Plants and Animals

I was interested to read in today’s The Age newspaper that the buffalo hunting season opened in the US yesterday:

The hunt will allow up to 50 of the Plains bison, often called buffalo in North America, to be killed in the three-month season that opens on November 15. A lottery for 24 permits drew nearly 6,200 applicants, including an unsuccessful Montana Gov. Brian Schweitzer.

Sixteen additional permits were reserved for native American tribal members, and 10 went to hunters who had drawn permits for a previous hunt that was cancelled.

Hunters typically eat any bison they kill and sometimes mount the head and horns.

… Facing nationally televised protests and tourist boycotts, the Montana legislature banned bison hunting in 1991.

Regulations forbid game officials from helping, and hunters are all required to attend classes on the rules of the hunt.

At the turn of the 20th century, only 23 bison survived in Yellowstone National Park. The herd now numbers around 4,900.

Which animals can be legally hunted in Australia? I know crocodile hunting is banned in the Northern Territory though 600 are culled every year. There is an annual quota for kangaroos.

Since speaking today with a turtle expert at the local environment protection agency and reading summaries of their autopsy reports I have become more attached to my green bags.

After posting Why Ban the Plastic Bag , a reader of this web-log sent me a long and interesting report titled ‘The Impact of Degradable Plastic Bags in Australia’ published in September 2003 by Melbourne University RMIT, Download file (983 kbs).

I had not realized that there are already a whole range of degradable plastic bags in use and that a significant issue is that they don’t disintegrate as soon as they are thrown away. It seems they are more water proof and freezer safe than degradable.

The Queensland Government’s Environment Protection Agency with Flinders University in South Australia and Seaworld on the Gold Coast were testing the longevity of biodegradable fishing bait bags (pg 61).

The RMIT report indicated that while the research was ongoing, there was already agreement, including with the recreational fishing industry, for the new bait bags at $8.70/kg to be phased in over a two year period and the non-degradable conventional polyethylene bags at $1.50/kg be phased out. Concern that too many plastic bait bags end up in the ocean, and sea turtles eat them believing them to be jellyfish, and die, was driving the move to degradable bags.

The report made reference to the work of Colin Limpus, a turtle expert at the Queensland Environment Protection Agency. According to the report Limpus believed biodegradable plastic bags were a step in the right direction but since they still take six months to degrade in seawater, they are not a complete solution. Limpus was concerned that because the thermoplastic starch is modified to reduce its sensitivity to moisture, that this may prevent digestive enzymes breaking them down, but he accepted that at least in theory, the bags should be digestable and perhaps even nutritious for turtles.

In 2003 Limpus was trying to organize a project to study the breakdown time of biodegradable plastics in the digestive tract of turtles. However, since sea turtles are threatened species he was proposing to use herbivorous fresh water turtles, which are not threatened, in a plastic feeding trial.

I phoned Limpus today to find out where the research was up to.

He indicated that based on the work of a University Honour’s student (being written up) he nolonger supported biodegradable bait bags. He said that the turtles can’t digest them, they may work in landfill, but they are a threat to wildlife.

I asked about plastic bags as a cause of death relative to other threats. Limpus said that autopsy work gave a indication of cause of death and that the relative contribution of plastic bags is available in the environment protection agency’s annual reports at
http://www.epa.qld.gov.au/nature_conservation/wildlife/caring_for_wildlife/marine_strandings . I had a quick look at some of these reports this afternoon and note that in the reports for marine turtles, causes of death include “intestine obstructed with plastic” including bait bags.

Limpus said that turtles ate partially disintegrated plastic from Chinese takeaway containers and icecream containers. He said these types of plastic containers, along with boat strike, were a bigger threat to most of our marine turtles than plastic bags.

Limpus indicated that degradable and non-degradable plastic bags were a particular threat to Leatherback turtles, an endangered oceanic species.

Ten of 33 dead leatherbacks washed ashore between 1979 and 1988 had ingested plastic bags, plastic sheets or monofilament according to this international website http://www.turtles.org/leatherd.htm.

Here’s another photograph from my trip to the Northern Territory of Australia (NT), view image (90KB). This crocodile had just snatched a barramundi for afternoon tea.

There was much talk in the NT about federal Environment Minister Ian Campbell’s decision to not support safari hunting of crocodiles.

Federal government approval is needed for the export of skins and heads. Of the 600 crocodiles culled each year, the NT government wants to let 25 be shot by overseas tourists who would apparently be willing to pay $10,000 for the privilege to shoot a croc – as long as they can take the head and skins home with them.

The Minister has said “No” on the basis that such a plan would send the wrong signal to the world, like that we don’t care about our wildlife.

I have been re-reading ‘At the hand of man: Perils and hope for Africa’s wildlife’ by Raymond Bonner (Alfred A. Knopf, New York 1993). Bonner writes about the early history of WWF and other conservation groups that have their origins in Africa in the 1950s and 1960s. WWF was launched in Tanzania in 1961. The panda symbol was just a symbol, that animal chosen in large part because it reproduced well in black and white. The African Wildlife Leadership Foundation (now known as the African Wildlife Foundation) was also founded in 1961 and by rich Europeans and Americans who were avid big-game hunters. They loved the big animals and wanted them protected, including so they could shot them.

For example, according to Bonner, Russel E. Train was an American tax court judge and avid big-game hunter, founder of the African Wildlife Foundation, first chairman of the White House Council on Environmental Quality, has been head of the Environmental Protection Agency and in the early 1990s was chairman of WWF in the United States.

WWF now supports a Russel E. Train Conservation Program.

I guess the point I am wanting to make, is that at least historically, safari hunting has been synonymous with conservation.

Yesterday I visited popular theme park Dreamworld at Queensland’s Gold Coast. The visit was to celebrate a 10 year old’s birthday. The highlight for her was the Giant Drop.

We also visited Tiger Island and enjoyed a movie about grizzly and polar bears called ‘The Bears’ shown at the Imax theatre. The photography was spectacular and included grizzly bears catching salmon.

Towards the end of the movie we were told that the survival of polar bears was threatened by global warming. We were told that as a consequence of warmer springs, the ice sheets were thinning earlier than usual at the Arctic and as a consequence the seal hunting season was shorter and bears were losing weight.

Polar bears use sea ice as a platform for hunting ringed seals. Late spring is considered a key hunting period when there are usually lots of fat recently weaned seal pups.

The idea that polar bears are withering away as a consequence of global warming gained prominance following the release of a WWF Report in 2002 titled Polar Bears at Risk. The WWF Report relied on a research paper by Stirling et al titled Long-term trends in the population ecology of polar bears in western Hudson Bay in relation to climate change, Artic, Volume 52, Pages 294-306.

This peer reviewed article concludes:

From 1981 through 1998, the condition of adult male and female polar bears has declined significantly in western Hudson Bay, as have natality and the proportion of yearling cubs caught during the open water period that were independent at the time of capture. Over this same period, the breakup of the sea ice on western Hudson Bay has been occurring earlier. There was a significant positive relationship between the time of breakup and the condition of adult females (i.e., the earlier the breakup, the poorer the condition of the bears). The trend toward earlier breakup was also correlated with rising spring air temperatures over the study area from 1950 to 1990. We suggest that the proximate cause of the decline in physical and reproductive parameters of polar bears in western Hudson Bay over the last 19 years has been a trend toward earlier breakup, which has caused the bears to come ashore in progressively poorer condition. The ultimate factor responsible for the earlier breakup in western Hudson Bay appears to be a long-term warming trend in April-June atmospheric temperatures.

While the western Hudson Bay bears appear to be a bit thinner today than they were 20-odd years ago, there has not been a corresponding decline in population numbers. WWF and others acknowledge that the western Hudson Bay population is stable at about 1,200 polar bears.

There are thought to be about 22,000 polar bears worldwide with about 60 percent in Canada. Most bear populations are thought to be stable or increasing in number. Historically hunting has impacted on population numbers and over-harvesting is still considered the main threat to polar bears.

I recently found this site that includes some photographs and a map of the arctic and where to find polar bears,
http://www.polarbearsinternational.org/arctic-map/ .

While it is important to note that western Hudson Bay bears have been losing weight, and that from 1979 to 1998 the trend has been towards an earlier breakup of ice and thus a loss of ‘feeding platforms’ for the resident bears, the evidence is hardly adequate to conclude global warming will result in the extinction of polar bears.

It is interesting to note that the mean time of freeze-up did not change. Furthermore, in eastern Hudson Bay temperatures have been cooling over the same period that they have been warming in the west and the ice has not been breaking up earlier in spring in the east. The total ice cover for Hudson Bay (east and west) did not decline over the study period. Furthermore a distinction should perhaps be made between global warming and climate change?

I started the week exploring the wetlands of Kakadu National Park in Northern Australia. I have ended the week exploring the wetlands of Central New South Wales (South Eastern Australia) with my friend Gill Hogendyk.

Gill, a trained vet, has always had a particular interest in bird watching. After moving to Warren (just north of Dubbo and south of the Macquarie Marshes) in 1990, Gill started taking a particular interest the birds of the Ramsar listed Macquarie Marshes.

Gill is increasingly concerned that the almost exclusive focus on environmental flows and water use by irrigators (her partner grows cotton) has distracted attention from the potential impacts of grazing on wetland environments including in the Macquarie Marshes.

This aerial photo taken earlier this year of the Marshes, shows the dramatic impact of grazing. The fence is the line of demarcation between an overgrazed private property and ungrazed nature reserve. The impact of grazing here is obvious and dramatic.

Over recent years there has been a focus on Australia’s intensive agricultural industries (eg. horticulture, cotton, sugar) and their environmental impacts with most of these industries undertaking environmental audits and developing codes of practice to address issues of community concern.

The grazing industry has had to contend with bans on tree clearing and been excluded from areas including the High Country, but there seems to have been limited interest in promoting best practice and addressing issues of overgrazing.

In the 1940s and 1950s there were restrictions on grazing and burning in the Macquarie Marshes including:

1. Reeds shall not be burned except with the written consent of the district surveyor,
2. Stock shall be excluded from all (reed) regrowth until 3 foot high, and
3. Rookeries (for bird nesting and breeding) will be completely enclosed with a sheep and cattle proof fence.

I understand that there are currently no such conditions on grazing in the Marshes.

It seems incredible that the flood-plain graziers of New South Wales are screaming so loudly for more water and attracting considerable media attention and yet the issue of overgrazing is being ignored by all.

Aerial photograph showing impact of grazing on the Macquarie Marshes.

The website mantained by the local Marsh management committee explains that The Macquarie Marshes is a large non terminal wetland in central west New South Wales and covers approximately 200,000 hectares, 88 percent of which is privately owned. The Macquarie Marshes Nature Reserve makes up the remaining 12 percent and is managed by the NSW National Parks and Wildlife Service.

UPDATE 24TH OCTOBER 2005

I have received some offline emails assuming that the main problem for the marshes is low flow because of Cubbie Station. The Macquarie Marshes are NOT downstream of Cubbie and the Condamine Balonne system.

Rather as detailed here: The Macquarie River is formed by the joining of the Fish and Campbell rivers near Bathurst. The Turon, Cudgegong, Bell, Little and Talbragar rivers join the Macquarie River as it travels north-west. Near the township of Warren, the Macquarie becomes a complex system of effluent creeks, wetlands and floodplains connecting the Macquarie, Barwon and Bogan rivers. The Macquarie Marshes are the wetland and marsh country of this area, consisting of about 40,000 ha of core wetland with up to 220,000 ha inundated during major floods.

The climate of the lower Macquarie River catchment is semi-arid. Rainfall and altitude decrease from east to west, while temperature increases. The marshes are less than 200 metres above sea level and receive approximately 400 mm of rain per year, although flooding occurs in most years due to rainfall in the headwaters of the catchment and occasionally locally (for example, as happened in 1983 and 1995).

Two sections of the marshes are separated by an isthmus and lie on early Tertiary alluvium. The southern section consists of open water linked by anabranches of the river, and contains reed swamps and other emergent vegetation. The northern marshes consist of more prominent braided channels and more extensive reed swamp and river red gum woodland.

I spent yesterday in the Northern Territory’s Kakadu National Park. It was a truly magnificent experience.

I was surprised to learn that in the wet season 75 % of the park becomes covered in water much of it runoff from the Arnhem Land escarpment. I was also surprised to learn that about 75 % of the park is burnt each year.

And I was surprised to see cattle grazing in the park, view image (about 70 Kbs).

When I asked a local about this beast I was told “We would prefer they weren’t here, but these cattle are owned by one of the traditional owners and she lets them come out”.

I understand there were once 300,000 buffalo in the area but this number has been reduced to 1,000.

With the reduced number of buffalo, I am told the water is not so muddy and so there are a few more water birds. I saw a tremendous diversity yesterday including sea eagles,view image (about 70 kbs)and magpie geese.

My favourite was perhaps this comb-crested Jacana, view image (about 70kbs) – also know as a Jesus-birds because their 8 cm long toes enable them to almost walk on water.

Interestingly it is the male jacana that looks after the eggs – usually on a lilly pad. When danger threatens Dad has been know to tuck a few eggs under a wing and run somewhere safe. Mum may mate several times during the one season, leaving a few males each with a clutch of eggs to raise.