Mammaldominated

Mammaldominated is an informal descriptor used in ecology and geography to denote ecosystems in which mammals are the most influential vertebrate group in terms of biomass, population density, or ecological roles such as herbivory and predation. It is not a formal taxonomic category, and other groups such as birds, reptiles, and invertebrates can be present and ecologically important, but mammals exert outsized influence on the structure and processes of the system.

Applications of the term typically rely on qualitative judgment but may be supported by quantitative indicators such as unusually high mammalian biomass relative to other vertebrate groups, prominent top-down control by large carnivores, or the central role of mammals in seed dispersal, nutrient cycling, or disturbance regimes (grazing, trampling). The concept is often used together with other descriptors like herbivore-dominated or predator-driven to describe how trophic interactions shape communities.

Examples are context dependent and can vary by biome. In many savannas and tropical forests, megafauna and other large mammals influence vegetation structure, soil properties, and ecosystem dynamics. In Arctic, boreal, and temperate regions, large herbivores and their predators can similarly drive ecological patterns. In theory, the term highlights the functional importance of mammals rather than suggesting exclusivity.

Limitations: as an informal descriptor, mammaldominated lacks a universal metric. Researchers may differ in whether and how they quantify dominance, and scale and seasonality can affect conclusions. Human activity can also alter mammal influence by changing species composition, abundance, and interactions.