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Coastal lizards of New Zealand

By Moniqua Nelson-Tunley from Waikato Regional Council

New Zealand’s lizards are often described as our forgotten fauna. They are often overlooked in conservation projects because they are more cryptic (harder to find) than native birds- but they are also more diverse and threatened than our native birds. There are currently 105 species of native skink and gecko, some of which haven’t been formally described yet (new species are being discovered on an almost yearly basis). Only nine of these species are considered “Not Threatened”, leaving 96 species (91% of our lizard fauna) at risk or threatened with extinction.

One species, the cobble skink, was discovered less than 10 years ago and the entire population (only 40 animals) is held in captivity because their coastal habitat was destroyed. The cobble skink was abundant along a discrete patch of boulder beach coastline near Westport. In the 10 years since it’s discovery, the species rapidly declined until the last population was trapped between the Granity pub and the Tasman sea on an eroding piece of beach. The future for this species is bleak unless its habitat is restored and the species returned to the wild.

But it’s not all doom and gloom. Thanks to restoration and pest animal control, a few lizard species are beginning to recover. There have been a number of successful projects where pest control (or eradication when possible) combined with restoring native vegetation has resulted in increasing lizard populations. The key things to keep in mind when restoring habitat for any animal are; what do they eat (food sources), what eats them (predators), and where do they hide (refuges).

There are mountains of evidence about the impact pest mammals have on native wildlife. You are probably familiar with the war on rats, possums and mustelids, but mice and hedgehogs are also major lizard predators. Rats and mice are possibly the worst of the bunch because they affect all levels of the ecosystem, eating seeds, eggs, chicks, invertebrates and lizards.

Being ectothermic (cold blooded) makes lizards especially vulnerable because if a predator finds them during winter they don’t have the energy to run away. Smaller lizards can hide in small cracks and crevices where only a mouse can reach them, but the larger lizards aren’t so lucky. All of our larger skink and gecko species are either safe in predator-free reserves, or rapidly declining due to predation. On pest-free offshore islands the lizard populations increase exponentially. Pest suppression on the mainland also results in native species recovery, but the control needs to be long-term in order to keep the pest numbers low.

It can be difficult to control pest animals in a dune environment due to the high level of public use and interest in the area. Early engagement of the community and signage to inform visitors can go a long way to getting support for pest control in amenity areas. Another way to yield benefits for the coast is to encourage adjacent landowners to control rats on their properties- no-one wants a rat nesting in their roof! The self-resetting trap technology (by Goodnature) is very convenient for non-resident landowners. With the huge enthusiasm for Predator Free NZ, now’s a great time to start a pest control group.

I’m sure you are all aware that the iconic green pastures of New Zealand were once vast wetlands and forests. Hopefully you are also aware that the destruction of New Zealand’s natural environment is ongoing. Coastal environments are no exception, and in fact are often more heavily impacted by human modification than most other ecosystems. Your dune restoration projects are helping turn the tide (figuratively speaking) of coastal ecosystem loss in New Zealand. The best action you can do to help protect coastal lizard populations is to continue the good work you are already doing- plant a variety of native species in and around your dunes, rocky shores, boulder beaches and coastal forests. Lizards eat small invertebrates (like sand hoppers, flies and moths), nectar and small fruit. In dunes, planting flowering and fruiting plants like sand coprosma and pimelea provides a great food source for lizards, as well as attracting insects. Knobby club rush (wiwi) and muehlenbeckia within backdunes provides dense foliage which makes great lizard habitat. Geckos love licking nectar from pohutukawa and flax flowers.

Another activity you might already be intuitively doing is planting to connect nearby patches of existing habitat. This is extremely valuable for lizards and other small animals. Imagine how hard it is for a 5cm skink to run across 2000m of sand to colonise a new dune. By planting between existing vegetation, you are creating dispersal corridors that make it much more likely that the little skink will succeed in finding a new home.

Does your coastal restoration project conduct beach clean-ups? Removing plastic and other rubbish from the beach is a great idea, but natural detritus like driftwood and seaweed can be an asset. Placing driftwood and seaweed in the dune system (while minimising squashed plants) creates refuges for lizards to escape from predators as well as somewhere to hibernate in cold weather. Natural detritus also serves other purposes- it is a source of food for native sand scarab larvae (they look like a huhu grub) and other invertebrates, it slows the wind, allowing sand and seeds to collect in the lee and providing nursery-like conditions for seeds to germinate. When the logs and seaweed eventually break down they provide natural fertilizer for dune plants.

So hopefully by now I’ve convinced you that our lizards are precious and need protection, but also that there are easy things you can do to help protect our native lizards. You are probably already doing some of the things I’ve mentioned above – thanks! Have a go at a few of my suggestions that you aren’t already undertaking.

  • Plant a variety of native plants- plant diversity supports animal diversity.
  • If removing driftwood and seaweed from the beach, place above the high-tide line within the vegetation.
  • Connect nearby patches of vegetation by planting in between.
  • Set up a pest control program on your coast and work with neighbours to expand the area where pests are supressed.

Read more here:

Cobble skink: http://www.radionz.co.nz/national/programmes/afternoons/audio/201804032/critter-of-the-week and https://www.theguardian.com/environment/radical-conservation/2017/jun/01/new-species-discovered-behind-a-pub-then-saved-from-extinction

Conservation status of New Zealand reptiles, 2015. Department of Conservation. http://www.doc.govt.nz/Documents/science-and-technical/nztcs17entire.pdf

Goodnature self-resetting traps

https://www.goodnature.co.nz/

A broad range of pest control options

https://www.traps.co.nz/

Predator free NZ- getting started

http://predatorfreenz.org/get-started/

South Georgian Diving Petrels - Student Update

Ecology, breeding biology and conservation status of the South Georgian Diving Petrels (Pelecanoides georgicus) on Codfish Island (Whenua Hou), New Zealand

 Johannes H. Fischer, School of Biological Sciences, Victoria University of Wellington

 The South Georgian Diving Petrel (Pelecanoides georgicus;SGDP hereafter) is a burrow-breeding Procellariiformes with a circumpolar distribution across the southern oceans and is currently considered “Least Concern” by the IUCN. In New Zealand, however, the SGDP has declined steeply due to a combination of predation by introduced species and habitat destruction. Subsequently the species became extinct on the South Island, Stewart Island, Auckland Islands and Chatham Islands. The only remaining New Zealand breeding population persists in the dunes of the Sealers Bay, Codfish Island (Whenua Hou), with a population size of 150 adults at most. Therefore, the species is considered “Threatened - Nationally Critical” by the New Zealand Threat Classification System. As this highly-threatened population is the only New Zealand Procellariiformes that specializes in breeding in coastal dunes, the Coastal Restoration Trust of New Zealand supported my research project aimed at better understanding the threats and population trends of the SGDP on Codfish Island. The proposed aims of this study were:

  • Continued assessment of nest site characteristics critical to the SGDP on Codfish Island
  • Assessment of population dynamics and trends of the SGDP on Codfish Island
  • Assessment of the breeding biology of the SGDP on Codfish Island

Analysis of explanatory variables that potentially affect nest site selection in SGDPs on Codfish Island using a theoretic information criterion (AICC) showed that their nesting habitat are mobile, steep, north-eastern (seaward) facing dunes no further than 20 m from the sea. In addition, the interactions between the distance to the sea and physical aspects of the dunes, as well as the interaction between plant cover and the physical aspects of the dunes proved important. Surprisingly nest site selection by SGDPs is not dictated by the presence of invasive plant species (as opposed to the indications given by preliminary results), nor by the presence of conspecifics, Common Diving Petrels (P. urinatrix; CDP), or Sooty Shearwaters (Puffinus griseus). However, four burrows showing changes in occupancy suggest that CDPs may directly compete for burrow sites with SGDPs. More importantly, the preferred nesting habitat thus renders this Nationally Critical species extremely vulnerable to effects from stochastic events (e.g., storms and storm surges) during the breeding season. These results have been written up as a formal publication.

During the 2015/2016 breeding season, 60 SGDPs were banded and these individually recognizable birds presented a unique opportunity to assess population dynamics of this species. Therefore, continued banding and recapture efforts have become a priority during the 2016/2017 breeding season. During the first field trip of the 2016/2017 breeding season (late September to early October 2016), an additional 47 SGDPs were banded. Furthermore, 31 SGDPs were recaptured (21 from 2015/2016 breeding season, 3 from 2008/2009, 4 from 2004/2005 and 1 from 2003/2004). This data will form a solid foundation for a detailed study aimed at understanding the population dynamics and trends in the SGDP. Banding and recapture efforts will continue in upcoming field trips and breeding seasons to further compile the data.

The third aim, the assessment of the breeding biology of the SGDP on Codfish Island, is crucial to enable the continued existence of this species. Unfortunately, it was not possible to deploy the required study equipment (study burrows) during the first field trip due to logistical and bureaucratic constraints. Preliminary data on the breeding biology were collected during the first field trip (by assessing body condition of birds in the hand) and these data suggest prospecting to start in September, while incubation appears to start in the first week of October. Future attempts to place study burrows are currently being considered, as well as a study trial to assess the effects of study burrows on brood-chamber conditions (e.g., temperature and humidity).

In conclusion, the smooth progress of the analysis of the nest site selection of the SGDP on Codfish Island will enable more fine-tuned conservation strategies in the future. The first SGDP field trip of the 2016/2017 breeding season was a remarkable success in terms of capture-mark-recapture efforts. In addition, future field trips may enable the study of the breeding biology of this Nationally Critical species. I am thus very grateful for the support received from the Coastal Restoration Trust of New Zealand to further our understanding of a species in such desperate need of conservation management.

Introducing 2016 Student Award Winner Johannes Fischer

Johannes is studying for an MSc in conservation biology at the School of Biological Sciences at Victoria University, Wellington. He is studying the ecology, breeding biology and conservation status of the South Georgian Diving Petrel (Pelecanoides georgicus). The South Georgian Diving Petrel is listed as nationally critical and is the sole Procellariiformid seabird in New Zealand that only breeds in sand dunes. If that is not enough to spike your interest; it might also be an undescribed, cryptic species!

The only extant population of South Georgian Diving Petrels in New Zealand is located at Codfish Island (Whenua Hou), off Stewart Island. Invasive predators have been removed from Codfish Island more than a decade ago, but the population does not appear to be increasing in size. Vegetation encroachment and erosion have been put forward as potential hypotheses for the lack of population growth. Therefore, the focus of the study is to assess the nest site selection of South Georgian Diving Petrels at Codfish Island. Habitat selection is an important part of ecological research.  Understanding if and why species prefer certain habitats and avoid others is crucial to successful conservation management. Through this research dune management may be implemented specifically to aid the South Georgian Diving Petrels on Codfish Island.

Stay tuned for further updates from Johannes.

Restored dunes supporting more pipi/tuatua

A joint project between tangata whenua, Māori researchers and ecologists, has found that toheroa, which was once abundant on the Horowhenua coastline, and still prized by tangata whenua, have been reduced to very low numbers between Hōkio and Ōtaki.

An associated study assessing Escherichia coli (a bacteria that indicates faecal contamination) clearly indicated that the shellfish that remain are regularly contaminated with faecal material and thus unsuitable or only marginally suitable for human consumption, in terms of Ministry of Health guidelines. This contamination is of great concern for cultural and health reasons. Land cover data showed a dominance of particular land covers in the adjacent catchments, which can contribute to this contamination.

The study was a part of the Manaaki Taha Moana project through Taiao Raukawa with Iwi and Hapū, and in association with Cawthron Institute and Massey University. The research is assisting tangata whenua in their work with councils, scientists and other local interests to address habitat degradation and consider re-seeding of taonga species.

Coastal Restoration Trust Trustee, Tim Park comments that “It’s very interesting that this research found the largest tuatua populations at Waitohu. It’s a long way up the coast from Hōkio to Ōtaki! It’s intriguing that five to six times more tuatua were found at the South Waitohu sample site than most other places they sampled in this massive study area.”

“Its great that the award winning care group Waitohu StreamCare has been actively restoring the dunes in this area for some time with the longstanding and ongoing support of Kapiti Coast District Council and Greater Wellington Regional Council. As well as the revegetated dune areas, the area is also home to some of the most intact natural foredunes in the Foxton Ecological District and are dominated by the sand-binder, Spinifex.” Tim said.

“I’d like to think that the comparatively high number of tuatua found at Waitohu has something to do with the naturalness of the ecosystem. Heathly beach systems are usually able to support more native species and are also more resilient to natural and human impacts. There is some evidence from Northland that the toheroa lifecycle depends on native sand binders. I wonder if this is also true for other shellfish species”.

Dr Huhana Smith from Taiao Raukawa says “A customary Māori worldview would understand and respect the natural interrelationships between coastal native plants and shellfish. However, we believe that intensive agriculture, exotic forests and extensive wetland drainage within the case study catchment areas has impacted on our ability to support and maintain those relationships. This land use change is considered one factor amongst others that has led to the overall decline of shellfish populations, which we consider are taonga.”

The faecal contamination and land use changes for kaimoana reports will be available soon at http://www.mtm.ac.nz/ or for more information contact Dr Huhana Smith Enable JavaScript to view protected content. , Emma Newcombe Enable JavaScript to view protected content. or Craig Allen Enable JavaScript to view protected content.

Globetrotting 2013 Study Award Winner Progressing Nicely

The 2013 recipient of the Quinivic/Coastal Restoration Trust study award, Renee Johansen is currently being hosted at North Carolina’s Duke University and continuing her research examining root fungi in marram and spinifex. She has been travelling extensively, collecting root samples from marram in California and most recently, the United Kingdom. Renee has provided us with an update on her work:

Perhaps the biggest lesson I have learnt during the first two years of my PhD is that research is an inherently unpredictable activity, in terms of both what will be discovered, and the time that discovery can take! Extending my time in the US by twelve months has enabled me to change the focus of my project in response to fast moving technological developments in my field and to my own early discoveries. While I am still using DNA sequencing to look at whether fungal communities in dune grass roots differ by host plant species, I have broadened my survey of fungal diversity in marram to include samples from the plant’s native range. Now, comparing fungal diversity in different countries is a major focus of my project and I will be taking a more thorough look at whether New Zealand is likely to harbour endemic fungal species in the dune environment. In June I visited the United Kingdom, travelling by bus and train up the west coast from Devon through Wales to Liverpool, collecting marram roots from seven different sites. This coastal zone suffered heavy storm damage during the last northern hemisphere winter and many of the fore dune systems lost several meters from the dune toe. Fortunately I was able to find systems which were extensive enough to retain good quantities of marram, and in some cases the remaining marram seemed to be benefiting from partial burial by the large quantities of sand delivered to some areas by the storms. These plants had lots of young, vigorous growth. It was great to witness the dynamic nature of the coastal environment first hand, mix with lots of coastal enthusiasts who volunteered to work on the project, and add to my sample collection which now numbers 392 root sections from four dune grasses and three countries.

My current greatest challenge is optimizing my DNA sequencing methods in order to get the best possible information from those samples. I will be working on this for the next two months before heading home to further explore the fungal diversity in New Zealand dunes. Preliminary results from the pilot study I did at Anawhata in Auckland’s Waitakere ranges before I left show that spinifex supports a wide range of beneficial root dwelling fungi – some known from dunes elsewhere in the world, and some which are probably new to science. Some of these may be endemic to New Zealand. I plan to gather more genetic information for these fungi, and hope to look at their morphology as well, with a view to formally describing them. I am also looking forward to presenting at the next Coastal Restoration Trust conference.