Last week we ran a special trip for Southwestland locals to promote awareness of the wetland conservation efforts conducted by the Department of Conservation throughout the region. We paddled on a new lake – which was exciting for me! And listened to a very knowledgeable Jim Little from DOC speak about the Kahikatea wetlands on the North End of Lake Wahapo.
Lake Wahapo is situated north of Franz Josef, and the next lake to the north from Lake Mapourika (our usual venue). As you drive past the lake you can’t help but notice it’s water is different color to most others in the region – and the wetlands forest has an eerie look.
It turns out the Lake and it’s surrounding forest is not healthy at all. Lake Wahapo feeds the Zalas river which has been dammed for a power station lower down. As a result there is a build up of sediment in the water which is causing the lake to contain less oxygen, and is negatively impacting the surrounding Kahikatea wetlands forest.
This is not the only issue which is affecting the Lake. There is farmland behind the wetlands with a fence dividing the two regions. Cattle can find a way around the electric fence barrier and their ‘droppings’ can actually change the soil balance allowing plants to grow that aren’t supposed to be there and eventually ends up in the water. Deer come along to graze on the wetlands as well. All of these issues keep the DOC team that work to restore this area pretty busy!
Jim pointed out a very sobering fact to us: At this rate, in about 40 years time we will no longer have a lake here!
But on a more positive note, the surrounding forests around the lake are largely unmodified. This means they were mostly safe from the West Coast logging. Most of the region was deemed to costly to log due to the remoteness of the area and difficulty of the terrain.
Kahikatea trees are now very rare in New Zealand, but abundant through much of the forest that backs the lake. The kahikatea wood was treasured for it’s neutral smell and taste, and was used to encase butter that was exported from New Zealand. The trees can grow up to 65 meters tall and have the ability to root themselves deep into swampy regions (this is why they grow here in the Wetlands).
As we paddled along the Wetlands, we felt small sitting in our kayaks next to these giant root systems. This is an example of climax forest – at it’s most mature state.
Jim took us for a walk through the wetlands after we’d paddled alongside the intricate root systems. He showed us the crack willow which is an invasive tree that is thriving in this region. We were also stepping over cattle prints from the cows that had escaped the night before. There are many plants which DOC are currently planting and nurturing to help restore the forest, and others which they are trying to get rid of.
He stressed the importance of separately livestock and freshwater-ways. Wetlands and freshwater streams are really important and we’ll need to think of some new sustainable ways to keep them around for generations to come.
Here’s one of the ‘good plants’ – a grass which is nitrogen and helping to restore the soil:
All in all, it was a great day! The group that we took out were very interested in what Jim had to say and good times were had all around. Thanks Jim, and Sarah-Jane from DOC and to my team at Franz Josef Tours for helping scrub out the muddy kayaks afterwards! Looking forward to doing it all again next year.