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  1. #101
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    Quote Originally Posted by Elizabeth Freer View Post
    Welcome aboard!

    I wonder how Mark's trip went too.
    Thanks for the warm welcome!
    6.7.8 ( and counting) R.Ciliatus
    0.1.1 E. Macularius
    1.1 U.Henkeli
    1.1 U. Fimbriatus
    1.1 U.Giganteus
    0.0.1 P. Standingi
    1.1.2 T.Keyserlingi
    1.1 T. Scincus
    1.1 T. Roborowskii
    1.1 R. Auriculatus
    Hoping for P.Rangei soon , very soon
    Likes Elizabeth Freer liked this post

  2. #102
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    Well, I'll keep it brief for now. We found quite a few Uroplatus (14 U. aff. ebenaui sp. Ca1 and three U. sikorae), but all of them, without exception, at night. I took UV measurements in a few of the locations during the day to try to get an indication of what they might be experiencing, but it read zero for UVA and UVB in pretty much every case. I suspect that this is incorrect though, because the device went a little haywire in the humidity.
    The good news is, I am going back to Madagascar for November and half of October, and will try to get more data from some other forests and species again. Assuming that I get permission from Markus, who loaned me his Solarmeter for the trip (which I have yet to return to him), I will again make an effort to take UV measurements every time we encounter Uroplatus, but this time from Marojejy and the Andasibe area (north and east).
    In the long run though, I think that it will be necessary to get a more accurate or less humidity-sensitive device for measurement, because currently I am sceptical as to the reliability of the Solarmeter. In any case, such an accurate device will be important for me to acquire over the course of the next year, as I will be spending three months on Montagne d'Ambre at the end of 2017, and will certainly try to get some decent UV readings there.
    So, I should have more data on this topic after mid-December, and I will try not to leave it so long before my next report!

    Cheers,
    Mark
    Mark D. Scherz, MSc
    Herpetologist and Evolutionary Biologist
    PhD Candidate: Evolution and Systematics of Madagascar's Herpetofauna
    Ludwig-Maximilian University, Munich
    Zoologische Staatssammlung Mnchen
    www.markscherz.com
    Twitter, Tumblr
    Thanks miguel camacho!, Tamara, Elizabeth Freer thanked for this post

  3. #103
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    How did the UV readings go last year?
    1.1 fimbriatus adults ,
    1.1 juvie fimbriatus,
    1.1 phantasticus
    0.2 leopard geckos
    And then there's the non-gecko babies...

  4. #104
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    Feb 2006
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    Lightbulb

    Here is a report on what I have found so far from the last three expeditions with a Solarmeter 6.2 to the rainforests of Madagascar:

    I have tried to make measurements in Montagne dAmbre this year, Marojejy in 2016, and in a high-altitude forest near Bealanana in northern Madagascar in 2015-16. My observations are therefore directly relevant to Uroplatus sikorae, U. sameiti, U. giganteus, U. aff. henkeli Ca11, U. ebenaui, U. finiavana, U. fotsivava, U. lineatus, and U. alluaudi (and a few undescribed species that are not yet public knowledge), but I think they can be generalised over all Uroplatus species with the correct level of caution. See below.

    First of all, I want you to be aware that there have been MAJOR challenges in assessing the UV exposure of Uroplatus:
    (1) We have had a lot of trouble with the Solarmeter readings because they vary dramatically within centimetre distances. How do you standardise the measurements? Over the last three expeditions, I have not had any success at all finding a way to take these measurements in a standardized way, in part because I find it difficult to integrate the Solarmeter usage into my daily regime, and in consequence do not use it as often as could be desired, and never in a standardized way. I tried this year to have a student collect the data over transects whilst looking for chameleons, but in the end it was too tedious, unreliable, and time-consuming to be continued. Not to mention rainy!
    (2) Over the last three expeditions, cumulatively half a year IN the forest, I have found a grand total of maybe three Uroplatus during the day, and in none of those instances did I have the solarmeter with me (doh!). Measurements taken in the proximity of geckos found during the day are out of the question in terms of usefulness, because they simply are not numerous enough to be statistically useful.
    (3) There are dramatic differences to be accounted for depending on the perching habits of the species, making generalisations difficult. Bark-mimic species (henkeli complex, giganteus, fimbriatus, sikorae/sameiti complex, but also to a lesser extent alluaudi, guentheri, peitschmanni, and malahelo) may at times be exposed to full sun for brief moments, but probably not for long. The angle at which light hits them is always steep, and typically they are experiencing diffuse light because they are on the trunks of trees, where there is the most shade. By contrast, leaf-mimic species tend to be mostly or completely sheltered during the day, exposing only part of their bodies at all to the light, and certainly not basking. So what is the relevance of environmental UVB readings at all to these animals, which are generally hidden from the light?
    (4) Light in the forest varies dramatically (1) by time of day, (2) by position, (3) by canopy type, (3) by microhabitat, (4) by altitude, and most strongly (5) by season. We have worked the last three years in the rainy season, where light is lowest and rainfall is heaviest, and where in a single day we have massive swings from dark-as-night cloud cover to bright direct sunlight to diffuse light with or without rain. Needless to say, readings at a single moment in the day are not helpful, because we need an impression of the average exposure of the species to advise husbandry.

    Given all of these caveats, you will I hope understand why what I have to report is fragmentary and perhaps not obviously useful. But I have learned a lot about the habitats where Uroplatus are occurring, and what I have learned I hope I can share in a constructive manner. Before I report, let me just say that I am very happy to talk to people both one-on-one and in form of public discussion about the ecology of all Uroplatus species, so if you have direct questions about husbandry and ecology, please do not hesitate to ask! I may not be a big Uroplatus keeper, but I have learned a thing or two about these geckos over the last few years.

    So about the observations I have made so far: UVB levels within the forest typically range from 0 to 15 W/cm2. In dense primary forest, usually we are getting 0-2 W/cm2, with upwards of 5 in more open areas, and sometimes up to 15 W/cm2 in patches where the sun is shining at that very moment. In more open forests, the maximum Ive seen is up to 30 W/cm2, but sometimes we can get as much as 50 W/cm2 in really blazing sun (probably more frequent in the dry season!). Outside the forest and on its edge we are getting triple digits sometimes, but this is really in areas where Uroplatus basically never occur (maybe useful if anyone keeps edge-loving chameleons though, especially Furcifer pardalis, F. petteri, and Calumma nasutum group species).

    All in all, I would guess that the maximum a rainforest Uroplatus is ever exposed to is probably 30 W/cm2, and as I have said above, this is probably more than a leaf-mimic species ever experiences. I would not consider this value average however. I would guess that because the geckos really do not seem to bask, and rather are hit coincidentally by light as the sun moves across the sky, the average exposure of any Uroplatus is probably between 8 and 10 W/cm2, and lower in leaf-mimics. Thinking about the drier forest Uroplatus, where the canopy is less dense, I would raise these numbers a bit and say 10-15 W/cm2 is a likely good average (again lower in leaf-mimics from drier forest, so U. malama and U. ebenaui).

    Bear in mind that altitude also plays a big role: lower altitudes have less cloud cover, and typically more bright-sun-days per year than higher altitudes. So for example, U. ebenaui and U. finiavana may both occur in Montagne dAmbre, but the latter occurs at higher altitudes than the former, and in more dense forest, and as a result, it must receive considerably less UV exposure. Fortunately, altitude and forest-type correlate rather strongly, so as long as you adjust UV levels for one or the other, you should come out okay.
    Uroplatus pietschmanni (and possibly U. alluaudi) is probably exceptional, because it is a high-canopy species and as such probably has higher UV exposure than its relatives. I would guess that increasing by one or two W/cm2 would cover this difference though. Uroplatus lineatus is also exceptional because bamboo forest has higher light levels than deciduous or rainforest. As such, I would keep U. lineatus with higher light levels in general, and slightly higher UV levels than e.g. U. giganteus, which occurs in the rainforests beside the bamboo forest of U. lineatus.

    Bear in mind when thinking about your husbandry that the weather is constantly changing in the forest. Clouds make UVB exposure swing massively. Replicates of natural environments in little boxes cannot mimic this effect, so it is safer to go with a lower-side-of-average value, rather than go straight for the high values of UV exposure. On the other hand, I think it would not be unreasonable to treat leaf- and bark-mimic Uroplatus from the same location with the same exposure, and simply provide more shelter opportunities for leaf-mimics... This would be more representative of their natural conditions. But I will leave this to you to decide.

    Please take everything I am saying with a healthy dose of salt as I say I have not had a single opportunity to take measurements on geckos at rest over the last six months of fieldwork. But I hope that these impressions give some insight into these animals. And as I have already said, if you have any questions, please do not hesitate to ask. Talking about Uroplatus is one of my favourite things to do.

    I have more to say on this issue, but for now do not have the concentration or time, so I will leave you with that. I hope it is helpful.

    Cheers from rainy Antananarivo,
    Mark
    Mark D. Scherz, MSc
    Herpetologist and Evolutionary Biologist
    PhD Candidate: Evolution and Systematics of Madagascar's Herpetofauna
    Ludwig-Maximilian University, Munich
    Zoologische Staatssammlung Mnchen
    www.markscherz.com
    Twitter, Tumblr

  5. #105
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    Thank you, Mark.
    This is an extremely helpful and valuable set of observations.
    Frances Baines
    UV Guide UK
    Thanks Thecoldandfuzzies, Elizabeth Freer, the moof thanked for this post
    Likes Thecoldandfuzzies liked this post

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