scholarly journals Buffel grass in Queensland's semi-arid woodlands: response to local and landscape scale variables, and relationship with grass, forb and reptile species

2009 ◽  
Vol 31 (3) ◽  
pp. 293 ◽  
Author(s):  
Teresa J. Eyre ◽  
Jian Wang ◽  
Melanie F. Venz ◽  
Chris Chilcott ◽  
Giselle Whish
Keyword(s):  
Habitat Preferences ◽  
Landscape Scale ◽  
Grazing Pressure ◽  
Critical Threshold ◽  
Hierarchical Partitioning ◽  
Grass Cover ◽  
Explanatory Variables ◽  
Buffel Grass ◽  
Remnant Vegetation ◽  
Reptile Species

Buffel grass [Pennisetum ciliare (L.) Link] has been widely introduced in the Australian rangelands as a consequence of its value for productive grazing, but tends to competitively establish in non-target areas such as remnant vegetation. In this study, we examined the influence landscape-scale and local-scale variables had upon the distribution of buffel grass in remnant poplar box (Eucalyptus populnea F.Muell.) dominant woodland fragments in the Brigalow Bioregion, Queensland. Buffel grass and variables thought to influence its distribution in the region were measured at 60 sites, which were selected based on the amount of native woodland retained in the landscape and patch size. An information-theoretic modelling approach and hierarchical partitioning revealed that the most influential variable was the percent of retained vegetation within a 1-km spatial extent. From this, we identified a critical threshold of ~30% retained vegetation in the landscape, above which the model predicted buffel grass was not likely to occur in a woodland fragment. Other explanatory variables in the model were site based, and included litter cover and long-term rainfall. Given the paucity of information on the effect of buffel grass upon biodiversity values, we undertook exploratory analyses to determine whether buffel grass cover influenced the distribution of grass, forb and reptile species. We detected some trends; hierarchical partitioning revealed that buffel grass cover was the most important explanatory variable describing habitat preferences of four reptile species. However, establishing causal links – particularly between native grass and forb species and buffel grass – was problematic owing to possible confounding with grazing pressure. We conclude with a set of management recommendations aimed at reducing the spread of buffel grass into remnant woodlands.

The ecological consequences of Buffel Grass Cenchrus ciliaris establishment within remnant vegetation of Queensland

2002 ◽  
Vol 8 (2) ◽  
pp. 99 ◽  
Author(s):  
Andrew J. Franks
Keyword(s):  
Ground Cover ◽  
Woody Species ◽  
Minor Role ◽  
Grass Cover ◽  
Cenchrus Ciliaris ◽  
Buffel Grass ◽  
Remnant Vegetation ◽  
South Central ◽  
Relative Cover ◽  
A Minor

The effects of Buffel Grass Cenchrus ciliaris presence and dominance in 78 Poplar Box Eucalyptus populnea woodland remnants of south central Queensland are documented, Buffel Grass was recorded from the majority of sites sampled, As the relative cover of Buffel Grass increased at both the quadrat and site level, the number of native ground cover species declined significantly. Most commonly recorded ground cover species displayed significant changes in frequency as Buffel Grass cover increased, Only two species increased with increased Buffel Grass cover: Desert Goosefoot Chenopodium desertorum subsp. anidiophyllum and Galvanised Burr Sclerolaena birchii. The average cover of Buffel Grass decreased significantly from the edge of remnants towards the core areas. The foliage projected cover of the sub-canopy layers appeared to be an important factor affecting the relative cover of Buffel Grass at any one site indicating that shading and competition with the woody layers are important determinants in the structure and composition of the ground cover layer. A number of sub-canopy species were found to produce leachates that were capable of significantly reducing the germination or growth of Buffel Grass seeds, alluding that allelopathy may play a minor role in determining ground cover species assemblages. However, this result can only be interpreted conservatively in relation to its ecological relevance with effects related to competition with overstorey woody species being of greater importance. This study quantifies the long observed effect that the exotic perennial Buffel Grass excludes other ground cover species, which may have detrimental ramifications on the functioning of remnant native vegetation over much of the state. With the recent introduction of regulations controlling broad scale tree clearing on both freehold and leasehold lands in Queensland, it is now important to identify a range of issues pertaining to the effective on ground management of remnant vegetation located outside the existing nature refuge network.

scholarly journals NOTES ON THE ECOLOGY OF THE COLOMBIAN LEAFTOED GECKO (PHYLLODACTYLUS TRANSVERSALIS), ENDEMIC TO MALPELO ISLAND

2016 ◽  
Vol 42 (2) ◽  
Author(s):  
Mateo López Victoria ◽  
Matthias Jurczyk ◽  
Volkmar Wolters
Keyword(s):  
Population Size ◽  
Breeding Season ◽  
Habitat Preference ◽  
Habitat Preferences ◽  
Original Description ◽  
Tropical Pacific ◽  
Reference Points ◽  
Eastern Tropical Pacific ◽  
Reptile Species ◽  
Malpelo Island

The Colombian leaf-toed gecko (Phyllodactylus transversalis) is the least known reptile species of Malpelo Island (Eastern Tropical Pacific). In the 37 years since its original description, no single study strictly dedicated to this species has been conducted. With the goal of providing information on the ecology and population size of this gecko, data collected during two visits to the island are presented. Behavior and reproduction were studied by following individuals during the night and by searching for hidden individuals and eggs during the day. Population’s density and habitat preferences were estimated by classifying the island’s surfaces into four types and counting geckos inside those habitats within band transects. General morphological measurements of geckos were performed as reference points for future comparisons. Phyllodactylus transversalis lays its eggs in narrow crevices of rocks, apparently communally. Reproduction seems to take place during most of the year, probably associated with the peak breeding season of seabirds. Although conspecifics shared shelters during the day, densities during the night suggest no apparent habitat preference for foraging. Population size of this species was estimated at approximately 114000 individuals.

Landscape Influences on Stream Habitats and Biological Assemblages

2006 ◽  
Keyword(s):  
Landscape Scale ◽  
Riparian Zones ◽  
Total Abundance ◽  
Stream Channels ◽  
Urban Centers ◽  
Explanatory Variables ◽  
Agricultural Areas ◽  
Abundance And Distribution ◽  
Shallow Stream ◽  
Agricultural Regions

<em>Abstract.</em>—Wood is an important component of small to medium-sized streams in forested regions, but has been poorly studied in agricultural areas. Our goals were to (1) characterize the abundance, size, and distribution of wood in low-gradient streams in two agricultural regions, (2) quantify the influence of reach- and landscape-scale factors on the abundance and distribution of wood in these streams, and (3) compare trends across two study areas. Wood abundance was quantified in stream reaches in two diverse agricultural regions of the Midwestern United States: central Michigan and southeastern Minnesota. Wood abundance was quantified in 71 stream reaches, and an array of channel, riparian zone, and landscape features were characterized. Multiple regressions were conducted to predict abundance from those explanatory variables. We found that large wood was relatively scarce in these low-gradient streams compared to low-gradient streams in forested regions. Mean log size was greater, but total abundance was lower in Minnesota than Michigan. In Minnesota, greatest wood abundance and greatest extent of accumulations were predicted in wide, shallow stream channels with high substrate heterogeneity and woody riparian vegetation overhanging the channel. Models were dominated by reach-scale variables. In Michigan, largest densities of wood and accumulations were associated with catchments in hilly regions containing urban centers, with low soil water capacity, wide, shallow stream channels, low coarse particular organic matter standing stocks, and woody riparian zones. Models contained both reach- and landscape-scale variables. Difference in the extent of agricultural and forest land use/cover between Michigan and Minnesota may explain the differences in the models predicting wood variables. Patterns in wood abundance and distribution in these Midwestern streams differ from those observed in high gradient regions, and in low-gradient streams within forested regions. This has important implications for ecosystem processes and management of headwater streams in agricultural regions.

scholarly journals Age-Dependent Utilization of Shelters and Habitat in Two Reptile Species with Contrasting Intraspecific Interactions

Animals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 995
Author(s):  
Kolanek ◽  
Bury ◽  
Turniak ◽  
Szymanowski
Keyword(s):  
Spatial Ecology ◽  
Habitat Preferences ◽  
The Body ◽  
Intraspecific Interactions ◽  
Reptile Species ◽  
Active Protection ◽  
Age Dependent ◽  
Anguis Fragilis ◽  
Coronella Austriaca ◽  
Effective Conservation

Reptiles undergo worldwide decline driven mostly by habitat change. Detailed recognition of factors underlying spatial structure and habitat utilization is therefore a prerequisite of effective conservation of this group. While the body of data on spatial ecology of reptiles is rapidly growing, studies on social factors remain still underrepresented. We studied age-specific patterns of shelter use, range size, and habitat preferences in the context of intraspecific interactions in the smooth snake Coronella austriaca—known to exhibit intraspecific predation—and the limbless lizard slow worm Anguis fragilis—with no such behavior observed. Despite smaller availability of preferred microhabitats, juveniles of smooth snakes occupied habitat and shelters located at the edge of the population range that did not overlap with adults. No such pattern was observed in the slow worm. Our study indicates that intraspecific interactions affect the spatial ecology of squamates. Passive and active protection of habitat must include wide buffers to preserve the poorly detectable young fraction of the population.

Habitat Selection by 2 Closely Related Skinks, Egernia-Modesta Storr and Egernia-Whitii Lacepede (Lacertilia, Scincidae)

1986 ◽  
Vol 13 (2) ◽  
pp. 295 ◽  
Author(s):  
DA Milton ◽  
JM Hughes
Keyword(s):  
Habitat Selection ◽  
Human Disturbance ◽  
Habitat Preferences ◽  
Canopy Cover ◽  
Niche Separation ◽  
Grass Cover ◽  
Allopatric Populations ◽  
Narrow Zone ◽  
Current Distributions ◽  
Microhabitat Preferences

'The habitat and microhabitat preferences, and times of activity, of the skinks Egernia modesta and E. whitii were examined in southern Queensland where they coexist in a narrow zone. The above parameters were compared between locally sympatric and allopatric populations, in an attempt to determine whether there was evidence of niche separation in sympatry. E. modesta preferred open habitats with little canopy cover and high grass cover, adjacent to rocky retreats. E. whitii preferred rocky areas with well developed canopy and shrub layers. Both species were active throughout the day, although E. modesta was active later than E. whitii. No evidence was found of competition restricting habitat preferences where the two species coexisted. It is suggested that human disturbance has had some influence on current distributions of these species.

Grass response to shrub removal in two semi-arid vegetation communities.

2000 ◽  
Vol 22 (2) ◽  
pp. 220 ◽  
Author(s):  
M Page ◽  
RJS Beeton ◽  
JJ Mott
Keyword(s):  
Key Words ◽  
Grazing Pressure ◽  
Grass Cover ◽  
Ecosystem Impacts ◽  
Vegetation Communities ◽  
Specific Research ◽  
Stable Component ◽  
South West ◽  
Semi Arid ◽  
Arid Vegetation

The control of woody weeds in the mulga lands of south-west Queensland is commonly regarded as essential for restoration of degraded systems. However, these shrubs have become a dominant and stable component of many mulga land ecosystems, and their removal may have unknown ecosystem impacts. This paper reports an experiment to determine the effect of woody weeds and grazing pressure on grass recruitment, cover and diversity in two vegetation communities in Queensland's mulga lands. Both factors influence grass recruitment, cover and diversity, but the response differs between the two vegetation communities investigated. The overall grass cover is consistently greater in sites where woody weeds were removed, and where grazing pressure was lowest. However, in the Dunefields community the cover and frequency of grass plants responded more to the removal of woody weeds than in the Mulga Sandplain community. In contrast, in the Mulga Sandplain community the grasses responded more to reducing or removing grazing pressure. Results suggest that subtle differences between systems influence grass dynamics, highlighting the need for community-specific research and management. Key words: shrub removal, semi-arid vegetation, vegetation communities, woody weeds

Grazing pressure, land condition, productivity and profitability of beef cattle grazing buffel grass pastures in the subtropics of Australia: a modelling approach

2018 ◽  
Vol 58 (8) ◽  
pp. 1451 ◽  
Author(s):  
M. K. Bowen ◽  
F. Chudleigh
Keyword(s):  
Beef Cattle ◽  
Plant Biomass ◽  
Economic Effect ◽  
Economic Benefits ◽  
Grazing Pressure ◽  
Production Plant ◽  
Pasture Grass ◽  
Buffel Grass ◽  
Utilisation Rate ◽  
Land Condition

There is widespread evidence that beef cattle land managers in Queensland are using stocking rates for perennial pastures that are substantially higher than recommended guidelines, and some indication that these decisions are motivated by perceived financial and economic benefits. Considerable effort has been, and is currently being, applied by public-sector organisations to encourage producers to reduce grazing pressure from beef cattle across Queensland’s pastoral lands. A better understanding of the relationships among stocking rate, land condition and profitability of beef-grazing enterprises is imperative to better inform cattle producers and policy makers. The present study assessed the effect of grazing pressure and land condition on the productivity and profitability of a steer-turnover enterprise utilising buffel grass (Cenchrus ciliaris) pastures in central Queensland. A property-level, regionally relevant herd model was used to determine whole-of-business productivity and profitability over a 30-year investment period. Growth paths for steers from weaning to marketing were developed for 16 scenarios encompassing a range of pasture-utilisation rates (30%, 35% and 50% of annual biomass growth), land condition (A, B and C) and market targets (feedlot entry at 474 kg or slaughter at 605 kg). The economic effect of each scenario was assessed by comparison to a base scenario of 30% pasture utilisation and turn-off of slaughter steers. Our analyses demonstrated a large economic advantage from increasing grazing pressure above 30% utilisation for buffel grass pastures, even with assumptions of declining land condition and animal performance. For instance, producing slaughter steers under a 50% pasture-utilisation regime with a continuous decline in land condition from A to C (and, hence, productivity) over Years 10–30 was AU$21 772/annum more profitable than was a 30% pasture-utilisation strategy, which is widely recommended as closer to a long-term, safe utilisation rate. The present research has provided insights into the relationship between grazing pressure and economic returns of beef producers over the medium term. However, it should be considered as a scoping study due to the paucity of data for effects of utilisation rate on the productivity of buffel grass pastures and, hence, on land-condition rating. Further research is required to better understand the effects of utilisation rate of buffel grass, and other sown pasture grass and legume species, on plant biomass production, plant-diet quality for cattle, land-condition decline and cattle productivity.

scholarly journals Dynamic multi-species occupancy models of birds of high-altitude grasslands in eastern South Africa

2018 ◽  
Author(s):  
David H Maphisa ◽  
Hanneline Smit_Robinson ◽  
Res Altwegg
Keyword(s):  
High Altitude ◽  
Habitat Preferences ◽  
Bird Species ◽  
Bird Diversity ◽  
Grass Cover ◽  
Occupancy Models ◽  
Occupancy Dynamics ◽  
Pumped Storage ◽  
Species Occupancy ◽  
High Altitude Grasslands

Moist, high-altitude grasslands of eastern South African harbour rich avian diversity and endemism. This area is also threatened by increasingly intensive agriculture and land conversion for energy production. This conflict is particularly evident at Ingula, an Important Bird and Biodiversity Area located within the least conserved high-altitude grasslands and which is also the site of a new Pumped Storage Scheme. The new management seeks to maximise biodiversity through manipulation of the key habitat variables: grass height and grass cover through burning and grazing to make habitat suitable for birds. However, different species have individual habitat preferences, which further vary through the season. We used a dynamic multi-species occupancy model to examine the seasonal occupancy dynamics of 12 common grassland bird species and their habitat preferences. We estimated monthly occupancy, colonisation and persistence in relation to grass height and grass cover throughout the summer breeding season of 2011/12. For majority of these species, at the beginning of the season occupancy increased with increasing grass height and decreased with increasing grass cover. Persistence and colonisation decreased with increasing grass height and cover. However, the 12 species varied considerably in their responses to grass height and cover. Our results suggest that management should aim to provide plots which vary in grass height and cover to maximise bird diversity. We also conclude that the decreasing occupancy with increasing grass cover and low colonisation with increasing grass height and cover is a results of little grazing on our study site. We further conclude some of the 12 selected species are good indicators of habitat suitability more generally because they represent a range of habitat needs and are relatively easy to monitor.

Grazing and tree ‘clearing’ alter grass-associated invertebrate assemblages in an Australian tropical grassy woodland

2018 ◽  
Vol 40 (6) ◽  
pp. 539
Author(s):  
Wayne A. Houston ◽  
Alistair Melzer
Keyword(s):  
Grazing Intensity ◽  
Landscape Scale ◽  
Grazing Pressure ◽  
Functional Health ◽  
Associated Fauna ◽  
Resource Base ◽  
Invertebrate Abundance ◽  
Invertebrate Assemblages ◽  
Grazing Pressures

To evaluate the response of invertebrates to ‘clearing’ and grazing pressure impacts, a previously grazed but uncleared grassy woodland in central Queensland was manipulated to provide four grazing pressures (destocked, low, moderate and high) and two tree treatments (with trees, i.e. untreated, and ‘cleared’, i.e. trees and saplings poisoned with herbicides), with two replicates of each, making 16 plots in total. Monitoring was carried out in 1998, approximately four years post-establishment of the treatments. Two types of samples were taken: pitfall for ground-active fauna and suction for grass-associated fauna. Overall, 23 orders of invertebrates were sampled by pitfalls and 22 by suction. Significant effects of grazing on invertebrate assemblages were detected by both methods, but no effects were detected from ‘clearing’. There was a gradation in the invertebrate assemblages from low to high grazing pressure, the invertebrate assemblages in the paddocks with the highest grazing differing most from those in the destocked and low-grazing-pressure paddocks. Notwithstanding the lack of effect of ‘clearing’ at the assemblage level, ground-active invertebrates and some grass-associated invertebrates increased in abundance following ‘clearing’, possibly reflecting an increase in the quality of the resource base. However, ground-active invertebrates and grass-associated invertebrates showed contrasting responses to grazing pressure, the former increasing, possibly reflecting changes in trapability due to the more open vegetation structure at higher grazing pressures. The abundance of grass-associated invertebrates declined by 50–80% with increased grazing – although with complex changes in assemblage structure. Despite those declines, the basic trophic pyramid remained, and, along with that, the potential for recovery of invertebrate assemblages and associated ecosystem services with reduction in grazing intensity. With 80% of Queensland grazed, the reduction in invertebrate abundance has implications for the viability of insectivores, particularly mobile fauna such as birds, at a landscape scale. It is recommended that the utility of using suction samples as a basis for assessing ecosystem functional health be investigated and that grazing pressure be reduced to increase invertebrate assemblages of rangeland pastures and to improve sustainability.

Habitat Relationships of the Herpetofauna of Remnant Buloke Woodlands of the Wimmera Plains, Victoria.

1996 ◽  
Vol 23 (3) ◽  
pp. 363 ◽  
Author(s):  
SA Hadden ◽  
ME Westbrooke
Keyword(s):  
Species Richness ◽  
Significant Relationship ◽  
Soil Type ◽  
Grazing Pressure ◽  
Pitfall Trapping ◽  
Amphibian Species ◽  
Habitat Features ◽  
Site Characteristics ◽  
Reptile Species

Twelve remnants of woodland dominated by buloke (Allocasuarina leuhmannii [A. luehmannii]) in the Wimmera Plains of Victoria, Australia, were investigated to evaluate the habitat relationships of the herpetofauna. Reptiles and amphibians were assessed by pitfall trapping, systematic searching and recording of frog vocalisations. Site characteristics that are likely to affect the species richness of herpetofauna in buloke remnants were determined. Nine reptile and 4 amphibian species were recorded from 6048 trap-nights and 216 h of systematic searching. A significant relationship was found between the herpetofaunal and reptile species richness and the level of past grazing pressure and vegetation understorey structure. No correlation was found between herpetofaunal species richness and the area of the remnant. Species richness of amphibians was best predicted by soil type. Habitat features associated with each species are presented. Implications for the management of remnant buloke woodlands and their herpetofauna are discussed and recommendations made.

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