Project Details

Welsh's milkweed (Asclepias welshii) is a federally listed threatened species that is endemic to active aeolian sand dunes in southern Utah and northern Arizona. The plant is a robust herbaceous perennial that spreads via underground rhizomes to form patches that migrate with the dunes. Although plants can potentially reproduce from seed, most spread is by clonal propagation. There are eight known populations, but ca. 98% of plants are in the population at CPSD. Primary threats to this population include OHV impacts and dune stabilization, but population size based on stem counts has increased through time there, prompting managers to consider delisting as a possible option.

In the latest five-year review, the USFWS (2015) recommended more extensive surveys and improved monitoring as the highest priority needs for this species. Specifically, monitoring protocols need to be refined to account for the shifting nature of the dunes, to address the impacts from OHVs, and to distinguish or define individual genets versus stem numbers. We have demonstrated that drone-based protocols can be effective for survey, census and monitoring of plants in sparsely vegetated habitat (Rominger and Meyer 2019, Rominger et. al. in press). Drone technology provides a time-efficient and economical way to carry out surveys to locate new populations, to determine current population status through census, and to monitor to detect population trends through time that are critical to extinction risk assessment.

Another high priority need for Welsh's milkweed is to acquire a better understanding of its genetic structure and levels of genetic diversity. Without some assessment of the level of genetic diversity within and among populations, it is not possible to evaluate extinction risk. In a strongly clonal species like Welsh's milkweed, where genetic individuals cannot be identified morphologically, molecular markers are the only nondestructive way to accomplish this assessment. An earlier effort to use microsatellite markers from another milkweed species was unsuccessful, but next-generation sequencing technology will make a straightforward genetic evaluation readily achievable.

Provide evidence about the nature of the problem and the need to address it. Identify the significance of the problem using a variety of data sources. For example, if a habitat restoration project is being proposed to benefit greater sage-grouse, describe the existing plant community characteristics that limit habitat value for greater sage-grouse and identify the changes needed for habitat improvement.

Provide an overall goal for the project and then provide clear, specific and measurable objectives (outcomes) to be accomplished by the proposed actions. If possible, tie to one or more of the public benefits UWRI is providing.

LOCATION: Justify the proposed location of this project over other areas, include publicly scrutinized planning/recovery documents that list this area as a priority, remote sensing modeling that show this area is a good candidate for restoration, wildlife migration information and other data that help justify this project's location.

TIMING: Justify why this project should be implemented at this time. For example, Is the project area at risk of crossing an ecological or other threshold wherein future restoration would become more difficult, cost prohibitive, or even impossible.

List management plans where this project will address an objective or strategy in the plan. Describe how the project area overlaps the objective or strategy in the plan and the relevance of the project to the successful implementation of those plans. It is best to provide this information in a list format with the description immediately following the plan objective or strategy.

If applicable, detail how the proposed project will significantly reduce the risk of fuel loading and/or continuity of hazardous fuels including the use of fire-wise species in re-seeding operations. Describe the value of any features being protected by reducing the risk of fire. Values may include; communities at risk, permanent infrastructure, municipal watersheds, campgrounds, critical wildlife habitat, etc. Include the size of the area where fuels are being reduced and the distance from the feature(s) at risk.

Describe how the project has the potential to improve water quality and/or increase water quantity, both over the short and long term. Address run-off, erosion, soil infiltration, and flooding, if applicable.

Description of efforts, both completed and planned, to bring the proposed action into compliance with any and all cultural resource, NEPA, ESA, etc. requirements. If compliance is not required enter "not applicable" and explain why not it is not required.

Objective 1) Our methodology for image acquisition, processing and analysis as well as our experimental design approach to census and monitoring is described in the attached documents (Rominger and Meyer 2019, Rominger et al. in press). We will carry out exploratory image acquisition and analysis in summer 2021 at CPSD to adapt our existing protocols and make sure they will work for this species. We will fly at multiple altitudes to determine the best altitude for resolving maximum detail and obtaining the best information on stem status (vegetative vs. reproductive) and spatial configuration.

Objective 2) To carry out a first year of monitoring we will obtain detailed location information for existing monitoring plots at CPSD and design flight plans that include these plots as well as  extensive surrounding areas, including stabilized dunes versus active dunes and areas open to and closed to ORVs. Using drone imagery obtained during flowering in 2022, we will determine the density and map the spatial distribution of vegetative and reproductive stems across much larger areas than those included in the existing monitoring plots. We will include validation on the ground of the accuracy of our image interpretation. We will also compare our results directly to on-the-ground monitoring, assuming the monitoring data are made available to us. We will also work on methods for following dune movement and stabilization through time as well as for evaluating ORV impacts from the imagery.

Objective 3) We will obtain drone imagery at the optimal altitude for census over the entire Sand Hills population in mid-summer 2021 and quantify the current number of stems in the population. We will also map the spatial distribution of Welsh's milkweed stems relative to each other and to environmental variables such as dune configuration and total plant cover at this population.

Objective 4) In consultation with the Kanab Field Office of the BLM, we will identify 5-10 priority dune areas to survey for new populations of Welsh's milkweed. Our goal will be to determine whether the species is detectable in the imagery, based on our evaluation of imagery taken at the same altitude in known populations of the species (i.e., Sand Hills). Depending on accessibility, any new occurrences can potentially be verified through ground reconnaissance or through drone flights at lower altitude.

Objective 5) Conservation-based genetic studies of rare clonal species have been recently accomplished by sequencing a reduced representation of the genome (Amor et al. 2020), through a process known as double-digest restriction-site associated DNA sequencing (ddRADSeq). RADSeq and ddRADseq are techniques that efficiently and inexpensively identify genetic variation across any genome, including those of non-model organisms (Peterson et al. 2012). The techniques are effective because they combine restriction enzymes that systematically cut the DNA with next-generation sequencing that identifies the sequence of base-pairs in the cut fragments. The data are analyzed with software such as GENALEX 6.5 to remove any SNPs (single nucleotide polymorphic loci)  that deviate from Hardy-Weinberg equilibrium, and BAYESCAN v. 2.1 to remove SNPs under balancing and divergent selection (Nazareno et al. 2017), ensuring that the analysis is based solely on neutral genetic variation. Population structure, inbreeding coefficients, and heterozygosity are calculated with GENALEX 6.5, and estimated pairwise genetic differentiation (FST) with SPAGeDi software (Hardy and Vekemans, 2002). We will use this approach in our molecular genetic study of Welsh's milkweed population structure. 
Sampling for our study of clonal structure and genetic diversity in Welsh's milkweed will involve the creation of a grid over a single "population" of milkweeds at CPSD followed by tissue sampling of leaves from stems within each cell of the grid. Grid cell size will be determined by estimations from previous studies of approximate milkweed runner lengths, and sample locations can be marked and recorded by drone. Tissue samples will consist of 1 cm2 of green non-senescent leaves dried on silica gel and stored at room temperature. DNA will be extracted with a Qiagen DNeasy Plant Pro kit according to the manufacturer's instructions and shipped to an external provider such as Floragenex or Oregon State University for specialized ddRADSeq analysis. Jacqualine Grant and students at Southern Utah University will perform bioinformatics to assess clonal structure and determine next steps for more in depth and/or wider scale genetic analyses across multiple populations.

Describe the actions, activities, tasks to be implemented as part of the proposed project; how these activities will be carried out, equipment to be used, when, and by whom.

Describe plans to monitor for project success and achievement of stated objectives. Include details on type of monitoring (vegetation, wildlife, etc.), schedule, assignments and how the results of these monitoring efforts will be reported and/or uploaded to this project page. If needed, upload detailed plans in the "attachments" section.

List any and all partners (agencies, organizations, NGO's, private landowners) that support the proposal and/or have been contacted and included in the planning and design of the proposed project. Describe efforts to gather input and include these agencies, landowners, permitees, sportsman groups, researchers, etc. that may be interested/affected by the proposed project. Partners do not have to provide funding or in-kind services to a project to be listed.

Detail future methods or techniques (including administrative actions) that will be implemented to help in accomplishing the stated objectives and to insure the long term success/stability of the proposed project. This may include: post-treatment grazing rest and/or management plans/changes, wildlife herd/species management plan changes, ranch plans, conservation easements or other permanent protection plans, resource management plans, forest plans, etc.

Potential for the proposed action to improve quality or quantity of sustainable uses such as grazing, timber harvest, biomass utilization, recreation, etc. Grazing improvements may include actions to improve forage availability and/or distribution of livestock.