In 1998 a long-term study of the health and reproductive ability of braya was established. Since 1998, the study has grown to include 18 study sites. At each of these sites measurements of size and reproductive output are recorded in August of each year on 30 individually tagged plant. The size of the plant is determined by measuring its basal diameter, longest leaf, and longest flowering stalk. The reproductive output of the plant is determined by measuring the number of flowering stalks, the numbers of flowers and fruits per stalk, and the seed set (# seeds/# ovules per fruit). External damage to leaves and fruit by insects is also assessed and recorded. In a situation where a plant dies, a tag is out of the ground, or a tag is lost then a new plant is tagged to keep the sample size at 30.
Research has shown that Long's braya has a higher potential for outcrossing than Fernald's braya but both species are primarily autogamous (self-fertilizing). Hybridization was also studied during hand-pollination experiments and analysis of floral morphology. Some plants were found to have intermediate floral characters (indicating hybrid individuals) and hybrid pollinations resulted in seeds being produced. Each finding from this study has effects on the conservation strategies for each species. A highly self-pollinating species with differences among populations indicate the recovery team should focus on preserving the entire range of existing populations of both species so none of the variation is lost. Conservation efforts should also focus on minimizing hybridization to prevent the potential loss of both rare species.
With current populations of all three species under threat and/or declining, it is vital that both on site (in situ) and off site (ex situ) conservation efforts are being utilized. In the past few years the Limestone Barrens Species at Risk Recovery Team has been put into place to manage these plants, however much information on these species is still lacking. The challenge is to develop precise ex situ protocols for growing these species at the Memorial University Botanical Garden. Several methods are being used to establish viable populations and maintain the genetic diversity of all three species in off site facilities. These methods include: 1. Developing protocols for the persistence of live plants at the Memorial Botanical Garden. In other words, being able to grow these plants with success at the Botanical Garden. Experimentation with soil characteristics, drainage and environmental conditions is ongoing in order to optimise growth of these plants.
 2. Seed banking. This method involves storing seed in a freezer for long periods of time. Both Braya longii and B. fernaldii seeds remain viable for several years if stored properly. Originally Salix jejuna seed was assumed to have low longevity and viability. However, preliminary work on S. jejuna indicates that seeds remain viable for much longer; this will play a critical role in our ability to develop a seed bank that preserves individuals from their entire distribution. 3. The third method includes developing tissue culture protocols for all three species. Not only does tissue culture allow these plants to grow in a sterile environment, (free of bacteria, fungus and insects) it allows the mass propagation of individuals from a very small amount of tissue.
 In the 2002 Recovery Plan the diamondback moth (Plutella xylostella), the seed maggot (Delia platura), and an unknown pathogen (possibly Fusarium species) were identified as likely threats to both braya species.
The diamondback moth is non-native to the island of Newfoundland and arrives each July on wind currents from the United States. It is an agricultural pest whose hosts are mustard crops that are often not available on the Northern Peninsula, which may explain why they have switched hosts to native brassicas such as braya.
Infestation by the diamondback moth can significantly reduce braya seed output because the moth larvae eat the plant's leaves, flowers, and fruit. Previously, the diamondback moths have not reproduced on the Limestone Barrens because the summers are cool. However, in 2004, we had a very warm summer and so there was a second generation of the moth. This resulted in a higher level of damage. Infestation rates continue to be monitored each year using pheromone traps and detailed surveys and a pest management system will be put in place if necessary.
Research has revealed that although the seed corn maggots feed on dying braya plants, they do not cause the plant to die. Studies have identified that a fungal pathogen kills the plant. This fungal pathogen has been causing a decline in one Long's braya population, but at this point, there is no known control of the pathogen. Methods to limit plant mortality are currently being investigated. Agricultural pests switching hosts to rare plant species is an unexplored threat to the persistence of rare species. In this study, the infestation rates and damage potential of each insect pest and the fungal pathogen will be collected in order to determine if they will cause a decline in the population size of braya. This information will be used to direct management actions by the Limestone Barrens Species-at-Risk Recovery Team.
 A braya killed by the fungal pathogen next to a healthy braya.
|
The reproductive biology of a rare plant species has implications to conservation management plans. The breeding system of a plant species influences the genetic diversity within and among populations of that species. For example a species that is primarily self-fertilizing may have less genetic variation within populations but more variation among populations. Conservation management plans would have to consider this and capture as much of this variation as possible.
Research (including hand-pollinations and analysis of floral morphology) has been conducted to determine the mating systems of Braya longii and Braya fernaldii.
