baltimore oriole ring-necked pheasant state-colored junco

Baltimore Oriole

Ring-Necked Pheasant

State-colored Junco

Great-tailed Grackle

Magnolia Warbler

Blackburnian Warbler

Black-throated Green Warbler

In 2001, more than 1.9 million

Minnesota spent $532 million

watching wildlife.

– 2001 National Survey of Fishing Hunting, and Wildlife-Associated Recreation

Eastern Spruce Budworm

• Native phytophagous insect occurring along the North America boreal-forest zone

• Preferred plant species are balsamfir and spruce species

• Usually present in low numbers, occasionally undergoes large outbreaks

• Annually defoliates 5.7 million hectares in eastern United States

• Number one forest pest in Canada. Timber losses are estimated at 51 million m3 a year. This is a 1.5 times that of wildfire and a significant proportion of the annual timber harvest volume.

Outbreaks

• Population sizes in outbreaks can reach 22 million larvae per hectare and 1.2 million pupae per hectare. High population densities can last from 5-15 years.

• High density populations cause >80% loss of new foliage on fir for 4-6 years. This seriously retards the growth or kills the tree. Can kill almost all trees n dense mature stands of fir.

• Spruce budworms strongly control therate and direction of succession. Balsam fir has already been eliminated from some western stands.

• They contribute significantly to biomass decomposition, carbon cycling, nutrient cycling and energy flow in forest ecosystems.

• Outbreak areas have faster cycling of calcium, potassium, nitrogen and phosphorous.

• The next major outbreak in Canada is predicted to occur before the year 2000 and could affect 100 million hectares of forest.

Role of Climate/Weather

• Drought increases insect survival through elevated plant nutrient levels, lowered plant defenses and a more suitable physical environment

• Budworms lay 50% more eggs when the temperature is 25ºC than when is is 15ºC.

• Drought stressed plants are average 2-4ºC (+15ºF) warmer than well-watered plants

• Drought and higher temperatures allow budworms to escape the control of some of their natural predators.

• Moths emigrate at night under specific meteorological conditions Moths typically move 50 to 100 km downwind but havemoved as far as 600 km.

Population Control

• Birds consume up to 84% of the larvae and pupae when populations are low, 22% when moderate. Coupled with other predators this can effectively limit the population. They can stop increase and can dampen the seriousness of infestations.

• Once larval density reaches 1 million per hectare natural biological control mechanisms are ineffective.

• Outbreaks start from many reasons. In New Brunswick they occur approximately every 35 years. Environmental stress, especially drought and warmer springs and summers can trigger outbreaks.

• In western portion of range, outbreaks tend to start in mature firs flowering after a hot, dry summer.

• Some outbreaks stop for unknown reasons. In the western portion of the range, outbreaks tend to be stopped by late spring frosts.

Population Control

• Birds consume up to 84% of the larvae and pupae when populations are low, 22% when moderate. Coupled with other predators this can effectively limit the population. They can stop increase and can dampen the seriousness of infestations.

• Once larval density reaches 1 million per hectare natural biological control mechanisms are ineffective.

• Outbreaks start from many reasons. In New Brunswick they occur approximately every 35 years. Environmental stress, especially drought and warmer springs and summers can trigger outbreaks.

• In western portion of range, outbreaks tend to start in mature firs flowering after a hot, dry summer.

• Some outbreaks stop for unknown reasons. In the western portion of the range, outbreaks tend to be stopped by late spring frosts.

Climate Change

• Increasing temperatures and drought probability stress boreal forest species and set up an increasing likelihood of outbreaks.

• Control of outbreaks breaks down. Natural predators are impacted greater than budworms are.

• Alberta, Saskatchewan and Manitoba are all susceptible to drought – most warblers will be lost.

• Probability of late spring frosts declines – outbreaks last longer.

• Wind speed might increase spreading the spruce budworm moths over a greater area (the average wind speed in the central boreal forest of northwestern Ontario has already increased 50%).

• Spruce budworms ca readily adapt to changing conditions. They will be able to follow the migration of the forests.

• Outbreak may extend over 72 million ha and contain 7 x 1015 insects. Even with a mutation rate of 10-5/generation, billions of rare alleles will likely be present in the population.