Evaluation of Plant Diversity in the Steppes of White Wormwood of the Region of Saida (Western Algeria)

The botanical composition of grasslands determines the agronomic and natural values of swards. Good grassland management usually improves herbage value, but on the other hand it frequently decreases the plant diversity and species richness in the swards. In 1999 a field trial in a split-plot design with four replicates was therefore established on the Arrhenatherion type of vegetation in Ljubljana marsh meadows in order to investigate this relationship. Cutting regimes (2 cuts — with normal and delayed first cut, 3 cuts and 4 cuts per year) were allocated to the main plots and fertiliser treatments (zero fertiliser — control, PK and NPK with 2 or 3 N rates) were allocated to the sub-plots. The results at the 1 st cutting in the 5 th trial year were as follows: Fertilising either with PK or NPK had no significant negative effect on plant diversity in any of the cutting regimes. In most treatments the plant number even increased slightly compared to the control. On average, 20 species were listed on both unfertilised and fertilised swards. At this low to moderate level of exploitation intensity, the increased number of cuts had no significant negative effect on plant diversity either (19 species at 2 cuts vs. 20 species at 3 or 4 cuts). PK fertilisation increased the proportion of legumes in the herbage in the case of 2 or 3 cuts. The proportion of grasses in the herbage increased in all the fertilisation treatments with an increased numbers of cuts. Fertiliser treatment considerably reduced the proportion of marsh horsetail ( Equisetum palustre ) in the herbage of the meadows. This effect was even more pronounced at higher cut numbers. The proportion of Equisetum palustre in the herbage was the highest in the unfertilised sward with 2 cuts (26.4 %) and the lowest in the NPK-fertilised sward with 4 cuts (1.4%).

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Effects of land use and plant diversity on insect diversity and consequences for ecosystem functioning

10.1603/ice.2016.90841 ◽

2016 ◽

Author(s):

Wolfgang Weisser

Keyword(s):

Land Use ◽

Plant Diversity ◽

Ecosystem Functioning ◽

Insect Diversity ◽

Effects Of Land Use

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Impacts of anthropogenic pressure on the degradation of the forest of Doui Thabet (Saida, Western Algeria) in the context of the restoration

Acta Scientifica Naturalis ◽

10.2478/asn-2020-0022 ◽

2020 ◽

Vol 7 (2) ◽

pp. 88-97

Author(s):

Aouadj Sid Ahmed ◽

Nasrallah Yahia ◽

Hasnaoui Okkacha ◽

Khatir Hadj

Keyword(s):

Limiting Factor ◽

Global Changes ◽

Anthropogenic Pressure ◽

Qualitative And Quantitative ◽

Pressure Index ◽

High Plateau ◽

The Face ◽

Western Algeria ◽

Restoration Strategies ◽

Very High

AbstractThe forest of Doui Thabet is one of the forests of the Mounts of Saida (Western Algeria) which is experiencing a dynamic regressive. Located in the semi-arid bioclimatic stage, it is located at the edge of two phytogeographic sub-sectors: atlas Tellien Oranais (O3) and high plateau subsector (H1). Among the factors that threaten to curb this fragile and weakened ecosystem, in addition to drought and climate aridity and which has become a structural ecological phenomenon; the overgrazing is also a major limiting factor. This current study provides a qualitative and quantitative assessment of anthropogenic pressure exerted in this area zone. The methodology adopted in this study is that of Le Houerou (1969) and Montoya (1983), which it is based on the calculation of the annual needs of the herd in forage units, the estimate of the feed potential of production, the coefficient of overgrazing and in addition to the anthropogenic pressure index. The result of the forage balance in the forest rangelands of the studied area has a forage deficit (overload) of (96.64%) (a sylvopastoral imbalance), in addition to that, the coefficient of overgrazing is (92.3%) and the anthropogenic pressure index is very high (28). The conservation and the restoration of this area is a major concern in the face of global changes, taking into account their mode of reproduction and their dynamics, for the development of restoration strategies and more effective ways of protection.

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