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Insects are the most diverse animal taxon on Earth and play a key role in ecosystem functioning. However, they are often neglected by ecological surveys owing to the difficulties involved in monitoring this small and hyper-diverse taxon. With technological advances in biomonitoring and analytical methods, these shortcomings may finally be addressed. Here, we performed passive acoustic monitoring at 141 sites (eight habitats) to investigate insect acoustic activity in the Viruá National Park, Brazil. We first describe the frequency range occupied by three soniferous insect groups (cicadas, crickets and katydids) to calculate the acoustic evenness index (AEI). Then, we assess how AEI varies spatially and temporally among habitat types, and finally we investigate the relationship between vegetation structure variables and AEI for each insect category. Overall, crickets occupied lower and narrower frequency bands than cicadas and katydids. AEI values varied among insect categories and across space and time. The highest acoustic activity occurred before sunrise and the lowest acoustic activity was recorded in pastures. Canopy cover was positively associated with cricket acoustic activity but not with katydids. Our findings contribute to a better understanding of the role of time, habitat and vegetation structure in shaping insect activity within diverse Amazonian ecosystems. This article is part of the theme issue 'Towards a toolkit for global insect biodiversity monitoring'. [ABSTRACT FROM AUTHOR]

Given the current rates of climate change, with associated shifts in herbivore population densities, understanding the role of different herbivores in ecosystem functioning is critical for predicting ecosystem responses. Here, we examined how migratory geese and resident, non‐migratory reindeer—two dominating yet functionally contrasting herbivores—control vegetation and ecosystem processes in rapidly warming Arctic tundra.We collected vegetation and ecosystem carbon (C) flux data at peak plant growing season in the two longest running, fully replicated herbivore removal experiments found in high‐Arctic Svalbard. Experiments had been set up independently in wet habitat utilised by barnacle geese Branta leucopsis in summer and in moist‐to‐dry habitat utilised by wild reindeer Rangifer tarandus platyrhynchus year‐round.Excluding geese induced vegetation state transitions from heavily grazed, moss‐dominated (only 4 g m−2 of live above‐ground vascular plant biomass) to ungrazed, graminoid‐dominated (60 g m−2 after 4‐year exclusion) and horsetail‐dominated (150 g m−2 after 15‐year exclusion) tundra. This caused large increases in vegetation C and nitrogen (N) pools, dead biomass and moss‐layer depth. Alterations in plant N concentration and CN ratio suggest overall slower plant community nutrient dynamics in the short‐term (4‐year) absence of geese. Long‐term (15‐year) goose removal quadrupled net ecosystem C sequestration (NEE) by increasing ecosystem photosynthesis more than ecosystem respiration (ER).Excluding reindeer for 21 years also produced detectable increases in live above‐ground vascular plant biomass (from 50 to 80 g m−2; without promoting vegetation state shifts), as well as in vegetation C and N pools, dead biomass, moss‐layer depth and ER. Yet, reindeer removal did not alter the chemistry of plants and soil or NEE.Synthesis. Although both herbivores were key drivers of ecosystem structure and function, the control exerted by geese in their main habitat (wet tundra) was much more pronounced than that exerted by reindeer in their main habitat (moist‐to‐dry tundra). Importantly, these herbivore effects are scale dependent, because geese are more spatially concentrated and thereby affect a smaller portion of the tundra landscape compared to reindeer. Our results highlight the substantial heterogeneity in how herbivores shape tundra vegetation and ecosystem processes, with implications for ongoing environmental change. [ABSTRACT FROM AUTHOR]

Understanding the response of species with differing life-history traits to habitat edges and habitat conversion helps predict their likelihood of persistence across changing landscape. In Brazil’s Atlantic Forest, we evaluated frog richness and abundance by breeding guild at four distances from the edge of a reserve: i) 200 m inside the forest, ii) 50 m inside the forest, iii) at the forest edge, and iv) 50 m inside three different converted habitats (coffee plantation, non-native Eucalyptus plantation, and abandoned pastures, hereafter matrix types). By sampling a dry and a wet season, we recorded 622 individual frogs representing 29 species, of which three were undescribed. Breeding guild (i.e. bromeliad, leaf-litter, and water-body breeders) was the most important variable explaining frog distributions in relation to edge effects and matrix types. Leaf-litter and bromeliad breeders decreased in richness and abundance from the forest interior toward the matrix habitats. Water-body breeders increased in richness toward the matrix and remained relatively stable in abundance across distances. Number of large trees (i.e. DBH > 15 cm) and bromeliads best explained frog richness and abundance across distances. Twenty species found in the interior of the forest were not found in any matrix habitat. Richness and abundance across breeding guilds were higher in the rainy season but frog distributions were similar across the four distances in the two seasons. Across matrix types, leaf-litter species primarily used Eucalyptus plantations, whereas water-body species primarily used coffee plantations. Bromeliad breeders were not found inside any matrix habitat. Our study highlights the importance of primary forest for bromeliad and leaf-litter breeders. We propose that water-body breeders use edge and matrix habitats to reach breeding habitats along the valleys. Including life-history characteristics, such as breeding guild, can improve predictions of frog distributions in response to edge effect and matrix types, and can guide more effective management and conservation actions. [ABSTRACT FROM AUTHOR]

Bromeliads are used by many frog species because of their capacity to accumulate rainwater. The bromeligenous frog, Phyllodytes luteolus (Yellow Heart-Tongued Frog), uses bromeliads for its entire life cycle including shelter, foraging, and reproduction. We evaluated the effect of plant morphometrics and the properties of water accumulated in bromeliads on the selection of these plants by P. luteolus. We sampled 103 bromeliads of which 41 were unoccupied and 62 were occupied by P. luteolus. Results suggest that bromeliad occupation by P. luteolus is nonrandom. We found that occupied plants were shorter in height, had a greater number of leaves, and had lower water conductivity than did unoccupied plants. Males were more likely to occupy plants with more leaves than were females. Plant selection may be related to the reproductive success of P. luteolus because frogs using plants with more leaves and lower conductivity may experience reductions in competition for space, predator encounters, and desiccation. Considering that illegal bromeliad harvesting threatens many bromeligenous frogs, improved understanding of bromeliad selection may determine which bromeliad species should be targeted for conservation to ensure the population viability of frogs. Bromélias são usadas por muitas espécies de anuros, devido à sua capacidade de acumular água da chuva. O anuro bromelígena Phyllodytes luteolus, usa bromélias para todo o seu ciclo de vida, incluindo abrigo, forrageamento e reprodução. Avaliamos o efeito da morfometria e as propriedades da água acumulada em bromélias na seleção dessas plantas por P. luteolus. Foram amostradas 103 bromélias, das quais 41 estavam desocupadas e 62 foram ocupadas por P. luteolus. Os resultados sugerem que a ocupação de bromélia por P. luteolus não é aleatória. Descobrimos que as plantas ocupadas eram menores, tinham um maior número de folhas, e tiveram menor condutividade da água que as plantas desocupadas. Os machos tendem a ocupar plantas com mais folhas do que as fêmeas. A seleção de bromélias pode estar relacionada com o sucesso reprodutivo de P. luteolus; por exemplo, os anuros que utilizam plantas com mais folhas e menor condutividade podem experimentar uma redução da concorrência por espaço, encontro predador, dessecação, porque mais axilas com água estarão disponíveis, resultando em um maior sucesso reprodutivo. Considerando-se que o extrativismo ilegal de bromélias ameaça muitos anuros bromelígenas, a melhor compreensão da seleção bromélia pode determinar as espécies de bromélias que devem ser priorizadas para a conservação a fim de assegurar a viabilidade da população de anuros. [ABSTRACT FROM AUTHOR]

Aim To determine whether there is evidence of changes in small mammals distributions and emergent metacommunity structure in the Atlantic Forest resulting from extensive habitat loss and fragmentation associated with anthropogenic activities. Location South American Atlantic Forest from northeastern Brazil to eastern Paraguay. Methods Using presence-absence data for non-volant small mammals, we analysed metacommunity structure for communities from 76 fragments distributed throughout Atlantic Forest. We evaluated coherence, range turnover and range boundary clumping for the entire non-volant small mammal assemblage, marsupials, rodents and sigmodontine rodents separately. β-diversity based on the multiplicative model was used to estimate the number of compartments (groups of sites with similar species composition) in Clementsian structures, and cluster analysis identified which sites formed compartments. Canonical correspondence analysis determined which environmental factors were associated with the gradients along which metacommunities were structured. Distance-decay analysis evaluated the spatial structure in small mammal and environmental data, and Mantel tests evaluated correlations between them. Results Rodent metacommunities had Clementsian structure, whereas marsupials had Gleasonian structure. Compartment locations for rodents were consistent with areas of endemism. Temperature seasonality was most associated with the gradients along which metacommunities were structured. Assemblage and environmental dissimilarity among sites had significant positive relationships with geographic distance. Main conclusions Compartment locations in Clementsian structures mirrored historical refugium locations and important vicariance events associated with large rivers. Despite extensive deforestation in Atlantic Forest, small mammal distributions are consistent with expectations based on historical biogeography, suggesting that anthropogenic activities have not yet greatly affected geographic distributions of emergent metacommunity structures. However, extinction debt associated with recent fragmentation and habitat loss may exist. Any effective conservation plan for large and fragmented biomes must consider areas of endemism to maintain regional biodiversity and maintain sufficiently large and connected fragments to facilitate rescue effects and minimize effects of extinction debt. [ABSTRACT FROM AUTHOR]

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Habitat fragmentation and invasive species often contribute to the decline of native taxa. Since the penetration of non-native species into natural habitat may be facilitated by habitat fragmentation, it is important to examine how these two factors interact. Previous research documented that, in contrast to most other arthropod taxa, spiders increased in density and morphospecies richness with decreasing fragment area and increasing fragment age (time since insularization) in urban habitat fragments in San Diego County, California, USA. We tested whether a specific mechanism, an increase in non-native species with fragmentation, is responsible for this pattern. We found that both native and non-native taxa contributed to the pattern. Abundance of native spiders per pitfall trap sample increased significantly with decreasing fragment size (i.e. a negative density–area relationship) and abundance of non-natives increased significantly with increasing fragment age. The proportion of non-native individuals also increased significantly with age. One non-native species, Oecobius navus, comprised the majority of non-native individuals (82.2%) and a significant proportion of total individuals (25.1%). Richness of spider families per sample (family density) increased with fragment age due to an increase in the occurrence of non-natives in older fragments, however, native family richness did not vary with age or area. Due to increasing dominance by non-native and some native families, family evenness declined with decreasing fragment size and increasing fragment age. Native and non-native abundance covaried positively arguing against strong negative interactions between the two groups. O. navus had a strong positive association with another common non-native arthropod, the Argentine ant ( Linepitheme humile), suggesting a possible direct interaction. In contrast, abundance of native spiders was negatively correlated with Argentine ant abundance. We hypothesize that fragmentation in this semiarid habitat increases productivity in smaller and older fragments enhancing the density of both native and non-native taxa. [ABSTRACT FROM AUTHOR]

Aim Eleutherodactylus coqui (commonly known as the coqui) is a frog species native to Puerto Rico and non-native in Hawaii. Despite its ecological and economic impacts, its potential range in Hawaii is unknown, making control and management efforts difficult. Here, we predicted the distribution potential of the coqui on the island of Hawaii. Location Puerto Rico and Hawaii. Methods We predicted its potential distribution in Hawaii using five biophysical variables derived from Moderate Resolution Imaging Spectroradiometer (MODIS) as predictors, presence/absence data collected from Puerto Rico and Hawaii and three classification methods - Classification Trees (CT), Random Forests (RF) and Support Vector Machines (SVM). Results Models developed separately using data from the native range and the invaded range predicted potential coqui habitats in Hawaii with high performance. Across the three classification methods, mean area under the ROC curve (AUC) was 0.75 for models trained using the native range data and 0.88 for models trained using the invaded range data. We achieved the highest AUC value of 0.90 using RF for models trained with invaded range data. Main conclusions Our results showed that the potential distribution of coquis on the island of Hawaii is much larger than its current distribution, with RF predicting up to 49% of the island as suitable coqui habitat. Predictions also show that most areas with an elevation between 0 and 2000 m are suitable coqui habitats, whereas the cool and dry high elevation areas beyond 2000 m elevation are unsuitable. Results show that MODIS-derived biophysical variables are capable of characterizing coqui habitats in Hawaii. [ABSTRACT FROM AUTHOR]

• Each of the eight habitats studied had unique and predictable soundscapes. • Statistical indices better distinguished habitat types than complexity indices. • The acoustic evenness index was strongly connected to changes in canopy cover. • Soundscapes can track changes in biodiversity across habitats in the Amazon. The rapidly developing field of ecoacoustics offers methods that can advance multi-taxa animal surveys at policy-relevant extents. While the field is promising, there remain foundational assumptions that need to be tested across different biomes before the methods can be applied widely. Here we test two of these assumptions in the Amazon: 1) that acoustic indices can be used to predict soundscapes of different habitat types, and 2) that acoustic indices are related to vegetation structure. We recorded soundscapes and collected vegetation data in 143 sites spanning six natural and two human-modified habitats in Viruá National Park, Roraima, Brazil. We grouped the eight habitats into three categories based on vegetative characteristics and flooding regime: open habitats, flooded-forests, and non-flooded forests. Thirteen acoustic indices were calculated from 92,283 one-minute recordings to describe the soundscapes of the habitats. We found that each habitat type had unique and predictable soundscapes. Random forest models were 74% accurate at predicting the eight habitats types and 87% accurate at predicting the three broader habitats categories. The most important acoustic indices to distinguish habitats were the third quartile and centroid. Canopy cover significantly affected 11 of 13 acoustic indices, and while other vegetation variables (e.g., shrub cover and number of trees) appeared in top models for some indices, their effects were not significant. The best indices linking soundscapes to vegetation structure were the acoustic evenness index and skewness, with canopy cover explaining 81% and 52% of the variance in these indices, respectively. These results expand our knowledge regarding which acoustic indices best connect changes in habitats to changes in soundscapes. These findings are particularly important for diverse ecosystems, like the Amazon, which are known to have complex soundscapes with sound-producing animals that are difficult to detect with traditional survey methods (e.g., visual transects). Ultimately, our results suggest that soundscapes are able to track changes in biodiversity levels across major habitat types of the Amazon. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]