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Response to habitat fragmentation |
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Vicar 
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Joined: 02 Sep 2004 Location: United Kingdom Status: Offline Points: 1184 |
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 Posted: 21 Sep 2009 at 5:48pm |
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I suspect that scent trails my be important for Adder, with a certain degree of 'auto pilot' when following a trail.
I'm pretty sure that basking sites are sometimes chosen due to scent markers, as they seem able to pick a basking spot before vegetation growth, which remains in sunlight. Time of year will also be a factor to consider, as males in mate-search mode seem oblivious to pretty much anything, including available cover. |
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Steve Langham - Chairman
Surrey Amphibian & Reptile Group |
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Jonathan
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Joined: 08 Sep 2009 Location: United Kingdom Status: Offline Points: 71 |
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Posted: 21 Sep 2009 at 8:03pm |
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Quite true, I watched a male in May 1985 search all around a busy car park next to the heathland, on one occasion I had to step in to stop a car parking on him, my footfall or movement attracted him toward me at great speed. This location was also at least 200m away from the nearest colony, quite bizaare. Edited by Jonathan |
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"England Expects"
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herpetologic2
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Joined: 15 Jun 2004 Location: United Kingdom Status: Offline Points: 1511 |
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Posted: 22 Sep 2009 at 12:22pm |
Its the markings on the male adder which seems to provide protection from bird predators. I have often thought that a freshly sloughed male adder making its way across a short sward would be a sitting duck - but evidence collected from those plasticine models in Portugal, England, Wales and Sweden suggest otherwise Jon |
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Report your sightings to the Record Pool http://arguk.org/recording
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Vanderklam
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Joined: 20 Apr 2008 Location: United Kingdom Status: Offline Points: 54 |
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Posted: 22 Sep 2009 at 3:31pm |
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Interesting stuff chaps!! Jon do you know of a link to this evidence, or is it yet to be published? But anybody have any ideas of how best to measure degrees habitat fragmentation. I could (I guess) combine many variables i.e. amount of edge, area of interior habitat, distance between frags (using GIS) etc. Any other suggestions?? Grateful for the input as always Kev |
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Kevin Palmer
Lecturer in Animal Management/Course Manager |
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calumma
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Joined: 27 Jun 2003 Location: United Kingdom Status: Offline Points: 375 |
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Posted: 09 Oct 2009 at 9:02am |
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Kevin
A few observations. I very much welcome your proposed study. If you would like to chat through details please don't hesitate to contact me directly. I am often disheartened to hear land managers claim that what I consider to be excessive management work can be proven to be beneficial because of the (apparent) increase in adder observations the following spring. There appears to be a basic lack of understanding regarding detectability. Rarely are such draconian management regimes adequately monitored. It is important that you consider detectability when making comparisons between areas. Capture-recaptre controls for differences in detectability, but you may not be able to achieve the minimum sample sizes. Reliably estimating reptile populations is very problematic and the available methods require significant time investment. You may be better off analysing presence data alone. Methods are available to help control for detectability when analysing presence data. I think you need to carefully consider your habitat variables when assessing fragmentation. I think that Steve's recommendation to define the area within a grid is the way to go. A grid has the additional advantage that it would fit in with the presence based analysis. Size of grid will depend upon the resolution of your available data and the habitat variables that you decide to analyse. I envisage the development of a site specific fragmentation coefficient that could then be compared against presence data. Edited by calumma |
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Vanderklam
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Joined: 20 Apr 2008 Location: United Kingdom Status: Offline Points: 54 |
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Posted: 09 Oct 2009 at 11:42pm |
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Thanks for your comments Lee. At this point I would like to add that I have offered this project as a dissertation title to some degree students with the University of Chester, so hopefully they will be able to commit to longer field seasons than myself (dam work commitments!!). I agree that comparing presence data with site specific fragmentation co-efficient would be the way forward for the purpose of this study. My data thus far dates back 3-4 years depending on the sub-population, but hopefully my students will work on developing this over the coming years. I am fortunate in that landowners and habitat managers alike are keeping an open mind with regards to their methods of habitat management, and they are keen to take greater consideration of adders in the application of their methods. I would certainly be interested in discussing this further. Will you be attending the ARC-BHS Joint Scientific Meeting in December? Otherwise I could always email. Best Kev |
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Kevin Palmer
Lecturer in Animal Management/Course Manager |
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calumma
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Joined: 27 Jun 2003 Location: United Kingdom Status: Offline Points: 375 |
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Posted: 10 Oct 2009 at 8:34am |
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Hoping to attend the meeting, but November to January events are all up in
the air due to an impending trip to Madagascar. Will you be attending the NW Regional ARGUK Meeting in Leeds this month? I'm giving a presentation there so its likely I will get to that one 
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Vanderklam
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Posted: 10 Oct 2009 at 5:30pm |
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I have only recently moved up North, and have found little time to familiarise myself with such upcoming events, so probably not Im afraid. BUT just in case, do you have the dates and venue etcetc?? I should be at the ARC/BHS meeting though, so may well see you there! |
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Kevin Palmer
Lecturer in Animal Management/Course Manager |
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calumma
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Joined: 27 Jun 2003 Location: United Kingdom Status: Offline Points: 375 |
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Posted: 11 Oct 2009 at 10:08am |
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Actually it's the Northern Meeting (not NW):
24 October. 10.15 am-4.00 pm. Northern Regional Conference, The Lecture Theatre, Leeds Art Gallery, The Headrow, Leeds City Centre, LS1 3AA. Registration: ?17.50 including lunch (?12.50 concessionary) Full details including a booking form are available on the ARG UK website. Edited by calumma |
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Vicar wrote: