Imperfect Detection of a Federally Listed Endangered Dragonfly, Rapids Clubtail Phanogomphus quadricolor: Implications for Monitoring
Stephanie Allen
Ontario is home to four endangered riverine dragonflies in the family Gomphidae. Despite SARA listing recovery strategy development for each species, there has been little effort to monitor the species, determine specific threats, and, to date, no specific recovery efforts have been reported for any of the species. To determine how and when to monitor Rapids Clubtail, Phanogomphus quadricolor, field surveys were conducted at known sitess for the species. Surveys were conducted in southern Ontario for exuviae in the Grand and Nith rivers, followed by adult surveys in the Grand, Nith and Humber rivers. Occupancy modelling using PRESENCE resulted in a detection probability (p) at a known location of 0.1282 for exuviae and 0.5334 for adults during previously known emergence periods. Adult detectability was significantly and negatively affected by cloud cover. Rapids Clubtail emergence occurred over a period of two weeks in the Grand River and just one week in the Nith River. Based on this study, adult flight time in the Grand River was May 23 – June 19 and in the Nith River was May 31 – June 19, a substantially shorter flight time than published reports. This study demonstrates that survey methods that allow for occupancy modelling and imperfect detection provide a demonstrable improvement over generic guidance for rare dragonflies. Results also indicate that ongoing monitoring of Rapids Clubtail at known sites through wandering transects or checklist surveys, and employing citizen science is feasible.
A Spatial Application of the Lakeshore Capacity Model in Lake Manitouwabing
Chelsea Crundwell
The Lakeshore Capacity Model (LCM) is a tool used on inland lakes, primarily located in the Precambrian Shield, to help maintain the quality of water in recreational lakes. The model quantifies the linkages between natural P contributions, contributions from shoreline development, the water balance of the watershed, size and shape of a lake and the resultant P concentration. Lake Manitouwabing is a large, multi-basin lake located in the southern Precambrian Shield region of north-central Ontario. The lake has been classified as mesotrophic, with a mean total phosphorous (TP) concentration of 11.5 µg/L throughout the lake. However, in 2020, the lake experienced a blue-green algae bloom, leading to concern from residents regarding the health of the lake. This study seeks to determine if there is any spatial and temporal heterogeneity within the lake regarding phosphorous concentrations and water quality parameters. It is also the first to try and apply a spatially explicit application of the LCM to a lake located on the Precambrian Shield. Results indicate that there is both spatial and temporal variability within the lake. TP and soluble reactive phosphorus (SRP) spanned an 11 µg/L range between sites. TP samples collected in 2021 resulted in a mean concentration of 18.6 µg/L. Depth profiles of temperature, dissolved oxygen and oxidation reduction potential also indicated spatial and temporal heterogeneity in the lake. The spatial application of the Lakeshore Capacity worked for 5 of the 6 regions of the lake when using historic TP concentrations, but only worked for region, Middle Lake when using 2021 sampling data. The spatial differences in P forms and depth profiles within the lake may explain other inputs of TP that are not accounted for in the LCM. Loss of shoreline vegetation is thought to be the main factor controlling the increases in P throughout the lake.
LIDAR-based mapping of the streamlined bed of the Green Bay paleo ice stream, 1 Wisconsin USA
Phil Ruscica
Processing and visualization of high resolution (1.5-3.0 m) LiDAR topographic data sets using a newly developed machine learning methodology for automated analysis of streamlined subglacial terrains is used to map 33,002 individual bedforms on the bed of the 400 km long, c.100 km wide Green Bay paleo Ice Stream (GBIS: 90,000 km2: MIS 2; 29,000–14,000 years) in Wisconsin, USA. GBIS surged southwards out of the overdeepened Lake Superior Basin, along a topographically confined depression underlain by soft Paleozoic shales and pre-existing morainal topography between rising uplands of Precambrian strata and Silurian dolostones of the Niagara Escarpment. Statistical analysis of LiDAR-derived topographic data sets and elongated from 32,003 bedforms using Curvature-based Relief Separation (CBRS) and K means clustering reveals a continuum from drumlins to megascale glacial lineations, and furthermore, defines a series of streamlined surfaces, akin to those on fault planes and other surfaces experiencing progressive erosion and smoothing by frictional wear. Six surfaces (S1- S6) can be defined by their dominant bedform type and elongation, summit elevation of individual bedforms, and their relief amplitude. Relatively higher-relief streamlined surfaces (S1, S2) along the higher standing lateral margins of the bed of GBIS show weakly streamlined drumlins resulting from overriding and erosion of a pre-existing morainal topography; in contrast, lower lying surfaces are dominated by dissected (‘channeled’) multi-crested drumlins (S3, S4) that are transitional to MSGL dominated surfaces (S5, S6) which are restricted to the axial part of the ice lobe at low elevations. Mapping of surfaces S5 and S6 identifies radiating flow sets up to 5 km wide, left by faster flow units within a composite ice stream. The morphology and spatial distribution of streamlined surfaces is consistent with erosional lowering of a pre-existing topography and underlying sediments and a reduction in relief amplitude consistent with progressive erosion by 3 erodent layer of deforming subglacial debris. Streamlined surfaces are draped by end moraines that are interpreted to be the geomorphic record of erodent layer debris, being swept to the ice margin where it was thickened by aggradation, pushed and pressed into end moraines during temporary still stands. Globally, in both the modern and Pleistocene realms, drumlins and megascale glacial lineations are limited to broad topographic depressions and basins where ice overran antecedent sediment, indicating that a model of subglacial erosion provides a unifying theory for their formation.
Relationships between landscape habitat features and sciurid communities in Rouge National UrbanPark, with a focus on flying squirrels
Sonia ‘Leah’ Lee
Conservation of biodiversity is especially challenging in urban environments, where considerable natural habitat has been lost and where remaining habitats are often heavily fragmented and modified by surrounding anthropogenic influences. Fragment occupancy and habitat relationships of small mammal species were examined, with a focus on the northern and southern flying squirrels (respectively Glaucomys sabrinus and G. volans), at Rouge National Urban Park in the summer of 2021. Live trapping was performed from May to August at 19 sites, with a 6-by-4 trap grid with 40-m spacing (24 traps total) used at each site. Traps were against tree trunks at heights of 1.5 m. Flying squirrels were widely distributed in the park (11 of 19 sites), especially in the southern part of the park, and the two species sometimes occurred in the same fragment. Negative correlations of abundances were observed for two species pairs: red squirrels (Tamiasciurus hudsonicus) and eastern chipmunks (Tamias striatus) and deer mice (Peromyscus maniculatus) and white-footed mice (Peromyscus leucopus). Using the Ontario Land Cover Compilation (OLCC) to derive habitat information, several significant relationships between abundances and habitat features were observed: T. hudsonicus was significantly correlated with the amount of conifer habitat at the local (site) level, G. volans with the amount of deciduous habitat at the landscape level, and T. striatus with the amount of marsh forest at the local and landscape level. G. sabrinus were surprisingly generalist, occurring in 7 of 19 fragments, considering their association with coniferous forests typically reported in the literature. This research suggests that the relationship between flying squirrels and their habitat preferences has been altered by the urban and peri-urban environment, including the potential effects of fragmentation, grey infrastructure, and modified interspecific interactions.
Beech Bark Disease in an Unmanaged Temperate Forest: Patterns, Predictors, and Impacts on Ecosystem Function
Rosalyn Kish
Dr. Adam Martin
Beech Bark Disease (BBD) is a devastating threat to American beech (Fagus grandifolia) spreading through mixed forests in eastern North America at unprecedented rates. The advance of BBD—a tree decline disease associated with a scale insect (Cryptococcus fagisuga and Xylococculus betulae) and pathogenic fungi (Neonectria faginata and N.ditissima) complex—is leading to widespread beech tree mortality, with major consequences for forest structure and function including alterations to forest carbon (C) cycling. However, the biotic and abiotic factors that underpin the progression of BBD within unmanaged temperate forests at sub-regional scales remain unexplored. We surveyed 651 individual beech trees ≥10 cm diameter at breast height (DBH) for BBD, in a 13.5-ha unmanaged forest dynamics plot in Haliburton, Ontario, Canada, where >46,000 trees have been identified to species, mapped, and DBH measured every 5 years. For each beech tree, BBD severity was ranked on a 5-point severity index, which was then evaluated as a function of tree-level characteristics (i.e., DBH, growth rate and spatial location), and forest characteristics (i.e., topographic characteristics, wood specific gravity, and functional trait dispersion). In our dataset, the majority of beech trees were at either the insect or fungal stage of BBD, with only 22% of beech trees being free of symptoms. For beech trees ≥30 cm DBH, approximately 52% exhibited “severe” symptoms (BBD rank of 4 or 5), indicating that BBD is emerging as the primary agent of tree mortality in the forest, and is responsible for large and rapid transitions of biomass C from live- to dead pools. Tree-level characteristics including DBH and relative growth rates suggest severe BBD symptoms in larger trees with slow growth rates. We detected a spatial signature of BBD symptoms in the forest, supporting a east-to-west progression of the disease that broadly follows a gradient of increasing numbers of large-DBH beech trees. We also found elevation to be significantly, positively related with BBD severity, and community weighted means of wood specific gravity and functional dispersion to be negatively related with BBD severity. Our results improve our understanding of the factors that predict the spread and severity of a major forest disease within forest stands and show that BBD is among the most prominent drivers of C stocks and fluxes and cycling in unmanaged mixed temperate forests.
Post harvesting impacts on element concentrations and loads in streams from small central boreal Canadian watersheds
Jiaying Liu
Forest harvesting activities effects on hydrological and biogeochemical cycles have been studied for decades, though few studies have examined elemental loading in Canada across multiple watersheds simultaneously. Using data collected during the period 2019-2020, the specific element total and dissolved concentrations and loads of Be, Na, Mg, Al, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Ag, Cd, Sb, Ba, Ti, and Pb were estimated for seven small catchment sites in Canada’s central boreal region, near Dryden, Ontario. One year of pre-harvest and one year of post-harvest data are presented here. Starting from late autumn 2019 through early spring 2020, significant proportions of five of the seven sites were mechanically harvested. To test the effects of this manipulation, Randomized Intervention Analysis was applied, wherein treatment ratios between harvested and unharvested catchments were examined for differences between 2019 (pre-harvest) and 2020 (post-harvest). We find that the concentrations of Na, Mg, K, Cr, Fe, Co, Zn and As changed significantly (p < 0.05) following harvest, which were driven by stream water chemistry (e.g. DO, DOC and pH) and landscape characteristics (e.g. mean slope).
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