Rare bird forecast: A combined approach using a long-term dataset of an Arctic seabird and a numerical weather prediction model.

Wildlife observation is a popular activity, and sightings of rare or difficult-to-find animals are often highly desired. However, predicting the sighting probabilities of these animals is a challenge for many observers, and it may only be possible by limited experts with intimate knowledge and skills. To tackle this difficulty, we developed user-friendly forecast systems of the daily observation probabilities of a rare Arctic seabird (Ross's Gull Rhodostethia rosea) in a coastal area in northern Japan. Using a dataset gathered during 16 successive winters, we applied a machine learning technique of self-organizing maps and explored how days with gull sightings were related to the meteorological pressure patterns over the Sea of Okhotsk (Method A). We also built a regression model that explains the relationship between gull sightings and local-scale environmental factors (Method B). We then applied these methods with the operational global numerical weather prediction model (a computer simulation application about the fluid dynamics of Earth's atmosphere) to forecast the daily observation probabilities of our target. Method A demonstrated a strong dependence of gull sightings on the 16 representative weather patterns and forecasted stepwise observation probabilities ranging from 0% to 85.7%. Method B also showed that the strength of the northerly wind and the advancement of the season explained gull sightings and forecasted continuous observation probabilities ranging from 0% to 95.5%. Applying these two methods with the operational global numerical weather prediction model successfully forecasted the varied observation probabilities of Ross's Gull from 1 to 5 days ahead from November to February. A 2-year follow-up observation also validated both forecast systems to be effective for successful observation, especially when both systems forecasted higher observation probabilities. The developed forecast systems would therefore allow cost-effective animal observation and may facilitate a better experience for a variety of wildlife observers.

Noise pollution alters the diet composition of invertebrate consumers both in and beyond a noise-exposed grassland ecosystem.

Anthropogenic noise is ubiquitous globally. However, we know little about how the impacts of noise alter fundamental ecosystem properties, such as resource consumption by invertebrate consumers. Using experimental noise manipulation and faecal DNA metabarcoding, we assessed how the direct and cross-trophic indirect effects of noise altered the dietary richness and specializations of omnivorous grasshoppers in a grassland ecosystem. We found that the experimental noise treatment expanded grasshoppers' dietary richness and resulted in dietary generalizations in both noise-exposed and adjacent relatively quieter areas. Unexpectedly, however, these dietary changes were primarily explained by the direct effect of noise not only in the noise-exposed areas but also in the adjacent quieter areas and were relaxed by indirect effects of noise such as reduced birds and predation risk and increased grasshoppers. Our work suggests that noise pollution can be key in explaining the variation of invertebrate consumers' diets across a gradient of noise-exposed environments.

Intentional release of native species undermines ecological stability.

The massive release of captive-bred native species ("intentional release") is a pervasive method to enhance wild populations of commercial and recreational species. However, such external inputs may disrupt the sensitive species interactions that allow competing species to coexist, potentially compromising long-term community stability. Here, we use theory and long-term data of stream fish communities to show that intentional release destabilizes community dynamics with limited demographic benefit to the enhanced species. Our theory predicted that intentional release intensifies interspecific competition, facilitating the competitive exclusion of unenhanced species that otherwise stably coexist. In parallel, the excessive input of captive-bred individuals suppressed the natural recruitment of the enhanced species via intensified within-species competition. Consequently, the ecological community with the intentional release is predicted to show reduced community density with unstable temporal dynamics. Consistent with this prediction, stream fish communities showed greater temporal fluctuations and fewer taxonomic richness in rivers with the intensive release of hatchery salmon-a major fishery resource worldwide. Our findings alarm that the current overreliance on intentional release may accelerate global biodiversity loss with undesired consequences for the provisioning of ecosystem services.

Quantifying the impacts of 166 years of land cover change on lowland bird communities.

Land cover change for agriculture is thought to be a major threat to global biodiversity. However, its ecological impact has rarely been quantified in the Northern Hemisphere, as broad-scale conversion to farmland mainly occurred until the 1400s-1700s in the region, limiting the availability of sufficient data. The Ishikari Lowland in Hokkaido, Japan, offers an excellent opportunity to address this issue, as hunter-gatherer lifestyles dominated this region until the mid-nineteenth century and land cover maps are available for the period of land cover changes (i.e. 1850-2016). Using these maps and a hierarchical community model of relationships between breeding bird abundance and land cover types, we estimated that broad-scale land cover change over a 166-year period was associated with more than 70% decline in both potential species richness and abundance of avian communities. We estimated that the abundance of wetland and forest species declined by greater than 88%, whereas that of bare-ground/farmland species increased by more than 50%. Our results suggest that broad-scale land cover change for agriculture has led to drastic reductions in wetland and forest species and promoted changes in community composition in large parts of the Northern Hemisphere. This study provides potential baseline information that could inform future conservation policies.

Population-specific association of Clock gene polymorphism with annual cycle timing in stonechats.

Timing is essential for survival and reproduction of organisms across the tree of life. The core circadian clock gene Clk is involved in the regulation of annual timing events and shows highly conserved sequence homology across vertebrates except for one variable region of poly-glutamine repeats. Clk genotype varies in some species with latitude, seasonal timing and migration. However, findings are inconsistent, difficult to disentangle from environmental responses, and biased towards high latitudes. Here we combine field data with a common-garden experiment to study associations of Clk polymorphism with latitude, migration and annual-cycle timing within the stonechat species complex across its trans-equatorial distribution range. Our dataset includes 950 records from 717 individuals from nine populations with diverse migratory strategies. Gene diversity was lowest in resident African and Canary Island populations and increased with latitude, independently of migration distance. Repeat length and annual-cycle timing was linked in a population-specific way. Specifically, equatorial African stonechats showed delayed timing with longer repeat length for all annual-cycle stages. Our data suggest that at low latitudes with nearly constant photoperiod, Clk genotype might orchestrate a range of consistent, individual chronotypes. In contrast, the influence of Clk on annual-cycle timing at higher latitudes might be mediated by its interactions with genes involved in (circadian) photoperiodic pathways.

Sensory pollutants alter bird phenology and fitness across a continent.

Expansion of anthropogenic noise and night lighting across our planet1,2 is of increasing conservation concern3-6. Despite growing knowledge of physiological and behavioural responses to these stimuli from single-species and local-scale studies, whether these pollutants affect fitness is less clear, as is how and why species vary in their sensitivity to these anthropic stressors. Here we leverage a large citizen science dataset paired with high-resolution noise and light data from across the contiguous United States to assess how these stimuli affect reproductive success in 142 bird species. We find responses to both sensory pollutants linked to the functional traits and habitat affiliations of species. For example, overall nest success was negatively correlated with noise among birds in closed environments. Species-specific changes in reproductive timing and hatching success in response to noise exposure were explained by vocalization frequency, nesting location and diet. Additionally, increased light-gathering ability of species' eyes was associated with stronger advancements in reproductive timing in response to light exposure, potentially creating phenological mismatches7. Unexpectedly, better light-gathering ability was linked to reduced clutch failure and increased overall nest success in response to light exposure, raising important questions about how responses to sensory pollutants counteract or exacerbate responses to other aspects of global change, such as climate warming. These findings demonstrate that anthropogenic noise and light can substantially affect breeding bird phenology and fitness, and underscore the need to consider sensory pollutants alongside traditional dimensions of the environment that typically inform biodiversity conservation.

Direct and indirect effects of noise pollution alter biological communities in and near noise-exposed environments.

Noise pollution is pervasive across every ecosystem on Earth. Although decades of research have documented a variety of negative impacts of noise to organisms, key gaps remain, such as how noise affects different taxa within a biological community and how effects of noise propagate across space. We experimentally applied traffic noise pollution to multiple roadless areas and quantified the impacts of noise on birds, grasshoppers and odonates. We show that acoustically oriented birds have reduced species richness and abundance and different community compositions in experimentally noise-exposed areas relative to comparable quiet locations. We also found both acoustically oriented grasshoppers and odonates without acoustic receptors to have reduced species richness and/or abundance in relatively quiet areas that abut noise-exposed areas. These results suggest that noise pollution not only affects acoustically oriented animals, but that noise may reverberate through biological communities through indirect effects to those with no clear links to the acoustic realm, even in adjacent quiet environments.

Seasonality in spatial distribution: Climate and land use have contrasting effects on the species richness of breeding and wintering birds.

AIM: Many studies have examined large-scale distributions of various taxa and their drivers, emphasizing the importance of climate, topography, and land use. Most studies have dealt with distributions over a single season or annually without considering seasonality. However, animal distributions and their drivers can differ among seasons because many animals migrate to suitable climates and areas with abundant prey resources. We aim to clarify seasonality in bird distributions and their drivers. LOCATION: Japan. METHODS: We examined the effects of climate (annual mean temperature, snow depth), topography (elevation), and land use (extent of surrounding habitat) on bird species richness, in the breeding and wintering seasons separately, using nationwide data (254 forest and 43 grassland sites, respectively). We separately analyzed the species richness of all species, residents, short-, and long-distance migrants in forests and grasslands. RESULTS: In the breeding season, the annual mean temperature negatively affected all groups (except for forest and grassland residents), and the extent of surrounding habitat positively affected many groups. By contrast, in the wintering season, temperature positively affected all groups (except for forest residents), and the extent of surrounding habitat positively affected only grassland long-distance migrants. In both seasons, the species richness of forest and grassland residents was high in regions of moderate and high temperature, respectively. Moreover, snow depth negatively affected all forest groups in the wintering season. Mapping expected species richness suggested that regions with different climates served as habitats for different groups during different seasons. MAIN CONCLUSIONS: All regions were important bird habitats depending on the season, reflecting the contrasting effects of temperature across seasons. In the breeding season, surrounding land use was also an important driver. To understand the seasonal role that each region and environment plays in maintaining species/communities, a large-scale study considering both environmental seasonality and species distribution is needed.

Traffic noise reduces foraging efficiency in wild owls.

Anthropogenic noise has been increasing globally. Laboratory experiments suggest that noise disrupts foraging behavior across a range of species, but to reveal the full impacts of noise, we must examine the impacts of noise on foraging behavior among species in the wild. Owls are widespread nocturnal top predators and use prey rustling sounds for localizing prey when hunting. We conducted field experiments to examine the effect of traffic noise on owls' ability to detect prey. Results suggest that foraging efficiency declines with increasing traffic noise levels due to acoustic masking and/or distraction and aversion to traffic noise. Moreover, we estimate that effects of traffic noise on owls' ability to detect prey reach >120 m from a road, which is larger than the distance estimated from captive studies with bats. Our study provides the first evidence that noise reduces foraging efficiency in wild animals, and highlights the possible pervasive impacts of noise.