The two main threats to the kauila are the damage caused by the introduction of invasive species (1) and the loss of its dry land forest habitat (6).
The introduction of non-native plant species to Hawaii has lead to the drastic alteration of the kauila’s dry land forest habitat. Large amounts of the original forest understory have become covered in a blanket of Kikuyu grass (Pennisetum clandestinum), a plant native to East Africa but an aggressive weed in Hawaii. Kikuyu grass overcrowds and suppresses the seedlings of other species, preventing their growth. The introduction of this grass, originally for the purpose of grazing cattle, has turned what was once a fertile breeding ground for most Hawaiian dry land trees into a 'museum forest' containing only mature specimens, where no saplings have been able to grow for fifty years (7).
Introduced grazing species such as pigs and deer have also threatened the potential of kauila sapling growth, while invasive rat populations, which feed on kauila seeds, have further limited this species’ ability to propagate (1).
The overall kauila population is also under threat from reduced genetic diversity, caused by severe habitat loss and fragmentation due to urban and agricultural development (3). As a result of this human disturbance and the damage caused by invasive species, it has been estimated that over 90 percent of the kauila's primary dry forest habitat has been lost (3). This has led to the kauila population being severely fragmented across a poorer quality habitat, with a reduced growth range and an estimated extent of occurrence less than 20,000 square kilometres (1). On all islands except Kauai, fewer than 50 individuals were observed in 1988, according to the Hawaii Heritage Program (3).