An exploratory faunal survey of New Zealand temperate rainforest epiphytes

I'm very excited to announce a new publication on New Zealand epiphytes and the fauna that inhabit them. Hot off the press this week, this paper reports the results of a small exploratory study in the canopy of the temperate Waitakere rainforest. The project was undertaken by NZ Epiphyte Network student Olivia Henwood (who has previously posted on this blog), myself, and entomologist Brian Cutting.

The temperate rainforest of the Waitakere Ranges. Photo: C. Kirby.

Last summer our team installed cameras in the canopy of Northern rata and kauri trees with the help of Ark in the Park volunteers. The cameras were directed at nest epiphytes (Collospermum and Astelia species) and epiphyte mats (comprised of small mantling species like Cardiomanes reniforme). We also took samples of substrate from within and around the epiphytes. Our goals were to 1) find out what, if any, fauna use epiphytes for habitat or other resources and 2) investigate different canopy research methods to guide future studies.

A camera set up (top left of image) to film the activity in a Collospermum hastatum. Photo: Olivia Henwood.

After a huge processing effort from Olivia and Brian our small study produced 1,003 video sightings from over 200 hours of footage and 794 collected specimens. This was surprising given the low intensity, exploratory sampling design but we were even more surprised by the diversity of organisms recorded. Here is a snapshot of the results:

From the video: the most frequently recorded taxonomic groups were spiders (249), moths (179), cockroaches (172) and weta (156) but the most exciting record was that of a gecko (speculated to be a forest gecko (Mokopirirakau granulatus)) that was sighted on two different nights in the Collospermum hastatum. If you've got good eyes you might be able to spot it in these still shots:

Still images from the footage of a gecko sighted at night in a Collospermum hastatum. Photos: Olivia Henwood.

From the samples: samples of organic matter produced 701 invertebrate specimens while samples of phytotelmata (water bodies within epiphytes) produced 93 specimens. The most exciting find was that of the copepod Attheyella lewisae which has only ever been found on mossy stream banks before now.

Phytotelmata are often present in epiphyte communities, especially in the base of Collospermum hastatum leaves. In this study a new record of Attheyella lewisae is reported from epiphyte phytotelmata. Photo: C. Kirby.

Methods: we used tree climbing to set up cameras, collect samples and do timed visual surveys. The visual surveys did not return enough samples to process but the other two methods were useful. We speculate that the drought conditions of last summer influenced our results and that different methods may be useful in different forest types and under different climatic conditions. 

This study has provided a useful indication of the diversity of faunal species that inhabit or visit epiphyte communities and we believe that this relatively unknown canopy community certainly needs further investigation. This study has also shown that a range of survey methods is likely to be required to accurately sample the huge range of lifeforms that are present in the canopy.

Here is the link to this paper if you'd like to know more:
Henwood, Kirby, Cutting 2014