Contribution to the phytoecological study of the biodiversity of the dune cord of El-Mesrane in the Wilaya (Province) of Djelfa in Algeria

The various dune fixation actions began in 1982 in the study area (El Mesrane –Djelfa) at the level of the dune ridge with very interesting results, on the one hand for the control of desertification through the creation of a microclimate that ensures the ecological sustainability of fragile ecosystems. This work was carried out in the two projects (1) and (2) in the study area. The objective of the study is summarized in the floristic and ecological char-acterization of the vegetation subject to fixation and other left without fixa-tion or natural regeneration. These dunes have a poorer floristic diversity than those fixed by Retama Retam webb and Tamarix gallica. A significant diversity of 26 species was encountered on dunes naturally fixed by vegeta-tion.The Shannon-Weiner diversity index for the vegetation of natural fixa-tion was found to be H’= 2.05; however, this index for dunes naturally fixed by Retama retam and Tamarix gallicawas 2,61 and 2,5, respectively. In gen-eral, dicotyledonous plant families such as the Asteraceae, Fabaceae and Poaceae were mostly encountered. Moreover, the distribution of biologic types is mainly characterized by the predominance of Chamephytes and The-rophytes. The degradation of the environment due to the anthropogenic pressure favors the high presence of Therophytes. These findings allowed deducing that the degradation of vegetation is mainly attributed to climatic conditions and overgrazing.

Importance ethnobotanique de Leptadenia pyrotechnica (Forssk.) Decne. dans le département de Diffa au Niger

En zone sahélienne où les ressources ligneuses sont relativement rares, l’espèce Leptadenia pyrotechnica joue un rôle très important dans la vie des populations locales. La présente étude dont l’objectif est de répertorier les connaissances locales sur les modes d’utilisation et de gestion des peuplements naturels par les populations locale de Leptadenia pyrotechnica a été conduite dans la région de Diffa. Des enquêtes ethnobotaniques ont été conduites au niveau de cinq villages. Il s’agit de: Issari; Guelborno Mounimari, Jalori, Joulou Kriyé et le marché de Digurdi. Dans l’ensemble des villages, un total de 150 personnes a été interviewé à travers des entretiens individuels. Les principales rubriques du questionnaire administré sont relatives aux principales utilisations et leur impact sur la ressource. Il ressort de l’étude que toutes les parties de Leptadenia pyrotechnica (feuilles; rameaux, tiges, racines, écorce et la sève) sont utilisées par les différents groupes ethniques et socioprofessionnels de la zone d’étude (Haoussa, Peulh et Kanouri). Cependant, la connaissance de l’importance et les différentes catégories d’utilisation dépendent d’un groupe à un autre. Les principales catégories d’utilisations dénombrées dans le cadre de la présente étude sont: l’utilisation comme bois énergie, fixation des dunes, fourrage et pharmacopée traditionnelle. La fixation des dunes et la transhumance s’avèrent être les principaux facteurs limitant la disponibilité de cette espèce. Pour une conservation durable de l’espèce, une norme de prélèvement de Leptadenia pyrotechnica doit être définie pour la fixation des dunes et la capacité de charge des formations à Leptadenia pyrotechnica doit être contrôlée vis-à-vis des transhumances. © 2020 International Formulae Group. All rights reserved. Mots clés: Leptadenia pyrotechnica, utilisation, bois, sève, rameaux, racine English Title: Ethnobotanical importance of Leptadenia pyrotechnica Forsk. in the department of Diffa in Niger English Abstract In the Sahelian zone where wood resources are relatively rare, the species Leptadenia pyrotechnica plays a very important role in the lives of local populations. The purpose of this study, which is to identify local knowledge on the use and management of natural stands by local populations of Leptadenia pyrotechnica, was conducted in Diffa region. Ethnobotanical surveys were conducted at five villages. These are: Issari; Guelborno Mounimari, Jalori, Joulou Kriyé and Digurdi market. In all the villages, a total of 150 people were interviewed through individual interviews. The main sections of the questionnaire administered relate to the main uses and their impact on the resource. The study shows that all parts of Leptadenia pyrotechnica (leaves, twigs, stems, roots, bark and sap) are used by the different ethnic and socio-occupational groups in the study area (Hausa, Fulani and Kanuri). However, knowledge of importance and the different categories of use depend on one group to another. The main categories of uses enumerated in this study are: wood energy use, dune fixation, fodder and traditional pharmacopoeia. The fixation of the dunes and the transhumance appear to be the main factors limiting the availability of this species. For a sustainable conservation of the species, a Leptadenia pyrotechnica sampling standard must be defined for the fixation of the dunes and the carrying capacity of Leptadenia pyrotechnica formations must be checked against transhumance. © 2020 International Formulae Group. All rights reserved. Keywords: Leptadenia pyrotechnica, use, wood, sap, twigs, root

Can Vegetation Removal Successfully Restore Coastal Dune Biodiversity?

Coastal dune habitats have been declining globally over the last several decades due to rapid urbanization. Within remaining dune systems, dune fixation has resulted in further losses of mobile dunes with negative impacts on their associated species. Some studies suggest vegetation removal can initially promote habitat heterogeneity, and increase availability of suitable habitats for psammophile, xeric and endemic mobile dune species, but longer-term responses are generally unknown. We investigated the temporal trends of four taxonomic groups to determine the effect of vegetation removal on dune assemblages over a 12-year period at an LTER site. Three different forms of removal are investigated here—removal in a grid form on fixed dunes, removal of the wind-facing slope vegetation on semi-fixed dunes and opportunistic off-road driving on disturbed dunes. Results were varied across taxa, highlighting the need for multi-taxa monitoring in conservation and restoration management. Overall, fixed dune treatment had very little effect, while a stronger response was found in semi-fixed treatments in particular for mobile dune indicator species, which showed evidence of recolonization within a few years following treatment. Disturbed dunes were most similar to mobile dunes for animal taxa indicating that pulse removal may not be as effective as continuous press disturbance. Nevertheless, a less destructive form of disturbance such as re-introduction of grazing might be preferable and requires further investigation.

Regeneration and Early Tending of Black Locust (Robinia pseudoacacia L.) Stands in the North-West of Romania

Background and Purpose: The aim of this study is to highlight the importance of black locust (Robinia pseudoacacia L.), a North American-originating tree species of major importance in Romania, in extreme site conditions such as sand dunes. In this respect, a Research and Development (R&D) project has been carried out in Carei-Valea lui Mihai Plain (north-west of Romania) since 2016. Materials and Methods: Three sub-compartments were selected in IV Valea lui Mihai Working Circle, Săcueni Forest District: two pure natural regenerations by root suckers of black locust at different ages (sub-compartments 3B and 52A%) and a mixed black locust - black cherry stand (sub-compartment 23D). Biometrical measurements and analyses as well as biomass estimations were performed. A thorough statistical analysis using the data on initial, extracted and residual trees/stands was also performed. Results: The main outputs of the project are as follows: (1) Black locust was established naturally by root suckers and the stocking of newly established stands can be as high as 50,000 suckers·ha-1; (2) The initial growth of black locust regeneration is quick and the young regeneration can close the canopy in 1-2 years, resulting in an appropriate dune fixation and wind erosion control; (3) The young pure or mixed black locust-dominated stands are left untended until the first cleaning-respacing (mean diameter 5-6 cm), when the stand shows high stocking/density and a wide variation in tree size. This intervention is from below, heavy (intensity over 25% by number of trees or basal area) and of negative selection type, removing mostly low Kraft’s class, dead or dying, and defective trees. Conclusions: This R&D project has shown the high potential of black locust to establish naturally by root suckers after a low coppice cut and stump removal, as well as the fast initial growth of regenerated black locust. The quick canopy closure of young regeneration results in an appropriate dune fixation and wind erosion control.

Landsat thermal band efficiency on characterizing mulched soil surface

Landsat thermal band efficiency on characterizing mulched soil surface In order to study petroleum mulch effects on soil, and sand dune fixation, thermal, and reflective bands of Landsat thematic mapper TM and ETM data, and other sources of information including topographic maps, aerial photos, and field work were used. The methodology was comprised of: images processing, statistic analysis, and relationship between thermal and reflective data. The results from image processing show that the behaviour of the Landsat thermal data is completely different from reflective data. The results from colour composite images including thermal bands have shown the capability of thermal bands in reparability of mulched and non-mulched areas. It was generally concluded that selection of TM, ETM thermal band is an important step to evaluate the area covered with petroleum mulch. Ratio mulch index was introduced as a best band combination in order to imagine mulch decomposition.