Graminoid Cover Research Articles

The Spatial Distribution and Ecological Impacts of Aeolian Soil Erosion in Kangerlussuaq, West Greenland

Aeolian soil erosion is responsible for erosional landforms, or deflation patches, that are ubiquitous in the Kangerlussuaq region of West Greenland. Deflation patches are identifiable as bare regions within a mosaic of shrub and graminoid tundra, and have the potential to alter regional carbon cycling and vegetation dynamics. Understanding the spatial distribution of deflation patches is an important first step in establishing the drivers, controls, and ecological impacts of wind erosion in the region. Using high-resolution WorldView-2 satellite imagery, we created a land cover classification and percentage vegetation cover map to investigate the regional distribution and variability of deflation patches. Across the study area, deflation patches account for 22 percent of the terrestrial land surface and occur in greater density closer to the Greenland Ice Sheet (GrIS). Farther away from the GrIS, local topography plays a larger role in determining the distribution of deflation patches, with wind erosion tending to occur on steep south–southeast-facing slopes. Parallels between the distribution of deflation patches and local wind patterns suggest that katabatic winds are an important driver behind deflation patch occurrence. Within deflation patches, graminoid cover increases with distance from the GrIS, due either to a lesser degree of erosion or to a longer recovery time. In the context of recent circumpolar shrub expansion, deflation might locally limit the dominance of shrubs by creating habitat more suitable for graminoids and is an important factor to consider when predicting vegetation changes in West Greenland.

Beneficiary feedback effects on alpine cushion benefactors become more negative with increasing cover of graminoids and in dry conditions

Summary In facilitative interactions, the beneficiary feedback effect (BFE) has been defined as the effect of beneficiary species (facilitated species) on their benefactor. BFEs have been shown to be dependent on environmental conditions and the composition of the beneficiary community. In alpine cushion systems, BFEs are more negative with more abundant, diverse and phylogenetically aggregated communities of beneficiary species. We tested the hypothesis that the functional composition of the beneficiary communities correlates with the direction and strength of BFE received by alpine cushion benefactors and specifically that a more negative BFE would occur with increasing density of graminoids and a more positive BFE would occur with increasing density of forbs and legumes. Additionally, we predicted that the negative BFE of graminoids would increase with increasing summer aridity. We used a data base of alpine cushion communities from 30 sites throughout the world to assess the overall relationship between the composition of beneficiary communities and the total flower density of cushion benefactors, and its variation with increasing drought. Additionally, in order to assess more precisely the role of the functional composition of the beneficiary communities on BFE in a very dry site with cushion benefactors exhibiting contrasting functional compositions of beneficiary communities, we also designed a field study in the Qilian Shan mountain range (China). At this site with a highly continental climate, we compared the number of flowers and fruits of different phenotypes of the alpine cushion species Thylacospermum caespitosum hosting numerous graminoids, numerous forbs or very few beneficiary species. In the intercontinental study, we found a negative relationship between graminoids and cushion benefactor flower density but no effect of other functional groups. The negative BFE of graminoids increased with increasing summer drought. In the dry Qilian Shan range, we found both a negative effect of graminoids on total flower density and a positive effect of forbs on flower density and fruit set. Our study indicates that the context dependence of BFE may be partially explained by the composition of beneficiary communities and in particular the negative effect of graminoids.

Vegetation and Permafrost Thaw Depth 10 Years after a Tundra Fire in 2002, Seward Peninsula, Alaska

The recovery of tundra vegetation and the depth of permafrost thaw were observed on the Seward Peninsula, Alaska, the site of a wildfire in 2002. The study compared the vegetation in burned and adjacent unburned tundra from 5 to 10 years post-fire. The effects of the fire on the vegetation varied between species and were spatially variable at the stand scale. The cover of evergreen shrubs, bryophytes, and lichens was still drastically decreased 5 years after the fire and had not recovered even 10 years after the fire. By contrast, the cover of graminoids, especially Eriophorum vaginatum, and of the deciduous shrub Vaccinium uliginosum increased. The depth of permafrost thaw increased, and its spatial pattern was related to vegetation structure; specifically, deeper thaw corresponded to graminoid-rich areas, and shallower thaw corresponded to shrub-rich areas. As the E. vaginatum cover increased, the thaw depth recovered to that of the unburned area, and the spatial variation had disappeared 10 years after the fire. Our results indicate that both the prefire vegetation structure and the differences in the regrowth properties between species play important roles in the early stage of tundra ecosystem recovery after wildfire. Our findings also show that the favorable growing conditions related to deeper thaw do not last long.

Vegetation Response to Burn Severity, Native Grass Seeding, and Salvage Logging

AbstractAs the size and extent of wildfires has increased in recent decades, so has the cost and extent of post-fire management, including seeding and salvage logging. However, we know little about how burn severity, salvage logging, and post-fire seeding interact to influence vegetation recovery long-term. We sampled understory plant species richness, diversity, and canopy cover one to six years post fire (2006 to 2009, and 2011) on 72 permanent plots selected in a stratified random sample to define post-fire vegetation response to burn severity, post-fire seeding with native grasses, and salvage logging on the 2005 School Fire in eastern Washington. Understory vegetation responded rapidly post fire due, in part, to ample low intensity rainfall events in the first post-fire growing season. Vegetation was more diverse with greater plant species richness and diversity (Shannon-Wiener index) in low and moderate burn severity plots in 2006 (species richness 18; diversity 2.3) compared to high burn severity plots (species richness 10; diversity 1.8), with species richness on the high severity plots reaching 19 in the sixth post-fire year, similar to the initial values on the low and moderate burn severity plots. Plants that commonly resprout from rhizomes, bulbs, and other surviving belowground sources were abundant post fire, while those establishing from off-site seed sources, including non-native species, were present but not abundant. Plots seeded with native grass post fire and not salvage logged had the highest canopy cover of graminoid species: more than 30 % six years after the fire (in 2011), with low forb (15 %) and shrub (1 %) canopy cover and species richness. For comparison, high severity plots that were not seeded and not salvage logged had 3 % graminoid cover, 14 % forb cover, and 26 % shrub cover. Plots that had been salvage logged from one to three years after the fire produced less canopy cover of shrubs and forbs, but three times more canopy cover of graminoids on the high burn severity plots by 2011. High severity plots that were salvage logged and not seeded with native grasses had the lowest species richness, diversity, and cover. Very few non-native species were found, regardless of salvage logging and seeding. Rapid post-fire growth dominated by native plants of high diversity suggests that this forest’s vegetation and soils are highly resilient to disturbance. Overall, burn severity and post-fire seeding with native grasses were more influential than salvage logging on understory plant abundance one to six years after fire.

An Assessment of Metrics to Measure Seasonal Variation in and Grazing Effects on Riparian Plant Communities

Abstract. Several riparian plant community and streambank metrics were evaluated in 5 streams subject to grazing on public lands in central eastern Idaho. In this study, we evaluated 3 attributes associated with the ground cover on streambanks: percent cover of live vegetation, litter, and bare ground; and we evaluated 4 attributes that describe the vegetation community: plant species richness, wetland index value, percent cover of forbs, and percent cover of graminoids. We were particularly interested in how these attributes differed between grazed and ungrazed sites, how the attributes changed through time, and ultimately how the attributes were able to discriminate the effects of livestock grazing. We found that 2 metrics, percent live vegetation and bare ground, consistently reflected a seasonal effect of grazing. Litter cover also consistently reflected overall seasonal differences, but results often were not significant. Results for species richness suggested this metric may be most applicable when ...

Recovery of small pile burn scars in conifer forests of the Colorado Front Range

The ecological consequences of slash pile burning are a concern for land managers charged with maintaining forest soil productivity and native plant diversity. Fuel reduction and forest health management projects have created nearly 150,000 slash piles scheduled for burning on US Forest Service land in northern Colorado. The vast majority of these are small piles (<5m diameter). Similar to larger piles, we found that burning small piles had significant immediate effects on soil nutrients and physical and chemical properties and native plant cover. To evaluate the need to rehabilitate small piles and compare the effectiveness of treatment options, we examined soil and plant responses to treatments designed to alter soil nutrients, moisture and temperature and to increase seed availability. We compared four surface treatments (soil scarification, woodchip mulch, tree branch mulch, untreated scars), with and without addition of a native seed mixture. Natural recovery and treatment effects were examined for 2.5years after pile burning at 19 conifer forest sites along the Colorado Front Range. Woodchip mulch had dramatic effects on soil moisture, temperature, decomposition and inorganic soil N compared to the other treatments, untreated scars or unburned areas; woodchip mulch also suppressed plant establishment. Seeding increased total native species richness as expected, but had marginal effects on forb cover and no effect on graminoid cover. Soil N availability and plant cover did not differ from unburned areas in the absence of surface or seeding treatments within two years of pile burning. Neither reduced seed availability nor altered soil properties following burning hindered revegetation of these small burn scars by native herbaceous plants. Our findings indicate that rehabilitation may not be required for small burn pile scars except in sensitive areas, such as those with water quality and invasive plant concerns.

Modeling rates of life form cover change in burned and unburned alpine heathland subject to experimental warming.

Elevated global temperatures are expected to alter vegetation dynamics by interacting with physiological processes, biotic relationships and disturbance regimes. However, few studies have explicitly modeled the effects of these interactions on rates of vegetation change, despite such information being critical to forecasting temporal patterns in vegetation dynamics. In this study, we build and parameterize rate-change models for three dominant alpine life forms using data from a 7-year warming experiment. These models allowed us to examine how the interactions between experimental warming, the abundance of bare ground (a measure of past disturbance) and neighboring life forms (a measure of life form interaction) affect rates of cover change in alpine shrubs, graminoids and forbs. We show that experimental warming altered rates of life form cover change by reducing the negative effects of neighboring life forms and positive effects of bare ground. Furthermore, we show that our models can predict the observed direction and rate of life form cover change at burned and unburned long-term monitoring sites. Model simulations revealed that warming in unburned vegetation is expected to result in increased forb and shrub cover and decreased graminoid cover. In contrast, in burned vegetation, warming is predicted to slow post-fire regeneration in both graminoids and forbs and facilitate rapid expansion in shrub cover. These findings illustrate the applicability of modeling rates of vegetation change using experimental data. Our results also highlight the need to account for both disturbance and the abundance of other life forms when examining and forecasting vegetation dynamics under climatic change.

Rangeland dynamics: investigating vegetation composition and structure of urban and exurban prairie dog habitat.

Rapid human population growth and habitat modification in the western United States has led to the formation of urban and exurban rangelands. Many of these rangelands are also home to populations of black-tailed prairie dogs (Cynomys ludovicianus). Our study aimed to compare the vegetation composition of an urban and exurban rangeland, and explore the role that prairie dogs play in these systems. The percent absolute canopy cover of graminoids (grasses and grass-likes), forbs, shrubs, litter, and bare ground were estimated at sampling areas located on and off prairie dog colonies at an urban and an exurban site. Herbaceous forage quality and quantity were determined on plant material collected from exclosure cages located on the colony during the entire growing season, while a relative estimate of prairie dog density was calculated using maximum counts. The exurban site had more litter and plant cover and less bare ground than the urban site. Graminoids were the dominant vegetation at the exurban plots. In contrast, mostly introduced forbs were found on the urban prairie dog colony. However, the forage quality and quantity tests demonstrated no difference between the two colonies. The relative prairie dog density was greater at the urban colony, which has the potential to drive greater vegetation utilization and reduced cover. Exurban rangeland showed lower levels of impact and retained all of the plant functional groups both on- and off-colony. These results suggest that activities of prairie dogs might further exacerbate the impacts of humans in fragmented urban rangeland habitats. Greater understanding of the drivers of these impacts and the spatial scales at which they occur are likely to prove valuable in the management and conservation of rangelands in and around urban areas.

Red deer impacts on the montane Racomitrium lanuginosum moss-heath community in north-west Scotland

Background: The effect of sheep grazing on the internationally important moss-heath community of the British uplands has been well studied but less is known about the impact of red deer (Cervus elaphus).Aim: To compare the impact of different densities of red deer on bryophytes and lichens associated with moss-heath vegetation at Beinn Eighe National Nature Reserve (low deer density) and a traditional sporting estate at Letterewe (with higher deer density), Scotland.Methods: Suitable pairs of summit study sites were selected at random, and species cover data were collected from thirty 1-m2 quadrats at each location. The dung pellet group count method was used to estimate red deer usage. Generalised linear models were fitted to the data.Results: Mean graminoid cover was significantly higher in two of the Letterewe study sites compared with their Beinn Eighe counterparts. Bryophyte cover and height in general matched the pattern for Racomitrium lanuginosum in that they were not significantly different between any of the study site pairings.Conclusions: Despite differences in mean deer density between the Beinn Eighe and Letterewe properties as a whole, red deer numbers actually using the exposed summit moss-heath vegetation were estimated to be very low. Therefore, bryophyte cover within the Letterewe summit study sites was not significantly different from that at Beinn Eighe.

Vegetation patterns in small boreal streams relate to ice and winter floods

Summary In‐stream and riparian vegetation are species rich, productive and dynamic. Their patterns in small boreal streams are largely driven by seasonal flow regimes. Traditionally, flow‐related processes during the growing season, particularly the spring flood, have been seen as the most important, whereas vegetation has been viewed as being dormant and ‘less affected' during winter. Riparian and in‐stream vegetation were inventoried during the summers 2011–2013 in eight reaches of northern Swedish streams. Along each reach, the ice formation was surveyed during winter by visual inspections and with permanently placed cameras. We then evaluated the potential effects of ice regimes and winter flooding on riparian and in‐stream vegetation during 3 years by relating the abundance of winter floods caused by anchor ice to the cover, composition and biomass of vegetation. We found that the numbers of winter floods were higher along reaches with anchor‐ice formation than in reaches without. We also found that species diversity of riparian vegetation was higher in the reaches with anchor ice. This resulted from a lower cover of riparian dwarf shrubs and a higher cover of graminoids and forbs along reaches with anchor ice. We also found a lower cover of in‐stream algae but a higher cover of bryophytes in anchor‐ice reaches. These patterns were consistent throughout the study period although there were interannual differences in temperature, water levels and ice cover. During our study period, we encountered an average of 20 shifts per winter between freezing and thawing, while there was an average of 10 shifts per winter during 1960–1990. This indicates a warming climate in high latitudes. Higher temperatures and more shifts between freezing and thawing may initially increase ice dynamics. However, with further increases in mean temperature, ice production should eventually decrease. Synthesis. Ice and winter floods caused by anchor ice appear to be important disturbance agents that allow less competitive species to establish along small boreal streams. If ice dynamics is reduced, the composition and production of riparian and in‐stream vegetation may be changed, with possible consequences for the entire stream ecosystem.

Pile burning creates a fifty-year legacy of openings in regenerating lodgepole pine forests in Colorado

Pile burning is a common means of disposing the woody residues of logging and for post-harvest site preparation operations, in spite of the practice’s potential negative effects. To examine the long-term implications of this practice we established a 50-year sequence of pile burns within recovering clear cuts in lodgepole pine forests. We compared tree, shrub and herbaceous plant abundance and documented indicators of soil degradation in openings where logging residue was piled and burned as part of post-harvest site preparation and the adjacent forests regenerating after clear cutting. We found that pile burning creates persistent 10–15m diameter openings with lower tree densities (<500treesha−1; stems >2.54cm diameter at 1.4m height) compared to surrounding regenerating pine stands (2000–5000treesha−1). Low tree seedling and sapling densities (stems <2.54cm diameter at 1.4m height) in the openings (10–20% of regenerating forest), suggest they will remain poorly-stocked into the future. We observed evidence of high severity burning, including layers of soil charcoal and hardened red soil across the time series, but no sign that water infiltration, compaction or other indicators of soil degradation were consistent barriers to plant recolonization. Forb and graminoid cover, for example, was higher in the burn scar openings compared to regenerating forests. Pile burn openings are formed by the loss of pine seed during burning and short-term soil changes, but it is uncertain what factors maintain the openings during subsequent decades. As conducted for site preparation, the herbaceous plant-dominated openings are not extensive (<5% cover within clear cut units), and we found few invasive, non-native plants and no indication that soil conditions were sufficiently altered to explain 50years of poor tree regeneration. Nevertheless, persistence of the openings and recent increases in the number and size of piles from fuels and bark beetle salvage treatments has prompted resource managers to consider options for utilization and on-site retention of harvest residue.

A resurvey of late-lying snowpatches reveals changes in both species and functional composition across snowmelt zones

Alpine snowpatches are areas that, due to topographical and climatic factors, retain snow long after the thaw in the surrounding landscape. Within snowpatches there are often reliable patterns of snowmelt resulting in differences in plant composition, with snowpatch specialists limited to areas of late snowmelt. In 2013, we resurveyed vegetation in early, mid and late snowmelt zones across seven alpine snowpatches in the Snowy Mountains, Australia, 6 years after the initial 2007 survey. In both surveys, there were differences in vegetation cover and species composition among snowmelt zones; in particular, the cover of graminoids was higher in areas of earlier thaw. Differences in functional composition between survey periods were determined using functional traits (plant height, percent leaf dry matter content and specific leaf area) to calculate community trait-weighted means. In both surveys, early and mid snowmelt zones were dominated by taller species with larger leaves, mostly graminoids. Notably, by 2013 there was an increase in species richness in the late snowmelt zone and an increase in the cover of the tall tussock grass Poa costiniana across all snowmelt zones, driving changes in the community trait-weighted means for plant height and specific leaf area in the late snowmelt zone. The results highlight that snowpatch vegetation can change within relatively short time periods and that snowpatch plant communities may not remain as discrete units in the near future due to the encroachment of more competitive and productive species from the surrounding landscape.

Long term defoliation by cattle grazing with and without trampling differently affects soil penetration resistance and plant species composition in Agrostis capillaris grassland

There are no long-term experimental studies dealing with plant community responses to trampling. Here we report the results for soil penetration resistance and plant species changes in mesotrophic temperate Central European grassland after 12-years of grazing management with and without trampling by cattle. Five grazing treatments (intensive and extensive grazing; cut for hay in June followed by intensive or extensive grazing; and intensive grazing with no trampling under permanent electric fencing) with two replicate blocks have been applied since 1998. Species richness, species composition, sward height, nutrient availability in soil and soil penetration resistance were recorded and evaluated. For statistical analysis we used one way ANOVA and RDA with the Monte Carlo test. Long term grazing by large herbivores had a significant effect on soil penetration resistance with the lowest values in the ‘not trampled’ treatment. Legumes, particularly Trifolium repens, and short forbs (especially Veronica serpyllifolia) were supported by intensively defoliated and trampled treatments, whereas tall forbs (mainly Aegopodium podagraria, Hypericum maculatum) prevailed under the extensively managed treatments. The cover of tall and short graminoids was not dependent on applied treatments. The ‘not trampled’ treatment had the highest prevalence of bryophytes (domination of Rhytidiadelphus squarrosus) and was also the richest in a number of vascular plant species; however, it also had the lowest evenness index. Long-term defoliation by grazing animals without trampling does not lead to the creation of typical pasture swards. Species forming pasture communities are essentially dependent on regular defoliation by grazing and regular trampling by hooves, which causes a high degree of soil compaction as well as sward disruption.

The Role of Nitrogen Deposition in Widespread Plant Community Change Across Semi-natural Habitats

Experimental studies have shown that deposition of reactive nitrogen is an important driver of plant community change, however, most of these experiments are of short duration with unrealistic treatments, and conducted in regions with elevated ambient deposition. Studies of spatial gradients of pollution can complement experimental data and indicate whether the potential impacts demonstrated by experiments are actually occurring in the ‘real world’. However, targeted surveys exist for only a very few habitats and are not readily comparable. In a coordinated campaign, we determined the species richness and plant community composition of five widespread, semi-natural habitats across Great Britain in sites stratified along gradients of climate and pollution, and related these ecological parameters to major drivers of biodiversity, including climate, pollution deposition, and local edaphic factors. In every habitat, we found reduced species richness and changed species composition associated with higher nitrogen deposition, with remarkable consistency in relative species loss across ecosystem types. Whereas the diversity of mosses, lichens, forbs, and graminoids declines with N deposition in different habitats, the cover of graminoids generally increases. Considered alongside previous experimental studies and survey work, our results provide a compelling argument that nitrogen deposition is a widespread and pervasive threat to terrestrial ecosystems.

Effects of overstory retention, herbicides, and fertilization on sub-canopy vegetation structure and functional group composition in loblolly pine forests restored to longleaf pine

The desirable structure of longleaf pine forests, which generally includes a relatively open canopy of pines, very few woody stems in the mid-story, and a well-developed, herbaceous ground layer, provides critical habitat for flora and fauna and contributes to ecosystem function. Current efforts to restore longleaf pine to upland sites dominated by second-growth loblolly pine require information about how restoration treatments affect sub-canopy vegetation. We established a field experiment at Fort Benning in Georgia and Alabama, USA to determine the effects of four levels of approximately uniform canopy density (Control [∼16m2/ha basal area], MedBA [∼9m2/ha basal area], LowBA [∼5m2/ha basal area], and Clearcut [0m2/ha basal area]) and three cultural treatments (NT [untreated], H [chemical control of woody and herbaceous vegetation] and H+F [chemical control plus fertilization]) on vegetation structure and functional group composition for three growing seasons following canopy removal. In general, cover (a measure of abundance) of ground layer vegetation increased with the amount of canopy removal. The ground layer was dominated by herbaceous vegetation in each year. Canopy trees generally suppressed the cover of graminoids in the first two years after treatment but only the Control plots had lower graminoid cover than Clearcut plots after the third growing season. Forb cover was significantly lower on Control plots than on Clearcut plots after only the first growing season, and woody stems/shrubs had lower cover on Control plots than on LowBA or Clearcut plots in each year. Vegetation cover increased following the first year after canopy removal, and the relative dominance of functional groups did not change through time. Canopy retention limited the development of mid-story woody stems, with the greatest stem densities in the Clearcut plots. The herbicide treatment (on both H and H+F) significantly reduced woody stem density in the mid-story in 2009, but the effect was no longer significant in 2010. Traditional methods for converting stands of other pine species to longleaf pine commonly include clearcutting followed by planting, but our results suggest that clearcutting may release woody vegetation to increase mid-story stem densities and will reduce the amount of pine needles in the fuel bed. Retaining low to moderate levels of canopy density (5–9m2/ha basal area) in loblolly pine stands may provide an effective balance for reaching multiple restoration objectives that include maintaining desirable vegetation structure and creating fuel conditions for a frequent fire regime.

Overstory and Understory Dynamics in a Ponderosa Pine Plantation Vary with Stand Density in the Sierra Nevada: 40-Year Results

We periodically measured overstory ponderosa pine (Pinus ponderosa) growth and understory cover and abundance in a long-term study on the west slope of the Sierra Nevada, California, USA. The study was established in 1969 in a 20-year-old plantation, thinned to basal areas of 9, 16, 23, 30, and 37 m2 ha−1 and rethinned three times. The objective was to determine the effect of stand density regimes on productivity, understory vegetation, aboveground carbon storage, and mortality caused mainly by Dendroctonus infestations. Results showed that without mortality, basal area and volume increments were not affected by thinning the plantation to 16 m2 ha−1 from 37 m2 ha−1. With Dendroctonus actively attacking trees, the plantation could be thinned to 9 m2 ha−1 without sacrificing volume increment, because the level of mortality increased with stand density index. The thinning intensity did not affect the abundance of understory vegetation but did affect the cover of understory trees and graminoids. Intensively managed plantations could sequester and store the same amount of carbon as less intensively managed plantations. However, because fire is a major component in a pine-dominant ecosystem, carbon in larger diameter trees would be more resilient to wildfire than carbon in small diameter trees or understory vegetation.

Limited effect of hare grazing and short-term climatic variations on the most common alpine vegetation community in the Snowy Mountains, Australia

Background: In the alpine zone of the Snowy Mountains, grazing by mammals is limited. However, introduced European hare numbers have increased since the 1970s. Aims: To estimate the density of hares and hence grazing pressure among years. To assess the response of biomass, vegetation height and composition to a cessation of hare grazing. Methods: We used indices of hare abundance based on spotlighting and counts of hare pellets on a transect. The effect of hare grazing on tall alpine herbfield was assessed by using 15 paired exclosure and control quadrats for six years. Results: The indices of hare abundance suggested densities similar to those in upland areas of Britain. Grazing did not affect the composition, cover of herbs or graminoids or, for 2010, vegetation height or biomass. Variation in vegetation and hare numbers among years was not correlated with climatic variables. Observations of selective grazing suggested that impacts on vegetation may be localised and restricted to certain species. Prior analyses of hare pellets indicated that hares might spread seed of native and exotic species. Conclusions: Hares are having no general effect on tall alpine herbfield but may affect certain plant species via selective grazing or by spread of viable seed.

The Effect of AMF Suppression on Plant Species Composition in a Nutrient-Poor Dry Grassland

Arbuscular mycorrhizal fungi (AMF) are expected to be one of the key drivers determining the diversity of natural plant communities, especially in nutrient-poor and dry habitats. Several previous studies have explored the importance of AMF for the composition of plant communities in various types of habitats. Surprisingly, studies of the role of AMF in nutrient-poor dry grassland communities dominated by less mycotrophic plant species are still relatively rare. We present the results of a 3-year study in which a plant community in a species-rich dry grassland was subjected to the fungicide carbendazim to suppress AMF colonization. We tested the effect of the fungicide on the following parameters: the plant species composition; the number of plant species; the cover of the rare, highly mycorrhiza-dependent species Aster amellus; the cover of the dominant, less mycorrhiza-dependent species Brachypodium pinnatum; and the cover of graminoids and perennial forbs. In addition, we examined the mycorrhizal inoculation potential of the soil. We found that the suppression of AMF with fungicide resulted in substantial changes in plant species composition and significant decrease in species richness, the cover of A. amellus and the cover of perennial forbs. In contrast the species increasing their cover after fungicide application were graminoids—the C3 grasses B. pinnatum and Bromus erectus and the sedge Carex flacca. These species appear to be less mycorrhiza dependent. Moreover, due to their clonal growth and efficient nutrient usage, they are, most likely, better competitors than perennial forbs under fungicide application. Our results thus suggest that AMF are an essential part of the soil communities supporting a high diversity of plant species in species-rich dry grasslands in nutrient-poor habitats. The AMF are especially important for the maintenance of the populations of perennial forbs, many of which are rare and endangered in the area.

Conservation potential of prescribed fire for maintaining habitats and populations of an endangered rattlesnake Sistrurus c. catenatus

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 22:51-60 (2013) - DOI: https://doi.org/10.3354/esr00529 Conservation potential of prescribed fire for maintaining habitats and populations of an endangered rattlesnake Sistrurus c. catenatus Martin Dovčiak1,*, Portia A. Osborne1,2, David A. Patrick1,3, James P. Gibbs1 1State University of New York, College of Environmental Science and Forestry (SUNY ESF), Syracuse, New York 13210, USA 2Present address: Blanton & Associates, Austin, Texas 78734, USA 3Present address: Paul Smith’s College, Paul Smiths, New York 12970, USA *Email: mdovciak@esf.edu ABSTRACT: Many endangered species rely on early successional habitats to complete parts of their life cycles. We examined whether prescribed fire can be used to aid in conservation of the endangered eastern massasauga rattlesnake Sistrurus catenatus catenatus Raf. by maintaining open-canopy early successional summer habitats that this species requires for thermoregulation (basking). Using a formal experimental design, we characterized vegetation, surface temperature, moisture, and snake occurrence in control and burned treatments before and after prescribed fire. Prescribed fire increased vegetative cover and thereby decreased ground temperature compared to pre-treatment and control conditions, whereas rattlesnake occurrence increased dramatically after the prescribed fire. A habitat suitability model indicated that snake presence was negatively affected by forb cover, which became more dominant relative to other vegetation in the absence of fire. Prescribed fire also increased the cover of legumes and maintained graminoid cover and high overall plant functional diversity—all of which decreased in the absence of fire. In conclusion, prescribed fire stimulated overall vegetation growth while promoting varied microhabitats that included greater proportions of graminoids and sufficient number of patches of bare ground, both locally associated with warmer temperatures and presence of this endangered species of rattlesnake. KEY WORDS: Basking habitat conservation · Disturbance · Habitat management · Old field · Succession Full text in pdf format PreviousNextCite this article as: Dovčiak M, Osborne PA, Patrick DA, Gibbs JP (2013) Conservation potential of prescribed fire for maintaining habitats and populations of an endangered rattlesnake Sistrurus c. catenatus. Endang Species Res 22:51-60. https://doi.org/10.3354/esr00529 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 22, No. 1. Online publication date: November 07, 2013 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2013 Inter-Research.

The Legacy of Destructive Snow Goose Foraging on Supratidal Marsh Habitat in the Hudson Bay Lowlands

Ecological succession and climate change are pushing tundra as well as Arctic and subarctic lowland plant communities toward increased woody vegetation cover. However, areas along the Hudson Bay Lowlands that are over-grazed by hyper-abundant lesser snow geese are experiencing drastic losses of grass, sedge, and woody cover. We assessed longterm changes in proportional ground cover and habitat patch characteristic at a subarctic supratidal marsh that was largely vacated by breeding snow geese over a decade ago. We found no evidence of habitat recovery. Rather, snow geese leave a legacy on the land that propagates degradation of habitat long after their direct removal of vegetation through foraging. Over a 35 year period, we documented a 46% reduction in graminoid cover and an 84% reduction in shrub cover, which led to smaller and more isolated patches of shrubs that many avian species depend upon for foraging and nesting. Recent experimental goose exclosures suggest that recovery of degraded habitat is possible, but habitat management at a large scale will require drastic reductions in lesser snow goose numbers.