Taiga Shield Ecozone+ Evidence for Key Findings Summary
Theme: Science/policy Interface
Biodiversity monitoring, research, information management, and reporting
National key finding
Long-term, standardized, spatially complete, and readily accessible monitoring information, complemented by ecosystem research, provides the most useful findings for policy-relevant assessments of status and trends. The lack of this type of information in many areas has hindered development of this assessment.
Because the Taiga Shield ecozone+ is so lightly populated, there is little road access to much of the landscape, making research and monitoring difficult and expensive. Few ecological monitoring programs are designed for ecozones+ with limited access and a small population from which to draw volunteers. The consequence is a shortage of data about most aspects of the Taiga Shield ecosystems, from streamflow to animal populations. Understanding how ecosystems react to change – for example, under what circumstances accumulated changes trigger rapid (catastrophic) change or a gradual transition to a new stateFootnote 167 – is lacking. A problem for ecozones+ such as the Taiga Shield is how to recognize thresholds, given the lack of information available about the ecosystems themselves.
The Taiga Shield ecozone+ is characterized by a relatively large proportion of species at the edge of their ranges, whose abundances cycle, and/or are migratory. Predicting population trends within the Taiga Shield requires understanding the factors that limit the distribution of species. Both peripheral and migratory populations are vulnerable to environmental changes in the parts of their range that lie outside the Taiga Shield, so research both within and beyond the ecozone+ is vital for detecting and explaining trends.
Specific strengths and gaps in information that emerged in the preparation of this report
Monitoring and research strengths include studies that aid in understanding the ecology of Canada's remaining large migratory caribou populations, for example for the George River herd in the eastern Taiga Shield and the Bathurst herd in the western Taiga Shield (see the Northern caribou population trends in Canada thematic technical reportFootnote 12). Research that links impacts from climate change, development activity, and increased human presence in the Taiga Shield, along with monitoring of herd abundance, distribution, and caribou health and body condition, are needed on an ongoing basis.
Existing information on the Taiga Shield ecozone+ is scattered over several jurisdictions and academic research groups – there is little ongoing ecological monitoring. Much of the information that is available is in the "grey literature" rather than in the published scientific literature. The disadvantage of this is that interpretations of results are not always adequately scrutinized and records are not always readily accessible, especially in the long term.
Coverage of the ecozone+ by climate stations is poor – the existing coverage does not allow for generalization to regional trends.
Knowledge about forest ecosystem processes is crucial for understanding taiga biodiversity. Critical gaps, especially for the western part of the ecozone+, are forest processes in relation to climate change and fire ecology, including the ecological importance, status and trends of invertebrates, fungi, and other poorly studied species assemblages.
Information is lacking on causes of the decline of eelgrass and continued trend monitoring is needed. (The issue of the condition of eelgrass beds in James Bay was referred to the Standing Committee on Fisheries and Oceans which, in 2008, presented a report to the House of Commons recommending in-depth research into the effects of environmental change on the eelgrass beds, as well as larger scale monitoring in James and Hudson bays.Footnote 43)
Information about population cycles, natural disturbances and human impacts comes from time lines too short to provide good insights. Gathering historical information from early records, landscape and proxy studies would provide a broader perspective on trends.
Understanding of ecological thresholds and causes of rapid change in the boreal forest is poor. Thresholds related to weather conditions – for example, for species range extensions, wildlife disease and forest insect outbreaks – are particularly important to understand in order to foresee and detect early signs of major ecological impacts from climate change in the Taiga Shield ecozone+.
Rapid change and thresholds
National key finding
Growing understanding of rapid and unexpected changes, interactions, and thresholds, especially in relation to climate change, points to a need for policy that responds and adapts quickly to signals of environmental change in order to avert major and irreversible biodiversity losses.
There are two clear instances of abrupt change for this ecozone+:
- the precipitous decline in at least one population of migratory tundra caribou in the past few years (see Migratory tundra caribou on page 47 and Changes in availability of traditional/country foods on page 42).
- the rapid breakdown of permafrost in peatlands of the eastern Taiga Shield (see Permafrost trends on page 17).
Compounded disturbances that occur could push communities past their ability to recover.Footnote 168 For example, boreal forests may be resilient to climate trends until the interaction of human-induced changes such as the introduction of non-native species, diseases, or changes in fire regimes combine with atmospheric deposition of nitrogen or heavy metals.Footnote 169
In addition, species diversity is low in the Taiga Shield. A relatively few species drive ecosystem functioning. The low species diversity, combined with cyclic abundance of some species, suggest that changes to ecosystem structure could be large-scale and relatively unpredictable.
- Footnote 12
Gunn, A., Russell, D. and Eamer, J. 2011. Northern caribou population trends in Canada. Canadian Biodiversity: Ecosystem Status and Trends 2010, Technical Thematic Report No. 10. Canadian Councils of Resource Ministers. Ottawa, ON. iv + 71 p.
- Footnote 43
Standing Committee on Fisheries and Oceans. 2008. Fifth report of the Standing Committee on Fisheries and Oceans to the House of Commons. Government of Canada. Ottawa, ON. 2 p.
- Footnote 167
Scheffer, M. and Carpenter, S.R. 2003. Catastrophic regime shifts in ecosystems: linking theory to observation. Trends in Ecology & Evolution 18:648-656.
- Footnote 168
Paine, R.T., Tegner, M.J. and Johnson, E.A. 1998. Compounded perturbations yield ecological surprises. Ecosystems 1:535-545.
- Footnote 169
Chapin, F.S., Callaghan, Y., Bergeron, M., Johnstone, J.F., Juday, G. and Zimov, S.A. 2004. Global change and the boreal forest: thresholds, shifting states or gradual change? Ambio 33:361-365.
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