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Natural disturbance reduces disease risk in endangered rainforest frog populations.

Roznik EA, Sapsford SJ, Pike DA, Schwarzkopf L, Alford RA - Sci Rep (2015)

Bottom Line: Here we show that a reduction of rainforest canopy cover caused by a severe tropical cyclone decreased the risk of endangered rainforest frogs (Litoria rheocola) becoming infected by a fungal pathogen (Batrachochytrium dendrobatidis).This could increase host survival and reduce the probability of epidemic disease outbreaks.For amphibian populations under immediate threat from this pathogen, targeted manipulation of canopy cover could increase the availability of warmer, drier microclimates and therefore tip the balance from host extinction to coexistence.

View Article: PubMed Central - PubMed

Affiliation: College of Marine and Environmental Sciences, James Cook University, Townsville, Queensland 4811, Australia.

ABSTRACT
Natural disturbances can drive disease dynamics in animal populations by altering the microclimates experienced by hosts and their pathogens. Many pathogens are highly sensitive to temperature and moisture, and therefore small changes in habitat structure can alter the microclimate in ways that increase or decrease infection prevalence and intensity in host populations. Here we show that a reduction of rainforest canopy cover caused by a severe tropical cyclone decreased the risk of endangered rainforest frogs (Litoria rheocola) becoming infected by a fungal pathogen (Batrachochytrium dendrobatidis). Reductions in canopy cover increased the temperatures and rates of evaporative water loss in frog microhabitats, which reduced B. dendrobatidis infection risk in frogs by an average of 11-28% in cyclone-damaged areas, relative to unaffected areas. Natural disturbances to the rainforest canopy can therefore provide an immediate benefit to frogs by altering the microclimate in ways that reduce infection risk. This could increase host survival and reduce the probability of epidemic disease outbreaks. For amphibian populations under immediate threat from this pathogen, targeted manipulation of canopy cover could increase the availability of warmer, drier microclimates and therefore tip the balance from host extinction to coexistence.

No MeSH data available.


Related in: MedlinePlus

Severe Tropical Cyclone Yasi impacted the northeastern coast of Queensland, Australia, on 2–3 February 2011.Shown are (a) a satellite image of the cyclone approaching the coast (a star denotes our study region, and the inset shows this location within Australia), hemispherical photographs of the rainforest canopy above Stoney Creek taken from the same location at 80 m along our stream transect both (b) before and (c) after the cyclone and showing the canopy cover at that site (88% and 60%, respectively), and ground-level images of Stoney Creek (taken from different locations) both (d) before and (e) after the cyclone. Images were provided by (a) NASA (by the MODIS instrument on NASA’s Aqua satellite, taken at 13:35 Australian Eastern Standard Time on 2 February 2011. This image is not copyrighted and is used under NASA’s open access policy; the image is available at http://www.nasa.gov/images/content/514455main_Yasi-MODIS-WEDNESDAY-LARGE.jpg. We imported the image into ArcGIS 9.3 to create a map), (b,c) Sarah Sapsford, (d) Angus McNab, and (e) Elizabeth Roznik.
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f1: Severe Tropical Cyclone Yasi impacted the northeastern coast of Queensland, Australia, on 2–3 February 2011.Shown are (a) a satellite image of the cyclone approaching the coast (a star denotes our study region, and the inset shows this location within Australia), hemispherical photographs of the rainforest canopy above Stoney Creek taken from the same location at 80 m along our stream transect both (b) before and (c) after the cyclone and showing the canopy cover at that site (88% and 60%, respectively), and ground-level images of Stoney Creek (taken from different locations) both (d) before and (e) after the cyclone. Images were provided by (a) NASA (by the MODIS instrument on NASA’s Aqua satellite, taken at 13:35 Australian Eastern Standard Time on 2 February 2011. This image is not copyrighted and is used under NASA’s open access policy; the image is available at http://www.nasa.gov/images/content/514455main_Yasi-MODIS-WEDNESDAY-LARGE.jpg. We imported the image into ArcGIS 9.3 to create a map), (b,c) Sarah Sapsford, (d) Angus McNab, and (e) Elizabeth Roznik.

Mentions: Structural damage can alter the microclimates available to animals living beneath the canopy3839, and such changes could be important drivers of B. dendrobatidis infection dynamics because many forested areas are subject to natural disturbances that reduce canopy cover. Strong winds, such as those accompanying cyclones and hurricanes, can cause great damage to the canopy structure in tropical rainforests3839. Understanding how these forces influence habitat structure, microclimatic conditions, and host-pathogen interactions is extremely difficult due to their stochastic nature in space and time. Our landscape-scale study of seasonal B. dendrobatidis infection dynamics in the endangered rainforest frog Litoria rheocola was unexpectedly impacted by Severe Tropical Cyclone Yasi in February 2011 (Fig. 1). Although all of the six study sites were in the path of the cyclone, some sites experienced no change in canopy cover, whereas in other sites, the canopy was substantially reduced. We predicted that these changes in canopy structure and microclimate caused by the cyclone would benefit frogs by reducing infection risk, and that these effects would be an immediate and positive outcome of storm systems that otherwise cause widespread destruction.


Natural disturbance reduces disease risk in endangered rainforest frog populations.

Roznik EA, Sapsford SJ, Pike DA, Schwarzkopf L, Alford RA - Sci Rep (2015)

Severe Tropical Cyclone Yasi impacted the northeastern coast of Queensland, Australia, on 2–3 February 2011.Shown are (a) a satellite image of the cyclone approaching the coast (a star denotes our study region, and the inset shows this location within Australia), hemispherical photographs of the rainforest canopy above Stoney Creek taken from the same location at 80 m along our stream transect both (b) before and (c) after the cyclone and showing the canopy cover at that site (88% and 60%, respectively), and ground-level images of Stoney Creek (taken from different locations) both (d) before and (e) after the cyclone. Images were provided by (a) NASA (by the MODIS instrument on NASA’s Aqua satellite, taken at 13:35 Australian Eastern Standard Time on 2 February 2011. This image is not copyrighted and is used under NASA’s open access policy; the image is available at http://www.nasa.gov/images/content/514455main_Yasi-MODIS-WEDNESDAY-LARGE.jpg. We imported the image into ArcGIS 9.3 to create a map), (b,c) Sarah Sapsford, (d) Angus McNab, and (e) Elizabeth Roznik.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4544035&req=5

f1: Severe Tropical Cyclone Yasi impacted the northeastern coast of Queensland, Australia, on 2–3 February 2011.Shown are (a) a satellite image of the cyclone approaching the coast (a star denotes our study region, and the inset shows this location within Australia), hemispherical photographs of the rainforest canopy above Stoney Creek taken from the same location at 80 m along our stream transect both (b) before and (c) after the cyclone and showing the canopy cover at that site (88% and 60%, respectively), and ground-level images of Stoney Creek (taken from different locations) both (d) before and (e) after the cyclone. Images were provided by (a) NASA (by the MODIS instrument on NASA’s Aqua satellite, taken at 13:35 Australian Eastern Standard Time on 2 February 2011. This image is not copyrighted and is used under NASA’s open access policy; the image is available at http://www.nasa.gov/images/content/514455main_Yasi-MODIS-WEDNESDAY-LARGE.jpg. We imported the image into ArcGIS 9.3 to create a map), (b,c) Sarah Sapsford, (d) Angus McNab, and (e) Elizabeth Roznik.
Mentions: Structural damage can alter the microclimates available to animals living beneath the canopy3839, and such changes could be important drivers of B. dendrobatidis infection dynamics because many forested areas are subject to natural disturbances that reduce canopy cover. Strong winds, such as those accompanying cyclones and hurricanes, can cause great damage to the canopy structure in tropical rainforests3839. Understanding how these forces influence habitat structure, microclimatic conditions, and host-pathogen interactions is extremely difficult due to their stochastic nature in space and time. Our landscape-scale study of seasonal B. dendrobatidis infection dynamics in the endangered rainforest frog Litoria rheocola was unexpectedly impacted by Severe Tropical Cyclone Yasi in February 2011 (Fig. 1). Although all of the six study sites were in the path of the cyclone, some sites experienced no change in canopy cover, whereas in other sites, the canopy was substantially reduced. We predicted that these changes in canopy structure and microclimate caused by the cyclone would benefit frogs by reducing infection risk, and that these effects would be an immediate and positive outcome of storm systems that otherwise cause widespread destruction.

Bottom Line: Here we show that a reduction of rainforest canopy cover caused by a severe tropical cyclone decreased the risk of endangered rainforest frogs (Litoria rheocola) becoming infected by a fungal pathogen (Batrachochytrium dendrobatidis).This could increase host survival and reduce the probability of epidemic disease outbreaks.For amphibian populations under immediate threat from this pathogen, targeted manipulation of canopy cover could increase the availability of warmer, drier microclimates and therefore tip the balance from host extinction to coexistence.

View Article: PubMed Central - PubMed

Affiliation: College of Marine and Environmental Sciences, James Cook University, Townsville, Queensland 4811, Australia.

ABSTRACT
Natural disturbances can drive disease dynamics in animal populations by altering the microclimates experienced by hosts and their pathogens. Many pathogens are highly sensitive to temperature and moisture, and therefore small changes in habitat structure can alter the microclimate in ways that increase or decrease infection prevalence and intensity in host populations. Here we show that a reduction of rainforest canopy cover caused by a severe tropical cyclone decreased the risk of endangered rainforest frogs (Litoria rheocola) becoming infected by a fungal pathogen (Batrachochytrium dendrobatidis). Reductions in canopy cover increased the temperatures and rates of evaporative water loss in frog microhabitats, which reduced B. dendrobatidis infection risk in frogs by an average of 11-28% in cyclone-damaged areas, relative to unaffected areas. Natural disturbances to the rainforest canopy can therefore provide an immediate benefit to frogs by altering the microclimate in ways that reduce infection risk. This could increase host survival and reduce the probability of epidemic disease outbreaks. For amphibian populations under immediate threat from this pathogen, targeted manipulation of canopy cover could increase the availability of warmer, drier microclimates and therefore tip the balance from host extinction to coexistence.

No MeSH data available.


Related in: MedlinePlus