Koala ecology and management is subject to debate and opposing views. Research indicates the density of koala populations is related to foliage nutrient content. The presence of plant chemical defences called diformyl-phloroglucinols affect koala diet. Habitat loss, dogs and cars are the greatest potential threat to koalas. Chlamydia, a bacterial disease once thought to threaten the survival of the species, is not a significant threat, although it may act as a population control measure.