Operationalizing the Patch Concept in Foraging Ecology: A Systematic Review of 133 Species Across EUNIS Habitat Types

Understanding how animals operationally identify and exploit resource patches is central to foraging ecology. The “patch”—a discrete area of resource concentration—is the fundamental unit of individual foraging behavior; however, standardized operational definitions of the criteria for patch identification across taxa, habitats, and biomes are still scarce. Following PRISMA 2020 guidelines, we reviewed 87 empirical studies encompassing 133 species, classifying patch identification methods across eight macro-categories of the European Nature Information System (EUNIS)—a structurally detailed habitat classification that, despite its European origin, we apply here as a general structural template for habitat architecture rather than as a claim of biogeographic universality, given that our dataset also spans non-European taxa and biomes. Patches are operationally identified through two approaches: observational delineation of natural resource structures (e.g., fruiting trees, prey aggregations, vegetation clusters) and experimental manipulation via artificial depletable units. We demonstrate that habitat structural complexity and species trophic preferences jointly govern the operational method by which patches are identified: habitat architecture determines which operational approach is used for patch delineation—observational or experimental—while a four-category Feeding Guild classification (Granivore, Herbivore, Omnivore, Carnivore) reveals that resource discretizability—the capacity to standardize prey into countable, depletable units—operates as the primary species-level predictor of patch identification method selection, an association that remains robust after formally controlling for phylogenetic non-independence and body mass in a mixed-effects model. The resulting framework provides, for the first time, a standardized operational guide for calibrating patch identification methods to habitat type and species trophic preferences and searching behavior across taxa and biomes.