Sager, Eric

Wetland loss in southern Ontario, escalated by development, is putting pressure on planners as they struggle to meet development needs while maintaining a balance with regional natural heritage. Wetland offsetting, coupled with strategic environmental assessment and sustainable community planning, offers a potential solution. A combined approach of literature review, interviews, focus group, and case study with Central Lake Ontario Conservation Authority (CLOCA) allowed me to present experiences and perspectives on wetland offsetting, site selection methods, and ecosystem service priorities. The focus group looked at organizational interactions and decision-making processes during wetland offsetting. Research resulted in creation of the Strategic Wetland Offset Site Selection Score Card (SWOSSS Card). Five of CLOCA's past offsetting projects were reviewed to see what worked and what did not. Findings determined that use of strategic wetland offset site selection tools have the potential to provide an efficient means to quantify offsetting risk ahead of restoration efforts.

Author Keywords: compensation, landuse planning, offsetting, prioritization, restoration, wetlands

The damage to Sudbury's landscape from over a century of smelter and logging activity has been severe and impacts well documented. However, despite their abundance in the region, wetlands have received little attention. Recent studies have identified that nutrient limitation is as much a problem as metal toxicity and highlighted not only the importance of wetlands but also the need for more detailed studies examining the role of wetlands in the recovery of lakes. The objective of this work is to characterize the spatial and temporal variability in the geochemistry of 18 wetlands (poor fens) surrounding Sudbury, Ontario. Peat and water chemistry in the wetlands exhibited large spatial and temporal variability. Copper and Ni concentrations in surface peat decreased with distance from the largest smelter in the area, but water chemistry was also strongly influenced by natural factors such as climate, groundwater and peat carbon content. Redox processes contribute greatly to temporal variation in pore-water chemistry: the August and October campaigns were characterized by higher SO4, lower pH and higher concentrations of metals such as Ni, Cu and Mn compared with the May campaign. Other factors contributing to the temporal variability in pore water chemistry include DOC production, senescence and water source. Despite the large variability, soil-solution partitioning can be explained by pH alone for some metals. Modeling is significantly improved with the addition of other variables representing dissolved organic matter quality and quantity, sulphate concentration and hydrology.

Author Keywords: metal contamination, metal mobility, organic matter quality, peatland geochemistry

In this study, I investigate the effects of nitrogen (N) and phosphorus (P) on the nutritional stoichiometry and growth of filamentous green algae of the family Zygnemataceae in situ and ex situ. I found a mean of Carbon (C):N:P ratio of 1308:66:1 for populations growing in the Kawartha Lakes of southern Ontario during the summer of 2012. FGA stoichiometry was variable, with much of the variation in algal P related to sediment P (p < 0.005, R2 = 0.58). Despite large variability in their cellular nutrient stoichiometry, laboratory analysis revealed that Mougeotia growth rates remained relatively consistent around 0.28 day-1. In addition, Mougeotia was found to be weakly homeostatic with respect to TDN:TDP supply (1/HNP = 0.32). These results suggest that FGA stoichiometry and growth rates are affected by sediment and water N and P. However, they will likely continue to grow slowly throughout the summer despite variable nutrient supply.

Author Keywords: Chlorophyll concentration, Filamentous algae, Growth rate, Homeostatic regulation, Nutritional stoichiometry

This study examined dissolved organic matter (DOM) and labile Mercury (from diffusive gradient in thin films (DGT)) in the Quesnel river, British and the Goose creek tributary of the Churchill river, Manitoba. DOM properties were measured with optical measurements of absorption coefficient (a254), spectral slopes (S275-295, SR) and fluorescence indices (HIX, BIX, FI). The DOC proxy measurements (a254) were almost 10 times higher at the Churchill site (Mean a254 116.77 cm-1) compared with the Quesnel river site (Mean a254 12.06 cm-1) during the study periods. While DGT labile Hg concentrations at the Quesnel site (2.17 to 98.97ppt) were almost 10 times more than the levels reported at the Churchill site (0.03 to 9.06 ppt). Fluorescence indices and the rise of labile Hg concentrations in spring indicated mostly terrestrial sources of DOM at both the sites. Spectral slopes and fluorescence indices substantiated that Churchill site had high molecular weight, complex and more humic DOM compared with Quesnel. DOM at both the sites was prone to temporal variation and affected by environmental conditions. Correlation between DGT labile-Hg and DOM parameters suggested that DGT collected Hg-organic complexes along with inorganic labile-Hg complexes.

Author Keywords: Churchill, Diffusive gradient in thin films, Dissolved organic matter, Labile Hg, Mercury, Quesnel

Anthropogenic atmospheric emissions and subsequent deposition of nitrogen (N) can affect N-sensitive habitats and lead to shifts in plant species community composition. This study assessed the effects of N deposition on plant community composition for Jack pine forests across northwestern Canada and across a smaller subset of sites surrounding the Athabasca Oil Sands Region (AOSR) using 'gradient forest' analysis. Predictor influence on community composition varied depending on the scale of the study and relatively

distinct thresholds were identified for different plant groups. In the larger scale study, a total deposited nitrogen (TDN) threshold of 1.5 – 3 kg N ha-1yr-1 was well suited to protect predominantly lichen species, consistent with lichen-based critical loads from other studies. Across the smaller scale study, a TDN threshold of 5.6 kg N ha-1yr-1 was primarily associated with vascular species changepoints but did include some important N-indicator lichen and bryophyte species.

Author Keywords: critical loads, gradientForest, Jack pine, Nitrogen deposition, species composition

Ecological restoration helps managers of protected areas respond to challenges presented by factors that threaten ecological integrity and respond to residual effects of previous land use. Many protected areas require restoration on sections of the property, due to previous land use. The objective of this thesis is to present criteria that assist ecological restoration professionals in assessing the potential of restoration projects within a protected area, based on the restoration wheels from the International Principles and Standards for the Practice of Ecological Restoration. The criteria were discovered from a review of the literature and reinforced from interviews with experienced restoration practitioners and a focus group session with key members of the Haliburton Highlands Land Trust (HHLT). Based on the combination of biophysical and socioeconomic values in the restoration wheels, they are presented in the form of a five-star assessment system to create long-term restoration goals for properties of the HHLT and protected areas in general. These long-term restoration goals can be utilized in conjunction with the wheels and five-star assessment tools to prioritize restoration projects

Author Keywords: Determining Project Potential, Ecological Restoration, Evaluating Success, Haliburton, Land trusts, Restoration Wheels

Decades of acidic deposition have depleted base cation pools in soil over large parts of eastern north America, including the Muskoka-Haliburton region of central Ontario. This region has also experienced a shift in forest species composition over the past 200 years, favouring sugar maple (Acer saccharum Marsh.) at the expense of species such as white pine (Pinus strobus L.) and eastern hemlock (Tsuga canadensis (L.) Carr.). This shift in species composition may have changed soil chemistry over time due to differences in nutrient and metal inputs in litterfall. An analysis of litterfall and soil chemistry was conducted for five tree species commonly found across central Ontario. Stands were established in the Haliburton Forest & Wild Life Reserve and were dominated by one of balsam fir (Abies balsamea (L.) Mill.), eastern hemlock, white pine, sugar maple, or yellow birch (Betula alleghaniensis Britt.). Analysis of mineral soil oxides suggested that these stands were established on similar parent material. Deciduous dominated stands (maple and birch) had greater litterfall mass compared with conifer stands (fir, hemlock, and pine), generally leading to greater macronutrient inputs to the soil. Elemental cycling through the organic horizons was more rapid in deciduous stands, with base cations having the shortest residence times. This suggests that a change from greater conifer dominance to mixed hardwood forests may lead to more rapid elemental cycling and alter the distribution of elements in soil. Forests in the region are typically mixed and the resulting differences in soil chemistry may influence model predictions of soil recovery from acidification. Laboratory leaching tests indicated that both stand type and the acidity of simulated rainwater inputs influenced soil solution chemistry, with deciduous stands generally having a greater buffering capacity than sites dominated by coniferous species. Changes in soil chemistry were examined for each stand type using the Very Simple Dynamic (VSD) biogeochemical model. Simulations showed that soil base saturation began to increase following lows reached around the year 2000, and similar patterns were observed for all stands. When sulphur (S) and nitrogen (N) deposition were held constant at present rates, soil base saturation recovery (toward pre-1900 levels) was marginal by 2100. With additional deposition reductions, further increases in base saturation were minor at all sites. In conjunction with additional deposition reductions, the elimination of future forest harvesting allowed for the greatest potential for recovery in all stands. Overall, these results suggest that changes in forest cover may influence soil chemistry over time, most notably in the organic soil horizons. However, forecasted recovery from acidification is expected to follow similar patterns among stands, since differences in soil chemistry were less significant in the mineral soil horizons which compose a greater proportion of the soil profile.

Author Keywords: base cation decline, forest harvesting, litterfall, mineral weathering, soil acidification, VSD model

In this study we seek to better understand the potential effects of short-term (5-year) N fertilization on jack pine forest biogeochemistry, vascular plant community composition and to project a temporal endpoint of nitrogen leaching below the major rooting zone. Aqueous ammonium nitrate (NH4NO3) was applied above the forest canopy across five treatment plots (20 x 80 m) four times annually. The experimental deposition gradient followed those known for localized areas around the major open pit operations at 0, 5, 10, 15, 20 and 25 kg N ha-1 yr-1 over a five-year period (2011 – 2015). Nitrate recovery in throughfall was significantly higher than NH4+ (p < 0.05), indicating canopy NH4+ immobilization. There was a strong treatment effect (p < 0.05) of N on the epiphytic lichen thalli concentrations of Hypogymnia physodes and Evernia mesomorpha after five years. The canopy appeared to approach saturation at the highest deposition load (25 kg N ha-1 yr-1) during the fifth year of N additions as most N added above the canopy was accounted for in throughfall and stemflow. The non-vascular (lichen and moss) vegetation pool above the forest floor was the largest receptor of N as cryptogam foliar and thalli N concentrations showed a significant treatment effect (p < 0.05). Nitrogen in decomposing litter (25 kg N ha-1 yr-1) remained immobilized after five years, while treatments ≤ 20 kg N ha-1 yr-1 started to mobilize. Understory vascular plant cover expansion was muted when deposition was ≥ 10 kg N ha-1 yr-1. Finally, modeling suggests the forest may not leach N below the rooting zone until around 50 years after chronic addition begin (25 kg N ha-1 yr-1). The modeling results are consistent with empirical data from a high exposure (~20 - 25 kg N ha-1 yr-1) jack pine site approximately 12 km west of the experimental site that has not yet experienced N leaching.

Author Keywords: Biogeochemistry, Canopy, Deposition, Jack Pine, Nitrogen, Understory

Invasive aquatic plants can create negative ecological, economic and social impacts when they displace local vegetation, interfere with shipping and navigation and inhibit water-based recreational activities. In 2008, the first North American occurrence of the invasive plant Stratiotes aloides (Water soldier) was identified in the Trent River, Ontario. This research measured offset photosynthesis and turion germination to determine the light compensation point (5.2-5.4m) and maximum depth of colonization (4-6m) for S. aloides propagules using in situ incubations and controlled growth experiments. The effects of spring and fall chemical (Diquat) and physical (hand raking) treatments on S. aloides biomass, local macrophyte recovery and community dynamics in the Trent River were also measured. The target of a 75% minimum reduction in S. aloides biomass was not attained using any of the treatment methods and no perceivable recovery of the local plant community was observed. Significant S. aloides regrowth was recorded for both treatment methods regardless of application timing.

Author Keywords: herbicide, invasive species, macrophyte, photosynthesis, propagule

Tree harvesting alters nutrient cycling and removes nutrients held in biomass, and as a result nutrient availability may be reduced, particularly in naturally oligotrophic ecosystems. Selection harvesting is a silvicultural technique limited to tolerant hardwood forests where individual or small groups of trees are removed creating a "gap" in the forest canopy. In order for harvesting machinery to gain access to these individual trees, trees are felled to create pathways, known as skid roads. The objective of this study was to characterize differences in soil chemical and physical properties in gaps, skid roads and uncut areas following selection harvesting in central Ontario as well as documenting differences in the understory vegetation community and sugar maple (Acer saccharum) seedlings chemical composition post harvest. First year seedlings were collected for elemental analysis from unharvested areas, canopy gaps, and skid roads in 2014, eight months after harvesting. In 2015, first and second year sugar maple seedlings were collected. Soil bulk density and water infiltration were measured in the three areas of the catchment as well as soil moisture, organic matter content, exchangeable base cations, and net nitrification. Seedlings in the disturbed sites had lower concentrations of Mg, K, P, and N compared with unharvested sites and soil nitrification was significantly lower in the skid roads. Water infiltration rates in the gap and skid roads were slower than the control and concentrations of metals (e.g. Fe, Al, Ca) and litter mass increased in litter bags deployed over 335 days, likely reflecting an increase in soil erosion in the skid roads. Understory vegetation was markedly different amongst sites, particularly the dominance of Carex spp. in the skid roads. The sustainability of industrial logging is dependent on successful tree regeneration, however, increased soil compaction, establishment and growth of grasses and shrubs, as well as low nutrient concentrations in seedlings may ultimately restrict forest succession.

Author Keywords: Canadian Shield, nitrification, selection harvesting, soil compaction, sugar maple seedling, understory vegetation