Water relations and mineral nutrition of Triodia grasses on desert dunes and interdunes

2008 ◽  
Vol 56 (5) ◽  
pp. 408 ◽  
Author(s):  
Alasdair M. Grigg ◽  
Erik J. Veneklaas ◽  
Hans Lambers
Keyword(s):  
Plant Species ◽  
Soil Depth ◽  
Water Status ◽  
Sand Dunes ◽  
Temporal Distribution ◽  
Nutrient Concentrations ◽  
Wet Season ◽  
Water Storage Capacity ◽  
Foliar Nutrient ◽  
Desert Dunes

Desert dunes and interdunes provide habitat heterogeneity and profoundly influence the spatial and temporal distribution of water and nutrients throughout the landscape. These underlying physical processes shape the plant species composition and their ecophysiology. Spinifex grasses dominate the vegetation throughout much of Australia and are categorised into two groups; ‘soft’ species occur mostly in northern, subtropical to semiarid regions, whereas ‘hard’ species occur mostly throughout the dry centre and southern interior. This study examined the water and nutrient relations and leaf anatomy of dominant ‘soft’ and ‘hard’ spinifex in the Great Sandy Desert, where their distributions overlap. The ‘soft’ species, Triodia schinzii (Henrard) Lazarides, occurs only on sand dunes, whereas the ‘hard’ species, T. basedowii E.Pritz., is restricted to the flat interdunes. We proposed two hypotheses: 1) that the dune species, T. schinzii would display more favourable water status and 2) the interdune species, T. basedowii would display higher leaf nutrient concentrations. Triodia schinzii displayed significantly less negative leaf water potentials at predawn and at midday (–0.4 and –2.0 MPa, respectively) than T. basedowii (–0.9 and –3.0 MPa, respectively) throughout the middle of the dry season. Photosynthesis rates were also significantly higher in T. schinzii than T. basedowii in the wet season (140 v. 84 nmol g–1 s–1), but there were no significant differences between species in leaf conductance. Leaf δ13C composition confirmed anatomical observations that both species were C4 and supported the finding that T. schinzii displayed significantly greater photosynthetic water-use efficiency during the wet season than T. basedowii. In general, foliar nutrient concentrations were not significantly different between species; however, both species exhibited especially low leaf P and to a lesser extent N. We conclude that water is more readily available in the dune than the interdune as a result of greater soil depth and associated water storage capacity. These properties are considered the main factors influencing plant species distribution. Given the climatic and geographic distribution of these two Triodia species, it is suggested that sand dunes provide a mesic corridor for T. schinzii to extend its range from higher rainfall areas into the arid interior.

Nutrient response to soil and litter metabolic activity in a transect across a seasonal wetland

2003 ◽  
Vol 54 (3) ◽  
pp. 243 ◽  
Author(s):  
S. Qiu ◽  
A. J. McComb ◽  
R. W. Bell ◽  
J. A. Davis
Keyword(s):  
Microbial Biomass ◽  
Microbial Activity ◽  
Nutrient Dynamics ◽  
Sand Dunes ◽  
Co2 Production ◽  
Nutrient Concentrations ◽  
Co2 Efflux ◽  
Wet Season ◽  
Surface Soils ◽  
Substrate Induced Respiration

Many wetlands in the interdunal depression of coastal sand dunes of the Swan Coastal Plain are surrounded by partially vegetated catchments. Although litter can be an important source of nutrients, little is known about litter related microbial activity in these catchments, especially its role in regulating nutrient concentrations in soils during the wet season. Heterotrophic microbial activity and phosphorus (P) dynamics were monitored before and after the onset of the wet season along transects from a vegetated catchment to the lakebed in Thomsons Lake, south-western Australia. Microbial activity was measured in the field as CO2 efflux (range from 47 to 176 mg CO2 m–2 h–1) and in the laboratory as substrate-induced-respiration (SIR; range from 11 to 133 μg g–1 h–1). Substrate-induced-respiration was positively correlated with soil organic content, and was concentrated in surface soils. In contrast, in the exposed lakebed most microbial biomass was below the surface, in the 10–30 cm depth zone. There were significant changes in nutrient dynamics in response to soil microbial activity. Before rain, P extracted by anion exchange membrane (PAEM) was well correlated with site litter and plant debris (r2 = 0.90, P�<�0.001), suggesting that PAEM in soils was litter-sourced. This relationship was modified during the wet season: there was an overall increase in microbial biomass P (PMB; from average 7.5 μg g–1 to 21.6 μg g–1), and a decrease in PAEM : PMB in surface soils. Along the study transect, the assimilation index PAEM : PMB declined towards the wetland, where soils were more silty and organic, and CO2 production was significantly higher. Our data suggest that heterotrophic microbial activity has a significant role in regulating P flux from catchment litter during the wet season, which would affect the mobility of litter-sourced P from catchment to the wetland.

scholarly journals Seasonal changes in water quality and macrophytes and the impact of cattle on tropical floodplain waterholes

2012 ◽  
Vol 63 (9) ◽  
pp. 788 ◽  
Author(s):  
N. E. Pettit ◽  
T. D. Jardine ◽  
S. K. Hamilton ◽  
V. Sinnamon ◽  
D. Valdez ◽  
...  
Keyword(s):  
Water Quality ◽  
Seasonal Changes ◽  
Aquatic Macrophyte ◽  
Plant Cover ◽  
Critical Role ◽  
Dry Season ◽  
Nutrient Concentrations ◽  
Wet Season ◽  
Dry Tropics ◽  
The Impact

The present study indicates the critical role of hydrologic connectivity in floodplain waterholes in the wet–dry tropics of northern Australia. These waterbodies provide dry-season refugia for plants and animals, are a hotspot of productivity, and are a critical part in the subsistence economy of many remote Aboriginal communities. We examined seasonal changes in water quality and aquatic plant cover of floodplain waterholes, and related changes to variation of waterhole depth and visitation by livestock. The waterholes showed declining water quality through the dry season, which was exacerbated by more frequent cattle usage as conditions became progressively drier, which also increased turbidity and nutrient concentrations. Aquatic macrophyte biomass was highest in the early dry season, and declined as the dry season progressed. Remaining macrophytes were flushed out by the first wet-season flows, although they quickly re-establish later during the wet season. Waterholes of greater depth were more resistant to the effects of cattle disturbance, and seasonal flushing of the waterholes with wet-season flooding homogenised the water quality and increased plant cover of previously disparate waterholes. Therefore, maintaining high levels of connectivity between the river and its floodplain is vital for the persistence of these waterholes.

Barcoding of Some Plant Species Using rbcL Gene ‎in the Mediterranean Oolitic Sand Dunes West of Alexandria, Egypt

2021 ◽  
Vol 0 (0) ◽  
pp. 0-0
Author(s):  
Ahmed S. Fouad ◽  
Azza B. Hamed ◽  
Wafaa M. Amer ◽  
Rehab M. Hafez
Keyword(s):  
Plant Species ◽  
Sand Dunes ◽  
Rbcl Gene ◽  
The Mediterranean

scholarly journals Branch elongation and diameter growth were temporally dissociatedin "cerrado" tree species

Hoehnea ◽  
2009 ◽  
Vol 36 (3) ◽  
pp. 437-444 ◽  
Author(s):  
Davi Rodrigo Rossatto
Keyword(s):  
Water Status ◽  
Carbon Assimilation ◽  
Dry Season ◽  
Diameter Growth ◽  
Wet Season ◽  
Dry Period ◽  
Central Brazil ◽  
Branch Growth ◽  
Tree Community ◽  
One Year

Here is a communicating about time differences between branch and diameter growth in a tree community of ten species in Neotropical savanna ("cerrado") of Central Brazil. This work was conducted to study branch expansion and diameter growth in a period of one year between 2006 and 2007. Branch growth had begin in middle dry season and had the peak occurrence during the dry period in September, while diameter growth had begin in late dry season and peaked in the middle of wet season in December. The majority of species followed the same pattern. Branch growth did not have relation with rainfall, while diameter growth had a clear and positive relation with rainfall records. These results suggested that branch growth was not depend on rainfall but only on water status recover, while diameter growth probably depends strongly on water and to carbon assimilation that occurs after branch and leaf expansion.

Pans in humus podzols (Humods and Aquods) in coastal southern Queensland

Soil Research ◽  
1996 ◽  
Vol 34 (1) ◽  
pp. 161 ◽  
Author(s):  
CH Thompson ◽  
EM Bridges ◽  
DA Jenkins
Keyword(s):  
Soil Depth ◽  
Sand Dunes ◽  
Coastal Dunes ◽  
Particle Packing ◽  
Sand Mining ◽  
Coastal Sand Dunes ◽  
Organic Complex ◽  
Coastal Sand ◽  
Coastal Lowlands

An exploratory examination has been made of three different kinds of hardpans found in humus podzols (Humods and Aquods) of the coastal lowlands of southern Queensland, by means of slaking tests, a reactive aluminium test, acid oxalate and pyrophosphate extractions and electron microscopy. Samples from three indurated layers exposed by erosion or sand-mining in large coastal dunes were included for comparison. The investigation confirmed that, a pan in a bleached A2 (albic E) horizon is most likely caused by particle packing and that a pan in a black B2h (spodic) horizon is cemented by an aluminium-organic complex. Yellow-brown pans underlying black organic pans (spodic horizons) were found to be cemented by both a proto-imogolite/allophane complex and an organic substance. An inorganic reactive Al complex differing from the proto-imogolite allophane recorded in the overlying giant podzols appeared to be main cement of three indurated layers in the nearby coastal sand dunes. Mechanical disturbance of the pans, e.g. ripping, is unlikely to improve drainage and effective soil depth in the long term, because the disturbed zones are expected to be re-sealed by packed particles or by the aluminium-organic complex cement.

Frost hardiness and winter photosynthesis of Thujapiicata and Pseudotsugamenzlesll seedlings grown at three rates of nitrogen and phosphorus supply

1995 ◽  
Vol 25 (1) ◽  
pp. 18-28 ◽  
Author(s):  
B.J. Hawkins ◽  
M. Davradou ◽  
D. Pier ◽  
R. Shortt
Keyword(s):  
Net Photosynthesis ◽  
Douglas Fir ◽  
Frost Hardiness ◽  
Nutrient Concentrations ◽  
Nitrogen And Phosphorus ◽  
Red Cedar ◽  
Air Temperatures ◽  
Foliar Nutrient ◽  
One Year ◽  
P Supply

One-year-old seedlings of western red cedar (Thujapiicata Donn ex D.Don) and Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) were grown for one season in five nutrient treatments with nitrogen (N) supplied in solution at rates of 20, 100, or 250 mg•L−1 and phosphorus (P) supplied at rates of 4, 20, or 60 mg•L−1. Growth, onset of dormancy, frost hardiness on six dates, and foliar nutrient concentrations in autumn and spring were measured. Midwinter rates of net photosynthesis and transpiration were measured at air temperatures of 4, 7, and 11 °C in seedlings from all nutrient treatments. Recovery of net photosynthesis and transpiration in whole seedlings from the three N treatments was assessed at intervals for 28 days after the seedlings were frozen to −5, −15, and −25°C. Foliar N content differed significantly among nutrient treatments and was positively correlated with supply. Mitotic activity ceased earliest in plants with low N supply. Douglas-fir seedlings in the low-N treatment also ceased height growth earliest. These differences in growth had no significant correlation with frost hardiness. No consistent differences in frost hardiness among nutrient treatments were observed. Higher rates of N and P supply resulted in higher rates of winter net photosynthesis. Net photosynthesis was reduced dramatically by night frost, with greater damage occurring at lower temperatures. Net photosynthesis recovery occurred most quickly in seedlings with the midrate of N and P supply.

scholarly journals Functional Ecology of Iceplant Taxa and Their Role in Eco-restoration of New Zealand Sand Dunes

2021 ◽  
Author(s):  
◽  
Guyo Duba Gufu
Keyword(s):  
New Zealand ◽  
Plant Species ◽  
Plant Communities ◽  
Growth Rates ◽  
Sand Dunes ◽  
Intergeneric Hybrid ◽  
Leaf Production ◽  
Natural Plant ◽  
Carpobrotus Edulis

<p>Biological invasion by non-native plant species has often been cited as a cause of native biodiversity loss. While the outcome of species invasions depends on interactions between exotic and resident native species, most studies of biological invasions have focused solely on the direct negative impacts of non-indigenous species on native biota. Although investigations of the role of competition in shaping natural plant communities were dominant in the previous generations and are still popular, more recent experimental research has uncovered the striking influence of facilitation on community dynamics. This thesis aims to investigate competitive and facilitative influence of the invasive South African iceplant (Carpobrotus edulis) on Spinifex sericeus, a native foredune grass species, with particular reference to implications of these interactions for dune restoration in New Zealand. It further explores the growth rates, substrate preferences and mating systems of the exotic and native iceplant taxa found in New Zealand. I begin by briefly outlining the influence of competition and facilitation on natural plant communities with reference to the role of facilitation in eco-restoration. I also give a few examples where exotic species have been found to facilitate native ones. Secondly, a neighbour removal experiment was conducted on coastal sand dunes with the main aim of studying the effects of Carpobrotus edulis on establishment of Spinifex sericeus at the foredune region. Finally, I compared the growth rates of the most widely distributed iceplant taxa in New Zealand in different substrates and the breeding systems of the exotic Carpobrotus.  Examples abound in literature of exotic plant species facilitating native ones especially in forestry. In the neighbour removal study, Carpobrotus edulis protected Spinifex seedlings against storm erosion, sandblasting and salt sprays while at the same time suppressing its leaf production. Suppression of Spinifex leaf production was more pronounced at top of the dune where stress elements is presumably more benign. There was no evidence of allelopathic suppression of Spinifex by C. edulis. Only Carpobrotus chilensis displayed some level of substrate preference by putting on relatively lower biomass in gravel. The exotic Carpobrotus spp. put on greater dry matter content than the native Disphyma australe and the Carpobrotus-x-Disphyma hybrid. The hybrid displayed a faster vegetative growth rate whereas D. australe allocated relatively more biomass to the roots than the shoot. Both Carpobrotus spp. are self compatible and highly capable of intrageneric and intergeneric hybridisation. Mass removal of the existing exotic iceplant stands from foredunes along high energy coasts is not advisable as they serve as useful stabilisers. The intergeneric hybrid is sexually sterile with sparsely spread stolons that could allow co-occurrence with other species and therefore is more suitable for foredune stabilisation. However, more research needs to be conducted on the ecology of the intergeneric hybrid.</p>

Characteristics of Arboreal Marsupial Habitat in the Semi-Arid Woodlands of Northern Queensland.

1996 ◽  
Vol 23 (2) ◽  
pp. 185 ◽  
Author(s):  
SA Munks ◽  
R Corkrey ◽  
WJ Foley
Keyword(s):  
Water Concentration ◽  
Basal Area ◽  
Faecal Pellet ◽  
Nutrient Concentrations ◽  
Brushtail Possum ◽  
Phascolarctos Cinereus ◽  
Foliar Nutrient ◽  
Foliar Nutrient Concentrations ◽  
Arboreal Habitat ◽  
Semi Arid

The distribution of the koala (Phascolarctos cinereus) and the common brushtail possum (Trichosurus vulpecula) within the Prairie-Torrens Creek Alluvials province of the Desert Upland region of north-western Queensland was examined. The optimum habitat for each species as indicated by the occurrence of faecal pellet groups was found to be that associated with creek-lines. However, other land types were also used by each species to varying degrees. The relationship between various habitat variables and pellet group counts was investigated using Multiple regression and a Generalised linear model. Proximity to creek-bed, total basal area of trees, species richness and Acacia basal area (negative) best explained the occurrence of koalas. Proximity to creek-bed, Acacia basal area (negative), total basal area of trees, and available water (negative) best explained the occurrence of brushtail possums. In contrast to studies of arboreal species in the moist-south-eastern forests of Australia no relationship was found between foliar nutrient concentrations and the occurrence of koalas or brushtail possums. However, a significant relationship was found between leaf water concentration and the occurrence of koalas. It is suggested that water availability is the paramount factor defining preferred arboreal habitat in arid and semi-arid woodlands.

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