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Accueil du site → Master → Namibie → Environmental factors associated with Juttadinteria albata (L. Bolus) L. Bolus, population structure and assessment of its performance in trial planting at Sendelingsdrift mine

University of Namibia (2015)

Environmental factors associated with Juttadinteria albata (L. Bolus) L. Bolus, population structure and assessment of its performance in trial planting at Sendelingsdrift mine

Nauyoma, LT

Titre : Environmental factors associated with Juttadinteria albata (L. Bolus) L. Bolus, population structure and assessment of its performance in trial planting at Sendelingsdrift mine

Auteur : Nauyoma, LT

Université de soutenance : University of Namibia

Grade : Master of Science 2015

Résumé
Juttadinteria albata is a leaf succulent plant species endemic to the southern Namib in the Succulent Karoo in Sendelingsdrif near the Orange River. The proposed strip mining for diamonds at NAMDEB‟s new Sendelingsdrif mine may contribute to the loss of up to 39% of J. albata population. This may increase the risks of extinction for J. albata and species which may be interacting with it. The aim of the study was to investigate the biology of J. albata for ecological restoration post mining. The specific objectives of this study were to determine the relationship between infiltration rate, rockiness cover, slope angle, Aspect (the direction in which the slope faces), soil texture and soil elements that may be associated with J. albata in the study area ; to determine the population structure of J. albata in the study area, and to determine, as part of a trial planting, the most suitable post mining slopes and Aspects for the growth of J. albata that would be applied during its ecological restoration. The study was carried out through a field survey and a heap experiment. For the field survey, infiltration rate, slope angle, rockiness cover, soil texture and concentrations of soil elements in paired 4 m x 4 m quadrats were recorded. Canopy diameters, height and counts of live J. albata and Aspect were recorded in 4 m x 4 m quadrats where J. albata was found. Juttadinteria albata present in a total of 1,500, 2 m x 2 m quadrats were recorded to determine its spatial distribution pattern. Juttadinteria albata was grown on 12 experimental heaps in different Aspects and slopes. The results of the study revealed that quadrats where J. albata was found had significantly higher rockiness cover (t=6.40, df=40, P<0.001, paired t-test), slope angle (t=6.30, df=40, P<0.001) and organic carbon (t=3.84, df=23, P<0.01) than where it was not found. Juttadinteria albata was found in the western, southwestern, southern, southeastern, eastern, northeastern and level Aspects (F=1.38, df=6, P=0.26, One-way ANOVA test) in the study area because these Aspects are cool due to less intense sunlight exposure. Rocks capture primary sources of organic matter and steep slopes are effective at intercepting cool moist wind (moisture mainly from Orange River) resulting in favorable sites for J. albata on rocky steep slopes. Furthermore, J. albata followed a clumped spatial distribution pattern (variance=0.32>mean=0.07) in the study area. Juttadinteria albata plants could be capturing organic matter under their canopies or their dead parts resulted in higher concentrations of organic carbon in the soil which could possibly have also resulted in clumped distribution pattern. Finally, results showed that mean number of leaves of cuttings of J. albata in the level Aspect on the experimental heaps was significantly higher (F=6.07, df=8, P<0.001, ANOCOVA test) than those in the eastern, northeastern and northern Aspects at the end of heap experiment because these three Aspects are warm (e.g. northern Aspect receives more intense sunlight). Also, the mean canopy volume of cuttings of J. albata on steep slope was significantly higher (F=12.05, df=1, P<0.001, ANOCOVA test) than that on gentle slope experimental heaps at the end of heap experiment due to moisture on steep slopes. It is recommended that J. albata should be transplanted in clumped layouts on rocky steep slopes facing cool Aspects (as recorded in the present study) in mined areas with addition of organic mulch to post mining soils for organic carbon.

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Page publiée le 1er août 2015, mise à jour le 16 février 2018