Biology subjects

Dudley, K. L.

Publications and source records attributed to Dudley, K. L..

3 recordsLinked to original sources

bioRxiv2024

Urbanization of a subtropical island (Okinawa, Japan) alters physicochemical characteristics and disrupts microbial community dynamics in nearshore ecosystems

Subtropical and tropical islands are undergoing rapid urbanization as human populations and tourism expand worldwide. Urbanization disrupts coastal ecosystems by replacing forests and other natural habitats with roads, parking lots, and buildings. These impervious surfaces increase the amount of runoff and pollution that reaches coastal ecosystems. Urbanization also comes with increased industry, waste treatment needs, fishing and aquaculture pressure, and coastline engineering. Despite the major changes to coasts that accompany urbanization, specific impacts on marine ecosystems can be difficult to measure due to missing baselines. Here, we take advantage of a large gradient in urbanization on the subtropical island of Okinawa, Japan, to evaluate the impact of urbanization on nearshore ecosystems. We measured physicochemical parameters and assessed bacterial community composition every two weeks for one year at two nearshore sites adjacent to watersheds with >70% urban land use and two nearshore sites adjacent to watersheds with >70% rural land use. Our results show that urbanization increases freshwater input and nutrient loading to nearshore ecosystems and profoundly alters the microbial community, overriding the natural seasonal succession observed at rural sites. At urban sites, we detected multiple bacterial species that are fecal indicators and human or marine organism pathogens. The altered physicochemical conditions and microbial communities at urban sites can contribute to the degradation of nearby coral reefs. Results highlight the importance of a "ridge-to-reef" management mindset, as restoring natural coastlines could buffer the impact of urbanization on the marine environment.

ecology↗

bioRxiv2023

Breakdown in seasonal dynamics of ant communities with land-cover change

Concerns about widespread human-induced declines in insect populations are mounting, yet little is known about how land-use change modifies the dynamics of insect communities, particularly in understudied biomes. Here, we examine how the seasonal patterns of ant activity--key drivers of terrestrial ecosystem functioning--vary with human-induced land cover change on a subtropical island landscape. Using trap captures sampled biweekly from a biodiversity monitoring network covering Okinawa Island, Japan, we processed 1.2 million individuals and reconstructed activity patterns within and across habitat types. Forest communities exhibited greater variability than those in more developed areas. Using time-series decomposition to deconstruct this pattern, we found that ant communities at sites with greater human development exhibited diminished seasonality, reduced synchrony, and higher stochasticity compared to those at sites with greater forest cover. Our results cannot be explained by variation in either regional or in situ temperature patterns, or by differences in species richness or composition among sites. We conclude that the breakdown of natural seasonal patterns of functionally key insect communities may comprise an important and underappreciated consequence of global environmental change that must be better understood across Earths biomes.

ecology↗

bioRxiv2023

Habitat degradation homogenizes ecological responses to typhoons across a subtropical island

Climate change is increasing the frequency, intensity, and duration of extreme weather events across the globe. Understanding the capacity for ecological communities to withstand and recover from such events is critical. Typhoons are extreme weather events that are expected to broadly homogenise ecological dynamics through structural damage to vegetation and longer-term effects of salinization. Given their unpredictable nature, monitoring ecological responses to typhoons is challenging, particularly for mobile animals such as birds. Here, we report spatially variable ecological responses to typhoons across terrestrial landscapes. Using a high temporal resolution passive acoustic monitoring network across 24 sites on the subtropical island of Okinawa, Japan, we found that typhoons elicit divergent ecological responses among Okinawas diverse terrestrial habitats, as indicated by increased spatial variability of biological sound production (biophony) and individual species detections. This suggests that soniferous communities are capable of a diversity of different responses to typhoons. That is, spatial insurance effects among local ecological communities provide resilience to typhoons at the landscape scale. Even though site-level typhoon impacts on soundscapes and bird detections were not particularly strong, monitoring at scale with high temporal resolution across a broad spatial extent nevertheless enabled detection of spatial heterogeneity in typhoon responses. Further, species-level responses mirrored those of acoustic indices, underscoring the utility of such indices for revealing insight into fundamental questions concerning disturbance and stability. Our findings demonstrate the significant potential of landscape-scale acoustic sensor networks to capture the understudied ecological impacts of unpredictable extreme weather events.

ecology↗