Aspen Parkland Research Articles

Neoichnology of a Lake Margin in the Canadian Aspen Parkland Region, Cooking Lake, Alberta

Neoichnology of a Lake Margin in the Canadian Aspen Parkland Region, Cooking Lake, Alberta

Native seed mix richness impacts revegetation of reclaimed land

Interest in using native plant species for land reclamation and ecological restoration continues to increase. Yet sufficient knowledge of characteristics of native species for revegetation, specifically their response in field settings, continues to lag. Thus our study was conducted to determine whether the richness of native seed mixes impacted plant community development following reclamation in the Aspen Parkland ecoregion of Alberta, Canada. Four seed mixes were used: mix I with 6 grasses, mix II with 10 grasses, mix III with 6 grasses and 10 forbs, and mix IV with 10 grasses and 10 forbs. Each seed mix was designed with equal amounts of pure live seed for each species. After two growing seasons, seed mix richness generally had little or no effect on seeded species richness, individual seeded species, density, non-seeded species density, and ground cover, except for seeded forbs. Seed mixes II and III, with moderate species richness, provided the most benefit for developing species rich communities. Seeding with high species richness is more expensive, sometimes difficult to procure seed, and may not associate with communities of greater species richness, negating their need.

Reclamation of an eroded lakeshore slope using small vegetation islands and terraces

Bioengineering approaches to slope stabilization involve biological and mechanical methods with low impact on the environment and landscape. Slope stabilization using vegetation patches or islands can greatly decrease runoff and soil erosion on an eroded lake shore. While vegetation islands showed promise for forest and grassland reclamation, they have rarely been used on eroded lake shores. A study was conducted to determine whether bioengineering using native vegetation islands and terraces could successfully revegetate and stabilize a severely eroded lake shore slope in the central aspen parkland, Alberta, Canada. Three gullies and three slopes were terraced using pressure treated planks, then transplanted with non-dormant (mid-August) and dormant (mid-October) 20 cm diameter vegetation islands in a soil amended with 25% (by volume) compost. Volumetric water content was significantly less in lower slope positions than upper slope positions, and sediment transport to lower slope positions was much reduced. After one year, both non-dormant and dormant transplanted islands survived and established on the terraced slope, under relatively inhospitable growing conditions. Although non-dormant islands had significantly lower vegetation mortality (10% or less) than dormant islands on both slopes and gullies, no differences in health and vigour were found by the end of the study. Overall plant species number on the site increased during the study. Graminoid species densities increased, while those of forbs, shrub and tree species declined in the transplanted vegetation islands. Non-dormant islands had greater graminoid density than dormant islands, where Poa pratensis was the dominant species in the islands. Bioengineering with vegetation islands and terraces can assist in trapping runoff and sediment, and accelerate establishment of a diversity of plant species and groups relative to traditional revegetation methods.

Seeding season and mowing affect native plant community development on reclaimed aspen parkland

ABSTRACT Land use intensification and rising production inputs continue to negatively affect many ecosystem services with significant challenges to restore these ecosystem services in the disturbed landscape. Using native species to revegetate disturbed ecosystems continues to gain momentum. An understanding of the role of seeding season and mowing in native plant community development is required to improve reclamation success. Research using 20 native grasses and forbs was conducted to determine how seeding season (fall, spring) and mowing (mowed, unmowed) influenced revegetation of grassland reclamation sites in Alberta, Canada. Species density, biovolume, richness and ground cover were assessed over two growing seasons. Density, biovolume and species richness of seeded grasses and forbs were generally higher in spring than fall seeded treatments, whereas non-seeded grasses and forbs were lower in spring seeded treatments. During the first growing season, mowing increased seeded species density and biovolume and decreased non-seeded species biovolume, with no effect on seeded species in the second growing season. Mowing and fall seeding decreased bare ground in the second growing season. The outcomes of this study suggest grasses and forbs were more successful when spring seeded versus fall seeded, and beyond the first growing season the influence of mowing was negligible.

Differences in the reproductive output and larval survival of Rocky Mountain wood ticks (Dermacentor andersoni) and American dog ticks (Dermacentor variabilis) from prairie populations near their northern distributional limits in western Canada.

The effects of temperature and relative humidity (RH) on female reproductive output, egg development and larval survival were determined for Rocky Mountain wood ticks (Dermacentor andersoni) from a prairie population (Chin Lakes, Alberta, Canada) near the northern distribution limit of this species. The responses of D. andersoni eggs and unfed larvae to different temperature (25 or 32°C) and RH (35, 55, 75, 85 or 95%) regimes were compared to our previously published data (Diyes et al. 2021) for a northern prairie population of American dog ticks (Dermacentor variabilis). Oviposition by D. andersoni females took 21-30 days at 25°C and 95% RH compared to 10-21 days for D. variabilis. The number of eggs laid by female ticks was strongly dependent on their engorgement weight, and D. andersoni females produced more eggs than D. variabilis females of an equivalent body weight. Eggs of D. andersoni took less time to develop at 32°C than 25°C with ≥ 85% RH, and hatched faster than those of D. variabilis. Larval survival times declined as temperature increased and RH decreased, but D. andersoni survived longer at 32°C and ≤ 75% RH than D. variabilis. The interspecific differences in responses to the same temperature and humidity regimes indicate that D. andersoni is xerophilic, whereas D. variabilis is hydrophilic. Hence, 'prairie' populations of the Rocky Mountain wood tick occur in the drier grassland ecoregions but are absent in Aspen Parklands Ecoregion which is located to the north and east of the distributional range of D. andersoni.

218 Methane and Carbon Dioxide Emissions from Crossbred Beef Cattle Fall-Grazed on Native Aspen Parkland Pastures

Abstract Over 20 M ha of grazing land is utilized for beef production in western Canada, significantly contributing to the Canadian economy. Cattle are recognized for contributing to methane (CH4) and carbon dioxide (CO2), and individual animal contribution varies with several factors, one of them being feed efficiency as measured using residual feed intake adjusted for off-test backfat thickness (RFIfat). Given that commercial cattle spend a large portion of their production lifecycle grazing on diverse pastures in western Canada, understanding whether and how RFIfat measured in drylot and CH4 emissions reflect animal performance on pasture remains essential. This study quantified CH4 and CO2 production from beef cattle while grazing diverse diets on open-range aspen parkland pastures during fall. Cattle had been previously measured for RFIfat in drylot. Production of CH4 and CO2 (g/day) from crossbred beef cows (n = 22, with a range of -2.2 to +1.3 kg DM/day in RFIfat) and replacement heifers (n = 15; with a range of -2.6 to + 3.0 kg DM/day in RFIfat) were monitored using the GreenFeed emissions monitoring system over 40 days while grazing on native rangeland (70 ha) in the fall of 2022. Fall grazing was divided into two 20 ± 1 day' grazing periods; 20 days in September (SEP) vs. 20 days in October (OCT). Total spot measurements of CH4 and CO2 emissions in SEP and OCT were 1,096 vs. 1,054 for cows and 644 vs. 571 for heifers, respectively. The average number of daily visits per animal to the GreenFeed unit for cows and heifers were 2.8 ± 0.1 vs. 2.5 ± 0.1 in SEP, and 2.5 ± 0.1 vs. 2.0 ± 0.1 in OCT, respectively. Cows had greater average daily CH4 (SEP: 268.4 ± 6.1 vs. 196.1 ± 4.3; OCT: 243.9 ± 6.1 vs. 185.0 ± 4.3 g/day) and CO2 emission (SEP: 9,105.0 ± 143.1 vs. 6,485.3 ± 108.6; OCT: 8,544.3 ± 143.2 vs. 6,308.7 ± 108.9 g/day) than heifers (all P < 0.01). A negative relationship was evident between the CH4 emission and RFIfat in heifers (SEP: R2 = 0.043 vs. OCT: R2 = 0.014; P < 0.01), as well as CO2 emission and RFIfat (SEP: R2 = 0.083 vs. OCT: R2 = 0.020; P < 0.01), although the amount of variation explained by RFIfat is very small and is in disagreement with previous data. We speculate that the decline in CH4 and CO2 emissions from cattle in Oct might be due to various factors, including but not limited to changes in overall intake, daylight hours, air temperature, plant community, feeding and ruminating patterns, and rumen microbial profiles. Further analysis of forage quality, step counts, and GPS location, as well as rumen bacterial community, may shed more light on methane production in the fall.

Bison and elk spatiotemporal interactions in Elk Island National Park

Elk Island National Park (EINP) is a fenced park in the Beaver Hills UNESCO Biosphere Reserve of central Alberta where aspen parkland is being conserved. This area maintains high densities of native ungulates including elk (Cervus elaphus), bison (Bison bison bison, B. bison athabascae), moose (Alces alces), white-tailed deer (Odocoileus virginianus), and mule deer (O. hemionus). Our objective was to evaluate spatiotemporal overlap and interspecific interactions between bison and elk in EINP using camera traps. Bison and elk have overlapping habitat use and diet and are the primary focus of ungulate management in EINP. We examined distributions of both species in relation to season, landscape characteristics, anthropogenic features, and heterospecifics using generalized linear models (GLMs). We then examined seasonal daily activity patterns of bison and elk and calculated the degree of overlap. The spatial analysis revealed that bison counts were positively associated with higher proportions of open habitats across seasons and in areas farther from water in summer and fall but had no associations with distance to water during winter. Bison removal year (years during which bison removals were conducted by Parks Canada) was a significant predictor variable for bison counts in winter when the bison roundup takes place. Elk avoided areas with high linear feature density across seasons. During fall and winter, we observed higher elk counts associated with bison presence. Temporal activity patterns revealed that elk were crepuscular in all three seasons, but bison activity patterns varied with diurnal activity being more common in the summer, crepuscular activity in winter, and intermediate activity patterns during fall. Coefficients of overlap between elk and bison were high in all three seasons with the greatest difference in daily activity patterns in summer and the highest overlap in winter when both species showed strong crepuscular activity. Despite the fenced perimeter in EINP resulting in high ungulate densities, limited dispersal, and low predation, our data show patterns of habitat use and interactions between bison and elk that were similar to those in other systems. Spatiotemporal partitioning does not appear necessary for coexistence of bison and elk in the aspen parkland.

An invasive grass and litter impact tree encroachment into a native grassland

AbstractQuestionsWoody plant encroachment and invasive plants are two critical factors that negatively impact grass‐dominated ecosystems. While studies have extensively investigated these factors individually, research on how invasive species impact the susceptibility of grasslands to encroachment is less common. Using the aspen parkland, an endangered savannah‐type ecosystem, we asked how the presence of a widespread invasive grass in North America, smooth brome (Bromus inermis), impacted the growth and survival of one‐year old trembling aspen (Populus tremuloides) seedlings. We also asked if plant litter was a potential mechanism of inhibition (as has been proposed for brome litter) or coexistence (as has been hypothesized for aspen litter) in this system.LocationAlberta, Canada.MethodsWe used a manipulative experimental approach to determine if the survival and subsequent growth of planted aspen seedlings was impacted by the presence of smooth brome and manipulation of litter amount and type.ResultsWe found that the presence of smooth brome reduced aspen survival by 57% compared to uninvaded habitats, likely mediated by reduced soil moisture, while litter manipulation had no effect on survival. For surviving seedlings, local context had complex impacts on growth; the addition of aspen litter to brome‐invaded communities increased seedling growth while aspen litter additions to native communities resulted in decreased growth.ConclusionThese results suggest that invasion by smooth brome will alter the dynamics of aspen establishment in this system, potentially leading to significant changes to this already endangered landscape. Though smooth brome may serve as a barrier to aspen establishment, accumulation of aspen litter from nearby stands to brome patches could lead to faster growth of seedlings in invaded areas at the edge of existing aspen stands. Our results also suggest more generally that the impact of invasive plants on the establishment of native woody plants can be dependent on litter inputs.

Presence of a dominant native shrub is associated with minor shifts in the function and composition of grassland communities in a northern savannah.

Ecosystems are spatially heterogenous in plant community composition and function. Shrub occurrence in grasslands is a visually striking example of this, and much research has been conducted to understand the functional implications of this pattern. Within savannah ecosystems, the presence of tree and shrub overstories can have significant impacts on the understory herbaceous community. The exact outcomes, however, are likely a function of the spatial arrangement and traits of the overstory species. Here we test whether there are functional linkages between the spatial patterning of a native shrub and the standing biomass, community composition, and overall nutrient cycling of a neighbouring grassland understory communities within the Aspen Parkland of central Alberta, Canada. In a paired grassland-shrub stand study, we found the native shrub, Elaeagnus commutata, has relatively few stand-level impacts on the composition and standing biomass of the ecosystem. One factor contributing to these limited effects may be the overdispersion of shrub stems at fine spatial scales, preventing areas of deep shade. When we looked across a shrub density gradient and incorporated shrub architecture into our analyses, we found these shrub traits had significant associations with species abundance and root biomass in the understory community. These results suggest that stem dispersion patterns, as well as local stand architecture, are influential in determining how shrubs may affect their herbaceous plant understory. Thus, it is important to incorporate shrub spatial and architectural traits when assessing shrub-understory interactions.

Modification of plant communities by bison in Riding Mountain National Park

ABSTRACT Plains bison (Bison bison bison) are suspected to have played an important role in maintaining and structuring the plant communities throughout the Aspen Parkland. We examine the effects of a fenced bison herd on grassland plant communities in Riding Mountain National Park, Manitoba, Canada. We focus on the relationship between bison and woody plant encroachment along the forest-grassland ecotone, and on the effects that short- and long-term occupation by bison have on Festuca hallii grassland communities including the effects of bison reintroduction to a grassland area ungrazed by bison for 165 years. We found limited impacts of bison on the shrub community at the forest grassland edge. Bison rarely entered areas with dense, tall shrub understories, and thus bison cannot be a major factor controlling the ecotone. Shrub stem mortality due to fire may be a necessary precursor to bison effectively mitigating woody encroachment in the Aspen Parkland. We found limited short-term impacts of bison on grassland communities, with reduced sward heights but no change in composition. The long-term (>80 year) presence of bison was associated with greater species richness, reduced litter accumulation, and a distinct plant community composition compared to areas without bison impacts.

Prioritizing Invasive Forest Plant Management Using Multi-Criteria Decision Analysis in Minnesota, USA

Invasive plants are a concern in many forest ecosystems because they can impact tree regeneration and recruitment, alter hydrology, and degrade wildlife habitats. Management efforts are generally planned locally, based on the severity of the infestation, species involved, and characteristics of the forest stand. A broad, landscape-level context can provide additional information and help with planning efforts but is often lacking. In this study, we estimated landscape-level priorities for the management of five invasive forest plants in Minnesota. We used a multi-criteria decision analysis approach to integrate plant distribution models and data with geographic information about areas of conservation concern, recreational areas, and the economic benefits of treatment. The results varied across Ecological Classification System provinces and Minnesota native plant community classes. Four of the five invasive plants considered demonstrated an abundance of Medium- and High-priority areas for management in the Eastern Broadleaf Forest province of Minnesota. The average priority was generally lower in the Prairie Parklands and Tallgrass Aspen Parklands provinces, with Rhamnus cathartica as the only species demonstrating Medium or higher priorities in the latter. The mean priorities were Medium or higher for R. cathartica and Frangula alnus in mesic hardwood community types across the state, in addition to several fire-dependent systems. The priority distribution was most limited for Rosa multiflora, where the only Medium or higher priority results were found in a mesic hardwood system in the southeastern corner of the state. The results presented here highlight broad-scale patterns that can provide a synoptic overview of invasive plant priorities at the landscape scale.

Spatial patterns of temporal changes in Canadian Prairie streamflow using an alternative trend assessment approach

Changes in Canadian Prairie streamflow, particularly trends over time, have not been well studied but are particularly relevant for food and water security in this vast agricultural region. Streamflow records for this region are often unsuitable for conventional trend analysis; streams are often intermittent and have only a few days per year with flow, and stations operate only during the warm season, because of a lack of flow during the very cold Prairie winter. This study takes an alternative approach; streamflow data for the period from March to October for individual years between 1910 and 2015 from 169 hydrometric stations from the Prairie and adjacent areas in Canada were converted to annual cumulative runoff series. These 5895 individual station-years were then clustered based upon their shape, using dynamic time warping. Three clusters of cumulative annual runoff were found; the first and most common type has infrequent days with flow and low total annual runoff [0–50 mm], the second has more days with flow and slightly greater runoff [48–175 mm], and the least common third type has the fewest days without flow, includes perennial streams, and has much greater annual runoff [>173 mm]. For each hydrometric station a time series of annual cluster memberships was created. Trends in the fractions of cluster types were determined using logistic regression, with spatial groupings of these time series over five-year periods. Trends in the fractions of types within an ecoregion indicate spatially consistent and organized changes in the pattern of runoff over the region. In the western Canadian Prairies, particularly in the Mixed Grassland and Cypress Upland ecoregions, drying is occurring, as indicated by the increased frequency of the dry type. In the northern and eastern Canadian Prairies, conditions are shifting to greater runoffs, particularly in the Aspen Parkland, where the wet types are increasing in frequency.

Passive and Active Surveillance for Ixodes scapularis (Acari: Ixodidae) in Saskatchewan, Canada.

Passive and active surveillance for the blacklegged tick, Ixodes scapularis Say, in the Canadian province of Saskatchewan was conducted over a 9-yr period (2009-2017). More than 26,000 ixodid ticks, representing 10 species, were submitted through passive surveillance. Most (97%) of these were the American dog tick, Dermacentor variabilis (Say). Of the 65 I. scapularis adults submitted, 75% were collected from dogs. Infection rates of Borrelia burgdorferi, Anaplasma phagocytophilum, and Babesia microti in I. scapularis were 12%, 8%, and 0%, respectively. Although the I. scapularis submitted by passive surveillance were collected from five of seven ecoregions in central and southern Saskatchewan, they were most frequent in the Moist Mixed Grassland and Aspen Parklands. In contrast, no I. scapularis were collected from the extensive field sampling conducted at multiple sites in different ecoregions across the province. Hence, there is no evidence of I. scapularis having established a breeding population in Saskatchewan. Nonetheless, continued surveillance for blacklegged ticks is warranted given their important role as a vector of medically and veterinary important pathogens, and because they have recently become established across much of the southern portions of the neighboring province of Manitoba.

Multiscale effects of wetland availability and matrix composition on wetland breeding birds in Minnesota, USA

Abstract The increasing intensity of wetland stressors in the Upper Midwestern United States hastens the need to understand how matrix composition influences wetland bird occurrence and abundance. The optimal spatial scale for assessing species–habitat relationships is not always apparent, but may affect inference about wetland use and suitability. We developed occupancy and abundance models, accounting for imperfect detection, for 9 wetland bird species breeding in Minnesota. We evaluated land cover associations at 3 spatial scales (12.6 ha, 50.3 ha, and 4,000 ha), quantified species-specific sensitivity to wetland availability and matrix habitat composition (agricultural and developed land covers), and assessed ecoregional variation in occupancy and abundance. Amount of wetland cover was positively associated with occupancy of 89% of species and with abundance of 67% of species, but the spatial scale of support differed among species. American Bittern (Botaurus lentiginosus), Pied-billed Grebe (Podilymbus podiceps), and Wilson’s Snipe (Gallinago delicata) in particular were negatively impacted by anthropogenic land uses within the surrounding matrix, indicating a need to shift wetland conservation planning from the site scale to the landscape scale to capture pertinent drivers of wetland bird habitat use. Mean expected occupancy across all species was greatest in the Prairie Pothole Region (PPR), suggesting that restoration efforts within this ecoregion are likely to maintain wetland bird diversity. However, given the minimal total wetland availability and predominantly agricultural matrix in the PPR, protecting wetlands and upland buffers in the Aspen Parklands or Boreal ecoregions may represent a better investment for agricultural-sensitive species such as American Bittern, Sandhill Crane (Antigone canadensis), and Wilson’s Snipe. Our modeling approach provides a multi-species framework for identifying habitat management priorities; future applications at broader spatial extents can continue to improve wetland bird conservation in a region with high rates of wetland loss and degradation.

Boreal Sand Hills are Areas of High Diversity for Boreal Ants (Hymenoptera: Formicidae)

The boreal forest in Canada comprises a wide variety of ecosystems, including stabilized (overgrown) sand dunes, often referred to as sand hills. Globally, sandy soils are known for supporting a high diversity of invertebrates, including ants, but little is known for boreal systems. We used pitfall trap sampling in sand hill, aspen parkland and peatland ecosystems to compare their ant diversity and test the prediction that areas with sandy soils have higher invertebrate diversity compared to more mesic/organic soils. Overall, sand hills had ~45% more ant species compared to other sampled ecosystems from Alberta. Similar to other studies, local canopy cover within sand hills was found to be inversely related to ant species richness and diversity. Although sand hills are rare across the region, they are high biodiversity areas for ants, with the sand hills of north-central Alberta having higher species richness of ants compared to other studied areas in Canada.

Postbreeding movement patterns and habitat use of adult Wood Frogs (Lithobates sylvaticus) at urban wetlands

Habitat loss and degradation linked to urbanization threaten amphibian populations globally, yet studies examining amphibian behaviour and habitat use in cities are rare. Through the use of radiotelemetry, we examined the postbreeding (May–October) movement behaviour and habitat use of adult Wood Frogs (Lithobates sylvaticus (LeConte, 1825)) at natural and constructed urban wetlands in Edmonton, Alberta, located in the semiarid, aspen parkland of Canada. Movement from breeding wetlands was limited, with most tracked individuals remaining within 25 m of ponds in grassy riparian areas. Long-distance migratory movements were rare and only occurred at natural sites with relatively high proportions of forested land surrounding wetlands. In general, tracked frogs showed a preference for habitat close to water that provided shelter from desiccation and predation (e.g., unmowed grass and stands of shrubs). Our findings have implications for the management of wetlands and conservation of amphibian populations in urban environments.

Increased Bufflehead (<i>Bucephala albeola</i>) Breeding Activity in Minnesota

Buffleheads (Bucephala albeola) predominantly nest in the boreal forests and aspen parklands of Canada and Alaska. Historically, Buffleheads were common migrants but not summer residents in Minnesota. However, recent observations in Minnesota and surrounding states suggest increased breeding activity in the region. In 1978, the first Bufflehead brood in Minnesota was recorded at East Park Wildlife Management Area. Annually, Agassiz National Wildlife Refuge (NWR) has conducted pair and brood surveys, with species-specific records available from 1990 to 2014. We report an increase in numbers of Bufflehead breeding pairs and broods at Agassiz NWR and new pair observations in surrounding areas.

Detecting early warning signals of tree mortality in boreal North America using multiscale satellite data.

Increasing tree mortality from global change drivers such as drought and biotic infestations is a widespread phenomenon, including in the boreal zone where climate changes and feedbacks to the Earth system are relatively large. Despite the importance for science and management communities, our ability to forecast tree mortality at landscape to continental scales is limited. However, two independent information streams have the potential to inform and improve mortality forecasts: repeat forest inventories and satellite remote sensing. Time series of tree-level growth patterns indicate that productivity declines and related temporal dynamics often precede mortality years to decades before death. Plot-level productivity, in turn, has been related to satellite-based indices such as the Normalized difference vegetation index (NDVI). Here we link these two data sources to show that early warning signals of mortality are evident in several NDVI-based metrics up to 24years before death. We focus on two repeat forest inventories and three NDVI products across western boreal North America where productivity and mortality dynamics are influenced by periodic drought. These data sources capture a range of forest conditions and spatial resolution to highlight the sensitivity and limitations of our approach. Overall, results indicate potential to use satellite NDVI for early warning signals of mortality. Relationships are broadly consistent across inventories, species, and spatial resolutions, although the utility of coarse-scale imagery in the heterogeneous aspen parkland was limited. Longer-term NDVI data and annually remeasured sites with high mortality levels generate the strongest signals, although we still found robust relationships at sites remeasured at a typical 5 year frequency. The approach and relationships developed here can be used as a basis for improving forest mortality models and monitoring systems.

Tackling rarity and sample bias with large-scale biodiversity monitoring: a case study examining the status, distribution and ecology of the lichen Cladonia rei in Alberta, Canada

AbstractSpecies conservation depends on accurate data, but for many lichens existing collections are geographically biased and contain many taxonomic errors. It is unclear whether ‘non-expert’, systematic monitoring schemes can address these sources of error, particularly for taxonomically challenging lichens (e.g. species requiring chemistry for accurate identification). In this case study we use the Alberta Biodiversity Monitoring Institute (ABMI), a large-scale, systematic, multi-taxon monitoring programme, to better understand the ecology and distribution of a putative rare species, Cladonia rei. Collections of C. rei from Alberta dating from 1947 suggested the species was broadly distributed but rare, with seven accessioned specimens. We used comparative morphology, thin-layer chromatography and habitat modelling to compare historical records against more recent material from ABMI surveys. Contrary to the historical collections, ABMI samples suggest C. rei is almost entirely limited to the dry mixed grassland, northern fescue grassland and aspen parkland natural regions, and that within these ecosystems it is relatively common. The typical ecotype exhibited included a persistent primary thallus, podetia with a persistent basal cortex, and secondary squamules; typically they lacked cups, well-developed apothecia and fumarprotocetraric acid, and ramifications were sparse. Cladonia rei was consistently found in pastures and undisturbed grasslands that hosted relatively rich communities of epigeic lichens, thus it does not appear to act as a pioneer in Alberta or to commonly occupy the anthropogenic niches documented elsewhere. In summary, large-scale, systematic, non-targeted monitoring employing novices redressed issues of sample bias through almost 300 C. rei collections, simultaneously improving the ecological understanding of a putative rare species.

Flea beetle (Coleoptera: Chrysomelidae) species in canola (Brassicaceae) on the northern Great Plains of North America

AbstractFlea beetle (Coleoptera: Chrysomelidae) species and numbers were determined from yellow sticky traps (n=11 180) set out in canola (Brassica Linnaeus, Brassicaceae) fields at 300 site years and 15 ecoregions across the Canadian Prairie provinces in each spring of 2007–2011 and in North Dakota, United States of America in 2010–2011. Peak numbers and relative species abundance varied with year, site, and ecoregion. Phyllotreta striolata (Fabricius) was most common in northern ecoregions, whereas Phyllotreta cruciferae (Goeze) dominated nearer the 49th parallel. The proportion of P. striolata in northern areas increased dramatically compared with surveys in the 1970s. Phyllotreta striolata displaced Psylliodes punctulata Melsheimer as the most common flea beetle in the Peace River Lowlands, displaced P. cruciferae as the most common flea beetle in the Aspen Parkland of central Alberta, Canada, and increased in proportion in central Saskatchewan and much of Manitoba, Canada. Once rare in southern ecoregions, P. striolata was found there in increasing numbers. Temperature was the most consistent weather parameter to predict occurrence of both P. cruciferae and P. striolata. Although P. striolata became more numerous over years in four of seven principal ecoregions, P. cruciferae remained the predominant species on traps with the highest numbers of flea beetles.