XVI International Botanical Congess

Plant diversity declines with habitat loss and fragmentation. Historical comparisons confirm substantial declines even in specifically reserved areas. Edge habitats foster invasions by exotic competitors and pathogens while diminishing populations of native pollinators and seed dispersers. Fragmented habitats also fail to sustain historical disturbance regimes (e.g., flood, fire), threatening disturbance-dependent species. Scarce predators and abundant edge boosts populations of keystone herbivores like deer who threaten diversity both directly and indirectly. Genetic factors can also threaten demographic viability in both the short term (via inbreeding) and the long term (by reducing genetic diversity). We are struggling to comprehend which species are most at risk and how mechanisms interact.