Data from: The utility of normalized difference vegetation index for predicting African buffalo forage quality

Many studies of mammalian herbivores have employed remotely sensed vegetation greenness, in the form of Normalized Difference Vegetation Index (NDVI) as a proxy for forage quality. The assumption that reflected greenness represents forage quality often goes untested, and limited data exist on the relationships between remotely sensed and traditional forage nutrient indicators. We provide the first study connecting NDVI and forage nutrient indicators within a free-ranging African herbivore ecosystem. We examined the relationships between fecal nutrient levels (nitrogen and phosphorus), forage nutrient levels, body condition, and NDVI for African buffalo (Syncerus caffer) in a South African savanna ecosystem over a 2-year period (2001 and 2002). We used an information-theoretic approach to rank models of fecal nitrogen (Nf) and phosphorus (Pf) as functions of geology, season, and NDVI in each year separately. For each year, the highest ranked models for Nf accounted for 61% and 65% of the observed variance, and these models included geology, season, and NDVI. The top-ranked model for Pf in 2001, although capturing 54% of the variability, did not include NDVI. In 2002, we could not identify a top ranking model for phosphorus (i.e., all models were within 2 AICc of each other). Body condition was most highly correlated (equation image; P ≤ 0.001) with NDVI at a 1 month time lag and with Nf at a 3 months time lag (equation image; P ≤ 0.001), but was not significantly correlated with Pf. Our findings suggest that NDVI can be used to index nitrogen content of forage and is correlated with improved body condition in African buffalo. Thus, NDVI provides a useful means to assess forage quality where crude protein is a limiting resource. We found that NDVI accounted for more than a seasonal effect, and in a system where standing biomass may be high but of low quality, understanding available nutrients is useful for management.NP_01-02_KNPThese data comprise the mean fecal Nitrogen and Phosphorous values, for herds sampled in Kruger National Park, South Africa, in 2001 and 2002. These data were used in analyses in Ryan, S.J., Cross, P.C., Winnie, J, Jr, Hay, C., Bowers, J., Getz, W.M. 2012. The utility of NDVI for predicting African buffalo forage quality. Journal of Wildlife Management. 76(7):1499-1508Buffalo Body Condition DataThese data comprise African buffalo body condition scores created from video files in Kruger National park in 2001-2002; a subset of these data were used in Ryan et al, 2012, as described in methods therein. This dataset contains 5,327 observations. DO NOT open this file in Excel, as the age ranges will be read incorrectly.ConditionData.csvVegetation and fecal indicators of Nitrogen and PhosphorousThese vegetation and fecal data were used to describe the relationship between fecal and vegetation Nitrogen (N) and Phosphorous (P) content, in 2002-2003 in Kruger National Park, as described in Ryan et al, 2012veg_fecal.cs