Preserve Selection and Design Considerations: The 2.5 square miles of the four watersheds feeding the lakes deserve special consideration. Crucial habitat should be defined as an entire lake up to the highest water line as the distribution of P. WILLIAMSIAE appears to follow a widely fluctuating water table. If trampling becomes a concern, a crescent shape exclosure around the most dense area of the population would add a measure of protection and allow livestock access to water.
Management Requirements: Three of the lakes are located on BLM land within section 16 of Township 17 N, Range 20 E. A checkerboard ownership pattern has put the eastern most lake on private land within section 15 belonging to: Gloria Laborde, Overhill Lane, Davis, CA. 95616. Section 16 is part of the 15,389 acre Jumbo grazing allotment managed under the BLM Carson City District. Gloria Laborde also owns section 21 which lies south of section 16 and includes the principal road accessing the area, and part of the main drainage that feeds the largest lake.
Monitoring Programs: On the Jumbo allotment BLM monitoring studies in the lakes basin have typically focused on three key forage plant species, SITANION HYSTRIX, ORYZOPSIS HYMENOIDES, and STIPA THURBERIANA. These key plant species are the most important forage species on this part of the allotment and provide the bulk of the forage (Raffetto 1992). Range utilization is measured yearly on these key species and use pattern maps made to determine if use is too heavy or light to meet management objectives (Handbook 1984).
Actual use reports are written yearly by the allotment operators and reflect general livestock use patterns and range condition.
Two permanent sagebrush-grass photo plots were established in the allotment in 1968. A vertical view of a 3'X3'plot and an oblique view of the plot and surrounding vegetation were taken every 3-5 years. The technique was discontinued several years ago due to it's ineffectiveness to accurately monitor vegetation change (Raffetto 1992).
Biological Research Needs: Biosystematic studies are needed to ensure the status of P. WILLIAMSIAE as a unique genetic and morphological entity deserving protection and legal recognition.
Habitat requirements need to be studied. What is P. WILLIAMSIAE'S ecological and physiological optimum? Where is it establishing itself and where is it dying? Is it typically associated with severely disturbed areas opened up for invasion by cattle or sheep?. What are its tolerance ranges to sheep and cattle grazing, salt, and flooding? How extensive is P. WILLIAMSIAE'S seed bank in the lakes basin and what are its seed dormancy requirements? How are watershed hydrology dynamics and plant distribution related; most importantly, what is the climatic history of the area?
Life history characteristics are limited to generalities that P. WILLIAMSIAE is an herbaceous perennial. Details should be known on seed production and viability, conditions promoting germination, habitat requirements for seedling establishment, seral stage preferences, survivorship patterns, phenology, growth rates, pollinators, and seed dispersal vectors.
POLYCTENIUM WILLIAMSIAE is considered to be one of the rarest and most endangered species in Nevada because of its small population size, narrow geographical distribution, proximity to an urban area, and high disturbance potential (Tiehm 1992). The smaller the population, the more likely extinction is in any given period of time (Shaffer 1987). Therefore, knowledge of minimum viable population size and its area requirements would be valuable. How much larger than minimum viable size is best for effective management?
Can POLYCTENIUM FREMONTII be used as an appropriate model for P. WILLIAMSIAE in manipulative physiological studies, where large numbers of plants may have to be sacrificed?
Future inventory efforts should concentrate on nearby topographic features with similar geologic and hydrologic characteristics. Areas where negative searches were conducted (Knight 1990) should be resurveyed.