Dealing With Diversity in Mediterranean Rangelands: NIRS-Based Classification of Pastoral Resources Consumed by Small Ruminants

Mediterranean rangelands provide a substantial part of the annual diet of small ruminants in the extensive livestock systems of southern Europe. Woody vegetation, plant diversity and strong seasonal and structural heterogeneity complicate the estimation of the feeding value of these pastures. Conventional approaches based on botanical composition or herbaceous-layer indicators provide only a partial assessment of feed resource diversity, quality and nutritional role. We propose an alternative approach where we build a classification, based on near-infrared spectroscopy applied to 304 samples representative of the resources selected by sheep and goats in Mediterranean rangelands. Bite types were identified through behavioural observations and sampled across three sites in southern France during spring and autumn over two years. Spectra from dried and ground samples were pretreated and analysed using principal component analysis followed by hierarchical clustering. The resulting clusters separated resources according to plant organs and displayed consistent chemical and structural characteristics. Together, they formed a gradient ranging from protein-rich and highly digestible young organs, to fibre-rich and structurally dense resources. The classification was evaluated through cluster stability analyses, spatio-temporal cross-validations and projection of an independent dataset, complemented by qualitative assessment from farmers and technical advisors. Results revealed stable cluster cores and biologically-meaningful transition zones, particularly for reproductive organs such as grass ears and legume pods. Projection of the independent dataset showed strong overlap with the reference spectral space, supporting transferability beyond the initial sampling conditions. This approach provides an operational framework for integrating pastoral resource diversity into rangeland assessment and feeding management.