How specialized is a soil specialist? Early life history responses of a rare Eriogonum to site-level variation in volcanic soils

Premise of the study: Understanding edaphic specialization is crucial for conserving rare plants that may need relocation due to habitat loss. Focusing on Eriogonum crosbyae, a rare soil specialist in the Great Basin, US, we asked how site-level variation among volcanic soil outcrops affected plant growth and population distribution.

Methods: We measured emergence, survival, size, and biomass allocation of E. crosbyae seedlings planted into soils collected from forty-two outcrops of actual and potential habitat. We also measured phenotypic variation in the wild, documented abiotic and biotic components of E. crosbyae habitat, re-surveyed Nevada populations, and evaluated occupancy changes over time.

Key results: Plants responded plastically to edaphic variation, growing larger and allocating relatively more tissue above-ground in soils with greater nutrient availability, and growing smaller in soils higher in copper in the field and the greenhouse. However, the chemical and physic..., Sampling locations

We assessed current occupancy status and collected and compared soil samples from a subset of 71 previously occupied and 90 unoccupied outcrops across the species’ range in Nevada. The light color and barren nature of E. crosbyae’s preferred volcanic habitat allows it to stand out in comparison with the surrounding landscape, such that potentially suitable habitat can be identified from a distance or using aerial photography. As a result, many potentially suitable sites have been surveyed and have had their occupation status described (Kaye, 1990; Morefield, 2003). Sampling locations for this experiment were chosen primarily from locations compiled in the Conservation Status Report for E. crosbyae (Morefield, 2003), and were last surveyed during (two sites) or prior to (thirty-three sites) 1993. Additional sampling locations were included based on survey locations documented in the Consortium of Intermountain Herbaria (USA) online repository (http://intermountainbi..., Please see 'ReadMe.txt' for descriptions of the contents of each worksheet within the dataset.