%0 Journal Article
%T The effects of human land use on flow regime and water chemistry of headwater streams in the highlands of Chiapas Les effets de l¡¯utilisation des terres sur le r¨¦gime d¡¯¨¦coulement et la composition chimique de l¡¯eau des ruisseaux de t¨ºte de bassin des plateaux du Chiapas
%A Castillo M.M.
%A Morales H.
%A Valencia E.
%A Morales J.J.
%J Knowledge and Management of Aquatic Ecosystems
%D 2013
%I EDP Sciences
%R 10.1051/kmae/2013035
%X We studied the effects of land use changes on flow regime and water chemistry of headwater streams in the highlands of Chiapas, a region in southern Mexico that has experienced high rates of deforestation in the last decades. Samples for water chemistry were collected and discharge was measured between September 2007 and August 2008 at eight streams that differed in the land uses of their riparian and catchment areas, including streams draining protected forested areas. Streams with high forest cover (>70%) in their catchments maintained flow through the year. Streams draining more disturbed catchments exhibited reduced or no flow for 4   6 months during the dry season. Nitrate concentrations were lower at streams draining forested catchments while highest concentrations were measured where conventional agriculture covered a high proportion of the catchment and riparian zone. Highest phosphorus concentrations occurred at the catchment where poultry manure was applied as fertilizer. Differences between forest streams and those draining disturbed areas were correlated with the proportion of forest and agriculture in the riparian zone. Variation in stream variables among sampling dates was lower at the forest sites than at the more disturbed study streams. Conversion of forest into agriculture and urban areas is affecting flow regime and increasing nutrient concentrations, although the magnitude of the impacts are influenced by the type of agricultural practices and the alteration of the riparian zone. Nous avons ¨¦tudi¨¦ l¡¯influence des changements d¡¯am¨¦nagement du territoire sur le r¨¦gime hydrographique et la composition hydrochimique de ruisseaux des plateaux du Chiapas, une r¨¦gion au sud du Mexique qui a subi une d¨¦forestation de grande ampleur ces derni¨¨res d¨¦cennies. Entre septembre 2007 et ao t 2008, nous avons pr¨¦lev¨¦ des ¨¦chantillons d¡¯eau et avons mesur¨¦ l¡¯¨¦coulement au niveau de 8 ruisseaux, qui diff¨¦raient par l¡¯utilisation des terres de leurs bassins versants et de leurs zones riveraines; ceci incluait des ruisseaux drainant des zones foresti¨¨res prot¨¦g¨¦es. Les ruisseaux avec une couverture foresti¨¨re importante dans leurs bassins versants (>70 %) ¨¦taient en eau toute l¡¯ann¨¦e. Les cours d¡¯eau drainant des bassins versants plus antropis¨¦s montraient une r¨¦duction ou non du flux durant 4 ¨¤ 6 mois lors de la saison s¨¨che. Les concentrations en nitrates ¨¦taient plus basses dans les ruisseaux drainant des bassins versants forestiers tandis que les plus hautes concentrations furent mesur¨¦es lorsque l¡¯agriculture conventionnelle occupait une partie imp
%K stream
%K catchment
%K land use
%K nutrient enrichment
%K abstraction
%K ruisseau
%K bassin versant
%K am¨¦nagement du territoire
%K eutrophisation
%K captage d'eau
%U http://dx.doi.org/10.1051/kmae/2013035