Festuca Campestris Research Articles

Spotted knapweed (Centaurea stoebe) creates a soil legacy effect by modulating soil elemental composition in a semi-arid grassland ecosystem.

Invasive plants such as spotted knapweed (Centaurea stoebe) are particularly detrimental to fragile ecosystems like semi-arid grasslands in the interior British Columbia, impacting aboveground and belowground ecology. Physical removal of C. stoebe has been one of the most popular invasive species management strategies, but the impact of C. stoebe removal on soil has hardly been studied. Here, we examine the legacy effect of C. stoebe on soil elemental composition and ecosystem function following its removal in the Lac Du Bios Grasslands Protected Area, British Columbia. First, we selected 40 paired C. stoebe invaded and control (uninvaded) plots and removed all vegetation from these plots. We planted Festuca campestris seedlings in these plots and harvested and weighed the biomass after four months. Additionally, we quantified total carbon and nitrogen in soil. We observed that C. stoebe invaded plots had significantly lower F. campestris biomass. Moreover, the total carbon and nitrogen content, and carbon/nitrogen ratio were significantly lower in C. stoebe invaded plots. We further analyzed 12 common soil elements and found the elemental composition was significantly different in C. stoebe invaded plots compared to controls. We investigated the impact of elemental composition on soil ecosystem functions (such as total soil carbon, total soil nitrogen, and F. campestris productivity). Our analysis revealed significant relationships amongst the elemental composition and total soil carbon and nitrogen, and F. campestris productivity. The results indicate that C. stoebe exerts a legacy effect by altering the soil elemental composition that may subsequently impacts soil ecosystem functions such as plant productivity and total carbon and nitrogen content.

Semiarid bunchgrasses accumulate molybdenum on alkaline copper mine tailings: assessing phytostabilization in the greenhouse

Phytostabilization is the use of plants and soil amendments to physically stabilize and remediate contaminated mine wastes and to control wind and water erosion in semiarid environments. The aim of this study was to evaluate two native bunchgrass species’ (Pseudoroegneria spicata and Festuca campestris) biomass accumulation and metals uptake response to locally available soil amendments (compost, wood ash and wood chips) to determine their suitability for phytostabilization at an alkaline copper mine tailings site in British Columbia, Canada. In the greenhouse, bunchgrasses important as forage for livestock and wildlife were grown in tailings with various ash–compost–wood chip combinations and evaluated using a randomized complete block design with 13 treatments and 10 replicates. Plants were harvested after 90 d, and tissues were analyzed for root and shoot biomass. Tissue samples (n = 3) from three treatment subsets (ash, compost, blend) were selected for elemental analysis. Biomass increased with increasing compost applications, and the response was greatest for P. spicata. Shoot molybdenum exceeded the maximum tolerable level for cattle and was significantly higher when grasses were grown on the ash treatment (183–202 mg kg−1) compared to the others (19.7–58.3 mg kg−1). Translocation and root bioconcentration factors were highest on the ash treatment (2.53–12.5 and 1.75–7.96, respectively) compared to the other treatments (0.41–3.43 and 1.47–4.79, respectively) and indicate that both species are ‘accumulators.’ The findings suggest that these bunchgrasses were not ideal candidates for phytostabilization due to high shoot tissue molybdenum accumulation, but provide important considerations for mine restoration in semiarid grassland systems.

Grazing exclosures reveal divergent patterns of change in bunchgrass grasslands of Western Canada

Thirty-six long-term (14–83 years) cattle grazing exclosures and adjacent grazed pastures spanning a climatic gradient from cooler–wetter to warmer–drier growing seasons in south-central British Columbia were compared for temporal vegetation change. Trajectories of temporal vegetation change from non-metric multidimensional scaling were mostly scattered for the grazed areas, but more directed toward the dominant grasses, primarily rough fescue (Festuca campestris) or Kentucky bluegrass (Poa pratensis), for the exclosures. Plant community differences, detected only after 10 years of grazing exclusion, were primarily due to structural shifts in overall species cover related to growth increases of the dominant grasses inside exclosures. Species richness remained unchanged between the first and last sampling dates in both grazed areas and exclosures, with both treatments showing moderate degrees (15%–30%) of turnover in species composition. Shannon diversity declined in both treatments as a result of the structural changes in species cover. The results highlight the value of repeated monitoring of long-term exclosures for assessment of grassland resiliency to grazing. Further studies of the interaction of grazing and climate are needed for a more complete understanding of the ongoing vegetation change.

Rodent seed predators and a dominant grass competitor affect coexistence of co‐occurring forb species that vary in seed size

Abstract Propagule size and number often vary by several orders of magnitude among co‐occurring plant species. Explaining the maintenance of this variation and understanding how propagule size contributes to coexistence remain a central challenge for community ecologists. The dominant paradigm is that a competition–colonization trade‐off maintains interspecific variation in seed size, but empirical support is limited and other coexistence mechanisms, such as size‐dependent seed predation, have not been examined. We examined how seed size, fecundity, and other functional traits of 18 co‐occurring perennial forbs trade‐off with both vulnerability to rodent seed predation and competitive response to a community‐dominant perennial bunchgrass. We added seeds of these species to 1 m2 plots at 10 sites where we factorially manipulated rodent seed predation and competition from the community dominant, Festuca campestris. For a given plot, seeds of each species were added at densities that reflected the fecundity (i.e., per capita seed production) for each species. Moreover, we varied total seed density among plots by adding seeds at one of five relative densities (0, 0.25. 0.5, 1.0, and 1.5 times each species’ fecundity) to examine how fecundity affected overall recruitment for each species. There was a trade‐off between seed size and fecundity, as expected, but larger seed size was also associated with greater plant height, lower C/N ratios, and lower water use efficiency, suggesting that seed size represented a “resource acquisitive” trait syndrome (as quantified by trait principal component scores). In the field experiment, the suppressive effects of seed predation on seed recruitment rate increased with increasing seed size. In contrast, smaller seeded species with less resource‐acquisitive traits were more negatively affected by competition from F. campestris than were species with more resource acquisitive traits. Synthesis. While the competition–colonization trade‐off has been the predominant mechanism thought to maintain coexistence among species that vary in fecundity and seed size, our work suggests that susceptibility to rodent seed predation and competitive response to community dominants represent alternative mechanisms that can differentially influence plant recruitment of species based on their seed size and associated traits.

Festuca campestris density and defoliation regulate abundance of the rhizomatous grass Poa pratensis in a fallow field

AbstractInvasion by the rhizomatous grass Kentucky bluegrass (Poa pratensis) is a global phenomenon, including into foothills rough fescue (Festuca campestris) grasslands of southwestern Alberta, Canada. In order to better understand the competitive relationships between these species, we conducted a fallow field study where rough fescue bunchgrass tussocks were transplanted at one of three planting densities (15, 30, or 45 cm spacing), and then subject to various treatments in a factorial design, including one‐time intensive summer defoliation and seeding of bluegrass into adjacent bare soil. Rough fescue plants exhibited marked intraspecific competition, as high planting densities increased tussock mortality, while decreasing plant tiller counts and relative inflorescence production, together with plant and tiller‐specific mass. However, high densities of the bunchgrass also reduced the cover and biomass of encroaching bluegrass, coincidental with reduced resource (soil moisture and light) availability in mid‐summer. Although summer defoliation increased rough fescue tiller counts, this disturbance reduced plant and tiller mass, and also increased Kentucky bluegrass. We conclude that while high densities of nondefoliated stands of rough fescue may increase resistance to bluegrass encroachment, a reduction in either fescue plant density or vigor via defoliation can increase the risk of bluegrass invasion within northern temperate grassland.

Grazing and solar irradiance drive patterns of change in two grassland plant communities in southern British Columbia

We compared the recovery of two plant communities over 14 years following a switch from spring to fall grazing (G), and in ungrazed exclosures (UG), at six sites in Lac du Bois Grasslands Provincial Park, British Columbia. Both communities showed similar large increases in cover of their respective dominant grasses – rough fescue (Festuca campestris), and bluebunch wheatgrass (Pseudoroegneria spicata) – in both G and UG treatments. As expected, the more productive rough fescue community had higher amounts of soil polysaccharides, and total soil C and N. Repeated measures ANOVA indicated significant declines in species richness and Shannon diversity over time, especially in the ungrazed rough fescue community. Non-metric multidimensional scaling of species cover data showed continued divergence between communities, largely due to an increase in abundance of the two dominant grasses. Community differences were mainly determined by aspect and its impact on soil temperature and water content. We concluded that, from a management perspective, switching to light fall grazing was as effective as removing grazing to assist in recovery from previous overgrazing, and that the relationship of grazing combined with the fine-scale pattern of variable solar irradiance was responsible for the closely interspersed mosaic of the two grassland communities.

Long-term ungulate exclusion reduces fungal symbiont prevalence in native grasslands.

When symbionts are inherited by offspring, they can have substantial ecological and evolutionary consequences because they occur in all host life stages. Although natural frequencies of inherited symbionts are commonly <100%, few studies investigate the ecological drivers of variation in symbiont prevalence. In plants, inherited fungal endophytes can improve resistance to herbivory, growth under drought, and competitive ability. We evaluated whether native ungulate herbivory increased the prevalence of a fungal endophyte in the common, native bunchgrass, Festuca campestris (rough fescue, Poaceae). We used large-scale (1ha) and long-term (7-10year) fencing treatments to exclude native ungulates and recorded shifts in endophyte prevalence at the scale of plant populations and for individual plants. We characterized the fungal endophyte in F. campestris, Epichloë species FcaTG-1 (F. campestris taxonomic group1) for the first time. Under ungulate exclusion, endophyte prevalence was 19% lower in plant populations, 25% lower within plant individuals, and 39% lower in offspring (seeds) than in ungulate-exposed controls. Population-level endophyte frequencies were also negatively correlated with soil moisture across geographic sites. Observations of high within-plant variability in symbiont prevalence are novel for the Epichloë species, and contribute to a small, but growing, literature that documents phenotypic plasticity in plant-endophyte symbiota. Altogether, we show that native ungulates can be an important driver of symbiont prevalence in native plant populations, even in the absence of evidence for direct mechanisms of mammal deterrence. Understanding the ecological controls on symbiont prevalence could help to predict future shifts in grasslands that are dominated by Epichloë host plants.

Horse ranching increases biodiversity in a foothills parkland prairie in northern Kananaskis Country, western Alberta

Vascular plant biodiversity was evaluated in two adjacent sections of a continuous prairie glade. One section has been subject to moderate grazing by feral horses (Equus ferus caballus) in late summer and fall for the past 25 years, while the other has been protected. From 28 June to 2 July 2009, we recorded cover for all vascular plants present in ten 1-m2 quadrats along five transects in each section. We calculated biodiversity measures, including species richness, evenness, and Shannon-Wiener and Simpson’s diversity indexes. Horse grazing did not affect richness but significantly increased evenness. Grazing increased the Shannon-Wiener index, but did not affect the Simpson’s index. Cover and frequency values for most species differed significantly between the two sites. Mountain Rough Fescue (Festuca campestris Rydberg) dominated the non-grazed site but several shorter grasses and different forbs dominated the grazed site. The plant community in the grazed areas can be seen as an earlier seral stage of the fescue community with a different contingent of plant species. Light grazing in part of the prairie glade increased overall plant diversity so that it provided more diverse animal habitat.

Isolating the role of soil resources, defoliation, and interspecific competition on early establishment of the late successional bunchgrass Festuca campestris

Native grasslands are valued for biodiversity and supporting dormant season grazing, but are prone to invasion. In western Canada, revegetation of Festuca campestris grasslands may be hindered by Poa pratensis, an invasive grass. To determine the competitive interaction of these species during establishment, two greenhouse experiments were conducted where F. campestris seedlings were planted in monocultures or mixtures with P. pratensis. The first experiment used equal‐aged (3‐month old) seedlings of both species, while the second experiment used unequal‐aged seedlings (4‐month‐old F. campestris and 2‐month‐old P. pratensis). Seedling performance was measured in response to manipulations of water and nitrogen, defoliation, and plant neighbor. While water and nitrogen reduced the biomass and vegetative reproduction (tillering) of F. campestris, exposure to P. pratensis most strongly limited the growth of F. campestris seedlings regardless of other treatments. More frequent and consistent decreases in F. campestris due to P. pratensis were observed in older F. campestris seedlings than younger seedlings. Defoliation also reduced the growth of F. campestris, and the added presence of P. pratensis during defoliation further enhanced these reductions in younger, equal‐aged bunchgrass seedlings. Overall, these results suggest that when restoring native F. campestris grasslands, early establishment may be improved by reducing the negative impacts of P. pratensis, and avoiding severe defoliation.

Long-term grazing effects on rough fescue grassland soils in southern British Columbia

Krzic, M., Lamagna, S. F., Newman, R. F., Bradfield, G. and Wallace, B. M. 2014. Long-term grazing effects on rough fescue grassland soils in southern British Columbia. Can. J. Soil Sci. 94: 337–345. Rough fescue (Festuca campestris Rydb.) is a highly palatable forage species with little resistance to continuous grazing. The objective of this study was to evaluate the effects of long-term cattle grazing on soil properties, above-ground biomass, and canopy cover of key grass species on rough fescue grasslands in the southern interior British Columbia. Soil and vegetation properties were determined on a total of six open grassland sites located at the Lac du Bois and Hamilton Mountain. At all sites, grazing use has decreased over time, with the heaviest grazing occurring prior to 1960. The long-term (25–75 yr) elimination of grazing on these semi-arid grasslands has led to greater above-ground biomass and canopy cover of rough fescue, as well as increased soil polysaccharides; however, no differences in total soil C, N, and aggregate stability were found between pastures with and without grazing. Both soil bulk density and mechanical resistance were greater on grazed plots compared with those without grazing, with differences being more pronounced at the Hamilton Mountain location. The current grazing regime has not allowed for the elimination of negative effects of overgrazing on soil compaction on these rough fescue grasslands, especially at the location that continued to be grazed more heavily (i.e., Hamilton Mountain). Our findings suggest that soils in these grazing-sensitive grasslands need more than 75 yr to fully recover from the impacts of overgrazing.

Long-term grazing effects on rough fescue grassland soils in southern British Columbia

Krzic, M., Lamagna, S. F., Newman, R. F., Bradfield, G. and Wallace, B. M. 2014. Long-term grazing effects on rough fescue grassland soils in southern British Columbia. Can. J. Soil Sci. 94: 337-345. Rough fescue (Festuca campestris Rydb.) is a highly palatable forage species with little resistance to continuous grazing. The objective of this study was to evaluate the effects of long-term cattle grazing on soil properties, above-ground biomass, and canopy cover of key grass species on rough fescue grasslands in the southern interior British Columbia. Soil and vegetation properties were determined on a total of six open grassland sites located at the Lac du Bois and Hamilton Mountain. At all sites, grazing use has decreased over time, with the heaviest grazing occurring prior to 1960. The long-term (25-75 yr) elimination of grazing on these semi-arid grasslands has led to greater above-ground biomass and canopy cover of rough fescue, as well as increased soil polysaccharides; however, no differences in tot...

Effects of long-term protection from grazing on phenotypic expression in geographically separated mountain rough fescue populations

Thompson, D. J. and Willms, W. D. 2014. Effects of long-term protection from grazing on phenotypic expression in geographically separated mountain rough fescue populations. Can. J. Plant Sci. 94: 33–39. Whether or not long-term grazing or protection from grazing alters the genetic makeup of grass populations has been debated. Mountain rough fescue [(Festuca campestris (Rydb.)], which is highly sensitive to summer grazing, and becomes dominant in plant communities with long-term protection, was chosen to address this question. Plants from three geographic sites (Stavely in AB, Milroy in the Kootenay trench, BC and Goose Lake on the BC interior plateau) with divergent grazing histories were vegetatively propagated from tillers. Daughter plants were planted into two field nurseries (at Kamloops, BC, and Stavely, AB) and morphological measurements were taken in two field seasons post-establishment. Plants from all three populations were taller, flowered earlier, and were more productive at the Kamloops nursery site. Of the three geographic sources, plants from the Goose Lake site were most distinct with narrower leaves, later flowering, and greater yield. Plants with a long history of grazing had slightly shorter fertile tillers and leaves than plants with a history of long-term protection.

Impacts from Winter-Early Spring Elk Grazing in Foothills Rough Fescue Grassland

Foothills rough fescue (Festuca campestris) grasslands provide important foraging habitat for wildlife and livestock in the northwestern United States and southwestern Canada. Foothills rough fescue is sensitive to grazing during late spring —early summer but is believed to be more tolerant of grazing during winter—early spring. We evaluated vegetation and soil impacts from long-term winter—early spring grazing at 2 intensities (HG = heavy grazing, LG = light grazing). We studied a foothills rough fescue grassland in west central Montana, USA, that had been grazed almost exclusively by Rocky Mountain elk (Cervus elaphus nelsoni ) during winter—early spring for 58 years. Foothills rough fescue tolerated LG but not HG, whereas bluebunch wheatgrass (Pseudoroegneria spicata) and Idaho fescue (Festuca idahoensis) did not tolerate either LG or HG. Decreased productivity of foothills rough fescue in HG was accompanied by decreased herbaceous ground cover and increased abundance of the invasive dense clubmoss (Selaginella densa). Soil nutrient status (OM, C, N, C:N ratio) did not differ between HG and LG; however, soil bulk density was 18% greater in HG, and the Ah horizon was 20% thinner in HG. Overall, our results indicate that long-term elk grazing during winter—early spring degraded this terrestrial ecosystem, and we conclude that periodic rest from ungulate grazing during winter— early spring is necessary to sustain foothills rough fescue grasslands.

Forage Production Potential in a Ponderosa Pine Stand: Effects of Tree Spacing on Understorey Plants after 45 Years

We examined the development of understorey forage plant communities in relation to tree density in an experimental ponderosa pine (Pinus ponderosa) stand. We used a 45-year-old ponderosa pine spacing trial near Westwold, British Columbia, Canada, with five spacing treatments (1.22, 2.44, 3.66, 4.88, and 6.10 m) to sample understorey biomass and diversity, with a focus on pinegrass (Calamagrostis rubescens) and rough fescue (Festuca campestris)—two regionally important forage grasses. We predicted that there would be a positive correlation between tree spacing and understorey biomass and a compositional shift from pinegrass to rough fescue under increased tree spacing. We found that rough fescue, the preferred forage species, grew only under tree spacings equal to or greater than 3.66 m, with the greatest biomass at 4.88 and 6.10 m spacings, whereas pinegrass was equally abundant under all spacings. We believe that silvopasture principles could be applied to similar ponderosa pine stands to optimize and maintain both timber and forage productivity.

Responses of herbage and cattle tail switch hair δ15N value to long-term stocking rates on a rough fescue grassland

The purpose of this study was to investigate the response of δ15N in herbage and cattle tail switch hair to long-term grazing pressure on a rough fescue grassland (Festuca campestris Rydb.) near Stavely, Alberta, Canada. Cattle have grazed the paddocks from 15 May to 15 November annually since 1949. Stocking rates were 0, 2.4 and 4.8 animal unit months ha−1 for non-grazing (Control), moderate grazing (MG) and heavy grazing (HG), respectively. Green standing crop (GSC) was sampled monthly throughout the grazing season in 2007. The GSC was fractioned into neutral detergent fiber (NDF), acid detergent fiber (ADF), and their total nitrogen (TN) concentration and δ15N values in NDF, ADF and GSC were determined. Tail switch hair samples from cows (>2 years old) and calves (<1 year) were collected at the end of the grazing season in 2007 and 2008 and analysed for δ15N values. The TN concentrations in NDF and δ15N values in herbage NDF and ADF fractions were higher (P < 0.05) in MG and HG than the Control, and decreased over the grazing season. The δ15N values in tail hair also decreased (P < 0.05) over the grazing season but were not affected by grazing intensity. However, as expected, δ15N values in tail hair increased with herbage δ15N values. The δ15N values in tail hair were enriched by +5.2‰ compared to herbage δ15N values in 2007. Changes in δ15N value in GSC and cattle hair reflect the influence of grazing practices on N cycles through the animal/plant/soil system on this rough fescue grassland.

Changes in soil C, N, and P with long‐term (58 years) cattle grazing on rough fescue grassland

AbstractWe investigated soil response to long‐term cattle grazing at stocking rates 0 (CK), 2.4 (MG), and 4.8 (HG) animal unit months ha–1 on a Rough Fescue (Festuca campestris Rydb.) grassland. Soil organic C and N stocks and available nutrients were not affected by grazing while soil bulk densities (0–30 cm) were higher and P stocks (15–30 cm) were lower under grazing than CK. The slow rate change of soil C and N suggest the rich black grassland soils appear to tolerate intensive grazing.

Using three pairs of competitive indices to test for changes in plant competition under different resource and disturbance levels

Questions: How do different resource and disturbance levels interact to affect competition? How do different indices of competition change the interpretation of how competition changes under different resource and disturbance conditions? Location: Greenhouse, Thompson Rivers University, Kamloops, British Columbia, Canada. Methods: Three pairs of indices that have been used to differentiate the predictions of Grime (CSR) and Tilman’s (R) theories were used to assess competition on two species of temperate bunchgrass, (Pseudorogeneria spicata and Festuca campestris) grown in a greenhouse on stress and disturbance gradients. Stress was created by manipulating the amount of water (high, low) and concentration of nutrient solution (high, low) added to pots, while disturbance was created by clipping (clipped, unclipped) in a fully factorial design. Plants were grown individually or with a single neighbour. The three pairs of indices were: (1) absolute and relative competition; (2) competitive effect and response; and, (3) competitive importance and intensity. Results: Absolute competition and competitive importance were the only indices responsive to the resource gradient, which supports CSR theory, and also the only ones to record an effect of disturbance on the strength of competition – under high resource conditions. The other indices showed few responses along the gradients, which supports R theory. Measures of competitive effect and response did not differentiate the two theories. Conclusion: We show that some indices of competition show a decline with increased stress and disturbance, while other indices do not. Therefore, it is necessary to choose a competition index appropriate to the question being asked. Competitive importance and absolute competition were responsive to changes in stress and disturbance, while the other indices were not.

The use of digital photos to assess visual cover for wildlife in rangelands

Grassland vegetation can provide visual cover for terrestrial vertebrates. The most commonly used method to assess visual cover is the Robel pole. We test the use of digital photography as a more accurate and repeatable method. We assessed the digital photography method on four forage grassland species ( Pseudoroegneria spicata, Festuca campestris, Poa pratensis, Achnatherum richardsonii). Digital photos of 2-dimensional cutout silhouettes of three bird species sharp-tailed grouse, western meadowlark and savannah sparrow were used to model the impact of clipping (i.e., grazing) on visual cover. In addition, photos of artificial voles were used to model litter on cover available to small mammals. Nine sites were sampled and data were analyzed by the dominant grass species in each study plot. Regression analysis showed that digital photos ( r 2 = 0.62) were a better predictor than the Robel pole ( r 2 = 0.26) for assessment of cover. Clipping heights showed that clipping at less than 15 cm left the silhouettes 50% exposed. Digital photo analysis revealed that visual cover was affected by the type of grass species, with F. campestris > P. pratensis > A. richardsonii > P. spicata. Biomass and litter were both positively related to cover for small mammals.

Tree and forest encroachment into fescue grasslands on the Cypress Hills plateau, southeast Alberta, Canada

Tree encroachment into rough fescue ( Festuca campestris) grassland has been identified as an ecological concern on the Cypress Hills plateau in southeastern Alberta, Canada. A combination of field sampling (109 transects), a dendrochronological assessment (1361 trees), and a time series analysis of remotely sensed images from five different time periods (1950–2002) were used to determine the extent and rate of tree encroachment and forest development. Tree cover increased by 768 ha (∼51%) between 1950 and 2007, representing 10% of the study area, from 1502 ha of pre-1950 forest. Post-1950 tree invasion also created an ingress zone of 750 ha (∼10% of study area) based on field transects. Forest cover increased at a consistent rate of 14.3 ha/year. Lodgepole pine ( Pinus contorta var. latifolia) was the most common tree species associated with encroachment. Invasion based on the number of established trees occurred at an exponential rate of 3.1%/year after 1890, with density increased by filling spaces adjacent to and between trees within the grassland vegetation. The rate of tree establishment increased to 4.4%/year after 1980, suggesting a change occurred in environmental conditions. Annual atmospheric temperatures increased 0.55 °C from 1929 to 2005 ( P < 0.001), with winter (December–February) and spring (March–May) temperatures accounting for most of the increase ( P < 0.001), whereas summer (June–August) temperatures slightly decreased ( P < 0.050, 0.34 °C) and precipitation increased ( P < 0.005, 30 mm). Cattle and elk ( Cervus elaphus) grazing was not considered a primary factor for explaining tree encroachment. Based on multidimensional scaling, lodgepole pine establishment was associated with warmer spring temperatures and greater fall (October–November) precipitation. A landscape devoid of wildfires, combined with greater moisture availability, and a longer frost-free season is likely conducive to the sustained establishment of coniferous trees and forest development within the Cypress Hills fescue grassland ecosystem. Long-term conservation of the fescue grasslands could be possible by reintroducing fire.

Festuca campestris alters root morphology and growth in response to simulated grazing and nitrogen form

Summary 1. Large herbivores are known to spatially concentrate and alter the form of nitrogen (N) in grassland systems, which can modify aboveground plant chemical composition and productivity, and result in shifts in grazing pressure in these areas. Root responses to grazing under high N inputs may facilitate these changes, but their responses are less well understood. 2. We examined biomass, root morphology and demography, and nitrogen pool responses of Festuca campestris Rydb. seedlings grown in pots in an environmental chamber and subject to heavy fertilization with isotopically‐labelled N in a NO3‐N or NH4‐N fertilizer treatment, and to no clipping or clipping to 4 cm twice during the experiment. 3. Festuca campestris exhibited re‐growth patterns after defoliation that reflected preferential allocation to aboveground shoots, with percent recovery of shoot biomass twice that of roots. Clipping did not increase the risk of root mortality. Instead, reduced root biomass in clipped plants resulted from slowed elongation and decreased production of new roots. Although roots with smaller diameters and at lower density had a greater risk of root mortality, clipping did not alter the mean root diameter or level of root branching. 4. Under high N fertilization, NH4‐N increased the amount of aboveground biomass, ameliorated the effects of clipping on root production and further reduced the risk of root mortality in clipped plants. N‐form had no effect on root morphology. 5. While total plant N uptake and the percent utilization of fertilizer were lower in clipped plants, total plant nitrogen accumulated per root biomass (g g−1) at harvest was higher in clipped plants. 6. Our findings indicate that where defoliation is coupled with high nitrogen return, Festuca campestris recuperates by increasing nitrogen uptake, shifting production to favour recovery of aboveground biomass, and mitigating carbon losses by decreasing investment in new, actively growing roots. Because application of a more mobile form of nitrogen (NO3‐N) did not alter root morphology, root physiological responses may be most important for re‐growth when nitrogen is not limiting. Root reductions associated with grazing may have a greater impact in locations where grazer‐mediated nitrogen return is spatially decoupled from defoliation.