Spontaneous Forest Biodiversity as a Provisioning Ecosystem Service: Nutritional value and secondary metabolites of Four Spontaneous Fodder shrubs from Northeastern Algeria Under Climate Change

Northeastern Algeria is characterized by a remarkable forest biodiversity of spontaneous fodder trees and shrubs that play a key role in maintaining resilient agro-ecosystems. These species represent a strategic provisioning ecosystem service, supplying forage resources critical to sustainable ruminant feeding, particularly in the humid Mediterranean zones where extensive livestock farming predominates and climate change increasingly threatens forage availability. Documenting the nutritional value of this spontaneous forest biodiversity is therefore essential to support adaptive, biodiversity-based livestock strategies. This study aimed to assess the nutritional potential of leaves from four spontaneous fodder shrub species in the Al Ayoun forest (extreme Northeastern Algeria): Pistacia lentiscus, Phillyrea media, Calycotome spinosa, and Quercus suber. Leaf samples were analyzed for their primary chemical composition (dry matter, ash, and crude protein) and their main secondary metabolites (total phenols, total tannins, and condensed tannins).

The results indicated that Calycotome spinosa had the highest crude protein content (16.35% DM), highlighting its potential as a valuable protein source for ruminants. Quercus suber and Calycotome spinosa exhibited phenolic levels compatible with forage use, with total phenols at 33.70 and 25.70 g tannic acid equivalents/kg DM and total tannins at 30.50 and 37.40 g/kg DM, respectively, Coversely Pistacia lentiscus and Phillyrea media exhibited higher phenolic concentrationsm reflecting a more pronounced antioxidative and defensive metabolic response to Mediterranean climate constraints. These contrasting chemical profiles illustrate the nutritional diversity offered by this local forest biodiversity. Overall, the four species, and Calycotome spinosa in particular, confirm the value of this ecosystem service as a sustainable local forage resource, especially for goats, helping to mitigate feed shortages and support climate-adaptive livestock systems in the humid zones of Northeastern Algeria.