The goal of the project is to improve and expand areas occupied by the San Diego thornmint (MSP Category SO [Significant occurrence(s) at risk of loss from MSPA]) within Mission Trails Regional Park (MTRP) Fortuna through restoration and enhancement of degraded habitat. This program addresses the immediate needs of thornmint within the MTRP by building on the on-going City weed treatment effort (based on SANDAG-funded CBI protocols to address Brachypodium distachyon) to address loss and degradation of existing thornmint habitat due to an increase of invasive plants and drought. Activities included in this program consist of herbicide treatment, thornmint and other native seed collection, seed bulking and redistribution, vegetation monitoring, photo monitoring, and thornmint monitoring. The methodologies used in conjunction with this proposal are similar to those used to restore approximately .25 acres of Pogogyne nudiuscula (Otay Mesa Mint) vernal pool habitat located in Otay Mesa. This project is consistent with the management objectives and actions prescribed in CBl's / SDMMP's Adaptive Management Framework for the Endangered San Diego Thornmint, the MTRP Natural Resources Management Plan, and the City of San Diego MHPA - Eastern Area MSCP Subarea Plan. Herbicide weed treatment within the thornmint population at MTRP Fortuna last occurred in 2014 and 2015.
San Diego thorn-mint
San Diego Association of Governments
Mission Trails Regional Park Foundation, Inc.
San Diego thorn-mint Acanthomintha ilicifolia
Goal: Maintain large populations, enhance small populations, and establish new populations of San Diego thornmint or pollinator habitat to buffer against environmental stochasticity, maintain genetic diversity, and promote connectivity, thereby enhancing resilience within and among MUs over the long-term (>100 years) in native habitats.
Beginning in 2017, conduct routine management actions identified through the IMG monitoring at San Diego thornmint occurrences on Conserved Lands (see occurrence table). Depending on the type and level of threat, management should only be conducted as needed, not necessarily every year, and using BMPs with precautions to do no harm.
Perform routine management activities as needed, such as protecting occurrences from disturbance through enforcement and controlling invasive non-native plant species to =20% absolute cover.
Beginning in 2017, annually inspect conserved populations of San Diego thornmint (see occurrence table) using the regional rare plant IMG monitoring protocol to record abundance and collect covariate habitat and threats data to determine management needs.
In 2017, continue refining BMPs developed for San Diego thornmint (CBI 2014) by incorporating results of management experiments to control invasive species that threaten populations (e.g., Brachypodium removal studies at Mission Trails and South Crest) and based on research studies (e.g., seed bulking guidelines, seed transfer zones).
In 2018, begin preparing a section for San Diego thornmint the MSP Rare Plant Management Plan that prioritizes management actions to maintain or expand occurrences on Conserved Lands based upon an assessment of data on occurrence status, habitat and threats. Prioritize management recommendations to maintain large occurrences and enhance at least 3 small occurrences (see occurrence table). Minimum criteria for enhancement are to reduce invasive annual nonnative plants and thatch to less than 20% absolute cover within the occurrence
In 2018, begin preparing a section for San Diego thornmint in the MSP Seed Collection, Banking and Bulking Plan to preserve genetic diversity and rescue occurrences in case of catastrophic disturbance. The plan should incorporate best science and management practices (Wall 2009, KEW 2016) and recommendations from the 2016-2017 genetic study to provide guidelines for collecting and storing seeds over the long term at a permanent, established conservation seed bank (e.g., Institute for Conservation Research Native Plant Seed Bank, Rancho Santa Ana Botanic Garden Seed Conservation Program) and for providing sources of seeds for management purposes. The plan should include recommendations for: collecting and storing seeds for conservation banking; management oriented research; rescuing occurrences after catastrophic disturbances; and seed bulking and out-planting to augment extant occurrences or to establish new occurrences with consideration of genetic implications for population sustainability.