Hedgehogs: Prickly Pests on the Rampage

Posted by Cathy Nottingham @cathy28495357 

Hedgehogs are an underrated mammalian pest in New Zealand – there are even groups of people who ‘rescue’ them.  Hedgehogs have been shown to have an impact on native ground-nesting bird, lizard and weta populations, but little research has been carried out on them in urban environments. In particular, we don’t know what their impact might be in urban forest patches (fragments).  That’s where I come in, for my Masters research project, I’ll be investigating the impact of hedgehogs in urban forest fragments.  I’ll look at what hedgehogs are feeding on in this environment through gut content analysis.  I’ll also be working on understanding the relationship between the number of hedgehogs in a forest fragment and the severity of the impact. This is called a damage function. This will enable managers and community groups to initiate hedgehog control once their abundance surpasses a critical impact threshold.


Hedgehog. Photo credit: Gaudete / Wikimedia Commons / CC-BY-SA-2.5

Having recently received permission from the council to start working in the reserves, I’ll will be soon heading out at night to find hedgehogs.  This will involve using thermal imaging cameras, volunteers and some oven mitts!


Thermal image of a bird using Seek Thermal Camera

As part of creating a damage function, I’ll be using crickets (as a proxy for weta) and quail eggs to measure survival or death by hedgehog. Camera traps will be used to monitor predation by hedgehogs, and the survival rates of the experimental crickets and eggs. I’ll be using chew cards to monitor the relative abundance of hedgehogs and rats in the reserves. With councils and community groups increasingly controlling rodents in bush reserves to help native birds, might this let the hedgehogs run rampant?  So remember, next time you see one of these prickly pests, ambling along at night, there is a killer in your midst, but I’m on the case, and I’m planning on finding exactly what they are up to in our urban bush patches.


Trialling predation experiments: using crickets and camera traps to monitor hedgehog predation


cathyCathy is a MSc student in the Centre for Biodiversity & Biosecurity, School of Biological Sciences, University of Auckland. She is investigating the impact of hedgehogs in urban forest fragmentsShe is supervised by Margaret Stanley and Al Glen.

How to get the most out of a writing retreat

Posted by Cate Macinnis-Ng @LoraxCate

This week a group of us from the Centre for Biodiversity and Biosecurity had the pleasure of attending a writing retreat at the fabulous Aio Wira Retreat Centre in the Waitakere Ranges. A writing retreat is a great way to get away from the office and specifically concentrate on writing, enhanced by the pressure of others madly writing around you. Here are a few things you can do to boost productivity before, during and after a writing retreat.


A beautiful spot for some writing

  • Plan, plan, plan

Work out what project you want to work on and plan your time so you can hit the ground running when you arrive. In our line of work, a writing retreat might include data analysis, reading papers, designing experiments, preparing figures and of course, writing about it all. It can be a good idea to plan a few different tasks so if you get stuck on one, you can still make goood use of your time by getting on with another. That said, prioritising the most important tasks is still important. Perhaps discussing your plans with a colleague or supervisor will keep you accountable.

  • Gather everything you need

If a writing retreat is about progressing your work, it’s important you have everything you need to do that. Before arriving, make sure your data are in the right format, you have the references you need and you have your work plan. Bring your computer and charger or pen and paper if that works better for you. Perhaps gathering thoughts is the most important thing to do in preparation for a productive time.


Funky footwear is essential

  •   Comfortable gear

On a winter retreat, being warm and comfy is a must so wear your warmest, most comfortable clothes.



  • Don’t forget down-time

Having time away from the computer is just as important as time at the keyboard. There are some wonderful walks in the Waitakere Ranges so walking shoes are a must out here. It’s pretty muddy at this time of year so cleaning shoes and sticking to tracks is essential to avoid spreading kauri dieback but getting out in the bush or on the beach is a great way to prepare for the day or take a break from it all.


Good food helps power brains

  • A writing retreat doesn’t have to be away from the office

Continuing momentum is easy with virtual writing retreats. Try Shut up and Write Tuesdays for an online community and some great writing tips.


Close to the fire is always a popular spot on a winter retreat


Other useful resources

Stephen Heard’s The Scientist’s Guide to Writing is a great read for postgraduate students and early career researchers across many fields. It is a comprehensive guide to the structure, content and style of scientific writing. My only criticism is that there was very little said about writing abstracts.

Duke Graduate School Scientific Writing Resource has writing lessons and exercises to improve writing.

For the academics of writing, the University of Auckland’s writing website has a blog, projects and events.

Happy writing!

Dr Cate Macinnis-Ng is a Senior Lecturer and Rutherford Discovery Fellow, School of Biological Sciences, University of Auckland.  She is a plant ecophysiologist and ecohydrologist working on plant-climate interactions.




If a tree falls in the forest, and no one hears it…

The demise of long-term population monitoring

Posted by Margaret Stanley @mc_stanley1

“Is there any evidence that an introduced insect – other than a social insect – has caused the decline of a native species in New Zealand?”

A feeling of total frustration and helplessness came over me when I heard those words – while standing before an EPA panel deciding whether to allow a generalist insect predator into New Zealand for biocontrol of a crop pest.

The answer to this is “no”. The frustration comes from the fact that we have no evidence, because there is no long-term monitoring of native insect populations in New Zealand. The Dept. of Conservation (DoC) may have data for a few threatened species (perhaps wetapunga?), but not for common insect species – those that might follow the fate of the passenger pigeon if an additional invasive predator is the thing that tips the balance for that population. The example I gave the EPA in answer to that question was anecdotal – the decline of our native mantis as a result of the invasive South African mantis. There’s certainly no long-term population monitoring that has picked up the demise of the native mantis.

The lack of long-term monitoring for non-charismatic species (e.g. bees) has also been lamented in Europe lately, where a massive decline of insects in Germany over the last few decades has been detected by the Krefeld Entomological Society: a group of mostly amateur entomologists, recording insects since 1905. They have recorded declines of up to 80% since the early 1980s – that’s a lot of bird food (if you care only for vertebrates!).

biodviersity weather station

Plans for long-term biodiversity monitoring in Germany (Vogel 2007)

Changes in science funding over the last few decades, and the vagaries of politics, means that long-term population monitoring is no longer ‘sexy’ and not worthy of funding (‘Cinderella Science’: unloved and underpaid). These types of datasets are difficult to maintain because they exceed cycles of funding and government administration. In New Zealand we now lament the loss of amazing datasets that have provided the foundation and impetus for some amazing science around ecology, conservation and pest control: e.g. the Orongorongo Valley dataset, and the long term monitoring of wasps, pests and birds in Nelson.

beech seed

Seedfall of hinau and hard beech trees in the Orongorongo Valley 1968-1991 (Fitzgerald & Gibb 2001)

DoC and some councils do undertake regular biodiversity monitoring where they can, but on a reduced number of taxa (usually birds and vegetation), not often at a population level (except for threatened species), and the data are often held within these organisations, rather than open access sites. Some scientists also try to sneak in a long-term monitoring project where their (often unfunded) time and resources allow.

Instead, community groups in New Zealand, those groups undertaking pest control and restoring ecosystems, are taking up the slack in long-term ecological monitoring. At least for vegetation and birds, they are the ones undertaking regular and long-term monitoring via vegetation plots and bird counts. There is also the rise of citizen science – with large numbers of people recording biodiversity: counting kereru and garden birds. Although scientists are doing what they can to give community groups technical advice, and make citizen science more robust, will the data being collected be robust enough to understand how disturbance, invasion, and climate change are affecting biodiversity? Community restoration often takes place primarily where people are (close to urban centres), and restoration projects are dominated by lowland coastal forest ecosystems. Hardly representative of New Zealand’s ecosystems.

Needless to say, there was great excitement within the ecological/entomological community with the initiation of NZ’s National Science Challenges. The idea was mooted that we could have a Long Term Ecological Research network (LETR) like that funded by the National Science Foundation (NSF) in the USA. This network of sites provides the research platforms and long-term datasets necessary to document and analyse environmental change. There are numerous papers that summarise the benefits of long-term ecological datasets, such as: (1) quantifying and understanding how ecosystems respond to change; (2) understanding complex ecosystem processes that occur over long time periods; (3) providing core ecological data to develop, parameterise and validate theoretical and simulation models; (4) acting as platforms for collaborative, transdisciplinary research; and (5) providing data and understanding at scales relevant to management (Lindenmayer et al. 2012). Surely gaining an in-depth understanding of New Zealand populations and ecosystems over time would allow us to understand their resilience to the effects of long-term and large-scale drivers like climate change, and even the effects of new invasive species, such as myrtle rust?

However, it was not to be. And although citizen science and community monitoring is valuable in its own right for specific purposes, it doesn’t allow us to respond to the opening salvo.

If an insect goes extinct in the forest, will anyone know?

Postscript: The EPA decided not to allow import of the predatory insect – not so much because the ecological risk was perceived to be particularly high – but the industry benefits were seen as too low relative to the risk.


MargaretDr Margaret Stanley is a Senior Lecturer in Ecology, School of Biological Sciences, University of Auckland and is the programme director of the Masters in Biosecurity and Conservation. Her interests in terrestrial community ecology are diverse, but can be grouped into three main research strands: urban ecology; invasion ecology; and plant-animal interactions.