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Fryer, Emma [1], O'Dell, Ryan [2], Rajakaruna, Nishanta [1].

Community Assembly of Vertic Clay Endemic Annual Plants of the San Joaquin Desert.

The San Joaquin Desert (SJD) hosts a high diversity of rare, endemic annual plants notable for their massive floral displays following high-precipitation winters. In such years, the blooms on the vertic (smectite) clay soils of the SJD form a distinctive patchwork that is associated with the heterogeneous pattern of soil texture and salinity. These soils are physically extreme due to high clay content, high shrink-swell capacity, and sodicity, which render them inhospitable to most plants. Like species endemic to other extreme substrates (e.g., serpentine) in California, vertic clay endemic species appear adapted to these harsh soils. The non-native annual grass, Bromus madritensis, has invaded the vertic clay ecosystems in some areas and begun to displace the vertic clay endemic species. The combination of a diverse suite of vertic clay endemic species (species pool), extreme abiotic and heterogeneous factors (habitat filter), and the invasion of B. madritensis (competition filter) make this system ideal for studying the factors contributing to plant community assembly. This study will quantify edaphic factors determining fundamental niche for these species through a transplant study of twelve SJD native annuals across three soils (non-sodic, sodic, and extremely sodic vertic clay) and a study of five congener pairs reciprocally transplanted over contrasting soil textures. The role of B. madritensis as a possible biotic factor acting on these species will be addressed by a duplicate soil chemistry study with added B. madritensis plants in each native species’ pot, and thereby determine the realized niche of these species. These combined results will inform a model of the community assembly of the vertic clay endemic flora of the SJD and help shed light on the key adaptations of the flora’s species to these harsh soils.

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1 - California Polytechnic State University, Biological Sciences, 1 Grand Ave, San Luis Obispo, CA, 93407, USA
2 - Bureau of Land Management, Central Coast Field Office, 940 2nd Ave, Marina, CA , 93933, USA
3 - California Polytechnic State University, Biological Sciences, 1 Grand Ave, San Luis Obispo, CA, 93407, USA

edaphic endemism
Rare plants
Native Plants
plant community ecology
vertic clay.

Presentation Type: Oral Paper
Session: ECO4, Ecology: Community Assemblages, Succession and Marcescence
Location: /
Date: Thursday, July 22nd, 2021
Time: 10:15 AM(EDT)
Number: ECO4002
Abstract ID:156
Candidate for Awards:Ecological Section Best Graduate Student Paper

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