Tropical Montane Forest Conversion Is a Critical Driver for Sediment Supply in East African Catchments
Land use change is known to affect suspended sediment fluxes in headwater catchments. There is however limited empirical evidence of the magnitude of these effects for montane catchments in East Africa. We collected a unique 4-year high-frequency data set and assessed seasonal sediment variation, wa...
| Autores principales: | , , , , , |
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| Formato: | Journal Article |
| Lenguaje: | Inglés |
| Publicado: |
American Geophysical Union
2020
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| Materias: | |
| Acceso en línea: | https://hdl.handle.net/10568/114018 |
| _version_ | 1855520555496636416 |
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| author | Stenfert Kroese, J. Jacobs, S.R. Tych, W. Breuer, Lutz Quinton, J.N. Rufino, Mariana C. |
| author_browse | Breuer, Lutz Jacobs, S.R. Quinton, J.N. Rufino, Mariana C. Stenfert Kroese, J. Tych, W. |
| author_facet | Stenfert Kroese, J. Jacobs, S.R. Tych, W. Breuer, Lutz Quinton, J.N. Rufino, Mariana C. |
| author_sort | Stenfert Kroese, J. |
| collection | Repository of Agricultural Research Outputs (CGSpace) |
| description | Land use change is known to affect suspended sediment fluxes in headwater catchments. There is however limited empirical evidence of the magnitude of these effects for montane catchments in East Africa. We collected a unique 4-year high-frequency data set and assessed seasonal sediment variation, water pathways, and sediment response to hydrology in three catchments under contrasting land use in the Mau Forest Complex, Kenya's largest tropical montane forest. Annual suspended sediment yield was significantly higher in a smallholder agriculture-dominated catchment (131.5 ± 90.6 t km−2 yr−1) than in a tea-tree plantation catchment (42.0 ± 21.0 t km−2 yr−1) and a natural forest catchment (21.5 ± 11.1 t km−2 yr−1) (p < 0.05). Transfer function models showed that in the natural forest and the tea-tree plantations subsurface flow pathways delivered water to the stream, while in the smallholder agriculture shallow subsurface and surface runoff were dominant. There was a delayed sediment response to rainfall for the smallholder agriculture and the tea-tree plantations. A slow depletion in sediment supply suggests that the wider catchment area supplies sediment, especially in the catchment dominated by smallholder farming. In contrast, a fast sediment response and depletion in sediment supply in the natural forest suggests a dominance of temporarily stored and nearby sediment sources. This study shows that the vegetation cover of a forest ecosystem is very effective in conserving soil, whereas catchments with more bare soil and poor soil conservation practices generated six times more suspended sediment yield. Catchment connectivity through unpaved tracks is thought to be the main explanation for the difference in sediment yield. |
| format | Journal Article |
| id | CGSpace114018 |
| institution | CGIAR Consortium |
| language | Inglés |
| publishDate | 2020 |
| publishDateRange | 2020 |
| publishDateSort | 2020 |
| publisher | American Geophysical Union |
| publisherStr | American Geophysical Union |
| record_format | dspace |
| spelling | CGSpace1140182025-12-08T09:54:28Z Tropical Montane Forest Conversion Is a Critical Driver for Sediment Supply in East African Catchments Stenfert Kroese, J. Jacobs, S.R. Tych, W. Breuer, Lutz Quinton, J.N. Rufino, Mariana C. catchment hydrology watershed management tropical forests agriculture Land use change is known to affect suspended sediment fluxes in headwater catchments. There is however limited empirical evidence of the magnitude of these effects for montane catchments in East Africa. We collected a unique 4-year high-frequency data set and assessed seasonal sediment variation, water pathways, and sediment response to hydrology in three catchments under contrasting land use in the Mau Forest Complex, Kenya's largest tropical montane forest. Annual suspended sediment yield was significantly higher in a smallholder agriculture-dominated catchment (131.5 ± 90.6 t km−2 yr−1) than in a tea-tree plantation catchment (42.0 ± 21.0 t km−2 yr−1) and a natural forest catchment (21.5 ± 11.1 t km−2 yr−1) (p < 0.05). Transfer function models showed that in the natural forest and the tea-tree plantations subsurface flow pathways delivered water to the stream, while in the smallholder agriculture shallow subsurface and surface runoff were dominant. There was a delayed sediment response to rainfall for the smallholder agriculture and the tea-tree plantations. A slow depletion in sediment supply suggests that the wider catchment area supplies sediment, especially in the catchment dominated by smallholder farming. In contrast, a fast sediment response and depletion in sediment supply in the natural forest suggests a dominance of temporarily stored and nearby sediment sources. This study shows that the vegetation cover of a forest ecosystem is very effective in conserving soil, whereas catchments with more bare soil and poor soil conservation practices generated six times more suspended sediment yield. Catchment connectivity through unpaved tracks is thought to be the main explanation for the difference in sediment yield. 2020-10 2021-01-21T01:20:56Z 2021-01-21T01:20:56Z Journal Article https://hdl.handle.net/10568/114018 en Open Access American Geophysical Union Stenfert Kroese, J., Jacobs, S.R., Tych, W., Breuer, L., Quinton, J.N., & Rufino, M.C. 2020. Tropical montane forest conversion is a critical driver for sediment supply in East African catchments. Water Resources Research, 56: e2020WR027495. https://doi.org/10.1029/2020WR027495 |
| spellingShingle | catchment hydrology watershed management tropical forests agriculture Stenfert Kroese, J. Jacobs, S.R. Tych, W. Breuer, Lutz Quinton, J.N. Rufino, Mariana C. Tropical Montane Forest Conversion Is a Critical Driver for Sediment Supply in East African Catchments |
| title | Tropical Montane Forest Conversion Is a Critical Driver for Sediment Supply in East African Catchments |
| title_full | Tropical Montane Forest Conversion Is a Critical Driver for Sediment Supply in East African Catchments |
| title_fullStr | Tropical Montane Forest Conversion Is a Critical Driver for Sediment Supply in East African Catchments |
| title_full_unstemmed | Tropical Montane Forest Conversion Is a Critical Driver for Sediment Supply in East African Catchments |
| title_short | Tropical Montane Forest Conversion Is a Critical Driver for Sediment Supply in East African Catchments |
| title_sort | tropical montane forest conversion is a critical driver for sediment supply in east african catchments |
| topic | catchment hydrology watershed management tropical forests agriculture |
| url | https://hdl.handle.net/10568/114018 |
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