Bookish memories and New Zealand’s toxic trends

As I turned 16 I started to record the books that I read. Why? I’m not sure. Maybe the budding scientist just collecting data?  Anyway, I have an uninterrupted record running for 34 years cataloguing each book I have read, its author, page length, day of completion and my rating. As of August 1st 2017 this was 1236 books, 412358 pages, and an average rating of 7.4/10. As most ecologists and evolutionary biologists know, a long-term data set, even of relatively trivial recordings can start to recover some interesting facts.

Books are data too! Image by Adrian Paterson.

In some ways this can work as a bit of a diary for me through life’s good and bad times. The days that my sons were born I was reading Heart of Darkness by Joseph Conrad (and given my wife almost died during delivery this might have been almost too appropriate), Startide Rising by David Brin and The Black Unicorn by Tanith Lee, respectively. On September 11th I was reading The Order War by L.E. Modest Jnr. The day Princess Di died it was The Dreamquest of Unknown Kadath by H.P. Lovecraft. During the two big Canterbury quakes it was Shakespeare by Bill Bryson and The Wine Dark Sea by Patrick O’Brian.

The main value of long-term data sets, however, is in uncovering trends. Looking at data over time transforms one-off anecdotal observations into something much more useful and powerful. Trends are usually subtle changes to detect. You need either a lot of data or a long period of time to identify them. Like three decades.

Over those 34 years I read a mean of 36 book each year. However, life often got in the way. Meeting my future wife resulted in some lean initial years resulting in a 40% reduction in books read (obviously a lot of effort went into mate displays, attentiveness and guarding). The early, busy years after the birth of my three sons reduced my mean 12000 pages per year to around 8-9000 (the high cost of brood maintenance). As my sons got old enough for me to read chapter books to them, I recouped with an increase of around 50% over the average for a few years.

The chapter books that I read to my eldest son. Image by Adrian Paterson.

Other titbits? Over 34 years, the mean book size has remained around 333 pages but either I have gotten better at selecting books or they are just getting better as my mark out of ten for quality has increased steadily by 20%. I read about 18000 pages each to my first two sons and 23000 to my third (will that make a difference to him?). The most books that I have read from an author is Tanith Lee (53), most pages is David Eddings (12848 – a favourite of reading to my wife on long car trips, pre-kids) and the highest consistent quality goes to J.R.R. Tolkien and Guy Gavriel Kay (9.2/10). The book that I have read the most? The Hobbit (8 times).

Identifying trends in ecology is vitally important. Essentially, ecology is about understanding why species interact the way they do, what they did in the past and what we predict they might do in the future. Predicting the future is very important to research areas like pest control. We are constantly trying to work out the best way to reduce populations and spend a lot of effort in predicting what will give us the best outcome.

Here in New Zealand we are very focussed on mammalian pest control. Virtually all mammal species in this country are introduced and many (most?) have become pest species. These pests have huge impacts on our native biodiversity through predation and competition and also disrupt our agriculture through disease transmission and damage. We have spent decades working on ways to plot their demise.

Charlie Eason (Lincoln University professor and head of the Cawthron Institute) has been involved in developing methods for mammalian pest control for the last few decades. In a new review in the New Zealand Journal of Zoology he, and several colleagues, look at trends that have developed over the last three decades and what that tells us about the future.

New Zealand is unusual in a global sense in that we use a lot of toxins to control our mammal pests. As we have no native terrestrial mammals (other than two bat species) toxins that kill mammals in general can be applied broadly to an area. By-kill of mammals other than the main target species is not a bad thing as they are pests as well. Not surprisingly, our history of pest control is tied around developing toxins and the best practice to achieve high kill rates. We are one of the few countries in the world that still register new toxins as we strive to find new and more species specific versions.

The review also covers the work done on developing better and more humane traps. The major benefit of this paper is to use the historical data to uncover trends that can lead to better predictions about the future. Charlie and colleagues suggest several avenues that we should be going down to better control mammalian pests. The most important point is that if new Zealand is to be free of predators by 2050 we need to be even better than we have been in the past.

The target of the toxins and traps and trends. A camera trap image from Adrian Paterson.

First, there is a need to retain and improve toxins and traps in use. Existing traps and toxins have been studied a lot and we are very good at removing all predators from quite large islands. They still have a role to play.

Second, new toxins and traps need to be developed. There are a number of species-specific toxins coming online which can be used more tactically. A lot of work is also going into better ways to deliver the toxin to the target animal and into lures that will attract the animal to the toxin. New traps are being designed that are smart and can detect the type of mammal interacting with them and respond appropriately. Traps that talk are also being examined. Wireless technology allows signals to be sent when traps have been activated and are due for maintenance, for example.

Third, genetic options of control need to be explored. Natural genetic mutations in mitochondrial DNA can cause infertility in males. Because this DNA is always inherited from the mother, the mutation can spread through a population even though the population declines (as more and more males are unable to breed successfully). This is known as the trojan female approach and is something that has the potential to work, with our assistance, in mammal pests. More explicit genetic modifications offer similar potential.

Fourth, to coordinate the multitude of groups working on all of the different areas of mammalian pest control in New Zealand, there needs to be some sort of coordinating group with oversight. Such a group can provide direction and encourage uptake.

A knowledge of the past and its trends can illuminate the present and give clues to the future. This is as true of toxins as it is of books.

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