Abstract Detail

Bryology and Lichenology

Clark, Theresa [1], Russell, Alexander [2], Stark, Lloyd [3].

­­­Escaping the sun: characterizing structural and temporal dynamics of fine-scale shade-buffering on moss-dominated biocrusts using the Sun Seeker app.

In drylands, organisms face stressful extremes in solar irradiance, temperature, and evaporative demand, which are predicted to increase with further climate change. Moss-dominated biocrust diversity and biomass often are higher on shaded microhabitats buffered by vegetation and topography that presumably reduce these climatic extremes, but the structural and temporal dynamics of biocrust shade environments have not been quantified, and the importance of shade-buffering may increase with climate change; therefore, we sought to quantify the shade-buffer and biomass of 134 Syntrichia caninervis-dominated microsites in the Mojave Desert of Nevada, across three scales of aridity and time. We used the iPhone app, Sun Seeker, to delineate time-referenced shade objects from the vantage point of the mosses and created annual, seasonal, and bi-hourly shade-time indices by scoring photos comprising the resulting annual solar-window. We quantified variation in moss shade-time across three life zones (creosote desert, blackbrush-Joshua tree shrubland, pinyon-juniper woodland), three topographical exposures (north-facing, south-facing, flat), and three microhabitat types (shrub canopy, dripline, interspace). To ground these shade-time percentages in units of solar radiation, we quantified insolation and the insolation buffer for mosses at each life zone by establishing PAR light sensors over 12 of the biocrust microsites for comparison to ambient PAR measured by on-site weather stations. Using over 950 photographs, we report the ecological shade-gradient of this common biocrust moss and elucidate its importance in predicting moss, lichen, and total biocrust biomass at fine scales (20 x 20 cm). We report the power of our shade-index to predict seasonal, annual, and bi-hourly solar insolation buffering (i.e. local reduction in PAR). We suggest how these results contribute to a life zone-specific vulnerability assessment for this keystone biocrust moss threatened by climate change, land use, and desertification. We encourage the application of our Sun Seeker shade-index for other biocrust species or vascular plant communities where shade-buffering can inform ecology, restoration, or assisted migration planning. 

1 - University of Nevada, Las Vegas, School of Life Sciences , 4505 Maryland Parkway, Las Vegas, NV, 89154, USA
2 - University Of Nevada, Las Vegas, School of Life Sciences, 4505 Maryland Parkway, Las Vegas, NV, 89154, United States
3 - University Of Nevada, Las Vegas, School Of Life Sciences, Las Vegas, NV, 89154, United States

habitat buffering
climate change
light stress

Presentation Type: Oral Paper
Abstract ID:1046
Candidate for Awards:A. J. Sharp Award

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