A5072541030- Legume Nitrogen Fixing Symbiosis
- Ecology and Vegetation Dynamics Studies
- Peatlands and Wetlands Ecology
- Soil Carbon and Nitrogen Dynamics
- Rangeland and Wildlife Management
- Plant Parasitism and Resistance
- Fire effects on ecosystems
- Agronomic Practices and Intercropping Systems
- Wildlife Ecology and Conservation
- Plant responses to elevated CO2
- Botany and Plant Ecology Studies
- Ecology and biodiversity studies
- Coal and Its By-products
- Seedling growth and survival studies
- Plant nutrient uptake and metabolism
- Forest Ecology and Biodiversity Studies
- Plant and animal studies
- Mine drainage and remediation techniques
- Forest Management and Policy
- Forest ecology and management
- Lichen and fungal ecology
- Climate change and permafrost
- Mycorrhizal Fungi and Plant Interactions
- Tree Root and Stability Studies
- Tree-ring climate responses
New York State Department of Environmental Conservation
2024
University of Manitoba
2013-2023
University of British Columbia
1996-2000
Canadian Forest Service
1998
Dalhousie University
1991-1994
Ehlers-Danlos Society
1984
Top predators can provide fundamental ecosystem services such as nutrient cycling, and their impact be even greater in environments with low nutrients productivity, Arctic tundra. We estimated the effects of fox (Vulpes lagopus) denning on soil dynamics vegetation production near Churchill, Manitoba June August 2014. Soils from dens contained higher levels (71% more inorganic nitrogen, 1195% extractable phosphorous) (242% 191% than adjacent control sites. Inorganic nitrogen decreased to both...
Abstract Understanding the natural revegetation of forests disturbed by dumping mine wastes is vital for success reclamation strategies. The Gunnar gold tailings pond in southeast Manitoba has remained largely unvegetated since was closed 1942, with limited vegetation developed on one side pond. We examined Picea mariana / Larix laricina forest that to determine how plant community develops and what changes are associated this development. Vegetation sampled along transects showed a...
Cisco (Coregonus artedi) have been extirpated from Lake Erie in North America since the 1960s, but they once supported one of largest Laurentian Great Lakes fisheries. Numerous potential impediments to rehabilitation identified, including summer habitat refugia and predation. We used acoustic telemetry investigate thermal use survival hatchery-reared adult cisco Erie. Fish were experimentally released (n = 50 per site) offshore at Dunkirk, New York, eastern basin Huron, Ohio, central basin....
The fact that temperate grasslands often contain upwards of 30 vascular plant species per m(2) yet these seem to have relatively similar life histories and resource requirements has made explaining coexistence in communities a major focus research. While the reduction competition by disturbance been popular explanation for coexistence, tallgrass prairies any level either no effect, or decreases diversity, since it favors dominant plants. Although there long speculation grassland could...
Biomass allocation patterns in plants are known to be affected by soil nitrogen availability. Since availability can depress symbiotic fixation, and fixation make plant growth independent of but is energetically costly, it unclear how nitrogen-fixing species should respond variation We examined the effect source concentration on shrub Alnus viridis subsp. crispa (Aiton) Turrill. Plants were grown with either NH 4 + -N or NO 3 – at a range low N concentrations, from 0 2 mmol·L –1 , inoculated...
There is interest in utilizing wood ash as an amendment forestry operations a mechanism to return nutrients soils that are removed during harvesting, with the added benefit of diverting this bioenergy waste material from landfill sites. Existing studies have not arrived at consensus on what effects amendments soil biota. We collected forest samples managed forests across Canada were amended evaluate arthropod, bacterial and fungal communities using metabarcoding F230, 16S, 18S ITS2 sequences...
Abstract Plants often grow under the combined stress of several factors. Salinity and herbivory, separately, can severely hinder plant growth reproduction, but effects both factors are still not clearly understood. is known to reduce tissue nitrogen content rates. Since herbivores prefer tissues with high N content, biochemical pathways leading resistance commonly elicited by salt-stress, we hypothesized that plants growing in saline conditions would have enhanced against herbivores. The...
Abstract Ecosystem engineers modify habitats through processes other than trophic interactions, such as by regulating soil nutrients, and can influence resource availability quality for organisms. Predator-mediated elemental cycling may be especially important in determining plant diversity growth ecosystems where fertility primary productivity are low. Red foxes ( Vulpes vulpes L.), top predators the Subarctic, could engineer local denning, which create biogeochemical hotspots of nutrients...
Background: Theory predicts that plants can reduce their fitness in the presence of neighbours by allocating resources to root growth, order pre-empt resource capture. A number studies have tested this idea done so using experiments where neighbour is confounded with soil volume. Aims : To avoid confounding effects and volume we adjusted these variables independently from one another. Methods: We grew Andropogon gerardii without neighbours, holding available each plant constant, compared...
Abstract Questions In most ecosystems, some organisms can be considered ecosystem engineers because they modify their physical environment in a way that affect many other organisms. Nutrient deposition may extremely important as an engineering activity nutrient‐limited environments, but this mechanism remains understudied. low‐Arctic tundra, region characterized by continuous permafrost, low‐nutrient soils, and slow nutrient turnover, Arctic foxes ( Vulpes lagopus ) concentrate nutrients on...
Plants maintain mutualistic symbioses with multiple symbiont genotypes that differ in the benefits they provide. To investigate differences effect of nitrogen-fixing Frankia on Alnus species, spore-producing (sp+) nodules from rubra Bong. and incana subsp. rugosa (Du Roi) Clausen non-spore-producing (sp–) viridis crispa (Ait.) Turrill, A. rubra, were collected each four different populations used to inoculate all three species. As expected, sp+ produced significantly more However, crispa,...
The purpose of this study was to determine whether symbiotic nitrogen-fixing bacteria and mycorrhizal fungi act synergistically improve plant performance when grown on heavy metal mine tailings. Seedlings were inoculated with Frankia, Paxillus involutus (Batsch) Fr., or a combination both in 100% peat, 1:1 mix peat tailings, tailings for 20 weeks. Mortality plants pure (15.0%) peat–tailings (17.9%) significantly greater than mortality (3.5%). rate nodulation mycorrhizae formation decreased...
Abstract Wood ash amendment to forest soils contributes the sustainability of growing bioenergy industry, not only through decreased wood waste disposal in landfills but also by increasing soil/site productivity and tree growth. However, growth studies date have reported variable responses ash, highlighting need identify proper application rates under various conditions maximize their benefits. We explored influence species, nutrient rates, time since application, stand development stage,...
Small inreases in CO2 stimulate nitrogen fixation and plant growth. Increasing soil N can inhibit fixation. However, no studies to date have tested how fixing plants perform under ancient levels (100 MYA), when evolved, with different of additions. The aim this study was assess if CO2, compared present, favors fixers over a range concentrations. Nitrogen (Alnus incana ssp. rugosa, Alnus viridis crispa, rubra) their close non-nitrogen relatives (Betula pumila, Betula papyrifera, glandulosa)...
Abstract Recent climate warming is expected to increase tree growth and productivity, substantially altering ecological function boundaries in northern ecosystems. Although largely determines the range of trees any biome, variations microsite conditions can influence on a finer scale. Red foxes ( Vulpes vulpes ) are found most terrestrial ecosystems considered ecosystem engineers through their denning activities. Added soil nutrients from prey remains, feces, urine could benefit dens...