1 / 31

Baltimore Oriole

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,

harveyfrank
Télécharger la présentation

Baltimore Oriole

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Baltimore Oriole

  2. Ring-Necked Pheasant

  3. State-colored Junco

  4. Great-tailed Grackle

  5. Magnolia Warbler

  6. Blackburnian Warbler

  7. Black-throated Green Warbler

  8. In 2001, more than 1.9 million Minnesota spent $532 million watching wildlife. – 2001 National Survey of Fishing Hunting, and Wildlife-Associated Recreation

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

More Related