Influences of Stationary Objects on Winter Subnivean Micro-Environments David Olson - Ebio 4120 – Spring 2010 Source: freestockphotos.com Winter Ecology Mountain Research Station, University of Colorado, Boulder

Micro-Environment Intro & Definition  Even small changes in the abiotic environment can hurt or help life during winter  Question  Can certain objects influence the environment immediately around them in noticeable manners?  Hypothesis and Prediction  Objects and debris can cause differences in snow pack around their perimeter  Measurable differences in snow structure will exist along the North, South, East and West sides of a boulder or large tree  “… microhabitat is defined as the ecological conditions that immediately encompass an individual …” – “… high natural ecological specificity has been shown to limit the distribution of a number of … species …”  (Elle, 2009)

Why Study?  Will over-wintering species be able to take advantage (or be harmed) by microenvironments?  Will different microenvironments be able to support a range of microfauna within a range of small diameter?  “The study of specific physiognomic and structural …microhabitat features … seems to … reveal specific [species] habitat requirements …”  (Pantis, 2009)  “ [Downed woody material] also increases the structural complexity of the forest floor and creates several unique habitats, and … species diversity has been shown to be positively correlated with microhabitat structural diversity ”  (Buddle, 2010)

Experiment & Methods  Site identification  Debris or obstacle of diameter ~ > 0.5m  Digging Snow Pits  North, South, East and West directions. ~ 50cm from object  Measurements  Depth, Density, Temperature, Crystal shape and hardness, Layer structure  Control  Identification of control site. Stand structure similar to previous, sans obstacle  Analysis  t-test to compare mean differences in data against control Source: nasa.gov

Results – Temperature Gradients North East South West

Results - Weight NorthEast WestSouth

Results – Analysis T-Test: Temperatures (°C) NorthSouthEastWest Average PROB- Value Control Average: T-Test: Weight (g) Control Average: NorthSouthEastWest Average PROB- Value

Results – Analysis T-Test: Grain Hardness NorthSouthEastWest Average PROB- Value Control Average: T-Test: Grain Size (mm) Control Average: NorthSouthEastWest Average PROB- Value

Discussion  Differences appear to exist between the four individual directions  Experimental error  Is this significant?  How could it be more so?  Implications  Where might biology be found  How can abiotic factors influence winter biota  Further work  More iterations  Can we actually find different communities in the snowpack?  If so how do they interact with eachother and the greater environment?

Final Notes  Contributions to forest types  Implications of forest structure on microfauna and chemistry  Implications on forest restoration  Debris from clearing  Impacts of heavy machinery and moving of obstacles

Literature Cited  Buddle, and Andrea Dechene. “Decomposing logs increase oribatid mite assemblage diversity in mixedwood boreal forest.” Biodiversity and Conservation 19.1 (2010): Illumina. Web. 19 Feb  Elle, and Rachel Mayberry. “Effects of forest structure and microhabitat on the distribution and flowering of a rare understory plant, Actaea elata.” Forest Ecology and Management (2009): ScienceDirect. Web. 18 Feb  Pantis, Sgardelis, et al. “Microhabitat Selection by Three Common Bird Species of Montane Farmlands in Northern Greece.” Environmental Management 44.5 (2009): Illumina. Web. 19 Feb