Sunday, April 17, 2011

New Zealand Nature, Sea to Summit

Our whirlwind tour of New Zealand let me encounter a broad range of natural habitats extending from seashores to mountain summits.  Beaches, coastal forests, mountain forests, alpine grasslands, and valley grasslands presented opportunities for me to learn new species of plants (80% of the New Zealand flora is endemic) and animals and to experience the physical environments in which they live by beachcombing, hiking, backpacking, and camping.  Even driving through a vast extent of country let me observe broad patterns of geology and vegetation through the windshield, augmented by glimpses of roadside plants and animals and brief forays into natural areas adjoining rest stops. In the following synopsis, I have organized my observations by five major communities and have provided weblinks (clickable from the headings) to slideshows of landscapes, vascular plants, mosses, lichens, birds, mammals, and insects: 

Seashore - We visited the seashore in several places during our loop around South Island, including Marlborough Sounds and Abel Tasman National Park on the east coast (South Pacific Ocean) and at Ross, Knight's Point Lookout, and Milford Sound on the west coast (Tasman Sea).  We frequently saw seals, shells, shags, sea-stars, and seaweeds.  On our very first walking day, I enjoyed finding familiar-looking Sunburst and Sinewed lichens adorning trees and fenceposts on a bluff above the ocean along the Kaikoura Peninsula Walkway.  Our visit to Bushy Beach Scenic Reserve on our last night in New Zealand was one of the most interesting because we saw yellow-eyed penguins coming ashore to roost at dusk - my first encounter with a penguin outside of a zoo. 
Coastal forest - A band of forest comprised of large conifers mixed with smaller hardwood trees occurs around the perimeter of South Island at low elevations.  The largest trees belong to a family of conifers (Podocarpaceae, the "podocarps") that is almost entirely restricted to the Southern Hemisphere.  Their conifer cousins are familiar to us in the Northern Hemisphere as pines, firs, and spruces (Pinaceae); in fact, early British settlers called the podocarps "pines", a botanically incorrect but widely adopted common name that has persisted to the present day.  One of the largest and most common podocarp trees in the coastal forest is Rimu (Dacrydium cupressinum), which typically rises far above the canopy of surrounding broadleaf trees.  Common broadleaf trees beneath the conifers include rata, kanuka, and low-elevation beeches.  Tree ferns are also a conspicuous part of the broadleaf community.  I encountered coastal forest early during my botanical learning curve in New Zealand and was overwhelmed by the species diversity, especially by the number of ferns and epiphytes

During our stay at the Hopewell Lodge in Marlborough, I also saw several characteristic animals of the coastal forest, including weka (a rather tame, chicken-like bird that boldly walked onto the porch of the hostel), weta (a wingless cricket that resides in caves and heavily forested habitats), and the troublesome possum (a large squirrel-like mammal introduced as a fur-bearer which has wreaked havoc on native trees).  I especially enjoyed a noctural outing along a primitive forest track to a moist ravine where thousands of glow-worms on a roadside claybank collectively emitted a constellation of tiny, eerily green lights.   

Possum (night flash photo)
Glow-worm nook with "fishing lines"
secreted by larva for capture of tiny insects

Mountain forest - This was the community in which I spent the most time (our 5-day tramp along the Routeburn and Greenstone tracks was mainly through mountain forest) and was best prepared to appreciate its natural history (from several days of study of my newly acquired Nature Guide to the New Zealand Forest).  As a botanist, it was an exceptional treat for me to encounter the famous beech trees of the Southern Hemisphere (the evergreen Nothofagus, sister to our deciduous beeches (Fagus) in the Northern Hemisphere) and to wander beneath their large, dominant crowns amongst a lush, diverse flora.  At high elevations in the mountains, mosses and lichens become astoundingly abundant, covering the forest floor, smothering logs and rock outcrops, cloaking tree trunks, and festooning high branches.  All visitors, botanists and lay people alike, are quickly enchanted by these "goblin forests".

Although the entire flora was fascinating, I was especially thrilled to meet my first filmy fern, a special family of rarely seen ferns that thrive in the very wet habitats of rain forests and waterfall spray zones.  The large size reached by lichens also amazed me; many of them (like Pseudocyphellaria "specklebellies") resembled lettuce leaves pinned incongruously onto tree trunks.  Among animals, I found zigzag tracks in the strap-like leaves of wild flax that insect detective Charley Eiseman identified as the work of a moth larva.  The most common bird that I encountered in the mountain forests was the New Zealand Robin (resembling a large junco in appearance), a very tame and intently curious bird that would materialize onto the hiking trail next to my feet whenever I paused for a rest.  Being insectivorous, they would unabashedly investigate the leaf litter disturbed by my boots in search of newly exposed insects, even perching on my toes for a better vantage point!

Specklebelly lichen on tree trunk

Filmy ferns on forest floor

Alpine grassland - We spent one glorious, long day in this habitat when we tramped from Routeburn Falls to Lake MacKenzie in the Southern Alps.  We left beech forest behind as soon as we started from the hut that morning; for the next 10 kilometers, we hiked above treeline through a rolling, grassy landscape providing spectacular vistas of rugged mountain peaks, glaciers, and deep, wooded valleys.  The dominant grass was snow tussock (Chionochloa pallens), forming dense, tawny stands.  Interspersed with the tall grasses were many flowery forbs.  I recognized gentians and buttercups resembling species I had seen in North American alpine zones, but others were completely new to me, including tall yucca-like "Spaniard" (Aciphylla colensoi), long, bunched leaves of grass-tree (Dracocephalum longifolius), and green-fingered sprouts of hebe (Hebe ochracea).  The most unique plant I found was a large wind-resistant cushion plant with the odd name of "Vegetable Sheep" (Raoulia); I discovered a single, pillow-sized patch of it during a side-trip when I struggled from Harris Saddle up to the summit of Conical Hill (my highest NZ point at 1350 meters), which afforded even more spectacular views of the alpine landscape. 

Vegetable Sheep, alpine  cushion plant


Valley grassland -  We returned from the summit to the sea by descending through mountain valleys.  Peg and I tramped for two days down the length of the Greenstone Valley, a route that passed through extensive grasslands on the valley floor.  Near its headwaters, the valley was often wet, boggy and dominated by sedges, but dry grassland prevailed in its lower end, strongly dominated by copper tussock grass (Chionochloa rubra). Mosses and lichens were abundant on rock outcrops and on talus slopes beneath old avalanches, particularly foam lichen (Stereocaulon coricatum).  A distinctive "lace lichen" (Cladia retipora) inhabited the grassland itself wherever grasses were shorter from thin soils or grazing pressure.  After returning home, I learned that the red, rock-covering lichen that I saw nearly everywhere in open sunlight was not a lichen at all, but rather a red-pigmented green alga named Trentepohlia. 

Copper tussock grass
Foam lichen

Lace lichen

Trentepohlia on streambank rocks

The sea came back into view as we completed our journey around the island, also concluding my sea to summit survey of this beautiful place.