Posted by Darren Ward @nzhymenoptera

New Zealand is well known for its problems with exotic pests and weeds; whether it’s vertebrate predators and their devastating impacts on native birds, vertebrate herbivores chomping through tonnes of native vegetation per night, or weeds out-competing and smothering native species. Relatively speaking we have excellent information on the number of these exotic species, their distributions, densities, and impacts.

But what about exotic invertebrates? How many are there in New Zealand? Apart from a relatively small number of high profile species, the total number of exotic invertebrates species established here is only a ‘best guess’. However, generating such information is an important part of studying invasion biology, particularly when such information is compared and contrasted with other parts of the world.

Hymenoptera are a massively diverse Order of insects, including bees, ants, wasps, and parasitoids. Humans have a love/hate relationship with Hymenoptera. They can be pollinators of economically important crops and of native plants, and have widespread application as biological control agents for the control of insect pests. However, when they are bad, they are horrid. Invasive ants, social wasps, sawflies, woodwasps, and gall wasps, all cause huge economic, social, and environmental problems in different places around the world.

Asian Paper wasp on nest in Auckland.

Recently, we completed the first inventory of all exotic Hymenoptera in New Zealand, and made comparisons to a large European database (DAISIE, Delivering Alien Invasive Species Inventories for Europe).  We found several interesting trends.

• Over 300 species are established in New Zealand, more than in Europe (334 vs 286). The European fauna also had a much higher proportion of intentional releases (i.e. biocontrol, pollination), further highlighting the large number of unintentional establishments for New Zealand.
• Also strikingly was the ‘disharmonic island’ nature of New Zealand. One third of the taxonomic families in New Zealand have no native species, and are only present as exotic representatives, including common taxa such as honeybees, bumblebees (Apidae), and social wasps (Vespidae).
• We also found a change in the origins of exotic species establishing over time, with an increasing dominance of species from Australia during the past 25 years.

Our project shows the importance of examining large-scale datasets of multiple species over long-periods. It also shows the importance of scientific collections – where much of this information was obtained.

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. More detail: Ward DF, Edney-Browne E. 2015. Poles apart: comparing trends of alien Hymenoptera in New Zealand with Europe (DAISIE). Plos One. 10.1371/journal.pone.0132264

Posted by Alice Baranyovits @ABaranyovits

Last week the Royal Society of New Zealand launched their report on options for climate change mitigation for New Zealand entitled ‘Transition to a Low-Carbon Economy for New Zealand’. As part of the launch they released several infographics including a panel on what immediate actions individuals can make to reduce their carbon footprint. These included increased use of public transport and cycling, planting trees, using energy efficient appliances and reducing the frequency of air travel. Whilst these are all important and worthwhile actions, I feel that there is one obvious oversight, one big elephant, or more accurately in this case, cow in the room and that’s that there is no mention on this infographic for the need to reduce meat and dairy consumption.

Now in order to be fully transparent…I’ll admit I’m a vegan and as my friends and family will attest, for someone who doesn’t eat any meat or dairy I do seem to spend quite some time talking about it. But while I’ll try to avoid climbing onto the soapbox for this one, I do feel that meat consumption is something that needs to and should be discussed.

New Zealanders it seems, like their meat. NZ is often listed as one of the most carnivorous countries in the world, with annual meat consumption frequently quoted as being greater than 100 kg per person (with one estimate at a super-sized 126 kg), putting it well above the global average of 42 kg per year – according to this chart from the Economist, New Zealanders are the 4^th biggest meat consumers in the world!

Like many other developed countries, New Zealand’s meat consumption has remained fairly steady and is predicted to remain at similar levels for the coming decades. Globally however, it’s a different story. The demand for meat is growing, linked with increasing wealth and urbanisation of many developing countries. This increase in demand combined with rapid human population growth has seen meat production grow from around 70 million tonnes in 1961 to a huge 278 million tonnes in 2009, with further increases up to a whopping 460 million tonnes predicted by 2050. Now that is a lot of meat.

The stated contribution of livestock production to current global greenhouse gas (GHG) emissions varies from around 10 to 25% (depending on whether emissions due to deforestation and land use change associated with pasture creation are included). But the regularly quoted FAO’s statistic of 14.5%, would put livestock production on par with the emissions contributed by the global transport sector. In NZ, agriculture contributors almost half (47% in 2010) of the country’s GHG emissions, 95% of which come from the pastoral system. On top of this, livestock production has various other substantial environmental impacts, such as high water use, groundwater contamination and biodiversity loss (summarised nicely here).

Ways to mitigate these GHGs are often described in two parts; reducing emissions during production (see here for more examples) and reducing demand. The Royal Society’s report contains multiple potential technical options that could be used to help reduce production related emissions, such as increasing farm efficiency, developing methane inhibitors and selectively breeding lower-emission animals.  However, although these technologies may decrease emission intensity, they are unlikely to limit overall emissions if total production continues to grow.

So how about reducing demand? A global shift to a more plant-based diet, much lower in animal protein than the current average diet in developed countries, has been repeatedly suggested by the UN and others, as one practical way to tackle not only GHGs, but other environmental issues associated with human food production (see the end of the post for some links). For example, in their Fifth Assessment Report the IPCC stated that global dietary change could have a substantial impact on agriculture’s GHG emissions, with a potential saving of 0.7-7.3Gt CO₂-eq/yr in 2050. Additionally, a recent study by Springmann et al. (2016) reported that a global move towards a low-meat diet, which limited red meat intake to 300g a week, would reduce the predicted 2050 food-related emissions by 29%. If people went further and shifted to a fully vegetarian or vegan diet then they predicted that the food-related emissions would be decreased by 63 and 70% respectively.

Now I’m certainly not suggesting that everyone goes vegan, I understand and appreciate that there are many people that rely on the meat and dairy industry for their livelihoods, as well as the fact that many people simply enjoy eating burgers, sausages and cheese. But this isn’t about stopping eating meat but rather reducing how much and what type (beef, for example produces more emissions per kg of protein than poultry).

And yes I know that New Zealand exports much of the meat (83% of beef) and dairy (95%) it produces, so a reduction in domestic demand in New Zealand will have less impact than in a country that consumes most of its own meat. However, that doesn’t mean that we shouldn’t act.  Changing your diet isn’t going to ‘solve’ climate change, but it is one of the easiest ways individuals can help reduce their own environmental impact.   It’s time to start talking about the cow in the room.  So, anyone for a veggie burger?

Further Reading:

• Royal Society of New Zealand (2016) Transition to a low-carbon economy for New Zealand
• Food and Agriculture Organization of the United Nations (FAO). Tackling climate change through livestock – A global assessment of emissions and mitigation opportunities.
• Chatham House Report – Livestock – Climate Change’s Forgotten Sector
• Chatham House Report – Changing Climate, Changing Diets: Pathways to Lower Meat Consumption
• UNEP (2010) Assessing the Environmental Impacts of Consumption and Production: Priority Products and Materials
• UNEP (2012) Growing greenhouse gas emissions due to meat production
• Tilman & Clark (2014) Global diets link environmental sustainability and human health
• New Zealand Agricultural Greenhouse Gas Research Centre Factsheet – The Impact of Livestock Agriculture on Climate Change
• The Guardian – UN says eat less meat to curb global warming
• Meat Atlas – Facts and figures about the animals we eat

Alice Baranyovits is a PhD student at the Centre of Biodiversity and Biosecurity, School of Biological Sciences, University of Auckland. She is researching the movements of kererū in urban areas. She is supervised by Jacqueline Beggs, Mick Clout, Todd Dennis & George Perry.