Prolonged isolation and persistence of a common endemic on granite outcrops in both mesic and semi-arid environments in south-western Australia

2014 ◽  
Vol 41 (11) ◽  
pp. 2032-2044 ◽  
Author(s):  
Sarah-Louise Tapper ◽  
Margaret Byrne ◽  
Colin J. Yates ◽  
Gunnar Keppel ◽  
Stephen D. Hopper ◽  
...  
Keyword(s):  
Western Australia ◽  
Arid Environments ◽  
Granite Outcrops ◽  
Semi Arid

scholarly journals A hydrological framework for persistent river pools in semi-arid environments

2020 ◽  
Author(s):  
Sarah A. Bourke ◽  
Margaret Shanafield ◽  
Paul Hedley ◽  
Shawan Dogramaci
Keyword(s):  
Western Australia ◽  
Groundwater Discharge ◽  
Geological Mapping ◽  
Diagnostic Tools ◽  
Arid Environments ◽  
Hydrogeological Characteristics ◽  
Through Flow ◽  
Bedrock Aquifers ◽  
North Western ◽  
Semi Arid

Abstract. Persistent surface water pools along non-perennial rivers represent an important water resource for the plants, animals, and humans that inhabit semi-arid regions. While ecological studies of these features are not uncommon, these are rarely accompanied by a rigorous examination of the hydrological and hydrogeological characteristics that create or support the pools. Here we present an overarching framework for understanding the hydrology of persistent pools based on data from 22 pools in the Hamersley Basin in Western Australia. Three dominant mechanisms that control the occurrence of persistent pools have been identified; perched pools, through flow pools and groundwater discharge pools. Groundwater discharge pools are further categorized into those that are present because of a geological contact or barrier, and those that are controlled by topography. A suite of diagnostic tools (including geological mapping, hydraulic data and hydrochemical surveys) is generally required to identify the mechanism supporting persistent pools. Perched pools are sensitive to climate variability but their persistence is largely independent of groundwater withdrawals. Water fluxes to pools from alluvial and bedrock aquifers can vary seasonally and resolving these inputs is generally non-trivial. The susceptibility of through-flow and groundwater discharge pools to climate variations and groundwater withdrawals depends on the mechanism of pool persistence and the spatial distribution of stressors relative to the pool. Although this framework was developed in the context of north-western Australia, this framework can also be applied to pools and springs found along non-perennial rivers around the world.

scholarly journals Evidence for convergent evolution among phylogenetically distant rare species of Tetratheca (Elaeocarpaceae, formerly Tremandraceae) from Western Australia

2007 ◽  
Vol 20 (2) ◽  
pp. 126 ◽  
Author(s):  
Ryonen Butcher ◽  
Margaret Byrne ◽  
Darren M. Crayn
Keyword(s):  
Western Australia ◽  
Rare Species ◽  
Cladistic Analysis ◽  
Geographic Area ◽  
Arid Environments ◽  
High Conservation ◽  
Superficial Similarity ◽  
Evolutionary Lineages ◽  
Semi Arid

Morphological and molecular investigations of taxon relationships among rare species of Tetratheca Sm. occurring near Koolyanobbing, Western Australia, have confirmed the distinctness of T. aphylla F.Muell., T. harperi F.Muell. and T. paynterae Alford and identified three new rare taxa from collections affiliated with T. aphylla and T. paynterae. The recognition of these taxa at specific and sub-specific ranks is based on their different degrees of morphological and molecular divergence, combined with geographic disjunction. Cladistic analysis of nrDNA internal transcribed spacer and cpDNA trnL-trnF sequences from a range of Tetratheca species from Western Australia and the eastern states indicates that T. aphylla, T. harperi and T. paynterae belong to three separate evolutionary lineages and that the endemism displayed among these taxa to small, disjunct ranges within the same geographic area, is a result of in situ speciation due to historical fragmentation. These results exemplify the extremely high conservation value of the Yilgarn banded ironstone ranges. The superficial similarity among the study taxa in having a ‘leafless’ habit can be seen to be adaptive convergence in response to the marginal and semi-arid environments in which they occur, and this character is highly homoplastic within the genus.

Ecotypic variation between and within two populations of Trifolium tomentosum (woolly clover) from Syria and Western Australia: its success as a colonising species

1999 ◽  
Vol 50 (8) ◽  
pp. 1443 ◽  
Author(s):  
Sarita Jane Bennett
Keyword(s):  
Western Australia ◽  
Function Analysis ◽  
Acid Soils ◽  
Arid Environment ◽  
Arid Environments ◽  
Alkaline Soils ◽  
Field Station ◽  
Ecotypic Variation ◽  
Site Variation ◽  
Semi Arid

Ecotypic variation was studied between and within populations of Trifolium tomentosum (woolly clover) using seed that was collected from 2 semi-arid environments: Tel Hadya, Syria, and Pingrup, Western Australia. The seed was collected from 64 subplots within a 40-m2 grid at each site and the material was grown at the University of Western Australia Field Station at Shenton Park, Perth. Fifteen morphological characters were scored and were analysed using analysis of variance, principal components analysis, and discriminant function analysis. Material from the 2 sites was separated using multivariate analysis, with the seed from Tel Hadya containing more within-site variation. It is suggested that the lack of within-site variation observed at Pingrup is the result of a number of factors: a limited amount of genetic diversity being present in the original introduced material, a preference of T. tomentosum for alkaline soils rather than the acid soils predominantly occurring in Western Australia, the harsh selection pressures present in a semi-arid environment, and a limited time for genotypes to adapt to specific micro-niches within each environment. The results are used to contribute to our understanding of the success of colonising species in semi-arid environments.

scholarly journals Exogenously Used 24-Epibrassinolide Promotes Drought Tolerance in Maize Hybrids by Improving Plant and Water Productivity in an Arid Environment

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 354
Author(s):  
El-Sayed M. Desoky ◽  
Elsayed Mansour ◽  
Mohamed M. A. Ali ◽  
Mohamed A. T. Yasin ◽  
Mohamed I. E. Abdul-Hamid ◽  
...  
Keyword(s):  
Drought Tolerance ◽  
Agronomic Traits ◽  
Water Productivity ◽  
Positive Association ◽  
Net Photosynthesis ◽  
Antioxidant Enzyme Activities ◽  
Severe Drought ◽  
Arid Environments ◽  
Maize Hybrids ◽  
Semi Arid

The influence of 24-epibrassinolide (EBR24), applied to leaves at a concentration of 5 μM, on plant physio-biochemistry and its reflection on crop water productivity (CWP) and other agronomic traits of six maize hybrids was field-evaluated under semi-arid conditions. Two levels of irrigation water deficiency (IWD) (moderate and severe droughts; 6000 and 3000 m3 water ha−1, respectively) were applied versus a control (well-watering; 9000 m3 water ha−1). IWD reduced the relative water content, membrane stability index, photosynthetic efficiency, stomatal conductance, and rates of transpiration and net photosynthesis. Conversely, antioxidant enzyme activities and osmolyte contents were significantly increased as a result of the increased malondialdehyde content and electrolyte leakage compared to the control. These negative influences of IWD led to a reduction in CWP and grain yield-related traits. However, EBR24 detoxified the IWD stress effects and enhanced all the above-mentioned parameters. The evaluated hybrids varied in drought tolerance; Giza-168 was the best under moderate drought, while Fine-276 was the best under severe drought. Under IWD, certain physiological traits exhibited a highly positive association with yield and yield-contributing traits or CWP. Thus, exogenously using EBR24 for these hybrids could be an effective approach to improve plant and water productivity under reduced available water in semi-arid environments.

Changing perceptions of the effect of plant phenolics on nutrient supply in the ruminant

1996 ◽  
Vol 47 (6) ◽  
pp. 829 ◽  
Author(s):  
JB Lowry ◽  
CS McSweeney ◽  
B Palmer
Keyword(s):  
Phenolic Compounds ◽  
Acute Toxicity ◽  
Protein Interactions ◽  
Nutrient Supply ◽  
Arid Environments ◽  
Plant Phenolics ◽  
Ruminant Nutrition ◽  
Forage Plants ◽  
Hydrolysable Tannins ◽  
Semi Arid

Mammalian metabolism of plant phenolics, initially studied in monogastric animals, gave an emphasis to their toxic and antinutrient effects. Subsequent studies in tropical ruminants and wild herbivores have highlighted the high levels than can occur in some diets and the extensive microbial modification and degradation that can occur in the tract. This paper reviews aspects of plant phenolics as they relate to ruminant nutrition in tropical or semi-arid environments in which some forage plants contain high levels of phenolic compounds. Effects range from occasional acute toxicity of hydrolysable tannins, to acetate-releasing microbial degradations that apparently enable certain phenolics to act as nutrients. The most important and complex effects are those due to tannin-protein interactions. Although these can clearly reduce feed intake, nutrient digestibilities, and protein availability, many of the interactions are still not understood. The diverse effects of plant phenolics on nutrient flow probably result from the balance between adverse effects on some organisms and the rate at which they are degraded or inactivated by other organisms, and improved animal performance can likely be obtained by manipulation of rumen microbial metabolism.

scholarly journals Modelling water utilization patterns in apple orchards with varying canopy sizes and different growth stages in semi-arid environments

2021 ◽  
Vol 283 ◽  
pp. 110051
Author(s):  
Nompumelelo Thelma Mobe ◽  
Sebinasi Dzikiti ◽  
Timothy Dube ◽  
Dominic Mazvimavi ◽  
Zanele Ntshidi
Keyword(s):  
Growth Stages ◽  
Arid Environments ◽  
Apple Orchards ◽  
Water Utilization ◽  
Utilization Patterns ◽  
Different Growth Stages ◽  
Semi Arid
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