Moisture and Salinity Drive the Vegetation Composition of Wadi Hargan, Riyadh, Saudi Arabia

Wetlands are represented in Saudi Arabia in the form of mangrove, sabkha, and wadi (valleys) systems, and these habitats are considered as a sanctuary for biodiversity. The present study aimed to identify different vegetation groups in a wetland site in Wadi Hargan near Alqurainah, Riyadh, Saudi Arabia, and to relate different plant communities and plant diversity to soil moisture, salinity, and other soil properties. Floristic analysis and vegetation structure were investigated within 15 stands along the wadi and were subjected to correlation analysis with soil factors via multivariate analysis. The floristic survey revealed the presence of 111 plant species belonging to 39 families. The most represented families were Asteraceae, Poaceae, Brassicaceae, Caryophyllaceae, and Papilionaceae, which accounted for the largest proportion (55.4%) of the total species. The therophytes were the dominant life form, where they were represented by 46.9% of the total number of species. The application of cluster analysis (TWINSPAN) to the importance value of each species based on the relative cover and density led to the recognition of four plant communities: (A) Phragmites australis—Tamarix nilotica community, (B) Zygophyllum coccineum—Acacia gerrardii community, (C) Lycium shawii—Zygophyllum coccineum community, and (D) Rhazya stricta community. The soil analysis and correlation test revealed significant variations in the content of salinity, moisture, CO3, Cl, SO4, Ca, Mg, and Na among the plant communities. It can be concluded that soil moisture and salinity factors were the fundamental driving forces for plant community structure in the studied wadi. The wadi was moderately grazed, mainly by camels; thereby, the invasive plant Rhazya stricta dominated the central region of the wadi. Also, human interference was observed at the end of the wadi, where some weeds sprouted such as Malva parviflora. The presence of those two rare wetland species, Adiantum capillus-veneris and Ficus salicifolia, in the study area, showed the unique properties of the studied wadi and necessitate an urgent biodiversity conservation action to protect its natural vegetation from overgrazing and human interference.

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Native Perennial Plants Colonizing Abandoned Arable Fields in a Desert Area: Population Structure and Community Assembly

Agriculture ◽

10.3390/agriculture10110550 ◽

2020 ◽

Vol 10 (11) ◽

pp. 550

Author(s):

Saud L. Al-Rowaily ◽

Dekhil H. Al-Dosari ◽

Abdulaziz M. Assaeed ◽

Ahmed M. Abd-ElGawad ◽

Mohamed A. El-Sheikh ◽

...

Keyword(s):

Saudi Arabia ◽

Population Structure ◽

Plant Communities ◽

Agricultural Land ◽

Soil Analysis ◽

Detrended Correspondence Analysis ◽

Reproductive Capacity ◽

Size Frequency Distribution ◽

Prosopis Farcta ◽

Arable Fields

In recent years, the phenomenon of abandonment of arable fields has increased in Saudi Arabia due to low soil fertility, drought, low rainfall, high levels of evapotranspiration, soil salinization, and low level of groundwater. We evaluated the effect of agricultural land abandonment on soil properties, perennial vegetation composition, and population structure in the Al-Kharj region, Saudi Arabia. A total of 11 perennial plant species belonging to 9 families and 11 genera were detected in the different abandoned fields of the study area. Four plant communities were identified after the application of the detrended correspondence analysis (DCA) ordination. The indicator species were (1) Seidlitzia rosmarinus—Zygophyllum hamiense, (2) Traganum nudatum—Seidlitzia rosmarinus, (3) Traganum nudatum—Prosopis farcta, and (4) Calligonum comosum—Pulicaria undulata. Results of the soil analysis showed significant differences in soil texture, pH, salinity, and nutrient content among the four recognized plant communities. Demographic analysis indicated that populations of Zygophyllum hamiense and Calligonum comosum tended to be either inverse J-shaped or positively skewed which may have indicated rapidly-growing populations with high reproductive capacity. Conversely, the size–frequency distribution of Traganum nudatum, S. Rosmarinus, and Prosopis farcta was approximately symmetrical (i.e., bell-shaped). The present study sheds light on the necessity of managing abandoned agricultural fields for restoring and improving rangelands with native species that are adapted to the local conditions such as low water demand.

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Floristic Variation of Tree Communities and Their Association with Soil Properties in Pulau Jerejak, Penang, Peninsular Malaysia

Science Letters ◽

10.24191/sl.v14i1.7899 ◽

2020 ◽

Vol 14 (1) ◽

pp. 34

Author(s):

Faezah Pardi

Keyword(s):

Tree Species ◽

Diversity Index ◽

Basal Area ◽

Peninsular Malaysia ◽

Importance Value ◽

Conservation Action ◽

Endangered Tree ◽

Endangered Tree Species ◽

Tree Communities ◽

Floristic Variation

This study was conducted at Pulau Jerejak, Penang to determine the floristic variation of its tree communities. A 0.5-hectare study plot was established and divided into 11 subplots. A total of 587 trees with diameter at breast height (DBH) of 5 cm and above were measured, identified and recorded. The tree communities comprised of 84 species, 63 genera and 32 families. The Myrtaceae was the most speciose family with 10 recorded species while Syzgium glaucum (Myrtaceae) was the most frequent species. The Myrtaceae recorded the highest density of 306 individuals while Syzgium glaucum (Myrtaceae) had the highest species density of 182 individuals. Total tree basal area (BA) was 21.47 m2/ha and family with the highest BA was Myrtaceae with 5.81 m2/ha while at species level, Syzgium glaucum (Myrtaceae) was the species with the highest total BA in the plot with value of 4.95 m2/ha. The Shannon˗Weiner Diversity Index of tree communities showed a value of 3.60 (H'max = 4.43) and Evenness Index of 0.81 which indicates high uniformity of tree species. The Margalef Richness Index (R') revealed that the tree species richness was 13.02. Myrtaceae had the highest Importance Value of 20.4%. The Canonical Correspondence Analysis (CCA) showed that Diospyros buxifolia (Ebenaceae) and Pouteria malaccensis (Sapotaceae) were strongly correlated to low pH. Dysoxylum cauliflorum (Meliaceae) and Eriobotrya bengalensis (Rosaceae) were correlated to phosphorus (P) and calcium ion (Ca2+), respectively. Therefore, the trees species composition at Pulau Jerejak showed that the biodiversity is high and conservation action should be implemented to protect endangered tree species. Keywords: Floristic variation; Tree communities; Trees composition; Pulau Jerejak; Species diversity

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Soil moisture variations in response to precipitation properties and plant communities on steep gully slope on the Loess Plateau

Agricultural Water Management ◽

10.1016/j.agwat.2021.107086 ◽

2021 ◽

Vol 256 ◽

pp. 107086

Author(s):

Pingzong Zhu ◽

Guanghui Zhang ◽

Hongxiao Wang ◽

Baojun Zhang ◽

Yingna Liu

Keyword(s):

Soil Moisture ◽

Loess Plateau ◽

Plant Communities ◽

The Loess Plateau

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Vegetation of the Witbank Nature Reserve and its importance for conservation of threatened Rocky Highveld Grassland

Koedoe ◽

10.4102/koedoe.v40i2.275 ◽

1997 ◽

Vol 40 (2) ◽

Cited By ~ 10

Author(s):

C.M. Smit ◽

G.J. Bredenkamp ◽

N. Van Rooyen ◽

A.E. Van Wyk ◽

J.M. Combrinck

Keyword(s):

Soil Moisture ◽

Plant Communities ◽

Nature Reserve ◽

Soil Depth ◽

Floristic Composition ◽

Diversity Indices ◽

Moisture Gradient ◽

Negative Effects ◽

Soil Moisture Gradient ◽

Great Escarpment

A vegetation survey of the Witbank Nature Reserve, comprising 847 hectares, was conducted. Phytosociological data were used to identify plant communities, as well as to determine alpha and beta diversities. Eleven plant communities were recognised, two of these are subdivided into sub- communities, resulting in 14 vegetation units. These communities represent four main vegetation types, namely grassland, woodland, wetland and disturbed vegetation. Grassland communities have the highest plant diversity and wetland vegetation the lowest. Floristic composition indicates that the vegetation of the Rocky Highveld Grassland has affinities to the grassland and savanna biomes and also to the Afromontane vegetation of the Great Escarpment. An ordination scatter diagram shows the distribution of the 14 plant communities or sub-communities along a soil moisture gradient, as well as along a soil depth/surface rock gradient. The sequence of communities along the soil moisture gradient is used for calculating beta-diversity indices. It is concluded that the relatively small size of the Witbank Nature Reserve is unlikely to have significant negative effects on the phytodiversity of the various plant communities. This nature reserve is therefore of considerable importance in conserving a representative sample of the Rocky Highveld Grassland.

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Using Microwave Soil Heating to Inhibit Invasive Species Seed Germination

Invasive Plant Science and Management ◽

10.1017/inp.2017.29 ◽

2017 ◽

Vol 10 (3) ◽

pp. 262-270 ◽

Cited By ~ 7

Author(s):

Mélissa De Wilde ◽

Elise Buisson ◽

Nicole Yavercovski ◽

Loïc Willm ◽

Livia Bieder ◽

...

Keyword(s):

Invasive Species ◽

Soil Moisture ◽

Seed Germination ◽

Invasive Plant ◽

Organic Matter Content ◽

Seed Viability ◽

Germination Percentage ◽

Matter Content ◽

Burial Depth ◽

Experimental Conditions

Successful invasive plant eradication is rare, because the methods used target the adult stage, not taking into account the development capacity of a large seedbank. Heating by microwave was considered, because it offers a means to quickly reach the temperature required for loss of seed viability and inhibition of germination. Previous results were not encouraging, because homogeneous and deep-wave penetration was not achieved, and the various parameters that can affect treatment effectiveness were incompletely addressed. This study aimed to determine, under experimental conditions, the best microwave treatment to inhibit invasive species seed germination in terms of power (2, 4, 6 kW) and duration (2, 4, 8 min) of treatments and depending on soil moisture (10%, 13%, 20%, 30%) and seed burial depth (2, 12 cm). Three invasive species were tested: Bohemian knotweed, giant goldenrod, and jimsonweed. The most effective treatments required relatively high power and duration (2kW8min, 4kW4min, 6kW2min, and 6kW4min; 4kW8min and 6kW8min were not tested for technical reasons), and their effectiveness diminished with increasing soil moisture with germination percentage between 0% and 2% for the lowest soil moisture, 0% and 56% for intermediate soil moisture, and 27% and 68% in control treatments. For the highest soil moisture, only 2kW8min and 4kW4min reduced germination percentage between 2% and 19%. Occasionally, germination of seeds located at the 12-cm depth was more strongly affected. Giant goldenrod seeds were the most sensitive, probably due to their small size. Results are promising and justify further experiments before developing a field microwave device to treat large volumes of soil infested by invasive seed efficiently and with reasonable energy requirements. Other types of soil, in terms of texture and organic matter content, should be tested in future experiments, because these factors influence soil water content and, consequently, microwave heating.

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Populations of Heracleum sosnowskyi and H. mantegazzianum (Apiaceae) in Kyiv (Ukraine)

Folia Oecologica ◽

10.2478/foecol-2021-0022 ◽

2021 ◽

Vol 48 (2) ◽

pp. 215-228

Author(s):

Lubov Gubar ◽

Serhii Koniakin

Keyword(s):

Plant Communities ◽

Invasive Plant ◽

Negative Impact ◽

Urban Ecosystems ◽

Heracleum Sosnowskyi ◽

Secondary Range ◽

Natural Range ◽

The Difference ◽

Moisture Conditions ◽

Ruderal Plant

Abstract In connection with the increasing negative impact of invasive alien species on biodiversity and the environment in general, their research, as well as throughout the world, is relevant. The distribution of the Heracleum sosnowskyi and H. mantegazzianum of the secondary range on the example of the Kyiv agglomeration is investigated in the work. In our study we aimed to evaluate the possibility of spontaneous spread of giant hogweeds in the secondary range, adaptation of the species to the new conditions of the environment that favor to control of these species’ expansion and reduce the threat to the urban ecosystems and citizens’ health. We hypothesise that in the secondary range H. sosnowskyi and H. mantegazzianum settle sites with relatively high temperature (Tr), lightening (Lc), and soil moisture conditions similar to that in their natural range. 17 populations and four localities (sites) of H. sosnowskyi and H. mantegazzianum were studied. They were found within forest, meadow, riverine and ruderal plant communities. It is indicated that the advent species fully adapted to the conditions of the environment. The difference by ecological indicators Lc2 and Tm1 is pointed out. According to the results of our research, for the area of Kyiv urban agglomeration the growth of H. sosnowskyi and H. mantegazzianum is indicated in the plants communities of six classes. They spread most in ruderal plant communities of the: Robinietea, Artemisietea, Epilobietea classes. The studied species belong to invasive plant species in Ukraine and are characterized by extremely high effect on the environment and high invasive potential.

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Elemental Enrichment in Shallow Subsurface Red Sea Coastal Sediments, Al-Shuaiba, Saudi Arabia: Natural vs. Anthropogenic Controls

Minerals ◽

10.3390/min11080898 ◽

2021 ◽

Vol 11 (8) ◽

pp. 898

Author(s):

Ibrahim M. Ghandour ◽

Mohammed H. Aljahdali

Keyword(s):

Saudi Arabia ◽

Red Sea ◽

Driving Forces ◽

Road Construction ◽

Coastal Sediments ◽

Medieval Climate Anomaly ◽

Climate Anomaly ◽

Shallow Subsurface ◽

The Road ◽

The Core

Geochemical analysis of the 23 sediment samples collected from a short (0.6 m long) core retrieved from the coastal creek that was previously connecting the northern and southern Al-Shuaiba Lagoons, Red Sea, Saudi Arabia, was accomplished to assess the elemental enrichment levels and the natural and anthropogenic driving forces for this enrichment. Statistical analysis and upcore variation in elemental concentrations enabled subdivision of the core formally into three units, lower, middle, and upper. The enriched elements in the lower and middle units display poor to negative correlations with the enriched elements in the upper unit. The lower unit is enriched in elements (Mo, As, U, and Re) suggesting deposition under anoxic conditions, possibly related to the Medieval Climate Anomaly. The middle unit is enriched in the carbonate-related constituents (CaCO3, Ca, and Sr). The upper unit is enriched in elements that co-vary significantly with Al suggesting increased terrigenous supply associated with the construction of the road between the two lagoons. The enrichment of elements in the lower and middle units is naturally driven, whereas the enrichment of lithogenic elements in the upper unit, though of geogenic origin, is induced after the road construction.

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Does Altering Local Water Availability for an Invasive Plant (Raphanus raphanistrum) Affect Floral Morphology and Reproductive Potential?

American Journal of Undergraduate Research ◽

10.33697/ajur.2015.008 ◽

2015 ◽

Vol 12 (2) ◽

Cited By ~ 2

Author(s):

Natalia Pirimova ◽

Alison Parker ◽

Lesley Campbell

Keyword(s):

Soil Moisture ◽

Foraging Behavior ◽

Water Availability ◽

Community Dynamics ◽

Invasive Plant ◽

Floral Morphology ◽

Insect Community ◽

Raphanus Raphanistrum ◽

Anther Length ◽

Corolla Diameter

Abiotic environmental variation can have dramatic effects on plant floral morphology and nectar or pollen rewards. In response, pollinators may change their foraging behavior and distribution and if pollinators change their foraging behavior or distribution, this could have dramatic effects on the reproductive success of plant populations. To start tackling this problem, we measured the response of floral morphology (corolla diameter, stamen length, and ovule number) of Raphanus raphanistrum to experimental manipulations of field soil moisture. As soil moisture increased, corolla diameter and anther length grew. We expect these changes to provide more visitation rewards for insects in moist conditions. Therefore, water availability influences growth and development of flowers, and may have dramatic effects on insect community dynamics. KEYWORDS: Floral Rewards, Climate, Rain-out Shelters, Flower Morphology, Raphanus raphanistrum, Brassicaceae

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