Arizona

Kim McCue, Shannon Felberg and Steve Blackwell
Desert Botanic Garden

Date Recorded: 
Friday, May 4, 2018

Shannon Fehlberg,Desert Botanical Garden

The Acu–a cactus, Echinomastus erectocentrus var. acunensis, is an endangered species with a restricted distribution in the Sonoran Desert in southern Arizona and northern Sonora, Mexico. Population-level genetic analyses for this species are lacking, and taxonomic boundaries between E. erectocentrus var. acunensis and its close relatives E. erectocentrus var. erectocentrus and E. johnsonii are unclear. Detailed morphological data that have been collected for these three taxa indicate the existence of a geographical cline from the Mojave Desert to the Sonoran Desert. The goal of this project is to document genetic diversity within and among populations of E. erectocentrus var. acunensis, as well as between E. erectocentrus var. acunensis and its close relatives. The addition of genetic data to our current knowledge of morphology and distribution may enable us to form stronger species definitions, make more accurate field identifications, and begin to clarify taxonomic confusion in the group. To acquire genetic data, seven known populations of E. erectocentrus var. acunensis, three populations of E. erectocentrus var. erectocentrus and four populations of E. johnsonii were visited, and more than 230 spine or floral tissue samples were taken. DNA was extracted, and data were collected for 11 microsatellite regions specifically developed for these taxa, and two microsatellite regions previously developed for Sclerocactus. Standard population genetic measures were used to determine genetic variation and structure, and observed genetic differentiation was compared to the current morphological understanding of the group. These analyses help improve our knowledge of the genetic structure of E. erectocentrus var. acunensis populations and inform our understanding of species boundaries and evolutionary relationships within the group, thereby allowing us to refine conservation and management plans aimed at protecting and restoring populations of this endangered species.

Contributing Author(s): 
Date Recorded: 
Friday, May 3, 2019

Kristin E. Haskins and Sheila Murray (The Arboretum at Flagstaff), and Andrea Hazelton (Desert Butte Botany)

Acquisition of a long-term dataset is truly rare and can represent decades of hard work and thousands of dollars or more in exhausted resources. The standard model of monitoring year after year is unsustainable for most organizations and begs the question, when should it stop? The Arboretum at Flagstaff has a demography data set for Arizona cliffrose (Purshia subintegra) that has been on-going since 1996. Different ‘levels’ of monitoring have occurred over the years depending on available resources. With some recent funds, we set out to address the following questions with long-term data: 1) What is the long-term viability of the population? 2) Which life stages are most important to capture in the monitoring? And 3) can we monitor less often and still capture important life history events? Challenges included determining starting population sizes for population matrix models and gaps in data. Using the 22 years of monitoring data combined with data from published papers, anecdotes, and historic weather data, we produced population growth rates for P. subintegra and identified key life stages correlated with precipitation events, thus enabling implementation of a modified monitoring protocol, which will conserve valuable resources.

Contributing Author(s): 
Date Recorded: 
Friday, May 4, 2018