Monday, 1 April 2013

Final Blog :( But It's Going To Be Really HOT!


Ladle, R. J., Firmino, J. V. L., Malhado, A. C. M., and Rodriguez-Durand, A. 2012. Unexplored Diversity and Conservation Potential of Neotropical Hot Caves. Conservation Biology. Vol. 26(6): 978-982. 
Available at:
http://onlinelibrary.wiley.com/store/10.1111/j.1523-1739.2012.01936.x/asset/cobi1936.pdf?v=1&t=heubis7x&s=ba891fb49a29536c4389ebecff08c4fe6327b4c0

Rodriguez-Durand, A. and Soto-Centeno, J. A. 2003. Temperature selection by tropical bats roosting in caves. Journal of Thermal Biology. Vol. 28: 465-468

SAUNA FOR THE FAUNA

Here it is. Last blog of the year. I may or may not be kind of sad about this...Anyways, I want to talk about Neotropical hot caves. These caves can reach temperatures as high as 40 degrees Celsius (Ladle et al., 2012) and have humidities ranging from 85 to 100%. The caves house a diverse amount of invertebrates that feed on the abundance of bat guano, so bats live in these hot caves as well. This coexistence between bats and invertebrates creates a very stable microclimate within these caves. Hot caves are defined as having one opening, having poorly ventilated chambers, and are more than 1km in total length (Ladle et al., 2012). The elevated temperatures in these hot caves are due to the heat radiating from the bodies of the high densities of bats and from decomposing guano (Ladle et al., 2012).

http://www.kentos.org.uk/Trip%20Reports/BorneoandMalayPeninsularAugust2009.htm

The picture above is not of a hot cave perse, this is due to the lack of information about these caves. It is impossible to find a picture of a Neotropical hot cave. Maybe the lack of information is due to the fact that these caves are way too hot, and house an unbearable stench (bat guano - yuck!). Even the cave-dwelling arthropod fauna is poorly known (Ladle et al., 2012). The main reason why these caves need to be protected is because we know so little about them. They are able to accomodate a diverse spectrum of species that are capable of coexisting together to form a unique microclimate - if that's not worth protecting, I don't know what is! The fact that a stable microclimate can be made and sustained in a smelly, dark, and humid hole is incredible!

A study was done in 2003 by Rodriguez-Durand et al., on two types of hot cave dwelling bats, Pteronotus quadridens (Sooty mustached bat) and Erophylla sezekorni (Buffy flower bat). These bats are able to live together in the same cave because they have different temperature preferences. The Sooty mustached bat was found in the deepest parts of the cave in temperatures ranging from 28-35 degrees celsius, and the Buffy flower bat was found in temperatures ranging from 25 to 28 degrees celsius (Rodriguez-Durand et al., 2003). Because of these species-specific temperature preferences, both of these bats can live in the same cave without having to compete for places to sleep etc. These bat species appear to be adapted to the hot conditions of the cave. They have physiological adaptations such as low basal metabolic rates, and morphologies that conserve water (Ladle et al., 2012).

Hot cave ecosystems around the world are threatened by human activities such as mining for construction materials, extraction of guano for fertilizer and tourism (Ladle et al., 2012). These caves have a distinct geomorphology which can be irreversibly altered by human activity. If the hot caves have increased air flow and decreased temperatures, the specialized species that live in the caves will abandon them and the cave will not be able to function. Another big issue for the protection of these caves is the loss of foraging grounds for the bats due to deforestation (Ladle et al., 2012). If the bats leave (due to lack of food), the caves will not be able to house the stable microclimate of arthropods and bats.

Sooty Mustached Bat
http://www.jamaicancaves.org/st_clair_100120.htm


Buffy Flower Bat
http://www.caymanwildlife.org/bat-buffyFlower.html

Word Count: 550 (sorry! it was the last one though :P)