Moose Preference of Bark Chlorophyll Content Taylor Mendoza Winter Ecology – Spring 2015 CU Mountain Research Station

Background  Moose (Alces alces) are the largest of Cervidae.  Range: Upper latitudes of North America/Rocky Mountains  Region that is frequented by harsh winters annually.  Non-Migratory  Diet: Leaves and aquatic vegetation  Food Supply is depleted in the winter  Seek alternative sources of energy/nutrients

Moose Incisor Markings  Moose strip bark from trees for feeding during winter (Miquelle and Van Ballenberghe, 1989).  Prefer bark from pulpy trees such as aspen (Chaney 2003).  Why?  Although usually associated with low food availability, bark appears to be nutritious (Reneker and Hudson 1985).  Cambium  Region under outer bark  Succulent cells are a pool for sugars and amino acids (Chaney 2003). 45/ _c514a0d9fa.jpg

Is there more?  Aspen tree bark is rich in chlorophyll.  50% of total photosynthetic surface  May contribute substantially to the annual carbohydrate gains (Marchand, 2014)  Carbohydrates produced may be utilized primarily in the outer layers  Chlorophyll is also rich in nitrogen (Bowman, 2015).  Amount of Chlorophyll in bark varies around the tree (Chaney, 2003).  Would mean a high concentration of carbs and nitrogen in chlorophyll rich areas. CI/AAAAAAAACxk/IEo0cNaHDlE/AspenBarkSchematicCLayer_t humb8.jpg?imgmax=800

Hypothesis  Question:  Do moose select the more nutrient rich region bark of aspen trees when scraping with their incisors?  Hypothesis:  Moose try to limit energy expenditure by going for the most nutrient rich/energy packed bark of aspen trees (that being bark with higher chlorophyll content) therefore, more incisor markings will be observed on more chlorophyll rich areas of bark.  Null Hypothesis  Moose do not select the more chlorophyll rich bark, markings are at random.

Methods  3 Sites  Separated by at least 50 meters and by some other form of vegetation (willow, conifer).  meter transect with boundaries marked by flags.  At each site 7 aspen trees with marks at random were recorded.  Each tree:  Must be marked by a moose.  Data from each moose mark on tree was recorded.  Marks on tree that were not moose were not recorded (e.g., Deer, porcupine)

Only Moose Moose Porcupine

Methods: Data Collection  Chlorophyll content  Recorded concentration chlorophyll around each mark.  Recorded area of highest and lowest content.  Compare green color of trees to a scale of greens using Paint Chips  Scale

Results  Data collected from each site was organized.  Marks were regrouped based on scale  Relative to how close the chlorophyll scale (of the marks) were to the highest and lowest content of the tree.  Example:  If the Highest Scale was an 8, the Lowest Scale a 3, and the mark a 7, then it would fall under the category of high.  Or the reverse, if the mark was a 4 then it would fall under the category of Low.

Results Site # of Marks High Chlorophyll Scale # of Marks Mid Chlorophyll Scale # of Marks Low Chlorophyll Scale A 1014 B 1403 C9 33 ANOVA: Single Factor P- Value:

Discussion  Hypothesis is supported.  There are more marks in areas of higher chlorophyll content than in areas without.  Moose may be picking the bark they ingest based on the amount of energy it offers.  Snow makes mobility difficult and causes the moose to spend more energy while foraging  It would benefit the moose to obtain the most energy that it can at one location.  The high amount of carbohydrates presented by chlorophyll rich areas can supply the moose some of the energy it needs to support its large size.  Aspen disturbances  Reduce aspen numbers  Disrupt chlorophyll  Could interfere with moose feeding habits

Discussion Cont.  Sources of Error  Moose markings may have occurred at different times.  Misidentification of Moose marking  Lighting!  Judging green compared to paint chip  Skew scaling results  Range of scale

Conclusion  Moose need to find alternative forms of food in winter.  Bark stripping supplies nutrients.  Aspen Bark is high in chlorophyll.  Provides Carbohydrates and Nitrogen.  Data shows that moose more frequently strip bark from region of tree with more chlorophyll.  Suggests that moose may be targeting bark with more chlorophyll.

Thank You  Tim Kittel - Helped with ANOVA  Sam Nelson – For company while working on the presentation.  Jake DePompolo – The ride up (Maybe, we almost died…multiple times).  David Block – The ride home.  Jake’s Girlfriend – the $1.00 I needed for BBQ

Works Cited Bowman, Bill. Personal Communication. Feb Chaney, William R. Why Do Animals Eat the Bark and Wood of Trees and Shrubs? Purdue University, Aug PDF. Marchand, Peter J. Life in the Cold: An Introduction to Winter Ecology. 4th ed. Hanover, NH: U of New England, Print. Miquelle, D.G.; Van Ballenberghe, V. Impact of bark striping by moose on aspen-spruce communities. Journal of Wildlife Management :577–5 Risenhoover, K. L., and J. A. Bailey. Foraging Ecology of Mountain Sheep : Implications for Habitat Management. Journal of Wildlife Management :

Appendix ANOVA Source of VariationSSdfMSFP-valueF crit Between Groups Within Groups Total