Braided rivers

Braided rivers - taonga ecosystems in our backyard

A braided river has many channels that constantly change - in flow, intensity and width. Some channels can detach from the main flow and may become wetlands.

Why so special?

We tend to take braided rivers for granted, but their open gravel beaches, shingles, and freshwater for swimming and fishing make them quite rare, especially in the North Island. They support native flora and fauna which has adapted to the dynamic ecosystem in Aotearoa. Birds such as banded dotterel, black-fronted dotterel, and black-billed gulls depend on braided river habitats for breeding.

These days, the most common plants beside braided riverbeds originated from overseas. There are very few places in Hawke’s Bay where original, native plant communities survive.

Threats

Human activity often threatens braided rivers and the life that depends on it. Take weeds for example – they displace native plants and change open gravels into swathes of weeds. When it gets too weedy, river birds can’t breed there.

Predators are also a threat to river birds. Their camouflage defence colourings are utterly defenceless against introduced predators such as hedgehogs, feral cats, rats and mustelids.|

Recreational activities also affect breeding success. Again, these birds are defenceless against 4WD vehicles, dogs and even accidental trampling. Their nests and eggs are very difficult to spot.

With all of all these pressures, many of the braided river birds and plants are classified as ‘threatened’ and are declining. Braided rivers themselves are an ‘endangered’ ecosystem.

What we’re doing

To help protect this fragile ecosystem, Hawke’s Bay Regional Council does not beach rake rivers during the breeding season, and surveys the area for shore bird nests prior to gravel extraction. Outside of the breeding season, beach raking helps keep weed cover down on many river sections and actually helps birds use our rivers for breeding. A recent river bird survey found good numbers of threatened shorebirds using braided rivers for breeding.

To support the native plants, the Regional Council has a weed control programme to protect six small native remnants by the lowest areas of the Ngaruroro river, and is protecting some of the last native seed sources in the area.

What can you do

River birds are particularly vulnerable when they are incubating eggs and raising chicks, from November to March. You can help these birds:
• Keep your dogs on a lead
• Watch out for the hard-to-spot nests
• Drive slowly if you’re on a riverbed
• Stay at least 10 metres away from nests
• Spread the word