Okinawa's Dry Typhoons

Divergent ecological responses to typhoon disturbance revealed via landscape-scale acoustic monitoring

“…Multi-site acoustic sensor arrays such as ours thus provide opportunity to monitor both local and regional biodiversity change, in turn providing critical new insight for conservation management (Roe et al, 2021;Sethi et al, 2020a;Van Parijs et al, 2015). The observed post-typhoon increase in anthropophony on the other hand, likely reflects a change in sound propagation driven by vegetative structural damage and thinning of previously dense habitats, as is often documented following large storms (Abbas et al, 2020;Elliott & Nino, 1960). We did not measure habitat structure directly, and so the causes of increases to anthropophony following typhoons Trami and Kong-Rey cannot be demonstrated empirically.…”

“…Such spatial insurance effects have the potential to contribute to landscape-scale stability and spatial portfolio effects by affecting population and community asynchrony (Loreau et al, 2003;Wang et al, 2021), and our results suggest that land use development can degrade the natural insurance capacity of Okinawa's forests. This study draws on prior knowledge of Okinawan biodiversity (Inoue et al, 2019;Itô et al, 2000;McWhirter et al, 1996), the performance of passive acoustic methods in this system (Ross et al, 2018(Ross et al, , 2021a, and the characteristics of typhoons and land use intensification across Okinawa Island (Elliott & Nino, 1960;Takeuchi et al, 1981). Such baseline data provides a critical backdrop against which our results stand, allowing us to infer species and soundscape responses to the joint threats of climate change and land use intensification from acoustic recordings of typhoons (Altwegg et al, 2017).…”

“…Regardless, our detected post-typhoon declines in H. diphone vocalisations—either through behavioural changes, distributional shifts, or local mortality—were consistent across >80% of the field sites in which this species was detected. Habitat specialism may explain the observed species-specific differences in vocalisation changes following the typhoons; H. diphone relies on undergrowth and bushes for foraging (Haneda & Okabe, 1970) and typhoon disturbance has the potential to alter the structure of this habitat (Abbas et al, 2020; Elliott & Nino, 1960), in turn affecting the invertebrate communities on which H. diphone feeds (Azuma et al, 1997). In contrast, the forest specialist O. elegans was not detected less frequently after the typhoons, suggesting that its habitat and/or foraging were unaffected by the typhoons, or perhaps that cavity nesting reduced typhoon impact by reducing exposure to extreme weather (Inoue et al, 2019).…”

Idea paper: An envelope model of ecological disturbance

“…Intense typhoons are brief even on an ecological time scale, but they leave lasting effects that do not return to their original state for years (White et al, 2017). Many animals may perish during the typhoon itself, but more still will find the habitat of their home range no longer suitable, the forest canopy salted over and blown out (Elliott & Nino, 1960) or the coral reef damaged (Nanami & Nishihira, 2002; White et al, 2013). This motivated me to find a model of disturbance that included an intense event with a slow subsequent recovery—a “Pluck” dynamic.…”

Idea paper: An envelope model of ecological disturbance

“…Intense typhoons are brief even on an ecological time scale, but they leave lasting effects that do not return to their original state for years (White et al, 2017). Many animals may perish during the typhoon itself, but more still will find the habitat of their home range no longer suitable, the forest canopy salted over and blown out (Elliott & Nino, 1960) or the coral reef damaged (Nanami & Nishihira, 2002;White et al, 2013). This motivated me to find a model of disturbance that included an intense event with a slow subsequent recovery -a "Pluck" dynamic.…”