Oct

30

2007
 
 

Muck spreadsheet



Scientists devise a way to get more from their field sign samples

it's a tough life... if you're a biologistVisitation rates are crucial to understanding complex conservation issues, such as predator attacks on livestock. Such information can be all but impossible to directly observe, so researchers often resort to grubbier methods: rather than filming filming bears attacking sheep they instead find themselves rummaging around in the undergrowth for evidence – you know, the usual kind – of activity. Bernd Gruber, an ecologist at the Helmholtz Centre for Environmental Research, Leipzig, and colleagues have devised a more accurate way of using this, er, evidence. Traditional methods rely on simple counts of scats or other sign near to the area of interest, but Gruber’s team present a maximum likelihood statistical approach to glean additional detail. They field-tested their new technique by collecting fresh and not-so-fresh otter Lutra lutra spraints near a pond in Germany, where the pesky mustelids had been wreaking havoc on the fish population. Their findings, published in the Journal of Applied Ecology, gave a more accurate picture of how many visits otters were making. If you feel like giving the new method a go, download the computer spreadsheet from Gruber’s webpage, pull on your rubber gloves, and head for the countryside. Source: Gruber B, Reineking B, Calabrese JM, Kranz A, Poledníková K, Poledník L, Klenke R, Valentin A & Henle K (2007) A new method for estimating visitation rates of cryptic animals via repeated surveys of indirect signs. Journal of Applied Ecology DOI: 10.1111/j.1365-2664.2007.01406.x

Image © Darren Hunt

Filed Under Habitat, Fresh water, Monitoring, Tools and technology | 

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