Authors: Kelsey Reider*, Murray State University, Clifton P. Bueno de Mesquita, University of Colorado Boulder, Kenneth Anderson, Florida International University, Steven K. Schmidt, University of Colorado Boulder
Topics: Mountain Environments, Global Change, South America
Keywords: tropical alpine ecosystems, recently de-glaciated landscapes, primary succession patterns, proglacial soil formation, facilitation, herbivore effects
Session Type: Paper
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Improving knowledge of mechanisms that facilitate primary succession after glacial retreat is urgently required given the rapid pace of glacial retreat in high latitude and high elevation regions. Previous work has demonstrated nutrient limitation severely delays plant community development in glacier forefields. The resulting decoupling between climate and primary succession may make Andean puna grasslands far more vulnerable to range contraction than currently recognized. Our study examined the effect of vicuña (Vicugna vicugna) latrines, communal dung piles, on soil abiotic and biotic properties and plant cover in the rapidly deglaciating Cordillera Vilcanota, southeastern Peru.
Soils within latrines were significantly enriched in all measured edaphic properties compared to control glacial till soils of the same age adjacent to latrines. Organic matter composition, soil moisture, available inorganic nitrogen (nitrate and ammonia), and plant cover were close to zero in glacial till soils, but were significantly greater in latrine soils (paired t-tests, p < 0.05). Likewise, DNA concentrations were almost two orders of magnitude higher in latrine soils (23 ± 9 µg DNA g soil-1) compared to control soils (0.6 ±0.3 µg DNA g soil-1; p = 0.05). Latrine microbial community composition also differed significantly from controls for both bacteria (PERMANOVA, p = 0.004) and eukarya (p = 0.002).
Vicuña latrines shortcut a 100+ year lag between glacier retreat and primary succession. Our results suggest that ecosystem engineering by vicuñas may be an important mechanism by which tropical Andean grasslands can shift upslope at a pace relevant to climate change.
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