Community phylogenetic methods can be used to detect the evolutionary signal of functional traits within communities across a range of environmental conditions. Closely related species may share traits that make them well adapted to difficult habitats, while distantly related species may have evolved to persist in different niches allowing for coexistence. In the face of global anthropogenic change these traits will determine whether species become pervasive invaders or increasingly rare. Here, we examine whether endangered and invasive plant taxa are more distantly or more closely related than we would expect by chance in the Pine Rockland community.
Florida’s Pine Rockland habitat is a model natural system for understanding dispersion of rare and invasive species across a community phylogeny. Pine Rockland habitat is a critically imperiled savannah-like forest found only along the Miami Rock Ridge spanning from Miami, FL to the Florida Keys. Perched at the confluence of North American and Caribbean species ranges, this habitat hosts a unique community of endemic and endangered plant taxa. However, rapid urban and agricultural development in this area has lead to habitat loss, fragmentation, fire suppression and increased incidence of invasive species. We constructed a well-resolved, species level, molecular community phylogeny of the Pine Rockland plant community. We use this phylogeny to determine relative relatedness of invasive and endangered taxa across the community.
Our results indicate that invasive species in the Pine Rockland plant community are less related, while threatened and endangered species are more related than expected by chance. Closely related native species express a specialized suite of traits adapted to the Pine Rockland habitat and are likely to be threatened by fire suppression and fragmentation. Meanwhile, these same anthropogenic changes benefit invasive species that have evolved highly competitive, generalist traits. Identifying phylogenetic signal to invasion and rarity may allow us to predict which species are likely to progress from exotic to invasive and endemic to endangered.