Point Reyes bird's beak: Population monitoring and disturbance evaluation

Cordylanthus maritimus ssp. palustris (Point Reyes bird's beak) 

Point Reyes bird’s beak (Cordylanthus maritimus ssp. palustris) is a unique hemiparasitic halophite native to salt marshes on the coasts of Oregon and California.  It is only found in tidal salt marshes, leaving many of the populations exposed to the threats of filling, tidal manipulation, and water pollution.  The US Fish and Wildlife Service lists this species as a Species of Concern and the Oregon Department of Agriculture considers it to be Endangered.  There are 18 known occurrences of Point Reyes bird's beak within the state of Oregon, with the colonies’ populations averaging 2,000 individuals.  The population that is currently monitored by the Institute for Applied Ecology (IAE) is located on the North Spit of Coos Bay within a BLM Area of Critical Environmental Concern (ACEC).  Monitoring began in 2010 and has continued annually in an effort to track changes in population size and location.  IAE also collects plant community data to analyze Point Reyes bird's beak's preferred habitat.

Point Reyes bird’s beak is an annual that blooms June through September and produces fruits August through November.   This species reproduces from seed, but requires very specific levels of salinity in the marsh in order for the seeds to germinate.  There is some evidence indicating that Point Reyes bird’s beak is a self-pollinator, unlike similar species which require pollinators.  This plant is a member of the Orobancaceae family, which consists of holoparasitic and hemiparasitic plant species.  Hemiparasitic plants, such as Point Reyes bird’s beak, can produce some of their own energy through photosynthesis, but also utilize underground root connections to derive resources from neighboring plants.  While this particular species lacks host specificity, it is commonly found in association with Virginia glasswort (Salicornia depressa), marsh rosemary (Limonium californicum) and marsh jaumea (Jaumea carnosa).

IAE crew members (L to R: Erin, Eddie, Charlotte, Guy) monitoring community composition and population density along transect.

In recent years, the BLM took action to protect a portion of the North Spit population by diverting an access road around the largest grouping of plants.  In the first several years of monitoring on the North Spit, the primary research objectives were mapping population size and testing the effects of interspecific competition between Point Reyes bird’s beak and its associated species.  After it was determined that there was no competition effect presented by surrounding species, research shifted to focusing on population mapping and, starting in 2012, comparing population size and success of protected versus unprotected areas.  Ten transects within the protected area were monitored in order to collect data on community composition and species density.  Data on the density of Point Reyes bird’s beak, the associated plant community, and habitat type were recorded within each meter sampled, and were used to estimate the number of individuals present within the entire population.  This year, four new transects were established within the unprotected portion of the population to provide a functional comparison of the effects of human disturbance (e.g. ORV use). 

ORV tracks through the C. maritimus population

The primary threat to this specific population continues to be human disturbance, but additional threats include water pollution.  Individual populations can be affected by changes in microtopography of the marshes due to sand accretion, changing tidal patterns, or recreational and industrial uses in close proximity to the habitat. Continued monitoring of the population size and habitat will provide information about how the North Spit population responds to disturbance pressures and can be used to inform future decisions about management and protection. 

Population monitoring of Cusick's lupine in Baker County, Oregon

Cusick's lupine inflorescence

Lupinus lepidus var. cusickii (Cusick’s lupine) is a narrow endemic forb inhabiting eroding volcanic ash deposits in eastern Oregon’s Baker County.  Given its extremely limited geographic distribution, the Oregon Department of Agriculture has listed it as a state endangered species.  The BLM considers it to be a special status species, meaning that management actions must be taken in order to avoid having the plant listed as threatened or endangered on the federal level.  All populations fall within the Blue Mountains physiographic region, part of the Columbia Plateau geologic formation.

Herbarium specimen collected

Cusick’s lupine was originally discovered in 1886, but very little information existed about its range and population extent.  Over the past several decades, field surveys have been conducted using the Intuitive Controlled survey method to determine where populations currently exist.  Potential habitat was first identified by analyzing aerial photos and topographic maps. To date, there are five small populations of Cusick’s lupine found on BLM land in Baker County.  Although the plant was uncommon throughout the survey area, locations that did contain Cusick’s lupine were fairly densely populated.  The known populations were found on eroding hillsides where competition from other plants species was low.  Surveys will continue to be conducted throughout areas of interest to provide accurate information about the full extent of the population and to help prioritize management actions.

BLM Botanist, Roger Ferriel, assisting IAE crew

Cusick’s lupine is a low-lying perennial, often found growing in dense clusters. Short purple and white racemes, which flower in July, are generally surpassed by the plant’s foliage.  Stems are branched at the base and leaves are mainly basal.  There are four other varieties of Lupinus lepidus occurring in eastern Oregon, but variety cusickii can be distinguished by its low raceme position, short stature (up to 11 cm tall), and erect growth.  Seed production is vital for population maintenance since Cusick’s lupine does not reproduce vegetatively.

Population monitoring on permanent transects began in 1993 and has continued to occur intermittently.  Fences were erected at three populations to exclude human disturbance from portions of the population.  This season, Vale District BLM Botanist Roger Ferriel joined the IAE crew to assist at several monitoring sites.  At each monitoring location, data was recorded regarding plant height, diameter and perpendicular width, the number of inflorescences and evidence of herbivory.  Population density and plant health have varied considerably over the years, most likely due to climatic variation.  Threats to the Cusick’s lupine populations include small population size, invasive species, and human disturbance (off-road vehicle use and illegal dumping).  Although the populations do not appear to be in immediate danger, continued disturbance by humans could potentially degrade the limited habitat available to this lupine species.  Since little information exists about cultivation of this species, seeds were collected from three populations to be used in future germination trials. A subset of these seeds will be sent to the Rae Selling Berry Seed Bank to be stored in case reintroduction projects are needed to mitigate unforeseen anthropogenic or natural population disturbances.

Cusick's lupine habitat (foreground) at ORV Hill monitoring site

Population dynamics of Mulford's milkvetch

Population monitoring at the South Alkali population. Vale, Oregon

Although Oregon is well known for its coniferous forests, low valley prairies, and coastline that receive high amounts of rainfall, nearly two thirds of the state exhibits semi-arid habitat conditions.  Oregon’s eastern desert region experiences greater seasonal fluctuation than the western portion of the state and is inhabited by plants and animals that can tolerate extreme differences in weather.  The high desert receives significant amounts of snow in the winter, but quickly dries out in the spring.  The characteristic plant community in eastern Oregon consists of juniper and sagebrush scrublands with bunchgrasses such as needle-and-thread grass (Hesperostipa comata) and Indian rice grass (Achnatherum hymenoides).

Astragalus mulfordiae (Mulford’s milkvetch), listed as a Species of Concern by the US Fish and Wildlife Service, is a member of the legume family (Fabaceae) native to the Snake River Plain of Oregon and Idaho.  In 1995, only 38 populations of Mulford’s milkvetch were known to occur in Oregon, in addition to 34 populations in Idaho.   It was estimated that, in total, there were less than 12,000 living individuals.  Mulford's milkvetch only occurs in desert shrub communities on sandy substrates, such as lacustrine and alluvial sediments.  The plant relies on environmental cues to initiate regrowth, but it can generally be seen flowering between April and June.  Flowers are yellowish to white in color and measure 6-8 mm in length.  Fruits usually mature in June and July.      

Astragalus mulfordiae

IAE has tracked Mulford's milkvetch populations in the BLM’s Vale district since 2008, beginning with the establishment of monitoring plots to determine the effects of ungulate and rodent grazing on the populations.  Large animal exclosures and unfenced control plots were established at five different sites around Vale, Oregon.  In the second year of monitoring, transects were established in order to collect data on the plant community associated with Mulford’s milkvetch.   The monitoring protocol used by IAE is consistent with the methods being used to monitor the populations in Idaho, allowing for comparable data sets.  During annual monitoring, data regarding plant life history stage (reproductive, non-reproductive, seedling) and evidence of herbivory and disturbance were documented, as well as quantitative data on plant size and number of inflorescences (flowering stems).  Population trends were difficult to discern after the first few years of monitoring, but continued monitoring may provide more information about the effects of mammal grazing on the size and health of the Mulford's milkvetch populations.  Currently, there appears to be high turnover of individual plants.  The community sampling transects have revealed ubiquitous invasive and non-native plants that could potentially compete with the native milkvetch.  IAE will continue to monitor these populations to increase understanding of population dynamics for this rare species, and to analyze the potential threats of cattle grazing, rodent activity, encroachment of invasives, and ground disturbance.

Evidence of cattle activity adjacent to mammal exclosure