Expanding networks of field hedges in densely populated landscapes in the Sahel
In: ISSN: 0378-1127 ; Forest Ecology and Management ; https://ird.hal.science/ird-02117954 ; Forest Ecology and Management, 2019, 440, pp.178-188. ⟨10.1016/j.foreco.2019.03.016⟩, 2019
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International audience ; Changing woody plant density across agricultural landscapes of the Sudano-Sahelian region is a debated issue. This paper reports the results of an investigation on the contribution of field hedges to overall woody plant density. Hedges separating individual cropped parcels were studied within village agropastoral territories in the Dantiandou district in western Niger. In 1992, field hedges were mapped over the study area using aerial photography and in 2016, using high resolution Google Earth imagery. In 1992, field hedge length was equal to 1006 km within 435 km 2 of croplands, equivalent to 2.3 km km −2. In 2016, 17.5% of these hedges had disappeared , but 1591 km of new hedges were observed resulting in an increased density of hedges to 5.6 km km −2. In 24 years, hedges had increased at a mean annual rate of 3.7% likely associated with the splitting of crop fields by inheritance. The composition and productivity of hedges were also monitored in 1996, 2010 and 2015. All trees (max-imum height ≥ 4 m), shrubs (< 4 m) and tussock perennial grasses were recorded within twelve field hedge samples of 200 m each. Field measurements were used to estimate basal area, crown area, foliage mass and wood mass of each woody plant within the sampled hedges. No significant trends were found between 1996 and 2015 in woody plant density, basal area, crown cover, wood and foliage masses across all monitored hedges. However, overall means hide a slight decrease in tree contributions, while shrub contributions first increased and then decreased. They also mask contradictory trends among sites most likely related to different rates of shrub coppicing and tree cutting. The woody species composition of the hedges is poor with an increase of Combretum glutinosum to the detriment of Guiera senegalensis over the study period. Multiplying the hedge sample statistics by the changing lengths of field hedges in the study area provides estimates of the contribution of the hedge woody plants to the woody plant ...
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Expanding networks of field hedges in densely populated landscapes in the Sahel
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Autor/in / Beteiligte Person: | Hiernaux, Pierre ; Adamou, Kalilou ; Moumouni, Oumarou ; Turner, Matthew, S ; Tong, Xiaoye ; Savadogo, Patrice ; Mougin, Éric ; Malam Issa, Oumarou ; Centre d'études spatiales de la biosphère (CESBIO) ; Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) ; Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP) ; Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE) ; University of Warwick Coventry ; Géosciences Environnement Toulouse (GET) ; Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS) ; Institut d'écologie et des sciences de l'environnement de Paris (iEES Paris) ; Institut National de la Recherche Agronomique (INRA)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS) ; observatory, AMMA-CATCH |
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Zeitschrift: | ISSN: 0378-1127 ; Forest Ecology and Management ; https://ird.hal.science/ird-02117954 ; Forest Ecology and Management, 2019, 440, pp.178-188. ⟨10.1016/j.foreco.2019.03.016⟩, 2019 |
Veröffentlichung: | HAL CCSD ; Elsevier, 2019 |
Medientyp: | academicJournal |
DOI: | 10.1016/j.foreco.2019.03.016 |
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