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!!

A Key Note; connecting children with nature

Posted by Julia Schmack PhD student at the University of Auckland @julia_schmack

Powerful politicians are denying climate change, mega companies are patenting the seeds of our planet, and ecosystems are exploited for cheap resources at horrendous ecological costs. There are a few more things to add to this list which most of us, working in Biological Science, are aware of. By the way, why did you choose Biology? I reckon I became an ecologist because I have always been fascinated by the colors, shapes, sounds, tastes, smells, textures and especially by the stories that nature provides. Growing up, I found that there are a lot of horror stories going on as well, stories about how we treat forests, water, soil and animals. I thought that knowledge must be the key to prevent people from abusing nature. But sometimes this key doesn’t even get you through the gate of people’s minds onto their front lawn.

Open Gates

Fortunately I found plenty of open doors at the kindergartens I worked with for the last 3 years before coming to New Zealand to start my PhD with the Ecology Ngatahi group. I gave courses for teachers on how to create biodiverse organic gardens with wild herbs and flowers as well as forgotten native fruit and vegetable varieties and nesting sites for beneficial animals in a network of 200 kindergartens. It was fun to work with adults and see how they lose their fear of spates, drills and saws.

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But the most rewarding part of my work for the project and as a freelance environmental educator (www.julia-schmack.de) were the days I spent working with children. Most of the groups consisted of children at the age between 4-9 years old. We built nesting boxes for bees, compiled bug beds, dug ponds and planted “snack gardens”. The children’s questions and observations were so fresh and naïve that there was no room for prepared answers. We investigated every single ‘hypotheses’ on what would be the most adequate house for some of our native bees. There are 547 species of native bees in Germany. More than half of them (53%) are endangered due to severe reductions in nesting habitats and a pivotal decrease of their food resource, native plants (Westrich et al., 2011).

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Our global garden

Globally, pollinators are threatened by climate change, the spread of alien species and diseases and land-use intensification (Vanbergen et al., 2013). International studies on the ecological and economical value of pollination highlight our strong dependency on insect pollinators for agricultural food production. Wild pollinators increase and stabilize crop-pollination services and wild bees in particular are known to improve fruit set, quality and commercial value of various crops. But this remarkable ecosystem service provided by wild bees shows severe decreases in many parts of the world under the pressure of agricultural land-use intensification (Potts et al., 2016).

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We All Love Stories

For the kids the most intriguing question was “where do we find the bees?”. Working the answers out along their own question, they elaborated the story of ‘the native bees in need’ and decided to help them. Being a wild bee, they imagined, it must be hard to find a place to nest and stay over winter. They also worked out that there is not much to eat if you only like native plants. Don’t worry, there is evidence that children are interested in and understand complex environmental concepts (Grodzinska-Jurczak et al. 2006; Palmer and Suggate 2004). So here we go! Step by step we replaced the backyard lawn with wild herbs, native flowers and fruiting trees. We built nesting blocks and put up water bowls. When the first native bees colonized the blocks, the garden became a well frequented observation spot as the kids proudly presented their project to their friends and families. They explained the bee’s story to other children and presented a local solution to a global problem.

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Find a short take on native bees colonizing nesting blocks on our Ecology Ngatahi Youtube Channel.

Nature and Health

Chawla et al. (2014) showed that green schoolyards “enable students to escape stress, focus, build competence and form supportive social groups”. The natural areas helped children to develop protective factors for resilience and stress management. The four main reasons for favorable reactions on green schoolyards by children: “being outdoors in fresh air”; “feeling connected to a natural living system”; “successfully caring for living things”; and “having time for quiet self-reflection” (Chawla et al., 2014). Bratman et al. (2015) conducted a study on adults and the impact of nature walks versus urban walks on affect and cognition. They found that a 50 minute nature walk decreased anxiety levels as well as rumination and increased working memory performance in participants. A study on students showed that a 40 minute walk in nature has a buffering effect on chronic stress (Olafsdottir et al. 2016).

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Key studies

These studies underline that outdoor experiences are beneficial for human health. But do nature experiences also influence our behavior towards nature? Could they be a key to open gates and foster ecological awareness? Studies in kindergartens, elementary schools and outdoor camps demonstrate that outdoor experiences and direct interactions with nature during early childhood are linked to a positive attitude toward the environment and a stronger motivation to get involved in nature protection (Elliot et al., 2014, Collado et al., 2013, Bögeholz 2006, Palmberg and Kuru 2000, Chawla 1998).

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My Conclusion

To me, hands on environmental education was a fantastic way to communicate what I would like to pass on to children. I reckon, I just used the same key that was used to open my mind to nature when I was a child. So there must be many more keys out there. Let’s go and pass them on to the next generation!

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Julia Schmack is a PhD student at the Centre for Biodiversity & Biosecurity, School of Biological Sciences, University of Auckland. She is researching the ecology and control of Vespula wasps, supervised by Jacqueline Beggs, Darren Ward and Mandy Barron (Landcare Research).  Her PhD is funded by the Biological Heritage National Science Challenge.

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References

  • Bögeholz S, 2006, Nature Experience and Its Importance for Environmental Knowledge, Values and Action: Recent German Empirical Contributions. Environmental Education Research 12: 65–84.
  • Bratman GN, Daily GC, Levy BJ, Gross JJ, 2015, The benefits of nature experience: Improved affect and cognition. Landscape and Urban Planning 138(2015):41–50
  • Chawla L, 1998, Significant Life Experiences Revisited: A Review of Research on Sources of Environmental Sensitivity. Environmental Education Research 4: 369-382.
  • Chawla et al., 2014, Green schoolyards as havens from stress and resources for resilience in childhood and adolescence. Health & Place 28(2014):1–13.
  • Collado S, Staats H, Corraliza JA, 2013, Experiencing Nature in Children’s Summer Camps: Affective, Cognitive and Behavioral Consequences. Journal of Environmental Psychology 33: 37-44.
  • Eilers EJ, Kremen C, Greenleaf SS, et al., 2011, Contribution of pollinator-mediated crops to nutrients in the human food supply. PLoS ONE 6: e21363.
  • Elliot E, Eycke KT, Chan S, Mueller U, 2014, Taking Kindergartners Outdoors: Documenting Their Explorations and Assessing the Impact on Their Ecological Awareness. Children, Youth and Environments 24(2):102-122.
  • Grodzinska-Jurczak M, Stepska A, Nieszporek K, Bryda G, 2006, Perception of Environmental Problems among Pre-School Children in Poland. International Research in Geographical and Environmental Education 15: 62-76.
  • Palmberg IE, Kuru J, 2000, Outdoor Activities as a Basis for Environmental Responsibility. Journal of Environmental Education 31: 32-36.
  • Palmer JA, Suggate J, 2004, The Development of Children’s Understanding of Distant Places and Environmental Issues: Report of a UK Longitudinal Study of the Development of Ideas between the Ages of 4 and 10 Years. Research Papers in Education 19: 205-237.
  • Vanbergen AJ, the Insect Pollinators Initiative, 2013, Threats to an ecosystem service: pressures on pollinators. Frontiers in Ecology and the Environment 11(5):251–259, doi:10.1890/120126.
  • Westrich P, Frommer U, Mandery K, Riemann H, Ruhnke H, Saure C, & Voith J, 2011, Rote Liste und Gesamtartenliste der Bienen (Hymenoptera, Apidae) Deutschlands. – In: Binot-Hafke M, Balzer S, Becker N, Gruttke H, Haupt H, Hofbauer N, Ludwig G, Matzke-Hajek G & Strauch M (Red.): Rote Liste gefährdeter Tiere, Pflanzen und Pilze Deutschlands. Band 3: Wirbellose Tiere (Teil 1). – Münster (Landwirtschaftsverlag). – Naturschutz und Biologische Vielfalt 70 (3): 373-416.

Using science to help eradicate Argentine ants

Posted by Darren Ward @nzhymenoptera

Effective detection plays an important role in the surveillance and eradication of invasive species. Invasive ants are regarded as very difficult to eradicate and are prone to imperfect detection because of their small size and cryptic nature.

One species, the Argentine ant, Linepithema humile, is highly invasive and has been accidentally introduced by human trade to many countries throughout the world. It has invaded numerous habitats, including coastal sage scrub in southern California, riparian woodland in California, matorral in Chile, fynbos in South Africa, subalpine shrubland in Hawaii, and oak and pine woodland in Portugal. In New Zealand, Argentine ants are known to occupy a range of open-canopy ecosystems, including native habitats and anthropogenic environments.

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One of the key goals of Argentine ant management in New Zealand is the eradication, and prevention of re-establishment, of Argentine ant populations from offshore islands. A major part of this goal is developing surveillance and analytical methods to increase confidence that offshore islands are free of Argentine ants, or that a population has been successfully eradicated.

Our recent research demonstrates the use of two very different science tools to help achieve an outcome. First the use of a detection dog, trained to detect Argentine ant colonies, and secondly the use of spatially explicit surveillance models. Both tools are used to estimate the probability that Argentine ants have been eradicated from an offshore island site, given their absence across four survey periods and three surveillance methods, conducted since ant control was applied.

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Rhys-Jones, the world’s first detection dog for Argentine ants. Trained by Brian Shields at the Auckland Council.

We found the probability of eradication increased sharply as each survey was conducted. Using all surveys and surveillance methods combined, the overall median probability of eradication of Argentine ants was 0.96. Our results demonstrate the value of spatially explicit surveillance models for the likelihood of eradication of Argentine ants. We argue that such models are vital to give confidence in eradication programs, especially from highly valued conservation areas such as offshore islands. The concept is also applicable to other species of invasive ants, and indeed other invasive taxa.

Ward DF, Anderson DP, Barron MC. 2016. Using spatially explicit surveillance models to provide confidence in the eradication of an invasive ant. Scientific Reports. 6:34953. DOI: 10.1038/srep34953

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.

The importance of community involvement in ecological projects – reflections from #ERA2016conf

Posted by Lizzy Lowe @LizyLowe

This week, many of the members of our lab attended the joint conference between the New Zealand Ecological Society and the Society for Ecological Restoration Australia. I’ve attended many ecological conferences, but I’ve never experienced such a strong theme of community involvement. Importantly, many of the talks I attended expressed the need not just to do public outreach (which can suggest leaning down from our ivory tower to educate the masses) but to involve the community in the science, decision making and evaluation of ecological research.

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Thanks @SpidermanbryceZ for this community photo!

Many of the key note presentations had an underrunning theme of community involvement. Margaret Lowman told us of her long, successful career, and her experiences getting people of all ages and backgrounds into the tree tops to study canopy ecosystems. She also spoke about using inaturalist as a tool for documenting biodiversity and to encourage people to explore the flora and fauna of their local regions. Our local equivalent it NatureWatchNZWendy Henwood showed us that iwi knowledge and experience is invaluable in the decision making process of restoration projects and talked about the success of iwi lead projects in New Zealand.

Alan Featherstone showed us that one person can have a huge impact on the landscape, even with little to no resources. He gave stunning examples of rewilding the Caledonian forest in Scotland in areas he termed “outdoor museums” (no life but full of dead and preserved natural history). It was inspiring to see the results of years worth of volunteer labour protecting and replanting the Scottish forests. Alan also drew connections between Scotland’s growing political independence and their desire to take back and rewild their natural spaces. I loved this observation because it demonstrates how important a connection with the land and an investment in land management is for a country and its people’s identity.

lizzy-blog2The importance of connections between people and landscapes were also very evident in the key note by Kevin Prime. Kevin gave many examples of important iwi cultural sites and showed how the local people’s connection with the land is integral to the process of restoring New Zealand’s natural environments.

Kingsley Dixon noted that without community involvement in ecological restoration, projects have little hope for success. He gave a depressing example of an innovative restoration project that was planned for a coastal area in Perth (my local beach in fact!) that was vetoed because the public didn’t want to lose the grassed areas for ugly native dune vegetation. This story really resonated with me and has renewed my ambition to get out and make connections with my local community.

These speakers all showed how important it is for people in the community to feel connected with their surroundings. I think that people around the world are feeling disenfranchised with political systems, left out of the decision making process and helpless to prevent the broad scale ecological disasters that are occurring globally. This helplessness can lead to resignation and reduce the initiative to maintain sustainable lifestyles. But being involved in ecological projects leads to empowerment by giving everyone the opportunity to contribute to conservation and to invest in their local ecosystems. This is enormously beneficial both to local communities and to the scientists who receive not only help in conducting the research, but a fresh perspective on tackling environmental problems. This is especially valuable when the indigenous peoples of an area are involved.

Some other highlights for me from this conference were a couple of innovative examples of increasing biodiversity in forgotten urban spaces. Margaret gave the great example of “sneaking in biodiversity” in the verges of new housing developments, and in sports grounds, cycle ways and golf courses. In the open science section Robyn Simcock used her impressive efforts in her garden as an example of how to increase the sustainability of private back gardens. I also really liked Bruce Hill’s presentation on using transport lanes as avenues of biodiversity. Areas such as road sides and corridors for telephone wires have traditionally had little ecological value, but his work in Sweden showed that these spaces can be utilised to support local pollinator communities. As urban space is always going to be at a premium, innovative ideas like this are essential for the maintenance of biodiversity in urban environments.

lizzy-blog4I also want to give a special mention to Josie who won a student award for her presentation on the consequences of feeding bread to birds and the fantastic key note by Jacqueline. The key note covered a broad range of topics including Jacqueline’s own ancestral connections with the land, the impacts of invasive wasps and the responses of native pollinators, and supporting the plight of women with children in science! The lab members also contributed to a moving waiata at the end of the presentation which I think was a marvellous close to the conference.

 

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The student prize winners

The conversations around community involvement at this conference are really important for opening science up to the public, and I think there needs to be much more of this in Ecology. Maybe in addition to our scientific conferences we should be holding frequent open days for our ecological research, to connect with the community and demonstrate how everyone can be involved in improving the health and sustainability of their local ecosystems.

Dr Lizzy Lowe is an urban ecologist and entomologist. She is currently working as an Endeavour Postdoctoral Fellow in the Ecology Ngātahi group.

For more on the conference, see #ERA2016conf on twitter.

Untangling insect respiration

Posted by Jessica Devitt @Colette_Keeha

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Over several millennia insects have developed physiological adaptations to their environments through the process of natural selection.  Thus, insects are one of the most diverse and widespread animal taxa.

Insects have evolved diverse respiratory responses to a wide range of environments. The mechanisms behind these differing responses are not fully understood, with some insects displaying adaptations to low O2 (hypoxic) and high CO2 (hypercarbic) atmospheres. One such adaptation is the so-called Discontinuous Gas Exchange Cycle (DGC) where the insect only releases CO2 to the external environment periodically (Figure 1).

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Figure 1. Graphic showing discontinuous gas exchange phases: The flutter phase (F) where CO2 is released during a rapid opening and shutting of the spiracle, the open phase (O) where a burst of CO2 is released from the spiracle and the closed phase (C) where the spiracle is closed for a time resulting in a small release of CO2 (Hetz & Bradley, 2005, p. 517).

There is debate as to what the main function of this adaptation is: one school of thought suggests DGC might protect against desiccation. The other is that DGC allows insects to withstand hypoxic environments.

This brings us to my study species: The golden-haired bark beetle (GHBB) (Hylurgus liginperda: Curculionidae). Bark beetles predominantly attack damaged trees, stumps and fallen/felled trunks and branches. GHBB adult beetles burrow through the bark creating galleries within the cambium/phloem, in which the eggs are laid. Once the larvae have consumed the available cambium/phloem and undergone pupation, newly emerged adults take flight to the next available resource.

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Figure 2. Hylurgus ligniperda (Fabricius, 1792). (Schmidt, 2014)

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Figure 3. Hylurgus ligniperda adults exposed under pine bark. (Pest Alert, n.d.)

The golden-haired bark beetle is a widespread forest pest distributed throughout several continents, such as Australasia and North and South America. Although the beetle itself does not cause significant damage to the heartwood, its presence on export logs creates a market access issue.

In my PhD study we will investigate the respiratory responses of GHBB to a range of atmospheric conditions, such as contrasting O2/CO2 levels over different durations. I plan to use GHBB as an experimental model to understand bark beetle respiration in the presence of low O2/high COenvironments.  My experiments will manipulate atmospheric conditions with the addition of fumigants in order to ascertain the most effective conditions in which to treat export logs.

References

Hetz, S. K., & Bradley, T. J. (2005). Insects breathe discontinuously to avoid oxygen toxicity. Nature, 433(7025), 516-519. doi:10.1038/nature03106.

Pest Alert. (n.d.). Hylurgus ligniperda adults exposed under pine bark.  Retrieved from http://www.pestalert.org/espanol/PhotoDetail.cfm?RecordID=47

Schmidt, U.  2014. Hylurgus ligniperda. Retrieved from https://www.kaefer-der-welt.de/hylurgus_ligniperda.htm

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Jessica Devitt is a PhD student at the Centre for Biodiversity & Biosecurity, School of Biological Sciences, University of Auckland and Plant and Food Research. She is researching the respiratory responses of the golden-haired bark beetle to advance fumigation techniques. She is supervised by Jacqueline Beggs from the University of Auckland, Adriana Najar-Rodriguez and Matthew Hall from Plant and Food Research

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When roles are reversed – all in the name of science!

 

Posted by Hester Williams @HesterW123

As international trade and travel increases, the arrival of non-native species in new territories has accelerated accordingly. Many of these non-natives are unable to establish, while the establishment of others are so successful that they become major economic and ecological threats in their new environments. To prevent the arrival of non-native species, governments across the world impose different measures, e.g. surveillance programs, quarantine measures, inspections, and restrictions on movement of certain goods.

Biological invasions can be separated into a sequence of phases including arrival, establishment, population growth, and spread. The second phase of the invasion process is critical as this is where the establishment of a small founder population occurs, and where the success of eradication is much higher while populations are small. More often than not we don’t get a chance to study newly established insect pests because they go undetected until they are widespread. By that time, eradication can be very difficult.

I have just started my PhD, where I will identify the key factors influencing the establishment (and then eradication) of exotic insect species. However, instead of using exotic species, I will use biological control agents as proxy invasive systems.

A reversal of roles! The biocontrol agent thus becomes the foe, and the invasive plant the friend!

Propagule pressure has emerged as arguably the only consistent factor explaining establishment success, while several intrinsic (‘internal’) processes underpin the effect of propagule pressure, namely demographic stochasticity, Allee effects, and genetic diversity. My studies will focus on the invasive plant, Tradescantia fluminensis, and one of its biocontrol agents, the leaf beetle Neolema ogloblini, and through a combination of field and mesocosm experiments, I aim to identify the role these key processes play in the establishment of the beetle. Heartbreakingly, once beetle populations have been established, I will use methods to eradicate them – techniques that will lower the population level to a critical level (below the Allee threshold where the population will go extinct).

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Tradescantia leaf beetle (Neolema ogloblini) adult

 

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Tradescantia leaf beetle late-instar larva

But all in the name of science! This project will generate a better understanding of the key factors that affect biocontrol agent establishment and also invasion success of invasive pest species. Ultimately it aims to give guidance on what eradication approaches are more or less promising for particular species.

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Hester Williams is a PhD candidate in the School of Biological Sciences, University of Auckland and is stationed with the Landcare Research Biocontrol team in Lincoln, Canterbury. She is interested in invasion processes of both insect and plant species. Hester is supervised by Darren Ward (Landcare Research/University of Auckland) and Eckehard Brockerhoff (Scion), with Mandy Barron (Landcare Research) as advisor. Her studies are supported by a joint Ministry for Primary Industries – University of Auckland scholarship. The project is an integral part of an MBIE program “A Toolkit for the Urban Battlefield” led by Scion.

 

Embracing complexity to address equity

Posted by Cate Macinnis-Ng @LoraxCate

Defining order in complex systems is central to the science of ecology. We use Linnaean classification to sort and name organisms, foodwebs to define flows of matter and energy and population models to describe population dynamics. This need for structure in a complicated world is not unique to ecology. Businesses have an organisational structure, maps help us define the location of geographical features and spreadsheets allow us to organise data. As datasets grow, we need more ways to arrange, store and make use of this information.

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Leaf venation – an exquisite example of complexity in ecology. Image: Wikimedia commons

This week is the annual Rutherford Discovery Fellowship workshop when we all gather at The Royal Society of New Zealand in Wellington. Our guest speaker this year was Dame Anne Salmond on the topic of equity excellence. With a long and distinguished career as an anthropologist (including nine years as the PVC Equal Opportunity at the University of Auckland), Dame Anne is well placed is provide rich insights on equity and diversity.

Central to her talk was the religious hierarchical structure of life and matter known as the Great Chain of Being. This ancient ladder defines the place in the world for all life forms, precious stones, metals and minerals. Each step up the ladder represents greater authority and leadership while those beings on lower rungs should pay tribute to layers above. Civilised people rule over barbarians, men over women and free citizens over slaves. In modern times, we have dismissed much of this mythical model as parochial but Dame Anne argued this structure still has some influence in our lives as the basis of top-down leadership and the reason for the glass ceiling. She also used the examples of resource management and ecosystem services to illustrate human-centred ideas about earth systems.

Holding on to remnants of hierarchical structures is preventing progress in equity in our research institutions and other organisations. Complex networks are far more realistic and effective because they allow diverse voices to be heard. Science is enriched with new and unexpected styles of thought that remain hidden in a hierarchy. Networks of leadership and relationships with the wider community will help to address a range of equity issues. Finally, networks of researchers are needed to address our most pressing problems such as climate change and invasive species. Without effective collaboration between researchers in science, social science and the humanities, solutions will remain elusive.

Seawifs_global_biosphere.jpgGlobal productivity – large-scale complexity in ecology. Image: Wikimedia commons

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.