The synergy of patterns vs. processes at a community level: a successful mechanism underlying subtropical native forests along the urban riparian zone

Abstract Riparian zone possesses ecological position with biota differing from aquatic body and terrestrial lands, and plant-animal coevolution may be the main factor for the framework of riparian vegetation. In the current study, the riparian plant community patterns along the subtropical mountainous riparian belts of Chongqing, China, was proposed to be regulated by co-evolving with the avifauna through propagule-dispersal process. The results show that: 1) the forests’ species composition and vertical layers are dominated by native catkins of Moraceae species with adapting traits of small and numerous propagules to frugivorous bird species, revealing an evolutionary trend different from the one in the terrestrial plant climax communities in the subtropics, and which forms a biological base for the plant-bird co-evolution; 2) there are significant associations of plant-bird species clusters, i.e., four plant-bird co-evolution groups (PBs) were divided out according to the plant species’ dominance and growth form relating to the fruit-dispersing birds’ abundance; 3) the correlation intensity within PB ranks as PBⅠ>Ⅱ>Ⅳ>Ⅲ, indicating the PBⅠis the leading type of co-evolution mainly shaped by the dominant plant species; 4) the PB correlation may be a key node between patterns vs. process of a riparian ecosystem responsible for the native vegetation, or even the ecosystem health. The results theoretically contribute new evidence to plant-animal co-evolution interpreting the forests’ characters in riparian environments, and urban planner and managers may simulate the native forests for restoring a more stable riparian biota, a better functioning ecosystem in subtropical zone.