31 October 2019
There are two types of ecosanctuaries; those which are fenced, such as our Maunga, and those which are not, but which rely on bait stations to provide a level of protection to enable native and endemic species to breed. I have been involved with Maungatautari in a small way since its inception, and recently have been helping with the Mangatutu Project which relies on poison in bait stations to control ship rats, the principal predator of bush birds. This has given me an insight into how both systems work, and their strengths and possible weaknesses. Please note that these are my personal observations only, and so contain my biases and prejudices.
The headwater area of the Mangatutu Stream lying to the South of Maungatautari, has been the site of an intensive bait stationing project for the best part of thirty years. During this time kokako, the keynote species, have increased to the stage where birds can be removed for relocation without detrimental effects on the overall population. Of course other species have ridden on the kokako's tail feathers and all of the recently occurring species in this area are in very good numbers. Our kokako and pitoitoi were sourced from Mangatutu.
For twenty years the Mangatutu Project poisoning effort has been run by the Howick Tramping Club with help from the Pukekohe Tramping Club. When I had the opportunity to help out recently I jumped at it, principally as a way to say "Kia Ora" for our beautiful birds. Like all voluntary outfits, the tramping clubs are suffering from advancing age, slow recruitment, and older members falling off the perch and so they welcomed a broken-down 68 year old with open arms.
The dedication of this bunch is amazing! They meet for the first weekend every month from August until January at Rangitoto Station checking hundreds of bait stations and replenishing them as needed. The weather is invariably bad, the tracks muddy and the packs heavy. I have been known to disparage Aucklanders, but I would defend these people to the death. Richard, 82, has only recently taken on doing the road bait stations on doctor’s orders, but spends days standing at a table packing bait into plastic bags. Robyn, 78, did 6 hours on her own trudging around a muddy track replenishing stations. These are just two examples of the mettle of this group.
Now for my opinions.
Fenced sanctuaries are fiendishly expensive to set up. Open sanctuaries require a more modest input at the start.
Once fenced sanctuaries are cleared of pests, toxins are used only in small amounts when rare breaches occur. On the other hand open sanctuaries need annual use of toxins for as long as the project runs due to invasion from the sides.
Fenced sanctuaries need few dedicated people to maintain the integrity of the fence. Open sanctuaries require large numbers of volunteers who have their own lives to lead, and rely on their dedication to keep the project viable.
Fenced sanctuaries protect the entire ecosystem inside the wire, invertebrates, plants, amphibians, reptiles and birds. Open sanctuaries protect key species of birds, with some relief for other life forms.
The Mangatutu catchment has not only rats, but the whole raft of mammalian pest species. The bush is badly eaten-out with Horopito and Crown fern, both unpalatable to deer and goats, the most common species. In many places it is possible to look under the canopy for 75 meters or so. The forest floor is also rooted up in many places by pigs. I do not regard the deer numbers to be very high, but once in this state it only takes a few deer moving through to maintain it in this impoverished state. Pigs have a reproductive rate rabbits would be proud of, and often go through eruptive phases followed by crashes when food runs out. This is very damaging to the forest floor and invertebrates.
I have observed the vegetation on Maungatautari since before the fence went in when the bush was identical to Mangatutu. Since the fence was completed and mammals removed (except for some pesky mice) the recovery of the vegetation has been incredible. Ice cream species (very palatable} such as Kanono, are now everywhere and flourishing. Invertebrate numbers are so high that our kiwi grow much quicker than elsewhere. Dead boughs from possum damage have disappeared and the bush is alive and vibrant. The Korowai is back on Maungatautari's broad shoulders!
Dear reader you will by now know which sanctuary I prefer, but I love the other as well. Fenced sanctuaries are rare but the unfenced variety are popping up everywhere, a great credit to the legions of volunteers who keep these projects viable. Some are only a few hectares in size, others several thousands, but they all a vital role in preserving Aotearoa’s amazing diversity.
In finishing I share my favourite quote in case we forget how special our endemic species are;
"If you want to see what life on another planet could look like, go to New Zealand"