Effects of wildlife grazing on the production, ground cover and plant species composition of an established perennial pasture in the Midlands region, Tasmania

2012 ◽  
Vol 39 (2) ◽  
pp. 123 ◽  
Author(s):  
Rowan W. Smith ◽  
Mick Statham ◽  
Tony W. Norton ◽  
Richard P. Rawnsley ◽  
Helen L. Statham ◽  
...  

Context Management of grazing wildlife on private land in Tasmania is a contentious issue for landowners, animal-welfare groups and the Tasmanian Government. Wildlife species known to graze pasture include Tasmanian pademelon (Thylogale billardierii), Bennett’s wallaby (Macropus rufogriseus rufogriseus), forester kangaroo (Macropus giganteus), brushtail possum (Trichosurus vulpecula) and fallow deer (Dama dama). Understanding the spatio-temporal patterns of wildlife grazing is important when considering wildlife-control options to mitigate pasture loss; however, limited research has been undertaken. Aims To quantify the impact of wildlife grazing on pasture production and to assess the spatial and temporal pasture biomass loss from an established pasture; to investigate the effect of protecting pastures from wildlife grazing on species composition of an existing perennial pasture; to determine whether wildlife grazing contributes to a decline in the composition of improved pasture species over time and an increase in-ground cover of less desirable grasses and broadleaf weeds; and to examine whether protecting pastures from wildlife grazing could increase ground cover. Methods Pasture biomass loss to wildlife grazing was determined by a paired exclusion-cage method over a 26-month period from February 2008 to April 2010. A quantitative pasture model was used to simulate pasture growth at the study site. Changes in the botanical composition of the sward in response to wildlife grazing were determined by hand-separation, drying and weighing of harvested material, and also by visual estimation of the ground cover of individual plant species. A wildlife faecal-pellet survey was used to develop an index of wildlife feeding activity. Key results Pasture loss to wildlife grazing varied spatially and temporally. Pasture loss decreased with increasing distance from the edge of cover vegetation. The proportion of pasture lost increased during periods of slow pasture growth. Visual estimates of ground cover showed that grazing by wildlife resulted in an increase in bare ground in unprotected swards, whereas protection from grazing resulted in an increase in production of perennial and annual species, as determined by hand-separation of harvested material, and a decrease in bare ground as determined by visual estimate. Faecal-pellet surveys were found to be strongly correlated with pasture biomass losses. Conclusions The proportion of pasture loss to wildlife grazing was found to be influenced by distance from native vegetation and also by pasture availability, which was seasonal. Wildlife can alter the composition of pastures by reducing the ground cover and yield of improved grasses. Continual grazing of pastures by wildlife in addition to rotational sheep grazing may increase the amount of bare ground. Implications Wildlife-control methods need to be carefully chosen if the intended benefits of alleviating pasture biomass losses are to be achieved. Quantifying the loss of pasture is important because it enables the extent and significance of losses to be determined and may inform decisions about the most appropriate wildlife control measures to adopt. Controlling wildlife during periods of slow pasture growth may be important in preventing damage and yield loss of plant species actively growing during these times. Failure to control wildlife may result in a decrease in the composition of desirable plant species.

2018 ◽  
Vol 10 (9) ◽  
pp. 3153
Author(s):  
Ditmar Kurtz ◽  
Marcus Giese ◽  
Folkard Asch ◽  
Saskia Windisch ◽  
María Goldfarb

High impact grazing (HIG) was proposed as a management option to reduce standing dead biomass in Northern Argentinean (Chaco) rangelands. However, the effects of HIG on grassland diversity and shifts in plant functional groups are largely unknown but essential to assess the sustainability of the impact. During a two-year grazing experiment, HIG was applied every month to analyze the seasonal effects on plant species composition and plant functional groups. The results indicate that irrespective of the season in which HIG was applied, the diversity parameters were not negatively affected. Species richness, the Shannon–Wiener diversity index and the Shannon’s equitability index did not differ from the control site within a 12-month period after HIG. While plant functional groups of dicotyledonous and annual species could not benefit from the HIG disturbance, C3-, C4-monocotyledonous and perennials increased their absolute and relative green cover. Our results suggest that HIG, if not applied in shorter frequencies than a year, neither alters diversity nor shifts the plant species composition of the grassland plant community, but instead it promotes previously established rather competitive species. HIG could therefore contribute as an alternative management practice to the sustainable land use intensification of the “Gran Chaco” grassland ecosystem and even counteract the encroachment of “low value” species.


2016 ◽  
Vol 55 (1) ◽  
pp. 47-62 ◽  
Author(s):  
M. Walsh ◽  
J.P. Hanrahan ◽  
L. O’Malley ◽  
R. Moles

Abstract The frequency of individual plant species at ground level and the species composition of the unimproved vegetation on a western hill farm, stocked with Scottish Blackface sheep, were monitored from 1995 to 2008. Performance criteria of the flock that relied totally, or almost totally, on this vegetation for sustenance from 1994 to 2011 were evaluated. The frequency of vegetation increased over time (from 65% to 82% of the surface area; P < 0.05), with a corresponding decline in the frequency of bare soil, thus reducing vulnerability to soil erosion. This increased incidence of vegetation cover reflected increases in ‘other forbs’(P < 0.01), heather(P < 0.05)and grass (P < 0.08).A significant change (P < 0.05) also occurred in the species composition of the vegetation, reflecting an increase in the proportions of ‘other forbs’ (P < 0.05) and heather (P = 0.14), and a decline in the proportion of sedges (P = 0.14). A similar pattern occurred in the two main habitats: blanket bog and wet heath. Annual stocking rate (ewes per hectare, based on actual ewe grazing days) on the unimproved hill grazing averaged 0.9 (0.13 livestock units) per hectare prior to 1999 and 0.78 (0.11 livestock units) per hectare subsequently. There was no trend in weight gain of replacement females while confined to the unimproved hill area between weaning (14 weeks old) and first joining at 18 months of age. A negative trend (P < 0.01) occurred in the pre-weaning growth rate of lambs on the hill. The average number of lambs reared per ewe joined (reflecting fertility, litter size and ewe/lamb mortality) was 1.0, and this showed no evidence of change over time. The study flock performed 10% to > 60% better, depending on the variable, than similar flocks in the National Farm Survey at comparable stocking rates. A well-defined rational management system can sustain a productive sheep enterprise on unimproved hill land without negative consequences for the frequency or composition of the vegetation.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5413 ◽  
Author(s):  
Piotr Skórka ◽  
Magdalena Lenda ◽  
Dawid Moroń

Roads may have an important negative effect on animal dispersal rate and mortality and thus the functioning of local populations. However, road verges may be surrogate habitats for invertebrates. This creates a conservation dilemma around the impact of roads on invertebrates. Further, the effect of roads on invertebrates is much less understood than that on vertebrates. We studied the effect of roads on butterflies by surveying abundance, species richness and composition, and mortality in ten grassland patches along high-traffic roads (∼50–100 vehicles per hour) and ten reference grassland patches next to unpaved roads with very little traffic (<1 vehicle per day) in southern Poland. Five 200-m transects parallel to the road were established in every grassland patch: at a road verge, 25 m from the verge, in the patch interior, and 25 m from the boundary between the grassland and field and at the grassland-arable field boundary. Moreover, one 200-m transect located on a road was established to collect roadkilled butterflies. The butterfly species richness but not abundance was slightly higher in grassland patches adjacent to roads than in reference grassland patches. Butterfly species composition in grasslands adjacent to roads differed from that in the reference patches. Proximity of a road increased variability in butterfly abundances within grassland patches. Grassland patches bordering roads had higher butterfly abundance and variation in species composition in some parts of the grassland patch than in other parts. These effects were not found in reference grassland patches, where butterfly species and abundance were more homogenously distributed in a patch. Plant species composition did not explain butterfly species. However, variance partitioning revealed that the presence of a road explained the highest proportion of variation in butterfly species composition, followed by plant species richness and abundance in grassland patches. Road mortality was low, and the number of roadkilled butterflies was less than 5% of that of all live butterflies. Nevertheless, the number and species composition of roadkilled butterflies were well explained by the butterfly communities living in road verges but not by total butterfly community structure in grassland patches. This study is the first to show that butterfly assemblages are altered by roads. These results indicate that: (1) grassland patches located near roads are at least as good habitats for butterflies as reference grassland patches are, (2) roads create a gradient of local environmental conditions that increases variation in the abundance of certain species and perhaps increases total species richness in grassland patches located along roads, and (3) the impact of roads on butterflies is at least partially independent of the effect of plants on butterflies. Furthermore, (4) the direct impact of road mortality is probably spatially limited to butterflies living in close proximity to roads.


2018 ◽  
Vol 37 (2) ◽  
pp. 152-163
Author(s):  
Lýdia Kňazovičová ◽  
Silvia Chasníková ◽  
Ján Novák ◽  
Peter Barančok

AbstractVegetation of the ski slopes in the Low Tatras National Park in Slovakia was evaluated through the environmental variables and species composition caused by human impact assessment. We compared the grasslands located on pistes, off pistes and on the edge of pistes, and within these we also recorded the grassland management. The results show that the majority of study areas managed by transport of sod clippings has reached the lowest number of species; contrariwise, the grasslands with no management are characterized by the highest number of species. Areas on pistes managed by cutting correlates positively with the bare ground. Cover of mosses positively correlates with the total cover and areas with no management. Total of 17 synanthropic plant species and 2 nonnative species as the indicator of human interventions were noticed. They occurred particularly on the edge areas but also in the surroundings of the off piste areas.


Weed Science ◽  
1987 ◽  
Vol 35 (6) ◽  
pp. 807-812 ◽  
Author(s):  
Kay L. Mercer ◽  
Don S. Murray ◽  
Laval M. Verhalen

Full-season interference from unicorn-plant [Proboscidea louisianica(Mill.) Thell. # PROLO] at densities ranging from 0 to 32 weeds/10 m row was measured on weed and cotton (Gossypium hirsutumL. ‘Westburn M′) parameters in three Oklahoma environments. Linear regression models using log10transformations were superior to linear and comparable to quadratic models in estimating the impact of inter- and intraspecific competition. Weed measurements on an individual plant basis were not reliable indicators of interference. Weed dry biomass, ground cover, and seed capsule production/plot generally increased with increasing weed densities. In the three environments, densities of two, four, and eight weeds/10 m row initially reduced cotton plant height. Maximum height reductions averaged 20, 28, and 43% in the three environments but did not detrimentally affect the mechanical harvest of cotton. As unicorn-plant density (expressed in log10units) doubled (within a range of 1 to 32 plants/10 m of row), lint yield reductions ranged from 84 to 146 kg/ha. Maximum lint yield losses averaged 59, 65, and 74% in the three environments. Transforming lint yield/plot to a percentage of that from weed-free plots resulted in a single quadratic equation applicable over environments. Unicorn-plant at the highest weed density reduced fiber fineness, uniformity, and length, but not fiber strength.


2001 ◽  
Vol 2001 ◽  
pp. 146-146
Author(s):  
B. L. Keir ◽  
R. W. Mayes ◽  
E. R. Ørskov

Knowledge of the nutrition of free-ranging herbivores and the impact on their environment is often limited by lack of information concerning the botanical composition of their diets. For herbivores grazing heterogeneous vegetation environments, current methods for estimating the botanical composition of their diets are limited in their scope and accuracy. The purpose of this study was to establish whether urinary metabolites, occurring as a result of ingestion of different individual plant species, have the potential to be used as markers to estimate diet composition.


2021 ◽  
Vol 94 ◽  
pp. 1-16
Author(s):  
Łukasz Moszkowicz ◽  
Izabela Krzeptowska-Moszkowicz ◽  
Karolina Porada

Greenery is a natural value in urban space. To maintain the richness and diversity of greenery, it is necessary to understand the factors and mechanisms that influence vegetation. The purpose of this paper was to determine the impact of selected features of public parks and factors on the richness and diversity of herbaceous plants. In Krakow public parks, this richness and diversity is greater in parks with a larger area and habitat heterogeneity, the presence of migration corridors, and natural elements. Full stand coverage negatively affects diversity. Biologically inactive surface affects richness and diversity as well as a number of different groups of plant species. The presence of rare and non-synanthropic species is related to the park’s surface, natural elements, and its heterogeneity.


2016 ◽  
Vol 27 (1-2) ◽  
pp. 34-41
Author(s):  
I. N. Kovalenko

Reproduction in a broad sense is the process by which female parents generate some or other germs (diasporas) able to form new individuals that are genetically similar to the female parents. The two main types of reproduction are found in forest grasses and subshrubs: seed (or by spores in spore-bearing plants) and vegetative. The establishment of features of plan reproduction of grass and subshrub layer is an important scientific issue in the context of the preservation and restoration of forest ecosystems, because plants of grass and subshrub layer have a significant impact on the initial stages of natural regeneration of plants of the first layer. Some features of reproduction of plants of different layers of forest ecosystems – from grass to woody – have been studied on the basis of our own observations and literature data. The observations were carried out on the territory of Desnyansko-Starogutsky National Nature Park and the adjacent territories. Forest ecosystems of the north-east of Ukraine have been in active use for a long time. Currently, these forests, in part, have obtained conservation status, and the volume of logging has been sharply reduced. Therefore, the majority of forests are characterized by the progressive succession, during which the proportion of plant silvan species increases and, consequently, the number of motile vegetative plant species increases in the lower layers of forest. The eight plant species of grass and subshrub layer, such as Aegopodium podagraria L., Asarum europaeum L., Calluna vulgaris (L.) Hull, Carex pilosa Scop., Molinia caerulea (L.) Moench., Stellaria holostea L. Vaccinium myrtillus L., Vaccinium vitis-idaea L., have been selected as models. It is established that the capacity for vegetative propagation and clone formation is an important feature of reproduction of most forest grasses. The key parameters of generative reproduction of clone forming plants of grass and subshrub layer and their dependence on the ecological and coenotic factors have been shown as well. To establish the level of reproduction the following morphometric parameters were determined: weight of generative organs (g), number of generative shoots (pieces), reproductive effort (%), share of generative individuals in the population (%). In case of generative reproduction, an important biological characteristic is the so-called reproductive effort, which characterizes the contribution of organic matters and energy in the reproductive process. It is typically shown as the percentage of phytomass of the reproductive structures of the total phytomass. In general, generativity of the investigated plants of grass and subshrub layer was determined by the ecological and cenotic conditions, and therefore varied from association to association. Forest grasses and subshrubs, in turn, are an important factor for regeneration of all types of woody species in forest ecosystems. Depending on the composition and abundance of plants of grass and subshrub layer, the number of seedlings and little undergrowth of all woody species of trees is reduced in varying degrees, and the indicators of their growth are getting worse. The impact of the live ground cover on undergrowth of woody species is ultimately determined by the specificity of the ecological and coenotic situation in the areas of regeneration and the specific ecological and phytocoenotic properties of undergrowth of certain woody species. The main environmental problems of recreational zones from the perspective of possibilities of natural regeneration of woody species are the effect of mechanical actions on the soil. Grass and subshrub layer as a sensitive indicator of the increase in anthropogenic load is the first to undergo such transformation in recreational forests. Under its influence its species composition varies and is depleted, distribution of certain species as well as their phytomass and projective cover decrease. Many forest species disappear from the cover, and weeds begin to grow. Protection of forests as holistic ecosystems is an important issue, being developed during the XX century, and not having lost its significance even today. The main directions of its solution are connected with the development of the ecological network of Ukraine and the proper use of all forest resources.


Sign in / Sign up

Export Citation Format

Share Document