Physical Environment
The area described in this section is Doubtless Bay, from Knuckle Point to Berghan Point, excluding the Mangonui Harbour, which is discussed separately in the next section.
From Knuckle Point southwards to Brodie's Creek, the coastline is convoluted and rocky, with rocky reefs extending into the inter-tidal. Small bays are fringed with shingle or rocky rubble. There is a small estuary where Brodie's Creek flows out into the sea. Much of this dries at half tide to expose shingle and scattered boulders, with mangroves growing in the finer sediment substrate further up the estuary.
South-west from Brodie's Creek, the coast consists of a series of rocky cliffs and promontories arising from spurs running from the Rangiawhia Range. The small sandy beaches at Whatuwhiwhi, separated by rocky headlands, are relatively sheltered, and provide a popular spot for family recreation. Whatuwhiwhi itself is a small settlement, set on the elevated hillside, with expansive views of Doubtless Bay.
Further south is Tokerau Beach, a curving, firm sandy beach over 14 km long. Tokerau Beach forms the eastern side of the broad, sandy tombolo that joins the Karikari isthmus to the Northland basement rocks. The beach faces east-nor-east to the open ocean, and receives seas and swells from that direction. The northern end of the beach is less exposed, since it receives some shelter from the Karikari Headland. A dune belt behind the beach extends throughout its length, at a relatively constant width of about 200 m. At the northern end of the beach, the fore-dune is approximately 0.8 m high, and has been artificially flattened in places (Northland Regional Council, 1995). Further south, the main fore-dune is 4-8 m high, but along much of the beach a belt of dunes around 2.5 m high lie in front. Four streams discharge onto the beach, with the largest being the Awapoko River at the southern end of the beach. This river curves around the tip of the main fore-dune ridge, and separates Tokerau Beach from Aurere Beach, a short sandy beach facing in a northerly direction. The dune formation on Tokerau Beach impounds a broad wetland area north of the midway point. Linear-shaped swamps occur behind the dunes in the southern part.
The golden-coloured sand of Tokerau Beach is composed predominantly of quartz, with significant shell content. The northern end of the beach, being more sheltered, has fine-grained sand and a gentle beach slope. Toward the southern end, the grain size becomes coarse to very coarse, and the beach slopes more steeply (Northland Regional Council, 1995). There is a small settlement at the northern end of Tokerau Beach.
The southern coastline of Doubtless Bay is formed by a series of sandy beaches, Taipa Beach, Cable Bay and Coopers Beach, separated by short sections of rocky shore that occur at the bases of small headlands. This coastal area is backed by hills.
Taipa Beach is a firm, sandy beach, 1,100 m long. Low hills to the west and Te Kuihi Hill (60 m high) to the east provide shelter from both easterly and westerly winds. The beach itself is exposed to the predominantly north-easterly swell from the open ocean, particularly at the western end. It is backed by a low fore-dune (1 to 2 m), the central portion of which has been extended by earth fill. At the western end of the beach, the fore-dunes are backed by older dune ridges up to 4 m high. The Taipa River enters the sea at the eastern end of the beach, and is deflected by the base of Te Kuihi Hill. Sand flats are exposed at low tide at the mouth of the river, and areas of mangrove are found further up the estuary.
Cable Bay is approximately 1200 m long, with a firm sand substrate on the western end of the beach, and a shelf of rock extending along the eastern end.
East of Cable Bay, and separated from it by a stretch of rocky coast, is Coopers Beach. The beach is 1900 m long, and faces the open ocean, from which it is exposed to easterly seas. The beach is backed along most of its length by a low cliff. The Karekare Stream enters the beach through a gap in the cliff two thirds of the way along toward the western end. The headland to the east of Coopers Beach, Rangikapiti Head, forms the western head of the entrance to the Mangonui Harbour.
Osprey Head, the eastern head of Mangonui Harbour, is a reef-fringed headland that protects Hihi Beach to its east. Hihi Beach is a sandy beach approximately 1,000 m in length, and backed by sand dunes. A ridge, peaking at Whakarangi (334 m), runs in a line from the eastern head of the harbour toward Berghan Point. Spurs running down from this ridge to the sea, result in a steep and convoluted rocky shoreline, extending from the eastern end of Hihi Beach to Berghan Point. The small bays indenting this coastline are lined with shingle. An exception to this is Takarau Bay, which is sandy and backed with sand-dunes. Berghan Point forms the southern head of Doubtless Bay.
Flora & Fauna
Doubtless Bay has an abundant marine life. Scallops are plentiful in the bay itself, and are frequently washed up onto Tokerau Beach after storms. Shellfish such as tuatua are also abundant in the low inter-tidal of the open sand beaches.
The many rocky shores in this area support flora and fauna similar to that described for Cape Karikari - zones of the seaweeds Carpophyllum, Lessonia and Ecklonia , preceded higher on the shore by Hormosira banksii, Corallina officinalis and Xiphophora chondrophylla in the rocky inter-tidal. A variety of invertebrates are found sub-tidally in this environment, including those of particular interest to fishers - kina ( Evechinus chloroticus ) and red and packhorse lobster ( Jasus edwardsii and J. verreauxi ).
Estuaries in Doubtless Bay provide important environments for wading birds. The estuaries are generally fringed with mangroves ( Avicennia sp. ), grading into saltmarsh containing Juncus and Leptocarpus species, followed by Samolus repens on the landward side. In some places (e.g. some areas in the Taipa Estuary) the introduced rushes of Spartina species threaten the native species such as Juncus , by competing for the same habitat. Coastal forest remnants are present, adjacent to the Taipa Estuary. The fringes of the Awapoko Estuary are especially noted for the presence of the rare clubmoss Lycopodium serpentinium.
Tokerau Beach and the swampland behind the dunes are also ecologically significant areas. The rare NZ birds, the NZ dotterel and the bittern occur in large numbers, along with the rare species: turnstone, Caspian tern, and (in the swampland) the NZ fernbird. Other more common birds are also abundant, including the reef, and white-faced herons, variable oystercatcher, grey duck, black-backed gull, pied and little shags, pied stilt, pukeko, white fronted tern, chaffinch, silvereye and pipit. South of the Tokerau Beach settlement is a population of the NZ fern Thelypteris confluens , which is highly endangered and in danger of extinction. Another very rare fern found in this area is Cyclosorus interruptus.
References:
Northland Regional Council. 1995. Proposed Regional Coastal Plan for Northland. Unpubl. report.
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