Upland Violets and Mountain Lions

The poster species for the 2024 Wildflower Festival is an attractive little plant that goes by a number of different names depending upon region and subspecies. The name upland yellow violet seems most appropriate for ours, Viola praemorsa ssp. praemorsa, as it is frequently found on hillsides. Though “yellow violet” sounds like an oxymoron, many North American species in the genus Viola exhibit yellow petals and several are found in western Oregon. Viola praemorsa is most easily differentiated by its fairly long, hairy, and ovate leaves which typically cluster around the base of the plant or extend upwards on petioles. Emily Poole has nicely illustrated the plant’s habit on this year’s Festival poster. Several hundred species of violets are known worldwide, and over two dozen can be found in Oregon. Viola is particularly interesting in that most species bear cleistogamous flowers–flowers that never open and are self-fertilized. Of course, violets also produce very showy flowers, some of which have been valued horticulturally. In Viola praemorsa, cleistogamous flowers are typically produced later in the season, following their showy, open-pollinated flowers. While one might expect that poor pollination would lead to an individual plant producing more self-fertilized flowers, a study was not able to find any correlation between pollination and the production of cleistogamous flowers. Another neat feature in the reproductive biology of violets is the production of seeds with an elaiosome, or a fleshy appendage that is rich in lipids and proteins. This elaiosome attracts ants, which harvest the seeds and carry them back to the nest to feed on. After the elaiosome is eaten, the seeds are transferred to the ants’ compost pile, providing an ideal location for germination. Elaiosomes have convergently evolved in a large number of plant species and locally are known from many woodland plants, including Trillum and bleeding hearts, all of which rely on ants for dispersal
The upland yellow violet is often associated with prairies, bluffs, and open woodlands, and can be found on Mount Pisgah in a handful of locations. Due to habitat loss from land use changes, reduction in fire frequency, and encroachment of conifers and other woody vegetation, this species has become somewhat rare in the Willamette Valley and has been listed as a species for review by the Oregon Biodiversity Information Center. Some of the Mount Pisgah locations for the upland yellow violet are near the summit ridge, where cougars (Puma concolor) are also occasionally seen by hikers. Cougars, also known as mountain lions, are extremely shy. Despite being resident on Mount Pisgah they are very infrequently encountered, and of the known encounters here, cougars have not displayed aggressive or concerning behavior. It is important to remember that we share Mount Pisgah with large predators, and it is good to know how to behave in the case of an encounter. It is also important to remember that cougar attacks are very rare. Cougar attacks have caused 28 documented fatalities in North America over the past 100 years, while cows kill about 20 people in the United States annually, mostly through trampling or kicking. In the 1960’s, overhunting had reduced Oregon’s cougar population to an estimated 200 individuals. A change in hunting regulations allowed for the population to rebound, and cougars are once again widespread across the state. These big cats are largely solitary, but recent research has suggested that they may lead more complex social lives than had previously been appreciated, including bonds formed during food-sharing, and it was found that food sharing was more common among cougars living within the territory of a dominant male. It is posited that over-hunting of cougars can disrupt these bonds and lead to more problem interactions with humans and livestock. Mount Pisgah is an important site for the conservation of a number of species that are now uncommon or rare in the Willamette Valley. Among these is the upland yellow violet. Mount Pisgah also helps to maintain the social connections of large mammals, humans and cougars alike.
– August Jackson, Interpretation Coordinator for Mt Pisgah Arboretum

Publicado el mayo 13, 2024 04:53 TARDE por ribes2018 ribes2018


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