Like most ecologists the start of the survey season means one thing for the Landmark Practice’s Itinerant Ecologist…
(or GCN for those who love an acronym!)
The Itinerant Ecologist had a busy 2014 surveying ponds, undertaking surveys at a number of sites across the Mild Mild West. As some of you may already know GCN surveys require each pond to be surveyed with a range of different survey techniques on either four (for presence/absence) or six (for population class size) separate visits, depending on whether you are just trying to find out if they’re there or whether you need to know how many (ish) are there.
Usually by mid-June (the recognised end of the GCN survey season), most surveyors have had their fill of waders, late finishes, early starts and car boots full of wet bottle traps. Not the Itinerant Ecologist, who jumped (literally) at the chance to do some extra-curricular pond surveys using the novel method of surveying using box (or Dewsbury, as they’re also known) traps. It should be noted that as a novel survey technique this method is not covered by either Class 1 or Class 2 Survey Licenses (in-fact there is a specific caveat excluding this method for all those sharp-eyed small print aficionados) and a personal license is required. Conveniently the Itinerant Ecologist knows just such a gentleman with such wisdom.
Box traps function in a similar way to the bottle traps which most ecologists are overly familiar with. Bottle traps have to be set at the surface where there are less newts passing by, this coupled with the relatively narrow opening of the bottle can, in some cases (waterbody dependent), reduce the likelihood of capture. Additionally there are a range of welfare issues relating to the use of bottle traps as newts (as an air breathing animal) are at some risk to suffocation. Some (limited) comparisons have been undertaken on the efficacy of bottle vs box traps, though to the Itinerant Ecologist’s knowledge (which, while extensive is hardly exhaustive) no comprehensive study has been published (though a number of people are undertaking research).
Box traps, are small weighted plastic boxes with a small entrance fringed with plastic mesh to allow ingress but not egress. A plastic bag is secured to the open top of the box and a float with vent is placed in the top of the box. This float and vent provides a continuous supply of air.
The box is easily deployed and retrieved from the bank limiting the need to enter the pond, a positive from a health and safety standpoint, limiting disturbance to the pond. Upon deployment the weighted box sinks and the plastic bag inflates. This locates the trap at greater depth, increasing the likelihood of newt capture and the continuous supply of air decreases the potential hazards to captured newts.
During the surveys that the Itinerant Ecologist took part in both box traps and bottle traps were used and the ponds surveyed had known populations of GCN.
So, the questions on everyone’s lips, “Did you catch any newts?” and “How did they compare?”
From our limited survey sample, the box traps were hands-down more effective. All of the box traps caught newts with one trap almost overflowing due to the numbers caught. It should be noted that these initial experiments were not comprehensive, and there are any number of variables which could have biased the results in favour of the box traps.
Suffice it to say while further research is needed, from the Itinerant Ecologist’s limited experience, box traps show some promise.
The Itinerant Ecologist and compatriots plan to undertake further comparative surveys in spring 2015. We’ll keep you updated!