and subsequent health of different wetland systems.
Biomonitoring 2.0 for Wetland Health
The Peace-Athabasca river delta, that lies within Wood Buffalo National Park, has been the focal system for a large-scale biodiversity study since 2011. University of Guelph, in collaboration with Environment and Climate Change Canada (ECCC) and Parks Canada has been analysing the richness of species, primarily aquatic macroinvertebrates, using DNA metabarcoding. Samples have been collected over the last 9 years following the protocol developed by Environment Canada’s Canadian Aquatic Monitoring Protocols (CABIN) for Wetlands.
Following on from this long-term study, the STREAM project (Sequencing The Rivers for Environmental Assessment and Monitoring) typically involves the collection of benthic river samples through community-based monitoring across Canada, to detect macroinvertebrates (often larval forms). This approach uses DNA metabarcoding to provide an overall assessment of freshwater health. Realising the importance of wetland systems, STREAM is collaborating with community groups and organisations to collect benthic wetland samples.
Slocan River Streamkeepers: Wetland Restoration
One of the community-based organisations that collaborated with STREAM in 2019 was the Slocan River Streamkeepers, a non-profit society founded in 2003, that aims to protect and restore the aquatic and riparian ecosystems of the Slocan River (British Columbia, Canada). In collaboration with Darcie Quamme at Integrated Ecological Research (IER), the Slocan River Streamkeepers aim to conduct community-based wetland restoration assessments across Winlaw and Appledale (BC), using taxonomic and DNA-based methods.
In 2017, a wetland restoration project at Crooked Horn Farm in Winlaw was completed by Slocan River Streamkeepers, which involved transforming a 0.5 Ha area into a flourishing wetland system with the aim of providing habitat for a diversity of wildlife including benthic invertebrates.
STREAM in the Slocan
Previously, in collaboration with IER, aquatic macroinvertebrates collected from Crooked Horn Farm before and after restoration were identified by a taxonomist along with 62 samples from other wetlands. However, in 2019, benthic kick-net samples from this wetland and eight other sites collected for DNA and analysed by STREAM.
Results from a total of nine wetland sites revealed similar proportions of key taxa when compared to taxonomic identification, namely orders Diptera (flies), Odonata (dragonflies and damselflies) and Trichoptera (caddisflies). A particularly interesting finding was exclusive detection of the common whitetail dragonfly (Plathemis lydia) in STREAM samples from the Crooked Horn Farm wetland, which corresponds with visual surveys of adult dragonflies that have identified this species being a dominant at this site in 2018.
In addition to the common whitetail, a variety of other Odonata were detected in STREAM samples, including the spotted spreadwing (Lestes congener), four-spotted chaser (Libellula quadrimaculata) and downy emerald (Cordulia aenea). Wetlands provide vital habitats for Odonata, as they require flooded habitats to breed and mature. In Canada, Odonata are considered an important indicator of intactness and biodiversity richness of wetland systems, as they are sensitive to the effects of cattle grazing and wetland drying.
Overall, the wetland restoration project at Crooked Horn Farm has been a success, with numbers and diversity of birds, mammals, amphibians and insects ever increasing. Providing this unique habitat for macroinvertebrates is particularly important, as they provide a food source for other wetland species and groups of taxa, such as Odonates, act as biological indicators for wetland health and productivity.
Monitoring aquatic macroinvertebrates can be achieved rapidly and accurately using the STREAM DNA-based approach, with the data produced being compatible for comparisons with taxonomic data previously collected. For this World Wetlands Day and many others to come, using this effective monitoring approach for wetlands allows for detection and suitable addressing of changes in biodiversity, particularly in the face of climate-related impacts on wetlands.
Written by Dr. Chloe Robinson