@article{fdi:010075844,
  title = {{E}xpanding networks of field hedges in densely populated landscapes in the {S}ahel},
  author = {{H}iernaux, {P}. and {A}damou, {K}. and {M}oumouni, {O}. and {T}urner, {M}.{D}. and {T}ong, {X}. and {S}avadogo, {P}. and {M}ougin, {E}. and {M}alam {I}ssa, {O}umarou},
  editor = {},
  language = {{ENG}},
  abstract = {{C}hanging woody plant density across agricultural landscapes of the {S}udano-{S}ahelian region is a debated issue. {T}his paper reports the results of an investigation on the contribution of field hedges to overall woody plant density. {H}edges separating individual cropped parcels were studied within village agropastoral territories in the {D}antiandou district in western {N}iger. {I}n 1992, field hedges were mapped over the study area using aerial photography and in 2016, using high resolution {G}oogle {E}arth imagery. {I}n 1992, field hedge length was equal to 1006 km within 435 km(2) of croplands, equivalent to 2.3 km km(-2). {I}n 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). {I}n 24 years, hedges had increased at a mean annual rate of 3.7% likely associated with the splitting of crop fields by inheritance. {T}he composition and productivity of hedges were also monitored in 1996, 2010 and 2015. {A}ll trees (maximum height >= 4 m), shrubs (< 4 m) and tussock perennial grasses were recorded within twelve field hedge samples of 200 m each. {F}ield measurements were used to estimate basal area, crown area, foliage mass and wood mass of each woody plant within the sampled hedges. {N}o significant trends were found between 1996 and 2015 in woody plant density, basal area, crown cover, wood and foliage masses across all monitored hedges. {H}owever, overall means hide a slight decrease in tree contributions, while shrub contributions first increased and then decreased. {T}hey also mask contradictory trends among sites most likely related to different rates of shrub coppicing and tree cutting. {T}he woody species composition of the hedges is poor with an increase of {C}ombretum giutinosum to the detriment of {G}uiera senegalensis over the study period. {M}ultiplying 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 population at a landscape scale. {B}etween 1992 and 2016, field hedges contributed to increases of woody plant density by 3.9%, basal areas by 5.4%, crown cover by 2.7%, leading to 6.1% annual increase in foliage mass and 8.8% increase in wood mass.},
  keywords = {{ZONE} {SAHELIENNE} ; {NIGER}},
  booktitle = {},
  journal = {{F}orest {E}cology and {M}anagement},
  volume = {440},
  numero = {},
  pages = {178--188},
  ISSN = {0378-1127},
  year = {2019},
  DOI = {10.1016/j.foreco.2019.03.016},
  URL = {https://www.documentation.ird.fr/hor/fdi:010075844},
}