Save the bees!

Posted by Jamie Stavert @jamiestavert

It seems that everyone loves honeybees and everyone wants to save them. Of course they do. Honeybees give us honey, they pollinate our crops, kids like them, and they’re great for science outreach. But despite their endearing, cuddlesome nature, I have issues with honeybees. Firstly, they’re exotic to New Zealand, some would even say invasive, and they’re probably having negative impacts on our native biodiversity. Secondly, I think they’re crying wolf (at least in New Zealand).

The general public have a terrible misconception about bees; when people think about bees they inherently think of honeybees. That’s it. One bee. Let’s save it, or we’ll all die. In New Zealand, the deluded media continues to wheeze and waffle about honeybees in peril, yet hive numbers have increased from 300,000 in 2000 to 685,000 in 2016. That’s a whopping 120% increase! Meanwhile, native bees continue to go unnoticed and unrecognised.

hive numbers in NZ

Change in the number of registered honeybee hives in New Zealand from 2000-2016. The red dashed line is when Varroa was first detected in New Zealand.

Unfortunately, few people know that there are over 20,000 bee species in the world and most of them don’t live in a colony with a queen. Rather, they live solitary lives and nest in the ground or in plant material. Globally, native bees, in combination with other wild insects, contribute more to crop pollination than honeybees. But unlike honeybees which are managed by humans, native bees are strongly affected by the bad things that humans do (e.g., agriculture, urbanisation, pesticides, climate change and invasive species). In addition, evidence is mounting that honeybees have negative impacts on wild insects, largely through competition.

Leioproctus of Coriander

An endemic New Zealand bee (genus Leioproctus)

I’m not saying that we should forget about honeybees altogether and let Varroa have its way with them. They’re important pollinators of many crops and make manuka honey that cashed up baby boomers pay $1,000/kg for to treat their pinot noir induced acid reflux. But it seems dumb to rely on a single species to do all the pollination. It’s akin to “putting all your eggs in one basket”. Resilience comes in the form of biodiversity. When we have lots of biodiversity we have many species that are equally capable of doing the job. For example, if we have 10 pollinator species that are equally good at pollinating a crop and for some reason five species go extinct, we still have five species left. However, if we have one species and it goes extinct, that’s it, game over.

So how can we save the bees? Our native bees? Essentially they need natural habitat, which provides floral and nesting resources. In New Zealand, native bees are active from September to February and require flowers (preferably natives!) throughout that period. They also require sites for nesting; small holes (2-3 mm) in timber/plant material for cavity nesting species and areas of warm, well drained bare earth for ground nesting species.

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A ground nesting Leioproctus bee emerging from its nest hole

These solutions are feasible on a small scale (i.e., in urban gardens), but the real problem is at a much larger scale, where agricultural intensification threatens to wipe out native bee populations. Therefore, to “save the bees” perhaps we need to move beyond the capitalist dream of monocultures, mono-pollinators and massive profits, and instead vie for diverse production systems that truly value biodiversity.

For an up-to-date assessment on the global status, trends and threats to pollinators and pollination check out: the assessment report of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) on pollinators, pollination and food production.

IMG_0293Jamie Stavert is a PhD candidate at the Centre for Biodiversity &
Biosecurity, School of Biological Sciences, University of Auckland. He is interested in how functional traits influence ecosystem function and species’ responses to environmental change in pollination systems.
 He is supervised by Jacqueline BeggsAnne GaskettDavid Pattemore and Nacho Bartomeus.

International Day of Forests

By Melanie Zacharias @Mel_Zacharias

In our urbanised society people still have a deep relation to forests. A forest is a place to recover from noisy city live, a place to do sports without the smell of a sweaty gym or just an environment to find oneself. Unfortunately, most people do not know about the complex ecosystem services, forests provide worldwide. Carbon storage, water regulation and supply to timber production are only a few of them! Furthermore, even single city trees are proven to have economic and health benefits like filtering fine particles and reducing stress. Nevertheless, the trees of our world are threatened by deforestation, invasive species, soil degradation and of course climate change. We all like our high standard of living; with fancy cars, travelling around the world and exotic food but sometimes we should remember that our own consumer behaviour affects the conditions of forests.

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The Food and Agriculture Organization of the United Nations (FAO) is an intergovernmental organization with 194 member countries to achieve food security for all. The United Nations General Assembly of the FAO proclaimed the 21th of March as the International Day of Forests (IDF) in 2012 to underline the importance of all types of forests and their threats. The versatile services of the forest ecosystems in ecology AND economy lead to the theme of 2017: Forests & Energy, chosen by the Collaborative Partnership on Forests. Whereas saving forests from logging is not only environmental protection, the timber energy sector is an important employer in both, developing and industrialized countries. With the growing demand for wood as aresource for renewable energy, sustainable forest management is at least as important as 300 years ago, when Hans Carl von Carlowitz first described the concept of sustainability in his book Sylvicultura oeconomica (1713).

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If you want to give something back to the forests, join in and plant a tree 🙂 For example on Motutapu Island. There are many activities involving forests and trees around the International Day of Forests or just get out to your favourite local forest for the day and share a picture.

#IntlForestDay or #LoveForests

IMG_2462Melanie Zacharias is an intern in the Centre of Biodiversity and Biosecurity, School of Biological Sciences, University of Auckland supervised by Cate Macinnis-Ng. She recently completed a MSc in forestry at the University of Technology Dresden, Germany.

 

Presence or absence: predicting the probability of population survival

Posted by Lloyd Stringer @lloydstringer2

With it being St Patrick’s day, I thought it appropriate to give you a little overview of one aspect of my research, population growth modelling, with a Paddy’s day theme.

Factoid- Student’s t-test was developed by William Sealy Gosset (publishing under the pseudonym Student) while working as a chemist at Guinness brewery.

Every year about this time, NZ experiences a mass migration of barrels of Guinness that require population management. Luckily, NZ has a biosecurity team of 4.7M people to help deal with this population outbreak (perhaps this isn’t what contributors to the Biosecurity 2025 document had in mind).

Guinness tanker

Developing a population growth model, is a key aspect to developing a management strategy. This isn’t readily available for some modelling targets, but luckily the biology of Guinness is well documented and experienced, so few assumptions are required.

While it does appear in hotels throughout the country for much of the year, it isn’t until we see the migration, that the shear overload causes additional pubs to sprout taps to dispense this nutritious bounty. During non-outbreak periods, population replacement approximately matches mortality. However, we’ve discovered that on March 17, during a peak outbreak time, population density displays exponential growth. It is a wonder that we don’t see masses of migrating Guinness pints moving about the landscape, but we find that nature has a unique way of dealing with the bounty.

lots of guinness poured

During times of plenty, particularly Paddy’s day, natural Guinness niches (pubs) produce music that is heard over a large area, and this brings in Guinness’ natural predator… Homo sapiens. The probability of H. sapiens being attracted to Guinness as a function of distance has been tested for quiet niches. During the Paddy’s day celebration, the number of individuals arriving at niches is 37 times greater than average. It is assumed that this increase in attraction range is due to the sound produced by the various Irish bands and clinking of glasses. Having this larger area of attraction increases the probability of Guinness being consumed, thus the probability of survival is reduced.

Psurvival-music = (1-Pconsumption)×Nconsumers_music/ha

With Nconsumers_music a function of the number of consumers expected to be attracted per ha with the increase in the attractive range of the niche with music over a quiet niche. We find that population growth changes from a predicted λ = 0.04 (without music) to λ = -0.002 (with music). If we start with an initial population of 1000 pints of Guinness, then we are likely to have 16 h before a musical pub runs dry.

drinking guinness

Of course, there will be variation around some of these estimates, especially climatic conditions. Canterbury for example has warm dry conditions predicted. This favours a rapid decline of the population (an additional 5%), further with Paddy’s day occurring on a Friday allowing for a sleep-in the following day, it is expected that the Guinness survival rate (warm and dry + sleep-in) will be 10% lower than λ = -0.002 estimated above to λ = -0.025, so population will be expected to only last ~3h.

By understanding a little about the potential growth rates of a population we can estimate the probability of survival of a population. It appears that for this year at least Guinness population will be managed naturally by the sleep-in, however, if pubs wish to increase the mortality rate the Guinness, increasing the ambient temperature of the pub will reduce Guinness survival rates.

Please note, many data were harmed during the writing of this piece.

Lloyd Stringer is a PhD student at the School of Biological Sciences at the University of Auckland, and scientist in the Biosecurity Group and Plant & Food Research, Lincoln. He is studying the effects of population management tools on insect Allee thresholds. He is supervised by Max Suckling, Jacqueline Beggs, and John Kean

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I should be writing..

Posted by Alice Baranyovits @ABaranyovits

This post is slightly different from my usual efforts, mostly because I’m in the last (although it seems never ending) stages of writing up my thesis and it’s all my brain can think about at the moment.  As I haven’t successfully handed in my thesis yet I’m not sure if I am qualified to give advice but here goes anyway.

  1. Start writing early – this is the one that everyone tells you to do and they’re right. I remember very clearly at the start of my PhD thinking that I was definitely going to do this and I would be done with the writing at least a few months before my final deadline, giving me plenty of time for the final  edits and formatting etc. This has not happened. Whilst I had done my literature review and first chapter fairly early on, I wish I had done more.  So keep writing throughout, your future self will thank you.
  2. Find a method that works well for you – I use the Pomodoro technique; you can find out more about it here. I’ve also found that for me, when I’m just writing I work best at home (its quiet, I can sit out on the deck and there are plenty of snacks close at hand – see point 7). But I know many people that prefer writing at cafes or in the office – just find what works for you.
  3. Make sure you take proper breaks, even if it’s just for a few hours outside for a walk (getting out into nature also has many mental-health benefits), but preferably for at least a whole day now and again. I wish I had done more of this over the last few months because the occasions when I have had some time away from the thesis I am always much more productive when I get back to it. Just try and ignore the ‘I should be writing’ thoughts.

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    Going for a walk outside can help reduce your writing induced stress

  4. Accept that some days aren’t going to be as productive as others & everything takes longer than you expect.
  5. Don’t worry to much about getting everything word prefect in you’re first draft.
  6. Take it one task at a time – there have been a few times in the last couple of weeks where I have been pretty overwhelmed with everything I have left to do (obviously if you have followed point number one you won’t have this problem). This is where I have found taking a break (go outside for that walk) and just planning what I need to get done that day or over the next couple of days and focussing on that, to be really helpful. Having smaller deadlines can help too.
  7. Snacks – never underestimate the importance of good snacks. Or tea.
  8. Stop procrastating & get back to work!

There is plenty of useful information out there from people who have actually successfully finished their thesis’, there are a few links below & feel free to leave some tips in the comments.

https://www.theguardian.com/higher-education-network/blog/2014/aug/27/finishing-phd-thesis-top-tips-experts-advice

https://thesiswhisperer.com/category/on-writing/

http://www.nextscientist.com/habits-reclaim-life-writing-dissertation/

http://www.nextscientist.com/writers-block-phd-students/

Anyhoo, I better get back to it – wish me luck.

Alice BABaranyovits is a PhD student at the School of Biological Sciences, University of Auckland. She is researching kererū (NZ pigeon; Hemiphaga novaeseelandiae) in urban areas. She is supervised by Jacqueline Beggs, Mick Clout, Todd Dennis & George Perry.

Getting out and about

Posted by Anna Probert @afprobert

From effects of artificial light on wildlife to sexual selection and weaponry of spiders and stress responses of seabirds, there is some really neat research being produced by students within our wider lab group.

In my opinion, one of the best things about being a PhD student is engaging with scientists conducting interesting research outside of my own field, and in some cases, having the opportunity to tag along and help them in the field. I had this pleasure last month, when I went down to Pureora Forest Park, where PhD student Kat Collier is researching the New Zealand lesser short-tailed bat Mystacina tuberculata

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The opportunity to get up close and personal with a native New Zealand mammal is zen-kat-radiosomething that not many people, let alone many other scientists, often have the opportunity of doing. And whilst I had an enjoyable time out in the forest (which makes a nice change from the open scrub ecosystems I work in for my ant research), I also came back with some new skills and understanding of different ecological methods, such as radio-tracking and harp and mist netting for bats.

team-bat

Going out into the field with other researchers is a great way to provide what is often much needed field assistance and support, as well as broaden your own personal skill set, which you may not have the opportunity to do within the limits of your own research. It’s also a great way to realise what you don’t like.

Overall, I think it helps to make you a more rounded ecologist and is a great excuse to get out the office and have a break from your own research.

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Anna Probert is a PhD student in the Centre for Biodiversity & Biosecurity, School of Biological Sciences, University of Auckland. She is using ants as a model to assess the risk posed by exotic invertebrates to native ecosystems. She is supervised by Margaret Stanley, Jacqueline Beggs, and Darren Ward.

Tribute to the fallen: urban trees

Posted by Ellery McNaughton @EJ_McNaughton

Every month for the past 15 months I have stood on the streets at my study sites and conducted 10-minute bird counts. Somewhere along the line, I inadvertently began counting trees. Every site has at least one tree that birds seem to favour perching in over others, a sort of bird-version of the cushy chairs that granddads can always be found in. I often find myself focussing on these trees during my bird counts (while also not forgetting the other, less favoured bird-versions of church pews and university-seminar chairs). It makes it particularly noticeable when I turn up for the next month’s count, and that tree is gone.

tree-stump-1

Of my 27 sites, 14 of them have had at least one tree cut down in the past year. Some were natives. Some were over 10 metres tall. Sometimes they were replaced with other trees. Sometimes they were replaced with houses. Mostly they weren’t replaced with anything.

Urban trees are at risk. In places like central Auckland, where the majority of urban tree cover is on private land, it is important to have policies in place that can be used to protect and maintain the urban forest. Unfortunately, governmental policy reforms meant that in 2015 blanket urban tree protection was removed in Auckland, leaving an inadequate individual-based tree protection policy behind. With the exception of registered ‘notable’ trees and those in certain ecological areas, homeowners have free rein with regards to chopping down trees on their property.

Yes, a man’s home is his castle. The problem is, we live in a community of castles. Trees provide communal benefits. They increase health, mental wellbeing and air quality. They create additional opportunities for connection with nature by providing habitat to urban wildlife. People need to start looking past the boundaries of their property and their present time. When decades of growth can be cut down in minutes, the least one can do is consider the bigger picture. If nothing else, at least consider that it is jolly difficult to conduct a bird count over the noise of a chainsaw.

Ellery (2)Ellery McNaughton is a PhD student in the Centre of Biodiversity and Biosecurity, School of Biological Sciences, University of Auckland. Her project investigates the effects of a city-wide changeover in streetlight technology on urban bird behaviour and ecosystem function. She is supervised by Margaret Stanley, Jacqueline Beggs, Kevin Gaston(University of Exeter, UK) and Darryl Jones (Griffith University, Australia).

Kauri and drought – What’s their survival strategy?

Posted by Julia Kaplick @julekap

New Zealand’s future climate is likely to be warmer and dryer and the frequency and duration of drought events is predicted to increase. Drought-induced tree mortality is increasing world-wide, with several instances also reported in New Zealand. So far we know very little about the drought vulnerability of New Zealand forest trees, but due to our research on kauri we are beginning to understand more and more about the drought survival strategy of this forest giant.

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Roots

The roots are integral for trees to extract water from the soil and a good root network is crucial for drought survival. During times of water stress many trees, including kauri, invest in root growth. This allows them to keep up their normal transpiration levels for a little longer. So far it is assumed that kauri roots are very shallow, but sap flow measurements during the 2013 drought suggest otherwise. The upper soil layer during that time was extremely dry, but the trees still used water which suggests that kauri roots must reach a lot deeper than we previously thought allowing access to deeper water stores.

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Kauri roots

Drought avoidance or toleration?

In general, every tree species falls somewhere on the spectrum between drought avoidance and drought toleration. Drought tolerating trees keep up transpiration as long as possible. Drought avoiding species on the other hand start closing their stomata to reduce water loss, when the soil moisture goes down. Both strategies have their downsides. Drought tolerators risk the formation of little air bubbles (xylem embolism) in their conducting tissue. This can lead to hydraulic failure if a drought lasts too long. Drought avoiders protect their hydraulic integrity but risk starvation, because the closure of the stomata also means a reduction of carbon intake. Kauri are clearly drought avoiders. Even under ideal growing conditions kauri are conservative water users, closing their stomata early in the day. They are known to be very susceptible to xylem embolism and protect their hydraulic integrity in that way.

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Kauri cone in a bed of leaf litter

Leaf shedding

During the 2013 drought the kauri in our study plot lost a substantial amount of leaves and twigs. The reduction of leaf area is an effective way to reduce the water-losing surface and consequently the reduction of transpiration and the need for water uptake.

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Base of a kauri stem

Water storage

All components of a tree (roots, stem, branches, leaves) can serve as water storage compartments. This is a drought survival strategy that succulents have perfected. Kauri make use of stored water on daily basis. Water is withdrawn from the stem and branches in the morning when the water starts to transpire from the leaves. During the afternoon and night these stores are refilled again. The massive stem volume paired with deep sapwood seem to make a great water store. During prolonged drought conditions kauri should be able to use the water reserves to their advantage. This is something we are investigation right now, stay tuned.

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Julia Kaplick is a PhD student in the Centre of Biodiversity and Biosecurity, School of Biological Sciences, University of Auckland. She is researching the response of native trees to seasonal variation in climatic conditions using measurements of sap flow, water relations and carbon allocation. Julia is supervised by Cate Macinnis-Ng (University of Auckland) and Mike Clearwater (Waikato University). Julia is supported by funding from the Marsden Fund.  

Thanks, volunteers!

Posted by Carolina Lara @carislaris

A quick summary of some of the amazing things achieved in the second year of my PhD: leaf samples of 350 trees collected, processed and stored at -80˚C, 500 hours of birds´ visitations to New Zealand native plants video recordings analysed and 162 hours in the field mistnetting – 232 birds so far. If you think I have done it myself, you´re wrong. Throughout this PhD-year I have worked with great volunteers who have helped me achieved all these things. A special mention to Manon Pulliat, our French intern from Agrocampus Ouest, who spent five months at the Centre of Biodiversity and Biosecurity getting to know how scientific research is conducted in other parts of the world.

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Manon after a hard day in the field collecting leaf samples

All of those whose PhD projects involve some sort of fieldwork will agree with me on this: WE NEED VOLUNTEERS. A volunteer is defined as a person who is willing to provide a service without expecting any sort of monetary compensation (quite important if your project is money-limited). They can be classified in three types: 1) casual volunteers whose activity targets specific needs, 2) volunteers who perform more formal types of volunteer service – having a personal commitment and gaining a sense of accomplishment, and 3) volunteers who are required to volunteer by a specific organization. More specifically in the ecology field, there is a relatively new term to refer to those volunteers who participate as field assistants gathering information in scientific studies: “citizen scientists”. Citizen scientists are not necessarily directly involved in the scientific community, some of them are members of the public with a strong desire to understand ecological processes and most importantly, to connect with nature.carola

No volunteer can resist holding a bird while mist netting

Our job as scientists is to provide volunteers with the necessary tools to collect reliable data in the field. This takes time but the end-product will be definitely worth it. Thanks, volunteers for all the help and good moments in the field!

 

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Carolina Lara M. is a PhD Candidate within the Centre for Biodiversity and Biosecurity, School of Biological Sciences, University of Auckland. Her research interests focus on seed dispersal networks within fragmented landscapes. She is supervised by Margaret Stanley,Jason Tylianakis, Karine David, and Anna Santure.

An Ode To Possums and other Pests

Posted by Robert Vennell @RobertVennell

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Conservation in New Zealand often involves killing things. Especially cute and fluffy things, like bunnies, mice, hedgehogs, ferrets and possums. We’ve got a good reason for it – these creatures are decimating our native ecosystems and wildlife and would cause untold destruction if left unchecked. But our obsession with killing things sometimes boggles overseas observers who struggle to understand why we would dress up dead possums in wedding gowns and bikinis.  Come to think of it, I struggle to understand that one as well.

Growing up in New Zealand I think it can be really easy to hate our introduced mammals for all the damage they cause. But its nice from time to time to reflect on how neat these creatures really are. They are incredibly intelligent, curious and fascinating little beasties – It’s just a shame they are in the wrong place and need to go.

One of the things I’ve really enjoyed about using camera-traps for my research – is getting to observe all sorts of cryptic creatures and behaviours that we rarely get a chance to see.

For example, if you head along to the Ecology Ngatahi Youtube Channel you can check out this great video of a playful possum getting up to all sorts of mischief. The final image is a rat falling out of the tree – perhaps it was pushed? Or how about this somewhat spooky montage of rats scuttling up a tree at rapid speed.

The nature of conservation in New Zealand means that to protect our native species from extinction, we have to remove the invasive ones – but that doesn’t mean we can’t appreciate these pests for being amazing little critters in their own right.

 

Robert VennellRobert Vennell is an MSc student in the Centre of Biodiversity and Biosecurity, University of Auckland studying the impacts of wild pigs on native forests. He is supervised by Margaret Stanley, Mark Mitchell (Hawkes Bay Regional Council),Cheryl Krull (AUT) and Al Glen (Landcare Research). He also writes about the history, meaning and significance of New Zealand’s native tree species at www.meaningoftrees.com

 

 

The importance of CWD for Insect Diversity

Posted by Darren Ward @nzhymenoptera

Trees are mostly made of woody stuff. Sometimes this stuff breaks and falls on the ground. It’s called coarse woody debris (CWD).

CWD is considered a ‘wasted’ resource if it just lies around in a forest. Not so! Overseas, the role of CWD has often been heavily studied for its role in restoration, succession, nutrient recycling, and in maintaining the diversity of invertebrates, fungi, et al. But this appears not to be the case for New Zealand, at least from an entomological perspective.

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Good use of CWD

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Less good use of CWD

 

Some of our recent work had highlighted the entomological importance of CWD in forests in the Waitakere Ranges. Our broad aim has been to examine the abiotic factors affecting the diversity of invertebrates, and more specifically different groups of wasps, both native and exotic species.

In each of the studies completed so far, CWD has been a key factor in influencing insect diversity, both the number of species, and the functional diversity of communities.

For example, the abundance of parasitoid wasps in the subfamily Cryptinae, who predominantly attack wood-boring insects (e.g. the larvae of beetles, caterpillars), were positively associated with total CWD volume; while parasitoids that predominantly attack larvae on exposed surfaces such as leaves were negatively related to CWD volumes. Our results also suggest many parasitoid species (and their hosts) utilise small sized pieces of dead wood, indicating the importance of having a range of resources in an environment.

CWD also affects the community structure of spider-hunting wasps (Pompilidae), where greater CWD volume facilitates greater species richness; and specialist deadwood species are only present in areas with higher volumes of CWD.

However, CWD not only influences native insect communities. It also plays a role in regulating the density of an exotic wasp, Meteorus pulchricornis. Here, densities of this parasitoid declined with increasing coarse woody debris, suggesting some type biotic resistance mechanism where Meteorus pulchricornis is less able to invade native forests.

So CWD, it’s cool. Keep it. For the bugs.

Darren Ward is an entomologist in the New Zealand Arthropod Collection at Landcare Research, and a senior lecturer at the School of Biological Sciences, University of Auckland.

Kendall L, Ward DF. 2016. Habitat determinants of the taxonomic and functional diversity of parasitoid wasps. Biodiversity & Conservation. 25(10), 1955-1972i

Kendall L, Ward DF. The role of habitat variability in determining community structure of spider-hunting wasps (Hymenoptera: Pompilidae). Submitted!

 McGrath Z. 2017. Quantifying the ecological risk of exotic species–a case study using the parasitoid Meteorus pulchricornis. MSc Thesis, University of Auckland. Almost submitted!!