During oil-sands mining all vegetation cover, soil, overburden and oil-sand is removed, leaving pits several kilometres wide and hundreds of metres deep. These pits are reclaimed by a variety of treatments using mineral soil or a mixed peat and mineral soil as the capping layer and planted with trees with natural colonisation from adjacent sites. A number of reclamation treatments covering different age classes were compared with a range of natural forest ecotypes to identify the age at which the treatments become similar to a natural site with respect to vegetation composition and key soil attributes relevant to nutrient cycling. Ecosystem function was estimated from plant community composition, litter decomposition, development of an organic layer and bio-available nutrients. Key response variables including moisture, pH, C:N ratios, bio-available nutrients and ground-cover were analysed by non-metric multidimensional scaling and cluster analysis to discover which reclamation treatments were moving towards or merging with natural forest ecotypes and at what age this occurs. On reclaimed sites, bio-available nutrients including nitrate generally were above the natural range of variability but ammonium, phosphorus, potassium, sodium and manganese were generally very low and limiting to ecosystem development. Plant diversity was similar to natural sites from 5 years to 30 years after reclamation, but declined as reclaimed sites approached canopy closure. Grass and forb leaf litters decomposed faster than aspen or pine in the first year, but decomposition on one reclamation treatment fell below the natural range of variability. Development of an organic layer appeared to be facilitated by the presence of shrubs, while forbs correlated negatively with first-year decomposition of aspen litter. The better restoration amendments for tailings sands involved repeated fertilisation of peat: mineral mixtures in the early years of plant establishment, these became similar to a target ecotype at about 25 years. Good results were also shown by subsoil laid over non-saline overburden and fertilised once, these became similar to a target ecotype at about 15 years. Other treatments receiving a single application of fertiliser remain entrenched in the early reclamation phase for up to 25 years.

During oil-sands mining all vegetation cover, soil, overburden and oil-sand is removed, leaving pits several kilometres wide and hundreds of metres deep. These pits are reclaimed by a variety of treatments using mineral soil or a mixed peat and mineral soil as the capping layer and planted with trees with natural colonisation from adjacent sites. A number of reclamation treatments covering different age classes were compared with a range of natural forest ecotypes to identify the age at which the treatments become similar to a natural site with respect to vegetation composition and key soil attributes relevant to nutrient cycling. Ecosystem function was estimated from plant community composition, litter decomposition, development of an organic layer and bio-available nutrients. Key response variables including moisture, pH, C:N ratios, bio-available nutrients and ground-cover were analysed by non-metric multidimensional scaling and cluster analysis to discover which reclamation treatments were moving towards or merging with natural forest ecotypes and at what age this occurs. On reclaimed sites, bio-available nutrients including nitrate generally were above the natural range of variability but ammonium, phosphorus, potassium, sodium and manganese were generally very low and limiting to ecosystem development. Plant diversity was similar to natural sites from 5 years to 30 years after reclamation, but declined as reclaimed sites approached canopy closure. Grass and forb leaf litters decomposed faster than aspen or pine in the first year, but decomposition on one reclamation treatment fell below the natural range of variability. Development of an organic layer appeared to be facilitated by the presence of shrubs, while forbs correlated negatively with first-year decomposition of aspen litter. The better restoration amendments for tailings sands involved repeated fertilisation of peat: mineral mixtures in the early years of plant establishment, these became similar to a target ecotype at about 25 years. Good results were also shown by subsoil laid over non-saline overburden and fertilised once, these became similar to a target ecotype at about 15 years. Other treatments receiving a single application of fertiliser remain entrenched in the early reclamation phase for up to 25 years.

During oil-sands mining all vegetation cover, soil, overburden and oil-sand is removed, leaving pits several kilometres wide and hundreds of metres deep. These pits are reclaimed by a variety of treatments using mineral soil or a mixed peat and mineral soil as the capping layer and planted with trees with natural colonisation from adjacent sites. A number of reclamation treatments covering different age classes were compared with a range of natural forest ecotypes to identify the age at which the treatments become similar to a natural site with respect to vegetation composition and key soil attributes relevant to nutrient cycling. Ecosystem function was estimated from plant community composition, litter decomposition, development of an organic layer and bio-available nutrients. Key response variables including moisture, pH, C:N ratios, bio-available nutrients and ground-cover were analysed by non-metric multidimensional scaling and cluster analysis to discover which reclamation treatments were moving towards or merging with natural forest ecotypes and at what age this occurs. On reclaimed sites, bio-available nutrients including nitrate generally were above the natural range of variability but ammonium, phosphorus, potassium, sodium and manganese were generally very low and limiting to ecosystem development. Plant diversity was similar to natural sites from 5 years to 30 years after reclamation, but declined as reclaimed sites approached canopy closure. Grass and forb leaf litters decomposed faster than aspen or pine in the first year, but decomposition on one reclamation treatment fell below the natural range of variability. Development of an organic layer appeared to be facilitated by the presence of shrubs, while forbs correlated negatively with first-year decomposition of aspen litter. The better restoration amendments for tailings sands involved repeated fertilisation of peat: mineral mixtures in the early years of plant establishment, these became similar to a target ecotype at about 25 years. Good results were also shown by subsoil laid over non-saline overburden and fertilised once, these became similar to a target ecotype at about 15 years. Other treatments receiving a single application of fertiliser remain entrenched in the early reclamation phase for up to 25 years. / Forestry, Faculty of / Graduate

I examined the effects of fire frequency on reptile and amphibian community composition in a periodically burned sandhill habitat in west-central Florida. Plots burned in 2003 had lower species richness, diversity, and evenness indices than plots that had not been burned during the previous six years. Community composition was different among plots burned at different times and followed a gradient of change that corresponded to the time since the last fire. Aspidoscelis sexlineata were the most abundant lizards in recently burned plots, while Scincella lateralis and Plestiodon inexpectatus were relatively more abundant in unburned plots. Gopherus polyphemus were least abundant in unburned plots. Community composition among plots was correlated with mean leaf litter cover and herbaceous ground cover. Mean percent cover of leaf litter and herbaceous vegetation responded to the time since the last fire. Fire indirectly affects community composition through changes in environmental variables, such as percent coverage of leaf litter and herbaceous vegetation.Additionally, I examined annual variation in reptile and amphibian community composition over a period of four years in the mid 1980s and again in 2004. Differences existed in number of individuals captured, diversity, and evenness among years. Community composition was different between all consecutive years except 1986 and 1987. Number of individuals captured per year and annual differences in community composition were correlated with summer rainfall. The annual pattern of variation in community composition over time was no different in unburned experimental plots than in experimentally burned treatments. The power to detect such a difference is low, however, because of low replication. No apparent loss of species occurred between the 1980s and 2004, but the abundances of two non-native species were significantly higher in 2004 than in the 1980s. A third exotic species was documented at the site for the first time in 2004. Because of the increasing number of exotic reptiles and amphibians in Florida, the site is at risk of invasions of other species.

State and Federal agencies have created sanctuaries and speed zones to help reduce manatee mortality while incorporating the recreational and commercial resource needs of these same habitats for humans. Specific habitat resources are considered necessary to increase manatee survivorship. We have only recently begun to address how manatees use some of these resources based on physiological or reproductive strategies. In this study, I quantified patterns of habitat use during seasonal and diel periods for different sex and reproductive manatee classes using data from a radio-telemetry study conducted by the Florida Fish and Wildlife Conservation Commission during 1991-1996. I used five environmental geographic data layers: bathymetry, distance to seagrass, distance to shoreline, distance to warm water refuge sites, and distance to fresh water sources, to discriminate seasonal and diel habitat use patterns for different manatee classes: males (M), females with calves (FWC), and females without calves (FNC). Mean occupancy values were calculated for environmental variable locations and seasonal, diel, and manatee class differences were tested using a Multi-Response Permutation Procedure (MRPP). Nonmetric Multidimensional Scaling (NMS) was used to visualize the ordination patterns of the manatee classes and to assess importance of correlated environmental variables. Significant differences in habitat use were noted between summer and winter based on distances to warm water, seagrass, and fresh water sources but similar habitat use patterns were exhibited within summer diel periods among manatee classes. All manatee classes appeared to have used a higher proportion of locations closer in proximity to seagrass at night than day in winter indicating a disproportionate difference in feeding bouts between diel periods. These differences may be attributed to adjusting feeding strategies to reduce thermoregulatory costs or to decrease human interactions. Differences in patterns were exhibited for the winter diel periods specifically for the FWC manatee classes during winter days. FWC had a higher proportion of locations within the warm water refuges during the day indicating a possible trade off situation between food consumption and thermal exposure. This study demonstrates coarse and fine scale patterns of variation in habitat use for manatees both seasonally and daily within winter. It also suggests that during winter months, manatees were not just utilizing their habitat but they appeared to have preferences and selection for certain habitat types. Recovery of a species is greatly enhanced when patterns of habitat use within the species' environment has been clearly defined. Understanding more specifically what types of habitats manatees choose might allow management to adjust strategies for protection of key habitats while encouraging further recovery of this species.

Grasses are widely used in revegetation to control erosion, build soil and maintain habitat. In northeast British Columbia, non-native grass species are commonly seeded to reclaim industrially disturbed sites. Widespread concern about degradation of biodiversity and key ecological processes has led to increasing value placed on native species and management practices leading to a more resilient landscape. I undertook this study to fill the restoration knowledge gap relating to native grasses in northeast BC. I did an extensive inventory of grasses on 217 sites in 2007, 2008 and 2009. Functional traits were measured in the field and in a greenhouse growth experiment. I found ninety-nine grass species occuring in the region, 70% of which are native. The number, proportion and extent of non-native grasses are increasing and four of these – Poa pratensis, Festuca rubra, Bromus inermis, and Phleum pratense represented almost a quarter of all occurrences. Several native species were common throughout the region: Calamagrostis canadensis, Leymus innovatus, Elymus trachycaulus, Poa palustris and Agrostis scabra. Other native species, including Festuca altaica, Koeleria macrantha, Pascopyrum smithii, and Schizachne purpurascens, strongly favoured intact habitats. Elevation, soil moisture regime, proportion of bare ground, and land use were significant factors related to local grass species composition and abundance. Agrostis scabra, Alopecurus aequalis, Beckmannia syzigachne, Bromus ciliatus, Cinna latifolia, Deschampsia cespitosa, Elymus alaskanus, Elymus trachycaulus, Festuca saximontana and Hordeum jubatum grew commonly on severely damaged well sites. Field measurements for Specific Leaf Area (SLA) and Leaf Dry Matter Content (LDMC) of 11 species showed an inverse correlation. Bromus ciliatus, Bromus pumpellianus, and Elymus trachycaulus had high SLA/low LDMC linked to rapid growth, whereas Festuca altaica, Deschampsia cespitosa, and Calamagrostis stricta had low SLA/high LDMC linked to slow growth and persistence. In the greenhouse experiment, Poa palustris, Cinna latifolia and Bromus ciliatus produced the most overall biomass and Pascopyrum smithii and Poa palustris produced the greatest aboveground biomass. Calamagrostis stricta, Poa palustris, Elymus glaucus, Leymus innovatus and Pascopyrum smithii exhibited clonal growth. Beckmannia syzigachne, Bromus ciliatus Cinna latifolia produced viable seed during the 135-day experiment. Considering all attributes five native species, Calamagrostis canadensis, Elymus trachycaulus, Poa palustris, Leymus innovatus, and Agrostis scabra are recommended for general restoration use in northeast B.C. Other native species show promise when matched to particular site conditions, including Alopecurus aequalis, Arctagrostis latifolia, Beckmannia syzigachne, Bromus ciliatus, Calamagrostis stricta, Cinna latifolia, Deschampsia cespitosa, Elymus glaucus, Festuca saximontana, Glyceria striata, Hordeum jubatum, Koeleria macrantha, Pascopyrum smithii, Poa alpina, Schizachne purpurascens and Trisetum spicatum. This information will be valuable to land managers interested in moving beyond reclamation to ecological restoration of sites disturbed by oil and gas development. Developing practices that are environmentally sound and socially acceptable requires ongoing botanical inventory. Plant traits may be useful in matching species to site conditions and restoration goals. Policy recommendations include phasing in of requirements to use native seed while restricting the use of agronomic species, promoting natural colonization, and supporting a native seed industry.