Vegetation

Vegetation provides habitat to wildlife and ecosystem services such as food and fuel and many other products to humans. Vegetation defines landscapes in people’s minds, and is an essential component of any biome or environment. NWT has large sections of two of the earth’s biomes: the taiga and the tundra.

Indicators on vegetation and factors that affect vegetation, such as fire and insect disturbances, can help track changes in the health and integrity of taiga and tundra ecosystems. Indicators on vegetation responses to stresses like pollution, to some land uses, and to disturbances can provide early warning of changes in northern ecosystems that are harder to measure. These vegetation indicators give information on condition, changes and trends in vegetation communities, including taiga and tundra ecosystems.

Additional indicators on changes in vegetation communities on the tundra are being developed.

14.1 Land Cover Types by Ecozone

This indicator shows the distribution of 17 primary land cover types over the five ecozones of the NWT

The dataset used is from the Earth Observation for Sustainable Development of Forests (EOSD)(3) , a joint program of the Canadian Forest Service (CFS) and the Canadian Space Agency (CSA). It was developed as part of a forest monitoring system for Canada. EOSD is designed to provide, over the long term, products for forest inventory, forest carbon accounting, monitoring of sustainable development, and landscape management using space-based earth observation data. Inputs from EOSD are an important data source in the National Forest Carbon Accounting Framework(1) and Canada’s new plot-based National Forest Inventory(6) . Numbers reported for the Northern Arctic and Southern Arctic Ecozones are from the Northern Canada land cover product.

NWT Focus

Concern over the state of the earth’s environment has resulted in an increased need for accurate land cover information. Land cover mapping is necessary to provide input to scientific models to ensure forest management is sustainable and to monitor environmental change. In addition, land cover mapping is required to meet commitments made to international agreements on climate change (e.g., the NFCMARS) and biodiversity (e.g., CBD).

This information shows how land cover and vegetation communities are distributed across the NWT landscape. Vegetation information is important baseline information that may be used to examine forest health and changes to vegetation patterns at the landscape level.

Current view: status and trend

The EOSD land cover map of the forested area of Canada is based on Landsat data and represents conditions for year 2000. At the present time there is no information to determine trend.

About 24 % of NWT for which there is data on cover, is wetlands, lakes and rivers, 12% is sparsely vegetated lands (barren lands), 30% is grasslands and shrub lands, and 34% is forests. Only 27% of the Northern Arctic ecozone is classified, so updates in the data will change these estimates slightly in the future.

NWT land cover by ecozone - baseline Year 2000

Percent cover of major groupings of land cover by ecozone – baseline year 2000

Looking forward

Over the longer term, EOSD will aim to produce land cover products to capture the conditions present for past years (e.g., for 1990 and for future reporting years occurring after 2000. Better coverage and products continue to be developed for the North.

In the future we expect to see increased impact to forest and vegetation communities due to human disturbance. In the NWT, resource-based economies are growing, including oil and gas exploration and extraction, and mining. Most development activities will be in the forested ecozones, particularly in the Taiga Plains along the Mackenzie River and near NWT communities.

Climate change may cause significant changes to the distribution of land cover types if there are drastic changes in precipitation or incidence of wildfires. Many tree and vegetation species are at their northern range limit, so impacts may be more obvious than other places in Canada. For example, change in tundra vegetation is noted as more shrubs (willows) are observed near the tree line(7) , and satellite measurements(17) are showing that the tundra is becoming greener,with more growth in vascular vegetation but less growth in lichen-dominated areas.

Looking around

Most other jurisdictions in Canada have detailed air-photo based vegetation inventories. Some jurisdictions in Canada get new complete air-photo coverage of their province on a ten-year cycle. NWT has similar detailed information only for very localized areas, and it is not updated on a regular basis. The EOSD classified Landsat coverage of Canada and the Northern Canada land cover classification are a first approximation of vegetation types that covers all of NWT. The information will be useful for a variety of reporting purposes, particularly on a national basis.

Many programs use this indicator to track changes to vegetation and inform on sustainability and carbon storage. Information from the NWT is added to information from other regions in Canada and the world, and reported back for these organizations:

United Nations Food and Agriculture Organization - Forest Resource
Assessment (UNFAO – FRA)
Reporting every 5 year
http://www.fao.org/

Canadian Council of Forest Ministers, Criteria and Indicators of Sustainability (CCFM C&I)
Reporting every 5 years
http://foretscanada.rncan.gc.ca/articletopic/69

United Nations Framework Convention on Climate Change, National Forest Carbon Monitoring, Accounting and Reporting System (NFCMARS)
Reporting every year
http://carbon.cfs.nrcan.gc.ca/index_e.html

Canadian Forest Service’s State of the Forest Report
Reporting every year.
http://foretscanada.rncan.gc.ca/rpt

Find out more

• Earth Observation for Sustainable Development land cover product http://www.pfc.forestry.ca/eosd/cover/mapping_e.html
• Northern Land Cover Classification can be obtained from Canada Centre for Remote Sensing.

Other focal points

• For more indicators related to landscape, see the Focal Point Landscape Changes.

Technical Notes

• The land cover classification legend can be found on the EOSD webpage(5). http://www.pfc.forestry.ca/EOSD/cover/EOSD_legend_report-v2.pdf
• Northern Land Cover Classification can be obtained from Canada Centre for Remote Sensing.

14.2.Position of Treeline

This indicator measures the position of treeline in the NWT. There have been many attempts to define treeline in northern Canada. The recently adopted treeline definition used by the NWT is of a forest that contains at least 25% crown closure and is at least 5 meters tall at maturity.

The new standard treeline is defined as the extent of forestlands pertinent to reporting under the Kyoto Protocol. The details of the definition were agreed to within the framework of the Marrakech Accord and are reported by the Canadian government under its obligations as a signatory to the Kyoto Protocol. For the first time, the treeline has been surveyed in the NWT using this standard.

NWT Focus

The NWT is home to the northern range of boreal forest in Canada, and contains a large extent of treeline. The current position of the treeline has management implications for reporting on forest cover and carbon accounting in Canada.

Current view: status and trend

The position of the treeline has changed since the end the last glaciation period. The cold waters of Hudson Bay have an important impact on the current location of the treeline on the barrens. Cool temperatures have slowed the advance of tree species near the Hudson Bay, and warm waters from the Mackenzie River havecreated conditions for tree growth all the way to Inuvik and the Coppermine River.

Black and white spruce can be found up to the treeline, with white spruce prevailing at higher latitudes and on calcareous soils. Jack pine is not present at the treeline. Aspen distribution is more complex – aspen can occur right up to the Mackenzie Delta and on southerly slopes in the High Subarctic near the tree line.

Source: unpublished paper: Downing, February 5, 2008; Taiga Plains ELC Report; Taiga Shield ELC Report; UNFCCCC Marrakech COP 7; Timoney et.al. 1992)

Looking forward

Factors that could affect treeline position in the future are changing temperature and precipitation patterns. Different site conditions can favour more rapid growth or cause tree mortality in some forest communities at the treeline Trees migrate very slowly and dispersal of seeds is often measured in tens of meters. As well, vegetative expansion moves at a rate of meters per year. The effects of climate change on the treeline in the NWT are not yet well understood.

At this point, there is not enough information at multiple sites to be able to forecast how changing temperature and precipitation will affect the location of NWT’s entire treeline.

Looking around

Scientists are predictingthat the treeline will advance north with rising temperatures. The treeline in Alaska(14) and in Yukon(9) is changing, but in complex ways, as trees are showing more growth in some areas, and dying in others.

This baseline indicator is useful for any researchers looking to fix a foundation or baseline on the landscape to watch for the effects of a changing climateon the treeline. As they grow, trees take huge amountsof carbon out of the atmosphere, contributing to a reduction in the effects of greenhouse gas emissions. This indicator tracks changes in the extent of the taiga, an important carbon-regulating ecosystem(1).

Find out more

• Find more on Forest Carbon Accounting and the Kyoto treeline definition at http://carbon.cfs.nrcan.gc.ca/index_e.html.

Other focal points

• For more information on landscapes, go to the Landscape Changes focal point.

Technical Notes

• The High Boreal ecoregionlines can be used as a surrogate for the northerly extent of jack pine in the Taiga Plains. The Low Subarctic ecoregion lines can be used as a surrogate for the northerly extent of jack pine in the Taiga Shield. The High Boreal ecoregions are generally the northward extent of aspen stands on average sites. See the GNWT Ecological Classification reports for more information (www.nwtwildlife.ca).

14.3 Annual area burned and number of fires

This indicator measures the annual number of fires and area impacted by wildland fires greater than 200ha.

Information for this indicator is obtained from the Northwest Territories Department of Environment and Natural Resources, Forest Management Division, the agency responsible for providing forest fire management services on forested areas in the NWT

NWT Focus

Forest fire is a natural phenomenon. Fire is the major stand-renewing disturbance in the boreal and taiga forests around the world. The forests of western North America, under the right conditions, such as hot weather and low forest fuel moisture, will support high-intensity wildlandfires. These fires often occur naturally and have the potential to spread quickly, covering large areas. Tracking fires in the NWT is essential to maintaining our ecosystems and fulfillingour duty to protect human life. An accurate understanding of the number of wildfires and area affected is necessary to effectively monitor the state of the environment and manage forest resources.

Current view: status and trend

Although dramatic fluctuations in area burned and the number of fires occur annually, a linear regression shows a weak trend towards a reduction in both the area burnt and the number of fires greater than 200ha between 1988 and 2008. On average, every year, about 204 fires occurred in the Northwest Territories(21). Years with the highest number of fires were 1989, 1994, 1998, and 2004 (see graph). The average area burned every year is 337,000 hectares (ha)(21).

Area burned and number of fires greater than 200ha in the NWT (Includes Nunavut up to 1998).

Looking forward

As the cost and impacts of managing wildland fires continues to increase, coupled with the potential implications of climate change, ensuring accurate baseline information is necessary to monitor environmental change and establish effective preparedness levels. It is logical to assume that the frequency and intensity of fires will change as climate changes. A longer fire season, associated with changes in precipitation and temperature, coupled with additional stresses to forest and vegetation such as drought, flooding, insects and disease, reinforce the importance of monitoring this indicator.

Looking around

On average, more fires occur in British Columbia (1,800), Alberta (1,127) and Ontario (1,390) than in other jurisdictions in Canada(21). As opposed the Northwest Territories, where most fires are caused by lightening strikes, many fires in other Canadian jurisdictions are started by humans. The jurisdiction with the highest area burned every year, on average, is Saskatchewan, followed by the Northwest Territories(21).

Details on every fire greater than 200ha in the Northwest Territories is forwarded to the following organization, to provide Canada-wide information on fire as an indicator of the state of the environment in Canada:

Canadian Interagency Forest Fire Centre
Reporting every year
http://ciffc.ca/

Find out more

• Please visit FMD’s website for more information; http://forestmanagement.enr.gov.nt.ca/
• For more information on national fire averages please visit: http://ciffc.ca/. The Canadian Interagency Forest Fire Centre (CIFFC) provides operational wildlandfire-control services, as well as management and information services to Canadian Fire Management. FireWire is the online fire data service of CIFFC. Viewers can access a stream of constantly-updated Situation Reports every day during the forest fire season onlineat: http://www.ciffc.ca/index.php?option=com_content&task=view&id=25&Itemid=212

14.4 Trends in alien plant species

This indicator trackslong-term changes in plant communities due to the introduction and spread of alien plant species in NWT’s ecosystems.

This indicator is also used to track the status of vascular plant species in the NWT General Status Ranking Program. All species tracked by this indicator are alien species, which are defined as species that have been introduced into North America from Europe or Asia as a result of human activities.

The indicator also provides information on the level of invasiveness for each alien species. Invasive species are harmful alien plant species whose introduction or spread threatens the environment, the economy, or society. Plants can be invasive in one area or ecosystem and less in another. Synonymous with weed.

Predicted levels of invasiveness are preliminary and apply to the entire NWT, based on assessments in Canada(2). These may change in future as more studies and information becomes available. The following categories are used to describe the level of invasiveness.

This indicator uses information collated from NWT residents and visiting experts, as well as information summarized from the NWT General Status Ranking Program and projects undertaken for the Risk Analysis of Invasive Alien Species in the NWT funded in part by the AIS Partnership Program.

NWT Focus

Changes in the number of alien species in the NWT are monitored as their presence and abundance may affect the status of wild species native to NWT. Plant species are introduced to NWT as food crops, habitat remediation tools, landscaping varieties, or simply unintentionally. The majority of introduced (alien) plant species cause no damage to natural ecosystem because they need constant human assistance to survive and do not spread. NWT’s climate prevents many species from establishing themselves in NWT’s ecosystems. Some introduced plant species have, however, succeeded in spreading in some habitats, mostly those already disturbed by human activities. Some introduced plant species can spread and cause harm to natural habitats, out-competing native plant species.

Current view: status and trend

So far, there are no known alien plant species with a high level of invasiveness in the NWT.

In 2005, 94 alien plant species were known to occur in the NWT. One survey(16) along NWT roads in 2006 increased this number to 106. These are mostly found in or near communities, near roads, and along disturbed areas such as cut-lines, pipelines, and mine sites.

Of these 106 species, few have demonstrated that they can invade natural habitats(2) (see table below). White and yellow sweet clovers are increasingly common in the NWT, from the Alberta border up to Norman Wells and Inuvik. These species are widespread in communities and along roads(16). There are reports that they have been found outside man-made habitats in the NWT, but these need confirmation. These species are now known to invade river margins and sandy/muddy natural habitats in Alaska and Yukon(8).

The predicted invasiness of alien plant species is based on studies from across Canada(2,10) and is applied to the NWT in a preliminary fashion. More studies on the distribution and biology of alien plants in the NWT are being conducted(16).

Species name	Family	Introduction Notes	Habitat or Occurrence Notes	Predicted Invasiveness
White Sweet Clover (Melilotus alba)	Pea (Fabaceae)	Introduced from Eurasia	Roads, increasingly common in upper Mackenzie R., some sites along pipeline to Norman Wells. Taiga Shield and Taiga Plains.	Moderate
Yellow Sweet Clover  (Melilotus officinalis)	Pea (Fabaceae)	Introduced from Eurasia	Recent in waste places, roadsides in southernmost Mackenzie River, along pipeline to Norman Wells. Taiga Shield and Taiga Plains (south)..	Moderate
Alfalfa  (Medicago sativa)	Pea (Fabaceae)	Introduced from Eurasia(?)	Widespread along NWT highways, and at least 1 site along pipeline to Norman Wells. Taiga Plains (south).	Low/ Potential
Siberian Peashrub  (Caragana arborescens)	Pea (Fabaceae)	Introduced	Fort Smith, Fort Liard, Liard River at Petitot River, probably other places, escaped from gardens. Taiga Plains (south)	Low/ Potential
Awnless Brome  (Bromus inermis)	Grass (Poaceae)	Introduced from Eurasia	Cultivated and found on roads and waste places. Taiga Shield and Taiga Plains.	Moderate/ Low
Reed Canary Grass  (Phalaris arundinacea)	Grass (Poaceae)	Presence of exotic genotypes among NWT sites is uncertain	Sites in southern NWT and 14 sites along the pipeline to Norman Wells, part of seed mix applied in 1984. Taiga Shield and Taiga Plains (south).	Moderate/ Low
Crested Wheat Grass (Agropyron cristatum spp pectinatum)	Grass (Poaceae)	Introduced from Russia (or Europe)	Introduction near waste sites and townsites in south Mackenzie River area. Taiga Shield and Taiga Plains.	Low/Potential
Flat-stem Blue Grass  (Poa compressa)	Grass (Poaceae)	Introduced from Eurasia	Fort Simpson, Liard Trail (Hwy 7), west of Yellowknife, maybe elsewhere near southern Mackenzie River. Taiga Shield and Taiga Plains (south).	Minor /Potential
Kentucky Blue Grass (Poa pratensis)	Grass (Poaceae)	Forms in the NWT are probably not native and introduced as lawn grass	Near settlements, roads and one site on the pipeline to Norman Wells. Taiga Shield and Taiga Plains.	Minor /Potential
Hoary False-alyssum (Berteoa incana)	Mustard (Brassicaceae)	Introduced from Eurasia	First site discovered in 2006 along Hwy. 3. Taiga Shield.	Low
Creeping Thistle  (Cirsium arvense)	Thistle (Asteraceae)	Introduced from Eurasia	Fort Simpson, Hay River, Fort Providence near highway and Yellowknife. Taiga Shield and Taiga Plains (south).	Moderate/ Low
Common Tansy (Tanacetum vulgare)	Thistle (Asteraceae)	Introduced from Eurasia	Along roads in southern NWT, as well as in Inuvik. Taiga Shield and Taiga Plains.	Potential

Some plant species have both native and alien subspecies and varieties. These species may be used in seed mixes, especially if these varieties have been selected for “aggressiveness” or “pioneer capacity” that is their capacity to quickly grow, invade, and cover an area to offer some erosion control. However, as only the species name, not the full subspecies or variety name, is usually reported in re-generation programs, it becomes difficult to determine whether alien subspecies/varieties or native ones are being used. The invasiveness potential of these subspecies is mostly unknown for the NWT. Some of these subspecies are found today along seismic lines, pipelines or re-vegetated mines and other sites.

Looking forward

The North lags behind other North American jurisdictions in preventing introduction, controlling and eradicating invasive alien plants that could threaten native ecosystems, habitats, or species. We may have been complacent in our view of the threats of invasive alien species to the North’s ecosystems, assuming that our northern climate will prevent most species from establishing themselves here. With increasing development in the NWT, and an increase in habitat changes expected in the Taiga Plains, communities are preparing to increase their awareness of the risks related to alien plants and to help reduce that risk. NWT people have noticed an increase in plant species that are “out-of place” – or alien and “taking over some habitats” – or becoming invasive.

Every year, botanists collect plants, identify them and store them in botanical collections in museums in Canada, the U.S., England, and elsewhere. A project on plant data repatriation was initiated in 2007 to assemble a database of all plant locations and information on specimens collected in the NWT since the 1800s. Using this database, the NWT will be able to map all known locations of alien plants, analyse distribution patterns and identify future problems related to introduction of potentially invasive alien plant species.

With increases in development and climate change, the NWT can expect more alien plant species to arrive and some to move to natural habitats and become invasive. A risk analysis and management options plan is being developed to help detect these plants early, and to eradicate or control them as necessary.

There is increasing demand in the NWT for seed mixes containing native plant species for work in revegetation plans and mitigation activities.

Looking around

In areas where there is greater native plant diversity (number of plant species), more species of alien plant species are usually also found.(19) For example, the NWT has about 1036 native vascular plants; this is more than Nunavut (618) and less than the Yukon (1081). The number of alien plant species found in the NWT (106) also falls between the numbers of alien plant species detected in Nunavut (20) and Yukon (118). This relationship is linear for all western and northern jurisdictions in Canada. The NWT has about the number of alien plant species expected for a northern jurisdiction considering the number of native species present here. Note that if a province/territory is rich in native plant species, it tends to be “better” for exotics. Conversely, if it is poor in native plants, it is worse for exotics(19) . In BC, which is rich in plant species, 23% of vascular plants are alien species, whereas in the NWT, which is relatively poor in plant diversity, only 9% of vascular plants are alien species.

A different ratio of alien to native plant species is observed in eastern Canada, where three times more species of alien plants are observed compared to what we would expect in western and northern Canada. Possible reasons for this include the longer history of habitat use and human settlements in eastern Canada resulting in more disturbed habitats that are presumably more favourable to alien plants(11), and higher rates and more points of entry for plant introductions for food and gardens.

Find out more

• Find out more about invasive alien species in Canada at www.ec.gc.ca/eee-ias/, and around the world with the IUCN Invasive Species Specialist Group at www.issg.org/IUCNISGuidelines.html#GISP. A complete list of all alien plant species known to occur in the NWT can be found in Oldham (2006), and in the NWT Species Infobase (www.nwtwildlife.com).
• Additional information on the biology and global distribution of all alien plant species found in the NWT can be accessed on the Global Invasive Species Database, managed by the Invasive Species Specialist Group (ISSG) of the IUCN Species Survival Commission http://www.issg.org/database/welcome/

Other focal points

• Information on alien insects and on alien mammals, birds and fish species is in the WILDLIFE focal point

Technical Notes

• The definition invasiveness is based on the definition contained in the Convention on Biological Diversity Decision VI/23 and the and the Invasive Alien Species Strategy for Canada(10).
• All photos are from Mike Oldham © ENR, GNWT.

14.5 Status of species harmful to forests in the NWT

This indicator tracks species of insects and spiders present in the NWT that are considered alien, invasive, or pests,and that can be harmful to our plant communities including our forests.

This indicator uses information collected for the NWT General Status Ranking Program (GSRP) and from a project called: Risk Analysis and Management of Alien Plant and Insects in the Northwest Territories, funded by Environment Canada, Indian and Northern Affairs Canada, GNWT Environment and Natural Resources, Parks Canada, and Agriculture Canada. Additional information on forest pest insects was obtained from forest experts in ENR Forest Management, and NRCAN’s webpage: Forest Invasive Alien Species in Canada(15).

The indicator tracks species using three definition codes.

NWT Focus

Changes in the number of alien, invasive, or pest species of insects and spiders in the NWT provide an indicatorof ecosystem change, including habitat and climate change. Changes in the number of alien insects and spiders are also monitored as their presence and abundance may affect the status of wild species native to the NWT.

Arthropods (insects, spiders) form the most diverse part of NWT’s biodiversity; it is estimated that thousands of species can be found in the NWT’s ecosystems. Insects and spiders have adapted to harsh climates, and the great majority of NWT’s species are present year-round, i.e., they are not migratory. The number of alien and pest species present further south is much greater. Changes in the northern environment may favour advance of these species intoour ecosystems.

Current view: status and trend

So far, we know of 11 alien species of insects and no spiders that are present in the NWT. Most of these species have been noted in the NWT for more than 50 years, but the extent of their distribution is unknown. Two of these alien species (the Larch Sawfly and the Amber-marked Birch Leafminer) are subject to monitoring programs.

Common Name	Scientific species name	Definition Code	Comments
Lepidoptera			Butterflies and Moths
Cabbage White (Cabbage Worm)	Pieris rapae	Alien	Introduced to NA in Quebec City circa 1860 from Eurasia; quickly spread to gardens across NA, but not recorded in NWT until 2001 (Yellowknife, Fort Simpson, Yohin Lake in Nahanni National Park Reserve); to be looked for elsewhere(12). Hosts: mustard family(15).
Rusty Tussock Moth	Orgyia antiqua	Alien; Invasive; Forest Pest	Present in the NWT, extent unknown. Considered invasive and a pest in Canada but does little damage in the NWT. Hosts: spruces and pines(15).
Birch-aspen Leafroller Moth	Epinotia solandriana	Alien; Minor invasive	Present in the NWT as early as the 1960s(15). Considered a minor invasive. Hosts: trembling aspens, alders and yellow birch(15).
Hemiptera - Coccidae			True Bugs - Wax Scales
Small Sprucebud Scale	Physokermes hemicryphus (P. piceae)	Alien; Invasive	Present in the NWT(13), but extent is unknown. Considered invasive in Canada. Host: spruces..
Hemiptera - Adelgidae			True Bugs - Adelgids
Larch Woolly Adelgid	Adelges laricis	Alien; Invasive	Present in the NWT, but extent is unknown. Requires both spruce and larch (tamarack) for development. Origin: Europe. Considered invasive in Canada..
Hymenoptera - Tenthredinidae			Sawflies
Larch Sawfly	Pristiphora erichsonil	Alien; Invasive	First observed in Canada in 1882(22); from Europe. Quickly spread to larch and tamarack forests across the US and Canada. Reached the North in the 1960s. Now present in various densities across all forested ecozones in the NWT. GNWT Forest Management and Canadian Forest Service monitor outbreaks annually.
Striped Alder Sawfly	Hemichroa crocea	Alien; Invasive	Present in the NWT, extent is unknown. Larvae feed on alder and birch leaves. Origin: Eurasia. Considered invasive in Canada.
Birch Leaf Edgeminer	Scolioneura betuleti (Heterarthrus nemoratus)	Alien; Pest	First noted in NWT in 2003 in Hay River town, Hay River Beach, Yellowknife(18). First observed in Canada in 1905(22). Introduced from Europe. Hosts: alders and birches. Not considered invasive, but a pest.
Amber-marked Birch Leafminer	Profenusa thomsoni	Alien; Invasive; Pest	First noted in the NWT in 1994; Abundant in Yellowknife, extending into the surrounding wild birch stands, mostly along the Ingraham Trail and other roads. Present in Hay River, and other areas in the South Slave region(18). Introduced in 1948 from Europe, now present across Canada(15). Turns trees brown in mid-summer and is of public concern for aesthetic reasons, but in the future may also affect large tracks of birches outside built-up areas as in Alaska(20). Considered invasive and a pest. Hosts: trembling aspens, alders and yellow birch(15).
European alder leafminer	Fenusa dohrnii	Alien	Observed in wild stands near Hay River and Behchoko, Fort Resolution, Fort Simpson, and Fort Liard in 2003. Attacked speckled alders but not green alder. Entire extent in the NWT is unknown but suspected that it is expanding largely without assistance from humans. First observed in NA in 1890s(18).
Birch Leafminer	Fenusa pumila (Fenusa pusilla)	Alien; Invasive; Pest	First noted in the NWT in 2003 in Hay River(18). From Europe. Introduced to NA in 1923, was observed in Canada in 1929, now present across Canada. Considered invasive and a pest. Hosts: birches.
Coleoptera - Chrysomelidae			Beetles – Leaf Beetles
Poplar Blackmine Beetle	Zeugophora scutellaris	Alien; Invasive	Present in the NWT, extent is unknown. Origin is Eurasia. Hosts: poplars and aspen. Considered invasive in Canada.

Source: Information from the NWT General Status Ranking Program and as referenced.
Butterflies photos courtesy of The Butterflies of Canada by Ross A. Layberry, Peter W. Hall, and J. Donald Lafontaine. University of Toronto Press; 1998. (web version).
Larch sawfly larva photo courtesy of University of Georgia, obtained from /www.fs.fed.us/r10/spf/fhp/leaflets/Larsaw.htm Rusty Tussock Moth photo: adult: USDA Forest Service Archives, USDA Forest Service, www.forestryimages.org,
Caterpillar: Connecticut Agricultural Experiment Station Archives, Connecticut Agricultural Experiment Station, www.forestryimages.org
Birch-aspen Leafroller Moth photo courtesy of Edward H. Holsten, USDA Forest Service, Bugwood.org, obtained from www.forestryinmages.org.
AMBLM and Birch Leafminer: Thérèse Arcand, Natural Resources Canada, Canadian Forest Service, Laurentian Forestry Centre Small Sprucebud Scale: Edward H. Holsten, USDA Forest Service, United States, Bugwood.org
Larch Woolly Adelgid: Louis-Michel Nageleisen, Département de la Santé des Forêts, Bugwood.org
Striped Alder Sawfly: USDA Forest Service - Alaska Archive, USDA Forest Service, Bugwood.org
Poplar Blackmine Beetle : Whitney Cranshaw, Colorado State University, Bugwood.org
European alder leafminer: Whitney Cranshaw, Colorado State University, Bugwood.org

In addition to alien species, some native insects such as the Spruce budworm (Choristoneura fumiferana), tent caterpillars (Malacosoma spp.), and bark beetles (Scolytidae) can significantly damage NWT forests. Spruce budworm infestation is monitored in the NWT. In the late 1990’s and early 2000 there was an unprecedented increase in spruce budworm. However, by 2002 the population started to decline and then in 2005, the population had almost completely collapsed in all but the extreme north.

Looking forward

NWT residents can help determine the current distribution of alien species in the NWT by reporting their presence to ENR offices. Official species lists have been compiled for the NWT General Status Ranking Program since 2000(23). Species lists include butterflies, tiger beetles, dragonflies and damselflies. Official species lists for NWT spiders, some groups of beetles, moths, deer flies, horse flies, bees, black flies and mosquitoes are being developed and will be available for tracking by this indicator in 2010. Updates on new species of insects are possible only through the contributionsof visiting entomologists, tourists, and NWT residents interested in NWT biodiversity.

Looking around

The Mountain Pine Beetle (Dendroctonus ponderosae), one of the more intensely monitored forest pest insects in western North America(4), is creating unprecedented damage to lodgepole pine forests in British Columbia and Alberta. The advances of that species are tracked by ENR forest experts, and they have not been observed in the NWT yet.

Find out more

• To find on insects in the NWT and elsewhere in Canada go to Biological Survey of Canada (http://www.biology.ualberta.ca/bsc/bschome.htm ) For more information on the NWT General Status Ranking Program go to www.nwtwildlife.com.
• For more information on the Mountain Pine Beetle, go to British Columbia’s Mountain Pine Beetle Action Plan, at http://www.for.gov.bc.ca/hfp/mountain%5Fpine%5Fbeetle/.

Other focal points

• See VEGETATION – FOREST for other indicators on insects, especially forest pests in the NWT.

References

1. 2008, National Forest Carbon Accounting Framework, National Forest Carbon Accounting Framework, http://carbon.cfs.nrcan.gc.ca/
2. Canadian Botanical Conservation Network, 1997, Invasive Herbaceous Species List, http://www.rbg.ca/cbcn/en/projects/invasives/i_list.html, Royal Botanical Gardens http://www.rbg.ca/cbcn/en/projects/invasives/i_list.html
3. Canadian Forest Service, Natural Resources Canada, 2008, Earth Observation for Sustainable Development of Forests, CFS, http://www.pfc.forestry.ca/EOSD/index_e.html
4. Canadian Forest Service, Natural Resources Canada, 2008, Forest.forward Moving beyond the pine beetle, Natural Resources Canada, http://mpb.cfs.nrcan.gc.ca/biology/index_e.html
5. Canadian Forest Service, Natural Resources Canada, 2008, Land Cover Mapping and Legend, CFS, http://www.pfc.forestry.ca/eosd/cover/legend_e.html
6. Canadian Forest Service, Natural Resources Canada, 2008, National Forest Inventory, CFS, http://nfi.cfs.nrcan.gc.ca/
7. Communities of Aklavik, Inuvik Holman Island Paulatuk and Tuktoyaktuk Nickels S. Buell M. Furgal C. Moquin H., 2005, Unikkaaqatigiit – Putting the Human Face on Climate Change: Perspectives from the Inuvialuit Settlement Region., Ottawa:Joint publication of Inuit Tapiriit Kanatami, Nasivvik Centre for Inuit Health and Changing Environments at Université Laval and the Ajunnginiq Centre at the National Aboriginal Health Organization.http://www.itk.ca/sites/default/files/Inuvialuit.pdf
8. Conn, J., Beattie, K., Shephard, M., Carlson, M., Lapina, I., Hebert, M., Gronquist, R., Densmore, R., and Rasy, M., 1-5-2008, Alaska Melilotus Invasions: Distribution, Origin, and Susceptibility of Plant Communities, Arctic, Antarctic, and Alpine Research, 40,(2):298- 308
9. D'Arrigo, R. D, R.K.Kaufmann, N.Davi, G.C.Jacoby, C.Laskowski, R.B.Myneni, and P.Cherubini, 2004, Thresholds for warming-induced growth decline at elevational tree line in the Yukon Territory, Canada., Global Biogeochem.Cycles, 18,(GB3021-
10. Federal, provincial and territorial Ministers of forests fisheries and aquaculture and wildlife, 2004, Invasive Alien Species Strategy for Canada, Government of Canada.http://www.ec.gc.ca/eee-ias/default.asp?lang=En&n=98DB3ACF-1
11. Janet C Lake. and Leishman, M. R., 2004, Invasion success of exotic plants in natural ecosystems: the role of disturbance, plant attributes and freedom from herbivores, Biological Conservation, 117,(2):215- 226
12. Layberry Ross, 30-9-2005, Butterflies,
13. Malcolm M.Furniss, 2004, Observations on an introduced bud scale, Physokermes hemicryphus (Homoptera: Coccidae), infesting Norway spruce in Idaho. Can.J.For.Res., 34,(1348- 1352
14. Martin Wilmking, Glenn P.Juday, Valerie A.Barber, and Harold S.J.Zald, 2004, Recent climate warming forces contrasting growth responses of white spruce at treeline in Alaska through temperature thresholds, Global Change Biology, 10,(10):1724- 1736
15. Natural Resources Canada, 2008, Forest Invasive Alien Species of Canada, Natural Resources Canada,
16. Oldham, M., 2006, 2006 Survey of Exotic Plants along Northwest Territories Highways, Report to the GNWT,
17. Olthof, I., Pouliot, D., Latifovic, R, and Chen, W., 2008, Recent (1986-2006) vegetation-specific NDVI trends in Northern Canada from satellite data, Arctic, 61,(4):381- 394
18. SC Digweed and DW Langor, 2005, Distributions of leafmining sawflies (Hymenoptera: Tenthredinidae) on birch and alder in northwestern Canada, Canadian Entomologist, 136,(727- 731
19. Scott C.Stark, Daniel E.Bunker, and Walter P.Carson, 2006, A null model of exotic plant diversity tested with exotic and native species-area relationships, Ecology Letters, 9,(136- 141 http://www.columbia.edu/~deb37/publications/StarkBunkerCarson2006.pdf
20. Snyder Cynthia, MacQuarrie, Chris J. K., Zogas, Ken, Fruse, James. J., and Hard John, 2007, Invasive species in the last frontier: distribution and phenology of birch leaf mining sawflies in Alaska., Journal of Forestry, April/May 2007,(113- 119
21. Tom Johnson, 2007, CIFFC Canada Report 2007, Canadian Interagency Forest Fire Centre. http://www.ciffc.ca/images/stories/pdf/2007_Canada_Report.pdf
22. U.S.Department of Agriculture (USDA), 2001, The Larch Sawfly, United States Department of Agriculture, Forest Service, Leaflet R10-TP- 101, http://www.fs.fed.us/r10/spf/fhp/leaflets/Larsaw.htm
23. Working Group on General Status of NWT Species, 2005, NWT Species Infobase 2005-2010, Version 2007.2,