Found only in northern Australia, hummock savannas are distinguished by a ground layer of slow-growing, domed hummock grasses interspersed with bare ground and some trees and shrubs. These habitats are less strongly seasonal than other savannas, but still with winter droughts and summer rains, and many plant adaptations to seasonal drought. Recurring fires are an important factor promoting patchiness of vegetation, but post-fire recovery is slower than other savanna ecosystems. Rocky coarse-textured substrates are low in nutrients. Foodwebs are correspondingly simple, with large numbers of invertebrates and low numbers of mammalian herbivores and vertebrate predators.