Population differentiation of the Stellaria longipes complex within Saskatchewan's Athabasca sand dunes

1987 ◽  
Vol 65 (8) ◽  
pp. 1726-1732 ◽  
Author(s):  
S. Ellen Macdonald ◽  
C. C. Chinnappa ◽  
David M. Reid ◽  
Brett G. Purdy
Keyword(s):  
Selection Pressure ◽  
Sand Dune ◽  
Reproductive Output ◽  
Sand Dunes ◽  
Common Garden ◽  
Fine Sand ◽  
Morphological Characters ◽  
Genetic Isolation ◽  
Dune Field ◽  
Reciprocal Transplants

Stellaria arenicola, a recent derivative within the S. longipes complex, is an endemic of the Athabasca sand dunes. Analysis of 11 morphological characters on 40 genets showed that both the endemic and parental (S. longipes) species are present within the Thomson Bay dune field and that the two forms are distinct. Individuals of S. arenicola were distinguished by only a few characters, typically, large yellow capsules with reflexed teeth and yellowish leaf and stem pigmentation. The endemic also exhibited a higher sexual reproductive output. Many characteristics of vegetative morphology showed plasticity in both species, but the two remained distinct when grown in a common garden. On the sand dunes S. longipes is restricted to beach dunes bordering Lake Athabasca while S. arenicola is predominant on the active dune field inland. The two dune systems represented environmentally distinct microhabitats. The active inner dunes were characterized by an unstable, fine sand substrate and intense insolation. Field reciprocal transplants showed S. longipes was selected against in the inner dune habitat, while S. arenicola performed relatively well on the beach. Stellaria arenicola possibly arose in the active sand dune habitat as a result of selection pressure and genetic isolation.

scholarly journals Geomorphological characteristics of the sand-dune field of the central Kyparissiakos Gulf

2007 ◽  
Vol 40 (4) ◽  
pp. 1530 ◽  
Author(s):  
Th. Karamousalis ◽  
S. Poulos ◽  
H. Maroukian ◽  
G. Ghionis
Keyword(s):  
Sand Dune ◽  
Sand Dunes ◽  
Fine Sand ◽  
Middle Part ◽  
Alluvial Fan ◽  
Last Glacial Period ◽  
Dune Field ◽  
Natural Processes ◽  
Dune Ridge ◽  
The Last Glacial

Sand dunes are sensitive coastal landforms closely related to the evolution (and/or stability) of the beach zone. The present work refers to the central part of the dune field that lies along the middle part of the shoreline of the Kyparissiakos Gulf. The scope of the present investigation is to reveal the geomorphological and sedimentological characteristics of the sand dune field in association with the natural processes contributing to their formation. On the basis of our findings, the dune field of the central Kyparissiakos Gulf consists of four dune ridges, with heights >4.0 m. Their extent indicates the availability of large quantities of sand and the existence of a rather stable wind field. They consist of well sorted medium to fine sand. The alluvial fan of the Zachareiko torrential river has covered the dune field in the area of its mouth and buried the oldest 4th dune ridge to its south. The development of the dune field is estimated to have taken place during the last 3-4 thousand years subsequently to the completion of the rapid sea level rise at the end of the last glacial period.

scholarly journals The Sources of Moisture in the Sand Dunes – The Example of the Western Sahara Dune Field

2014 ◽  
Vol 33 (3) ◽  
pp. 199-204 ◽  
Author(s):  
Elwira Żmudzka ◽  
Dariusz Woronko ◽  
Maciej Dłużewski
Keyword(s):  
Surface Layer ◽  
Moisture Content ◽  
Wind Velocity ◽  
Sand Dune ◽  
Sand Dunes ◽  
Shear Velocity ◽  
Meteorological Conditions ◽  
Aeolian Transport ◽  
Western Sahara ◽  
Dune Field

Abstract Climatic and meteorological conditions may limit the aeolian transport within barchans. An explanation of that issue was the main goal of the investigation held in Western Sahara dune fields located around Tarfaya and Laâyoune. Particular attention was paid to the factors causing the moisture content rising of the sand dune surface layer, which could influence the wind threshold shear velocity in the aeolian transport. The wetted surface layer of sand, when receiving moisture from precipitation or suspensions, reduces the aeolian transport, even in case of wind velocity above 4-5 m s-1. Fog and dew condensation does not affect the moisture of deeper sand layers, what occurs after rainfall.

Seedling desiccation tolerance of Leymus racemosus (Poaceae) (wild rye), a perennial sand-dune grass inhabiting the Junggar Basin of Xinjiang, China

2004 ◽  
Vol 14 (2) ◽  
pp. 233-239 ◽  
Author(s):  
Zhenying Huang ◽  
Yitzchak Gutterman
Keyword(s):  
Desiccation Tolerance ◽  
Sand Dune ◽  
Sand Dunes ◽  
Perennial Grass ◽  
Junggar Basin ◽  
Seedling Development ◽  
Ecological Implications ◽  
Leymus Racemosus ◽  
Seedling Desiccation Tolerance ◽  
Dune Grass

Leymus Racemosus, The Mammoth Wild Rye, Is A Rhizomatous Perennial Grass, Mainly Distributed In The Moving Or Semi-Stabilized Sand Dunes In Deserts Of The Junggar Basin In Xinjiang, China. The Revival Ability Of The Young Seedling After Periods Of Desiccation Can Be Influenced By Several Factors: (1) The Stage Of Seedling Development – The Later The Stage At Dehydration, The Longer The Root Length And The Lower Is The Percentage Of Seedlings That Survive; (2) The Length Of The Period Of Desiccation – The Longer The Period That The Seedlings Are Under Desiccation, The Lower Is The Percentage Of Seedlings That Survive; (3) Endosperm Size – The Smaller The Proportion Of Endosperm That Remains In The Caryopses, The Lower Is The Percentage Of Seedlings That Revive, Determined By (A) The Stage Of Seedling Development, And (B) The Proportion Of The Endosperm That Is Removed By Cutting; And (4) Caryopsis Size – The Larger The Polymorphic Caryopses, The Higher Is The Percentage Of Young Seedlings That Revive From Periods Of Desiccation. The Physiological And Ecological Implications Of L. Racemosus Seedling Desiccation Tolerance Are That Under Extreme Desert And Unpredictable Environmental Conditions, The Chances Of Seedling Establishment Are Increased.

The role of waterlogging and sand accretion in modulating the morphology of the dune slack plant Scirpus americanus

1990 ◽  
Vol 68 (8) ◽  
pp. 1780-1787 ◽  
Author(s):  
Denise M. Seliskar
Keyword(s):  
Sand Dune ◽  
Plant Morphology ◽  
Common Garden ◽  
Stem Growth ◽  
Reciprocal Transplant ◽  
Dune Slack ◽  
Coastal Sand Dune ◽  
Scirpus Americanus ◽  
Common Garden Experiments

Scirpus americanus Pers., a major dune slack plant in coastal sand dune ecosystems, differs in height along transects ranging between the lowest and highest elevational areas of slacks located along the coast of Delaware, U.S.A. Using reciprocal transplant and common garden experiments, results suggest that environmental factors rather than hereditary traits are more important in accounting for the differences in plant morphology expressed in the field. Dune slack plants are exposed to stresses of waterlogging and sand accretion in their natural environment. In controlled greenhouse experiments waterlogging was shown to inhibit stem growth and cause an increase in aerenchymatous tissue, whereas periodic sand deposition caused an increase in the plant height of Scirpus.

scholarly journals Spatial variation of plant species richness in a sand dune field of northeastern Inner Mongolia, China

2016 ◽  
Vol 8 (3) ◽  
pp. 434-442
Author(s):  
Jing Wu ◽  
Jianqiang Qian ◽  
Xianzhang Hou ◽  
Carlos A. Busso ◽  
Zhimin Liu ◽  
...  
Keyword(s):  
Species Richness ◽  
Spatial Variation ◽  
Plant Species ◽  
Inner Mongolia ◽  
Sand Dune ◽  
Plant Species Richness ◽  
Dune Field

Allelopathic potential of Artemisia campestris ssp. caudata on Lake Huron sand dunes

1997 ◽  
Vol 75 (11) ◽  
pp. 1903-1912 ◽  
Author(s):  
Kyeong W. Yun ◽  
M. A. Maun
Keyword(s):  
Seed Germination ◽  
Seedling Growth ◽  
Mycorrhizal Fungi ◽  
Sand Dune ◽  
Sand Dunes ◽  
Dry Weight ◽  
Fungal Colonization ◽  
Test Species ◽  
Allelopathic Potential ◽  
Artemisia Campestris

Greenhouse studies were conducted to test allelopathic effects of Artemisia campestris ssp. caudata on seed germination and seedling growth of several sand-dune species and colonization by mycorrhizal fungi. The aqueous extracts of A. campestris showed no inhibitory effect on seed germination, seedling elongation, or dry-weight growth of plants at lower concentrations (10 and 50%), but 100% concentration of the extracts caused varying degrees of inhibition depending on the test species. The mixing of dry leaves of seedlings of A. campestris to the sand showed severe inhibition of Elymus canadensis seedlings. The percent germination of test species in soil from the rhizosphere of A. campestris was significantly lower than that of the control. The leaf area and dry weight were also lower but the differences were not significant. The aqueous extract inhibited mycorrhizal fungal colonization in roots of three sand-dune grasses. Key words: allelopathy, Artemisia campestris ssp. caudata, seed germination, seedling growth, mycorrhizal fungi.

scholarly journals Modelling and  assessing driving factors of the spatial and temporal dynamics of the sand  dunes in the district of Errachidia, Morocco

2021 ◽  
Author(s):  
Tudal SINSIN ◽  
Fouad MOUNIR ◽  
Ahmed El ABOUDI
Keyword(s):  
Sand Dune ◽  
Temporal Dynamics ◽  
Moving Average ◽  
Sand Dunes ◽  
Ecological Factors ◽  
Temperature And Precipitation ◽  
Spatial And Temporal Dynamics ◽  
Combined Action ◽  
Landsat Satellite ◽  
Dune Dynamics

The desertification affects more than 250,000 ha in the district of Errachidia and results in the expansion of desert landscapes such as the Regs, Hamadas and the Dunes. The latter is a big concern in the district since it is the source of siltation, which threatens dwellings, cultivated lands and water bodies. It is of paramount importance to understand the causes and consequences of silting to develop strategies to combat it. Thus, first, we analysed the spatial and temporal dynamics of sand dunes until 2069 by applying the Seasonal Autoregressive Integrated Moving-Average (SARIMA) model on a time series of sand dune areas. These areas were calculated annually from 1987 to 2019 by computing the sand cover index (SCI) on Landsat satellite images. Furthermore, we evaluated the influence of different natural and human factors such as temperature, precipitation, wind, vegetation, and population growth, on sand dune dynamics using Spearman’s correlation test. The results indicated that the area of sand dunes will increase by 1.7% per year between 2019 and 2069 in the district of Errachidia. This increase would be mainly caused by the combined action of ecological factors, which vary from year to year. In general, temperature and precipitation act indirectly on wind and vegetation to influence the dynamics of sand dunes in hyper-arid areas where the soil is bare or poorly covered with vegetation, where precipitation is low and where temperature is high.

Ecological aspects influencing the helminth community of the wood mouse Apodemus sylvaticus in Dunas de Mira, Portugal

2006 ◽  
Vol 51 (4) ◽  
Author(s):  
Catarina Eira ◽  
Jordi Torres ◽  
José Vingada ◽  
Jordi Miquel
Keyword(s):  
Species Richness ◽  
Sand Dune ◽  
Sand Dunes ◽  
Wood Mouse ◽  
Apodemus Sylvaticus ◽  
Habitat Characteristics ◽  
Helminth Community ◽  
Heligmosomoides Polygyrus ◽  
Ecological Aspects ◽  
Host Sex

AbstractThis paper presents the first extensive data on the helminth community of the wood mouse Apodemus sylvaticus in a coastal sand dune area in Portugal. The 557 hosts analysed in this study were trapped seasonally between autumn 2002 and summer 2005 across 6 habitat types. Twelve helminth species were detected among which, Taenia parva larvae, Angiostrongylus dujardini, Heligmosomoides polygyrus, Syphacia stroma and S. frederici constitute the component species, accounting for 98.7% of all worms. H. polygyrus was the most prevalent helminth parasite. Species richness varied according to habitat and season. The highest species richness was found in sand dunes during winter whereas the lowest was detected along lake margins also during the winter. Some differences in prevalence and mean intensity values were found in relation to year (T. parva larvae and H. polygyrus), habitat (A. dujardini), season (T. parva larvae, H. polygyrus, A. dujardini and S. stroma) and host sex (T. parva larvae and S. stroma). These differences are discussed both in view of the host’s biology and habitat characteristics.

scholarly journals Integrated Geological, Hydrogeological, and Geophysical Investigations of a Barchan Sand Dune in the Eastern Region of Saudi Arabia

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 682
Author(s):  
Mohammed Benaafi ◽  
Sherif M. Hanafy ◽  
Abdullatif Al-Shuhail ◽  
Ammar El-Husseiny ◽  
Jack Dvorkin
Keyword(s):  
Grain Size ◽  
Saudi Arabia ◽  
Water Content ◽  
Sand Dune ◽  
Sand Dunes ◽  
Homogeneous Medium ◽  
Eastern Region ◽  
Large Area ◽  
Electrical Resistivity Survey ◽  
Dune Crest

In arid countries such as Saudi Arabia, aeolian sand often covers a large area of the country. Understanding the variations of sand properties in dunes, including grain size, sorting, mineral composition and water content, can be important for groundwater recharge, environmental, and construction applications. Earlier studies examined properties of sand dunes by collecting samples from the surface. This study aims to investigate variations of sand properties within a Barchan sand dune in the coastal area of Saudi Arabia, by collecting samples and measurements from two vertically drilled boreholes up to the ground water level; one drilled in the dune crest and another one in the limb. Representative samples were collected and analyzed for their texture parameters, water content, and mineralogy. Electrical resistivity survey data was also acquired to map water content variation in the dune limb, and for comparison with well bore data. The reported results show no vertical variations in grain size or sorting in the dune crest. In contrast, the upper 0.5 m of the dune limb shows a relatively poorer sorting than found in deeper parts of the dune. Laterally, no variations in minerology were observed between crest and limb sands while grain size tended to be slightly coarser in the dune limb compared to the crest. Regarding the water content, it was found to vary vertically, probably due to previous cycles of rainfall infiltration through the sand body. Such observed variation in water content is consistent with the measured resistivity profile which could clearly identify the water table and areas with higher water content. This study concludes that beyond the upper 0.5 m, the Barchan sand dune body can be treated as a homogeneous medium in terms of mineralogy and sorting while grain size increases slightly toward the limb side.

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