Relationship Between Biological Soil Crusts and Desert Shrub ...

Relationship Between Biological Soil Crusts and Desert Shrub Cov Presented By: Matthew Bridges (UC Davis), Kea Rutherford (UC Berkeley), Zach Jordan (UC Santa Cruz), Sandy Gad (UC Riverside), Tiffany Alvarado (UCLA) Lets Talk About Soil Civilization rise and fall Easter Island- sound familiar?

NONRENEWABLE resource Desert Soil Crusts Major Functions of Soil Crusts Research Question Central Question: What is the relationship between soil crust

thickness and aspect on shrub cover? Explanatory Variable: Soil crust thickness Explanatory Variable: Aspect Response Variable: shrub percent coverage Covariate (explanatory): soil moisture Methods Crust thickness sample

must be taken with a quadrat Vegetation measured using a line-intercept transect of 30m Random number (1-20) selection

out of a plastic bag Estimate center of hill for starting point Soil moisture sample taken at 15m mark of

transects 2 &204 10 m 10 m 10

m m * Haphazard slope selection * Throw a rock to

determine starting point o flats 20 m 20 m

Soil crust thickness taken at 10m & Starting height randomly generated

Transects Line-Intercept Method Calculating percent vegetation cover Vegetatio n Cover = Length covered by

vegetation Length of transect Quadrats Determining Soil Moisture Content Weigh out 200g of soil Baked soil

Weigh baked soil Use (Wa - Wb)/Wa Results Question: What is the relationship between soil crust thickness on shrub cover?

p>0.10 R^2=0.0013 B A A

p<0.01 B B A p<0.01

A B B p=0.001

Interpretation Average soil crust thickness v. Aspect: Flash floods and annual crust disturbance Water content v. Aspect: Largest particles stay in wash Low retention

Shrub coverage v. Aspect: Vegetation capitalization Connections to Other Research 0.1 R^2=0.098 Ram et. al 2006 suggest that

thicker soil crusts decrease plant available moisture Soil Crusts and Climate Change Red areas indicate high C fixation from Cryptobiotic crusts L.G. Sancho et al.

Thank You! Citations Ram, Almog, and Yair Aaron. Negative and Positive Effects of Topsoil Biological Crusts on Water Availability along a Rainfall Gradient in a Sandy Arid Area. CATENA 70, no. 3 (August 1, 2007): 43742. doi:10.1016/j.catena.2006.11.012.

Zhang, Yuanming, Asa L. Aradottir, Marcelo Serpe, and Bertrand Boeken. Interactions of Biological Soil Crusts with Vascular Plants. In Biological Soil Crusts: An Organizing Principle in Drylands, edited by Bettina Weber, Burkhard Bdel, and Jayne Belnap, 226:385406. Cham: Springer International Publishing, 2016. doi:10.1007/978-3-319-30214-0_19.