the online meeting place for all who love our amphibians and reptiles |
|
Adder Dispersal Distances |
Post Reply | Page <1 678 |
Author | |
AGILIS
Senior Member Joined: 27 Feb 2007 Location: United Kingdom Status: Offline Points: 1689 |
Post Options
Thanks(0)
|
Thing is, you can do what you like if you have royal patronage in front of your sociaty name what about a royal sociaty for the protection of hissing snakes(herping) or should say RSPH Royal sociaty for the protection of herpetology ,perhaps we should apply for a royal patronage cant see the Queen or Chiller signing up to that can you So let the heathland burning begin or usual bulldozings like Hyde heath Stoborough, keith
Edited by AGILIS |
|
LOCAL ICYNICAL CELTIC ECO WARRIOR AND FAILED DRUID
|
|
Vicar
Senior Member Joined: 02 Sep 2004 Location: United Kingdom Status: Offline Points: 1184 |
Post Options
Thanks(0)
|
I've been looking at ways to improve the adder HSI for Surrey.
The current method looks for grids which exactly match known locations...which is very sensitive to changes in known distribution. I've now looked at the mean habitat profile for adder, which is basically working out what a grid square would look like to be suitable for adder occupancy. Adding statistically derived confidence limits over this mean profile provides a filter which can be checked against all grids in the county. When you apply this filter, you get a similar number of matches to the exact method, but the habitat appears to be better represented, in blocks of grids with similar habitat type. To test both methods, I've overlain the ARC(HCT) 'Add an adder' records for Surrey. This is low-confidence data, but is independent and does seem to provide a good test from face validation. As always: Black squares = known distribution Orange = predicted range Yellow = modelled suitable habitat The red dots are the 'add an adder' records. Getting there ! Steve Edited by Vicar |
|
Suzi
Senior Member Joined: 06 Apr 2005 Location: United Kingdom Status: Offline Points: 1025 |
Post Options
Thanks(0)
|
I know of a very small heath which was isolated from the main heathland area (large) during WW2 in the push to get more land under cultivation when fields were created between this heathland area and the now main block . These newly created fields have been kept thus and the once small lane between this small heath and the fields is now a busyish road. There is an adder population (slow worms and lizards also seen). There are likely grass snake as there is a good proportion of damp bottom land that has long heathy type grass. With the road (sunken down from the heath) and very large fields needing crossing before the main heath is reached there is little chance of reptile movement to and fro. This small heath is totally unmanaged and interesting for that. Lots of heather, small copses, some gorse and grassy areas. It also seems there are more heathland birds and butterflies than on the managed areas but that is hard to prove.
|
|
Suz
|
|
Vicar
Senior Member Joined: 02 Sep 2004 Location: United Kingdom Status: Offline Points: 1184 |
Post Options
Thanks(0)
|
A lot more work has gone into the conservation status modeling, the results of which are now available online:
http://surrey-arg.org.uk/SARG/08000-TheAnimals/ConservationS tatus.asp There are now Vice County population estimates for some species: The nearest neighbour analysis is available for each species, which shows how likely the animals are to occur from the closest known location. This is less to do with how far the animals travel than it is to do with how sparse the known data set is compared with ground truth. These graphs show that if you receive a request for an ecological data search, supporting a desk study, where the consultants request (say) a 1km radius, then there is a significant probability that animal presence will be underplayed. In most cases, a 2km radius will provide close to 90% confidence (although it varies by species). I'm working on making the model accessible to other ARGs/Orgs via the website, so people can add their own data and see results for their own Vice County. Edited by Vicar |
|
sussexecology
Senior Member Joined: 30 Sep 2010 Location: United Kingdom Status: Offline Points: 411 |
Post Options
Thanks(0)
|
Hi Lee Good to see you around here. Good question regarding the adders and thank you for posting this thread on here. I would go with the advice of using data from early in the year to determine hibernation sites and then look at potential habitat where they could disperse. To be honest,I don't think you are really going to know unless you do very intensive survey work (ie photographing each one seen in the early part of the year, compared to those seen in the summer. Good luck and let me know how you get on. I'll be doing some adder surveys this year and will forward you any data that is collected, particularly on hibernation sites and animals found in the summer. It is an interesting topic and one that I have always been fascinated by- but these adders don't always read the books!! |
|
AGILIS
Senior Member Joined: 27 Feb 2007 Location: United Kingdom Status: Offline Points: 1689 |
Post Options
Thanks(0)
|
After reading your note Tony you say fear to go to Dorset
sites ,Is that because you dread to see what destruction that may have have occurred during your away time?? every time I go to the Wareham area It always seems that the idiots have been ripping into the habitat with bulldozers on the Hyde heaths areas of Furze brook road.keith 22_072513_2010_0814dorset0009.JPG"> Edited by AGILIS |
|
LOCAL ICYNICAL CELTIC ECO WARRIOR AND FAILED DRUID
|
|
administrator
Admin Group Joined: 01 Jan 2007 Status: Offline Points: 10 |
Post Options
Thanks(0)
|
Keith we ought to form a 'displaced' herpers society for all of us who simply can't visit some of our best sites from the past for fear of what has happened since we were last there. It's crap being at the sharp end sometimes. I think Tony though will have to be the founding member, little compares to the destruction of his study sites from which he collected data for many years which prompted a move to SA. I must admit leaving the UK and it's pitiful attempts at 'conservation' occurs to me quite often too.
|
|
AGILIS
Senior Member Joined: 27 Feb 2007 Location: United Kingdom Status: Offline Points: 1689 |
Post Options
Thanks(0)
|
Gemma I know exactly how you feel,every time I
venture out I am wondering what tidy up brigade or development has been unleashed on the habitat! I cant wait to get back to West Aus but even there habitat and flora & fauna are under pressure with todays population growth and ignorance. |
|
LOCAL ICYNICAL CELTIC ECO WARRIOR AND FAILED DRUID
|
|
Mark_b
Senior Member Joined: 26 Jun 2008 Location: United Kingdom Status: Offline Points: 155 |
Post Options
Thanks(0)
|
I was just wondering if anything had happened with this and how well it would work in counties (i.e. Swansea/Neath Port talbot) that are tremendously under recorded. |
|
calumma
Senior Member Joined: 27 Jun 2003 Location: United Kingdom Status: Offline Points: 375 |
Post Options
Thanks(0)
|
Things tend to get more accurate the more data is available. That said, predictive models based on nearest neighbour and landscape level habitat from one county could be used to predict where a species may occur in another county. I suspect that the relability of such an exercise would depend on how similar the two areas were, but still it would be interesting to try. I'm trying to do something like this as part of KRAG's INTERREG project in northern France, using the Kent data as a baseline.
|
|
Post Reply | Page <1 678 |
Tweet
|
Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |