Topic
Braya longii
About: Braya longii is a research topic. Over the lifetime, 5 publications have been published within this topic receiving 31 citations. The topic is also known as: Long's braya.
Papers
Dissertation•
1 Oct 2014
TL;DR: In this article, the authors focused on the limestone barrens of Newfoundland (Canada), an ecosystem that represents a biodiversity hotspot and hosts endemic plant species, e.g. the endangered Braya longii.
Abstract: Restoring ecosystems and habitats in human-altered landscapes is challenging where reference sites to guide restoration can be limited or absent. The current shift in restoration theory to a dynamic reference alleviates some of this concern, acknowledging systems are not static. However, historical references are still useful as restoration targets when relatively intact. I applied this principle here, focusing on the limestone barrens of Newfoundland (Canada), an ecosystem that represents a biodiversity hotspot and hosts endemic plant species, e.g. the endangered Braya longii; human activities have degraded its critical habitat.
Historical aerial photographs were used to depict landscape topography prior to substrate removal, and identify intact reference sites. Identified reference sites were characterized in terms of substrate, nutrient and vegetation composition, and topography through field observations and measurements. To test protocols to restore the complex small-scale disturbance regime, substrate manipulation experiments were constructed and monitored for frost heave and cycles. Experiments were also seeded with native flora, including B. longii to determine an effective means of re-introduction following restoration.
Limestone barrens occur sparsely on the landscape atop ancient beach ridges. Low potential habitat (10%) was observed at the study site in 1948, of which slightly less than half was degraded by quarry activity and road construction by 1995. Remnant high quality habitat identified in aerial photos and described through field surveys is characterized by frost heave and sorting, high silt/clay and bare ground cover, and low organic content. Degraded sites and overburden material differed from the reference iii
site in terms of vegetation, substrate and nutrient composition. In addition, substrate treatments to restore small-scale disturbance that lacked added overburden material demonstrated similarities to the reference site in terms of the average number of frost cycles and duration suggesting partial recovery of cold-soil processes. The seeding experiments with native flora, including the endangered endemic B. longii, resulted in low percent emergence. However, more seeds are expected to germinate in subsequent years given germination syndromes.
This thesis emphasizes the need for human intervention, rather than a non-intervention expecting regeneration given the absence of vegetative and natural disturbance recovery towards limestone barrens. It also recommends that overburden material not be used to restore soil and substrate as it will hinder progression along the target limestone barrens trajectory. Overall, the recommendations provide a baseline methodology to restore limestone barrens habitat in degraded quarry sites, addressing the Federal Recovery Strategy’s target to expand and restore critical habitat, natural freeze-thaw disturbance, and B. longii within its historical range.
3 citations
Dissertation•
1 Jan 2006
TL;DR: Not only was a successful protocol established for survival of S. jejuna cuttings established, but the germination study provided evidence that the seed is viable for up to 9 months if stored in a freezer at -20°C.
Abstract: The Limestone Barrens of the Great Northern Peninsula of Newfoundland, Canada contains many rare plant species. The Great Northern Peninsula (GNP) contains 114 rare plant species; in fact this is the only place in Newfoundland and Labrador where 29 of these 114 rare plant species can be found (Bouchard et al., 1991). Part of this area is considered critical habitat (meaning it is necessary for the survival or recovery of a listed species) for three world endemics: Braya longii (endangered), Braya fernaldii (threatened) (Brassicaceae), and Salix jejuna (endangered) (Salicaceae) (COSEWIC, 2005). These species are listed by The Committee on the Status of Endangered Wildlife in Canada (1997 and confirmed in 2000 for both Braya species; 2001 for Salix jejuna) as well as the Provincial Endangered Species Act (2002) and federal Species at Risk Act 2003. The goal of this study was to develop reliable ex situ protocols for the growth and maintenance of these three listed species. Both Braya species did not grow sustainably in captivity; therefore, through analysis of natural soil nutrient content and particle size, a reliable soil mix (1:1 mix of braya mix to crushed limestone) was produced that mimicked natural growth. Based on studies of other willow species Salix jejuna seed was assumed to have low longevity and viability which is why a main focus of developing an ex situ population of S. jejuna was on establishing a protocol for the survival of cuttings (Arya et al., 1988; Maroder et al., 2000). Not only was a successful protocol established for survival of S. jejuna cuttings, but the germination study provided evidence that the seed is viable for up to 9 months if stored in a freezer at -20°C. In light of this a seed gene bank may be possible with S. jejuna seed.
1 citations
TL;DR: Conservation strategies should focus on preserving populations throughout the entire range of each species in order to capture genetic variation among populations, and human activities that promote the population homogenisation should be minimized.
TL;DR: There is a need for both the conservation and agricultural communities to cooperate in mitigating the impacts of these pests on native biodiversity, as high summer air temperatures and low precipitation allowed this pest to become multivoltine, resulting in additive damage to braya individuals.
Dissertation•
1 Sep 2002
TL;DR: Evidence of population differentiation in floral morphology was found for both species and potential hybridization was indicated by floral morphology and hand-pollinations and the results of this study provide guidance for potential conservation management tools.
Abstract: The closely related, endangered Braya longii and threatened Braya fernaldii (Brassicaceae) are endemic to the limestone barrens of the Great Northern Peninsula of Newfoundland. This project determines potential breeding systems, levels of population differentiation, potential hybridization between these species and implications for conservation management. Morphological species differences are also summarized to ensure proper identification of new populations. Results indicate field identification using only single morphological characters is insufficient to unambiguously identify species. Both species were found to be primarily autogamous but B. longii has a greater potential for outcrossing than B. fernaldii. Cleistogamy was found to occur within some populations of B. fernaldii, but not in B. longii. Evidence of population differentiation in floral morphology was found for both species and potential hybridization was indicated by floral morphology and hand-pollinations. The results of this study provide guidance for potential conservation management tools and must be addressed before reintroduction and population restoration are implemented.
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2014 | 1 |
| 2009 | 1 |
| 2006 | 2 |
| 2002 | 1 |