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.

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.

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.

scholarly journals Impacts of habitat fragmentation on genetic diversity in a tropical forest butterfly on Borneo

2007 ◽  
Vol 23 (6) ◽  
pp. 623-634 ◽  
Author(s):  
Suzan Benedick ◽  
Thomas A. White ◽  
Jeremy B. Searle ◽  
Keith C. Hamer ◽  
Nazirah Mustaffa ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Time Delay ◽  
Habitat Fragmentation ◽  
Forest Fragmentation ◽  
Haplotype Diversity ◽  
Genetic Erosion ◽  
Forest Sites ◽  
Increased Risk ◽  
Forest Remnants ◽  
Mtdna Diversity

Many areas of rain forest now exist as habitat fragments, and understanding the impacts of fragmentation is important for determining the viability of populations within forest remnants. We investigated impacts of forest fragmentation on genetic diversity in the butterfly Mycalesis orseis (Satyrinae) in Sabah (Malaysian Borneo). We investigated mtDNA diversity in 90 individuals from ten forest sites typical of the sizes of forest remnants that currently exist in the region. Nucleotide diversity declined with increasing isolation of remnants, but there was no effect of remnant size or population size, and haplotype diversity was similar among sites. Thus, approximately 50 y after forest fragmentation, few changes in genetic diversity were apparent and remnants apparently supported genetically viable populations of this butterfly. Many studies have shown that responses of species to habitat fragmentation usually follow a time delay, and so we developed a Monte Carlo simulation model to investigate changes in genetic diversity over time in small remnants. Model output indicated a substantial time delay (> 100 y) between fragmentation and genetic erosion, suggesting that, in the smallest study remnants, an increased risk of extinction from reduced genetic diversity is likely in the longer term.

scholarly journals Species composition of climbers in seasonal semideciduous forest fragments of Southeastern Brazil

2009 ◽  
Vol 9 (4) ◽  
pp. 175-188 ◽  
Author(s):  
Karin dos Santos ◽  
Luiza Sumiko Kinoshita ◽  
Andréia Alves Rezende
Keyword(s):  
Floristic Composition ◽  
Southeastern Brazil ◽  
Forest Site ◽  
Forest Fragments ◽  
Semideciduous Forest ◽  
Number Of Species ◽  
Forest Sites ◽  
Forest Remnants ◽  
Mean Similarity ◽  
Made In

In this study we evaluated floristic composition patterns of communities of climbers within ten inventories carried out in semideciduous forest fragments of southeastern Brazil. One of the inventories is original, being carried out for the present study in Ribeirão Cachoeira forest, Campinas, São Paulo State, Southeastern Brazil. This inventory was then pooled together to other nine climbers' inventories made in other forests of Southeastern Brazil to form a data base, which was examined regarding species richness, similarity, species distribution and climbing methods. The total number of species obtained was 355, belonging to 145 genera and 43 families. The ten most diverse families Bignoniaceae (45 species), Fabaceae (42), Malpighiaceae (36), Asteraceae (31), Apocynaceae (29), Sapindaceae (28), Convolvulaceae (21), Cucurbitaceae (14), Passifloraceae (10), and Euphorbiaceae (8) contributed to 74.4% of the total number of species recorded. The commonest climbing method in the studied sites was main stem or branch twining, accounting for 178 species or 50.1% of the total, the second commonest was tendril climbing (121 species, 34.1%), and the least, scrambling (56 species, 15.8%). We found a high percentage of exclusive species i.e., those occurring in only one forest site, which accounted for 49.3% of the total recorded. The mean similarity among forest sites (30%) may be considered low. The climbing species contribution to the total wood plant richness recorded on the forests sites was very high in some of the sites (up to 52.5%). These results indicated the importance of climber communities to plant diversity for semideciduous forests in Southeastern Brazil, enhancing the regional diversity and the conservation value of these forest remnants.

TEMPERATURE AND EVAPORATION AT AND NEAR GROUND LEVEL ON CERTAIN FOREST SITES

1954 ◽  
Vol 32 (6) ◽  
pp. 760-783 ◽  
Author(s):  
Olli Vaartaja
Keyword(s):  
Surface Soil ◽  
Ground Cover ◽  
Ground Level ◽  
Root Competition ◽  
Diurnal Fluctuation ◽  
Large Temperature ◽  
Ground Vegetation ◽  
Forest Sites ◽  
Maximum Temperatures ◽  
General Climate

Microclimate, especially temperature extremes, was studied on various plots of pine and spruce sites in Finland. Thermoelement measurements were made on clear, calm summer days. Comparisons showed that the climate of the exposed sites varied greatly from that of the sites with protective ground vegetation or canopy. Very large temperature differences between the sites existed at ground-level and moderately large differences at the 5 and 20 cm. levels. At exposed sites a temperature range of 57 °C. in 24 hr. was recorded in sandy surface soil, and still larger ranges seemed probable. Extreme diurnal fluctuation in temperature is evidently not closely correlated with general climate; it is favored by dryness of the soil and presence of ground cover, such as humus and fine litter, with low thermal conductivity. Maximum temperatures of 50° to 70 °C, are considered of normal occurrence in thin surface soil at exposed sites in large areas of northern coniferous forests. At the same time, maximum temperatures may remain from 9° to 13 °C. under the protection of canopy and surface cover, and night minima may be below 0 °C. in thin surface soil. A negative correlation was found between evaporation rate and drought injuries of plants on dry sites. Root competition was a more important factor to plants than evaporation conditions, at least as shown by the measurements from large vessels.

Seed bank dynamics of Acacia farnesiana (L.) Willd. and its encroachment potential in sub-humid grasslands of eastern Australia

2013 ◽  
Vol 35 (4) ◽  
pp. 427 ◽  
Author(s):  
H. Ibrahim Erkovan ◽  
Peter J. Clarke ◽  
Ralph D. B. Whalley
Keyword(s):  
Seed Dormancy ◽  
Seed Bank ◽  
Reproductive Output ◽  
Grazing Pressure ◽  
Long Distance ◽  
Acacia Farnesiana ◽  
Native Grasslands ◽  
Seed Bank Dynamics ◽  
Eastern Australia ◽  
Abiotic And Biotic Factors

Shrub encroachment involves abiotic and biotic factors that regulate demographic factors influencing seed production, storage, germination, and subsequent recruitment. In the rangelands of semi-arid and arid Australia, the thorny acacia, Acacia farnesiana (L.) Willd., is apparently encroaching into grasslands and changing the structure, composition, and functioning of native grasslands. The potential for A. farnesiana to expand rapidly in response to changes in land use was examined by quantifying the reproductive output, dispersal, seed-bank density, and germination of seeds of A. farnesiana. Even in the absence of high grazing pressure, low numbers of seeds were produced and these were mainly locally dispersed, although long-distance dispersal via floods could occur. Pre-dispersal seed predation is likely to reduce the seed output, and despite strong physical seed dormancy, soil-stored seed banks were not large. Seed dormancy is broken by scarification but not strongly synergistically with fire or by fire alone, and fire may have a small effect on recruitment. Hence, pulse recruitment seems unlikely given the match between seedling densities and seed-bank density. These patterns suggest that A. farnesiana is unlikely to encroach rapidly into grasslands unless there is widespread landscape disturbance that triggers broad-scale dispersal, such as floods, and or physical scarification of seed.

Les coupes forestières dans les pessières à lichens: effets sur la croissance et la régénération des conifères (Whapmagoostui, Québec subarctique)

1988 ◽  
Vol 66 (6) ◽  
pp. 1013-1020 ◽  
Author(s):  
Ann Delwaide ◽  
Louise Filion
Keyword(s):  
Picea Glauca ◽  
Radial Growth ◽  
Growth Form ◽  
Black Spruce ◽  
Ground Cover ◽  
Climatic Conditions ◽  
Hudson Bay ◽  
Clear Cutting ◽  
Physical Conditions ◽  
Tree Harvesting

In the Whapmagoostui area (east of Hudson Bay), tree harvesting by Crée Indians in lichen woodlands affects the form and the growth of surviving trees and also the forest population dynamics. A study of the growth form of white spruce (Picea glauca (Moench) Voss.) and black spruce (Picea mariana (Mill.) B.S.P.) that have been pruned shows the efficiency of a total traumatic reiteration process. After several years, the annual radial growth was equivalent to that recorded before pruning. In clear-cutting areas (more than 75% of trees removed), the increase in the radial growth of spared trees was 400 to 700%. The main factors that govern the success of regeneration in cutting areas are the rather small extension of the openings (<0.005 km2), the low intensity of tree harvesting (<75% of trees over 90% of the surface), the physical conditions of the lichenous ground cover and the abundance of the lignified debris after clearing vegetation, and the climatic conditions in the subsequent years.

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).

scholarly journals Phosphorus fertiliser management for pastures based on native grasses in south-eastern Australia

2019 ◽  
Vol 70 (12) ◽  
pp. 1044
Author(s):  
M. L. Mitchell ◽  
M. R. McCaskill ◽  
R. D. Armstrong
Keyword(s):  
Low Fertility ◽  
Grass Species ◽  
Soil Test ◽  
Native Grasses ◽  
Native Grass ◽  
Themeda Triandra ◽  
South Eastern ◽  
Eastern Australia ◽  
Native Pasture ◽  
South Eastern Australia

Approximately 3.1 Mha (22%) of the agricultural area of south-eastern Australia can be classified as native pasture. There is the assumption that, owing to the widespread occurrence of low-fertility soils in Australia, native grass species do not respond to increased phosphorus (P) fertility. Currently, there are no industry recommendations of target soil-test P values for native-grass-based pastures. This paper reviews the responses of perennial native pasture species endemic to south-eastern Australia to P application in controlled environments, surveys, replicated experiments and paired-paddock trials. Eighty-seven site-years of trial data where different levels of P were applied, conducted over the last two decades, on native-based pastures in south-eastern Australia are reviewed. Data indicate that application of P fertilisers to native grass pastures can increase dry matter (DM) production and maintain pasture stability. However, minimum targets for herbage mass (800 kg DM/ha) and groundcover (80%) are required to ensure persistence of perennial native grasses. Stocking rates also need to match carrying capacity of the pasture. Based on previous research, we recommend target soil-test (Olsen; 0–10 cm) P levels for fertility-tolerant native grass pastures, based on Microlaena stipoides, Rytidosperma caespitosum, R. fulvum, R. richardsonii, R. duttonianum and R. racemosum, of 10–13 mg/kg, whereas for pastures based on fertility-intolerant species such as Themeda triandra, lower levels of &lt;6 mg/kg are required to ensure botanical stability.

Description of three new velvet geckos (Diplodactylidae: Oedura) from inland eastern Australia, and redescription of Oedura monilis De Vis

Zootaxa ◽  
2019 ◽  
Vol 4683 (2) ◽  
pp. 242-270
Author(s):  
CONRAD J. HOSKIN
Keyword(s):  
Habitat Type ◽  
Original Description ◽  
Junior Synonym ◽  
Colour Pattern ◽  
Widespread Species ◽  
Northern Half ◽  
Eastern Australia ◽  
Forest Remnants ◽  
Taxonomic Uncertainty ◽  
Threatened Habitat

Inland eastern Australia has a complex array of habitats, driven by variation in topography, geology and moisture. This broad region is relatively poorly surveyed compared to coastal eastern Australia and likely contains significant numbers of undescribed reptiles. Oedura monilis is found through much of this region but has been shrouded in taxonomic uncertainty since its original description. Here I assess variation across the range of ‘O. monilis’ and show that it consists of two species: a widespread species in the northern half of the range and a widespread species in the southern half of the range. These two species are readily diagnosed by colour pattern and aspects of shape and scalation. I show that the name O. monilis applies to the northern species. I also show that the name O. attenboroughi Wells & Wellington applies to the northern populations, making it a junior synonym of O. monilis. I describe the southern widespread species as Oedura elegans sp. nov.. I also describe two new, highly localised species from inland eastern Queensland that are allied to O. monilis: Oedura picta sp. nov. from a rocky range in the Moranbah–Dysart region, and Oedura lineata sp. nov. from brigalow forest remnants in the Arcadia Valley. These two species are distinct for colour pattern and aspects of size, shape and scalation. Oedura lineata sp. nov. has a very small and fragmented range, and is restricted to a highly threatened habitat type. It therefore warrants conservation attention. I also provide more detailed diagnoses for O. coggeri Bustard and O. tryoni De Vis, and demonstrate that the name O. ocellata Boulenger is a junior synonym of O. tryoni. 

Sign in / Sign up

Export Citation Format

Share Document