Nonvascular epiphytes are the mosses, lichens and liverworts that we find growing on other plants. They do not have the plumbing systems that higher plants have to pump water and resources around their stems and leaves. This means no xylem or phloem and a generally small stature.

Nonvascular plants are a very important group epiphytes. They are commonly the first epiphytes to colonise a young, bare host tree and provide substrate that other plants require for attachment. They contribute to forest biodiversity and processes and can be found from the bottom to the very top of host trees.

The trouble with nonvascular epiphytes is that they are hard to identify. This means that they often get overlooked in epiphyte surveys and studies. Dr Kathrin Affeld discussed in her talk at the 2013 NZ Epiphyte Workshop the importance and challenges of including these plants in epiphyte studies. I admit that I know very little about New Zealand’s nonvascular epiphytes and have not found any feasible way to include them in the NZ Epiphyte Survey Programme. I am very interested in any thoughts on this – how can we start paying more attention to nonvascular epiphytes?

Today was the University of Waikato Open Day - an event where prospective students come to see what the University has to offer and what it means to undertake tertiary study (and of course, get lots of free stuff!).

Olivia and I set our ropes up in a Ginko biloba for a tree climbing demonstration. It was very branchy and required some careful manoeuvring around smaller limbs but overall a pretty straight-forward and enjoyable climb. 

We had a few conversations with students but unfortunately the rain seemed to deter most from hanging around. Our goal was really just to let them know what studying biology can lead to - real life adventures! 

Hopefully we sparked the interest of some young minds who could become our next epiphyters :) Here are some photos from today and other tree-climbing expeditions.

I'm Olivia Henwood, a student at the University of Waikato. I have recently spent four weeks carrying out an epiphyte research project in the Waitākere Ranges. Here's brief a snapshot of my trip:

This is a good day in the office! Ascending a rata to install a camera.

Stunning view over the Waitākere Dam and sun-soaked ranges beyond.

Camera ready and waiting to unlock the secrets of the tree canopy...

Sharon Osman, one of the amazing Ark in the Park volunteers happy to get an opportunity to utilise her skills.

Massive Collospermum hastatum nest - this must be at least 4m tall!

Giant cave wēta - close to 30 cm stretched out! Just one of the many treasures living within the epiphytes. More to be revealed soon...

In a new viewpoint article, Professor Gerhard Zotz has clarified the use of ‘hemiepiphyte’ and proposed the rejection of the term ‘secondary hemiepiphyte’.

The current classification of canopy plants typically has three main groups: (1) holoepiphytes; (2) hemiepiphytes; and (3) climbing plants. Holoepiphytes are those that germinate and complete their life cycle on other plants. Climbing plants are vines (also called lianas) that require the structural support of other plants to reach the canopy; these can be further defined as herbaceous or woody categories. Hemiepiphytes are plants that have a root connection with the forest floor at some stage in their life cycle and can be further differentiated into primary and secondary categories:

• Primary hemiepiphytes are plants that establish this connection to the ground after germinating in the canopy 
  

• Secondary hemiepiphytes begin life on the ground, climb to the canopy and then lose their link with the ground. 
  

This is how the current classifications relate to each other (please note that this is my interpretation):

Classification of hemiepiphytes has been confusing for many years – especially secondary hemiepiphytes (SH). Here is a conceptual picture of the difference between primary and secondary hemiepiphytes that I’ve drawn and below that, a list of problems with these classifications.

The problems:

As explained by Zotz (2013), there are multiple problems with the term ‘secondary hemiepiphyte’:

1.      Inconsistent use of SH has resulted in ambiguous application of the term and confusion over which species fit in this group.

2.      It is difficult to determine if any one species is a SH because although the main ground connection may be lost, adventitious roots can re-connect with the soil and these roots can be hard to find and trace.

3.      The term implies a close relationship with primary hemiepiphytes when there are in fact significant functional differences between the two groups, including: the location of germination; the growth form; the source of water and nutrients; and the structural support mechanisms.

A solution:

Zotz (2013) proposes that the use of the term SH is discontinued and that all climbing plants which germinate on the ground and possibly lose parts of their ground connection are instead referred to as ‘nomadic vines’. This change would achieve the following clarification:

1.      It should stop the ambiguous classification of canopy species and facilitate compatibility of data sets in higher-level studies. Also, the use of ‘primary’ with hemiepiphyte will be redundant and ‘hemiepiphyte’ will only refer to species that germinate on another plant and establish a connection with the forest floor.

2.      There will no longer be an implied functional relationship between the primary and secondary hemiepiphytes but instead the similarity of SH with vines/lianas will be highlighted

3.      Species that only sometimes lose their connection with forest soil will fit within ‘nomadic vines’. This new term can also accommodated the occasional germination of these species in the canopy.

This is how the proposed classifications relate to each other when based on the location of germination (please note that this is my interpretation):

What are your thoughts? How does this new classification apply in New Zealand? Do you think any of our species can be classified as nomadic vines?