Together forever? Hummingbird-plant relationships in the face of climate warming

Abstract

Identifying species’ extinction risks and understanding their ecological associations are considered critical steps for achieving long-term conservation of biodiversity in the face of global changes. We evaluated the potential impact of global climate change (GCC) on the co-distribution patterns of 12 Mexican endemic hummingbirds and 118 plants they used as nectar resources. Using ecological niche modeling, we estimated the species’ potential distribution areas and their degree of range overlap at present and under future scenarios (2040’s–2080’s). We then performed temporal beta diversity analyses (based on Sorensen’s index) to assess changes in community assembly over time. To determine the potential impacts of GCC on the organization of hummingbird-plant relationships, we calculated niche overlap and network size metrics. Our results showed that even if we assume that species can disperse to novel habitat areas, at least 46.2% of hummingbirds and 45.8% of plant species will face range reductions due to changes in their climate-suitability areas, which will in turn result in an increased mismatch of their co-distribution patterns. Additionally, temporal beta analyses suggested species turnover between the present and future, as well as changes in niche size and overlap for hummingbird-plant co-occurrence networks. These changes could lead to the formation of novel assemblages through species reshuffling, with a tendency to the specialization of networks. These results emphasize that we should not expect uniform or matched responses among species and regions into the future. Therefore, analyses of species’ co-occurrence are needed to accomplish the long-term protection of important ecosystem services such as pollination.