Inventorying management status and plant species richness in semi-natural grasslands using high spatial resolution imagery

TY - JOUR

T1 - Inventorying management status and plant species richness in semi-natural grasslands using high spatial resolution imagery

AU - Hall, Karin

AU - Jönsson, Lotten

AU - Sykes, Martin

AU - Reitalu, Triin

AU - Larsson, Karin

AU - Prentice, Honor C

PY - 2010

Y1 - 2010

N2 - Question Can we reliably estimate grazing intensity, indicators of grazing intensity (i.e. field-layer height and shrub-cover), and vascular plant species richness in semi-natural grasslands from high spatial resolution satellite data? Location The Baltic Island of Oland (Sweden). Methods Fieldwork included the on-site description of grazed and ungrazed areas and shrub-cover within 107 semi-natural grassland sites. Field-layer height and vascular plant species richness (total within-site and mean small-scale species richness) were recorded within the sites. Digital classification of QuickBird data was performed to identify grazed and ungrazed areas and shrub-cover. Vegetation indices were generated to analyze the performance of satellite data for estimating field-layer height, and the spectral heterogeneity was used to characterize the within-site environmental heterogeneity. Results The proportion of digitally classified grazed area explained 45% of the variation in field-layer height and 43% of the variation in shrub-cover. Field-layer height was significantly related to vegetation indices. A linear model with three explanatory variables (spectral richness(red), spectral richness(NIR), and shrub-cover) explained 47% of the variation in total within-site species richness. Conclusions High spatial resolution imagery may assist in the monitoring of the processes that follow the cessation of grazing, on the scale of individual grassland sites. Measures of spectral heterogeneity acquired by high spatial resolution imagery can be used in the assessment of total within-site vascular plant species richness in semi-natural grassland vegetation.

AB - Question Can we reliably estimate grazing intensity, indicators of grazing intensity (i.e. field-layer height and shrub-cover), and vascular plant species richness in semi-natural grasslands from high spatial resolution satellite data? Location The Baltic Island of Oland (Sweden). Methods Fieldwork included the on-site description of grazed and ungrazed areas and shrub-cover within 107 semi-natural grassland sites. Field-layer height and vascular plant species richness (total within-site and mean small-scale species richness) were recorded within the sites. Digital classification of QuickBird data was performed to identify grazed and ungrazed areas and shrub-cover. Vegetation indices were generated to analyze the performance of satellite data for estimating field-layer height, and the spectral heterogeneity was used to characterize the within-site environmental heterogeneity. Results The proportion of digitally classified grazed area explained 45% of the variation in field-layer height and 43% of the variation in shrub-cover. Field-layer height was significantly related to vegetation indices. A linear model with three explanatory variables (spectral richness(red), spectral richness(NIR), and shrub-cover) explained 47% of the variation in total within-site species richness. Conclusions High spatial resolution imagery may assist in the monitoring of the processes that follow the cessation of grazing, on the scale of individual grassland sites. Measures of spectral heterogeneity acquired by high spatial resolution imagery can be used in the assessment of total within-site vascular plant species richness in semi-natural grassland vegetation.

KW - Field-layer height

KW - Grazing

KW - Scrub-encroachment

U2 - 10.1111/j.1654-109X.2009.01063.x

DO - 10.1111/j.1654-109X.2009.01063.x

M3 - Article

VL - 13

SP - 221

EP - 233

JO - Applied Vegetation Science

JF - Applied Vegetation Science

SN - 1402-2001

IS - 2

ER -