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ORCID
https://orcid.org/0009-0009-5148-7457
Date of Graduation
5-15-2026
Semester of Graduation
Spring
Degree Name
Master of Science (MS)
Department
Department of Biology
First Advisor
Kelsey Reider
Abstract
Rapid glacial retreat in the high tropical Andes exposes bare, rocky landscapes, triggering primary succession and colonization by new ecological communities. In arid, high-elevation environments, poorly developed, nutrient-limited soils limit plant colonization following glacier retreat. While facilitation by microbes and nurse plants are well-known to influence early plant communities, studies of plant primary succession have largely overlooked the potentially important effects of animal-modified nutrient and biodiversity hotspots. We evaluated the effects of native camelid communal dung piles on glacier forefield ground cover, plant diversity and community structure by comparing animal-modified patches to unmodified moraine reference sites in three glacier forefields in the rapidly deglaciating Cordillera Vilcanota, southeastern Peru. We compared diversity and community structure across elevational gradients and a ~125 year chronosequence of glacier retreat, and investigated indicator species and plant differential abundance. We also explored overlap between plant species occurrence in each habitat type and vicuña diet. Biotic ground cover (plants, lichen, moss, and organic matter) was higher on latrines than reference sites, while abiotic cover (rocks, soil, and gravel) and biological soil crust were higher on references across chronosequence age classes. In areas exposed by retreating glaciers recently (< 125 years), plant richness was significantly higher on animal–modified patches than reference moraines, but richness did not differ on substrates exposed longer than 125 years. Latrine plant diversity was negatively correlated with camelid activity intensity. Of 49 plant species in recently deglaciated areas, 12 were exclusively on latrines, 13 on reference moraines, and 24 in both habitats. Plant community structure differed between animal-modified patches and reference moraines across chronosequence age classes and three glacier forefields. Camelid latrines were characterized by indicator species including forbs and grasses eaten by native Andean camelids. Reference moraine indicator species are among the earliest glacier forefield pioneers. Glacial forefield plant diversity and community structure are strongly influenced by animal-modified habitat patches despite their small size. Camelid latrines facilitate plant establishment and accelerate primary succession, host distinct plant communities, and may promote seed dispersal. The diverse plant habitats also likely provide critical resources for animal communities after glacier retreat.
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