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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

Boxplots of canopy cover (%) before and after Cyclone Yasi at two sites that were damaged significantly by the cyclone, and at four sites that were not damaged significantly (see Table 1 for statistical results).
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f2: Boxplots of canopy cover (%) before and after Cyclone Yasi at two sites that were damaged significantly by the cyclone, and at four sites that were not damaged significantly (see Table 1 for statistical results).

Mentions: We quantified the thermal and hydric conditions available to frogs under different levels of canopy cover by placing models on top of rocks in the streambed that are similar to rocks used by L. rheocola18. We placed 100 models on rocks along a 400-m section of stream at Frenchman Creek (a site with substantial variation in canopy cover; Fig. 2) for 24 hr in October 2011. We took a hemispherical photograph above each model, and determined canopy cover (%) using Gap Light Analyzer software47. Dataloggers recorded temperatures at 15-min intervals, which we used to calculate the mean temperature during the warmest part of the day (10:00–16:00) for each model. We also measured desiccation rates for model locations, expressed as the percentage of model mass lost due to water loss over 24 hr, by weighing each model (to 0.1 g) before and after field placement4851. We used linear regressions to test for relationships between canopy cover and mean daytime temperature, and canopy cover and desiccation rate.


Natural disturbance reduces disease risk in endangered rainforest frog populations.

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

Boxplots of canopy cover (%) before and after Cyclone Yasi at two sites that were damaged significantly by the cyclone, and at four sites that were not damaged significantly (see Table 1 for statistical results).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f2: Boxplots of canopy cover (%) before and after Cyclone Yasi at two sites that were damaged significantly by the cyclone, and at four sites that were not damaged significantly (see Table 1 for statistical results).
Mentions: We quantified the thermal and hydric conditions available to frogs under different levels of canopy cover by placing models on top of rocks in the streambed that are similar to rocks used by L. rheocola18. We placed 100 models on rocks along a 400-m section of stream at Frenchman Creek (a site with substantial variation in canopy cover; Fig. 2) for 24 hr in October 2011. We took a hemispherical photograph above each model, and determined canopy cover (%) using Gap Light Analyzer software47. Dataloggers recorded temperatures at 15-min intervals, which we used to calculate the mean temperature during the warmest part of the day (10:00–16:00) for each model. We also measured desiccation rates for model locations, expressed as the percentage of model mass lost due to water loss over 24 hr, by weighing each model (to 0.1 g) before and after field placement4851. We used linear regressions to test for relationships between canopy cover and mean daytime temperature, and canopy cover and desiccation rate.

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