The impact of heavy grazing on burrow choice in the pygmy bluetongue lizard, Tiliqua adelaidensis

2011 ◽  
Vol 38 (4) ◽  
pp. 299 ◽  
Author(s):  
Melissa Pettigrew ◽  
C. Michael Bull

Context Grazing pressure has directly altered and indirectly influenced natural ecosystems worldwide, and has affected and displaced many native species. The endangered pygmy bluetongue lizard Tiliqua adelaidensis is endemic to the mid-north of South Australia. It inhabits remnant native grasslands where it is reliant on the presence of natural spider burrows constructed by lycosid and mygalomorph spiders as refuge sites. These lizards spend the majority of the day associated with their burrow either in the burrow itself or basking at its entrance. The remnant native grasslands of South Australia have endured 200 years of agricultural changes and the introduction of domestic stock has meant that grazing pressure has substantially increased. The vegetation around a burrow is considered to be important in providing shelter for the lizard. However, too much vegetation may reduce basking opportunities and visibility of prey. Stock grazing has been maintained on the majority of sites that contain pygmy bluetongue populations and it is presumed that the lizards can tolerate some form of grazing. However, the level of grazing intensity directly influences the vegetation structure that surrounds the lizard burrows. Aims We aimed to investigate the consequences of severe grazing pressure on the choice of burrows by lizards, and on their burrow related behaviour. Methods We simulated heavy grazing pressure by manually removing aboveground vegetation in the field in replicated quadrats that contained artificial burrows, and by providing bare substrate in half of experimental enclosures in the laboratory. Key results In the field, lizards only occupied the artificial burrows in control quadrats, where vegetation had been left intact. In the laboratory, lizards that occupied both burrows basked for longer at the burrow entrance where vegetation was present. Conclusions Heavy grazing management that results in the majority of vegetation being removed could have a negative impact on pygmy bluetongue lizard recruitment and sustainability. Implications Grazing regimes should be carefully monitored to consider the needs of species that rely heavily on microhabitat structure for their persistence. For the endangered pygmy bluetongue lizard, heavy grazing should be avoided to promote amounts of vegetation suitable to sustain viable populations.

1994 ◽  
Vol 34 (2) ◽  
pp. 181 ◽  
Author(s):  
DJ Conlan ◽  
BS Dear ◽  
NE Coombes

The impact of grazing intensity and number of grazings was assessed on the growth and seed production of 5 annual pasture legumes [Trifoliunz subterraneum var. subterraneum cv. Karridale, var. brachycalycinum cv. Clare, var. yanninicum cv. Trikkala; Medicago murex (murex medic) cv. Zodiac; Ornithopus compressus L. (yellow serradella) cv. Avila]. There were 7 grazing treatments: an ungrazed control; and 2 grazing intensities (light and heavy), each for 3 periods of grazing (winter, winter-early spring, winter-late spring). Tethered sheep in small experimental plots were used to provide controlled herbage removal across all cultivars through winter and winter-spring grazing. This grazing system resulted in significantly different levels of herbage being present in the light and heavy grazing treatments following each grazing period. Grazing had variable effects on seed production: <35% increase for Trikkala, and no significant effect for Karridale. Both cultivars continued growth and seed production late in the season after grazing pressure was removed on 8 November. Seed yield of Clare was reduced by 46-49% by heavy grazing treatments. Seed yield of murex medic was not significantly affected by grazing, while that of serradella was reduced by 30-55% by grazing late in the season. The seed yield responses show that cultivar and species responses to grazing may be highly variable. Under favourable spring conditions, Trikkala, Karridale, and murex medic can be grazed heavily until late in the season without adversely affecting seed yield, whilst Clare and Avila cannot.


2021 ◽  
Vol 2021 (23) ◽  
pp. 237-250
Author(s):  
Anatolii Morozov ◽  
◽  
Tetiana Morozova ◽  
Inessa Rutkovska ◽  
◽  
...  

Introduction.The main environmental risks posed by roads are population depletion (deaths on roads) and barrier effects (habitat fragmentation). Barrier effects - animals avoid crossing roads, which leads to a decrease in the size and quality of habitat, optimal population size, reduced ability to find food and partner, increased genetic structuring and local extinction (Forman et al. 2003; Andrews et al. 2015; van der Ree et al. 2015). These risks against the background of other stressors, in particular the presence of invasive species, pollution, pesticide use, climate change, plant and animal diseases, may threaten the survival of populations.This issue is especially relevant for herpetofauna due to their biological characteristics. In particular, reptiles and amphibians move slowly, are too small (for drivers to see), do not avoid roads, and in cold periods roads attract amphibians (thermoregulation) because the coating absorbs and retains heat (Case and Fisher 2001; Jochimsen et al. 2004).The principle of ensuring ecological continuity is to identify priority efforts to mitigate environmental risks for animals and reduce the negative impact of the transport complex as a spatial barrier and source of pollution by introducing a number of technical means (eco-crossings, screens, embankments, landscaping). As it is not possible to change the environmental risks on all roads and for all species at present, it is necessary to identify the most vulnerable species, assess the risks to populations and the need for mitigation based on analysis of road density and traffic intensity.Problem Statement. With the advent of land transport there was a progressive environmental problem - the transformation of landscapes, it first appeared in countries with developed road infrastructure in Western Europe and the United States, and quickly spread around the globe (Ellenberg, et al., 1981; Fetisov, 1999; Zagorodnyuk, 2006, Ilyukh, Khokhlov, 2012). Numerous publications by both foreign and domestic authors are devoted to the study of the impact of transport infrastructure. Special attention of European authors is paid to the study of the phenomenon of fragmentation of natural ecosystems. In Europe, there is a network of experts and institutions of IENE, which is studying the possibility of implementing preventive measures for landscape fragmentation, promotes the development of transport infrastructure in accordance with environmental requirements, by creating a safe, environmentally sustainable European transport infrastructure.The ecological trail of the road network significantly exceeds its length (Vozniuk, 2014). This is due to the effects of, in particular, mortality on the roads of mammals, reptiles, reptiles (Forman et al. 2003), landscape fragmentation (roads divide the area into isolated areas, with low populations (sometimes below the minimum), so such populations lose genetic diversity and may become extinct locally), the loss of habitats of species and a decrease in the level of connectivity. In addition to these obvious effects, noise and vibration pollution are added, which inhibit the ability of reptiles, birds and mammals to detect prey or avoid predators (Forman et al. 2003), disturbed light regime (Rich and Longcore 2006). Roads contribute to the development of soil erosion processes, the spread of invasive and introduced species (300-800 seeds/m2 per year are transported to roadside ecotones by vehicles (Von der Lippe and Kowarik 2007), which contributes to the formation of local pseudo-populations), create obstacles and sources. (Forman et al. 2003).Purpose. Substantiation of the principle of ecological continuity regarding the negative impact of transport infrastructure on natural ecosystems and search for possible ways to minimize and prevent such impact.Materials and methods. The main research methods are the application of theoretical general scientific approaches to study: analysis and synthesis of international and domestic scientific and theoretical works, EU documentation (charters, design requirements), Ukrainian legal framework, literature sources; collection and analysis of statistical data to identify the dangers of the impact of road infrastructure on biodiversity and determine the value of the natural landscape.Results. The result is an analysis of the scientific literature on the negative impact of transport infrastructure on animals, systematization of the main impacts for the preparation of methodological documents for organizations planning and designing transport infrastructure in Ukraine to reduce the negative impact.Conclusions. The principle of ensuring ecological continuity is to minimize the negative consequences for the environment. In particular, by leveling the spatial barrier of the public highway. When laying a road through natural ecosystems, it is necessary to build transitions and passages for animals. In this case, their density and type must correspond to the natural rank of the territory. The construction of crossings for animals should be mandatory for all types of roads that cross ecological corridors. This is especially true for smaller roads, completely devoid of any transitions for animals, noise shields (on such roads are more likely to hit animals). An important point is the need to plan preventive methods at the planning stage of road construction. The analysis of the European experience shows that the negative impact of transport infrastructure on biota can be solved by consolidating the efforts of road transport specialists and specialists in the field of nature protection.Keywords:motor road,wildlife crossing, biodiversity, road infrastructure, ecological continuity


2019 ◽  
Vol 41 (6) ◽  
pp. 535 ◽  
Author(s):  
C. M. Waters ◽  
S. E. McDonald ◽  
J. Reseigh ◽  
R. Grant ◽  
D. G. Burnside

Demonstrating sustainable land management (SLM) requires an understanding of the linkages between grazing management and environmental stewardship. Grazing management practices that incorporate strategic periods of rest are promoted internationally as best practice. However, spatial and temporal trends in unmanaged feral (goat) and native (kangaroo) populations in the southern Australian rangelands can result land managers having, at times, control over less than half the grazing pressure, precluding the ability to rest pastures. Few empirical studies have examined the impacts of total grazing pressure (TGP) on biodiversity and resource condition, while the inability to manage grazing intensity at critical times may result in negative impacts on ground cover, changes in pasture species composition, increased rates of soil loss and reduce the ability for soils to store carbon. The widespread adoption of TGP control through exclusion fencing in the southern Australian rangelands has created unprecedented opportunities to manage total grazing pressure, although there is little direct evidence that this infrastructure leads to more sustainable land management. Here we identify several key indicators that are either outcome- or activity-based that could serve as a basis for verification of the impacts of TGP management. Since TGP is the basic determinant of the impact of herbivory on vegetation it follows that the ability for rangeland pastoral management to demonstrate SLM and environmental stewardship will rely on using evidence-based indicators to support environmental social licence to operate.


2009 ◽  
Vol 31 (4) ◽  
pp. 427 ◽  
Author(s):  
P. Jones ◽  
P. Filet ◽  
D. M. Orr

The population dynamics of the palatable, perennial grasses Bothriochloa ewartiana (Domin) C.E.Hubb. (desert Mitchell grass), Chrysopogon fallax S.T.Blake (golden beard grass) and Heteropogon contortus (L.) P.Beauv. ex Roem. & Schult. (black speargrass), were studied in an extensive grazing study conducted in a eucalypt woodland within the Aristida–Bothriochloa pasture community in central Queensland between 1994 and 2000. Treatments were three grazing pressures based on light, medium and heavy utilisation of forage available at the end of summer and two timber treatments (trees intact and trees killed). Seasonal rainfall throughout this study was generally favourable for plant growth with no severe drought periods. Grazing pressure had a greater overall impact on plant dynamics than timber treatment, which had minimal impact. Grazing pressure had a large impact on H. contortus dynamics, an intermediate impact on B. ewartiana and no impact on C. fallax. Fluctuations in plant density of both B. ewartiana and C. fallax were small because both species were long lived with low levels of seedling recruitment and plant death, whereas fluctuations in H. contortus density were relatively high because of its relatively short life span and higher levels of both recruitment and death. Heavy grazing pressure increased the recruitment of B. ewartiana and H. contortus in some years but had no impact on that of C. fallax. Heavy grazing pressure reduced the survival of the original plants of both B. ewartiana and H. contortus but not of C. fallax. For H. contortus, the size of the original plants was larger where trees were killed than where trees were left intact and plants of the 1995 seedling cohort were larger in 1998 at heavy compared with those at light and medium grazing pressure. Grazing had a minor negative impact on the soil seed bank of H. contortus. Populations of all three species remained stable throughout this study, although the favourable seasonal rainfall experienced and the short duration of this study relative to the life span of these species may have masked longer term, deleterious impacts of heavy grazing pressure.


2017 ◽  
Vol 17 (1) ◽  
Author(s):  
Helena de Lima Müller ◽  
Rodrigo Ramos Lopes ◽  
Julia-Maria Hermann

Abstract Native grasslands in the Campos de Cima da Serra, Brazil, are being converted at speed for exotic tree plantations and cropland. The impact of modified and novel soil conditions on the establishment of native grassland species is unknown; establishment of non-native species, deliberately or accidentally introduced, could be favoured. In a common garden composed of fully randomized replicate samples of soils collected from remnant grassland, former cropland and pine plantations, we tested emergence and establishment of five cold-season species: Native low-tussock grass Piptochaetium montevidense (Spreng.) Parodi; native legume Trifolium riograndense Burkart; naturalized low-tussock grass Vulpia bromoides (L.) Gray; low-tussock grass Holcus lanatus L., cultivated and naturalized in Brazil; and a cultivar of non-native Trifolium repens. Other than expected, soil type and species*soil type interactions had no significant effect on seedling emergence after 132 days in the field. Species effect on seedling emergence, however, was highly significant. Vulpia bromoides emergence was significantly highest in all soil types. Holcus lanatus and Trifolium riograndense both achieved second highest emergence rates and did not differ significantly from each other. Lowest overall emergence rates were found in the non-native clover cultivar. Lab germination tests failed for Piptochaetium, although it showed reasonable emergence in the field. Good performance of the native clover is encouraging for future grassland restoration, but the value of highly germinable Vulpia as a forage remains to be tested. Holcus tolerates a wide range of soil conditions and its life history traits may promote naturalization, or even invasiveness. Native grasslands of the region should be monitored for this species. Studies like these, but set up on a larger geographical scale and with a wider array of native species, will be essential in developing ecological restoration methods for southern Brazilian grasslands.


2014 ◽  
Vol 73 (2) ◽  
pp. 419-435 ◽  
Author(s):  
Ivica Ljubičić ◽  
Mihaela Britvec ◽  
Sven D. Jelaska ◽  
Stjepan Husnjak

Abstract Optimal grazing pressure on rocky pastures is beneficial to the development of plant species and maintenance of plant diversity. Both abandonment of grazing and overgrazing gradually reduce plant diversity. This paper correlated abundance patterns of the flora on rocky pastures with the values of the chemical composition of the soil resulting from the degree of sheep grazing intensity. The study was carried out in the period from 2008 to 2010 on the islands of Pag, Krk and Cres. At 30 sites, 310 taxa of vascular plants were found. The highest plant diversity and 220 plant taxa were found on moderately grazed pastures. Abandoned pastures with a total of 93 plant taxa observed show the dominance of phanerophytes (35.5%) and the highest proportion of the Mediterranean floral element when compared to pastures of moderate and heavy grazing intensity. The highest concentration of total nitrogen in the soil (0.71%) was recorded on plots of heavy grazing intensity. The results of the study indicate that moderate grazing intensity, from 1 to 1.5 sheep ha−1, can be recommended on the northern Adriatic islands. This should contribute not only to the preservation of plant diversity, but also to the improvement of ecological sheep farming.


2019 ◽  
Vol 41 (6) ◽  
pp. 461 ◽  
Author(s):  
T. Atkinson ◽  
R. B. Hacker ◽  
G. J. Melville ◽  
J. Reseigh

In the southern rangelands of Australia, the capability of land managers to manage total grazing pressure, with support from their service providers, influences resource condition, livestock production and pastoral business profitability. This study investigated the perspectives of people who face the challenge of managing total grazing pressure. Self-administered surveys were used to collect the perspectives of 220 land managers and 46 service providers to total grazing pressure management and the impacts of grazing animals. Land managers and service providers agreed that, on average, 40 to 50% of the total demand for forage is due to non-domestic animals, that a reduction in this component is required, and that current levels are at least double the desirable level. The majority of respondents (&gt;54%) assessed both livestock and non-domestic animals to have a negative impact on soils and pastures. However, livestock were more frequently assessed to have a positive impact on soils and pastures than non-domestic animals. The respondents commonly suggested that the impact livestock have on soils and pastures depends on management. Non-domestic animals were assessed by the majority of respondents to have a negative impact on livestock production and business profitability, apart from unmanaged goats where opinions were divided. Both land managers and service providers used the ‘large negative’ category to describe the impact on livestock production and business profitability more frequently for kangaroos than for any other herbivore. There were significant differences in the respondents’ perspectives among the States. Respondents in New South Wales and Queensland estimated a higher proportion of demand for forage from non-domestic animals than respondents from other States. The respondents in New South Wales also more frequently assessed unmanaged goats to have a positive impact on business profitability compared with the other States. Total grazing pressure management was rated as a high priority issue by 66% of respondents. ‘Improved kangaroo management’ and ‘fencing’ were the two main factors identified with potential to make a substantial difference to total grazing pressure management in the next ten years.


Land ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 397
Author(s):  
Virginia Anne Kowal ◽  
Julian Ahlborn ◽  
Chantsallkham Jamsranjav ◽  
Otgonsuren Avirmed ◽  
Rebecca Chaplin-Kramer

Mongolia contains some of the largest intact grasslands in the world, but is vulnerable to future changes in climate and continued increases in the number of domestic livestock. As these are two major drivers of change, it is important to understand interactions between the impact of climate and grazing on productivity of Mongolia’s rangelands and the livelihoods they sustain. We use a gridded, spatially explicit model, the Rangeland Production Model (RPM), to explore the simultaneous and interacting effects of climate and management changes on Mongolia’s rangeland and future livestock production. Comparing the relative impact of temperature, precipitation, and grazing intensity, varied individually and in combination, we find that climatic factors dominate impacts on forage biomass and animal diet sufficiency. Site rainfall strongly mediates the impact of grazing on standing biomass, such that more productive or higher-rainfall sites are more vulnerable to increases in grazing pressure. Gridded simulations covering Mongolia’s Gobi-Steppe ecoregion show that while rangeland biomass is generally predicted to increase under future climate conditions, interactions among spatially varying drivers create strong heterogeneity in the magnitude of change.


2006 ◽  
Vol 17 (3) ◽  
Author(s):  
Lorna Cole ◽  
Meg Pollock ◽  
Duncan Robertson ◽  
John Holland ◽  
David McCracken

As a result of the European Community Common Agricultural Policy reform in 2005 it is predicted that livestock grazing in the Scottish uplands will become less intensive. At each of two upland research centres, two large (>40ha) plots were established to investigate the relationship between grazing intensity in the Scottish uplands and biodiversity. One plot was grazed intensively by sheep while the otherwas grazed extensively. Ground beetleswere sampled by pitfall trapping to determine the influence of grazing pressure on the ecologicalmake-up of ground beetle assemblages. Grazing intensity did not significantly influence carabid diversity. However, grazing intensity, altitude and moisture did influence the carabid ecological assemblage structure at both locations. Large flightless Carabus species were more abundant in extensively managed plots than intensively managed plots at both locations. It is likely that these long-living, relatively immobile beetles were favoured by the greater stability of the vegetation structure in the extensively grazed plots. Monitoring the ecological assemblage structure provides a more sensitive approach than diversity indices when comparing the impact of grazing and agricultural management but is also robust enough to allow direct comparisons between different geographical locations.


2021 ◽  
Vol 1 (43) ◽  
pp. 16-16
Author(s):  
Alexander Saakian ◽  
◽  

Environmental management is a priority for the development of science, technology and technology, which cannot be carried out without monitoring the state of the environment. Industrial-oriented natural ecosystems are experiencing significant anthropogenic pressures, resulting in an increased negative impact on the environment and a reduction in biodiversity. In this work, on the territory of the Kemerovo region - Kuzbass (on the territory of 19 administrative districts), an analysis of the impact of the area's planting on the number of hunting animals was carried out. This analysis was performed by correlation method. The source of information was official data for the period from 2015 to 2019 of the Ministry of Natural Resources and Ecology of Kuzbass, the Department for the Protection of Animal Objects of Kuzbass, the Department of Forestry of Kuzbass, the Federal State Statistics Service of Kuzbass. The results of the landfill study showed a decrease in dynamics, which is associated with intensification of agriculture, unfavorable climatic conditions and forest fires. The largest decrease in the level was observed in the Izhmorsky, Kemerovo, Mariinsky and Prokopyevsky districts. The results of the study of the dynamics of the number of hunting animals (ungulates, bears and fur animals) presented in this work showed a stable, annual growth in numbers. The predominant ungulates of the region are Siberian roe deer and European elk of 5 species, fur animals are white hare, squirrel, common beaver, ondatra, sable, common badger, European mink of 17 species of animals, bears in the region are represented by a brown bear. There was a high and moderate inverse dependence of the dynamics of the number of brown bear, ungulates on the influence of the salinity of the fixed hunting grounds of various territories. The results showed that the increase in the number of bears and ungulates negatively affects the greenland of certain territories, which does not contradict the literary data. Keywords: BIODIVERSITY, BIOLOGICAL RESOURCES, FORESTS OF REGIONS, RATIONAL ENVIRONMENTAL MANAGEMENT, KEMEROVO REGION, HUNTING ANIMALS, POPULATION DYNAMICS, QUANTITATIVE ANALYSIS


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