Create your own conference schedule! Click here for full instructions

Abstract Detail


Brown Marsden, Margaret [1].

Seasonal variation, soil associations, and geographical distribution in Hexalectris orchids.

Hexalectris is a genus of mycoheterotrophic orchids found primarily in the southwestern United States and Mexico with a limited range and some species considered of conservation concern within the state and globally. Details on the evolutionary relationships between Hexalectris and symbiotic fungi are known, but relatively little is understood about the ecological factors that affect geographical distribution and seasonal variation in populations. Past studies of Hexalectris indicated a possible role between spring rainfall and orchid numbers, as well as broad descriptions of prospective orchid habitat. Over a ten-year period a research team supported by local master naturalist volunteers conducted a detailed study of the relationship between Hexalectris numbers and annual rainfall and between documented orchid locations and pedological/geological characteristics. However, during this ten-year period Hexalectris census numbers showed a strong relationship to previous year’s total rainfall rather than spring rainfall. This relationship suggests a possible link between inflorescence numbers and carbon sequestration during wet years. Targeted searches informed by knowledge of soil type were highly successful, and helped to locate ten new Hexalectris populations in Dallas County. Targeted searches also led to a range expansion in H. grandiflora, a species previously unknown outside of western Texas. Hexalectris diversity is correlated with preserve area, demonstrating that a larger preserved site could help conserve more Hexalectris species. Soil surveys, geological data and known Hexalectris locations in Texas helped to identify 64 counties with soil and geological conditions that could be associated with Hexalectris. Many of these counties have no records of Hexalectris, showing the potential need for and value of targeted searches during wetter, more productive years to aid in identifying new populations to help fill in Hexalectris distributions and direct future conservation efforts. A conservation plan guided by climate and soil/geological data could assist in ensuring possible Hexalectris sites might be protected prior to development to ensure population persistence.

Log in to add this item to your schedule

1 - Midwestern State University, College of Science and Mathematics/Biology Department, 3410 Taft Boulevard, Wichita Falls, TX, 76308, United States

soil associations

Presentation Type: Oral Paper
Session: 11, Ecology Section - Population Biology
Location: Sundance 5/Omni Hotel
Date: Monday, June 26th, 2017
Time: 3:00 PM
Number: 11007
Abstract ID:48
Candidate for Awards:None

Copyright © 2000-2017, Botanical Society of America. All rights reserved