Dynamics of Perennial Plants in the Mulga (Acacia aneura F. Muell) Zone of Western Australia. I. Rates of Population Change.

1986 ◽  
Vol 8 (1) ◽  
pp. 18 ◽  
Author(s):  
HG Gardiner

The dynamics of populations of six plant species and their responses to environmental factors were examined at Yeelirrie station in the Mulga Zone rangelands of Western Australia. Populations of plants were sampled using sequential maps drawn from low level aerial photographs of areas from which livestock had been removed and which were fenced either to exclude or permit grazing by kangaroos (Macropus rufus Desmarest and Macropus robustus Gould). All six plant species were favoured by the combination of wet years (1973-76) and the removal of livestock from these arid rangelands. Increases ranged from about 20 plants/ha/yr (Eremophila leucophylla, Benth.) to more than 700 plants/ha/yr (Eremophila spectabilis, C.A. Gardn.) during this period. Drought (1977-1979) resulted in significant declines that ranged from about 10 plants/ha/yr (Eremophila leucophylla) to nearly 600 plants/ha/yr (Eremophila spectabilis) while three species (Eremophila leucophylla, Maireana glomerifolia, (F. Muell. et Tate) P.G. Wilson and Ptilotus obovatus, Gaud.) either did not change or increased by only 30 to 60 plants/ha/yr during this period. Responses to kangaroo grazing were strongest during 'normal', post-drought years (1980-82) when Eragrostis xerophila, Domin. decreased by 178 plants/ha/yr on grazed areas while on protected areas there was an increase of 299 plants/ha/yr. This response was due to effects on both recruitment and, as discussed by Gardiner (1986), survival. Maireana glomerifolia, another important plant for livestock was suppressed by kangaroo grazing via reduced recruitment during the 'normal' period. Other species (Frankenia paucifora, DC. and Eremophila spectabilis) responded positively to kangaroo grazing activity during the same period.

1986 ◽  
Vol 8 (1) ◽  
pp. 28 ◽  
Author(s):  
H.G Gardiner

Survival rates of arid-land perennial plant species were significantly related to climate, site factors, and grazing by kangaroos (Macropus rufus, Desmarest and Macropus robustus, Gould). Rainfall patterns ranging from severe drought to well above average resulted in responses in all species. All but Frankenia (Frankeniapauciflora, DC) responded to spatial and temporal site factors. Survival of wire wanderrie grass (Eragrostis xerophila, Domin) was severely reduced by grazing kangaroos, while poverty bush (Eremophila spectabilis, C.A. Gardn.) and Frankenra responded positively to kangaroo activity. Cotton bush (Ptilotus obovatus, Gaud.), ball-leaf bluebush (Marreana glomerifolia), (F. MueH et Tate) Wils. and Wilcox bush (Eremophila leucophylla, Benth.) showed no survival response to kangaroo grazing. The application of maximum likelihood procedures permitted subtle effects to be detected and several significant causal factors to be separated.


2017 ◽  
Vol 28 (1-2) ◽  
pp. 28-35 ◽  
Author(s):  
B. A. Baranovski

Nowadays, bioecological characteristics of species are the basis for flora and vegetation studying on the different levels. Bioecological characteristics of species is required in process of flora studying on the different levels such as biotopes or phytocenoses, floras of particular areas (floras of ecologically homogeneous habitats), and floras of certain territories. Ramensky scale is the one of first detailed ecological scales on plant species ordination in relation to various environmental factors; it developed in 1938 (Ramensky, 1971). A little later (1941), Pogrebnyak’s scale of forest stands was proposed. Ellenberg’s system developed in 1950 (Ellenberg, 1979) and Tsyganov’s system (Tsyganov, 1975) are best known as the systems of ecological scales on vascular plant species; these systems represent of habitat detection by ecotopic ecomorphs of plant species (phytoindication). Basically, the system proposed by Alexander Lyutsianovich Belgard was the one of first system of plant species that identiified ectomorphs in relation to environmental factors. As early as 1950, Belgard developed the tabulated system of ecomorphs using the Latin ecomorphs abbreviation; he also used the terminology proposed in the late 19th century by Dekandol (1956) and Warming (1903), as well as terminology of other authors. The article analyzes the features of Belgard’s system of ecomorphs on vascular plants. It has certain significance and advantages over other systems of ecomorphs. The use of abbreviated Latin names of ecomorphs in tabular form enables the use shortened form of ones. In the working scheme of Belgard’s system of ecomorphs relation of species to environmental factors are represented in the abbreviated Latin alphabetic version (Belgard, 1950). Combined into table, the ecomorphic analysis of plant species within association (ecological certification of species), biotope or area site (water area) gives an explicit pattern on ecological structure of flora within surveyed community, biotope or landscape, and on environmental conditions. Development and application by Belgrard the cenomorphs as «species’ adaptation to phytocenosis as a whole» were completely new in the development of systems of ecomorphs and, in this connection, different coenomorphs were distinguished. Like any concept, the system of ecomorphs by Belgard has the possibility and necessity to be developed and added. Long-time researches and analysis of literature sources allow to propose a new coenomorph in the context of Belgard’s system of ecomorphs development: silvomargoant (species of forest margin, from the Latin words margo – edge, boundary (Dvoretsky, 1976), margo – margin, ad margins silvarum – along the deciduous forest margins). As an example of ecomorphic characterization of species according to the system of ecomorphs by Belgard (when the abbreviated Latin ecomorph names are used in tabular form and the proposed cenomorph is used), it was given the part of the table on vascular plants ecomorphs in the National Nature Park «Orelsky» (Baranovsky et al). The Belgard’s system of ecomorphs is particularly convenient and can be successfully applied to data processing in the ecological analysis of the flora on wide areas with significant species richness, and the proposed ecomorph will be another necessary element in the Belgard’s system of ecomorphs. 


1987 ◽  
Vol 35 (2) ◽  
pp. 135 ◽  
Author(s):  
RB Hacker

Species responses to grazing and environmental factors were studied in an arid halophytic shrubland community in Western Australia. The grazing responses of major shrub species were defined by using reciprocal averaging ordination of botanical data, interpreted in conjunction with a similar ordination of soil chemical properties and measures of soil erosion derived from large-scale aerial photographs. An apparent small-scale interaction between grazing and soil salinity was also defined. Long-term grazing pressure is apparently reduced on localised areas of high salinity. Environmental factors affecting species distribution are complex and appear to include soil salinity, soil cationic balance, geomorphological variation and the influence of cryptogamic crusts on seedling establishment.


1999 ◽  
Vol 123 (3) ◽  
pp. 437-443 ◽  
Author(s):  
T. J. J. INGLIS ◽  
S. C. GARROW ◽  
C. ADAMS ◽  
M. HENDERSON ◽  
M. MAYO ◽  
...  

A cluster of acute melioidosis cases occurred in a remote, coastal community in tropical Western Australia. Molecular typing of Burkholderia pseudomallei isolates from culture-confirmed cases and suspected environmental sources by pulsed-field gel electrophoresis (PFGE) of XbaI chromosomal DNA digests showed that a single PFGE type was responsible for five cases of acute infection in a community of around 300 during a 5 week period. This temporal and geographical clustering of acute melioidosis cases provided a unique opportunity to investigate the environmental factors contributing to this disease. B. pseudomallei isolated from a domestic tap at the home of an asymptomatic seroconverter was indistinguishable by PFGE. Possible contributing environmental factors included an unusually acid communal water supply, unrecordable chlorine levels during the probable exposure period, a nearby earth tremor, and gusting winds during the installation of new water and electricity supplies. The possible role of the potable water supply as a source of B. pseudomallei was investigated further.


2021 ◽  
Vol 45 (1) ◽  
Author(s):  
Minwoo Oh ◽  
Yoonjeong Heo ◽  
Eun Ju Lee ◽  
Hyohyemi Lee

Abstract Background As trade increases, the influx of various alien species and their spread to new regions are prevalent, making them a general problem globally. Anthropogenic activities and climate change have led to alien species becoming distributed beyond their native range. As a result, alien species can be easily found anywhere, with the density of individuals varying across locations. The prevalent distribution of alien species adversely affects invaded ecosystems; thus, strategic management plans must be established to control them effectively. To this end, this study evaluated hotspots and cold-spots in the degree of distribution of invasive alien plant species, and major environmental factors related to hot spots were identified. We analyzed 10,287 distribution points of 126 species of alien plant species collected through a national survey of alien species using the hierarchical model of species communities (HMSC) framework. Results The explanatory and fourfold cross-validation predictive power of the model were 0.91 and 0.75 as area under the curve (AUC) values, respectively. Hotspots of invasive plants were found in the Seoul metropolitan area, Daegu metropolitan city, Chungcheongbuk-do Province, southwest shore, and Jeju Island. Hotspots were generally found where the highest maximum summer temperature, winter precipitation, and road density were observed. In contrast, seasonality in temperature, annual temperature range, precipitation during summer, and distance to rivers and the sea were negatively correlated to hotspots. The model showed that functional traits accounted for 55% of the variance explained by environmental factors. Species with a higher specific leaf area were found where temperature seasonality was low. Taller species were associated with a larger annual temperature range. Heavier seed mass was associated with a maximum summer temperature > 29 °C. Conclusions This study showed that hotspots contained 2.1 times more alien plants on average than cold-spots. Hotspots of invasive plants tended to appear under less stressful climate conditions, such as low fluctuations in temperature and precipitation. In addition, disturbance by anthropogenic factors and water flow positively affected hotspots. These results were consistent with previous reports on the ruderal and competitive strategies of invasive plants, not the stress-tolerant strategy. Our results supported that the functional traits of alien plants are closely related to the ecological strategies of plants by shaping the response of species to various environmental filters. Therefore, to control alien plants effectively, the occurrence of disturbed sites where alien plants can grow in large quantities should be minimized, and the waterfront of rivers must be managed.


2007 ◽  
Vol 2007 ◽  
pp. 233-233 ◽  
Author(s):  
Armin Towhidi ◽  
Farnoush Rostami ◽  
Reza Masoumi

In Iran, Javan (2001) has reported the digestibility some arid rangelands plants by bovine rumen liquor. The determination of in vivo digestibility of wheat straw implies that camel apparently digested poor quality roughages more than cattle and sheep (Cianci et al., 2004). Therefore, It is required to measure the in vitro digestibility of herbages by camel rumen liquor. In province of yazd, nutritive value of 11 different plant species for camel were determined (Towhidi, 2007). The objectives of the current study were to determine 1) the chemical composition, gross energy of the most consuming plant species from rangeland of Semnan province including Seidlitzia rosmarinu, Tamarix tetragyna, Tamarix strica, Halostachys spp, Saudea fruticosa., Alhagi camelorum, Haloxylon ammondendron., Salsola arbescola, Hammada salicornica and, 2) in vitro digestibility of the plants by camel rumen liquor.


2016 ◽  
Vol 42 (1) ◽  
pp. 33-40 ◽  
Author(s):  
Anatoliy A. Khapugin ◽  
Tatyana B. Silaeva ◽  
Anastasia A. Semchuk ◽  
Elena N. Kunaeva

Abstract Population-based studies of endangered plant species are key methods for assessment of the status for these plants at any territory. Plant species of the Orchidaceae family are sensitive components in natural ecosystems. That is why determination of the status for their populations can be considered as indicators for the status of natural ecosystem position as a whole. Investigations of three Orchidaceae species populations (Orchis militaris L., Epipactis palustris (L.) Crantz, Malaxis monophyllos (L.) Swartz) were carried out in Central Russia (Republic of Mordovia). Abundance, density, structure and dynamics of populations of these species were studied. Species composition of accompanying flora was established for each rare species. Some morphometrical parameters of individuals for the studied species were measured. Features of ontogenetic spectrum for Orchis militaris and Epipactis palustris populations were shown.


2017 ◽  
Vol 39 (1) ◽  
pp. 33 ◽  
Author(s):  
Grant D. Linley ◽  
Katherine E. Moseby ◽  
David C. Paton

Burrowing bettongs (Bettongia lesueur) reached high densities within the fenced Arid Recovery reserve. Grazing pressure was assessed by comparing the vegetation inside and outside the reserve during April in 2012, 2013 and 2014. Mean numbers of bettong tracks crossing small 10 m × 1 m plots overnight in the main exclosure were 20 in 2012, decreasing to 4 in 2013 and 3 in 2014. Similar declines were present in the second expansion, where tracks decreased from 7 in 2012 to 3 in 2013 and 2 in 2014. Perennial plant species richness decreased significantly over the study period. Acacia aneura, Acacia ligulata, Atriplex vesicaria, Crotalaria eremaea, Dodonaea viscosa, Enchylaena tomentosa, Maireana astrotricha and Sida ammophila were the most heavily grazed species within the reserve. Overall, more than 25% of plants showed some form of conspicuous grazing. C. eremaea and E. tomentosa showed little damage outside the reserve. Inside the reserve many C. eremaea were dead and heavily browsed and few E. tomentosa remained. Recent recruitment of A. ligulata and D. viscosa was also much higher outside the reserve. High densities of burrowing bettongs were associated with declines in vegetation condition potentially impacting other species and the ecosystem as a whole.


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