Process-Based Stream Habitat Restoration in Downeast Maine
Project SHARE is non-profit, 501(c)(3), with a mission focused on river habitat restoration in Downeast Maine. Project SHARE’s habitat restoration program is based on a process based, focus area approach where priority focus areas are identified with the assistance of state and federal fisheries biologists. A threat assessment of the focus area is linked to historic land use practices. The principle land use activities in the project focus areas are historic commercial forestry and modern commercial forestry. Historic commercial forestry involved log drives using the river and stream network as the principle transport mechanism. The log drive era left a legacy of remnant dams and associated reservoirs and reduced habitat complexity due to the removal of boulders and large wood from stream channels to facilitate the log drives. Recent field assessments indicate that main stem water temperature is elevated and there is a reduced interaction of the river with its floodplain. Each of these legacy impacts negatively affect natural stream processes, cold water fish habitat and flood resiliency. Modern commercial forestry relies on a recently developed road system to transport logs to market. The modern road system includes a network of undersized culverts as the principle infrastructure for crossing headwater streams. As a result, stream connectivity is severely impaired, reach specific habitat alterations are apparent, and fish passage to upstream habitat and cold water refugia is restricted.
Habitat impacts that have been identified in the project watersheds include:
- loss of connectivity due to undersized round culverts at road/stream crossings,
- elevated water temperatures in part due to over widened channels and legacy reservoirs associated with remnant log drive dams,
- loss of habitat complexity due to the removal of large wood and boulders to enhance historic log driving
- loss of connectivity between the river and its associated riparian buffer due to removal of habitat complexity elements.
Process-based Restoration and Resiliency
Process-based habitat restoration provides a holistic approach to river restoration practices that better addresses primary causes of ecosystem degradation (Roni et al., 2008). Historically, habitat restoration actions focused on site-specific habitat characteristics designed to meet perceived “good” habitat conditions (Beechie et al. 2010). These actions favored engineering solutions that created artificial and unnaturally static habitats, and attempted to control process and dynamics rather than restore them. By contrast, efforts to reestablish system process promote recovery of habitat and biological diversity. Process restoration focuses on critical drivers and functions that are the means by which the ecosystem and the target species within it can be better able to adapt to future events, such as those predicted associated with climate change. The critical elements missing from the project area that will be addressed by the actions identified in this proposal are: reduced connectivity due to undersized round culverts and remnant dams and instream large wood which functions as an element of habitat complexity. Corrective actions that address these areas will catalyze the restoration of natural stream processes which are the basis for improving watershed resiliency.
Resiliency is the ability of an ecosystem or community to absorb, recover from, or more successfully adapt to adverse events such as extreme weather or long-term changes in environmental conditions. Watershed resiliency is a current topic for discussion relative to successful restoration of freshwater habitat. Inaccessible, lost or degraded habitat from past land use practices are identified as major contributors to declines of both Pacific and Atlantic salmon populations. Faced with threats due to climate change, the prospect of successful restoration of species-at-risk becomes even more tenuous in watersheds where natural stream processes are impaired and resiliency is diminished. Understanding how natural processes have been fundamentally altered by human activities and how those activities can be reversed to promote salmonid recovery is a significant first step to a successful habitat restoration effort (Bisson et al. 2009).
Project SHARE’s Habitat Restoration Program
SHARE’s success begins with collaboration:
- land owner relations based on trust and respect
- collaborating with and leverage the capacity of other NGOs, state and federal agencies
Over the last fourteen years SHARE, in collaboration with state and federal agencies, landowners, and nonprofit organizations, has developed a habitat restoration program with principal focus on the five Downeast Maine Atlantic salmon watersheds. We have identified threats to stream connectivity and function and opportunities to restore coldwater refugia and habitat, and conducted cooperative projects that removed those threats and restored connectivity and natural stream function. SHARE’s restoration program is based on a focus area approach.
- Step 1: Working with local biologists, we identify priority focus area, the sub-watersheds that are most productive for Atlantic salmon and brook trout productivity and have the greatest potential for a biological response.
- Step 2: Land owner support and involvement is essential
- Step 3: Conduct a threat analysis of past and present land use impacts
- Step 4: Triage restoration actions: connectivity actions are followed by habitat suitability actions
- Step 5: Aim as much capacity at the issues as you can to correct the problems.
- Step 6: Understand and learn from your mistakes.
SHARE’s restoration program takes the lead on each of these steps. Most of the landowners we work with are long time members of Project SHARE. They believe in what we are doing. Once we identify issues, SHARE takes responsibility for attempting to correct the problem. Watershed-scale threat assessments of the Narraguagus and East Machias Rivers have documented summer water temperatures in the main stem river approaching acute lethal levels for Atlantic salmon and brook trout. Remnant dams and associated legacy reservoirs are thermal barriers and heat sinks that contribute to higher river temperatures. Undersized culverts at road/stream crossings break stream connectivity and are barriers to fish reaching coldwater refugia. To date, we have improved stream connectivity at more than 200 Downeast Maine sites through dam removals and culvert replacements.
Negative impacts to instream habitat suitability for salmonids are another legacy of the log-drive era. An instream habitat assessment of the main stem of Maine’s Downeast coastal rivers has documented some of the lowest densities of large wood and wood structures in the United States. There is also evidence that boulders have been removed or fragmented by dynamite during the log drive era. A temperature assessment of the upper watershed documents summer water temperatures that exceed habitat suitability indexes for both Atlantic salmon and eastern Brook trout. Embededness surveys have documented that the lack of habitat complexity is contributing to a condition where spawning habitat is embedded. All of these issues are related and problematic on a landscape scale. SHARE has been working with state and federal biologists for a decade implementing large wood additions as a process based action for addressing habitat complexity. In areas that road crossing connectivity has been corrected, large wood additions become the next major project in our triage of actions.