Distribution of Grass Species and Attributes of Grasses Near a Bore Drain in a Grazed Semi-arid Subtropical Grassland

1997 ◽  
Vol 45 (5) ◽  
pp. 919 ◽  
Author(s):  
R. W. Rogers ◽  
C. Stride
Keyword(s):  
Introduced Species ◽  
Carbon Assimilation ◽  
Distribution Patterns ◽  
Common Species ◽  
Grass Species ◽  
Semi Arid ◽  
Selection Of

The distribution of grass species and a selection of attributes of those species were related to distance from water in an otherwise natural, sheep-grazed, semi-arid, subtropical grassland at Glencoban Station near Cunnamulla in south-western Queensland, Australia. Twenty common species could be classified as decreaser, increaser or neutral with respect to stocking pressure based on distribution patterns with respect to distance from water. No species known to be introduced to Australia were present. The occurrence of a diversity of vegetative and diaspore attributes and carbon assimilation pathways were also shown to be related to stocking pressure. The attributes studied showed autocorrelation in two groups, which related to the higher level taxonomy of the grasses and to response to stocking. Chloridoid grasses increase and andropogonoid grasses decrease under high stocking pressure. In this grassland, which has no introduced species, a syndrome of stocking-related attributes can be discerned.

Diversity of rhizobia nodulating sulla (Hedysarum coronarium L.) and selection of inoculant strains for semi-arid Tunisia

2011 ◽  
Vol 62 (1) ◽  
pp. 77-84 ◽  
Author(s):  
Sana Dhane Fitouri ◽  
Darine Trabelsi ◽  
Sabrine Saïdi ◽  
Kais Zribi ◽  
Fayçal Ben Jeddi ◽  
...  
Keyword(s):  
Hedysarum Coronarium ◽  
Semi Arid ◽  
Selection Of

The germinable soil seedbank of Eucalyptus victrix grassy woodlands at Roy Hill station, Pilbara district, Western Australia

2004 ◽  
Vol 26 (1) ◽  
pp. 17 ◽  
Author(s):  
R. A. Graham ◽  
S. K. Florentine ◽  
J. E. D. Fox ◽  
T. M. Luong
Keyword(s):  
Species Composition ◽  
Western Australia ◽  
Perennial Grass ◽  
Summer Rainfall ◽  
Distribution Patterns ◽  
Grass Species ◽  
Surface Areas ◽  
Hill Station ◽  
Soil Seedbank ◽  
Germinable Seed

The paper reports soil seedbank species composition, of Eucalyptus victrix grassy woodlands, of the upper Fortescue River in the Pilbara District, Western Australia. In this study, our objectives were to investigate germinable soil seedbanks and species composition in response to three simulated seasons, using emergence. Variation in seed density from three depths was tested. Four field sites were sampled. Thirty samples were collected in late spring, after seed rain and before summer rainfall. From each sample spot, three soil depths (surface, 1–5, and 6–10 cm) were segregated from beneath surface areas of 100 cm2. Samples were later incubated in a glasshouse to simulate three different seasonal conditions (autumn, winter and spring). Germinating seedlings were recorded on emergence and grown until identified. Forty-one species germinated, comprising 11 grasses (7 annuals and 4 perennials), 25 annual herbs and 5 perennial herbs. Distribution patterns of germinable seed in both the important annual grass Eragrostis japonica and the perennial Eragrostis setifolia (a preferred cattle fodder species), suggest that seedbank accumulation differs among species and between sites. In part, this may be associated with the absence of grazing. Species with most total germinable seed were E. japonica (Poaceae; 603/m2), and the annual herbs Calotis multicaulis (Asteraceae; 346/m2), and Mimulus gracilis (Scrophulariaceae; 168/m2). Perennial grass seed was sparse. Spring simulation gave most germination (1059), followed by autumn (892) and winter (376) sets. Greatest species diversity was produced from the spring simulation (33 species), followed by autumn (26), and winter (22). Of the total germination, 92% came from 17 species that were represented in all three simulations. Of the 1227 grass seedlings counted, most were recruited from the surface soil (735), followed by the 5 (310) and 10 (182) cm depths. Marginally more grass seedlings germinated from the spring simulation (558) than the autumn set (523). Only 11.9% of grass germinants came from the winter simulation. All grass species recruited from the soil seedbanks had a C4 photosynthetic pathway. Except for Cenchrus ciliaris all grass species are native to Australia. Of the four sites sampled, one fenced to exclude cattle five years earlier had significantly more germination than the three unfenced sites. Seedbank sampling produced several new records for plants in the areas sampled.

Distribution of moss-inhabiting diatoms along an altitudinal gradient at sub-Antarctic Îles Kerguelen

2007 ◽  
Vol 19 (1) ◽  
pp. 17-24 ◽  
Author(s):  
Niek J.M. Gremmen ◽  
Bart van de Vijver ◽  
Yves Frenot ◽  
Marc Lebouvier
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Altitudinal Gradient ◽  
Cross Validation ◽  
Strong Relationship ◽  
Distribution Patterns ◽  
Common Species ◽  
Important Variable ◽  
Diatom Species ◽  
Expected Species Richness

Altitudinal gradients provide excellent opportunities to study relationships between species distribution and climatic variables. We studied the species composition of 39 samples of moss-inhabiting diatoms, collected at 50 m intervals from 100–650 m above sea level. The samples contained a total of 130 diatom species, of which 51 occurred in 10 or more samples. Altitude appeared to be the most important variable explaining variation in species composition. Of the 51 common species, 33 showed a significant relationship with altitude. Although the majority of the latter declined with increasing altitude, for nine species the probability of occurrence first increased with increasing elevation, but decreased again at higher altitudes, and four species increased systematically with elevation. As a result, expected species richness per sample decreased from an estimated 43 at 100 m to 25 species per sample at 650 m. Diatom distribution patterns proved to be suitable predictors of the altitudinal position of sample sites. Cross-validation yielded a strong relationship between predicted and observed altitudes.

scholarly journals Selection of Lentil (Lens culunaris L.) Lines Grown at Different Sowing Dates for Their Precocity and Their Agronomic Performance under Semi-arid Climate of Tunisia

2021 ◽  
Author(s):  
A. Ouji ◽  
M. Mechri ◽  
S. Wassli ◽  
K. Shiv ◽  
M. Kharrat
Keyword(s):  
Arid Zone ◽  
Sowing Date ◽  
High Yield ◽  
Research Station ◽  
Short Cycle ◽  
Cropping Season ◽  
Sowing Dates ◽  
Significant Yield ◽  
Semi Arid ◽  
Selection Of

Background: In Tunisia, water deficit and heat stress during the end of cycle are more frequent and causes significant yield losses. Selection of short cycle lines could be a good solution to escape the effect of heat and drought during the end of cycle. Furthermore, there is little published information on the effect of the sowing date on yield and its components in lentils. The aim of this study was to investigate the effect of the sowing date on yield and its components of some lentil lines. The best productive and early lines will be selected and therefore proposed for registration in the official catalog of plant varieties. The availability of these varieties to farmers could increase lentil production. Methods: Sixteen genotypes of lentil out of which 14 were advanced lines and 2 were checks varieties were used in this study. The field experiment was conducted during the 2017-2018 cropping season at Kef research station located in a semi-arid zone in north western Tunisia. Genotypes were sown on December 15th, 2017 and February, 7th, 2018. Seventeen agro-morphological parameters were recorded. Result: Based on agro-morphological analysis, lentil lines exhibited considerable genetic variability. Among the tested lines, L3 line seem to be the earliest lines. It showed high yield as well in timely and late sown dates. This line deserves more attention to develop short-cycle and high yielding variety.

Selection of Dry Pea (Pisum Sativum) Varieties and their Performance by Comparison with Barley and Wheat in Mediterranean Environments

1994 ◽  
Vol 30 (4) ◽  
pp. 477-481
Author(s):  
A. Hadjicristodoulou
Keyword(s):  
Pisum Sativum ◽  
Durum Wheat ◽  
Protein Content ◽  
Arid Areas ◽  
Wheat Varieties ◽  
Mediterranean Countries ◽  
Supplementary Irrigation ◽  
Rainfed Conditions ◽  
Semi Arid ◽  
Selection Of

SUMMARYThe possibility of growing dry peas in the semi-arid areas of Mediterranean countries was assessed by comparing dry pea (Pisum sativum L.) varieties with the highest yielding barley and durum wheat varieties under rainfed conditions and with supplementary irrigation in Cyprus. The yield of barley cv. Kantara was greater than that of the best pea variety selected, PS 210713, especially under the driest conditions, but the differences between cereals and dry pea varieties were smaller when grown in areas where there was more rain or where supplementary irrigation was supplied. The protein content of the dry seeds and straw of the peas was higher than those of the cereals. It is concluded that selected varieties of dry peas could be grown in dry Mediterranean areas, particularly in rotation with barley or wheat.Pisum sativum L. para zonas mediterráneas

Habitat filtering of six coexisting Heliconia species in a lowland tropical rain forest in Amazonian Ecuador

2019 ◽  
Vol 35 (2) ◽  
pp. 91-94 ◽  
Author(s):  
Elizabeth L. Tokarz ◽  
Pablo Álvia ◽  
Renato Valencia ◽  
Simon A. Queenborough
Keyword(s):  
Rain Forest ◽  
National Park ◽  
Distribution Patterns ◽  
Common Species ◽  
Habitat Filtering ◽  
Yasuni National Park ◽  
Amazonian Ecuador ◽  
Amazonian Rain Forest ◽  
Random Manner ◽  
Occurrence Pattern

AbstractHerbaceous plants are often under-studied in tropical forests, despite their high density and diversity, and little is known about the factors that influence their distribution at microscales. In a 25-ha plot in lowland Amazonian rain forest in Yasuní National Park, Ecuador, we censused six species of Heliconia (Heliconiaceae) in a stratified random manner across three topographic habitat types. We observed distribution patterns consistent with habitat filtering. Overall, more individuals occurred in the valley (N = 979) and slope (N = 847) compared with the ridge (N = 571) habitat. At the species level, Heliconia stricta (N = 1135), H. spathocircinata (N = 309) and H. ortotricha (N = 36) all had higher abundance in the valley and slope than ridge. Further, H. vellerigera (N = 20) was completely absent from the ridge. Conversely, H. velutina (N = 903) was most common in the drier ridge habitat. The two most common species (H. stricta and H. velutina) had a reciprocal or negative co-occurrence pattern and occurred preferentially in valley versus ridge habitats. These results suggest that taxa within this family have different adaptations to the wetter valley versus the drier ridge and that habitat partitioning contributes to coexistence.

scholarly journals Effects of polymer cyclohexane application on lentil pod shatter in semi-arid region of Turkey

2018 ◽  
Vol 64 (No. 3) ◽  
pp. 136-142 ◽  
Author(s):  
Aslan Hasan ◽  
Gayberi Mahmut ◽  
Kahraman Abdullah
Keyword(s):  
Arid Region ◽  
High Yield ◽  
Semiarid Region ◽  
Application Time ◽  
Crucial Feature ◽  
Pod Shatter ◽  
Semi Arid Region ◽  
Semi Arid ◽  
Selection Of ◽  
Plot Experiment

Pod shattering in lentil which is vital plant of dry lands is a crucial feature for high yield. Selection of lentil variety is very important in order to reduce pod shatter. Some of lentil varieties are very productive; however, shattering loss decreases profitable yields. In this study, reduction of pod shatter in lentil varieties was investigated with application of polymer cyclohexane compounds. An experiment was conducted with split-split-plot experiment design with two lentil varieties (‘Firat-87’ and ‘Cagil’), two application time (podset and 15 days before harvest (DBH)) and three application doses (0, 0.5, 2 l·ha<sup>–1</sup>) as triplicate during two years. Effects of application time on podset were found statistically insignificant and application of 0.5 l·ha<sup>–1</sup> dose was found effective for 15 DBH application time. As a result, 0.5 pod shatter polymer cyclohexane and 15 DBH was found as optimum doses and application time, respectively in order to reduce pod shatter loss by nearly 1% for semiarid region of Turkey.

scholarly journals Biotic element analysis of reptiles of China: A test of vicariance model

2013 ◽  
Vol 59 (4) ◽  
pp. 449-457 ◽  
Author(s):  
Youhua Chen
Keyword(s):  
East Asia ◽  
Current Distribution ◽  
Related Species ◽  
Distribution Patterns ◽  
Biodiversity Hotspots ◽  
Element Analysis ◽  
Closely Related Species ◽  
Areas Of Endemism ◽  
Guizhou Plateau ◽  
Selection Of

Abstract In this contribution, I identify possible biotic elements of reptiles of China using biotic element analysis. I test whether the vicariance model could significantly shape reptilian current distribution patterns. My results show that dispersal is prevailing for reptiles in China. There are four major biotic elements in reptilian distribution, which are East Xizang, Yunnan-Guizhou Plateau, Taiwan and Hainan, respectively. The test of distributional areas is significantly more clustered than expected by chance, while in another test that closely related species are homogeneously distributed across biotic elements cannot be rejected. Therefore I argued that vicariance might be one of the key processes in patterning reptilian distribution in China. In addition, I develop an improved biotic element analysis in biogeographic studies, by performing biotic element analysis in an iterative manner in order to diagnose more geographically restricted elements until no noise components found. The importance of antecedent selection of distributional data for the subsequent analysis is also discussed. Besides, my study indicates that biodiversity hotspots are not fully overlapped with areas of endemism for reptilians in East Asia.

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