Friday, April 29, 2011

Mexican Poppy Update

Mexican Poppy flower

After our posting on this subject in February, Mexican Poppy's have again reared their ugly heads in Alice Springs, this time in Laura Creek, south of Pine Gap. After rain at the beginning of April, germinating poppies were located by Land for Wildlife member Rod Cramer.

The Mexican Poppy (Argemone ochroleuca) is a native of Mexico and Central America. It was first recorded in Australia in 1845. A declared Class B weed in the Northern Territory, it mainly occurs in sandy river and creek beds, but has also been found in other disturbed sites in and around Alice Springs and the McDonnell Ranges.

 The poppy's only grow from seed, most of which falls at the base of the parent plant when ripe. It is easily spread downstream during floods but can be spread to other catchments, gardens and properties through the transportation of contaminated river sand. Infestations of the weed in remote areas such as along the Finke River probably result from the spread of sand and seed, inadvertently transported from infected areas on vehicles, people and camping equipment. 

 Small infestations of Mexican Poppy are easily controlled by hand pulling the plants. It is important to remove plants before they seed. The plants are an annual species that germinate after sufficient rain and seeds can remain viable in the soil for up to seven years. Control therefore needs to be repeated until the seed bank is depleted.
The seed pod of Mexican Poppy

If your property is free of Mexican Poppy, you can help keep it that way by not using river sand from known infected areas (such as the Todd River) when landscaping or during other remediation work. Use sand from another area, or sand that has been treated to remove unwanted biological contaminants.

The Northern Territory Government has excellent information on this and other weeds on their website: If you notice outbreaks of this weed or any other weed or plant you can't identify that seems unusual, let us know about it. New weeds are appearing all the time and you can help stop their spread by letting the right people know.

Thursday, April 21, 2011

Dog Trapping to Start Soon...

Shiny and new - the dog traps all ready to start removing dangerous ferals from member properties.
Land for Wildlife's threat mitigation project for the Black-footed Rock Wallaby is set to start on four properties over the next few weeks. Funded by a Territory NRM Local Action Grant, the project is primarily aimed at removing feral dogs from potential wallaby habitat in the hope that the little wallabies can spread out and have one less predator to worry about.

We have some great habitat lined up for the trapping project, so we're hoping to be removing problem dogs and seeing more wallabies on members' properties in the future. In other projects of a similar nature elsewhere in Australia, marsupial populations have increased significantly in the wake of feral predator removal so we are tentatively optimistic that our project might have a similar outcome.

Any dogs caught will be processed through the standard ASTC dog trapping program and will be turned in to the RSPCA kennel to await an owner or be put down.

The plan is for three weeks of intensive trapping and monitoring on the selected properties. After this the traps can remain in the control of the property owners if there is a continued threat of feral dogs moving into the area. Then the traps will be available for loan in much the same way as our dove trap loan scheme. If there are member properties out there in need of dog trapping and the traps are sitting here unused then they will be available for loan.

We'll let you know how the project is going after the first three weeks of trapping.

Monday, April 18, 2011

Ooldea Dunnart found on Land for Wildlife Property in Alice Springs

Ooldea Dunnart, Sminthopsis ooldea, from a Land for Wildlife property on Heath Road.
The large population of house mice currently in Alice Springs has been well documented of late, with supermarkets and hardware stores doing a roaring trade in mouse traps. I've seen several different models for sale lately, as well as hearing stories of home made devices that work just as well.

All these different inventions have one thing in common. They're extremely good at catching small mammals - and they don't distinguish between pests like the house mice and creatures you might find more interesting. They'll catch anything that's small and furry and attracted to the bait that's placed in the trap.

Central Australia has a diversity of small, mouse sized mammals. Some are rodents (rats and mice) and others are marsupials and many are attracted to the same baits you might use in a mouse trap. In fact, when carrying out fauna surveys in the field, we trap small mammals by using a bait of peanut butter and oats, the scent from the peanut butter often proving irresistible for any critters passing by the traps.

Many of the native mammals don't live in as close a relationship with people as the house mouse. It would certainly be unusual to see any in your kitchen cupboards, let alone catch one! However, in exceptional times, such as that we're experiencing after such a high rainfall, native mammal populations increase and they are forced into areas they would not normally frequent. This may mean that their distributions expand (such as in the case of the Long Haired Rats you've already heard about) or it may cause animals that generally keep to themselves to pop up unexpectedly close to humans.

In the last two weeks, two specimens of small marsupial dunnarts have been handed into us. Both were found in peoples' backyards here in Alice Springs. One was located dead in a driveway in Eastside and another was found by Uwe Path at Pathdorf Bed & Breakfast on Heath Road. Uwe discovered his specimen in a mouse trap, having been attracted to the bait set for mice. Luckily, Uwe had a close look at the animal and realised what it was.
Ooldea Dunnart, Sminthopsis ooldea.

There are several species of dunnart in central Australia, they're difficult to distinguish from one another and most are roughly the same size and colour of a mouse. Uwe noticed some differences, however. Particularly the sharp, pointed nose and large ears of the animal and the sharp, pointed teeth made for a mainly carnivorous diet. You can see these features in the photographs.

We're yet to positively identify Uwe's animal, but it's most likely to be an Ooldea Dunnart. Unfortunately it was killed by the trap. Nonetheless, it's an interesting record from a suburban garden. So check those traps carefully! Not everything that looks like a mouse is a mouse.

If you find any unusual mammals around your property we'd love to hear about it. In this great season we're having, all sorts of mammals are showing up that haven't been seen for some time. If you can preserve the specimen in a snap-lock bag and put it in your freezer it will keep until it can be identified. If you have a camera, try to get some good clear photographs in natural sunlight. Ideally, a profile and front-on shot of the head, a full body shot with something in the frame for scale and a good clear photograph of the soles of the feet can help to clinch the identification of some of the trickier species.

Thursday, April 7, 2011

Fear Not! It's a Plague Rat, not a rat plague.

Media coverage has been all over the supposed rat plague besieging Alice Springs this week. This is all very exciting but has twisted the story a bit and missed the most interesting parts.

Firstly, these are not feral rats, but native rats. Feral rats are very rarely recorded in Alice Springs and are usually the result of deliberate releases of unwanted pets - these animals don't last long in our climate. Secondly, a grand total of 6 animals have so far been identified which hardly constitutes a plague. It seems that we will certainly see more of these animals around town in the next few weeks, but we are a long way from surrendering the town and calling in The Pied Piper.

The animal that has everyone talking is the Long-haired Rat, Rattus villosissimus. This animal is known colloquially as a plague rat because of its ability to reproduce very rapidly during good seasons and spread out across the country to areas where it may not have been seen for decades. A female Long-haired Rat can produce 12 young every three weeks in good conditions.

This animal is usually rare, even in its core range on the cracking black soil plains of the Barkly Tablelands and further south in cracking soils along the eastern fringes of the Simpson Desert, and probably also in parts of the Tanami Desert. Its appearance is often followed by population increases in the Letter-winged Kite, Elanus scriptus, and Inland Taipan, Oxyuranus microlepidotus. Both of these animals share a similar pattern of population boom and bust and maintain core populations in similar areas to the Long-haired Rat. Letter-winged Kites and Inland Taipans both have adaptations to make the Long-haired Rat the main part of their diet.

The Letter-winged Kite is the only predominantly nocturnal hunter among the other raptor species in its family. It has large dark markings around its eyes which aid its vision on moonless desert nights in search of the nocturnal Long-haired Rat. These markings even give the Letter-winged Kite a vaguely owl-like aspect even though it is not closely related to the actual owls (Strigidae).

The Inland Taipan is perhaps best known as having the most toxic venom of any terrestrial snake on earth. It may have evolved this in response to the Long-haired Rat's impressive choppers. Anyone who has ever had to handle a Long-haired Rat, and been bitten, will testify to their gnawing ability. Snakes (and most reptiles) have a slower metabolism than mammals and can be very susceptible to infection of any open wounds as they take longer to heal. The typical elapid (front-fanged snakes) technique of striking and constricting their prey might be disadvantageous if the snake was spending most of its time hunting Long-haired Rats. The inevitable gnawing suffered while waiting for venom and asphyxiation to take effect would take a devastating toll. So the Inland Taipan has developed a unique strike and retreat method of hunting. To make this technique viable it has had to evolve a venom so potent that its prey will be immediately immobilised. The snake can then observe the prey from nearby until it is quite sure it is safe to approach without fear of being chomped by those great teeth.

So what we are witnessing here in Alice Springs is the very pulsing of the boom and bust natural economy of our deserts in action. These rats have not been seen in Alice Springs for around 25 years and they will probably not be around for long. As sure as the rats are breeding up and spreading, so are the kites and the taipans. While it is unlikely that Inland Taipans would make it as far as Alice Springs, people down around Oodnadatta and Coober Pedy might start seeing a few more as the season progresses. The Inland Taipan's other trick is its ability to remain active right through the cold desert winter. It manages this through some impressive adaptations in its vascular system, but that is a story for another time.

The Letter-winged Kites will almost certainly be seen around The Centre in due course. As the rats make their way here, the kites will follow.

Soon enough, the rat population will dwindle, the taipans will retreat back into deep cracks in the earth, and the kites will return to their stronghold colonies out in the desert. We may not see any of these animals in such numbers again for another 25 years or more.

Friday, April 1, 2011

Ironwood Germination - A Once in a Lifetime Event

Ironwood (Acacia estrophiolata) is a common tree of rural blocks in Alice Springs, and many large, remnant trees also exist in urban parks and even backyards in the town. These trees are very slow growing, with large individuals perhaps reaching an age of several hundred years. They also require very specific climatic conditions for the germination of seeds to occur.
The exact requirements are still poorly understood, but germination seems to require periods of above average rainfall, with this rainfall occurring across both Winter and Summer seasons. Typically in central Australia, rainfall events are concentrated in the warm months, with little or no rain occurring in the cool part of the year. There may also be specific temperature requirements as well. This being the case, the germination of seedlings of Ironwood is a rarely observed event.

Ironwood seedling

Seedling root structure

It is exciting then to report that during a recent property assessment in the Ilparpa area, we were able to identify ironwood seedlings that were approximately 6 months of age. These have germinated in response to the exceptional climatic conditions throughout central Australia in the past 12-18 months. Ironwoods are slow growing and can reproduce by suckering from the roots, so often, small plants of seedling size are in fact much older plants. Some individuals that germinated during the last recorded event in 1973-74 may still be less than 1/2m tall!

The key to identifying a young ironwood seedling is by examining the root system. You can see from the photographs the small tap root quickly branching in to fine lateral roots in the seedling. An older plant will have a much deeper tap root and you may find it difficult to find any lateral roots close to the surface. Of course, plants that are suckering will be attached to the much larger root of a parent tree.
If you think you have new Ironwood seedling on your property, we'd love to know about it. Perhaps carefully dig around the roots to see if it looks similar to the photographs. Take a picture of your own, and send them into us to record this rare and special event.