Cascade Head Catchfly (Silene douglasii var. oraria)

After introducing a total of >1800 seeds, the Willamette University compared experimentally manipulated and natural populations of widespread Silene douglasii var. douglasii relative to rare S. douglasii var. oraria, known in only three coastal headlands of Oregon. Despite equivalent ex situ germination, oraria field plots produced significantly fewer juveniles than douglasii plots indicating that seedling survival limits plant establishment. We also evaluated transplant vs. seed reintroductions as restoration tools, the effect of inbreeding on fitness, and the potential importance of buried seed pools. Germination declined rapidly for seeds over 1-2 years old, and only 2.2% of newly collected seeds of oraria survived as seedlings. Transplant survival over 3 years was greatest for outbred proginy, furthermore 75% of the new seedlings emerged near outbred progeny from original reintroduction. Despite similar ovule numbers and pollinator visitation, transplants exhibited 49-179% maladaptation in the formerly grazed site, with significantly lower fruit and seed set than adults in more diverse natural populations. This study experimentally identified several key factors affecting reintroduction, facilitating effective development of large-scale reintroduction strategies for native plants.

After introducing a total of >1800 seeds, the Willamette University compared experimentally manipulated and natural populations of widespread Silene douglasii var. douglasii relative to rare S. douglasii var. oraria, known in only three coastal headlands of Oregon. Despite equivalent ex situ germination, oraria field plots produced significantly fewer juveniles than douglasii plots indicating that seedling survival limits plant establishment. We also evaluated transplant vs. seed reintroductions as restoration tools, the effect of inbreeding on fitness, and the potential importance of buried seed pools. Germination declined rapidly for seeds over 1-2 years old, and only 2.2% of newly collected seeds of oraria survived as seedlings. Transplant survival over 3 years was greatest for outbred proginy, furthermore 75% of the new seedlings emerged near outbred progeny from original reintroduction. Despite similar ovule numbers and pollinator visitation, transplants exhibited 49-179% maladaptation in the formerly grazed site, with significantly lower fruit and seed set than adults in more diverse natural populations. This study experimentally identified several key factors affecting reintroduction, facilitating effective development of large-scale reintroduction strategies for native plants.

Genetic studies using microsatellite DNA are currently underway (Kephart and Yee, unpublished in: Kephart et al. 1999).

Germination trials at The Berry Botanic Garden indicate that this species germinates readily under a variety of conditions but that it does slightly better when subjected to cold stratification and constant temperatures. 100% of seeds germinated when subjected to 8 weeks of cold stratification followed by constant 68F (20C) and 80% germinated when cold stratification was followed by alternating 50F/68F (10/20C) temperatures. Without cold stratification, 80% of seeds germinated in the constant temperature treatment and 60% germinated under the alternating temperature treatment (BBG File).

Studies to determine the mating system and to quantify the magnitude of inbreeding depression were conducted. Flower treatments included emasculation (removal of pollen) followed by treatment with the plant's own pollen (self) or another plant's pollen (outcross), bagging (exclusion of pollinators), and open pollination. Silene douglasii var. oraria has a mixed mating system. It is capable of setting seed with its own pollen or pollen from another plant. Inbreeding depression was high compared to many outcrossing species (Kephart et al. 1999). Studies of the pollination biology of Silene douglasii var. oraria. Natural pollen deposition was monitored. Fruit production, seed number and weight, and progeny vigor were studied for different pollination treatments (selfed, open pollinated, and different amounts of supplemental pollen). Overall, it appears that most natural pollen transfer involves self-pollination and low reproductive success reflects low pollen quantity and quality (Brown and Kephart 1999).

Long term (10 year) demographic monitoring of Silene douglasii var. oraria in two habitat types (grassy and rocky) at one site to aid in determining long-term population trends and habitat preferences. At the conclusion of the study, population growth appeared stable in the rocky sites and slightly declining in the grassy. Plants growing in the grassy habitat were more sparse but larger than plants growing in the rocky habitat. There was more seedling recruitment and adult survivorship in the open, rocky sites (Kephart and Paladino 1997). The three varieties of Silene douglasii (var. oraria, var. douglasii, and var. rupinae) were compared using a wide variety of morphological characteristics. Significant differences among varieties were found, reinforcing the categorization of the three varieties. Significant differences were also found within each of the three varieties, indicating geographic differences and population substructuring (Kephart et al. 1999).

Re-introduction of more than 200 individuals grown in the greenhouse into formerly grazed habitat (in Brown and Kephart 1999).

Seeds from two occurrences are currently stored at The Berry Botanic Garden.

Seeds from two occurrences are currently stored at The Berry Botanic Garden.

Extremely low numbers of individuals and populations. Habitat and range extremely restricted. Threatened by hikers and potentially climate change.

Heavy recreational use (Meinke 1982). Competition from aggressive, weedy species (Meinke 1982). Coastal development and deforestation leading to habitat degradation and fragmentation (Brown and Kephart 1999). Habitat fragmentation leading to reduce

3 known populations. The largest contains over 1000 individuals. The other two sites contain fewer than 100 individuals (Brown and Kephart 1999).

Long term (10 year) demographic monitoring of Silene douglasii var. oraria in two habitat types (grassy and rocky) at one site to aid in determining long-term population trends and habitat preferences. At the conclusion of the study, population growth appeared stable in the rocky sites and slightly declining in the grassy. Plants growing in the grassy habitat were more sparse but larger than plants growing in the rocky habitat. There was more seedling recruitment and adult survivorship in the open, rocky sites (Kephart and Paladino 1997). The three varieties of Silene douglasii (var. oraria, var. douglasii, and var. rupinae) were compared using a wide variety of morphological characteristics. Significant differences among varieties were found, reinforcing the categorization of the three varieties. Significant differences were also found within each of the three varieties, indicating geographic differences and population substructuring (Kephart et al. 1999). Studies to determine the mating system and to quantify the magnitude of inbreeding depression were conducted. Flower treatments included emasculation (removal of pollen) followed by treatment with the plant's own pollen (self) or another plant's pollen (outcross), bagging (exclusion of pollinators), and open pollination. Silene douglasii var. oraria has a mixed mating system. It is capable of setting seed with its own pollen or pollen from another plant. Inbreeding depression was high compared to many outcrossing species (Kephart et al. 1999). Studies of the pollination biology of Silene douglasii var. oraria. Natural pollen deposition was monitored. Fruit production, seed number and weight, and progeny vigor were studied for different pollination treatments (selfed, open pollinated, and different amounts of supplemental pollen). Overall, it appears that most natural pollen transfer involves self-pollination and low reproductive success reflects low pollen quantity and quality (Brown and Kephart 1999). Germination trials at The Berry Botanic Garden indicate that this species germinates readily under a variety of conditions but that it does slightly better when subjected to cold stratification and constant temperatures. 100% of seeds germinated when subjected to 8 weeks of cold stratification followed by constant 68F (20C) and 80% germinated when cold stratification was followed by alternating 50F/68F (10/20C) temperatures. Without cold stratification, 80% of seeds germinated in the constant temperature treatment and 60% germinated under the alternating temperature treatment (BBG File). Genetic studies using microsatellite DNA are currently underway (Kephart and Yee, unpublished in: Kephart et al. 1999).

Seeds from two occurrences are currently stored at The Berry Botanic Garden. The largest known population is on private land that is managed by The Nature Conservancy. The two other known populations are on State Park land. This species is listed as threatened by the state of Oregon, so plants on state land are protected from destruction and development. Re-introduction of more than 200 individuals grown in the greenhouse into formerly grazed habitat (in Brown and Kephart 1999).

Fence plants to limit herbivory and trampling. This will help maintain adequate numbers of flowering plants to help reduce inbreeding depression (Brown and Kephart 1999). Minimize the encroachment of shrubs (Kephart and Paladino 1997). Develop an effective method of reducing litter accumulation and other cover in grassy habitats (Kephart and Paladino 1997).

Collect and store seeds from all known populations. Determine propagation and reintroduction protocols.