Can bare ground cover server as a surrogate for plant biodiversity in grazed tropical woodlands?

2009 ◽  
Vol 31 (1) ◽  
pp. 103 ◽  
Author(s):  
Juliana McCosker ◽  
John Rolfe ◽  
Rod Fensham
Keyword(s):  
Ground Cover ◽  
Plant Species Richness ◽  
Perennial Grasses ◽  
Individual Species ◽  
Bare Ground ◽  
Themeda Triandra ◽  
Land Type ◽  
Eastern Australia ◽  
High Level ◽  
Tropical Woodlands

A bare ground index derived by remote sensing would provide a rapid methodology for assessing the biodiversity condition of an ecosystem, providing that ground cover is a satisfactory correlate with key biodiversity attributes. The relationship between plant species richness and the abundance of individual species was examined in relation to ground cover within silver-leaved ironbark (Eucalyptus melanophloia F. Muell.) woodlands in the Desert Uplands bioregion of north-eastern Australia. There was significant correlation between the bare ground index and ground cover and biomass measurements. Twenty-four species, including the perennial grasses Sehima nervosum (Rottler) Stapf, Themeda triandra Forssk. and Bothriocloa ewartiana (Domin) C.E. Hubb., were significantly and negatively correlated with bare ground. Scleroleana birchii (F. Muell.) Domin and Sida fibulifera Lindl.displayed significant positive relationships with increasing bare ground, and where abundant indicate heavy grazing in this land type. The study suggests that satellite-derived data does provide a meaningful methodology for assessing vegetation condition although it is strongly associated with seasonal conditions, but is only useful in relation to the regional average for a land type. The findings suggest that plant diversity is maintained at a relatively high level throughout most of these woodlands in the Desert Uplands.

Grazing pressure impacts on two Aristida/Bothriochloa native pasture communities of central Queensland

2017 ◽  
Vol 39 (3) ◽  
pp. 227 ◽  
Author(s):  
Trevor J. Hall ◽  
Paul Jones ◽  
Richard G. Silcock ◽  
Piet G. Filet
Keyword(s):  
Ground Cover ◽  
Predictive Modelling ◽  
Grazing Pressure ◽  
Total Contribution ◽  
Themeda Triandra ◽  
Crown Cover ◽  
Economic Production ◽  
Eastern Australia ◽  
Negative Effect ◽  
Native Pastures

Managing native pastures for sustainable and economic production requires a good understanding of grazing effects on pasture dynamics. The Aristida/Bothriochloa pastures of north-eastern Australia are important for cattle production but little data on grazing pressure impacts on pastures are available to guide management decisions of producers, for land management education programs, or for predictive modelling. To address this deficiency, four different continuous grazing intensities were imposed on woodland communities over 7 or 8 years at two sites: a Eucalyptus populnea (poplar box) and a E. melanophloia (silver-leaved ironbark) community. Both sites had replicated paddocks grazed at a low, medium or high grazing pressure by +/− tree killing using herbicide (12 paddocks), and 12 ungrazed (nil grazing pressure) 1-ha plots subjected to the same tree-killing contrasts. Grazed paddock areas were fixed and varied between 3.5 and 21.5 ha. Differential grazing pressures were reset each autumn, by adjusting cattle numbers to consume over the next year the equivalent of 0%, 25%, 50% or 75% of the standing pasture mass available. Pasture grasses suitable as indicators of grazing pressure were identified for both communities. Under low grazing pressure, Themeda triandra (kangaroo grass) was the only desirable grass to show a significant increase in total contribution over time at both sites, although Dichanthium sericeum (Queensland bluegrass) also increased its contribution at the poplar box site. Chloris species increased their contribution as grazing pressure increased. The proportion of less palatable Aristida spp. (wiregrasses) in the pasture was not affected by high grazing pressure, although they increased at low grazing pressure in the poplar box community. There were no consistent changes in native legumes or weedy forb species to any treatment. Increasing grazing pressure had a greater negative effect on pasture mass, ground cover and pasture crown cover area than on changing species composition. Most changes in composition due to grazing pressure were smaller than those associated with variable seasonal rainfall, and were greater in the poplar box community. In above-average rainfall years grazing up to 50% of autumn standing pasture mass had no detrimental effect on composition in treeless poplar box country in the short term. The pastures remained stable or improved in both communities when grazing pressure was set annually to utilise 25% of the standing autumn forage.

scholarly journals Dynamics of the ground layer communities of tropical eucalypt woodlands of northern Queensland

2021 ◽  
Vol 69 (2) ◽  
pp. 85
Author(s):  
V. J. Neldner ◽  
D. W. Butler
Keyword(s):  
Species Composition ◽  
Plant Species ◽  
Species Abundance ◽  
Perennial Grasses ◽  
Ground Layer ◽  
Plant Species Composition ◽  
Themeda Triandra ◽  
Annual Variability ◽  
Eastern Australia ◽  
Directional Change

This paper presents insights from long-term monitoring into the dynamics of savanna plant species composition, specifically on the ground layer. Key questions are (1) how much variation is there from year to year in plant species abundance and composition? And (2) is there evidence of directional change in community composition? Five sites were located near Mareeba, north-eastern Australia, and sampled 18 times with fixed 500-m2 plots at the annual peak of plant species richness over 23 years. The sites were located in eucalypt communities across an altitudinal range of 460 m. Sampling involved systematic searching of all plant species visible above ground. The results show variation from year to year among satellite herbaceous species, with more than 50% of grasses and forbs observed at a given site only being detected at half or fewer of the 18 samplings. Herbaceous composition did not show clear signs of directional change relative to inter-annual variability. Over the 23 years, there were three very dry periods and 4 very wet years. Rainfall variation affected total cover more than plant species composition or richness. Several fires and episodes of grazing affected ground cover but did not have a lasting impact on cover or diversity. The cover and composition of the ground layer is consistently dominated by the core perennial grasses Themeda triandra Forssk. and Heteropogon triticeus (R.Br.) Stapf, with many species collectively contributing minimally to the overall cover but significantly to richness. Many herb species are persistent long-lived perennials which do not appear above ground every year. The number of naturalised plants in the ground layer was consistently low. Overall, the ground layer communities appear to be very stable in these woodlands that have been burnt 3–5 times in 23 years. High inter-annual variability of subdominant species is consistent with other studies, and emphasises the need for replication in time in ecological sampling.

Managing saffron thistle in pastures with strategic grazing

2002 ◽  
Vol 24 (2) ◽  
pp. 313 ◽  
Author(s):  
B. S. Grace ◽  
R. D. B. Whalley ◽  
A. W. Sheppard ◽  
B. M. Sindel
Keyword(s):  
Late Spring ◽  
Perennial Grasses ◽  
Control Measures ◽  
Grazing Management ◽  
Bare Ground ◽  
Grazing Land ◽  
Continuous Grazing ◽  
Eastern Australia ◽  
Stocking Rates

Saffron thistle (Carthamus lanatus L.) is a widespread and troublesome weed in grazing land throughout much of eastern Australia. Conventional control measures are not feasible in much of this area, so the prospect for controlling saffron thistle through strategic grazing with sheep was investigated. By sowing seeds, and counting seedlings that emerged, we found that as little as 2 cm of pasture cover reduced the number of seedlings that emerged by 96% compared with bare ground. Grazing experiments showed that the survival of saffron thistle rosettes was reduced by 12% in plots that were strategically rested for one month in autumn, followed by grazing at high stocking rates. Grazing in late spring, when plants produced flowering stems, killed 20% of thistles before they set seed. A comparison of thistle density and pasture composition on farms that practice strategic grazing with neighbouring farms that used continuous grazing supported these results. Pastures had few thistles when perennial grasses accounted for over 35% of groundcover. We conclude that grazing management can help control saffron thistle.

A Multivariate Growth-form Analysis of Grassland and Forest Forbs in South-eastern Australia

1997 ◽  
Vol 45 (4) ◽  
pp. 691 ◽  
Author(s):  
Ian D. Lunt
Keyword(s):  
Growth Form ◽  
Ground Cover ◽  
Themeda Triandra ◽  
Form Analysis ◽  
Relative Paucity ◽  
Native Grasslands ◽  
Forest Sites ◽  
Eastern Australia ◽  
Forest Remnants ◽  
Species Groups

The growth-form composition of grazed and unburnt, grassy forest remnants and ungrazed, frequently burnt, anthropogenic native grasslands in Gippsland, Victoria were compared, using a multivariate, clustering analysis of the growth-form and life-form attributes of 53 forb species. Groups comprising (1) annual forbs, (2) clambering, repent and decumbent perennials, and (3) rosette perennials and rhizomic ground-cover forbs occurred in significantly more forest than grassland quadrats. One group, mostly containing tall erect geophytes with linear basal leaves, occurred in significantly more grassland than forest quadrats. Grassland quadrats contained significantly more tall forbs (> 20 cm) than forest quadrats, whilst forest quadrats contained significantly more forbs of short to medium height (< 20 cm). There was a significant, positive correlation between plant height and frequency of occurrence in grassland quadrats (rs = 0.58, P < 0.001), and a significant, although weak, negative correlation in forest quadrats (rs = -0.29, P < 0.05). Short forbs are likely to have been depleted from grassland sites owing to competition from the dominant tussock grass, Themeda triandra Forsskal. By contrast, ground cover in forest sites is of relatively low stature, biomass and cover, allowing short forbs to persist. The relative paucity of tall forbs from forest remnants is suspected to be at least partly due to intensive stock grazing in the past.

Effects of nitrogen and phosphorus on vegetation dynamics of a degraded native grassland in semi-arid south-eastern Australia

2011 ◽  
Vol 33 (1) ◽  
pp. 87 ◽  
Author(s):  
R. B. Hacker ◽  
I. D. Toole ◽  
G. J. Melville
Keyword(s):  
Vegetation Dynamics ◽  
Plant Density ◽  
Perennial Grass ◽  
Ground Cover ◽  
Perennial Grasses ◽  
Grass Species ◽  
Nitrogen And Phosphorus ◽  
Mineral N ◽  
Eastern Australia ◽  
Semi Arid

The roles of nitrogen (N) and phosphorus (P) in controlling vegetation transitions in a degraded semi-arid grassland were investigated in a factorial experiment that combined two initial levels of perennial plant density (low and high), three levels of N (N+, N0 and N–) and two levels of P (P+ and P0). Increased levels of both N and P were achieved by fertiliser addition while sucrose was used to reduce the level of N. Vegetation dynamics were driven primarily by soil N rather than P. Addition of sucrose, which was inferred to result in the immobilisation of mineral N, reduced the growth of annual species and facilitated the establishment and growth of native perennial grasses. Addition of P generally had no significant effect on dry matter production, either in total or for species grouped as forbs, annual grasses and perennial grasses, or on recruitment and mortality of perennial grasses. However, at some times of observation addition of P increased ground cover and/or the basal circumference of some perennial grass species. Basal circumference for Enteropogon acicularis was also increased by addition of N. Soil biological activity, measured by decomposition of cotton strips, was increased by addition of N, which maintained vegetation in an annual-dominated condition, and was not affected by addition of P. Carbon addition has the potential to assist restoration of this grassland. However, the capacity of some native grass species to respond to increased fertility suggests that once restoration is achieved some increase in fertility may be beneficial for pastoral production.

Studies of competition between Nassella trichotoma (Nees) Hack. ex Arechav. (serrated tussock) and native pastures. 2. Seedling responses

2008 ◽  
Vol 59 (3) ◽  
pp. 237 ◽  
Author(s):  
W. B. Badgery ◽  
D. R. Kemp ◽  
D. L. Michalk ◽  
W. McG. King
Keyword(s):  
Dry Matter ◽  
Seedling Recruitment ◽  
Perennial Grass ◽  
Ground Cover ◽  
Perennial Grasses ◽  
Native Grass ◽  
Eastern Australia ◽  
Native Pastures ◽  
Grass Weed ◽  
Native Perennial Grass

Native perennial grass competition can substantially reduce the invasion of Nassella trichotoma (serrated tussock), a major perennial grass weed problem in south-eastern Australia. This paper reports on a field experiment that investigated the recruitment of N. trichotoma seedlings, and determined what level of native grass competition was needed to prevent establishment in the central-west of NSW. Grasslands that maintained >2 t dry matter (DM)/ha and 100% ground cover (measured in spring) prevented N. trichotoma seedling recruitment. Relatively small amounts of perennial grass (>0.5 t DM/ha measured in spring) resulted in mortality of N. trichotoma seedlings that had recruited earlier in the year, through the next summer. Flupropanate also markedly reduced native perennial grasses and substantially increased N. trichotoma seedling establishment 12 months after application. Rotational grazing to maintain adequate levels of DM was an important management tactic that prevented N. trichotoma establishment and survival.

Effects of nitrogen and phosphorus fertilizers and gypsum on a Danthonia caespitosa-Stipa variabilis grassland. 1. Response to fertilizer application over four successive years

1978 ◽  
Vol 18 (91) ◽  
pp. 253 ◽  
Author(s):  
GJ Tupper
Keyword(s):  
Summer Rainfall ◽  
Fertilizer Application ◽  
Perennial Grasses ◽  
Annual Rainfall ◽  
Individual Species ◽  
Forage Production ◽  
Nitrogen And Phosphorus ◽  
Eastern Australia ◽  
Phosphorus Fertilizers ◽  
Minimum Requirements

The effect of nitrogen and phosphorus fertilizers and gypsum was assessed over four years on a Danthonia caespitosa-Stipa variabilis grassland, growing on the semi-arid Riverine Plain in south-eastern Australia. Fertilizers were applied annually and gypsum once only. The treatments were combined factorially. Seasonal production of total dry matter and individual species, and nitrogen and phosphorus contents of the plant tops, were measured. Forage production increased in response to the additives in years in which the annual rainfall varied from well below to near average. They accentuated the normal pattern of a spring peak, but also gave lesser increases in production in winter and autumn. Summer production was not measured because of the absence of effective summer rainfall. Nitrogen and phosphorus fertilizers and gypsum all contributed to the increased production, and the combination of the three additives produced the greatest yield. Over all seasons the yield of grassland treated with nitrogen plus phosphorus plus gypsum averaged 250 per cent of the control, or approximately 1500 kg ha-1. The main contributors to increases in yield were D. caespitosa, S. variabilis, annual herbs, and legumes. The perennial grasses were particularly favoured by nitrogen fertilizer whereas the yield of legumes was suppressed. The yield of legumes increased greatly in response to phosphorus fertilizer. With the exception of two species, all plants which increased in yield are acceptable to sheep. Nitrogen and phosphorus contents were above the minimum requirements for domestic herbivores.

Medusahead Control with Fall- and Spring-Applied Herbicides on Northern Utah Foothills

2005 ◽  
Vol 19 (3) ◽  
pp. 653-658 ◽  
Author(s):  
Thomas A. Monaco ◽  
Travis M. Osmond ◽  
Steven A. Dewey
Keyword(s):  
Perennial Grass ◽  
Ground Cover ◽  
Perennial Grasses ◽  
Primary Concern ◽  
Annual Grass ◽  
Bare Ground ◽  
Prescribed Burns ◽  
Northern Utah ◽  
Winter Annual ◽  
Second Year

Medusahead is an aggressive, nonnative, winter annual grass that infests rangelands in the western United States. Its ability to rapidly spread, outcompete native vegetation, and destroy forage potential is a primary concern for landowners and land managers exposed to this weed. Prescribed burns were conducted at a low- and high-litter site in northern Utah prior to conducting experiments to evaluate the effects of fall and spring applications of sulfometuron at 39 or 79 g ai/ha and imazapic at 70 or 140 g ai/ha on medusahead and associated perennial grasses, annual and perennial forbs, and bare ground cover. Large differences in pretreatment medusahead litter between the sites resulted in less surface area burning at the low-litter site (∼10%) compared to the high-litter site (∼80%). Higher herbicide rates significantly increased medusahead control and bare ground cover; however, this rate affect largely depended on site, season, and herbicide. The low- and high-litter sites did not differ significantly in perennial grass cover 2 yr after burning. Annual forb cover was greater, but perennial forb cover was lower at the low-litter site compared to the high-litter site. Several treatment combinations were identified as having the potential to maintain greater than 50% medusahead control in the second year after herbicide applications. These results collectively demonstrate that potential exists to successfully control medusahead and produce a window of opportunity to reintroduce a greater abundance of perennial species back into the plant community via seeding.

Floristic composition and pasture condition of Aristida/Bothriochloa pastures in central Queensland. II. Soil and pasture condition interactions

2015 ◽  
Vol 37 (2) ◽  
pp. 217
Author(s):  
R. G. Silcock ◽  
T. J. Hall ◽  
P. G. Filet ◽  
A. M. Kelly ◽  
D. Osten ◽  
...  
Keyword(s):  
Soil Type ◽  
Plant Density ◽  
Surface Condition ◽  
Good Condition ◽  
Basal Area ◽  
Ground Cover ◽  
Perennial Grasses ◽  
Tree Cover ◽  
Themeda Triandra ◽  
Heteropogon Contortus

Sustainable management of native pastures requires an understanding of what the bounds of pasture composition, cover and soil surface condition are for healthy pastoral landscapes to persist. A survey of 107 Aristida/Bothriochloa pasture sites in inland central Queensland was conducted. The sites were chosen for their current diversity of tree cover, apparent pasture condition and soil type to assist in setting more objective bounds on condition ‘states’ in such pastures. Assessors’ estimates of pasture condition were strongly correlated with herbage mass (r = 0.57) and projected ground cover (r = 0. 58), and moderately correlated with pasture crown cover (r = 0.35) and tree basal area (r = 0.32). Pasture condition was not correlated with pasture plant density or the frequency of simple guilds of pasture species. The soil type of Aristida/Bothriochloa pasture communities was generally hard-setting, low in cryptogam cover but moderately covered with litter and projected ground cover (30–50%). There was no correlation between projected ground cover of pasture and estimated ground-level cover of plant crowns. Tree basal area was correlated with broad categories of soil type, probably because greater tree clearing has occurred on the more fertile, heavy-textured clay soils. Of the main perennial grasses, some showed strong soil preferences, for example Tripogon loliiformis for hard-setting soils and Dichanthium sericeum for clays. Common species, such as Chrysopogon fallax and Heteropogon contortus, had no strong soil preference. Wiregrasses (Aristida spp.) tended to be uncommon at both ends of the estimated pasture condition scale whereas H. contortus was far more common in pastures in good condition. Sedges (Cyperaceae) were common on all soil types and for all pasture condition ratings. Plants identified as increaser species were Tragus australianus, daisies (Asteraceae) and potentially toxic herbaceous legumes such as Indigofera spp. and Crotalaria spp. Pasture condition could not be reliably predicted based on the abundance of a single species or taxon but there may be scope for using integrated data for four to five ecologically contrasting plants such as Themeda triandra with daisies, T. loliiformis and flannel weeds (Malvaceae).

CITY PARK AS A NATURAL-ANTHROPOGENIC OBJECT (ON THE EXAMPLE OF THE PARK OF THE 50th ANNIVERSARY OF VLKSM IN THE CITY OF YEKATERINBURG)

2021 ◽  
pp. 133-140
Author(s):  
L. I. ATKINA ◽  
◽  
L. V. BULATOVA ◽  
L. P. ABRAMOVA
Keyword(s):  
Soil Cover ◽  
Negative Impact ◽  
50Th Anniversary ◽  
Ground Cover ◽  
Peat Bogs ◽  
Anthropogenic Transformation ◽  
History Of ◽  
High Level ◽  
The City ◽  
City Park

Based on a comprehensive assessment of the state of the park landscape, the level of its anthropogenic transformation is determined, which is necessary to identify the potential for restoring the natural biodiversity of the object. It is reported that the plantations and soil cover of the park of the 50th anniversary of VLKSM are very heterogeneous; they reflect the history of park establishment. The soil cover consists of three main types: sod, bog and urbanozem. It should be stressed that the best preserved part of the park is the plot with boggy soils around the pond. Herbaceous plants growing on the plot are very similar to the species composition of the ground cover of overgrown peat bogs. Over the 40 years since the foundation of the park, a high level of pollutants has been accumulated in the soil, which allows us to state that the negative impact occurs constantly. Consequently, the existing plantings are insufficient to protect visitors from vehicle emissions from the roads along Yasnaya and Shaumyana streets. There are enough natural elements in the park of the 50th anniversary of VLKSM; this should be taken into account in its redevelopment. There is an opportunity to restore the reservoir and return the plantings to their natural appearance. It is proposed to add elements of landscape decoration in the park.

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