Implications of Beetle Killed Lodgepole Pine Effects on the Red Squirrel in Winter

1. Implications of Beetle Killed Lodgepole Pine Effects on the Red Squirrel in Winter Taylor Loen Winter Ecology Spring 2009 University of Colorado Boulder Mountain Research Station

2. Introduction • Front Range Lodgepole pine (Pinus contora) forest is a major habit for the Red Squirrel (Tamiasciurus hudsonicus fremonti) because of the predicted availability of the cone supply.(Finley. 1969) • The bark beetle (Dendroctonus ponderosae) infestation reduces the number of viable lodgepole pine. Dead trees are known as beetle kill trees.

3. Parameters • Q1: What is the relationship between pop. of R. Sqs and the density of BK trees? • Q2: What is the relationship between frequency of interaction with BK tree and BK tree density? • Q3: How are the bk trees in H density areas being used?

4. ResultsQ1: What is the relationship between pop. of R. Sqs and the density of BK trees? • R. Sq population is lower in stands of high density bk trees.(Koprowski 2005) (Matsuoka 2001) • Thinned stands of lodgepole provide less food, and less protection to predation than medium or high density stands of healthy trees. (Sullivan & Moses 1986) • Average home range is about .56 ha = 5,600 m2= 1.38 acres. Average density was 1.3 sq/ha (Gurnell 1984)

5. ResultsQ2: What is the relationship between frequency of interaction with BK tree and BK tree density? • Likelihood of interaction increases 3.3% - 5.5% per beetle attacked/killed tree in the squirrels home range. (Pretzlaw. 2006)

6. ResultsQ3: How are the bk trees in H density areas being used? • Bk trees are used as foraging sites for bark beetle larvae. (Pretzlaw 2006) • Encounter rate determines the time it takes for the squirrel to develop a prey model for the beetle larvae. (Getty 1993; Tinbergen 1960)

7. Discussion • Red Squirrel ranges are dependent on the food available, therefore reducing the number of cone producing trees will impact their survival in that area. (Rusch & Reeder 1978) • Their winter survival is highly dependent on their midden stores to last them through a winter.(M. Smith 1968, Streubel 1968)

8. Discussion Cont. • Beetle killed lodgepole pines change the dispersal of the squirrels in the area, but also increase the likely hood of the squirrels interacting in some way with bk trees. Which could change the seasonal diet of the squirrel allowing it to save the cones for the winter, since beetle larvae are not cached.(Pretzlaw 2006) • The inherent loss of trees will effect a novel change in the habits of the front range red squirrel.

9. Summary • High density bk trees/thinned stands of lodgepole have lower populations of R. squirrels. • The more bk trees there are the more likely the interaction. • Red Squirrels may feed on beetle larvae. • Reduced number of lodgepole means more competition for cones of other species. • Winters will be tougher because of fewer available lodgepole cones for storage.

10. References • Finley, R B. Jr. 1969. Cone Caches and middens of Tamiasciurus in the Rocky mountain Region. Univ. Kansas Mus. Nat. Hist. Misc. Publ. 51, 233-273. • Getty, T. 1993. Search tactics and frequency dependent prey detection. American Naturalist 141:804-811. • Gurnell, John. (1984) Home Range, Territoriality, Caching Behavior and Food Supply of the Red Squirrel (Tamiasciurus Hudsonics Fremonti) in a Subalpine Lodgepole Pine Forest. Animal Behavior. 32, 1119-1131. • Hosley, N. W. 1928. Red squirrel damage to coniferous plantations and its relation to changing food habits. Ecology 4:43-48. Klugh, A Brooker. (1927) Ecology of the Red Squirrel. Journal of Mammalogy, 8, 1-32. • Koprowski, J. L., M. I. Alanen, & A. M. Lynch. 2005. Nowhere to run and nowhere to hide: response of endemic Mt. Graham red squirrels to catastrophic forest damage. Biological Conservation 126:491^98. • Matsuoka, S. M., C. M. Handel, & D. R. Ruthrauff. 2001.Densities of breeding birds and changes in vegetation in an Alaskan boreal forest following a massive disturbance by spruce beetles. Canadian Journal of Zoology 79:1678-1690. • Panjabi, Arvind. Field Lecture; Birds of the Front Range Montane Forest and their Winter Ecology. February, 15 2009. • Pike, G. W. 1934. Girdling of ponderosa pine by squirrels. Journal of Forestry 32:98-99. • Pretzlaw, Troy. (2006) Red Squirrels (Tamiazcuirus Hudsonicus) Feeding on Spruce Bark Beetles (Dendroctonus Rufipennis): Energetic and Ecological Implications. Journal of Mammalogy, 87, 909-914. • Rusch, D.A. & Reeder, W. G. 1978. Population ecology of Alberta red squirrels. Ecology. 59, 400-420 • Smith, C. C. 1970. The coeveolution of the pine squirrels (Tamiasciurus) and Conifers. Ccol. Monogr. 40, 349-371. • Smith, M. C. 1968, Red Squirrel response to spruce cone failure in interior Alaska. Journal of Wildlife Management. 32, 305-317. • Steele, M. A. 1998. Pine squirrel (Tamiasciurus hudsonicus). Mammalian Species 586:1-9. • Strubel, D. P. 1968. Food Storing and related Behavior of Red Squirrels (Tamiasciurus husonicus) in interior Alaska. M.S. thesis, University of Alaska. • Sullivan, T. P., J. A. Krebs, & P. K. Diggle. 1994. Prediction of stand susceptibility to feeding damage by red squirrels in young lodgepole pine. Canadian Journal of Forest Research 24:14-20. • Sullivan, T. P., J. A. Krebs, & P. K. Diggle. (1996) Response of Red Squirrels and Feeding Damage to Variable Stand Density in Young Lodgepole Pine Forest. Ecological Applications. 6, 1124-1134. • Sullivan, T. P., and R. A. Moses. 1986. Red squirrel populations in natural and managed stands of lodgepole pine. Journal of Wildlife Management 50:595-601.