Citizen science reveals widespread negative effects of roads on amphibian distributions

Landscape structure is important for shaping the abundance and distribution of amphibians, but prior studies of landscape effects have been species or ecosystem-specific. Using a large-scale, citizen science-generated database, we examined the effects of habitat composition, road disturbance, and habitat split (i.e. the isolation of wetland from forest by intervening land use) on the distribution and richness of frogs and toads in the eastern and central United States. Undergraduates from nine biology and environmental science courses collated occupancy data and characterized landscape structure at 1617 sampling locations from the North American Amphibian Monitoring Program. Our analysis revealed that anuran species richness and individual species distributions were consistently constrained by both road density and traffic volume. In contrast, developed land around wetlands had small, or even positive effects on anuran species richness and distributions after controlling for road effects. Effects of upland habitat composition varied among species, and habitat split had only weak effects on species richness or individual species distributions. Mechanisms underlying road effects on amphibians involve direct mortality, behavioral barriers to movement, and reduction in the quality of roadside habitats. Our results suggest that the negative effects of roads on amphibians occur across broad geographic regions, affecting even common species, and they underscore the importance of developing effective strategies to mitigate the impacts of roads on amphibian populations

A Severe Red Tide (Tampa Bay, 2005) Causes an Anomalous Decrease in Biological Sound

Although harmful algal blooms (HABs) are known to cause morbidity and mortality in marine organisms, their sublethal effects are poorly understood. The purpose of this study was to compare ambient noise levels during a severe HAB event in Tampa Bay, Florida, to those during non-HAB periods. Passive acoustic monitoring was conducted using bottom-mounted autonomous acoustic recorders during a severe HAB in summer 2005, and in summers 2006, 2011 and 2012 (non-severe HAB years). Ambient noise levels were significantly higher during the non-HAB years due to an abundance of snapping shrimp (Alpheidae) sounds and fish chorusing. The difference of sound intensity between the study years is most likely attributable to effects of the HAB on the abundance and/or behaviour of fish and snapping shrimp as a result of mortality and stress-induced behavioural modifications

Adult female-calf acoustic communication signals in migrating east Australian humpback whales

Humpback whale (Megaptera novaeangliae) calf survival during migration is dependent upon them maintaining contact with their mothers, and acoustics likely plays a significant role in this. Here, we analysed calls (n = 255) produced by migrating humpback whale adult female-calf pairs (n = 15) off the east coast of Australia. First, we identified nine common call types that were then quantitatively separated into two distinct clusters. One cluster contained calls that were considerably longer in duration, lower in frequency, and narrower in bandwidth than those in the second cluster. These are proposed to have been produced by the adult females and calves, respectively. We then compared acoustic features within presumed age class. Minimum, peak, and maximum frequencies were significantly different across both adult females and calves (Kruskal-Wallis, p < 0.05), suggesting that their calls encode socially relevant information regarding physical signaller attributes (i.e. age and body size). This study established a baseline adult female-calf call repertoire produced during the migration of east Australian humpback whales. Potential vocal masking from anthropogenic noise is of particular concern for communications between adult females and their calves, as it may put calves at risk of becoming separated from their mothers

A severe red tide (Tampa Bay, 2005) causes an anomalous decrease in biological sound

Although harmful algal blooms (HABs) are known to cause morbidity and mortality in marine organisms, their sublethal effects are poorly understood. The purpose of this study was to compare ambient noise levels during a severe HAB event in Tampa Bay, Florida, to those during non-HAB periods. Passive acoustic monitoring was conducted using bottommounted autonomous acoustic recorders during a severe HAB in summer 2005, and in summers 2006, 2011 and 2012 (nonsevere HAB years). Ambient noise levels were significantly higher during the non-HAB years due to an abundance of snapping shrimp (Alpheidae) sounds and fish chorusing. The difference of sound intensity between the study years is most likely attributable to effects of the HAB on the abundance and/or behaviour of fish and snapping shrimp as a result of mortality and stress-induced behavioural modifications