Fogg Dam Management

NT Parks & Wildlife management of Fogg Dam

Fogg Dam is managed by the Northern Territory Parks and Wildlife Department which are also responsible for Malaka Swamp, Lambells Lagoon, Djukbinj, Black Jungle, Hotham Conservation Reserve, Leaning Tree Lagoon and Harrisons Dam.  This represents around 72,0000 hectares in reserves and untold kilometres of travel to get around them all.

There are only 4 permanent rangers to do this.

Key aspects of management in these reserves include managing crocodiles, fire, weeds and invasive animals, damage due to storms, visitor safety and experience, infrastructure and poaching.  They have their hands full.

Crocodile Management

Estuarine Crocodiles are apex predators and frequently roam into the area looking to make a snack of any unfortunate creature that gets too close.

The rangers regularly set crocodile traps and do airboat surveys to keep a handle on this. At the time of writing, there is believed to be 2 salties in Fogg Dam. Both are near the 2.5 metre size.  One can be found in the pond in front of Pandanus Lookout whilst the other tends to loiter near the waterlily walk.

In addition to the saltwater crocodiles, there are also plenty of harmless fresh water crocodiles in Fogg Dam.  Typically there are around 6 to 10 at any one time with a couple of local celebrities (Freddie & Toothless) often being seen.  Although freshwater crocodiles regularly get caught in the traps, they are generally released back into the dam due to their harmless nature.  They also keep the tourist happy.

Maintaining Open Water

One of the lesser-known tasks for the rangers is actually maintaining the open water component of Fogg Dam. Annual siltation, sedimentation and organic growth and deposition mean that there is an ever-present trend for the dam to transition into dry land.

This is known as succession and is a natural phenomenon, however, given that humans have destroyed many natural wetlands perhaps it is about time we began to maintain some.  To stem the tide on this the rangers employ a floating weed harvester.

The WEED HARVESTER literally cuts and pushes floating mats of vegetation around the dam to a point where it can be pulled from the dam and burned.  A relentless task and prone to hiccups.

Fire Management

Another major task for the rangers is the management of fire.  The various ecosystems found in and around Fogg Dam make fire a serious concern.  Each various ecosystem (Floodplains, Grasslands, Woodlands and Monsoon forests) requires its own fire management strategy.  Sadly with wildfires and plenty of arsonists operating, often the optimal outcome is not achieved.

Under natural conditions, most of the landscape should not be burned more than every 3 years.  Some, such as the monsoonal forest areas are not set up to handle fires and thus require a longer interval between burns.

Frequent fires, late-season fires, and burning in places such as monsoon forests result in a decline in biodiversity.  Death of mature trees with limited or no recruitment of new trees is a clear example of this.

In 2020, 39.4 % of the total land area managed by the rangers was burned. Of this 63% was due to fires lit by arsonists or by accident.  Lightening strike (wild fire) accounted for 1 fire out of 15.

Common offenders included hunters looking to clear land for access and to retrieve their hunting dogs or disgruntled people looking to cause trouble for the rangers.  All in all, a sad lot of humans.

The sensible fire season ends for Fogg Dam and the area in the first week of July.  Any fires after that should be reported to authorities.

Feral Plants

Major plant pests at Fogg Dam include Mimosa pigra, Olive hymenachne and Gamba grass.  Combating these invasive pests is a very costly task.  For the most part, aerial spraying using a helicopter is the primary method to combat these weeds.  This is due to the location, access, scale and presence of crocodiles in the water.

As with anything involving helicopters, this is a costly exercise at around $600 an hour

Aerial spraying also introduces plenty of controversy as the potential for impact on non-target species is high and broader ecosystem impacts uncertain.

Biological control of things such as mimosa has proved successful in part however it is still a significant pest.

Gamba grass has spread rapidly in recent years in Top End and poses a significant threat to all terrestrial ecosystems.  Having a combustion temperature around 10 times hotter than native grasses means that when a gamba fire occurs there is widespread destruction of everything.  Much public pressure is being applied on the NT Government to target this pest.

Some native plants are also causing concern.

Sesbania is a classic example of a plant being out of balance with its environment.  In recent times Sesbania has established large mono cultures in previously diverse areas around Fogg Dam.  This has led to a decrease in amenity value of the area as well as biological value.

Being a native any control methods become political as much as environmental as the rangers battle to keep Fogg Dam alive.

FERAL ANIMALS

Feral buffalo and pigs are of most concern at Fogg Dam.  Both are rife in Northern Australia and especially along the floodplains.  In addition, there is periodic invasion by cattle owned by wealthy nearby pastoralists.  These ‘Barons’ loathe retrieving the animals once they ‘wander’ into the conservation area as it is a ‘free feed’.

Damage caused by these beasts continues to be felt.  Principle impacts include: erosion, decreased recruitment of new plants/ trees, spreading the seeds of weed species and decimation of native flora (such as the native water chestnut).  All of these have direct consequences for native fauna and flora.

Funding

Management of Fogg Dam is financed in a large part by the NT Government.  Sadly the NT Government is perpetually broke and looking to slim down expenditure in the Parks.  Some of the key features such as the weed harvester have actually been supplied to the parks office via the actions of volunteers and Not For Profits.  Principle amongst these is the Friends of Fogg Dam group.

Near Fogg Dam

Nearby, only a few km down the road is the small village of Middle Point.  More accurately it comprises of Middle Point junior school and a research station where CSIRO, University of Sydney and Charles Darwin undertake environmental studies in the area.  Originally this was the base of CSIRO operations for the rice team but has since morphed into a broader environmental and agriculture research station.

The research groups have contributed greatly to knowledge of the ecosystems of the area with some ground breaking results showing the migratory behaviour of snakes in response to the movement of their favourite prey item (dusky rats). This was the first instance where snakes have been found to migrate for their tucker ! In turn it was found that the rats don’t do well during large flood events and atypical storms such as Cyclone Tracey.  Numbers crashed and subsequently this was felt throughout the food chain.

Invasive animals have and continue to be a focus of study.  In particular the implications of invasive animals such as cane toads and water buffalo are of prime interest. The first because if it’s widespread almost certain death outcome for all animals which think a frog looks tasty and the second for the widespread damage that buffalo do to the physical and chemical attributes of the wetlands of the Top End and also to increase the positive financial gains that come from farming Buffalo.

Useful Links

Friends Of Fogg Dam

Weather

Our tour that goes to Fogg Dam

NT Research Farms