Academic literature on the topic 'Western prairie fringed orchid Endangered plants'

Platanthera praeclara, commonly called western prairie fringed orchid, is a showy forb native to seven states and one Canadian province. The species had resisted previous attempts at propagation. Small, isolated populations in the sandhills region of western Nebraska are disjunct and visitation by natural pollen vectors appears to be in decline. Modern cultivation practices and other habitat encroachment factors, including urban development, recreational activities, and natural fluctuations in seasonal water availability all have the potential to exert pressure on current populations. Federal and state permits have allowed a limited hand-pollination study to be conducted on federal land. Hand-pollinated plants showed a greater fruit production compared to control plants receiving no human pollination assistance. Germination studies were conducted using aseptic in vitro techniques. The microscopic seeds possess testa that are extremely hard and resistant to liquid absorption, which presents challenges to germination in vitro. These challenges will be discussed. Alternating cold treatments with room temperatures appeared necessary to promote protocorm development after germination. Three media tested produced varying germination responses. Juvenile plants produced through micropropagation can offer propagules for possible future reintroduction efforts of this protected species.

An important consequence of self-compatibility in plants is that self-pollination can have deleterious effects on plant fitness because of inbreeding. We conducted a hand pollination experiment under field conditions to measure the magnitude of inbreeding depression associated with self-pollination in the rare western prairie fringed-orchid Platanthera praeclara Sheviak and Bowles. By comparing capsules and seeds resulting from cross versus self-pollination treatments, we determined that self-pollination reduces seed quality while having no detectable effect on capsule production or seed numbers. A smaller percentage of seeds resulting from self-pollination contained an embryo (18%) relative to seeds from cross-pollination (46%). Seeds that had an embryo were scored for the size of the embryo, small or large. A smaller proportion of seeds from self-pollination contained a large embryo (75%) relative to seeds from cross-pollination (92%). These results suggest that sexual reproduction and recruitment in this rare plant are dependent on the frequency of pollinator visitations that result in outcrossing.

To effectively manage an endangered plant species, managers must have an adequate knowledge of the habitat of the species and its reproductive ecology. This study describes the plant community associated with the endangered western prairie fringed orchid (WPFO) (Platanthera praeclara) in Manitoba and determine whether the plant community differed between sites and between six distances from the centre of orchid beds. In addition, this study exarnines factors which may affect the pollination ecology, specifically pollinator visitation. Assessment of orchid habitat occurred at four sites, separated by at least 800 m, in the Tall Grass Prairie Preserve (TGPP) in southeastern Manitoba in 2005 and 2006. The four sites were broadly similar in that each was dominated by graminoids (sedges, rushes, and grasses) and shared a moderate number of forb and graminoid species. The most abundant forbs included Galium boreale, Fragaria virginiana and Hypoxis hirsuta. The measures of species richness (species richness and rarified richness) varied significantly between distances from the centre of the orchid beds, but not between sites. The diversity measures (the Shannon-Weiner and Simpson indices) and the evenness measures (Shannon-Weiner evenness and rank log abundance slope) were significantly different between sites but not distances from the centre of the orchid beds. Ordination methods (Principal Components Analysis and Multiple Discriminant Analysis) showed the plant community at one site differed from that of the other sites, but the `plant community was not significantly different between distances from orchid bed centre. Pollinator (ie: sphinx moth) visitation rates, measured using seed capsule production, the presence of moth scales, and pollinaria removal, varied considerably between sites and between years. The abundance of nectar sources and larval hosts for the pollinators at the sites was not related to visitation rates. The visibility and proximity of anthropogenic light sources to orchids did not correspond with rates of pollinator visitation. Sphinx moth activity at the TGPP was not significantly correlated with weather conditions. The plant community associated with the WPFO was broadly similar at different sites, though differences in composition and diversity were evident. Controlled experiments would be useful in determining the effect of various factors, including those examined in this study, on the pollinator visitation rates to the WPFO in Manitoba.

The endangered western prairie fringed orchid, Platanthera praeclara (Sheviak and Bowles), is found in remnant tall grass prairie in southeastern Manitoba, and has a lower level of seed capsule development in comparison to more southern populations in the United States. Pollination of P. praeclara is limited to few select species of sphinx moths, Sphingidae, Lepidoptera, a group that is less abundant in comparison to other lepidopteran families. This study tested the hypothesis that the presence of ultraviolet light sources near orchids would attract more sphinx moths into orchid habitat and increase feeding activity of sphinx moth pollinators, thus increasing seed capsule production. The second part of this study measured orchid nectar quality and quantity during the bloom period and the possible link to pollination success. A significantly larger number of individual flowers and plants developed seed capsules in the ultraviolet light treatment plots (5.13+-0.42% of available flowers; 35.12+-1.74% of total plants) than the control plots (2.78 +- 0.42% of available flowers; 21.76 +- 2.58% of total plants). The intensity of the ultraviolet light treatment may have also had an effect on pollination success. Ultraviolet lights influenced seed capsule production by attracting sphinx moths into experimental plots. Results also indicated that ultraviolet light may be useful to manipulate seed capsule production for other research purposes. Nectar quality and quantity varied considerably during the study. The mean sugar concentration over the sampling season was 23.9+-0.2%; however, values ranged from a low 13% to high of 34%. Nectar sugar concentration decreased by approximately 6% as the flowering period progressed over the season. % of total plants) than the control plots (2.7g + 0.42 %o of available flowers; 2l .7 6 + 2.58 %o of total plants). The intensity of the ultraviolet light treatment may have also had an effect on pollination success.