Alberta Innovates Technology Futures, Apophenia Consulting, University of Alberta, and Stantec
February 2014
# 09-9194-50 / 13-AU-ERPC-04
Executive Summary
A new method to assess cumulative effects on biodiversity
We used information from the Alberta Biodiversity Monitoring Institute (ABMI) on birds, plants, human footprint, and vegetation, plus information from Dr. Bayne on birds, to test a new method for determining cumulative effects on biodiversity in northeast Alberta, Canada. This new method uses as much of the existing information as possible, and incorporates empirical modeling and mapping techniques to highlight changes in wildlife and biota in response to current human footprint (i.e., present cumulative effects), and to predict future cumulative effects as development continues. We tested the new method for a small suite of biodiversity indicators. Cumulative effects assessment for other biotic indicators and for other environmental aspects (e.g., soil, hydrology and air), were beyond the scope of the present project.
We created models that described empirical relationships between current species relative abundance measures and current vegetation / human footprint. We then applied the models to spatial vegetation / human footprint in a Geographic Information System (GIS) to map cumulative effects that have already occurred in one regional and one subregional study area in northeast Alberta. We also simulated human footprint expected in the region 25 and 50 years into the future to predict future cumulative effects. Projections of human development into the future were uncertain because future social, economic and environmental constraints are unknown, and may have significant implications for resource development and the resulting habitat changes that will be created. As such, predictions of future cumulative effects must be interpreted with caution.
As a coarse filter assessment of cumulative effects on biodiversity, we described the changes to vegetation that have already occurred as a result of existing human footprint in the region, and predicted future changes to the vegetation based on the simulations. We applied existing cumulative effects models for caribou (Rangifer tarandus) to the vegetation and human footprint maps to highlight cumulative effects for a species of high management concern. We created models and maps for black-throated green warbler (Dendroica virens) to describe cumulative effects for a species that was expected to be negatively affected as old forest becomes less abundant in the region. We extended the modeling and mapping beyond the species level to describe cumulative effects for species groups (i.e., forest plants, old forest birds, native plus introduced weedy plants) that were expected to be heavily affected by industrial development. Finally, we showed how modeling and mapping could be extended to assess cumulative effects for biodiversity in general. These empirical models and predictive maps add scientific rigor and spatial context to cumulative effects assessment of biodiversity.
The maps we created for species, species groups and biodiversity predict the cumulative effects expected in each quarter-section throughout the study area under current and projected future
conditions. These maps show the spatial variation in cumulative effects, and allow resource managers to better understand the amount and geographic location of cumulative effects that have already occurred and that are predicted to occur in the future. Maps of cumulative effects can be summarized at any spatial scale by averaging information across the area of interest. The maps can also be used to identify locations where developments are expected to alter species abundance greatly and where management would be most effective at mitigating those effects. We think this new method is more informative than the methods presently used to assess cumulative effects on biodiversity because they are spatially-explicit and based on empirical models using existing, freely-available datasets.Coarse filter assessment – disturbance of vegetation in the regionUnder current conditions, 6% of the regional study area has been converted to human footprint, with this expected to grow to 11% in the next 50 years. Approximately 50% of the footprint was due to forest harvest, with seismic lines, well sites, and pipelines accounting for 10-15% each. Three vegetation types – grassland/herbaceous, deciduous and mixedwood forest – had disproportionate amounts of conversion to human footprint. Forest harvesting is focused on upland stands of trees, and as expected old forest was often converted to cutblocks. It was not clear what caused the disproportional conversion of grass/herbaceous vegetation to human footprint, but these habitats may have been targeted for development by energy companies to avoid forest resources. As a coarse filter measure of cumulative effects on biodiversity, however, disproportionate conversion of grassland/herbaceous, deciduous and mixedwood forest suggests that species relying on these habitats may be disproportionally affected by human development in the region. Vegetation recovery in disturbed areas was not accounted for in the present study, and many native and non-native biota are expected to recolonize and use disturbed areas as the vegetation recovers.Based on the present dispersion of human footprint through the regional study area, edge effects were common and greater than 50% of the region was within 200 m of human footprint. Only 1% of the region was presently greater than 2 km from human footprint and thus isolated enough to be considered true wilderness. The magnitude of edge effects on biodiversity is poorly understood at present.Cumulative effects assessment – species, species groups, and biodiversity Cumulative effects on caribou and black-throated green warbler were higher than those for species groups or biodiversity in general. Caribou was of particular management concern in northeastern Alberta (Alberta Sustainable Resource Development 2011, Environment Canada 2012) and maps of current habitat suitability for caribou supported this conclusion. Based on Environment Canada’s model for caribou habitat suitability, only 32% of regional study area was currently suitable for caribou use. With continued development, only 15% of the regional study area was expected to provide suitable habitat for caribou 50 years into the future. Maps of habitat suitability provide a strong management tool by highlighting locations that were presently suitable for caribou, and identifying areas where active reclamation of human footprint could be done to increase habitat suitability for caribou. The effectiveness of habitat reclamation for caribou, however, has not been tested and if reclamation is implemented monitoring will be required to determine whether caribou populations recover.
For black-throated green warbler, old-forest birds, weedy plants, forest plants and biodiversity in general we found much lower cumulative effects in the regional study area than that found for caribou; intactness was currently above 85% for all of these indicators. Cumulative effects for black-throated green warblers were projected to increase over time as development continued, and the species was predicted to decline to 72% intactness 50 years into the future. Cumulative effects for species groups and biodiversity in general were projected to increase less than for caribou and black-throated green warblers; for all of these groups intactness was projected to remain above 80% for the next 50 years. For all indicators cumulative effects were projected to vary spatially, with relatively high cumulative effects in quarter sections containing abundant human footprint and lower cumulative effects in quarter sections with low or absent human footprint.Cumulative effects were lower for forest plants and overall biodiversity than for old forest birds and weedy plants. Forest plants and total biodiversity included many species that were habitat generalists, and thus not surprisingly were less affected by the habitat/vegetation changes that accompany industrial development. However, cumulative effects were present for all species groups, and were predicted to increase as development increased over time. To provide a balanced picture of cumulative effects on biodiversity, it will be important to include high profile species, specialist species groups and generalist species groups – these specialists are expected to respond most strongly at low levels of resource development whereas generalist species respond as the amount and extent of development increases.Differences among spatial scalesFor all species and species groups, cumulative effects were slightly lower at the scale of the regional study area than the subregional area because development was slightly higher in the subregion. However, in the long term, increased human development is expected throughout the whole region. It will be important to track cumulative effects at a variety of spatial scales to assess incremental cumulative effects over time.Pilot of the new methodThe new method we developed for assessing cumulative effects on biodiversity improves previous approaches by: i) integrating assessments within a region so that local project-scale evaluation and regional land-use planning and management use a common suite of information, ii) facilitating collaboration and cost sharing, with all developers working together to produce a single assessment for the region, iii) ensuring that consistent high-quality information is produced for all areas within the region, iv) using all the available species and landscape information for the region to produce a scientifically robust assessment of cumulative effects on biodiversity, v) avoiding duplication of effort since the assessment can be completed once as a unit rather than as a number of piecemeal and potentially overlapping assessments, vi) facilitating regular and rapid updating of cumulative effects as new developments occur, vii) ensuring that stakeholders can access cumulative effects information from a single location for all developments in the region, and viii) having assessments done by a neutral third party that focuses on doing a rigorous unbiased evaluation.
There would be value in piloting the new cumulative effects assessment method to evaluate how it can support the evolution of policy, understand the costs to doing an integrated regional cumulative effects assessment for biodiversity, and assess the benefits/weaknesses of the resulting information. A shift towards conducting cumulative effects assessment as a collaborative effort would be a significant change to the EIA process in Alberta.
All cumulative effects assessments are predictions and long-term monitoring is required to test whether these predicted effects are real. Monitoring is the true test of whether the modeling assumptions are met, and through monitoring it will be possible to adaptively improve assessment and management over time.