Assessment of Willowy Monardella (Monardella viminea) Status, Habitat, and Threats on Conserved Lands in San Diego County

The updated Framework Rare Plant Management Plan for
Conserved Lands in Western San Diego County (FRPMP) released in 2021 included a species-specific management plan for willowy monardella that recommended a framework for managing known populations and suggested the
following information needs: 1) Identify sites where willowy monardella has been extirpated but
would be suitable for reintroduction, 2) Identify locations that contain suitable habitat for willowy
monardella to be introduced into, and 3) Develop hydrology models based on analysis of
locations where monardella exists to identify which areas of suitable habitat have hydrology
most conducive to the establishment and survival of willowy monardella.
The FRPMP recommendations include the field collection of data regarding the physical and
biotic characteristics, hydrology, and levels of disturbance in existing populations of willowy
monardella and ground-level assessment of other locations that may support the same
characteristics as the known locations. This project addresses these recommendations.
The goal of these assessments is to identify potential receptor sites for establishment of new
willowy monardella populations or locations of historical populations suitable for reintroduction of
willowy monardella. The assessment also evaluated management needs within these suitable
receptor locations as well as existing, occupied drainages. Receptor sites and management actions were identified through the collection of data about the physical and biotic
characteristics, hydrology, and levels of disturbance.

Monitoring-Plants
Rare Plants
completed
Project Focus

Willowy monardella

Emily Perkins

San Diego Association of Governments

AECOM

San Diego Management and Monitoring Program

Kris Preston

Sarah McCutcheon

Kris Preston

Willowy monardella Monardella viminea

Goal: Maintain or enhance existing willowy monardella occurrences and establish new occurrences, as needed, to ensure multiple conserved occurrences with self sustaining populations to increase resilience to environmental and demographic stochasticity, maintain genetic diversity, and ensure persistence over the long term (>100 years) in coastal sage scrub vegetation communities.

regional NFO 2020 SL
MGT-PRP-MGTPL MONVIM-7

Management units: 4, 6

In 2020, begin preparing a section for willowy monardella in the MSP Rare Plant Management Plan that prioritizes management actions to maintain the large occurrence and enhance at least 4 small occurrences on Conserved Lands (see occurrence table) based upon an assessment of data on occurrence status, habitat and threats. Prepare prioritized management recommendations to re-establish historic occurrences or new occurrences in suitable habitat, if determined to be necessary for gene flow and to maintain self sustaining populations for the long term persistence of the species in the MSPA. Minimum criteria for enhancement are to reduce invasive annual nonnative plants and thatch to less than 20% absolute cover within the occurrence.

Action Statement Action status Projects
PRP-1 Consult the San Diego County Rare Plant Working Group made up of plant ecologists, geneticists, rare plant experts, land managers, restoration practitioners, seed banking and bulking practitioners, wildlife agencies, MCAS Miramar, and other stakeholders to provide input and recommendations for the willowy monardella section in the MSP Rare Plant Management Plan. waiting for precedent action
PRP-2 Develop a conceptual model that identifies management actions to effectively reduce threats to willowy monardella occurrences. waiting for precedent action Assessment of Willowy Monardella (Monardella viminea) Status, Habitat, and Threats on Conserved Lands in San Diego County
PRP-3 Prioritize occurrences for management based upon an assessment of occurrence status, the potential for management to significantly reduce identified threats, and the availability of adjacent suitable habitat for occurrence expansion. waiting for precedent action
PRP-4 Develop an implementation plan for willowy monardella that prioritizes management actions for the next 5 years and details tasks, lead entities, responsibilities, and timelines, budgets. waiting for precedent action Assessment of Willowy Monardella (Monardella viminea) Status, Habitat, and Threats on Conserved Lands in San Diego County
PRP-5 Submit project metadata and MSP Rare Plant Management Plan to the MSP Web Portal. waiting for precedent action Assessment of Willowy Monardella (Monardella viminea) Status, Habitat, and Threats on Conserved Lands in San Diego County
Criteria Deadline year
By 2020, Completed Willowy Monardella Section in MSP Rare Plant Management Plan 2021
Threat Name Threat Code
Altered fire regimeALTFIR
Altered hydrologyALTHYD
Climate changeCLICHN
Human uses of the PreservesHUMUSE
Invasive plantsINVPLA
Urban developmentURBDEV
Code Obj. code Statement
MONVIM-1 MON-IMP-IMG From 2017-2021, inspect willowy monardella occurrences annually on Conserved Lands (see occurrence table) using the regional rare plant IMG monitoring protocol to record abundance and collect habitat and threats covariate data to determine management needs.
MONVIM-2 MGT-IMP-IMG Beginning in 2017, conduct routine management actions identified through the annual IMG monitoring at willowy monardella occurrences on Conserved Lands (see occurrence table). Depending on the type and level of threat, management should be conducted as needed, not necessarily every year, and using BMPs with precautions to do no harm.
MONVIM-3 MON-RES-GEN In 2017, complete the study begun in 2016 to characterize the population genetic structure, gene flow, and genetic diversity for willowy monardella occurrences (see occurrence table). The study will determine if there is evidence of mixed ploidy levels within or among occurrences; evaluate vulnerability of occurrences to genetic drift and loss of genetic diversity; assess the level of gene flow among occurrences; identify if there are signatures of genetic bottlenecks or low genetic diversity in occurrences that have undergone recent reductions; and look for evidence of local population adaptation. Based on the results of the genetic analyses, management recommendations will include whether common garden and reciprocal transplantations are necessary before proceeding with population enhancement or restoration and will provide specific recommendations for collecting and redistributing or bulking seed to enhance existing occurrences or establish new occurrences.
MONVIM-4 MON-SURV-SPEC In 2019, survey historic willowy monardella locations to determine occurrence status; survey and delineate potentially suitable habitat for new occurrences; survey existing occurrences to identify the potential for enhancement and expansion; and at all sites collect data on occurrence status, habitat and threats and determine management needs. Conduct a hydrological evaluation at each site to determine the current hydrology and risk to existing or potential occurrences from erosion and flooding. Prioritize all evaluated sites based on feasibility of maintaining a sustainable population over the long term and recommend management needed to reduce threats to existing and potential new occurrences.
MONVIM-5 MGT-PRP-SBPL In 2020, begin preparing a section for willowy monardella in the MSP Seed Collection, Banking and Bulking Plan that incorporates best science and management practices (Wall 2009, KEW 2016) to preserve genetic diversity and rescue occurrences in case of catastrophic disturbance. The plan should also include recommendations from the 2016-2017 genetic study and the 2019 baseline surveys and hydrological evaluation to guide collection and storage of 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 a source 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.
MONVIM-6 MGT-IMP-SBPL In 2021, begin implementing high priority actions for willowy monardella in the MSP Seed Collection, Banking and Bulking Plan to collect and store seeds at a permanent seed bank and to provide propagules as needed for management oriented research, existing population enhancement and establishment of new occurrences.
MONVIM-8 MGT-IMP-MGTPL In 2021, begin implementing highest priority management actions identified for willowy monardella in the MSP Rare Plant Management Plan.
MONVIM-9 MON-IMP-MGTPL In 2021, monitor effectiveness of implementation of highest priority management actions identified in the willowy monardella section in the MSP Rare Plant Management Plan.
MONVIM-10 MGT-MON-FMGT Beginning in 2018, conduct a post fire evaluation of hydrological processes at willowy monardella occurrences following a fire to determine risks from erosion and flooding and prepare a report with prioritized management recommendations to reduce risk to population persistence and sustainability.

Willowy monardella Monardella viminea

Goal: Maintain or enhance existing willowy monardella occurrences and establish new occurrences, as needed, to ensure multiple conserved occurrences with self sustaining populations to increase resilience to environmental and demographic stochasticity, maintain genetic diversity, and ensure persistence over the long term (>100 years) in coastal sage scrub vegetation communities.

regional and/or local NFO 2021 SL
MGT-IMP-MGTPL MONVIM-8

Management units: 4, 6

In 2021, begin implementing highest priority management actions identified for willowy monardella in the MSP Rare Plant Management Plan.

Action Statement Action status Projects
IMP-1 Submit metadata, management datasets, and report to the MSP Web Portal. waiting for precedent action Assessment of Willowy Monardella (Monardella viminea) Status, Habitat, and Threats on Conserved Lands in San Diego County
Criteria Deadline year
By 2024, =2 High Priority Management Action Implemented for Willowy Monardella from the MSP Rare Plant Management Plan 2021
Threat Name Threat Code
Altered fire regimeALTFIR
Altered hydrologyALTHYD
Climate changeCLICHN
Human uses of the PreservesHUMUSE
Invasive plantsINVPLA
Urban developmentURBDEV
Code Obj. code Statement
MONVIM-6 MGT-IMP-SBPL In 2021, begin implementing high priority actions for willowy monardella in the MSP Seed Collection, Banking and Bulking Plan to collect and store seeds at a permanent seed bank and to provide propagules as needed for management oriented research, existing population enhancement and establishment of new occurrences.
MONVIM-7 MGT-PRP-MGTPL In 2020, begin preparing a section for willowy monardella in the MSP Rare Plant Management Plan that prioritizes management actions to maintain the large occurrence and enhance at least 4 small occurrences on Conserved Lands (see occurrence table) based upon an assessment of data on occurrence status, habitat and threats. Prepare prioritized management recommendations to re-establish historic occurrences or new occurrences in suitable habitat, if determined to be necessary for gene flow and to maintain self sustaining populations for the long term persistence of the species in the MSPA. Minimum criteria for enhancement are to reduce invasive annual nonnative plants and thatch to less than 20% absolute cover within the occurrence.
MONVIM-9 MON-IMP-MGTPL In 2021, monitor effectiveness of implementation of highest priority management actions identified in the willowy monardella section in the MSP Rare Plant Management Plan.

Willowy monardella Monardella viminea

Goal: Maintain or enhance existing willowy monardella occurrences and establish new occurrences, as needed, to ensure multiple conserved occurrences with self sustaining populations to increase resilience to environmental and demographic stochasticity, maintain genetic diversity, and ensure persistence over the long term (>100 years) in coastal sage scrub vegetation communities.

regional NFO 2019 SL
MON-SURV-SPEC MONVIM-4

Management units: 4, 6

In 2019, survey historic willowy monardella locations to determine occurrence status; survey and delineate potentially suitable habitat for new occurrences; survey existing occurrences to identify the potential for enhancement and expansion; and at all sites collect data on occurrence status, habitat and threats and determine management needs. Conduct a hydrological evaluation at each site to determine the current hydrology and risk to existing or potential occurrences from erosion and flooding. Prioritize all evaluated sites based on feasibility of maintaining a sustainable population over the long term and recommend management needed to reduce threats to existing and potential new occurrences.

Action Statement Action status Projects
SURV-1 At each extant occurrence, map the extent of the occurrence, collect data on abundance, map adjacent suitable habitat for potential occurrence expansion, collect covariate data on threats including estimates of cover of invasive non-native plants and trampling. on hold
SURV-2 Submit project metadata, habitat mapping, and a report with site prioritizations and recommendations for management based upon occurrence status, habitat and threats assessments and hydrological evaluations to the MSP Web Portal. on hold Assessment of Willowy Monardella (Monardella viminea) Status, Habitat, and Threats on Conserved Lands in San Diego County
Criteria Deadline year
Surveys and Report Completed by 2019 2021
Threat Name Threat Code
Altered fire regimeALTFIR
Altered hydrologyALTHYD
Human uses of the PreservesHUMUSE
Invasive plantsINVPLA
Urban developmentURBDEV
Code Obj. code Statement
MONVIM-1 MON-IMP-IMG From 2017-2021, inspect willowy monardella occurrences annually on Conserved Lands (see occurrence table) using the regional rare plant IMG monitoring protocol to record abundance and collect habitat and threats covariate data to determine management needs.
MONVIM-7 MGT-PRP-MGTPL In 2020, begin preparing a section for willowy monardella in the MSP Rare Plant Management Plan that prioritizes management actions to maintain the large occurrence and enhance at least 4 small occurrences on Conserved Lands (see occurrence table) based upon an assessment of data on occurrence status, habitat and threats. Prepare prioritized management recommendations to re-establish historic occurrences or new occurrences in suitable habitat, if determined to be necessary for gene flow and to maintain self sustaining populations for the long term persistence of the species in the MSPA. Minimum criteria for enhancement are to reduce invasive annual nonnative plants and thatch to less than 20% absolute cover within the occurrence.
MONVIM-10 MGT-MON-FMGT Beginning in 2018, conduct a post fire evaluation of hydrological processes at willowy monardella occurrences following a fire to determine risks from erosion and flooding and prepare a report with prioritized management recommendations to reduce risk to population persistence and sustainability.
File name Lead Author Year Type
Assessment of Willowy Monardella Status, Habitat, and Threats on Conserved Lands in San Diego County Maunsell, Ian; Brand Ramirez, Diana 2022 powerpoint presentation
Assessment of Willowy Monardella (Monardella viminea) Status, Habitat, and Threats on Conserved Lands in San Diego County AECOM 2022 report
Recording - September 2022 SDMMP Management and Monitoring Coordination Meeting Brand Ramirez, Diana; Maunsell, Ian; Perkins, Emily; Baldridge, Ann; Bacay, Ashleyann; Guia, Carolina 2022 recording
Project Files
File name
MOVI_Original_Public.gdb.zip