30 December 2013

A risky business: predicting invasive species

In which we talk about identifying risk of pest species in light of climate change.

Consider these events: a violent home invasion, a major earthquake, and being hit by a ball on a cricket boundary. Which of these are you most at risk from? Obviously this may depend a little on who you are and where you are reading this. Currently, I am sitting at the Ashburton Oval watching my middle son trial for the Under 17 Canterbury cricket team. I am sitting on the boundary at backward of square or cover ( depending on the end being bowled from). I feel like I could be hit by a ball. I have been through a major quake (well several I guess) so that seems like a reasonable level of risk too. I haven't had a home invasion myself but my auntie in a very quiet village in the Catlins was attacked and beaten last week. So that seems like something that could happen too. How to calculate the relative risks? In all of my years of cricket and cricket coaching, I have never been hit by the ball unless I was trying to stop it (although my car window was smashed on the boundary last year). Although I have been through the Canterbury quakes there is no real predicting if there will be another large one in this area anytime soon. Until last week I had never personally known anyone to be attacked in their home. Having a close family member attacked shouldn't change my odds in any way. In order to sort this out I would need to collect data on rates of criminal activity in an area, plate boundary structure and how attentive people are to watching the bowling at cricket. In short, this is a difficult activity for our brains to work through and humans are notoriously bad at assessing risk. This is why we need models and computers to help us out.

Calculating risk....

One area of economic importance where risk needs to be clearly identified is with invasive species. Invasive species are a side effect of economic globalization. As products and people move around the globe there is always an opportunity for unwanted species to go with them. The wrong species establishing in the wrong place can create huge problems, from causing problems for domestic agricultural industries and lowering production to triggering quarantine restrictions for other countries. At Lincoln University we have the Bio-Protection Research Centre that focuses entirely on issues with invasive species. One of the areas of growth is in predicting areas that might be at a higher risk from invasion. (Woah! Almost hit by a ball! Must remember to look up from my iPad more often) Complicating  things are issues of climate change. If areas closer to the poles are getting warmer then they are at greater risk from species currently living closer to the equator.

Sue Worner from Lincoln, is part of the International Pest Risk Mapping Workgroup, a bunch of like-minded individuals who meet regularly to improve methods of estimating risks posed by invasive species. They have recently put together a special issue in the journal NeoBiota to showcase their findings. Sue is one of the authors of the summary paper that looks at progress in this area. In their introduction article they summaries major findings in pest risk science and: policy (understanding what information is critical in the time available for decisions), climate change (building better scenarios for local change), economics (better estimating the rate of spread of pest species through time), surveillance (developing pest risk maps) and uncertainty ( which arises from a fundamental lack of knowledge about sources of risk). The paper by Sue and her colleagues summarizes these issues and the papers in this issue attempt to develop solutions to these issues and get better at analyzing risk.

So are we better at assessing risk because of these models? It seems so. Models are getting more sophisticated and information is more detailed. There is definitely a sense of progress. It probably doesn't help with my original problem so I might just finish up and keep a better eye on the batsman!

18 December 2013

A lousy chat about the Chathams

As a lecturer you spend a lot of time talking to people. With a bit of practice most lecturers can easily fill 50 minutes with facts, figures and opinions. I enjoy talking to students (and enjoy it more when they talk back!). One thing that is a little novel is being interviewed. David Fisher is collecting interviews from staff at Lincoln University and putting them up on a website. David basically guides the conversation along in an attempt to find out about the research that is done at Lincoln University.

David interviewed me on Monday and I gushed forth for about 50 minutes. The interview is available here to listen to or download (click on Adrian Paterson research). David starts by asking how I ended up having a louse named after me (Myrsidea patersoni). My answer takes me back to my PhD days when I started researching feather lice on seabirds and then leads through to research on the Chathams that looked at the age and origin of its plants and animals. We also discuss the drowning of New Zealand before moving into better ways to count and kill pest species like possums.

Sitting on the Chathams ready to chat!

The scary thing is that when I say at the end "But I've only just started", I am actually stating the truth. I've had over 60 post grads and many colleagues to do science with over the last 20 years and there are lots of interesting research projects I never got anywhere near touching. I guess that is one of the reasons that I helped to start this blog as so much interesting stuff is down around this department that does not get out to the public eye. Anyway, if you want to hear more from me, have a listen.



11 December 2013

How many birds are killed on NZ roads each year?

At last month's EcoTas13 conference, the joint annual conferences of the New Zealand and Australian Ecological Societies, I presented some preliminary calculations of the number of birds killed on New Zealand roads. I've been counting road kill on my bike to work from Christchurch to Lincoln since 2003 so I now have a fairly good idea of how many birds are being killed in this landscape. The rates of birds killed on these roads are similar to statistics from European and North American countries. Extrapolating these out to New Zealand's road network of highways and rural roads suggests that around a million birds could be killed each year.

This is much less than the estimated numbers of birds killed each year by mammalian predators throughout the country, but much larger than the numbers of birds killed by the likes of wind farms or the Rena oil spill.

Of course, most of the birds killed are exotic species, like blackbirds and house sparrows, since these dominate in and around our towns and cities where most roads and traffic are. Still, native birds appear to be equally vulnerable. This additional source of mortality may be having an impact on native bird species in these habitats which are already struggling to persist in suboptimal and fragmented habitats and with abundant predators. A more detailed analysis of my data will be needed to assess that.

You can read the details over on my blog.

road kill fantail
A fantail killed on a busy 80 km/hr stretch of Sparks Road near Halswell, Christchurch (see the associated observation on NatureWatch NZ).