Saturday, 9 June 2012

An estuary walkabout ~ Kaikorai Lagoon and Island Park Reserve

This lagoon looks like an estuary, but has a shallow outlet which may preclude 'estuary' status.  It is certainly tidal, however, and its ever-changing appearance is a delight.  I've driven past it many times and often admired the watery vista, but I hadn't stopped to explore it or even known what it was called.  One day last summer I decided to do so.  I was glad I did!  

The estuary is just south of Waldronville, an outlying suburb of Dunedin on the main route to Brighton.  It is formed by the Kaikorai Stream where it meets the sea.  The parts closer to the sea are salty whereas the more inland portion is more of a freshwater swamp.  Both the reserve and the watery area it overlooks cover a large area. 


The reserve is announced by an unobtrusive sign on the seaward side of the road and the turning to the parking area is a short distance beyond that.  The view above is across a swampy area just before you reach the car park.  There is another car park on the other side of the road.

The track I took runs along the side of the estuary in the direction of the beach, which is quite some distance from the road.  The tide was well out leaving large areas of sandy ground exposed.  This is the view back to the road which runs along the far shore:


Tyre marks showed that vehicles had been driven around there.  This sort of thing really annoys me.  Estuaries are sensitive environments and not helped by such intrusion.  Besides, for those who bother to look there is so much to see, and the peaceful expanse is wonderfully refreshing!


In this view out towards the beach Green Island seems to float on the sea quite close to the shore.  In fact it's much further out to sea than it looks:


The thick mat of vegetation in the image below is a salt meadow and composed of salt-resistant plants which secure the sand and form a special ecosystem for many small plants and organisms.   


Such meadows are an important early step in securing sandy areas which eventually make it possible for other species to take root there.  As you can see below the growth is dense, low-growing and all on a small scale:

Glasswort (The grey plant) and Sea primrose

A bird's feather had fallen among the vegetation:

Mimulus repens

Here the plants expand their tiny rootlets into the loose sand:

Sea primrose

The clump of Mimulus repens shown below is just getting started: new shoots of this little plant reach out in all directions.  It is described by the NZ Plant Conservation Network as being 'Naturally uncommon', therefore take care not to stand on it, or on any of these plants for that matter, if you can avoid doing so.

Mimulus repens

Cotula coronopifolia, and tiny threads which I think may be Eelgrass (Zostera)

Identification of these plants is the best I could arrive at from sources I was able to find.  I've placed a list of these at the foot of this article.  If any reader has better knowledge, sources or corrections I'd be glad to hear of them.

Having admired these small plants I resumed my walk out in the sandy area but almost immediately became occupied with looking at patterns the wind had made in the sand...


The thread-like form below is a pine needle.  The sand had dried with a certain crispness and had then been gently eroded by the wind creating the delicately sculpted shape around it:


When I got as far as the edge of the dunes the sea was still some distance out, so I decided I'd gone far enough:


I turned and wandered slowly back.  That's Saddle Hill in the distance:


Close to the edge of the lagoon my attention was caught by the tannin-stained water and reflections of the sky.


Just a few steps away patterns in the dried sand showed the precise flow of the water as it had drained away with the out-going tide.  It was so precise that it looked almost as if it was still moving!


Gazing back across the water I watched someone flying a colourful kite:


But they were quite some distance away!


Back in the car park on the inland side of the road the view extends to a whole other part of the estuary.  Look at those toetoes!  They're like pampas but not so massive or inclined to take over.  Toetoe (pronounced toy-toy) is a New Zealand native.  Pampas has also been widely planted in New Zealand.  ToeToe can be distinguished by its plumy flower heads which turn over at the top, whereas those of pampas stick straight up in tufts. 


My exploration of the area, although very partial, was very pleasant and easy, and left me with plenty more to discover on future jaunts. 

More information can be found via the following links:
More about the plants shown above:
  • Mimulus repens, also known as Native musk, Maori musk, Native monkey flower
  • Samolus repens, also known as Sea primrose, Shore pimpernel, and Water pimpernel, Creeping brookweed, Creeping bushweed, and in Maori, mākoako
  • Cotula coronopifolia, also known as Batchelor's buttons, Water buttons, Brass buttons, Golden buttons, and Buttonweed.  This plant is a native of southern Africa but has made itself at home in many other parts of the world, including Australia and New Zealand.
Definition of what an estuary is:
  • Estuary - Wikipedia article.  As well as defining what an estuary is, this article describes the ecological importance of these semi-enclosed bodies of water.
This map shows the area:
This site describes the ecological significance of the reserve and watery mass:
The freshwater source is:
If you want ideas of other places to explore you might find some here:

You can find my other articles about exploring the beach and its rock pools via the link below: 
Other articles in which I take walks and explore the natural world can be found via the link below:

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