Nature reclaiming suburbs
Possums are moving into abandoned Christchurch suburbs and a very rare bird has returned to the city as wildlife reacts to the earthquakes.
The growing number of possums is just one of many changes in local wildlife in response to population and landscape changes in eastern Christchurch, including tree saplings already sprouting on empty sites and a potential fall in birds such as pukekos.
Landcare Research pest control scientist Janine Duckworth said possums would prosper in the red zone as humans leave.
"It doesn't surprise me that we are seeing more of them as they do try to avoid people. With fewer dogs in the areas that will allow them to move into places they may not have been able to take advantage of in the past. If they are less disturbed, then more young possums will grow into adults," she said.
Richmond resident Rex Collins found a possum the size of a "fox terrier" on the roof of his home. It is the first he has encountered in 16 years of living in the suburb.
"We woke up in the middle of the night to this loud crashing sound on the roof. We have this problem with squatters next door, so we thought it was someone jumping on our roof. We rang the police and they came pretty quickly. They had a good look around and then they found this huge possum," he said.
"He was about the size of a fox terrier in body size. He had these huge big round eyes about the size of $2 coins."
"A lot of wildlife is coming back into the area. The wildlife is taking over again."
Sub5 security officer Rory Garland, who patrols the red zone for Cera, has also seen many possums on his night patrols.
"I have seen about three or four possums. I saw one just sitting in the middle of the road. In the end it went up a power pole."
A rare Australasian bittern has returned to Christchurch after an absence of about eight years. There are only 700 such bitterns in New Zealand, but bird enthusiasts have spotted about eight in the wetlands near Bexley.
Press photographer and bird enthusiast David Hallett said the bittern was "rarer than most Kiwis" and said it was "amazing" that the bird had returned to Christchurch.
Botanists and bird experts have noticed many wildlife changes in the residential red zone.
Canterbury Museum curator of vertebrate zoology Paul Scofield said landscape changes would impact on bird life. "The floor of the estuary has risen and the river has narrowed and is shallower," he said.
Bird experts believe the loss of salt marshes in the estuary could mean a fall in populations of marsh craics, bitterns and pukekos as they lose their habitat. Salt marshes, a vital habitat for some birds, are dying in the estuary as the land was lowered by the Canterbury earthquakes and they have been flooded. Birds that require salt marsh habitats could move to other areas.
Botanists have observed tree saplings already sprouting on empty sites and fear invasive species will quickly establish themselves in the red zone. Christchurch botanist Colin Meurk has already found birches, yew seedlings, cabbage trees, karamu and pittosporums sprouting on abandoned lots.
Meurk compared the residential red zone to the area around Chernobyl in Russia after the nuclear meltdown.
"In Chernobyl a huge red zone was created in more ways than one. It is said that was one of the biggest wildlife refuges in the world. Wild plants and animals don't care about a bit of radiation. They are all growing a unique eco-system."
"There is international interest in how these systems develop in the face of catastrophic change."
Meurk and bird experts warn that invasive plant species and pests will need to be controlled in the residential red zone.
Bird experts warn that as red-zone residents leave with their domestic cats, predators like ferrets, stoats and weasels will prosper. Scofield said the predators would need to be controlled to protect bird populations.
Meurk said invasive plants will also need to be controlled.
"Plants with windblown seeds like the grey willow are already coming up in residential areas. That could be a problem in terms of building up large quantities of that.
"There needs to be a management plan and monitoring to encourage some species, but discourage and weed out any problem species."
- © Fairfax NZ News
If you were voting for a Christchurch mayor today, who would you vote for?Related story: Dalziel and Parker set for mayoral race