Endowed with diverse vegetation covers, the Middle Atlas Mountains receive substantial snowfall i... more Endowed with diverse vegetation covers, the Middle Atlas Mountains receive substantial snowfall in winter, which contributes to plant hydration during the growing season. Using remotely-sensed imagery, this study aims to assess the trends in snow cover variations between 2000 and 2015, analyse the local influence of snowpack persistence on vegetation growth and evaluate the significance of this effect by comparing snow-fed and non-snow-fed sites. Trend analyses with Mann-Kendall and Ordinary Least-Squares (OLS) methods showed that, at the regional level, maximum Snow Cover Area (SCA) did not significantly change. However, fine scale analysis of SCA and Snow Cover Duration (SCD) along elevations and among basins revealed a pattern of increase in the mid-elevations, particularly in the range 2250 - 2500 m and the ocean-facing Sebou basin. This tendency was supported by significantly larger maximum SCAs in spring for Sebou and the region as a whole. With lower certainty, SCA and SCD al...
Situated between two densely populated cities, Rabat and Casablanca, Benslimane forest is subject... more Situated between two densely populated cities, Rabat and Casablanca, Benslimane forest is subject to diverse disturbances induced by the rising demographic pressure occurring in the region (land conversion for constructions and agricultural use, livestock farming, quarrying, fragmentation etc.). This study seeks to investigate the impacts of anthropogenic disturbances associated with urbanisation and farming on the woody vegetation of Benslimane forest. More specifically, it aims to characterise the organisation of woody plant communities and evaluate their structural and compositional change along an urban-rural gradient. TWINSPAN classification and Detrended Correspondence Analysis (DCA) ordination of the 36 plots surveyed distinguished three main communities, closely related to adjacent land uses and representing urban, rural and wild habitats. One-way ANOVA and Least Significant Difference (LSD) tests showed that forest patches adjoining built-up areas were significantly less rich in woody species than both rural-influenced and wilder interior patches. Spearman’s rank correlation test indicated that overall richness tended to decrease with the proximity of Benslimane town. Finally, DCA and Canonical Correspondence Analysis (CCA) ordinations, with environmental variables, showed that grazing and forest management were the most influential anthropogenic factors. Urban patches displayed a relatively healthy cork oak cover over a sparse understorey, rural patches comprised a more even and diverse community, while “wild” patches had a degraded overstorey but a richer and denser understorey. The abundance of the bushy Cistus monspelliensis, in association with cork oak mortality in supposed undisturbed areas, suggests a degenerative regional trend in community succession, from evergreen oak woodlands (as found in urban patches) to maquis (rural patches) then to / or to garrigue (“wild” patches).
Endowed with diverse vegetation covers, the Middle Atlas Mountains receive substantial snowfall i... more Endowed with diverse vegetation covers, the Middle Atlas Mountains receive substantial snowfall in winter, which contributes to plant hydration during the growing season. Using remotely-sensed imagery, this study aims to assess the trends in snow cover variations between 2000 and 2015, analyse the local influence of snowpack persistence on vegetation growth and evaluate the significance of this effect by comparing snow-fed and non-snow-fed sites. Trend analyses with Mann-Kendall and Ordinary Least-Squares (OLS) methods showed that, at the regional level, maximum Snow Cover Area (SCA) did not significantly change. However, fine scale analysis of SCA and Snow Cover Duration (SCD) along elevations and among basins revealed a pattern of increase in the mid-elevations, particularly in the range 2250 - 2500 m and the ocean-facing Sebou basin. This tendency was supported by significantly larger maximum SCAs in spring for Sebou and the region as a whole. With lower certainty, SCA and SCD also flagged a non-significant decrease in the low altitudes, particularly in the more continental south-facing zones of Oum Er-Rbia basin. Kendall Rank correlation between SCD and vegetation growth, as approximated with the Plant Phenology Index (PPI), indicated that, while non-prominent in the low elevations, plant sensitivity to snow increased in the mid-elevations, either positively, mainly in the wetter and more fertile windward plateaus, or negatively, essentially on ridges, complex terrains and on the drier and highly-drained Moulouya slopes. Forests were the most benefitting from snow, while shrublands appeared the most adversely impacted. Above a certain altitudinal threshold between 2000 and 2500 m, snow influence became drastically negative for all the vegetation types. Finally, using Kruskall-Wallis test and Mann–Whitney U pair-wise comparisons, the gradual strengthening of snow effect with duration was highlighted for a sample of shrublands located in the range 2000 - 2250 m in the rain-shadowed Moulouya basin.
Endowed with diverse vegetation covers, the Middle Atlas Mountains receive substantial snowfall i... more Endowed with diverse vegetation covers, the Middle Atlas Mountains receive substantial snowfall in winter, which contributes to plant hydration during the growing season. Using remotely-sensed imagery, this study aims to assess the trends in snow cover variations between 2000 and 2015, analyse the local influence of snowpack persistence on vegetation growth and evaluate the significance of this effect by comparing snow-fed and non-snow-fed sites. Trend analyses with Mann-Kendall and Ordinary Least-Squares (OLS) methods showed that, at the regional level, maximum Snow Cover Area (SCA) did not significantly change. However, fine scale analysis of SCA and Snow Cover Duration (SCD) along elevations and among basins revealed a pattern of increase in the mid-elevations, particularly in the range 2250 - 2500 m and the ocean-facing Sebou basin. This tendency was supported by significantly larger maximum SCAs in spring for Sebou and the region as a whole. With lower certainty, SCA and SCD al...
Situated between two densely populated cities, Rabat and Casablanca, Benslimane forest is subject... more Situated between two densely populated cities, Rabat and Casablanca, Benslimane forest is subject to diverse disturbances induced by the rising demographic pressure occurring in the region (land conversion for constructions and agricultural use, livestock farming, quarrying, fragmentation etc.). This study seeks to investigate the impacts of anthropogenic disturbances associated with urbanisation and farming on the woody vegetation of Benslimane forest. More specifically, it aims to characterise the organisation of woody plant communities and evaluate their structural and compositional change along an urban-rural gradient. TWINSPAN classification and Detrended Correspondence Analysis (DCA) ordination of the 36 plots surveyed distinguished three main communities, closely related to adjacent land uses and representing urban, rural and wild habitats. One-way ANOVA and Least Significant Difference (LSD) tests showed that forest patches adjoining built-up areas were significantly less rich in woody species than both rural-influenced and wilder interior patches. Spearman’s rank correlation test indicated that overall richness tended to decrease with the proximity of Benslimane town. Finally, DCA and Canonical Correspondence Analysis (CCA) ordinations, with environmental variables, showed that grazing and forest management were the most influential anthropogenic factors. Urban patches displayed a relatively healthy cork oak cover over a sparse understorey, rural patches comprised a more even and diverse community, while “wild” patches had a degraded overstorey but a richer and denser understorey. The abundance of the bushy Cistus monspelliensis, in association with cork oak mortality in supposed undisturbed areas, suggests a degenerative regional trend in community succession, from evergreen oak woodlands (as found in urban patches) to maquis (rural patches) then to / or to garrigue (“wild” patches).
Endowed with diverse vegetation covers, the Middle Atlas Mountains receive substantial snowfall i... more Endowed with diverse vegetation covers, the Middle Atlas Mountains receive substantial snowfall in winter, which contributes to plant hydration during the growing season. Using remotely-sensed imagery, this study aims to assess the trends in snow cover variations between 2000 and 2015, analyse the local influence of snowpack persistence on vegetation growth and evaluate the significance of this effect by comparing snow-fed and non-snow-fed sites. Trend analyses with Mann-Kendall and Ordinary Least-Squares (OLS) methods showed that, at the regional level, maximum Snow Cover Area (SCA) did not significantly change. However, fine scale analysis of SCA and Snow Cover Duration (SCD) along elevations and among basins revealed a pattern of increase in the mid-elevations, particularly in the range 2250 - 2500 m and the ocean-facing Sebou basin. This tendency was supported by significantly larger maximum SCAs in spring for Sebou and the region as a whole. With lower certainty, SCA and SCD also flagged a non-significant decrease in the low altitudes, particularly in the more continental south-facing zones of Oum Er-Rbia basin. Kendall Rank correlation between SCD and vegetation growth, as approximated with the Plant Phenology Index (PPI), indicated that, while non-prominent in the low elevations, plant sensitivity to snow increased in the mid-elevations, either positively, mainly in the wetter and more fertile windward plateaus, or negatively, essentially on ridges, complex terrains and on the drier and highly-drained Moulouya slopes. Forests were the most benefitting from snow, while shrublands appeared the most adversely impacted. Above a certain altitudinal threshold between 2000 and 2500 m, snow influence became drastically negative for all the vegetation types. Finally, using Kruskall-Wallis test and Mann–Whitney U pair-wise comparisons, the gradual strengthening of snow effect with duration was highlighted for a sample of shrublands located in the range 2000 - 2250 m in the rain-shadowed Moulouya basin.
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