Below is the Executive Summary, go here to view the complete 77-page Running Buffalo Clover Revised Recovery Plan (PDF)

Running Buffalo Clover Recovery Plan: First Revision

Executive Summary

Current Species Status: Running buffalo clover (Trifolium stoloniferum) occurs in 101
populations in three geographical regions: Appalachian (West Virginia and southeastern Ohio), Bluegrass (southwestern Ohio, central Kentucky and Indiana), and the Ozarks (Missouri). The majority of populations occur within the Appalachian and Bluegrass regions, with the largest population in West Virginia and the most populations in Kentucky. Running buffalo clover was listed as endangered in 1987. At the time of listing only one population was known; in 1989 when the original recovery plan was completed, running buffalo clover was known from 13 populations. This is the first recovery plan revision.

Habitat Requirements and Limiting Factors: Running buffalo clover occurs in mesic habitats of partial to filtered sunlight, where there is a prolonged pattern of moderate periodic disturbance, such as mowing, trampling, or grazing. It is most often found in regions underlain with limestone or other calcareous bedrock. The primary threat to running buffalo clover is habitat alteration. Factors that contribute to this threat include natural forest succession, and subsequent canopy closure, competition by invasive plant species, permanent habitat loss through development or road construction, and may include the elimination of bison and other large herbivores.

Recovery Strategy: Running buffalo clover was listed under the Endangered Species Act (ESA) because the few known populations were threatened by habitat alteration. Current threats to the species include habitat destruction, habitat succession, and invasive plant competition. In addition to these threats, inherent biological vulnerabilities for this species include its reliance on pollinators, seed scarification, and dispersal mechanisms as well as a dependence on disturbance.

Since its listing in 1987, several positive outcomes have been realized due to recovery implementation: 1) more information is available regarding the species biology; and 2) the known number of populations has dramatically increased as survey efforts have expanded throughout the historic range. Although many of the threats to running buffalo clover populations still exist, some initially identified potential threats do not appear to be a risk to the species.

Recovery of running buffalo clover will be achieved by implementing actions which address the species distribution, numbers, and threats. Given the known threats and constraints, this recovery effort focuses primarily on increasing the number of protected and managed populations, determining the viability of existing populations, and research into the species ecological requirements. Key to this strategy is the protection and ecological management of various-sized populations of running buffalo clover throughout its geographic range. The recovery criteria and subsequent recovery actions rely heavily on retaining and managing the habitats on which running buffalo clover needs to maintain viability. In addition, the recovery strategy relies on a greater understanding of the biotic and abiotic needs of running buffalo clover. Numerous scientific studies have started to shed light on the ecological requirements of running buffalo clover, but more information is needed to understand the level of periodic disturbance required to maintain the species.

In order to reclassify and eventually delist running buffalo clover, adequate numbers and sizes of populations need to be monitored, protected, and managed and the ecological factors that regulate the populations need to be further defined. Additionally, until these population regulation factors are better understood, the genetic diversity of known populations of all sizes should be conserved.

Recovery Goal and Objectives: The ultimate goal of this recovery program is to remove running buffalo clover from the Federal List of Threatened and Endangered Plants (50 CFR 17.12), with an intermediate goal of reclassification to Threatened. To merit delisting, a minimum number of viable populations should be protected and managed throughout a majority of the species geographic range. Populations are considered protected when there are permanent assurances that the habitat will be managed. Management objectives for running buffalo clover include 1) controlling invasive species, 2) reducing habitat succession, and 3) defining population regulation factors. Additional recovery objectives include 1) ensuring viability of protected populations, 2) maintaining genetic diversity and germplasm, and 3) promoting public understanding of the species.

Recovery Criteria: Running buffalo clover may be reclassified from endangered to threatened when the following criteria are met. Numerical goals are based on most recently available scientific information and are subject to revision as new information becomes available.

1. Seventeen populations, in total, are distributed as follows: 1 A-ranked, 3 B-ranked, 3 Cranked, and 10 D-ranked populations across at least 2 of the 3 regions in which running buffalo clover currently occurs (Appalachian, Bluegrass, and Ozark). The number of populations required in each rank is based on what would be necessary to achieve a 95% probability of persistence within the next 20 years based on population viability analysis (see Appendix 5). Rankings refer to the Element Occurrence (EO) ranking categories (Table 1).

2. For each A-ranked and B-ranked population described in #1, population viability analysis indicates a 95% probability of persistence within the next 20 years, OR for any population that does not meet the 95% persistence standard, the population meets the definition of viable. For downlisting purposes, viability is defined as follows: A) seed production is occurring; B) the population is stable or increasing, based on at least five years of censusing; and C) appropriate management techniques are in place.

3. The land on which each of the populations described in #1 occurs is owned by a government agency or private conservation organization that identifies maintenance of the species as one of the primary conservation objectives for the site, OR the population is protected by a conservation agreement that commits the private landowner to habitat management for the species. Natural Resource Management Plans on Federal lands may be suitable for meeting this criterion. This criterion will ensure that habitat-based threats for the species are addressed (see Appendix 6). Running buffalo clover may be removed from the List of Endangered and Threatened Plants (50 CFR 17.12) when the following have been met:

1. Thirty-four populations, in total, are distributed as follows: 2 A-ranked, 6 B-ranked, 6 Cranked, and 20 D-ranked populations across at least 2 of the 3 regions in which running buffalo clover occurs (Appalachian, Bluegrass, and Ozark). The number of populations in each rank is based on what would be required to achieve a 95% probability of persistence within the next 20 years; this number was doubled to ensure biological redundancy across the range of the species.Rankings refer to the Element Occurrence (EO) ranking categories (Table 1).

2. For each A-ranked and B-ranked population described in #1, population viability analysis indicates 95% probability of persistence within the next 20 years, OR for any population that does not meet the 95% persistence standard, the population meets the definition of viable.1 For delisting purposes, viability is defined as follows: A) seed production is occurring; B) the population is stable or increasing, based on at least 10 years of censusing; and C) appropriate management techniques are in place.

 

3. Downlisting criterion #3 is met for all populations described in delisting criterion #1.

Actions Needed:

1. Conserve and manage running buffalo clover populations and the habitat on which they depend.
2. Define population regulation factors.
3. Conserve germplasm and genetic diversity.
4. Promote public understanding.
5. Review and track recovery progress.

Estimated Cost of Recovery (in $1,000’s) for first five years:

Date of Recovery: Recovery could occur by 2020 if recovery criteria are met and with
adequate funding.

Footnote 1: C-ranked and D-ranked populations are not included for the purposes of viability in recovery criteria # 2 due to their inherently small population sizes and marginal habitat quality. Due to the cyclic nature of running buffalo clover and the high probability of small populations blinking in and out, maintaining viability for a specific Cranked or D-ranked population at a given time may not be possible. Regardless, small populations have displayed high levels of genetic diversity that is important for survival of the species as a whole and thus are included in the recovery criteria referring to protection and management of sites.

Go here to view the complete 77-page Running Buffalo Clover Revised Recovery Plan (PDF).

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