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Meyer, E. R. , What do search experiments show about how to assess box turtle habitats and populations? Paper presented at Third Box Turtle Conservation Workshop.
Added by: Admin (14 Aug 2008 20:33:45 UTC) |
| Resource type: Proceedings Article BibTeX citation key: Meyer2007 View all bibliographic details  |
Categories: General Keywords: Habitat = habitat, Nordamerika = North America, Schildkröten = turtles + tortoises Creators: Meyer Collection: Third Box Turtle Conservation Workshop |
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| Abstract |
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Search experiments can show how detectable animals are. An example is an experiment finding box turtle shells at Jug Bay. We asked volunteers to find shells at randomized locations. The shells were either entirely above the leaf litter or half-buried by leaves. Findings: 93% of the completely exposed shells were found by each search; they were in areas easy to walk thru. The find rates drop to about half, for shells half covered by leaves. The find rate dropped to zero for a shell that was placed randomly in a brushy area searchable easily only if a person walked on a narrow trail thru dense bushes. It was never found even when five people, some with years of field experience, looked for it. Most of my search experiments use a variety of lifelike plastic replicas of snakes and amphibians in addition to turtles. The advantages of using several species include comparing taxa that intuitively seem camouflaged in different ways, and piggybacking work on species with populations that are not well documented, with species known to be restricted or imperiled. Setting up search experiments is a learning experience as much as the results. Deciding the kinds of places to put shells or replicas leads to seeing the choices that a species makes in choosing habitat and cover. Detectability is the subject of much recent work on salamander populations, and a good article for an aquatic turtle population, and summarizing those articles shows that choosing habitats requires knowing the breadth and time of habitat use. Fortunately, knowledge of box turtle movements and habitat uses is now much clearer from Jug Bay’s recent telemetry and census surveys. Training: search experiments gave me and other searchers (1) visual training for what the species look like partially concealed on actual backgrounds, and (2) walking training, meaning useful ways to walk thru a particular cover. This clarified how we look around, and how we walk around, visual screens. I will show how to set up a brief search experiment. First key detail: briefing searchers before an experiment is useful. We always start by picking up a sample so that we know what it looks like in a habitat. My instructions always state that we will find how an animal’s camouflage works in this habitat. It is definitely not an evaluation of individual searchers. It is a test of that species camouflage and location choices. Second key detail: at the end of a search I offer a debrief to show any that were missed. This can be a much-appreciated learning opportunity for each searcher. This presentation is intended to aid the participants’ conservation interests. The solutions to problems of detectability can be as simple as measuring them in ways that teach us while setting up an experiment that volunteers will enjoy searching, and that show afresh how we walk and look for species that can be remarkably camouflaged.
Added by: Admin |