Riparian Function and Management of Small
Streams
The Riparian Study Team, comprised of Ministry of Forests Regional Research, P. Beaudry and Associates Ltd.; Department of Fisheries and Oceans, Science Branch and Canadian Forest Products Ltd. are working on describing and quantifying natural stream functions in small streams in the Prince George Forest District. The project was initiated in the 2001 field season to determine if harvesting to the Prince George District Manager’s Policy for “Maintaining the Biological and Physical Attributes of S4, Small Fish-bearing Streams” maintains the necessary ecological attributes for healthy fish habitat.
The Riparian Study Team is using an active adaptive management approach. Adaptive management is an “approach for learning from our actions, improving management and accommodating change”. This approach allows for objectives and actions to be adjusted to reflect new information and to achieve desired outcomes. Initially, the Riparian Study Team will establish an understanding of natural stream functions of small streams in sub-boreal forests. The Team will subsequently look at changes in the natural stream functions over time caused by various forest harvesting practices within the riparian area. This will improve our understanding of the important roles, processes and attributes of small streams in a watershed context, aid in the development of riparian and stream indicators for sustainable forest management and adaptively test alternative riparian management strategies.
The Riparian Study Team’s initial objectives are to quantify the temporal, geographic and among stream variations. The streams will be located in geographically distinct forest types to be able to compare variations in vegetation, local climate and terrain. The experimental design is based on a Before-after-control-impact paired design (BACI-P) described by Schwarz (1998[1]). This type of design has at least two types of sampling (before and after impact) in areas (treatment and a control) with biological and environmental variables being measured in combinations of time and space. For each stream (both treatment and control) the following factors will be measured over space and time:
- late summer/fall temperatures,
- channel morphometrics,
- substrate composition,
- erosion sources,
- litterfall, shade, solar radiation exposure,
- benthic invertebrates,
- periphyton biomass,
- water chemistry,
- nutrients,
- woody debris,
- downstream export of organic material, and
- downstream invertebrate drift.
The measurements will occur over a period of 2 to 3 years prior to harvest to capture and understand the natural variation in stream functions.
The description and quantification of natural stream functions will increase the understanding of the critical components of the ecology of small streams in the sub-boreal forests. Refinement of practices based on the increased understanding of the functions of small streams will result in improvements in riparian harvesting practices to protect critical small stream functions.
In 2001 methods to monitor the natural stream functions were refined and paired plots were established in several locations to collect baseline data. Three sites are currently the focus of intensive ecosystem monitoring: 1) Bowron - SBSvk 2) Tagai - SBSdw2 and 3) Chuchinka –SBSwk1. The Chuchinka block will be harvested according to the DM policy for S4 streams (current best management). This block is scheduled for harvesting in winter 2002 and will have 2 years of pre-harvest data. The control for this block is an upstream reach of the stream in an unharvested area. The other two sites are currently being used to describe the natural ecosystem functions in undisturbed ecosystems. Additional streams within Canfor’s operating area, will be identified in 2002 to establish study blocks over a range of forest types and ecosystems. These blocks will be identified by Canfor as “research blocks” and used to test innovative riparian management practices. Canfor will control the prescriptions and layout of these blocks in an effort to provide optimal conditions for our experimental designs.
The goals of the Small Stream Riparian Study are to:
- Increase our understanding of natural functions of small streams in different forest types in sub-boreal forests.
- Identify specific knowledge gaps in the management of small streams
- Identify critical components of small streams and the adjacent riparian areas in sub-boreal forests that maintain stream productivity and protect other stream values.
- Contribute to the identification of key indicators of sustainable riparian forest management.
- Assess the current riparian management practices (study sites initiated in 2001 will be harvested with the DM S4 stream policy).
- Assess new best management practices by using innovative prescriptions on the streams that will be monitored.
- Compare different riparian management practices and their effects on aquatic ecosystems.
The Riparian Study Team will produce operational summaries and scientific reports for this project. It is also the intent of the Riparian Study Team to organize field workshops for operational foresters and practitioners to disseminate the results.