Investigating epiphytes of the Australian East Coast - by Jennifer

“It is not going to be easy” I said to my partner Steve Pearce, who had kindly volunteered to be my field assistant for the next two months. “It’s a rainforest and it’s winter. It will be cold, wet, you’ll get covered in leeches and you’ll probably lose feeling in your legs from hanging in your harness all day.” Not much of a sales pitch I will admit, however, to my thrill-seeking partner, it only added to the adventure.

And an adventure it was. 

Climbing up a giant 50m fig tree (Ficus watkinsiana). This tree was one of the largest and most diverse trees that we surveyed (©Steven Pearce).

Getting to spend 2 months in pristine forests, swinging around the canopies of majestic rainforest trees and devoting all day studying incredibly fascinating epiphytes has been one of the best experiences of my life. Back in May this year, we surveyed 50 trees over an altitudinal gradient from 300m to 1100m above sea level in the glorious Border Ranges National Park, Australia. The World Heritage listed National Park is an extensive area of subtropical rainforest that covers 3,600 square km in northern New South Wales, adjacent to the Queensland border. The aim of my PhD is to look at how epiphytes are distributed along environmental gradients of light and moisture, both within the host tree and across an altitudinal slope.

Misty days like these gave the forest such a magical air, we really felt like we were up in the clouds. This fig was one of the best trees to climb, its big spreading limbs hosting many species of epiphytes (©Steven Pearce).

We found 34 species of vascular epiphytes (18 species of orchid and 16 species of fern), including the incredibly special Beech Orchid (Dendrobium falcorostrum), which occurs exclusively on Antarctic Beech trees (Nothofagus mooreii) which inhabit the cool temperate mountain tops of the Border Ranges NP. We also found over 42 morpho-species of moss, although at this stage identification has been somewhat difficult so many are still unnamed as yet.

The Beech Orchid (Dendrobium falcorostrum) is a special orchid that occurs only on Antarctic Beech (Nothofagus mooreii) (©Steven Pearce).

Athough I am still in the tedious stage of analysing the data, some interesting patterns have already started to emerge.  Vascular epiphyte diversity was highest at around 500m in elevation, while moss diversity peaked a bit higher at around 700m. About half of the vascular species and three quarters of the moss species showed distinct preferences in their altitudinal range. For example, some of the large ferns such as the Staghorn (Platycerium superbum) and Elkhorn fern (P. bifurcatum) only occurred at lower altitudes (possibly due to temperature excluding them from the cooler mountain top), while the filmy ferns (Hymenophyllum sp.) and the Dagger Orchid (Dendrobium pugioniforme) are more common at higher altitudes where there is higher levels of moisture.

We are looking forward to next year, when we head out to undertake another season of field work in the Wet Tropics of North East Queensland. It will be interesting to compare the subtropical realm of the Border Ranges NP to the tropics of Far North Queensland. Who knows what fascinating epiphytes we will find up north?

For more information you can contact me:

Jennifer Sanger
jennifer.sanger (at) utas.edu.au
PhD Student
School of Geography and Environmental Studies
University of Tasmania

Click here for the full epiphyte photo album.

Here I am 25 metres up a tree, on a particularly wet day, saying hello to Dendrobium speciosum. This orchid is one of the most common and conspicuous orchids in the Border Ranges as it can grow up to a metre in length (©Steven Pearce).