Will Land Restoration Improve Cave Biodiversity?
November, 2023 by Anna – Land regeneration, Cave Biodiversity, Citizen Science
We had a great opportunity to find out. Landowners in the Te Kuiti area were keen restore native bush on their property around two cave entrances.
We conducted the first ever pre-restoration cave biodiversity survey in 2019, the baseline for future monitoring surveys.
Two caves with entrances on farm paddocks had next to no cave life in the cave. In the entrance areas we found mice droppings, sandflies and flies and many different surface spider species, likely hiding from predators in the entrance during the day.
In contrast, we found cave wētā, glow worms, cave harvestmen, cave beetles, cave snails and cave millipedes in caves on the same property with entrances surrounded by native or recovering bush.
Approximately 6 hectares of land are now fenced off, and will slowly be replanted with a mix of native plants and trees including mahoe, cabbage trees, harakeke, tarata, kanuka, totara, toetoe and black matipo.
An important take-away is the use of photo-point monitoring. We took photographs of the general area and cave entrance from different points and took aerial videos from a drone.
Although not quantitative, photo-points provide a relatively simple and objective tool for tracking change in vegetation through time, and our goal is to expand on the initial photo collection and create permanent photo monitoring sites. This makes it an awesome tool to use to compare cave species populations to bush regeneration (read more FAP 2021).*
No study like this was performed yet in Aotearoa, so it will be really interesting to follow the bush regeneration and see if we find more cave life in the entrances over time.
Caves and karst fall under the title of ‘threatened naturally uncommon ecosystems’ so they are really important to conserve and protect. They’re also rich in animal and plant life, many with unique, unusual, and sometimes even strange morphological, behavioural and ecological adaptations.
Cave obligate species are karst specific, and sometimes only present within a single cave system, making them extremely vulnerable to surface changes – an important consideration in the management and protection of catchments of cave systems.
*Norton, D New Zealand Farm Assurance Handbook Version 1 (September 2021); Photos: Nicole, Anna and Peter Bexter (below).
