Nature, culture and history
Landscape and geology
Kroombit Tops began forming about 215 million years ago when volcanoes erupted and a great circular caldera, or crater, about 40km across collapsed beneath them. About 25 million years later, the area was covered by ocean, covering the volcanic rock with sand beds that were eventually compressed to form sandstone.
Over time, the surrounding countryside eroded away but the tough volcanic rocks capped with sandstone resisted erosion, forming the high plateau of Kroombit Tops. The steep slopes and exposed 100m high sandstone cliffs can be seen along the east and north-east boundaries of the park.
Over millions of years, streams draining to the west and south have carved narrow valleys in the hard volcanic rocks, creating steep-sided gullies and deep gorges where rainforests now grow. The Kroombit, Dry and Callide creeks all flow west into the agricultural Callide Valley while the Munholme and Three Moon creeks flow south into the Burnett River via Cania Dam.
Because Kroombit Tops stands about 900m above surrounding areas to the east, the weather it experiences is much cooler and wetter—a ‘temperate island’ in the subtropics. Temperatures are generally 5 to 10ºC cooler than the surrounding lowlands and can be quite cold in winter, especially at night.
On average, 1800mm of rain falls here each year, whereas nearby Gladstone receives just 1020mm. There is also a marked difference in rainfall across the plateau reflecting differences in elevation, aspect, and the influence of the escarpment. Rainfall is higher in the east and south-east, and lower in the west and north-west. Summer storms with destructive winds are common in the surrounding area, often causing branches to fall from large trees.
Kroombit Tops supports a wide variety of plants—more than 850 species. Three species are found only on this plateau and many are listed as rare or threatened. Vegetation communities change as you move from the south-east to the north-west.
In the wetter south-eastern sandstone country, blackbutt forests dominate, while subtropical rainforests grow around Three Moon and Munholme creeks. Piccabeen palms, brush box, coachwood and white beech, which are normally found further south in temperate rainforests, can be found here.
On the park’s eastern slopes and broad valley floors, open Sydney blue gum forests, pink bloodwood and rough-barked apple trees flourish. Sydney blue gum is another southern species normally found along the coast from south-east Queensland to Batemans Bay in southern New South Wales. It was one of the main trees harvested at Kroombit Tops from 1969 to 1995.
Further west the vegetation changes to drier white mahogany, grey gum and ironbark woodlands. In rocky areas, a stunted form of brush box locally known as 'supplejack' grows. This thin whip-like variety of brush box is very different from the towering subtropical rainforest form.
Dry rainforest grows in fire-resistant gullies on the drier western slopes. Look for the distinctive hoop pines towering above the canopy. Some individuals can grow as tall as 40–50m. In the far west, hoop pine forests merge with a dry bottle tree community.
Kroombit Tops’ varied vegetation and topography shelters diverse wildlife—71 mammal species, 165 bird species, 70 reptile species, 30 amphibians and numerous insect and spider species thrive here. Two species of frog are found nowhere else. Many animals are at the northern or southern limit of their distribution or are genetically distinct populations.
Most of Kroombit Tops’ mammals are difficult to see because they live in caves or are active only at night. However, a sharp eye during a walk or drive at night might surprise you. Rufous bettongs are often seen at night in grassy areas, often feeding beside the road on new plant growth, while swamp wallabies are common in shrubby forest. Kroombit’s caves and trees provide roosting sites for more than 20 species of insectivorous bats. Tree hollows provide nests for short-eared possums (also called bobucks or mountain brushtail possums) and five species of gliders, the most common being the greater glider.
In dry woodlands and open forests, insects and spiders provide food for the mouse-like common dunnart. Herbert’s rock-wallabies bound around the escarpments overlooking the Boyne Valley and rocky outcrops along Kroombit Creek and upper Callide Creek. They are difficult to spot because they are secretive and well camouflaged, but you might see their droppings—cylindrical with a small point at one end—in rocky areas. On cool days if you are quiet, you may see them in the morning or afternoon sunning themselves on north-facing rocks.
The silver-headed antechinus was first discovered at Kroombit and has since been found only at Blackdown and Bulburin.
Large colourful parrots such as Australian king-parrots perch high on dead branches above the forest canopy. Pairs of little lorikeets and flocks of scaly-breasted and rainbow lorikeets screech harshly through the forest. Glossy-black cockatoos feed on forest she-oaks. Wedge-tailed eagles soar above and peregrine falcons nest on escarpment cliffs. At night, powerful owls perch in tall Sydney blue gums, hunting for possums and gliders.
In the rainforest you can often hear the cat-like call of green catbirds and the noisy ‘rustling taffeta’ flight of paradise riflebirds, both at the northern extent of their range. In the canopy the cicadabirds compete with the vocal chorus of cicadas. At night you may hear a sooty owl calling, like the sound of a falling bomb.
On the ground in open woodland you might see squatter pigeons, with their characteristic black and white striped facial pattern. Superb and wompoo fruit-doves favour rainforest habitats.
Among Kroombit Tops’ reptiles are some that usually occur only south of Gympie. Burrowing lizards Saiphos equalis relies on moist forest types such as rainforest and tall open forest; Stephens’ banded snakes are found in both rainforest and dry rocky forest. Diurnal lizards Ctenotus arcanus are dependent on rocky outcrops. These animals are relics from a time when moist forests extended all the way from north-eastern New South Wales to Kroombit Tops.
At the southern limit of their range, black-headed pythons are easily identified by their shiny jet black head and contrasting brown-banded body. They are one of the few snakes that eat venomous snakes.
You may encounter eastern water dragons, lace monitors or red-bellied black snakes sunning themselves by creeks, or small darting lizards on rocky ledges.
Kroombit tinkerfrogs are the park’s most endangered animal. Nowhere else in the world can you hear their unusual call—a series of sharp, metallic ‘tinks’. These small frogs live under rocks and in leaf litter in small areas of gully rainforests along the eastern escarment of Kroombit Tops. Unlike many frogs, they appear not to need surface water to breed, although eggs and tadpoles have never been found in the wild. Instead, it is thought they breed in small underground pools of water, perhaps as small as half a cup.
Kroombit is also home to a second species of endemic frog, the Kroombit treefrog Litoria kroombitensis. If you stop at the Kroombit Creek crossing in spring and summer, turn off your car engine and listen. You might hear male frogs calling to females. Can you distinguish the 'wreeak ik ik' of cascade treefrogs, the slow 'chuck-uk' of tusked frogs or the loud 'wark' of the great barred frogs?
Small, bright green cascade treefrogs are common in Kroombit’s rainforest creeks. They spend much of their life high up in trees, but come down to the rainforest’s middle fern layer to attract mates to the stream in breeding season. Like many frogs and reptiles at Kroombit, this species is usually found further south and the Kroombit population is genetically distinct from populations in south-east Queensland.
Connections over time
Indigenous people have maintained a strong and continuing association with Kroombit Tops for thousands for years. Since gold was discovered in the district around 1870, settlers have mined minerals, grazed sheep and cattle, and harvested timber here.
A road built between 1964 and 1968 opened Kroombit Tops for logging. From 1969 to 1995 hoop pines and hardwoods such as Sydney blue gum, white mahogany and blackbutt were harvested for timber. These trees are now protected in this national park.
Beautiful Betsy WWII Liberator bomber
A WWII Liberator bomber crashed at Kroombit Tops in 1945 and lay undiscovered for nearly 50 years. The area is now managed as a heritage site, and all parts of the wreck are protected.