Abstract Detail

Ecological Section

Rossington, Natalie [1].

Investigating the spatial distribution and reproductive barriers between Layia jonesii, a rare serpentine endemic, and L. platyglossa in San Luis Obispo, California.

Some rare plants are able to secure habitat despite fierce resource competition from surrounding species, and are also able to maintain reproductive isolation even though interspecfic fertility may exist. Investigating these spatial and reproductive boundaries between closely related plant taxa helps us to understand how these barriers are maintained, particularly when taxa grow sympatrically or parapatrically.  San Luis Obispo County offers immense plant diversity and a high density of rare, understudied taxa. Layia jonesii, a rare San Luis Obispo County serpentine endemic, and L. platyglossa are two related taxa in the tarweed genus. These two species grow parapatrically on serpentine derived soil in Reservoir Canyon and do not produce observable hybrids. We studied this system to investigate possible mechanisms contributing to the maintenance of spatial and reproductive barriers. We hypothesized edaphic specialization maintains spatial barriers and flowering time differences contribute to reproductive isolation. To investigate the spatial barrier between L. jonesii and L. platyglossa at Reservoir Canyon, we reciprocally transplanted both species into the core of each species distribution. We compared survivorship and fitness of each species within and outside its natural distribution to determine if either species showed edaphic specialization in its particular habitat. We also conducted a competition experiment to determine if L. jonesii is sensitive to resource competition beyond its natural distribution. To investigate reproductive barriers, we tracked flowering time of both wild and reciprocally transplanted populations. Results show edaphic specialization maintains spatial distributions of L. jonesii and L. platyglossa in Reservoir Canyon. Layia jonesii is tolerant of harsh shallow, dry, and rocky serpentine soils with limited competition from other taxa while L. platyglossa is not tolerant of these soils. We also documented earlier flowering time L. jonesii  than L. platyglossa in both wild and reciprocally transplanted populations. This acts as a strong barrier to reproduction by reducing interspecific gene flow. These results provide insight into mechanisms that maintain spatial and reproductive boundaries between closely related taxa existing in similar habitats. The results also contribute to our understanding of how rare plants preserve genetic integrity and ensure habitat availability. 

1 - 306 Yerba Buena St, Morro Bay, CA, 93442, USA

Keywords:
rare species
plant ecology
reciprocal transplant.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Eyrie/Boise Centre
Date: Monday, July 28th, 2014
Time: 5:30 PM
Number: PEC011
Abstract ID:273
Candidate for Awards:Ecological Section Best Graduate Student Poster,Ecological Section Best Undergraduate Presentation Award