Monitoring ecological restoration at the community scale provides insight into how the population dynamics and community interactions are progressing through time in comparison to a restoration’s goals and reference conditions. This study monitored the early post-restoration dynamics of a sand plain located in the Carolinian Canada ecozone called Lake Erie Farms. The restoration consisted of restoring three habitats via sculptured seeding: a mesic forest, oak woodland, and sand barren. The hypothesis of this study is that the restoration efforts have established population dynamics and community interactions consistent with successional patterns expected from comparative literature. Community ecology, directed succession, and alternative stable states are the underlying theories that provided a conceptual and theoretical lens from which to study the objectives and hypothesis. To gain insight into the community dynamics at Lake Erie Farms the vegetation abundance, seed abundance and viability of the seedbank, seed viability of the 6 most dominant species (3 most dominant native species & 3 most dominant weedy species), and soil moisture & pH were monitored. The analysis was conducted using a RMANOVA of a nested design (P > 0.001, 0.01 and 0.05) to compare the variables in relation to the site (i.e. the sum of all the quadrats), the restoration treatment nested within the site, the field nested within the site, the transect nested within the restoration treatment and the quadrat nested within the restoration treatment. The significant findings of this study include: i) the restoration treatments are producing similar results as those expected from the literature, though there is evidence of the sculptured seeding treatment accelerating the successional stage at Lake Erie Farms compared to abandoned agricultural fields in similar ecosystems because of the presence of later-successional species; ii) the control areas are less diverse than each of the restoration units (P>0.05); and iii) the soil moisture among the treatments is beginning to diverge into the desired restoration units.

The planting of native species is a common strategy for the conservation of biodiversity; it not only allows for the restoration of degraded habitat both within conservation reserves and the matrix lands between reserves, it supplements the populations of the floral species which are planted. These supplemental populations may play an important role in providing demographic security for rare species. However, the conservation of rare species depends on more than simply maintaining adequate numbers of the species: the diversity within the species must also be conserved. Although maintaining genetic diversity is increasingly a concern for formal species recovery efforts, there has been very little research done about the diversity within plantings by non-state actors. This research was undertaken to address this knowledge gap by studying the provenances of planted rare species and the activities of those who collect and grow these plants. This research was undertaken in the Carolinian zone of southern Ontario, a region with a large number of rare plant species and a large human population. Part of this study utilized semi-structured interviews with commercial seed collectors, commercial native plant growers, and non-commercial, hobbyist growers. A variety of factors limited the diversity with the seeds collected by commercial collectors. Due to difficulty in accessing information about the natural occurrences of rare species, collectors typically collected from the same, limited number of source plants. Trespassing on private property or protected lands was common to access these seed sources, although their preference for easily accessible, reliably fecund source plants on flat, mowed sites also meant that horticultural specimens were also desired. Many of these biases were passed on to commercial growers when the seed was sold by the commercial collectors. Commercial growers shared many collection practices with commercial collectors, creating similar restrictions on the diversity within their collections. However, further limitations in diversity were also created by the growers’ establishment of small populations of seed plants and by the trading of seeds and plants between growers. One boutique grower was a dominant source of seeds and plants in these trades. The limitations in the diversity within these rare species were passed onto those who purchased and planted them. This study also focused on enthusiastic native plant hobbyists and found that they not only purchased plants but collected and grew their own plants. They also traded with other hobbyists. Much of the information about where to collect seed or plants, as well as much of the seed or plants traded between hobbyists, originated with a key individual. Thus, this champion hobbyist plays a significant role in the character of planted examples of rare plant species and the genetics of the champion’s plants are heavily represented with other planted occurrences. The practices of commercial seed collectors, growers and native plant hobbyists create biases which limit the diversity within plantings of rare species. Although these plantings provide demographic security for these species, they do not represent the diversity within their remnant “wild” populations. Thus, important questions must be raised about the conservation value of these plantings. Since many of the practices of seed collectors and growers are also used when growing more common species, the diversity within plantings of these species should also be suspect. Although the lack of diversity within common species may not threaten the regional survival of the species in the short term, it may impact the ultimate success of restoration projects.

Monitoring ecological restoration at the community scale provides insight into how the population dynamics and community interactions are progressing through time in comparison to a restoration’s goals and reference conditions. This study monitored the early post-restoration dynamics of a sand plain located in the Carolinian Canada ecozone called Lake Erie Farms. The restoration consisted of restoring three habitats via sculptured seeding: a mesic forest, oak woodland, and sand barren. The hypothesis of this study is that the restoration efforts have established population dynamics and community interactions consistent with successional patterns expected from comparative literature. Community ecology, directed succession, and alternative stable states are the underlying theories that provided a conceptual and theoretical lens from which to study the objectives and hypothesis. To gain insight into the community dynamics at Lake Erie Farms the vegetation abundance, seed abundance and viability of the seedbank, seed viability of the 6 most dominant species (3 most dominant native species & 3 most dominant weedy species), and soil moisture & pH were monitored. The analysis was conducted using a RMANOVA of a nested design (P > 0.001, 0.01 and 0.05) to compare the variables in relation to the site (i.e. the sum of all the quadrats), the restoration treatment nested within the site, the field nested within the site, the transect nested within the restoration treatment and the quadrat nested within the restoration treatment. The significant findings of this study include: i) the restoration treatments are producing similar results as those expected from the literature, though there is evidence of the sculptured seeding treatment accelerating the successional stage at Lake Erie Farms compared to abandoned agricultural fields in similar ecosystems because of the presence of later-successional species; ii) the control areas are less diverse than each of the restoration units (P>0.05); and iii) the soil moisture among the treatments is beginning to diverge into the desired restoration units.

The planting of native species is a common strategy for the conservation of biodiversity; it not only allows for the restoration of degraded habitat both within conservation reserves and the matrix lands between reserves, it supplements the populations of the floral species which are planted. These supplemental populations may play an important role in providing demographic security for rare species. However, the conservation of rare species depends on more than simply maintaining adequate numbers of the species: the diversity within the species must also be conserved. Although maintaining genetic diversity is increasingly a concern for formal species recovery efforts, there has been very little research done about the diversity within plantings by non-state actors. This research was undertaken to address this knowledge gap by studying the provenances of planted rare species and the activities of those who collect and grow these plants. This research was undertaken in the Carolinian zone of southern Ontario, a region with a large number of rare plant species and a large human population. Part of this study utilized semi-structured interviews with commercial seed collectors, commercial native plant growers, and non-commercial, hobbyist growers. A variety of factors limited the diversity with the seeds collected by commercial collectors. Due to difficulty in accessing information about the natural occurrences of rare species, collectors typically collected from the same, limited number of source plants. Trespassing on private property or protected lands was common to access these seed sources, although their preference for easily accessible, reliably fecund source plants on flat, mowed sites also meant that horticultural specimens were also desired. Many of these biases were passed on to commercial growers when the seed was sold by the commercial collectors. Commercial growers shared many collection practices with commercial collectors, creating similar restrictions on the diversity within their collections. However, further limitations in diversity were also created by the growers’ establishment of small populations of seed plants and by the trading of seeds and plants between growers. One boutique grower was a dominant source of seeds and plants in these trades. The limitations in the diversity within these rare species were passed onto those who purchased and planted them. This study also focused on enthusiastic native plant hobbyists and found that they not only purchased plants but collected and grew their own plants. They also traded with other hobbyists. Much of the information about where to collect seed or plants, as well as much of the seed or plants traded between hobbyists, originated with a key individual. Thus, this champion hobbyist plays a significant role in the character of planted examples of rare plant species and the genetics of the champion’s plants are heavily represented with other planted occurrences. The practices of commercial seed collectors, growers and native plant hobbyists create biases which limit the diversity within plantings of rare species. Although these plantings provide demographic security for these species, they do not represent the diversity within their remnant “wild” populations. Thus, important questions must be raised about the conservation value of these plantings. Since many of the practices of seed collectors and growers are also used when growing more common species, the diversity within plantings of these species should also be suspect. Although the lack of diversity within common species may not threaten the regional survival of the species in the short term, it may impact the ultimate success of restoration projects.

The variation in community composition among sites is often used to gain insight into the processes of plant community assembly. In this study, we looked for evidence of environmentally and spatially mediated community assembly mechanisms in a temperate forest in eastern North America. To test this, we measured, identified and mapped all woody stems ≥1 cm in diameter at breast height (DBH) in 12 ha of a 20 ha forest plot. We used principal coordinates of neighbor matrices (PCNM) to obtain variables that modelled spatial processes (eg. dispersal, drift) at the community level. Topographic variables (slope, elevation, convexity, aspect) were used to model environmental conditions. Variation partitioning was used to isolate the unique and shared effects of topographic and spatial variables on community composition. We were also interested in studying how associations with the environment change with tree size. For this we assessed the abundance of a subset of focal species in response to topography as well as human disturbance. Species abundance were divided into three stem size classes: small (< 5 cm), medium (≥5 cm and < 15), and big (≥15 cm). We found that topography and space jointly explained 63% of the variation in community composition. This variation was almost entirely spatially structured with the component of pure topography only contributing 1% to the total explained variation. A redundancy analysis showed that slope and elevation were the most important topographic variables structuring the distribution of trees. The focal species had largely independent distributions across the environmental gradients and three of the five species showed within-species differences associated with size class effects on the relationship with topography and human disturbance. The implications of these results are relevant to conservation efforts and suggest that large contiguous areas of heterogeneous environments are essential in maintaining biodiversity. / Thesis / Master of Science (MSc)

<p>Continuous measurements of carbon fluxes and meteorological variables were made at a newly initiated flux tower site at an oak-dominant temperate deciduous forest in Southern Ontario, Canada from January to December 2012. Results indicate this forest was a moderate carbon sink in 2012. Annual values of net ecosystem productivity (NEP), gross ecosystem productivity (GEP) and ecosystem respiration (R) were 263 ± 30, 1192 and 922 g C m^-2, respectively. An unusual warm period in March caused a strong increase in R. Erratic peaks of daily air temperature in April also increased R. A drought in July and early August reduced NEP rates when soil moisture values reached the lowest point of the year in late July and early August (minimum 0.023 m³ m^-3). This decrease in NEP was mostly caused by a decrease in GEP, rather than increased R. Water use efficiency at this deciduous forest was 2.86 g C kg^-1 H₂O, indicating conservative water use by the forest. Downwelling photosynthetic active radiation (PAR) was a dominant environmental control on photosynthesis, followed by air temperature and vapour pressure deficit, except in extreme dry periods when soil water stress affected carbon uptake. Extremely cloudy days in the growing season resulted in net carbon release due to low photosynthetic uptake values. Results indicate that large climatic fluctuations in this region may cause high instability in photosynthetic carbon uptake and release from soil carbon pools. This study helps to evaluate and quantify the responses of deciduous forests in the Great Lakes region to future climate change and extreme weather events.</p> / Master of Science (MSc)