Ecological and evolutionary factors affecting threatened and endangered species may compromise a population’s ability to persist through time. Here, I determined how plant mating system, pollination biology, pollen source, habitat type, and white-tailed deer (Odocoileus virginianus) herbivory affected the persistence of a rare wetland endemic plant, Polemonium vanbruntiae (Eastern Jacob’s ladder). In contrast to several of the more common species of Polemonium, I found no pollen limitation in populations of P. vanbruntiae. The lack of pollen limitation was best explained by the capacity for P. vanbruntiae to self-fertilize. However, pollinators play an important role as inter- and intra-plant pollen vectors in this system because female reproductive fitness was greatly reduced when pollinators were excluded. These results support the reproductive assurance hypothesis, whereby the ability to self assures fertilization for plants in small populations. A mixed-mating strategy, including the ability for clonal reproduction, may explain the ability for this rare species to persist in small, fragmented populations. However, mixed mating strategies may incur both costs and benefits. The ability to self-fertilize may provide reproductive assurance that when pollinators and/or potential mates are scarce. Yet, selfing is potentially costly when the result is a reduction in offspring quantity and quality. I found that the relative performance of selfed offspring was lower than outcross offspring in terms of germination and offspring vigor. When pollen is received from a distant site, offspring exhibit heterosis with increased vigor in terms of more leaves, larger leaf area and height. Although I was unable to follow offspring survival to flowering, enhanced germination success and more vigorous growth suggest that gene flow among populations may increase plant vigor and enhance genetic variation within small, isolated populations of P. vanbruntiae. For long-lived organisms such as perennial plants, it is often difficult to determine which environmental factors will have the largest effects on long-term population dynamics. I incorporated the effects of habitat type and white-tailed deer herbivory into a population viability model for P. vanbruntiae to determine the effects of both habitat and herbivory on long-term ramet dynamics. Polemonium vanbruntiae ramets in wet meadow habitats are expected to increase at a faster rate than ramets in the forest seep habitats, but P. vanbruntiae is expected to increase over time in both habitat conditions. White-tailed deer preferentially browsed adult ramets, primarily those occurring in forest seep sites. Deer browsing significantly decreased the predicted population growth rate under stochastic conditions, although P. vanbruntiae ramets are expected to increase at a slow rate in the future under herbivore pressure. Herbivory also increased the extinction risk to a detectable level. Deer browsing shifted the potential for younger life histories stages to change future population growth. Instead, survival and stasis of large vegetative ramets became the vital rates having the largest potential impact on future population growth. Thus, active long-term management of deer populations appears necessary for the guaranteed persistence of populations of rare, endemic herbs such as P. vanbruntiae.

Taxonomic delimitation of rare species is vital for accurate assessments of diversity and for their conservation. Cycladenia humilis, the sole species of Cycladenia, is an enigmatic perennial widely dispersed across the western United States. Within this species there are three currently recognized varieties: C. humilis var. humilis in Northern California, C. humilis var. venusta in Southern California, and C. humilis var. jonesii in Utah and Northern Arizona. Some populations occur geographically in areas between the typical distribution of each variety and the presently accepted taxonomy inadequately addresses these populations. Using five nDNA regions, we seek to clarify relationships between current varieties and assess the pattern of variation throughout the species. Analyses including K-means clustering, principle component analysis, fields for recombination, AMOVA, and ecological niche modeling were applied. Results indicate significant genetic structure between varieties and supports recognition of C. jonesii at the species level as distinct from C. humilis. Well defined intraspecific groupings are evident in the data, with evidence supporting the recognition of an additional variety in C. humilis, and two varieties in C. jonesii. Haplotype diversity and relationships between metapopulation clusters inform conservation efforts regarding diversity within Cycladenia and offer insights into the historical demography of this genus.

Increasing sea levels and anthropogenic disturbances have caused the world’s coastal vegetation to decline 25-50% in the past 50 years. Future sea level rise (SLR) rates are expected to increase, further threatening coastal habitats. In combination with SLR, the Everglades ecosystem has undergone large-scale drainage and restoration changing Florida’s coastal vegetation. Everglades National Park (ENP) has 21 coastal plant species threatened by SLR. My dissertation focuses on three aspects of coastal plant community change related to SLR and dehydration. 1) I assessed the extent and direction coastal communities—three harboring rare plant species—shifted from 1978 to 2011. I created a classified vegetation map and compared it to a 1978 map. I hypothesized coastal communities transitioned from less salt- and inundation-tolerant to more salt- and inundation-tolerant communities. I found communities shifted as hypothesized, suggesting the site became saltier and wetter. Additionally, all three communities harboring rare plants shrunk in size. 2) I evaluated invading halophyte (salt-tolerant) plant influence on soil salinity via a replacement series greenhouse experiment. I used two halophytes and two glycophytes (non-salt-tolerant) to look at soil salinity over time under 26 and 38‰ groundwater. I hypothesized that halophytes increase soil salinity as compared to glycophytes through continued transpiration during dry, highly saline periods. My results supported halophytic influence on soil salinity; however, not from higher transpiration rates. Osmotic or ionic stress likely decreased glycophytic biomass resulting in less overall plant transpiration. 3) I assessed the best plant life-stage to use for on-the-ground plot-based community change monitoring. I tested the effects of increasing salinity (0, 5, 15, 30, and 45‰) on seed germination and seedling establishment of five coastal species, and compared my results to salinity effects on one-year olds and adults of the same species. I hypothesized that seedling establishment was the most vulnerable life-stage to salt stress. The results supported my hypothesis; seedling establishment is the life-stage best monitored for community change. Additionally, I determined the federally endangered plant Chromolaena frustrata’s salinity tolerance. The species was sensitive to salinity >5‰ at all developmental stages suggesting C. frustrata is highly threatened by SLR.

PAPER The possibilities of naturalization of rare and vanishing plants’ species are surveyed in master’s study The subject of research - The botanical gardens of Liskiava with the rare and vanishing plants’ species cultured and naturalized there. Objective of the research – Naturalized species of the plants: Turk’s-cap (Lilium martagon), medicinal angelica (Angelica archangelica), perennial satinflower (Lunaria rediviva), and ivy bedstraw (Hedera helix). Also the naturalization in site of rare plants is observed and estimated. Methods of study – Some studied plants were brought from their natural vegetation places, digging out it with the thickness of soil, some of then were sown from seeds: macro bloom finger-flower (Digitalis grandiflora), meadowy salvia (Salvia pratensis). The naturalization of these plants and capability to proliferate is also observed. Ecologist of Dzukija National park, Henrikas Gudavicius conduced to pursue the observation and researches, also rendered comprehensive information about the botanical gardens of Liskiava. Such possibilities of naturalization of rare and vanishing plants’ species were no studied in Lithuania. The conclusion could be done under the results of research: rare plants can be naturalized, just the proper place must be chosen and the observation is necessary during the first year. Keywords: National park of Dzukija, The botanical gardens of Liskiava, rare and vanishing plants’ species, naturalization.

Identifying mechanisms that determine who lives and dies is the first step in developing successful restoration techniques for rare species and endangered habitats. We studied interactions that affect establishment of native plant forbs of conservation concern at the seedling stage to support the theoretical basis for restoration activities in Pacific Northwest prairies. Specifically, we tested the hypothesis that seedling establishment is controlled by 1) competition with or 2) facilitation by existing vegetation and that the interaction is mediated in part by environmental stress. We direct-seeded or planted vegetative plugs of Lupinus oreganus, Castilleja levisecta, Erigeron decumbens, Iris tenax and Sidalcea malviflora ssp. virgata into 20 plots with a range of community compositions in high-stress upland prairies at each of three sites. We counted seedlings and estimated cover of plant functional groups as well as litter, bare soil and disturbance then used linear regression to test for effects of these factors on seedling establishment. We found evidence of indirect facilitation of grass on seedling establishment in the first year: higher accumulations of leaf litter increased seedling numbers at two sites. In the second year, there was evidence of facilitation by live vegetation and litter on seedlings at one site, but no net effect of either competition or facilitation at the other two sites. Overall, we found more evidence for positive interactions than we did for competition. In particular, litter appeared to have a positive effect on seedling establishment of L. oreganus and S. malviflora ssp. virgata. This is contrary to the common perception that litter inhibits plant establishment but supports the theory that facilitation is more common in high stress sites; practitioners should consider seeding into leaf litter at some sites. To support a robust approach to conservation and reintroduction of species with dormant seed, we characterized dormancy types and developed germination protocols for S. malviflora ssp. virgata and I. tenax. S. malviflora ssp. virgata has physical dormancy and may have physiological dormancy. Scarification followed by four weeks of cold moist stratification was effective in initiating germination. I. tenax has morphophysiological dormancy which is overcome by four weeks of warm moist stratification followed by 6-12 weeks of cold stratification. We also conducted a meta-analysis of experiments that tested pre-sowing seed scarification of L. oreganus and conclude that breaking physical dormancy prior to direct seeding does not support higher establishment relative to unscarified seeds in this species. / Graduation date: 2012