Why We Monitor River Ecosystems

Rivers and streams have a wide array of diverse and unique habitat types that support many different and often sensitive species. These species have evolved to a specific range of environmental conditions and processes. Changes that occur on the landscape as a result of human activities (e.g. groundwater infiltration) result in a change to the form, structure, quantity and quality of habitat in rivers and streams. This puts aquatic species at an increased risk of potential harm because it alters the range of ecological processes to which native aquatic species have evolved. To promote early detection, monitoring focuses on the most sensitive species, the ones that respond first to change. The degree of change acceptable to the community will be decided through societal processes and through planning exercises such as watershed or fisheries management planning.

The species that are not immediately eliminated through the direct effects of landscape change (e.g. sediment discharges, chemical spills) can be gradually weakened through isolation, insufficient number, and degraded water quality. Species that have specific ecological sensitivities or are naturally rare, are at particular risk of being eliminated over time. Aquatic invasive species and new diseases (e.g. round goby, Viral Haemorrhagic Septicaemia  (VHS) pose new additional threats to our aquatic ecosystems and can be very successful where native species have been weakened or eliminated. The spread of invasive species is currently considered one of the most serious threats to biodiversity in our river and streams.

In order to manage and protect the components of or our rivers and streams to support healthier ecosystems, biological knowledge and understanding must be more fully developed. To this end the monitoring that Citizen Scientists conducts examines change over time at site specific locations within the watershed. This monitoring work examines habitat conditions from the headwaters to the lower reaches of the watershed, and involves the monitoring of many components of the river ecosystem in order to paint a richer picture, and quantify the changes that take place. Citizen Scientists works to monitor changes in species numbers, composition and population structure at the monitoring sites, and then links the observed changes back to the alteration of ecological processes that result from change to landscape form (i.e. meadow to subdivision). The understanding developed through monitoring will be used to help make improved management decisions about landscape activities that will help to maintain healthier rivers and streams.

The components of aquatic ecosystem integrity that Citizen Scientists focuses on include:

• The health of the aquatic ecosystem;

• The aquatic ecosystems ability to deal with stress or change;

• The ability to maintain self-organizational processes;

• Biodiversity.