Estimates Of Species Abundance Research Articles

Can nuclear aquatic environmental DNA be a genetic marker for the accurate estimation of species abundance?

Environmental DNA (eDNA) analysis is a promising tool for the sensitive and effective monitoring of species distribution and abundance. Traditional eDNA analysis has targeted mitochondrial DNA (mtDNA) fragments due to their abundance in cells; however, the quantification may vary depending on cell type and physiology. Conversely, some recent eDNA studies have targeted multi-copy nuclear DNA (nuDNA) fragments, such as ribosomal RNA genes, in water, and reported a higher detectability and more rapid degradation than mitochondrial eDNA (mt-eDNA). These properties suggest that nuclear eDNA (nu-eDNA) may be useful for the accurate estimation of species abundance relative to mt-eDNA, but which remains unclear. In this study, we compiled previous studies and re-analyzed the relationships between mt- and nu-eDNA concentration and species abundance by comparing the R2 values of the linear regression. We then performed an aquarium experiment using zebrafish (Danio rerio) to compare the relationships across genetic regions, including single-copy nuDNA. We found more accurate relationships between multi-copy nu-eDNA and species abundance than mt-eDNA in these datasets, although the difference was not significant upon weighted-averaging the R2 values. Moreover, we compared the decay rate constants of zebrafish eDNA across genetic regions and found that multi-copy nu-eDNA degraded faster than mt-eDNA under pH 7, implying a quick turnover of multi-copy nu-eDNA in the field. Although further empirical studies of nu-eDNA applications are necessary to support our findings, this study provides the groundwork for improving the estimation accuracy of species abundance via eDNA analysis.

Robustness of fecal DNA spatial capture‐recapture to clustered space‐use by tule elk

AbstractSpatially explicit capture‐recapture (SCR) approaches using noninvasive fecal DNA (fDNA) are applied increasingly to obtain statistically robust abundance estimates for various wildlife species. But SCR has not been widely used for more gregarious species, such as elk (Cervus canadensis). Because of their heterogeneous use of the landscape and grouping behavior, elk present novel challenges to sampling efficiency and statistical assumptions. We employed fDNA SCR and a stratified random sampling approach to estimate abundance in 3 northern California tule elk (C. c. nannodes) populations concurrent with global positioning system (GPS)‐telemetry monitoring of 66 elk (32 male, 34 female) in Colusa and Lake counties, California, USA, during June–August 2017–2019. We collected 1,616 fecal pellet groups from the 3 populations, resulting in 1,002 fDNA genotypes (≥19 microsatellite loci, 1 sex marker) of 425 unique individuals. Based on SCR estimates from a model incorporating both sexes, elk density ranged from 0.31 (95% CI = 0.17–0.55) elk/km2to 1.7 (95% CI = 1.3–2.2) elk/km2, translating approximately to 650 individuals (evenly split between sexes) among the 3 populations. Independent telemetry data from concurrently tracked individuals indicated that activity centers of females, but not males, were clustered on the landscape. This finding was corroborated using fDNA to infer activity centers. Comparison of SCR estimates to non‐spatial estimates using physically captured individuals suggested that combined‐sex SCR models were robust to spatial clustering of females in all 3 populations. Additionally, single‐sex models were robust to female clustering in the 2 populations with multiple female groups, but not in Lake Pillsbury, where all females effectively shared a single activity center. In that case, the estimate of female abundance was deemed an overestimate. Thus, results indicate that SCR was robust to gregariousness in elk in all but the most extreme cases of clustering (single‐sex female estimation when all individuals share a single activity center), and that the inclusion of both sexes was sufficient to offset biases stemming from aggregation of females in all cases. Altogether, our findings suggest that SCR methods can be gainfully applied to socially gregarious ungulates such as elk.

Monitoring fish using imaging sonar: Capacity, challenges and future perspective

AbstractThe demand for fish products, which provide crucial protein for humans, is rising as the global population grows. In contrast, fish stock is declining due to human activity, environmental changes and overfishing. Fish monitoring provides valuable support data for effective fishery management and ecosystem conservation. The common monitoring methods are based on manual sampling, which is time‐consuming, laborious and intrusive. Imaging sonar is a hydroacoustic system that produces acoustic images similar to optical images by transmitting and receiving sound waves, allowing for in situ monitoring of fish non‐intrusively in the dark and turbid water environments where optical cameras are limited. In the last decade, imaging sonar, especially high frequency multibeam forward‐looking sonar and side‐scan sonar, has been widely used in fish monitoring. We reviewed the literature from the previous decade on the use of these two types of imaging sonar in fish species identification, abundance estimation, length measurement and behaviour analysis, as well as the sonar imagery processing concerning fish. The review results show that these imaging sonars are efficient and effective tools for fish monitoring in complex environments. The challenges include (1) the recognition of small fish forming dense aggregations; (2) species identification, which limits their use in species‐specific studies; (3) time‐consuming massive data processing. Therefore, advanced algorithms for sonar imagery processing and integrations with other sampling technologies are needed for future development.

Opportunities and risks in the use of drones for studying animal behaviour

Abstract In the last decade, drones have become an affordable technology offering highly mobile aerial platforms that can carry a range of sensory equipment into hitherto uncharted areas. Drones have thus become a widely applicable tool for surveying animal populations and habitats to assist conservation efforts or to study the behavioural ecology of species by monitoring individual and group behaviour. Here, we review current applications for drone surveys and the potential of recently developed computer algorithms for automatic species detection and individual tracking in drone footage. We further review which factors are reportedly associated with animal disturbance during drone presentations and how drones may be used to study anti‐predator behaviour. Drone surveys of species and their environments allow scientists to create digital terrain models of habitats, estimate species abundance, monitor individual behaviour and study the composition, spatial organization and movement of groups. As drones can influence the behaviour of many bird and mammal species directly, they also provide an experimental tool to study animal responses to novel situations, including the drone itself. We conclude that the combined use of drones and automated detection software can assist population estimates and opens new possibilities to study individual and collective behaviour. With regard to drone‐related disturbance and their potential use as predator models, we recommend to interpret results against the background of population‐specific predation pressure and sources of anthropogenic disturbance.

Testing the effectiveness of environmental DNA (eDNA) to quantify larval amphibian abundance

AbstractEnvironmental DNA (eDNA) monitoring is rapidly becoming an established approach for detecting the presence of aquatic organisms and may also be useful for indexing or estimating species abundance. However, the link between eDNA concentration and abundance of individuals (i.e., density or biomass) remains tenuous and may vary widely across species and environmental conditions. We investigated the relationship between eDNA concentration and abundance in two common and closely related amphibians in eastern North America, the wood frog (Rana sylvatica), and northern leopard frog (R. pipiens). We manipulated tadpole density in 80‐L mesocosms and documented the relationship between tadpole density and biomass and eDNA concentration through time. The two species differed in the amount of detectible genetic material produced, despite having comparable biomass. Concentration of eDNA increased with tadpole numbers and was primarily correlated with tadpole density in wood frogs and biomass in leopard frogs. eDNA degradation rates were rapid and comparable between species, with tadpoles becoming indetectable within 5 days post‐removal from the mesocosm, irrespective of tadpole density. Overall, our findings support that eDNA concentration has potential for tracking amphibian abundance in wetlands, but that indices of abundance are likely to be coarse and species‐specific calibration will be required. Future research should address how biotic and abiotic factors influence eDNA production, degradation, and recovery across species and through time before relying on eDNA for monitoring amphibian abundance in nature.

Analysis of riparian vegetation of a recreation site in Jeli, Kelantan

Lata Keding is recognised as one of the recreational areas in Jeli, Kelantan. It has the function to protect the riparian plant habitats but it is potentially threatened by anthropogenic activities. This study was aimed to determine riparian plant species diversity and estimate species abundance of riparian plant vegetation at Lata Keding, Jeli, Kelantan. The line transect method was used to collect vegetation data. The line transect was established about one km long and each plant species that exist within 3 m up to 5 m from the river bank were recorded. A total of 2389 individuals belonging to 36 families and 49 species were recorded in the study area. Species diversity with Shannon-Wiener Diversity Index (H’) with a value of 2.89, while Hmax was 3.99 and Evenness Index (EH) value was 0.72 for the study area. The most dominant families recorded with a high diversity of plant species were Family Melastomataceae (5 species), Asteraceae (5 species) and Fabaceae (3 species). A total of 529 individuals of Clidemia hirta from Family Melastomataceae was recorded as the most dominant species. Thirty-six species are classified as Not Evaluated (NE), six species classified as Least Concern (LC), four species as Near Threatened (NT), two species Vulnerable (VU) and one species listed as Critically Endangered (CR).

Dynamic Habitat Models Reflect Interannual Movement of Cetaceans Within the California Current Ecosystem

The distribution of wide-ranging cetacean species often cross national or jurisdictional boundaries, which creates challenges for monitoring populations and managing anthropogenic impacts, especially if data are only available for a portion of the species’ range. Many species found off the U.S. West Coast are known to have continuous distributions into Mexican waters, with highly variable abundance within the U.S. portion of their range. This has contributed to annual variability in design-based abundance estimates from systematic shipboard surveys off the U.S. West Coast, particularly for the abundance of warm temperate species such as striped dolphin,Stenella coeruleoalba, which increases off California during warm-water conditions and decreases during cool-water conditions. Species distribution models (SDMs) can accurately describe shifts in cetacean distribution caused by changing environmental conditions, and are increasingly used for marine species management. However, until recently, data from waters off the Baja California peninsula, México, have not been available for modeling species ranges that span from Baja California to the U.S. West Coast. In this study, we combined data from 1992–2018 shipboard surveys to develop SDMs off the Pacific Coast of Baja California for ten taxonomically diverse cetaceans. We used a Generalized Additive Modeling framework to develop SDMs based on line-transect surveys and dynamic habitat variables from the Hybrid Coordinate Ocean Model (HYCOM). Models were developed for ten species: long- and short-beaked common dolphins (Delphinus delphis delphis and D. d. bairdii), Risso’s dolphin (Grampus griseus), Pacific white-sided dolphin (Lagenorhynchus obliquidens), striped dolphin, common bottlenose dolphin (Tursiops truncatus), sperm whale (Physeter macrocephalus), blue whale (Balaenoptera musculus), fin whale (B. physalus), and humpback whale (Megaptera novaeangliae). The SDMs provide the first fine-scale (approximately 9 x 9 km grid) estimates of average species density and abundance, including spatially-explicit measures of uncertainty, for waters off the Baja California peninsula. Results provide novel insights into cetacean ecology in this region as well as quantitative spatial data for the assessment and mitigation of anthropogenic impacts.

Using quantitative eDNA analyses to accurately estimate American bullfrog abundance and to evaluate management efficacy

AbstractBiological invasions contribute now more than ever to the global homogenization of fauna and flora. Large‐scale monitoring programs are, therefore, needed to detect incipient invasions and to evaluate management interventions. As conventional monitoring methods are constrained by large costs, environmental DNA (eDNA)‐based methods are increasingly recognized as valuable monitoring tools. However, accurately estimating species abundance from eDNA concentrations in natural systems remains challenging and consequently hinders their integration in management applications. Here, we used droplet digital PCR (ddPCR) in eDNA surveys to estimate the abundance of invasive American bullfrogs (Lithobates catesbeianus). We first introduced bullfrog tadpoles in natural ponds to assess the relationship between abundances and eDNA concentrations under field conditions. Next, we combined eDNA sampling with fyke netting in naturally colonized ponds to investigate whether bullfrog eDNA concentrations can estimate bullfrog capture success and conventional abundance measures obtained via depletion sampling. Finally, we evaluated eradication measures by comparing bullfrog eDNA concentrations before and after fyke netting. We found a strong linear relationship between the numbers of introduced tadpoles and eDNA concentrations (r2 = 0.988). Bullfrog eDNA concentrations were not only linearly related to the catch‐per‐unit‐effort (r2 = 0.739), but also to conventional abundance estimates (r2 = 0.716), particularly when eDNA concentrations were standardized for pond area (r2 = 0.834) and volume (r2 = 0.888). Bullfrog tadpoles were only captured when eDNA concentrations exceeded 1.5 copies µl−1, indicating that quantitative eDNA analyses enable the localization of breeding ponds. We found a significant reduction in eDNA concentrations after fyke netting proportional to the number of captured bullfrogs. These results demonstrate that eDNA quantification is a reliable tool that accurately estimates bullfrog abundance in natural lentic systems. We show that quantitative eDNA analyses can complement the toolbox of natural resource managers and facilitate the coordination of eradication campaigns targeting alien invasive species.

Uncovering forest dynamics using historical forest inventory data and Landsat time series

While many countries regularly produce timely and accurate estimates for a range of forest attributes through national forest inventory programs, many have access to no such inventory or their inventory is discontinuous in space and time, such as a sample-based approach in Ukraine limited to two regional (Ivano-Frankivsk and Sumy) inventories conducted in 2008–2015 at a total area of 37,700 ha. This study addresses the extent to which limited historical forest inventory data may facilitate forest mapping efforts using dense Landsat time series (LTS) and mapping techniques (i.e., classification and imputation) to predict multiyear forest dynamics. We used the Continuous Change Detection and Classification (CCDC) segmentation approach to extract inter- and intra-annual trends in LTS and utilized these fitted trends as covariates in further modeling. We developed random forest (RF) classification models for forest mapping based on field data collection and LTS, and then generated yearly forest maps for 1990–2020. The RF model accuracies were high for both producer’s and user’s accuracy (>0.93 ± 0.04). Based on yearly forest dynamics, we detected an increasing trend in forest loss during 2000–2010 and 2010–2020 in our regions. We used the gradient nearest neighbor (GNN) method to generate species presence (basal area (BA) ≥ 1.0 m2 ha−1) and growing stock volume (GSV) maps at the 30-m pixel level. Our nearest neighbor imputation models achieved better accuracies (Cohen’s kappa > 0.4) for species that are prevalent within regions, occupy distinct geographical areas, and have higher plot BA abundance. To obtain estimates of species abundance with higher R2, we used the GNN model with k = 3 nearest neighbors. Aggregating species based on similar environmental niche resulted in greater R2 values of BA that varied within two regions from low (0.129 and 0.416) for a group of hardwood deciduous species to high (0.531 and 0.712) for coniferous species. The accuracy was systematically better at 5-km hexagonal level, thus we recommend using the maps at coarser aggregations. The study showed that forests accumulated more GSV in 1990–2000, albeit higher rates of GSV loss were observed during the two last decades. We attribute the spatial and temporal character of forest change to forestry activities in the past, the current age structure of forests, and afforestation of abandoned farmlands. We are aware that forecasting performance of the nearest neighbor imputation approach merits more detailed consideration as new forest inventory data are available.

Habitat Preference and Distribution of Crickets (Orthoptera; Gryllidae) in Western Kenya

Information for identifying biodiversity hotspots for species conservation involves the estimation of species abundance, distribution and habitat preference. Adult crickets were sampled from four Agro ecological zones (AEZ) in Western Kenya during the months of June 2020 to January 2021 and identified morphologically. Thirteen descriptive variables associated with topography, water, and greenness, were used to create a habitat distribution model. Akaike information criteria (AIC) was applied to estimate the habitat preference for each cricket species. A total of 3535 crickets were recovered, comprising 3335 insects belonging to 6 identified species and 200 others. Gryllus bimaculatus had the highest relative abundance of 28.43% while Brachytrupes membranaceus recorded the least abundance of 4.67%. The diversity indices showed that natural vegetation had the highest diversity index (H’= 0.361) and dorminance (D = 0.194). Areas with human settlement had the least diversity index and dominance (H’= 0.231) and (d = 0.010) respectively. The results indicate that the cricket species can be classified into three groups, Group I ( Acheta domesticus , and Diestrammena asynamora ) which preferred areas near settlement, Group II ( Scapsipedus icipe , Gryllus bimaculatus , and Brachytrupes membranaceus ) that preferred fields and grasses and Group III ( Gryllotalpa africana ) that preferred wet lands. This study concludes that the most preferred habitats are natural vegetation, areas near water bodies, having high shelter density and away from human settlement. Conservation management targeting habitats for this edible insect should form part of integrated species conservation measures focusing especially on the biodiversity hotspots. Keywords: Abundance, Crickets, Diversity, Distribution, Habitat preference DOI: 10.7176/JBAH/12-6-04 Publication date: March 31 st 2022

Metabarcoding of canopy arthropods reveals negative impacts of forestry insecticides on community structure across multiple taxa

Abstract Insecticides used to combat outbreaks of forest defoliators can adversely affect non‐target arthropods. Forestry insecticides typically suppress Lepidoptera larvae which are the cornerstone of the canopy community of deciduous oak forests. The abrupt removal of this dominant component of the food web could have far‐reaching implications for forest ecosystems, yet it is rarely investigated in practice owing to several methodological shortcomings. The taxonomic impediment and the biased nature of arthropod sampling techniques particularly impede the assessment of insecticide impacts on diverse communities. To tackle this issue, we propose an experimental approach combining sampling by pyrethrum knockdown and species determination via DNA metabarcoding, using community subsampling to derive estimates of species abundances. We applied this protocol to investigate the short‐term effects of the insecticides diflubenzuron (DFB) and Bacillus thuringiensis var. kurstaki (BTK) on canopy‐dwelling arthropod communities in German oak woodlands. Our approach allowed us to detect most of the diversity and integrate species abundances in our analyses. By classifying arthropod species into assemblages based on their expected sensitivity rather than coarse taxonomic groupings, we could unveil substantial effects of DFB across multiple taxa 5 weeks after application. Although strong effects on single species appear related to direct toxicity, substantial impacts of DFB on parasitoids and xylophagous beetles suggest that anti‐defoliator treatments can have previously unsuspected indirect effects on some components of forest arthropod communities. The impacts of BTK on community structure were consistent with that of DFB though much weaker. Synthesis and applications. Comparing diversity patterns in the arthropod communities of sprayed and unsprayed oak canopies, our results show that selective insecticides can alter species diversity in presumably non‐sensitive taxa. Even though the ecological significance of these impacts has yet to be assessed in an operational setting, their existence calls for increased regulatory scrutiny on indirect effects. As community approaches become more attainable with the rapid development of DNA metabarcoding, we suggest the inclusion of community‐level end points as regulatory requirements for the approval of forest‐use insecticides.

A novel sampling approach to estimating abundance of low‐density and observable species

AbstractInformative species abundance estimates are critical for guiding decisions around the conservation and management of ecological systems. There exist many methods for estimating abundance of frequently encountered species and populations with uniquely identifiable individuals. However, for wildlife populations with unmarked individuals that occur at low densities, there exist a variety of behaviors and characteristics that make effectively surveying and sampling challenging or uninformative. Examples of challenging characteristics include the elusive behaviors of low‐density species that occur in complex and rugged terrain. Such characteristics make detection difficult and surveys expensive, dangerous, and potentially biased. To address these challenges, we used a common, non‐invasive field survey method combined with a probability‐based study design and frequently utilized statistical model to estimate abundance of an unmarked mountain goat population in eastern Idaho. We developed a novel data analysis approach using an N‐mixture model that, together with spatially balanced random sampling and a double‐observer field data collection method, directly solves the problem of approximating statistical assumptions, including population closure. We demonstrate that a probability‐based sampling design not only is feasible, but also is important for estimating population parameters for unmarked and low‐density species. With this approach, we present a procedure that offers unbiased abundance estimates, empowering managers to track low‐density species’ population trends across time.

Evaluation of camera trap-based abundance estimators for unmarkedpopulations.

Estimates of species abundance are critical to understand population processes and to assess and select management actions. However, capturing and marking individuals for abundance estimation, while providing robust information, can be economically and logistically prohibitive, particularly for species with cryptic behavior. Camera traps can be used to collect data at temporal and spatial scales necessary for estimating abundance, but the use of camera traps comes with limitations when target species are not uniquely identifiable (i.e., "unmarked"). Abundance estimation is particularly useful in the management of invasive species, with herpetofauna being recognized as some of the most pervasive and detrimental invasive vertebrate species. However, the use of camera traps for these taxa presents additional challenges with relevancy across multiple taxa. It is often necessary to use lures to attract animals in order to obtain sufficient observations, yet lure attraction can influence species' landscape use and potentially induce bias in abundance estimators. We investigated these challenges and assessed the feasibility of obtaining reliable abundance estimates using camera-trapping data on a population of invasive brown treesnakes (Boiga irregularis) in Guam. Data were collected using camera traps in an enclosed area where snakes were subject to high-intensity capture-recapture effort, resulting in presumed abundance of 116 snakes (density=23/ha). We then applied spatial count, random encounter and staying time, space to event, and instantaneous sampling estimators to photo-capture data to estimate abundance and compared estimates to our presumed abundance. We found that all estimators for unmarked populations performed poorly, with inaccurate or imprecise abundance estimates that limit their usefulness for management in this system. We further investigated the sensitivity of these estimators to the use of lures (i.e., violating the assumption that animal behavior is unchanged by sampling) and camera density in a simulation study. Increasing the effective distances of a lure (i.e., lure attraction) and camera density both resulted in biased abundance estimates. Each estimator rarely recovered truth or suffered from convergence issues. Our results indicate that, when limited to unmarked estimators and the use of lures, camera traps alone are unlikely to produce abundance estimates with utility for brown treesnake management.

The value of quantitative environmental DNA analyses for the management of invasive and endangered native fish

Abstract Environmental DNA (eDNA) monitoring is a useful tool for species detection but its use in addressing management questions remains scarce. One factor limiting the use of eDNA as a routine monitoring tool is uncertainty around the potential of eDNA data to estimate species abundance. While several confounding factors limit the ability of eDNA data to estimate absolute abundances at large spatial and temporal scales, eDNA data have the potential to estimate relative species abundances patterns at smaller scales, and this information can assist management. Environmental DNA and conventional monitoring surveys were conducted in the Abercrombie River catchment (Australia) where an incursion of the invasive redfin perch (Perca fluviatulis) threatens the survival of a population of endangered Macquarie perch (Macquaria australasica). Species‐specific assays were used to quantify eDNA concentrations from water samples and estimate the relative abundance of both species. Electrofishing and fyke netting surveys were used to validate key observations from the eDNA survey. Environmental DNA of both species was detected at all sites except one, where redfin perch DNA was not detected. Between species comparisons of eDNA concentrations revealed a clear negative relationship between the eDNA concentrations of both species, consistent with other evidence of redfin perch having a negative impact on Macquarie perch populations. Between site comparisons of redfin perch eDNA concentrations showed evidence of a novel incursion of the species in the upper reaches of the Abercrombie River and conventional monitoring in the following year confirmed the pattern of increased redfin perch abundances from downstream to upstream sites. Relative comparisons of eDNA concentrations of aquatic species can be used to assess species interactions and reveal unexpected species abundance patterns (e.g. allowing inferences of novel incursions of invasive species). This information is critical to evaluate current, and design future, management strategies. Consequently, while deriving absolute species abundances from quantitative eDNA data may remain challenging, the use of quantitative eDNA surveys can provide relative abundance patterns valuable to the conservation and management of invasive and endangered species. The quantitative nature of eDNA survey data has been debated extensively in the current literature because of potential confounding influences. Current study results show that these confounding influences may be less problematic at small spatial scales and quantitative eDNA data can be effective to monitor relative species abundances patterns.

Splitting The Scatter: Distinguishing Marine Organisms From Oceanographic Structures Using Acoustic Monitoring

In the northwest Pacific Ocean, off the Sanriku coast of Japan, convergence between the Tsugaru Warm Current (TWC) and the cold Oyashio Current (OC) results in the formation of highly dynamic oceanographic features that promote high biodiversity and generate hotspots for a range of commercially important fisheries. However, their effects on local biodiversity over much smaller spatiotemporal scales ( < 1 km) remains unclear. With the development of acoustic technology in recent years, echo-sounders are increasingly being used to conduct high-precision fishery resource assessments and detect small-scale variability in the oceanic thermohaline structure. In this study, we conducted a simultaneous hydrographic and dual-frequency echo-sounder survey to discriminate oceanographic features and marine organisms in the TWC-OC confluence zone. Echograms of acoustic backscatter measured at 38 kHz detected similar oceanographic features that were obtained from our hydrographic survey observations, but these features were less pronounced in the 120 kHz echograms. The dynamic oceanographic structure in the TWC-OC zone returned a large amount of backscatter, making it difficult to identify marine organisms from the scatter. The frequency differences of volume backscattering strength (SV) were, however, able to distinguish oceanographic structures from zooplankton detections. Outcomes from this study highlight the difficulty of distinguishing between hydrographic and biological detections in dynamic oceanographic environments. Further research into the acoustic frequency characteristics of heterogeneous hydrographic features will help better understand how species distributions are affected, so that the acoustic method can be used to provide more accurate estimates of species abundance.

Climate Change May Cause Shifts in Growth and Instantaneous Natural Mortality of American Shad Throughout Their Native Range

AbstractAmerican Shad Alosa sapidissima is an anadromous species with populations ranging along the U.S. Atlantic coast. Past American Shad stock assessments have been data limited and estimating system‐specific growth parameters or instantaneous natural mortality (M) was not possible. This precluded system‐specific stock assessment and management due to reliance on these parameters for estimating other population dynamics (such as yield per recruit). Furthermore, climate‐informed biological reference points remain a largely unaddressed need in American Shad stock assessment. Population abundance estimates of American Shad and other species often rely heavily on M derived from von Bertalanffy growth function (VBGF) parameters. Therefore, we developed Bayesian hierarchical models to estimate coastwide, regional, and system‐specific VBGF parameters and M using data collected from 1982 to 2017. We tested predictive performance of models that included effects of various climate variables on VBGF parameters within these models. System‐specific models were better supported than regional or coast‐wide models. Mean asymptotic length (L∞) decreased with increasing mean annual sea surface temperature (SST) and degree days (DD) experienced by fish during their lifetime. Although uncertain, K (Brody growth coefficient) decreased over the same range of lifetime SST and DD. Assuming no adaptation, we projected changes in VBGF parameters and M through 2099 using modeled SST from two climate projection scenarios (Representative Concentration Pathways 4.5 and 8.5). We predicted reduced growth under both scenarios, and M was projected to increase by about 0.10. It is unclear how reduced growth and increased mortality may influence population productivity or life history adaptation in the future, but our results may inform stock assessment models to assess those trade‐offs.

Species richness is positively related to mental health – A study for Germany

Nature benefits human health. To date, however, little is known whether biodiversity relates to human health. While some local and city level studies show that species diversity, as a measure of biodiversity, can have positive effects, there is a lack of studies about the relationship between different species diversity measures and human health, especially at larger spatial scales. Here, we conduct cross-sectional analyses of the association between species diversity and human health across Germany, while controlling for socio-economic factors and other nature characteristics. As indicators for human health, we use the mental (MCS) and physical health (PCS) component scales of the German Socio-Economic Panel (SOEP, Short Form Health Questionnaire – SF12). For species diversity, we use species richness and abundance estimates of two species groups: plants and birds. We phrase the following hypotheses: plant and bird species are positively associated with mental and physical health (H1 & H3); bird abundance is positively related to mental health (H2). Our results demonstrate a significant positive relationship between plant and bird species richness and mental health across all model variations controlling for a multitude of other factors. These results highlight the importance for species diversity for people’s mental health and well-being. Therefore, policy makers, landscape planners and greenspace managers on the local and national level should consider supporting biodiverse environments to promote mental health and wellbeing. For this purpose, we propose to use species diversity measures as indicators for salutogenic (health promoting) characteristics of nature, landscape and urban green space.

Using Aerial Photogrammetry to Assess Stock-Wide Marine Turtle Nesting Distribution, Abundance and Cumulative Exposure to Industrial Activity

The lack of accurate distribution maps and reliable abundance estimates for marine species can limit the ability of managers to design scale-appropriate management measures for a stock or population. Here, we tested the utility of aerial photogrammetry for conducting large-scale surveys of nesting marine turtles at remote locations, with a focus on the flatback turtle (Natator depressus) in the Pilbara region of Western Australia. Aerial surveys were conducted between 29 November and 6 December 2016 to overlap with the peak nesting season for flatback turtles and collected imagery was used to examine marine turtle distribution, abundance, and cumulative exposure to industrial activity relative to overlap with protected areas. Two observers independently reviewed aerial georeferenced photographs of 644 beaches and recorded turtle tracks and other evidence of turtle nesting activity. A total of 375 beaches showed signs of nesting activity by either flatback, green (Chelonia mydas) or hawksbill (Eretmochelys imbricata) turtles. Most of these beaches (85.3%) were located on islands, and the rest (14.7%) on the mainland. Half (n = 174) of the active beaches showed evidence of fresh (0–36 h. old) flatback nesting activity, with track abundance varying from 1.0 to 222.0 tracks·night−1. Six rookeries accounted for 62% of the Pilbara flatback stock. Remarkably, 77% of identified flatback rookeries occurred within protected areas. However, one-third (34%) of those were also located within 5 km of a major industrial site, including eight of the highest abundance beaches (50–250 tracks·night−1). Several key rookeries were also identified as being relatively unexposed to industry-related pressures but currently unprotected, highlighting the need for a cumulative impact assessment to be completed for this flatback stock. Finally, our aerial tallies and multiple ground-survey flatback track tallies were highly correlated and together with low intra- and inter-observer errors suggested that reliable data can be collected via aerial photogrammetry for nesting marine turtles. Such large-scale digitized surveys can therefore be used to assess the cumulative exposure of marine turtles to pressures, and to reveal new conservation opportunities.

Integrating automated acoustic vocalization data and point count surveys for estimation of bird abundance

Abstract Monitoring wildlife abundance across space and time is an essential task to study their population dynamics and inform effective management. Acoustic recording units are a promising technology for efficiently monitoring bird populations and communities. While current acoustic data models provide information on the presence/absence of individual species, new approaches are needed to monitor population abundance, ideally across large spatio‐temporal regions. We present an integrated modelling framework that combines high‐quality but temporally sparse bird point count survey data with acoustic recordings. Our models account for imperfect detection in both data types and false positive errors in the acoustic data. Using simulations, we compare the accuracy and precision of abundance estimates using differing amounts of acoustic vocalizations obtained from a clustering algorithm, point count data, and a subset of manually validated acoustic vocalizations. We also use our modelling framework in a case study to estimate abundance of the Eastern Wood‐Pewee (Contopus virens) in Vermont, USA. The simulation study reveals that combining acoustic and point count data via an integrated model improves accuracy and precision of abundance estimates compared with models informed by either acoustic or point count data alone. Improved estimates are obtained across a wide range of scenarios, with the largest gains occurring when detection probability for the point count data is low. Combining acoustic data with only a small number of point count surveys yields estimates of abundance without the need for validating any of the identified vocalizations from the acoustic data. Within our case study, the integrated models provided moderate support for a decline of the Eastern Wood‐Pewee in this region. Our integrated modelling approach combines dense acoustic data with few point count surveys to deliver reliable estimates of species abundance without the need for manual identification of acoustic vocalizations or a prohibitively expensive large number of repeated point count surveys. Our proposed approach offers an efficient monitoring alternative for large spatio‐temporal regions when point count data are difficult to obtain or when monitoring is focused on rare species with low detection probability.

Amphibians and reptiles from the Parque Nacional da Tijuca, Brazil, one of the world’s largest urban forests

Abstract: The Parque Nacional da Tijuca in Rio de Janeiro, Brazil, is considered to be one of the world’s largest urban forests, however no systematic inventory of its herpetofauna is available. In the present study, we surveyed the amphibians and reptiles of this park to assess its species composition (including secondary data) and obtain estimates of species richness and abundance. We conducted active searches (460 hours) between January 2013 and December 2015. We identified the taxa endemic to either the Atlantic Forest or Rio de Janeiro state, and verified the conservation status of each species in the international, Brazilian, and state red lists. We also estimated the species richness and sampling sufficiency by rarefaction curves and Bootstrap richness estimator, and analyzed the distribution of the species abundance in Whittaker plots. We recorded 3,288 individuals over 36 months, representing 24 species of amphibians and 25 reptiles. The cumulative species curves, rarefaction, and the richness estimated indicated that sampling effort was adequate. Species abundance adjusted to the log-series model in both amphibians and reptiles. The four most abundant amphibians represented 70% of the individuals recorded in this group, while the two most abundant reptiles represented 60% of the total individuals. The inclusion of the secondary data raised the number of amphibian species to 38, and the number of reptiles to 36. Approximately 80% of the amphibian species and 28% of the reptile species recorded are endemic to the Atlantic Forest, and six of the amphibian species are endemic to Rio de Janeiro state. Six amphibian species and one reptile species are classified under some threat of extinction, and two reptile species were exotic. The considerable diversity of the herpetofauna of the Parque Nacional da Tijuca, which includes endemic and threatened species, reflects the effectiveness of the reforestation of this protected area and emphasizes the importance of its conservation.