Braided river plants, lichens, and mosses: an overview
Many species of native plants are found in braided river beds, some of which are cryptic and uncommon. Until recently they were largely overlooked, and yet they play a vital role in the ecology of braided rivers. A few distinctive and reasonably easy to recognise species are included here, each with links to the New Zealand Plant Distribution Network, the most comprehensive online database for New Zealand native (and exotic) plants.
From DOC’s website: “Despite the apparent sparseness of riverbeds, a recent survey found over 300 hardy yet beautiful native plant species 35 mosses and liverworts and 41 lichens, forming mosaics of distinctive communities in the riverbeds and adjoining wetlands of the Mackenzie Basin braided rivers.
Twenty-three different threatened plants were recorded from upper Waitaki riverbeds and wetlands in this same survey. Prior to this work, the riverbeds were not thought to contain any rare or endangered plants.
Typical early pioneer species include various encrusting lichens, mosses, tiny cushion plants, willow herbs and wispy native grasses.
With time these plants form blankets of plant cover and other tussocks and woody shrubs slowly establish, in turn becoming the dominant plants. The whole process is dynamic, often being disrupted by changing river channels and scouring floods resulting in the mosaic of vegetation development typical of braided riverbeds.
Some eye-catching species include the prostrate shrub, Helichrysum depressum, with its cryptic grey foliage and contrasting white fluffy seed heads, Pimelea prostrata, a native daphne with a profusion of small, white, scented flowers and the cushion plant (forget-me-not) Myosotis uniflora with tight cushions of delicate, white or lemon flowers.”