Prairie Landscape Research Articles

Introduction to the Compositae of the North American Prairies

SummaryThe North American Prairie landscape at the Royal Botanic Gardens, Kew at Wakehurst Place, Ardingly, West Sussex, is discussed. The abundance of the Compositae in the North American Prairies is outlined, by tribe, and comments provided on a range of 105 interesting Compositae that could be considered in prairie plantings, for dry, moist and wet situations. The exclusion of a number of plants that are most unsuitable for prairie plantings is also covered, with whole tribes, such as the Cardueae and Anthemideae, excluded from potential planting schemes, and a limited selection made from the Lactuceae and Senecioneae. The Astereae, other than providing a large selection of potential prairie plants, is discussed more fully, especially with the break‐up of the core genus Aster. Both inside and outside of the prairie environment there have been many taxonomic changes, with name changes of concern to taxonomists and horticulturists alike. Shaw's list is revised, relevant to those he left in Aster, and some observations made on how the splitting of Aster is still an active area of research. The differing propagation methods, in general and for the Compositae in particular, are outlined, covering vegetative propagation methods, and seed harvesting, cleaning, and sowing preparation techniques outlined. A number of previously published plates from Curtis's Botanical Magazine are used to illustrate some of the tribes, and are supplemented by photographs of several species, mostly from the Heliantheae, in cultivation at the Royal Botanic Gardens, Kew. The supportive appendices cover: Appendix 1 – 105 suitable Compositae that can be considered for prairie plantings, each with an indication of tribe, common name/s, publication details of those previously illustrated in Curtis's Botanical Magazine (or in this issue), the plate number under which it was published, together with those republished in this issue, and photographs of a handful of others, together with an indication of the base colour/s of the flowering capitula of each, and Appendix 2 an updated list of the species left in Aster in Shaw's 2014 list following several subsequent transfers into other genera, and a different view of the taxonomy of some of the genera.

Direct and indirect landscape-scale pathways structure carnivore communities in an agro-prairie ecosystem

Abstract Many carnivore populations have experienced substantial declines and are at increased risk of extinction, mainly due to negative interactions with humans and biological traits that make them susceptible to habitat loss and fragmentation, often driven by agricultural expansion. Carnivore community richness is likely influenced by many direct and indirect factors, though it is unclear how carnivore communities are structured in prairie landscapes that are considered one of the most imperiled ecosystems worldwide. Our goal was to identify landscape-scale effects driving carnivore community richness in a contemporary agro-prairie ecosystem. We used 3 years of presence data (2018–2020) from camera-trap sites (n = 381) distributed across western Kansas, United States and developed a structural equation model (SEM) to test a priori hypotheses explaining carnivore richness. Measures of water availability, native prairie, and agriculture—as well as sampling effort (i.e., days cameras were active)—were all positively associated with carnivore richness. Additionally, our index of rabbit abundances at sites had a direct positive effect on our measure of carnivore richness. Our SEM explained 42% of the variance in carnivore richness (χ2 = 8.76, d.f. = 21, P = 0.99) in this human-dominated landscape. Our results suggest that carnivore communities in agro-prairie landscapes are structured through multiple direct and indirect landscape-scale pathways. Contemporary agro-prairie mosaics may act as filters for the agricultural tolerance of carnivores, with species more vulnerable to native prairie loss becoming locally extirpated.

Drought Stress Responses of Some Prairie Landscape C4 Grass Species for Xeric Urban Applications

Creating xeric landscapes in lawns and prairies is a significant challenge and practical need in arid urban environments. This study examined the drought resistance of some C4 grass species for constructing urban lawns and prairies. A factorial experiment based on randomized complete block designs with four replications was conducted. Experimental treatments were two irrigation levels (100% and 50% Field Capacity (FC)) and five warm-season grass species (Andropogon gerardii Vitman, Sorghastrum nutans (L.) Nash, Panicum virgatum L., Schizachyrium scoparium (Michx.) Nash, and Bouteloua curtipendula (Michx.) Torr.). The effects of drought on physiological, morphological, and qualitative characteristics of the grass species were analyzed. Drought conditions induced a decrease in all the measured traits. However, fewer physiological, morphological, and qualitative characteristics were affected by drought stress on Andropogon gerardii, Schizachyrium scoparium, and Bouteloua curtipendula, compared to the other two species. Overall, warm-season grasses of Andropogon gerardii, Schizachyrium scoparium, and Bouteloua curtipendula, had greater adaptability to drought stress, making them promising C4 grass species for prairie or lawn landscaping in arid urban environments. Landscape professionals and decision-makers should consider using Andropogon gerardii, Schizachyrium scoparium, and Bouteloua curtipendula, as these were the most resilient grass species for drought-tolerant prairie landscaping schemes. Sorghastrum nutans and Panicum virgatum may be used as a second priority if a more diverse variety of grasses is required for drought-resilient prairie or lawn landscaping in arid cities.

Inoculum dose-disease response relationships for the pea root rot pathogen, Aphanomyces euteiches, are dependent on soil type and other pathogens.

The oomycete pathogen, Aphanomyces euteiches, was implicated for the first time in pea and lentil root rot in Saskatchewan and Alberta in 2012 and 2013. Subsequent surveys from 2014 to 2017 revealed that Aphanomyces root rot (ARR) was widespread across the Canadian prairies. The absence of effective chemical, biological, and cultural controls and lack of genetic resistance leave only one management option: avoidance. The objectives of this study were to relate oospore levels in autoclaved and non-autoclaved soils to ARR severity across soil types from the vast prairie landscape and to determine the relationship of measured DNA quantity of A. euteiches using droplet digital PCR or quantitative PCR to the initial oospore inoculum dose in soils. These objectives support a future end goal of creating a rapid assessment method capable of categorizing root rot risk in field soil samples to aid producers with pulse crop field selection decisions. The ARR severity to oospore dose relationship was statistically significantly affected by the soil type and location from which soils were collected and did not show a linear relationship. For most soil types, ARR did not develop at oospore levels below 100/g soil, but severity rose above this level, confirming a threshold level of 100 oospores/g soil for disease development. For most soil types, ARR severity was significantly higher in non-autoclaved compared to autoclaved treatments, demonstrating the role that other pathogens play in increasing disease severity. There was a significant linear relationship between DNA concentrations measured in soil and oospore inoculum concentration, although the strength of the relationship was better for some soil types, and in some soil types, DNA measurement results underestimated the number of oospores. This research is important for developing a root rot risk assessment system for the Canadian prairies based on soil inoculum quantification, following field validation of soil quantification and relationship to root rot disease severity.

Spatiotemporal distributions of mammals occurring in an agro-prairie ecosystem.

Anthropogenic activities since the European colonization of the North American Great Plains have drastically altered landscape composition and configuration, subsequently affecting native biodiversity. These contemporary human-modified landscapes may affect mammal species' distributions, diel activity patterns, habitat use, and interspecific interactions, though a better understanding of these effects on mammals occurring in remaining prairie landscapes is needed. To fill this gap, we surveyed 381 randomly selected sites in 2018, 2019, and 2020 using motion-sensing camera traps across the western part of the US state of Kansas (7,160,077 ha). Sites were separated by ≥2 km ( = 8.16 km, SD = 3.61), and cameras were secured to a metal post 40 cm above ground and randomly oriented toward the north or south. We placed an olfactory attractant (mixture of skunk essence and petroleum jelly) on a wooden stake 3 m in front of each camera. Cameras were in place at each site for 28 consecutive days for each year. We manually identified all mammal species detected at each site, collating these data into a database that included taxonomic information for 14 families of mammals (Antilocapridae, Bovidae, Canidae, Cervidae, Cricetidae, Dasypodidae, Didelphidae, Erethizontidae, Felidae, Heteromyidae, Leporidae, Mephitidae, Mustelidae, Procyonidae, Sciuridae, and Muridae) comprising 28 total species. We recorded 31,178 mammal photographs (nonindependent events) over 27,954 camera trap nights during 2018 (n = 10,351), 2019 (n = 9478), and 2020 (n = 8125). Additionally, we included the time and date of each photocapture. Moreover, we gathered survey-specific data useful for modeling species-specific detection along with site-level habitat composition data taken at each site each year. These data will be useful for examining habitat use, species distributions, diel activity patterns, and spatiotemporal interactions between species and across guilds of mammals occurring in a rapidly changing agro-prairie ecosystem. There are no copyright restrictions, but we ask researchers to cite this paper when using these data for publication.

Freedom on the Frontier: Sharon Butala’s Novel <i>Wild Rose</i> as Existential Autofiction

In Wild Rose (2015), the seventh novel by Canadian prairie author Sharon Butala, the protagonist—young wife and aspiring homesteader Sophie Hippolyte—expresses profound anguish, rejection of upbringing and religion, and headstrong desire to remake herself on the prairie frontier of southwestern Saskatchewan in the mid-1880s. The novel marks a turn in Butala’s fiction toward atheistic existential philosophy, a progression from a questioning to a rejection of organized religion and an emphasis on complete freedom. This turn was prompted by her suffering and questioning as Butala dealt with the rather sudden death of her husband, the loss of her way of life on, and intimate connection with, the prairie landscape, and the need to remake herself. Indeed, Wild Rose can be considered “existential autofiction” in which Butala fictionalizes her experience of loss and her rejection of religion (specifically Catholicism) via Sophie, one of her most resilient characters, who seeks freedom on the frontier.

Divergent responses of butterflies and bees to burning and grazing management in tallgrass prairies.

Butterflies and bees contribute significantly to grassland biodiversity and play important roles as pollinators and herbivores. Grassland conservation and management must be seen through the lens of insect conservation and management if these species are to thrive. In North America, grasslands are a product of climate and natural disturbances such as fire and grazing. These natural disturbances have changed considerably since European colonization and subsequent landscape fragmentation. The aim of this study was to better understand the impacts of fire and grazing management on butterfly and bee communities in tallgrass prairie, enabling land managers and conservationists to better protect and manage remnant prairie. We examined butterfly and bee abundance, species richness, and diversity in Minnesota tallgrass prairies managed by grazing or fire. In 2016 and 2017, we surveyed butterflies, bees, vegetation, and surrounding land use at 20 remnant prairies (10 burned and 10 grazed) with known management histories. Butterfly and bee abundance at our study sites were significantly negatively correlated. Butterfly abundance, but not species richness, was higher in burned than grazed prairies, and prairie-associated grass-feeding butterflies were more abundant at sites with higher plant species richness. Bee abundance was unrelated to management type but was higher at sites with sandier soils; bee species richness was positively associated with forb frequency. These findings highlight the challenges of designing management plans tailored to wide groups of pollinators and the potential pitfalls of using one group of pollinators as indicators for another. They also point to the importance of a mosaic of management practices across the prairie landscape.

Access to prairie pollen affects honey bee queen fecundity in the field and lab

Beekeepers experience high annual losses of colonies, with environmental stressors like pathogens, reduced forage, and pesticides as contributors. Some factors, like nutritional stress from reduced flower abundance or diversity, are more pronounced in agricultural landscapes where extensive farming limits pollen availability. In addition to affecting other aspects of colony health, quantity and quality of pollen available are important for colony brood production and likely for queen egg laying. While some US beekeepers report >50% of colony loss due to queen failure, the causes of poor-quality queens are poorly understood. Access to resources from native prairie habitat is suggested as a valuable late-season resource for honey bees that can reverse colony growth declines, but it is not clear how prairie forage influences queen egg laying. We hypothesized that the pollen resources present in an extensive Midwestern corn/soybean agroecosystem during the critical late season period affect honey bee queen egg laying and that access to native prairies can increase queen productivity. To test this, we designed a field experiment in Iowa, keeping colonies in either soybean or prairie landscapes during a critical period of forage dearth, and we quantified queen egg laying as well as pollen collection (quantity and species). Then, using pollen collected in the field experiments, we created representative dietary mixtures, which we fed to bees using highly controlled laboratory cages to test how consumption of these diets affected the egg laying of naive queens. In two out of three years, queens in prairies laid more eggs compared to those in soybean fields. Pollen quantity did not vary between the two landscapes, but composition of species did, and was primarily driven by collection of evening primrose (Oenothera biennis). When pollen representative of the two landscapes was fed to caged bees in the laboratory queens fed prairie pollen laid more eggs, suggesting that pollen from this landscape plays an important role in queen productivity. More work is needed to tease apart the drivers of these differences, but understanding how egg laying is regulated is useful for designing landscapes for sustainable pollinator management and can inform feeding regimes for beekeepers.

Our Language is From the Land: niinyanaan nutr piyii la laange

This article documents how my cultural identity as a Métis woman is inherently linked to Michif words and phrases that originate from the land. Through the Michif language I continue to situate myself directly on the Saskatchewan prairie landscape. And it is because of the collective efforts of Michif speakers and Métis Old Ones who work tirelessly toward the rejuvenation of Michif language that I have been led toward working within the healing landscape which I now occupy. Keywords: Métis land claim, Métis rights, Métis self-government, Métis Nation

Predictive Mapping of Low-Density Juniper Stands in Prairie Landscapes of the Northern Great Plains

Expanding distributions of native juniper species have had significant ecological and economic impacts on prairie ecosystems of the Great Plains. Juniper encroachment reduces rangeland production by decreasing herbaceous biomass and affecting natural ecosystem functions as it alters other native plant communities, microclimates, and soils. Juniper distribution maps are needed to support proactive management, but they often underestimate the extent of low-density juniper stands. Our objectives were to extend a previous juniper mapping study by 1) fitting a predictive ecological model for low-density (< 15% fractional cover) juniper stands and assessing the classification accuracy, 2) determining the habitat variables that had the strongest associations with low-density juniper, and 3) applying the model to map low-density juniper stands, where proactive management has the greatest potential for stopping further juniper encroachment. The study area included counties bordering the Missouri River in southeastern South Dakota and northeastern Nebraska covering approximately 23 000 km2. Environmental predictors included seed source distance and density, as well as topography, climate, soils, and land use variables. Areas of low-density juniper were identified by visual interpretation of sample plots from digital aerial photography. We used a machine-learning approach to classify low-density juniper with the random forests algorithm. Model accuracy was high with an area under the receiver operating characteristic curve of 0.884. Variables related to seed sources were the most important predictors, and precipitation, slope angle, and the local intensity of human land use also had substantial influences. A previous map based on Landsat imagery identified 209 968 acres (84 971 ha) as juniper with in the study area, and this study found an additional 430 648 acres (174 277 ha) classified as low-density juniper stands. These results can provide agencies and land managers with more accurate information about the distribution of juniper, and the underlying techniques can be extended to map woody plant encroachment in other areas.

Spatial ecology of female bighorn sheep in a prairie landscape in Nebraska

AbstractUnderstanding the spatial ecology of small populations at the periphery of their range is important for identifying factors limiting population growth and developing sound management strategies. Bighorn sheep were reintroduced to Nebraska in 1981 and persist in a small population at the easternmost extent of the distribution of the species, where 1 of the 2 subpopulations is declining. Bighorn sheep space use and movement has been studied extensively in mountain and desert populations, but information is sparse from prairie populations in the Northern Great Plains. We investigated the spatial ecology of female bighorn sheep in Nebraska, USA, with global positioning system (GPS) telemetry. We tested the hypothesis that space use and movements would vary across seasons, years, and individuals but predicted that migration would involve relatively short distances in this translocated population (relative to native populations) occupying a fragmented landscape. Overall, females used smaller seasonal home ranges (3.3–7.8 km2) than most of those reported previously for the species and exhibited a high degree of variability in space use and movements across seasons, subpopulations, and individuals. Most females (92–100%) exhibited fidelity to their home ranges across seasons and years. Six females migrated between spatially distinct core lambing and winter ranges, although the distances (range = 7.9–8.7 km) and mean elevations (range = 31–41 m) between these core seasonal ranges were less than those reported for most native, migratory bighorn sheep populations. After accounting for variation in season, subpopulation, and years, home range size was positively associated with road density in both subpopulations (P &lt; 0.001), suggesting that females incur greater energetic costs associated with greater space use in areas of higher fragmentation. Our results establish the basic spatial ecology of female bighorn sheep in Nebraska where their behavior appears to reflect the isolated nature of suitable habitat in this fragmented prairie landscape.

Seasonal, Landscape, and Attractant Effects on Lesser Grain Borer, Rhyzopertha dominica (F.), Captures in Northeast Kansas

The lesser grain borer, Rhyzopertha dominica (F.), is a highly diverse feeder and widely distributed throughout the United States in agricultural and non-agricultural landscapes. Six four-funnel Lindgren traps were deployed in feed mill, grain elevator, and native prairie landscapes, to determine the most attractive food and pheromone combination (attractant) and patterns in seasonal captures. Traps were baited with combinations of wheat (crimped, high moisture, pre-fed) with or without an R. dominica specific aggregation pheromone in 2017 and 2018. Traps were deployed for 48 h, collected, and the number of R. dominica counted. Rhyzopertha dominica was captured among all landscapes with all attractants. There was a significant correlation between temperature and R. dominica captures, with peak captures occurring during the warmest months. Significantly more R. dominica adults were captured in traps containing the pheromone. In 2017, pheromone traps captured 818% more R. dominica and 543% more than in 2018. The pheromone component in the trap was more attractive than any natural stored wheat condition and should be included in future studies. Understanding the seasonal patterns and changes in capture rates in agricultural and non-agricultural landscapes may be useful in determining times of increased immigration pressure into the newly harvested grain.

Future Shift for ‘Big Things’: From Starchitecture via Agritecture to Parkitecture

This article analyses three recent shifts in what called the geography of ‘Big Things’, meaning the contemporary functions and adaptability of modern city centre architecture. We periodise the three styles conventionally into the fashionable ‘Starchitecture’ of the 1990s, the repurposed ‘Agritecture’ of the 2000s and the parodising ‘Parkitecture’ of the 2010s. Starchitecture was the form of new architecture coinciding with the rise of neo-liberalism in its brief era of global urban competitiveness prevalent in the 1990s. After the Great Financial Crash of 2007–2008, the market for high-rise emblems of iconic, thrusting, skyscrapers and giant downtown and suburban shopping malls waned and online shopping and working from home destroyed the main rental values of the CBD. In some illustrious cases, ‘Agritecture’ caused re-purposed office blocks and other CBD accompaniments to be re-purposed as settings for high-rise urban farming, especially aquaponics and hydroponic horticulture. Now, COVID-19 has further undermined traditional CBD property markets, causing some administrations to decide to bulldoze their ‘deadmalls’ and replace them with urban prairie landscapes, inviting the designation ‘Parkitecture’ for the bucolic results. This paper presents an account of these transitions with reference to questions raised by urban cultural scholars such as Jane M. Jacobs and Jean Gottmann to figure out answers in time and space to questions their work poses.

The local responses of aquatic ecosystems to adjacent grassland conservation: Can streams of dreams exist in a degraded riverscape?

Abstract Landscape homogenization and the removal of riparian areas have altered stream ecosystems worldwide. Numerous conservation programmes attempt to improve water quality and increase instream habitat heterogeneity to elicit desired biological responses. However, the effectiveness of many conservation efforts on isolated stream fragments remains unknown, especially in grassland regions. The effects of grassland conservation practices and the re‐establishment of riparian corridors in the James River basin, South Dakota (USA) on stream water quality, habitat availability and aquatic macroinvertebrate and fish assemblages were studied in an agriculturally dominated prairie landscape. Grassland conservation efforts may have repaired riparian condition, reduced turbidity and created more diverse instream habitat complexes at conservation sites based on comparisons with paired reference reaches. Reference sites were relatively homogeneous, with prevalent siltation, bank erosion and disturbances to the riparian vegetation. Owing to significant riparian vegetation development, overhanging and aquatic vegetation, benthic detritus and woody materials were significantly more common at conservation reaches. Restoration efforts that assume ‘if you (re‐)build it, they will come’ (i.e. the ‘field of dreams’ hypothesis) underestimate other important barriers to biodiversity restoration in dynamic, grassland riverscapes. Although aquatic organisms in grassland ecosystems are adapted to rapidly inhabit available habitats, the development of niche space at conservation reaches did not directly result in colonization by aquatic life. Grassland management actions did not address stream connectivity issues or overcome land use influences elsewhere in the riverscape that may govern the responses of aquatic macroinvertebrates and fish. Stream fragmentation and continuing, damaging land use patterns seemed to exceed the positive effects of restoring isolated stream reaches in these heavily degraded catchments. Catchment‐scale management strategies that combine reach‐level restoration actions with efforts to improve connectivity are likely to be more successful in degraded riverscapes.

Mapping the Relative Habitat Quality Values for the Burrowing Owls (Athene cunicularia) of the Canadian Prairies Using an Innovative Parameterization Approach in the InVEST HQ Module.

The range and population of Burrowing Owls (BOs) are declining in the Canadian Prairies. Multiple anthropogenic sources of degradation (threat) are attributed to this trend. Yet, the cumulative degradation caused by these sources has not been quantified across this landscape. Using the InVEST Habitat Quality (HQ) module and a novel approach to parameterize the relative sensitivity scores in this framework, we quantified, mapped, and evaluated the relative HQ values for these species in the prairies. The results illustrate significant differences in the HQ values between the current range and areas within the historical range of these species that do not spatially intersect with their current spatial extent. However, the variations of HQ values are not statistically significant under the different spatial scenarios considered across the current breeding grounds. Nevertheless, the results within the specific land use/cover categories illustrate meaningful variations in the HQ values across the current range of these species. Our findings suggest that the existing declining trends could only be attributed to the synergistic impact of the considered threats and other factors undermining the essential ecological processes for these birds. The results also highlight the importance of expanding the spatial extent of the existing conservation measures to prevent further loss of these charismatic migratory birds from the prairie landscape. A good starting point is to consider the HQ change index, a measure defined to illustrate the relative habitat degradation under different sources of degradation. Further studies are still required to determine the spatiotemporal impacts of all sources of degradation on the habitat of these endangered species in Canada and across their global range.

Pre-fledging quality and recruitment in an aerial insectivore reflect dynamics of insects, wetlands and climate.

Wetland systems, including shallow palustrine ponds, are hotspots for emergent aquatic insects but are globally threatened by land-use practices and climate change. Loss of insects is hypothesized as a key driver of population declines in aerial insectivores, but studies of climate-driven fluctuations in pond abundance during wet-dry periods and aerial insects on nestling quality and apparent recruitment are lacking. Using tree swallow (Tachycineta bicolor) data spanning 14-28years we evaluated: (1) whether nestling quality based on pre-fledging (~ 12days old) body mass changed over the time series; (2) how annual estimates of aerial insect biomass and variability, temperature, and pond abundance influenced nestling mass; and (3) whether the annual number of recruits produced was related to the annual mean mass of nestlings, aerial insects, and pond abundance in their year of hatching. Average nestling body mass varied annually but no long-term temporal trends were detected. Nestlings were heavier when raised during periods of stable insect biomass, warmer temperatures, and higher pond abundance. Pond abundance consistently had strong effects on nestling mass and inter-annual apparent recruitment, suggesting that this metric provides a complementary index of either higher prey abundance or higher-quality aquatic prey. Overall, pre-fledging quality and annual recruitment of nestling tree swallows reflects dynamic interannualchanges in climate, pond availability, and aerial insect food supply. Our findings further suggest the abundance of ponds in this semi-arid prairie landscape is likely a strong predictor of regional population stability in tree swallows and possibly other ecologically similar species.

Restorative recreation: One landowner's experience restoring a cedar‐infested native prairie remnant in Iowa's Loess Hills

Abstract Over 80% of pre‐settlement Iowa was a prairie landscape, but conversion and neglect has reduced that to less than 0.1% of the original 30 million acres (12 million hectares). Much of the remaining remnant prairie lies within the Loess Hills landform in western Iowa. Here I describe my experience as a landowner identifying and restoring a native Loess Hills prairie remnant overtaken by Eastern redcedar (Juniperus virginiana). Archived aerial photographs confirm its native remnant status and have been used to monitor restoration progress. Both shearing and hand clearing of cedars have been undertaken at this site, providing an opportunity to compare patterns of ecosystem recovery within one remnant prairie. I find that cedar shearing, though effective at rapidly clearing a large swath of land, was associated with greater abundance of weedy and woody species compared to hand clearing that occurred more gradually over a longer period of time. However, consistent, targeted herbicide application to woody growth, as well as two prescribed fires, have led to good recovery and stabilization of the grassland with minimal annual recruitment of new brush. Photographs of faunal associations with Pasque flowers (Anemone patens) provide an indicator of the biodiversity on this prairie and suggest Pasque flowers, due to their abundance at this site, function as a keystone species that drives early spring ecosystem productivity. Based on my experience, I introduce a paradigm called restorative recreation to provide a framework for integrating ecosystem restoration activities with outdoor recreation to maximize benefits to personal health and well‐being, while improving the landscape for other species that share our common home.

Where Have the Native Grasses Gone?: What a Long-Term, Repeat Study Can Tell Us about California’s Native Prairie Landscapes

Much of the foothill and valley areas of coastal southern California are covered by stands of non-native grasses with occasional scattered patches of native bunch grasses. For decades, the dominant view held that these native bunchgrasses, particularly Stipa pulchra, once covered these lands and that grazing practices were a key cause of their decline. The so-called bunchgrass dominant paradigm (BDP) put forth by Clements influenced thinking on grassland ecology and biogeography for decades until it was discredited. Recent research suggests that grazing and related disturbances might have supported native bunchgrasses, but results are mixed and most studies cover only a short time frame. This research uses a long-term, repeat study design to analyze and compare data from three surveys of 15 permanent quadrats in La Jolla Valley, California, to determine changes in grassland cover over 34 years. A unique aspect of the study is that the site was selected by researchers precisely because it contained excellent ‘relic’ stands of Stipa pulchra (in accordance with the BDP) and the baseline study was conducted shortly after the area was released from grazing and placed under conservation management. We compared data on species frequency and percent cover collected using the same sampling routine for three periods: 1981, 1994, and 2015, to document the shifts in vegetation. We found that native grass cover decreased dramatically (especially on the valley floor), exotic grass cover fluctuated widely over time, while both native and exotic forb cover increased over time. The findings support the notion that prior grazing management practices may have supported the former stands of Stipa pulchra.

Application of dynamic contributing area for modelling the hydrologic response of the Assiniboine River Basin to a changing climate

The Prairie landscape consists of numerous pothole depressions which produce complex fill-and-spill runoff generation processes that result in intermittent hydrologic connectivity and dynamic contributing areas (DCA). We investigated the effect of including DCA in the modified version of the Soil and Water Assessment Tool (SWAT) model and its implication on future streamflow projection for the pothole dominated Assiniboine River Basin (ARB). The fill-and-spill processes that lead to DCA were captured using a physically-based approach, with a volumetric threshold to reduce the computational demand. Despite the challenges in accurately simulating prairie pothole hydrology, both in terms of timing and volume of runoff, the modified approach improved streamflow modelling performance, and reduced model uncertainty. Further, we evaluated the effects of representing DCA on projecting future streamflow by using eight statistically downscaled CMIP5 GCMs, forced with the RCP4.5 and RCP8.5 scenarios. End of century projections indicate increases in annual precipitation and temperature across the ARB, with decreasing summer precipitation relative to the 1976–2005 baseline period. Compared to the standard SWAT setup that does not allow for DCA, the modified model was found to be more responsive to climatic change with relatively larger projected increases in seasonal and annual flows at the majority of evaluated stations. This advance in DCA modelling will facilitate longer-term large basin-scale simulations that are more representative for the Prairie region.

A social-ecological systems approach for the assessment of ecosystem services from beef production in the Canadian prairie

Producing food to meet rising global demand requires a more thorough understanding of how farming systems can ensure food security without compromising economic, environmental, and social sustainability. This dilemma can be addressed through a social-ecological systems approach to ecosystem service assessment, which assesses the linkages between the different components of an agricultural social-ecological system – beef production in the Canadian Prairies. Using this framework, we documented the relationships between governance and management, social and ecological structures and processes, ecosystem services and human well-being for these systems. We also examined how this framework could aid in the greater integration of ecosystem services into decision-making and management practices for these systems. The framework was applied to all stages of the prairie beef production cycle, consisting of the cow-calf, backgrounding, finishing and feed production stages. The benefits, shortcomings and limitations of such an approach as well as the state of knowledge on relationships between the components of the system are discussed, and recommendations for future research directions, farm management strategies and policy are proposed. Overall, the high degree of heterogeneity in biophysical and socio-economic conditions across the prairie landscape underscores the need for more site-specific ecosystem service assessments and environmental stewardship policies that are tailored to these specific contexts.