Aim: Mammalian carnivores are among the best studied groups in terms of evolutionary history. However, the effects of species interactions in shaping community assemblages remain poorly understood. We hypothesize that indirect interactions via ecological trait filtering play a key role in structuring carnivoran assemblages, mediate coexistence, and thus should show high functional diversity in space and time at continental scales.

Location: Americas.

Taxon: Mammalian carnivores (Mammalia: Carnivora).

Methods: We followed a macroecological perspective via ecological networks analyses for indirect interactions, and assessed the underlying functional diversity (FD) across space and from the Last Interglacial to the present in the Americas. We analyzed the potential distributions and six ecological traits of 88 species to establish possible mechanisms that enables species to coexist and the underlying diversity patterns. We compared the empirical results with two null models, and two sensitivity analyses.

Results: Co-occurring carnivore species presented ecological segregation driven mainly by a size ratio (S _R) relationship, called here the body-size spatial anti-clustering effect. The underlying FD patterns showed low redundancy towards the tropics and the poles during the times evaluated. However, during the LGM, shifts occurred primarily at high latitudes in North America. This shift affected the S _R relationship and therefore changed functional diversity patterns. These local-to-continental interactions mediated by the S _R are significant from an ecological and biogeographic perspective, suggesting a robust and consistent trend in which carnivore species of similar size have a lower probability of occupying the same area unless they differentiate in other ecological trait spaces.

Main conclusions: The S _R relationship is potentially a primary mechanism limiting carnivore coexistence, reflecting functional filtering. The S _R tends to be conservative across different ecological trait groups and through time and space. We propose that the body-size spatial anti-clustering effect can directly measure species' coexistence and mediate FD patterns in the Americas.

The species-space matrix (i.e, binary matrix, 0/absence, and 1/present) for each of the three time periods considered in this study (i.e., Data__Current_space.csv, Data__LGM_space.csv, and Data__LIG_space.csv). The first column of each database represents each spatial unit, and the first row represents the species. For the species' point-occurrence data matrix (i.e., Data_localities.csv), the first column represents the species, and the first row indicates the spatial unit.

Ecological characteristics and codification used in the Data_Traits. csv for assessing carnivore assemblages. Trait codification in the database was present (1), absent (0).

Body mass (Bm): this ecological trait provides considerable information about the ecology and life history of species and has proven informative for most of the fundamental characteristics of an organism in terms of adaptation to their environment and interaction with other species. The variability in body mass is a good predictor of the ecological niche of species, therefore is considered a proxy of functional diversity due to its relationship with ecosystem functioning. Female mass (Fm); male mass (Mm); minimum mass (Minm); maximum mass (Maxm)

Locomotor behavior (LB): this ecological trait provides information about the locomotive adaptations to different substrate, indicating a relationship between the species and their environment. This is important because it reflects details of their feeding strategy. Likewise, this trait could reveal much more about carnivore species history life, preferred habitat, foraging behavior, and escape strategy. One species may have one or more locomotor behavior, Aquatic (Ac); Terrestrial (T); Arboricolal (Ar); Scansorial (Sc); Fossorial (F).

Social organization (SO): this ecological trait represents the mean number of individuals of the species present during most of the year outside of the breeding season. Group size is considered as an anti-predator response, since larger groups reduce the risk of predation per capita, by increasing collective vigilance and predator detection, or by collective defense. Groups (G); Solitary (S); Group size (GS).

Activity pattern (AP): this ecological trait represents the active period where the species is most active during a 24 h cycle. The active period is related to resource use and is influenced by physiological constraints. Diurnal (D), Nocturnal (N); Catameral (C).

Trophic realm (TR): this trait represents the main indicator of resources used and covers several dietary attributes that reflect amplitude of species diet. carnivore (TrC); herbivores (TrHe); Omnivores (TrOm).

Trophic guild (TG): this ecological trait represents the main feeding specialization of the carnivoran species. It describes the different feeding types and allows to distinguish species more precisely. Carnivore big (TgCb); carnivore medium (TgCm); carnivore small (TgCs); carrion (Car); piscivores (TgPis); invertebrates (TgIn); frugivores (TgF).

Continental presence (CP): North America (NA); South America (SA); Central America (CA).

Period (P): Last Glacial Maximum (LGM); Last Interglacial (LIG); Current (C)