The relative impacts of grazing, fire and invasion by buffel grass (Cenchrus ciliaris) on the floristic composition of a rangeland savanna ecosystem

2015 ◽  
Vol 37 (3) ◽  
pp. 227 ◽  
Author(s):  
Roderick J. Fensham ◽  
Jian Wang ◽  
Cameron Kilgour
Keyword(s):  
Floristic Composition ◽  
Original Data ◽  
Livestock Grazing ◽  
Perennial Grasses ◽  
Floristic Diversity ◽  
Cenchrus Ciliaris ◽  
Land Clearing ◽  
Buffel Grass ◽  
Eastern Australia ◽  
Floristic Data

The relative impacts of grazing, fire and invasion by buffel grass (Cenchrus ciliaris) on floristic diversity and composition were evaluated for a Eucalyptus savanna ecosystem used for rangeland pastoralism in north-eastern Australia. Floristic data from a 10-year fire and livestock grazing experiment spanning periods of drought and above-average rainfall and multi-scaled data from varying levels of invasion by buffel grass were analysed. These original data were supplemented by the results of other studies. Light grazing by cattle had no discernible impacts on plant diversity and composition and burning resulted in a short-term pulse of annual forb abundance. Minor variations in edaphic properties had a substantial influence on floristic composition. Large perennial grasses increased in abundance with rainfall and annual forbs were abundant after rainfall events during drought. Species richness was diminished substantially at scales up to 1000 m2 by buffel grass and native perennial grasses showed the greatest declines. Land clearing, which facilitates invasion by buffel grass, has been greatly reduced by legislative controls but after nearly half of the savanna ecosystem has been cleared. The study suggests that livestock grazing with light to moderate stocking rates and burning are compatible with the conservation of floristic diversity in savannas but the invasion of buffel grass will continue to diminish diversity and represents a threat for the future. Land clearing exacerbates the spread of buffel grass and the control of this practice is an important contribution to the conservation of savannas.

The effects of grazing and fire on vegetation and the vertebrate assemblage in a tropical savanna woodland in north-eastern Australia

2007 ◽  
Vol 23 (1) ◽  
pp. 95-106 ◽  
Author(s):  
Alex. S. Kutt ◽  
John C. Z. Woinarski
Keyword(s):  
Vegetation Type ◽  
Floristic Composition ◽  
Ground Cover ◽  
Fire Effects ◽  
Wet Season ◽  
Eastern Australia ◽  
North Eastern ◽  
Floristic Data ◽  
Vertebrate Assemblage ◽  
Tussock Grasses

We studied the response of vegetation and vertebrate assemblages to fire and grazing, and their interacting effects, in Eucalyptus woodland in north-eastern Australia. In this vegetation type, many pastures remain free of cattle grazing due to the occurrence of a native shrub poisonous to livestock. Vegetation (floristic data and 22 habitat variables) and vertebrate fauna (birds, mammals, reptiles) were sampled in 29 standardized 50 × 50-m quadrats in the 2001 wet season, representing four treatments: sites burnt recently (within 2 y) and grazed by cattle (4–8 ha per livestock unit); sites unburnt (last burnt >2 y ago) and grazed; sites burnt recently and ungrazed; and unburnt and ungrazed sites. Fire and grazing had a significant influence on vegetation: both grazing and fire reduced ground cover (fire in grazed sites 51–23%, fire in ungrazed sites 68–39%) and increased the cover of forbs (8% in burnt and grazed sites, 3% if ungrazed) and tussock grasses (20% in grazed and unburnt sites and 5% when ungrazed). Grazing caused a shift in floristic composition from the perennial hummock grass Trioda pungens to tussock grasses (e.g. Aristida spp., Enneapogon spp.), forbs (e.g. Phyllanthus spp.) and shrubs (e.g. Acacia spp.). Of the vertebrate groups, birds responded more to fire effects (9 species), reptiles to grazing effects (6 species) and mammals to the interaction (2 species). Species reacted to increases in bare ground (e.g. crested pigeon Ocyphaps lophotes, hooded robin Melanodryas cucullatus, Ctenophorus nuchalis) and to the dominant ground cover (e.g. Ctenotus pantherinus) or change in vegetation architecture (e.g. singing honeyeater Lichenostomus virescens, variegated fairy-wren Malurus lamberti). The clearest example of an interacting effect was the cycle of complementary dominance between the rodents Pseudomys delicatulus and P. desertor, the latter's post-fire recovery becoming more muted in sites where cattle grazed (modelled time for population recovery twice as long as in ungrazed sites).

Conservation of the Grassy White Box Woodlands: Rangewide Floristic Variation and Implications for Reserve Design

1996 ◽  
Vol 44 (1) ◽  
pp. 57 ◽  
Author(s):  
SM Prober
Keyword(s):  
Arable Land ◽  
Floristic Composition ◽  
Livestock Grazing ◽  
Reserve Design ◽  
Grass Species ◽  
Parent Materials ◽  
Prominent Component ◽  
Eastern Australia ◽  
Floristic Variation ◽  
Almost All

Grassy white box (Eucalyptus albens Benth.) woodlands once covered several million hectares of the wheat-sheep belt of south-eastern Australia. The pre-European floristic composition of these woodlands is little-known, as almost all of them were rapidly cleared for cropping or modified by livestock grazing. Woodland remnants were surveyed across NSW, to describe rangewide variation in the woodland flora, and to provide a basis for reserve design. As far as could be detected from current remnants, some of the major features of the original grassy white box woodland understorey appear to have been relatively constant across NSW: on a wide variety of soils and parent materials from southern to northern NSW, the dominant native grasses in little-disturbed sites were generally Themeda australis (R.Br.) Stapf andor Poa sieberiana Sprengel, and many of the subsidiary herbs and grasses occurred across this range. There were, however, several natural patterns of variation requiring consideration in conservation planning: about half of the subsidiary herb and grass species showed a relationship with latitude, probably relating to a climatic gradient; the understorey became more shrubby, with a sparser and more varied grass component, on soils classed as being 'unsuitable for agriculture'; and on basalt parent materials of the Inverell Plateau, Dichanthium sericeum (R.Br.) A.Camus may have been a more prominent component of the understorey. Natural floristic variation was overlain by patterns resulting from European disturbance, as indicated by floristic distinctions between sites of differing landuse. While these distinctions were partly related to poorer soil resource class in State Forests and Nature Reserves, grazing by livestock and tree clearing are likely to to have contributed to them. Reserves in ine whire box woodiands are presentiy few, and are not representative of the naturai variation. ~ o s t existing reserves occur on soils unsuited to agriculture, compared with the grazing or arable land of typical grassy woodland. Cemetery remnants, rail easements, Travelling Stock Reserves and roadsides provide the best opportunities for conservation on higher-quality soils. Remnant quality declined significantly in southern NSW, indicating a need for greater conservation effort in southern areas.

Drought resistance of native and introduced perennial grasses of south-eastern Australia

2005 ◽  
Vol 56 (11) ◽  
pp. 1261 ◽  
Author(s):  
T. P. Bolger ◽  
A. R. Rivelli ◽  
D. L. Garden
Keyword(s):  
Drought Resistance ◽  
Perennial Grass ◽  
Livestock Grazing ◽  
Perennial Grasses ◽  
Severe Drought ◽  
South Eastern ◽  
Eastern Australia ◽  
Dehydration Avoidance ◽  
Leaf Survival ◽  
South Eastern Australia

Perennial grasses are the key to the economic and environmental sustainability of pastures for livestock grazing in south-eastern Australia. Mortality of perennial grasses can occur during drought periods and there is anecdotal evidence of differences in drought resistance among species, but information on the basic ecophysiological responses of these species to drought is lacking. An experiment was conducted to determine the responses of 7 native and 3 introduced perennial grass species to continuous drought. Leaf survival during severe drought varied among the species nearly 4-fold, from 11 to 40 days, and was considered a measure of their overall drought resistance. All of the species had good dehydration tolerance, so the differences in drought resistance were related more to their dehydration avoidance traits, specifically to the amount of water available to the plant at the point where plant transpiration became minimal. The native species had both the longest and shortest leaf survival periods, with the introduced species ranking intermediate. Species exhibited various morphological traits that contributed to dehydration avoidance during severe drought, including leaf folding or rolling, rapid leaf shedding, and large amounts of cuticular wax. The results are discussed in terms of their implications for perennial grass persistence in south-eastern and in south-western Australia.

Manipulating livestock grazing to enhance native plant diversity and cover in native grasslands

2013 ◽  
Vol 35 (1) ◽  
pp. 95 ◽  
Author(s):  
J. A. Mavromihalis ◽  
J. Dorrough ◽  
S. G. Clark ◽  
V. Turner ◽  
C. Moxham
Keyword(s):  
Plant Diversity ◽  
Livestock Grazing ◽  
Perennial Grasses ◽  
Small Scale ◽  
Native Plant ◽  
Sheep Grazing ◽  
Annual Species ◽  
Total Species Richness ◽  
Eastern Australia ◽  
Native Plant Diversity

Temperate perennial grasslands globally have been subject to extensive biodiversity loss. Identifying livestock grazing regimes that maintain and enhance the diversity and cover of native plant species in these ecosystems remains a key challenge. The responses of vegetation to different sheep grazing regimes were assessed over 3 years in grasslands of south-eastern Australia. An open communal experimental design was used to assess the effects of varying season and duration of exclusion of grazing by sheep, replicated at three locations. Manipulation of season and duration of exclusion of grazing led to few major changes in the cover of native perennial grasses or forbs, although seasonal variation was considerable. Exclusion of grazing in the spring did increase the likelihood of occurrence of grazing-sensitive native forb species but also lead to an increase in the cover of exotic annual species. However, cover of exotic annual species tended to decline with increasing duration of exclusion, while the abundance of native, grazing-sensitive forbs and the cover of perennial grasses increased. Small-scale richness of native perennial forb species increased with a 3-month period of exclusion of grazing, but declined with year-round exclusion of sheep. Total species richness also declined in response to year-round exclusion of sheep and rates of decline were correlated with the rate at which herbage mass accumulated. While strategic grazing did not result in major vegetation changes in the short term, it is suggested that some grazing exclusion may enhance the survival of infrequent species most sensitive to sheep grazing. Caution, however, should be taken when grazing regimes implemented benefit both desirable (native forbs) and undesirable (exotic annuals) species. Having a mosaic of flexible grazing management regimes across the landscape is likely to be beneficial for native plant diversity.

Reed (Phragmites australis agg.) dominated plant communities in the Lower Volga Valley

2015 ◽  
pp. 26-37
Author(s):  
V. B. Golub ◽  
V. V. Bondareva ◽  
A. N. Sorokin ◽  
L. F. Nikolaychuk
Keyword(s):  
Expert System ◽  
Phragmites Australis ◽  
Plant Communities ◽  
Floristic Composition ◽  
Original Data ◽  
Optimal Level ◽  
Point Of View ◽  
Original Structure ◽  
Volga River ◽  
Lower Volga

Plant communities with reed domination (Phragmites australis agg.) occupy the large areas in the Lower Volga Valley and especially in the river delta. We have set the task to reveal the diversity of these communities in the Lower Volga Valley. For this purpose, we applied the database that is registered in the Global Index of Vegetation-Plot Databases (GIVD) under the EU-RU–002 index (http://www.givd.info/) and includes 14871 relevés made during the period from 1924 to 2013. Communities with the dominance of reed were defined as such, if the coverage of this plant was more than 50 %. We have found 375 such relevés in the database. At first, one basal community, 3 associations and 3 subassociations with domination of Phragmites australis agg. were distinguished in the Lower Volga Valley. All processing and analysis of relevés were performed using the software package JUICE 7.0. (Tichý, 2002). The «Cocktail» method was applied to establish the sociological groups that indicate environmental conditions (Bruelheide, 2000). The expert system for selection from the database of relevés by means of these groups was created. It is allowed us to ascribe relevés to earlier distinguished associations, subassociations and basal community. 171 relevés have been identified by the expert system and they were assigned to association, subassociation or the basal community. 204 relevés were not referred to any association, subassociation or the basal community. We wanted to answer the question: are there among these 204 relevés, which could be interpreted as the new syntaxa, giving them the proper ecological characteristics? For this purpose, the cluster analysis of 204 relevés has been carried out. The optimal level of clustering was determined by calculating the index of “crispness of classification” (Botta-Dukát et al., 2005). The greatest “crispness of classification” was reached at allocation of 13 clusters. Consideration of the floristic composition of allocated groups had shown that 11 of them were the transitional plant communities among the earlier established syntaxa. Only two clusters were differed in rather original structure that we could explain by the influence of environment factors. We have identified them as new associations Rubio tataricae-Phragmitetum australis and Cynancho acuti-Phragmitetum australis. All associations with the dominance of Phragmites australis agg. distinguished in the Lower Volga Valley were included in the alliance Phragmition communis Koch 1926, order Phragmitetalia communis Koch 1926. In literary sources from the ecological point of view these syntaxa are defined as the wetland communities, which are closely linked to water bodies (Šumberová et al., 2011; Ermakov, 2012). However, in many cases this definition does not correspond to the ecology of plant communities with the dominance of reed in the lower reaches of the Volga River. Ecotops of these communities are flooded for up to 2–3 months in a year and then they dry out. In the autumn, the ground water level can drop to a depth of one meter (Golub et al., 2011). The plant satellites of the reed here are often mesophytic plants such as Rubus caesius, Calamagrostis epigeios, Phalaris arundinacea, Rubia tatarica, Althaea officinalis, and Rumex stenophyllus. Therefore, the inclusion of phytocoenosises with domination of the reed in the lower reaches of the Volga River in the alliance Phragmition communis is rather relative. A correct placement of these plant communities in the system of vegetation syntaxa of the arid areas can be made only if it is based on original data obtained from much bigger territory than the Lower Volga Valley. In future geobotanical studies, it is desirable to divide the aggregation of Phragmites australis agg. into smaller species taxa.

scholarly journals Evolutionary history and genetic connectivity across highly fragmented populations of an endangered daisy

Heredity ◽  
2021 ◽  
Author(s):  
Yael S. Rodger ◽  
Alexandra Pavlova ◽  
Steve Sinclair ◽  
Melinda Pickup ◽  
Paul Sunnucks
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Genetic Differentiation ◽  
Evolutionary History ◽  
Livestock Grazing ◽  
Genetic Connectivity ◽  
Evolutionary Divergence ◽  
Common Component ◽  
A Genome ◽  
Eastern Australia

AbstractConservation management can be aided by knowledge of genetic diversity and evolutionary history, so that ecological and evolutionary processes can be preserved. The Button Wrinklewort daisy (Rutidosis leptorrhynchoides) was a common component of grassy ecosystems in south-eastern Australia. It is now endangered due to extensive habitat loss and the impacts of livestock grazing, and is currently restricted to a few small populations in two regions >500 km apart, one in Victoria, the other in the Australian Capital Territory and nearby New South Wales (ACT/NSW). Using a genome-wide SNP dataset, we assessed patterns of genetic structure and genetic differentiation of 12 natural diploid populations. We estimated intrapopulation genetic diversity to scope sources for genetic management. Bayesian clustering and principal coordinate analyses showed strong population genetic differentiation between the two regions, and substantial substructure within ACT/NSW. A coalescent tree-building approach implemented in SNAPP indicated evolutionary divergence between the two distant regions. Among the populations screened, the last two known remaining Victorian populations had the highest genetic diversity, despite having among the lowest recent census sizes. A maximum likelihood population tree method implemented in TreeMix suggested little or no recent gene flow except potentially between very close neighbours. Populations that were more genetically distinctive had lower genetic diversity, suggesting that drift in isolation is likely driving population differentiation though loss of diversity, hence re-establishing gene flow among them is desirable. These results provide background knowledge for evidence-based conservation and support genetic rescue within and between regions to elevate genetic diversity and alleviate inbreeding.

LIGULE: An evaluation of indigenous perennial grasses for dryland salinity management in south-eastern Australia. 2. Field performance and the selection of promising ecotypes

2001 ◽  
Vol 52 (3) ◽  
pp. 351 ◽  
Author(s):  
Meredith L. Mitchell ◽  
T. B. Koen ◽  
W. H. Johnston ◽  
D. B. Waterhouse
Keyword(s):  
Field Performance ◽  
Perennial Grasses ◽  
Wagga Wagga ◽  
South Eastern ◽  
Eastern Australia ◽  
Dactylis Glomerata L ◽  
Salinity Management ◽  
Selection Of ◽  
Broad Overview ◽  
South Eastern Australia

This paper reports the results of an initial evaluation of a large collection of Australian perennial native grasses. The overall aim of the research was to identify accessions that may be useful for pastoral purposes and for controlling land degradation on hill-lands in the high (>500 mm) rainfall zone of south-eastern Australia. Accessions (807) representing 37 target species were established in spaced plant nurseries at Rutherglen and Wagga Wagga. Dactylis glomerata L. cv. Porto and Eragrostis curvula (Schrad) Nees. Complex cv. Consol were established as comparator (control) species. A range of attributes was observed over a 2-year period (19900—1992), including persistence, vigour, productivity, palatability, morphology, and characteristics related to seed production. Accessions were initially culled on the basis of their persistence. Data for a range of attributes were separately analysed using pattern analysis to provide a broad overview of the performance and characteristics of the remaining accessions. A number of selection criteria were applied which resulted in selection of a promising group of 20 accessions (12 species from 8 genera). The promising group of accessions will be evaluated further at field sites typical of hilly landscapes in the 500mp;mdash;600 mm rainfall zone of south-eastern Australia.

The influence of buffel grass (Cenchrus ciliaris) on biodiversity in an arid Australian landscape

2009 ◽  
Vol 31 (3) ◽  
pp. 307 ◽  
Author(s):  
A. Smyth ◽  
M. Friedel ◽  
C. O'Malley
Keyword(s):  
Community Dynamics ◽  
Functional Group ◽  
Ground Vegetation ◽  
Cenchrus Ciliaris ◽  
Native Flora ◽  
Buffel Grass ◽  
Hot Climate ◽  
Environmental Weed ◽  
Grazing Lands ◽  
Land Types

Buffel grass [Cenchrus ciliaris L. syn. Pennisetum ciliare (L.) Link] is an exotic species that has been widely planted in Australian arid and semi-arid grazing lands, and has become an important resource for livestock. It establishes readily and has expanded into such a diversity of land types beyond grazing lands that it is also regarded as a serious environmental weed. Although there is an abundance of literature on the production benefits of buffel grass, there is relatively little about its influence on native flora and fauna in arid Australia, particularly when its cover levels are low. This study attempted to clarify the influence of buffel grass and environmental patterns on the occurrence of ground vegetation, birds, reptiles and ants in a gneissic hill habitat in central Australia where buffel grass has encroached. Despite poor conditions for growth, we were able to distinguish the influence of buffel grass from that of other variables like overstorey cover, soil pH, fire and transect orientation. Cover of buffel grass did not exceed ~20% but it still accounted for a small amount of the variation in the composition of ground vegetation and birds, and of the ‘ground-dwelling’ bird guild and the ‘hot climate specialist’ functional group of ants. There were insufficient reptiles for analysis. We conclude that, even when cover is low, buffel grass can have a detectable influence on some aspects of community dynamics. Given the evidence from published literature and from this study, we expect the influence of buffel grass on the diversity of native flora and fauna to increase, particularly if buffel grass expands into land types previously thought unsuited to its environmental needs.

scholarly journals Research on the Influence of Organic Fertilizing and Mulching on Productivity and Phytodiversity on Oligotrophic Grasslands

2013 ◽  
Vol 70 (1) ◽  
pp. 47-54
Author(s):  
Ágnes BALáZSI ◽  
Ioan ROTAR ◽  
Florin PÄ‚CURAR ◽  
Roxana VIDICAN ◽  
Anca BOGDAN
Keyword(s):  
Dry Matter ◽  
Floristic Composition ◽  
Organic Fertilizers ◽  
Festuca Rubra ◽  
Floristic Diversity ◽  
Dry Matter Yield ◽  
Agrostis Capillaris ◽  
Time Intervals ◽  
Apuseni Mountains ◽  
Grassland Type

Organic fertilizers have an influence on the floristic composition of grasslands. Fertilizing with manure favours the phytodiversity of grasslands. The objective of the study was to follow the influence of mulching and organic fertilizing in small quantities and at various time intervals upon dry matter yield and phytodiversity of Agrostis capillaris L. - Festuca rubra L. grassland type in the Apuseni Mountains. Seven treatments  ( control  ( mowed 1/year ) ; mulch 1/year; mulch 1/year + 5 t/ha manure /year; mulch 1/year + 5 t/ha manure/2 years; mulch 1/year + 10 t/ha manure/2 years; mulch 1/year + 10 t/ha manure/3 years; abandonment )  were evaluated experimentally. Organic fertilizing in low quantities could be a way to maintain the floristic diversity of oligotrophic grasslands in Apuseni Mountains.

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