Population Trends Of Species Research Articles

Population trends of Goričko agricultural landscape birds

Abstract Due to numerous bird surveys in the past 20 years, the avifauna of Goričko is relatively well known. For some species, the very first national ecological researches were conducted in this area. The article summarizes all bird surveys so far. It presents population trends of farmland species which is one of the most threatened bird groups in Europe. Most of the qualifying species of this habitat that are protected within the Natura 2000 network have suffered a decline at Goričko, specifically Quail Coturnix coturnix, Scops Owl Otus scops, Hoopoe Upupa epops, Woodlark Lullula arborea and White Stork Ciconia ciconia. The number of breeding pairs of the latter has not changed, but its fecundity has decreased. Furthermore, populations of other farmland bird species have decreased, for example Skylark Alauda arvensis, Stonechat Saxicola rubicola, Serin Serinus serinus and Common Linnet Linaria cannabina, as well as butterfly populations and tracts of grassland habitat types. National agricultural and nature conservation policies are evidently inefficient in protecting the biodiversity of Goričko. The most probable cause for bird population decline is agricultural intensification, which manifests itself at Goričko as disappearance and intensification of meadows, land consolidation, degradation of traditional orchards and use of pesticides. As a result of land consolidation hedges, uncultivated strips between fields, individual trees and bushes and minority habitat types are disappearing, whereas the surface of arable fields is increasing. Nature conservation measures performed by the Public Institute Goričko Nature Park with the support of DOPPS – BirdLife Slovenia volunteers seem to be efficient, but are spatially and temporally constrained. For this reason, they cannot serve as a substitute for insufficient systemic financing which could be improved by substantive and financial reform of the agri-environmental scheme. Currently, a negligible percentage (1% in 2016) of Goričko is covered by agrienvironmental scheme measures with positive influence on qualifying species and habitat types. As a consequence, only an insignificant share of subsidies from the Rural Development Plan is used for nature protection at Goričko. If the system of agricultural subsidies remains unaltered, no improvement of the conditions for bird conservation at Goričko can be expected.

Лісонасінна база в Україні: сучасний стан та шляхи розвитку

Здійснено аналіз сучасного стану лісового селекційного насінництва в Україні. Встановлено, що база для ведення насінництва лісових порід, яка успішно формувалася впродовж 1960-х − початку 1990-х років, не набула подальшого розвитку та на сьогодні гостро потребує осучаснення. Відповідні заходи необхідно здійснити у формі виділення та створення нових об’єктів, інвентаризації та генетичної паспортизації наявних об’єктів, а також вдосконалення теоретичних засад лісового насінництва, зокрема, в частині розроблення та запровадження уніфікованого лісонасінного районування і забезпечення комплексного характеру лісового насінництва на основі ширшого використання популяційних методів селекції.
 Обґрунтовано необхідність розроблення Перспективної програми розвитку лісового насінництва, збереження та відтворення генетичних ресурсів лісових порід, а також осучаснення законодавчої та нормативної бази лісового насінництва, зокрема, чинних «Настанов з лісового насінництва», для запровадження норм та положень, які забезпечували б ефективне збереження та відтворення лісових генетичних ресурсів в умовах глобальних кліматичних змін, інтенсивного антропогенного навантаження та лісокористування, а також несприятливих біотичних процесів, прояв яких спостерігається на території України.
 У межах зазначеної програми потрібно передбачити розширення мережі дослідних об’єктів “in sity” та “ex sity”, що мають за мету вивчення міжпопуляційної мінливості лісових порід на основі створення системної мережі географічних культур, збереження найцінніших генотипів та популяцій, оцінювання комбінаційної здатності плюсових дерев, з наступним створенням на цій основі лісонасінних плантацій другого порядку; адаптацію діючих актів у сфері лісового насінництва до норм Європейського Союзу.

Developing biodiversity indicators for African birds

AbstractBiodiversity indicators are essential for monitoring the impacts of pressures on the state of nature, determining the effectiveness of policy responses, and tracking progress towards biodiversity targets and sustainable development goals. Indicators based on trends in the abundance of birds are widely used for these purposes in Europe and have been identified as priorities for development elsewhere. To facilitate this we established bird population monitoring schemes in three African countries, based on citizen science approaches used in Europe, aiming to monitor population trends in common and widespread species. We recorded > 500 bird species from c. 450 2-km transects in Botswana, > 750 species from c. 120 transects in Uganda, and > 630 species from c. 90 transects in Kenya. Provisional Wild Bird Indices indicate a strong increase in bird populations in Botswana and a small decrease in Uganda. We also provide comparisons between trends of habitat generalists and specialists, of birds within and outside protected areas, and between Afro-Palearctic migrants and resident birds. Challenges encountered included recruiting, training and retaining volunteer surveyors, and securing long-term funding. However, we show that with technical support and modest investment (c. USD 30,000 per scheme per year), meaningful biodiversity indicators can be generated and used in African countries. Sustained resourcing for the existing schemes, and replication elsewhere, would be a cost-effective way to improve our understanding of biodiversity trends globally, and measure progress towards environmental goals.

Escape from predators and genetic variance in birds.

Predation is a common cause of death in numerous organisms, and a host of antipredator defences have evolved. Such defences often have a genetic background as shown by significant heritability and microevolutionary responses towards weaker defences in the absence of predators. Flight initiation distance (FID) is the distance at which an individual animal takes flight when approached by a human, and hence, it reflects the life-history compromise between risk of predation and the benefits of foraging. Here, we analysed FID in 128 species of birds in relation to three measures of genetic variation, band sharing coefficient for minisatellites, observed heterozygosity and inbreeding coefficient for microsatellites in order to test whether FID was positively correlated with genetic variation. We found consistently shorter FID for a given body size in the presence of high band sharing coefficients, low heterozygosity and high inbreeding coefficients in phylogenetic analyses after controlling statistically for potentially confounding variables. These findings imply that antipredator behaviour is related to genetic variance. We predict that many threatened species with low genetic variability will show reduced antipredator behaviour and that subsequent predator-induced reductions in abundance may contribute to unfavourable population trends for such species.

Using citizen science butterfly counts to predict species population trends

Citizen scientists are increasingly engaged in gathering biodiversity information, but trade-offs are often required between public engagement goals and reliable data collection. We compared population estimates for 18 widespread butterfly species derived from the first 4 years (2011-2014) of a short-duration citizen science project (Big Butterfly Count [BBC]) with those from long-running, standardized monitoring data collected by experienced observers (U.K. Butterfly Monitoring Scheme [UKBMS]). BBC data are gathered during an annual 3-week period, whereas UKBMS sampling takes place over 6 months each year. An initial comparison with UKBMS data restricted to the 3-week BBC period revealed that species population changes were significantly correlated between the 2 sources. The short-duration sampling season rendered BBC counts susceptible to bias caused by interannual phenological variation in the timing of species' flight periods. The BBC counts were positively related to butterfly phenology and sampling effort. Annual estimates of species abundance and population trends predicted from models including BBC data and weather covariates as a proxy for phenology correlated significantly with those derived from UKBMS data. Overall, citizen science data obtained using a simple sampling protocol produced comparable estimates of butterfly species abundance to data collected through standardized monitoring methods. Although caution is urged in extrapolating from this U.K. study of a small number of common, conspicuous insects, we found that mass-participation citizen science can simultaneously contribute to public engagement and biodiversity monitoring. Mass-participation citizen science is not an adequate replacement for standardized biodiversity monitoring but may extend and complement it (e.g., through sampling different land-use types), as well as serving to reconnect an increasingly urban human population with nature.

Suitability of Two Sampling Methods for Determining the Population Trends of Certain Sap-Sucking Species Inhabiting Tomato and Cucumber Plantations

Faunistic composition and seasonal abundance of certain sap-sucking species inhabiting tomato and cucumber plantations were determined by using sweep net and direct count methods, during summer seasons of 2015 and 2016 in Assiut Governorate, Northern Upper Egypt. Twelve species belonging to 8 families and 3 orders in addition to the acarid mite were recorded. Heteropteran species were found to be constituted 69.24% of the gathered species. However, Homopteran species were found to be constituted 15.38%. Thysanoptera and Tetranichidae were presented by 7.69% for each. Concerning to the sampling method, 76.92% of the collected species were captured by the sweep net method, while 23.08% were gathered by the direct count method. The recovered species were classified as predominantly predaceous, predominantly phytophagous, predaceous in part and phytophagous in part species. Seasonal abundance of the recorded species was determined. The distinct predators, Coranus aegyptius (Fabricius, 1775) and Orius spp. showed relatively low abundance percentages. The predatory-phytophagous mirid species [Campylomma unicolor Poppius, 1914; Nesidiocoris tenuis (Reuter, 1895); Creontiades pallidus (Rambur, 1839). and Deraeocoris serenus (Douglas & Scott, 1868)], showed different abundance percentages. Amongst these taxa, N. tenuis revealed the highest abundance percentage on tomato plantations with an average of 63.00 and 75.00% during 2015 and 2016 seasons, respectively. The distinct phytophagous species, Thrips tabaci Lindeman, 1889; Bemisia tabaci (Gennadius, 1889) and Tetranychus urticae Koch, 1836 presented the greatest abundance percentages on cucumber when estimated by the direct count method.So, this work can be reflect the importance of sweep net as a suitable sampling method for determine the faunistic composition of the flight predatory insects inhabiting tomato and cucumber. However, direct count can be consider the most suitable method for determine the population trends of mobile or non-mobile arthropods inhabiting the same crops. Also, use of more than one sampling method could be successful to clarify the relation between useful and harmful arthropod species.

Visual lures increase camera-trap detection of the southern cassowary (Casuarius casuarius johnsonii)

Context Monitoring is a key component in managing wildlife populations and is critical for revealing long-term population trends of endangered species. Cryptic or highly mobile species that occur in low densities and in remote terrain require the development of specific monitoring methods. The southern cassowary is an Australian endangered species that poses many challenges for conducting population surveys. Aims The aims of the present study were to determine the effectiveness of camera traps in detecting cassowaries at a site, to determine whether visual lures increased detection rates, and to explore the potential of camera traps in population surveys. Methods Coloured lures (mimicking large blue and red fruit) were placed in front of a set of camera traps and compared with controls (no lures) at 29 survey sites on the Daintree coast, northern Queensland, Australia. Key results Camera traps with lures (1) detected more birds, (2) had a shorter detection latency, (3) had a marginally greater number of captures, (4) experienced a longer capture duration, (5) were more likely to have the cassowary stop in front of the camera, and (6) achieved a 95% probability of detecting cassowaries in 12 trap days, compared with 28 trap days without lures. Conclusions An increase in the number of cassowaries detected, the reduction in camera latency times and the ability to identify the birds enables a more efficient approach to estimating population sizes over existing methods. This is the first published study to use visual lures to conduct camera trapping of birds. Implications The use of camera traps with lures is a practical and cost-efficient technique for the rapid detection of cassowaries at a site and lends itself to studies of population structure, size and trends.

Population ecology of a cryptic arboreal snake (Hoplocephalus bitorquatus)

Biologists have traditionally been reluctant to study arboreal snakes due to low rates of capture. Overlooking such taxa can mislead interpretations of population trends for data-deficient species. We used regularly spaced transect searches and standard capture–mark–recapture techniques to describe population structure, growth rates, survival and capture probability in a population of the pale-headed snake (Hoplocephalus bitorquatus) in southern Queensland. We obtained data from 194 captures of 113 individual snakes between 2009 and 2015. Using the Cormack–Jolly–Seber method, we estimated apparent annual survival in subadult snakes at 0.23 ± 0.01 (s.e.) and 0.81 ± 0.08 for adults. Capture probability was estimated at 0.16 ± 0.14 per session in subadult snakes and 0.33 ± 0.06 for adults. Within the red gum forests of our study site, we estimate pale-headed snake density at ~13 ± 7 ha–1. Using von Bertalanffy growth modelling, we predict that snakes reach sexual maturity after about four years and may live for up to 20. Our results suggest that the species is a ‘k’ strategist, characterised by slow maturation and low fecundity. These traits suggest that populations will recover slowly following decline, exacerbating the risk of local extinction.

Decline of the Land SnailAnguispira alternata(Pulmonata: Discidae) in Pennsylvania, U.S.A

Population declines of species can be a concern, but before taking action, we need to verify whether apparent declines are real. Land snails are one of the most threatened groups of animals in the world, and anecdotes suggest that the abundance of the land snail Anguispira alternata has declined in Pennsylvania, U.S.A., over the past few decades. Might the apparent decline represent inadequate sampling by recent surveyors or could it represent a real decline? Past search effort is rarely documented, hindering direct comparisons of search effort. We used 547 museum records of A. alternata collected primarily from 1890 to 1960 and 2000 to 2015. Following two lines of reasoning, we conclude that the abundance of A. alternata has actually declined. (1) The smaller proportion of collecting events that found A. alternata after year 2000 suggests an actual decline of A. alternata in modern decades, regardless of the total number of collecting events. (2) The accumulation curve of new county records for all land snail species showed similar slopes in both past and modern decades, indicating comparable search effort in both time periods. The apparent decline of A. alternata was not explained by differential effort with respect to snail size or geographical area searched. The decline appears to have begun about 1960, although relatively little collecting effort from 1960 to 2000 decreases confidence in our ability to infer timing of abundance change in those decades. We speculate about three hypotheses regarding the decline (acid precipitation, climate warming, human mediated disturbance) and conclude that the historical increase in acid precipitation best matches the timing of the snail's decline. Population trends of other snail species and trends of A. alternata in other geographical areas should be studied to further explore these and other hypotheses. Our study highlights the importance of museum collections in understanding the current biodiversity crisis.

What drives current population trends in forest birds – forest quantity, quality or climate? A large-scale analysis from northern Europe

Changes in forestry practices and on-going climate change may both have large impacts on forest bird populations. However, large-scale analyses of the effects of temporal changes in forest structure on forest bird numbers are largely lacking. We compared temporal trends from two Swedish nationwide long-term monitoring schemes, the Swedish Bird Survey (1998–2015) and the Swedish National Forestry Inventory (1983–2014), giving representative values for both forest and bird changes over an area of 35millionha. Since 1998 the total area of middle-aged and mature forest increased by 6.4%. In parallel, several forest structures potentially beneficial to birds (dead wood, retention trees on clear cuts, multi-layer forests, old forest and broadleaved forest) increased somewhat in abundance, most likely as a result of legislation changes and increasing areas under forest certification schemes. Summer temperatures also increased, with warm summers dominating since 2002. In 1998–2015, the population sizes of 58 forest bird species on average increased, as did the number of species observed per route, with no general difference between forest specialists (16 species) and generalists (42 species). However, from around 2005, the positive trends in bird numbers and many forest structures have levelled out. An analysis of species population trends in relation to a measure of climate sensitivity (Species Temperature Index, STI) suggested that forest birds, just like Swedish birds in general, have indeed been affected by a warming climate. But given their STI, forest birds on average had more positive trends than non-forest birds, suggesting that other factors than climate have affected them positively. Strong candidate factors are the documented changes in forest quality and quantity. Whereas our data and analyses are correlational, and no firm conclusions on causality therefore can be drawn, it is reasonable to assume that the recent increases in forest quantity, forest quality, and summer temperatures, all have contributed to the general increase in forest bird numbers in Sweden. But the relative contribution of these driving forces remains to be determined. When it comes to the potentially positive effects of improving forest quality in terms of increases in old forest, stratification, retention trees and dead wood, it is noteworthy that many of the positive trends in forest structures since the mid-1990s seem to have ceased recently.

Differentiating the effects of climate and land use change on European biodiversity: A scenario analysis.

Current observed as well as projected changes in biodiversity are the result of multiple interacting factors, with land use and climate change often marked as most important drivers. We aimed to disentangle the separate impacts of these two for sets of vascular plant, bird, butterfly and dragonfly species listed as characteristic for European dry grasslands and wetlands, two habitats of high and threatened biodiversity. We combined articulations of the four frequently used SRES climate scenarios and associated land use change projections for 2030, and assessed their impact on population trends in species (i.e. whether they would probably be declining, stable or increasing). We used the BIOSCORE database tool, which allows assessment of the effects of a range of environmental pressures including climate change as well as land use change. We updated the species lists included in this tool for our two habitat types. We projected species change for two spatial scales: the EU27 covering most of Europe, and the more restricted biogeographic region of 'Continental Europe'. Other environmental pressures modelled for the four scenarios than land use and climate change generally did not explain a significant part of the variance in species richness change. Changes in characteristic bird and dragonfly species were least pronounced. Land use change was the most important driver for vascular plants in both habitats and spatial scales, leading to a decline in 50-100% of the species included, whereas climate change was more important for wetland dragonflies and birds (40-50%). Patterns of species decline were similar in continental Europe and the EU27 for wetlands but differed for dry grasslands, where a substantially lower proportion of butterflies and birds declined in continental Europe, and 50% of bird species increased, probably linked to a projected increase in semi-natural vegetation. In line with the literature using climate envelope models, we found little divergence among the four scenarios. Our findings suggest targeted policies depending on habitat and species group. These are, for dry grasslands, to reduce land use change or its effects and to enhance connectivity, and for wetlands to mitigate climate change effects.

Unrecognized diversity in New Guinean crayfish species (Decapoda, Parastacidae): The evidence from molecular data.

The phylogenetic relationships among imported ornamental crayfish belonging to the genus Cherax were inferred from a combined dataset of 3 mitochondrial genes (COI, 16S and 12S) and by comparison with available GenBank sequences of 14 Cherax species. Furthermore, the concordance of previously described species obtained from a wholesaler (Cherax boesemani, C. holthuisi and C. peknyi) with available GenBank sequences was verified based on COI with special respect to comparison with sequences assigned as Cherax species. Recently described species C. gherardiae, C. pulcher and C. subterigneus belong to the northern group of Cherax species. Comparison and analysis with other GenBank COI sequences show previously unreported diversity of New Guinean species, suggesting 5 putative new species. Surprisingly, species assigned to the subgenus Astaconephrops do not form a monophyletic clade; this subgenus should be reappraised relative to the purported typical morphological characteristic of the uncalcified patch on male chelae. Increasing importation of crayfish underscores the importance of accurate species identification. Use of basic molecular methods is a necessary requisite for documenting occurrence, abundance and population trends of target species. Consequently, it helps to support eventual conservation decision-making by stakeholders.

Effects of harbour and ship channel construction on breeding seabirds

Bird population changes were studied during the construction of the new Vuosaari Harbour in 2001–2011 (Helsinki, Finland, N60°14.52' E25°9.07'). Part of the monitoring programme was to determine the possible impacts of harbour and ship channel construction on breeding seabird populations. The study revealed that the population trends of most species showed no substantial difference between islets close to harbour and channel and more distant reference islet. A Black-headed Gull colony was destroyed by landfill but that was deliberately and with permission. The trends of Ruddy Turnstone and Great Black-backed Gull populations were more negative in near than in distant islets. In the surrounding archipelago, the Barnacle Goose, Mew Gull and Common Black-headed Gull clearly increased during the study years. The European Herring Gull decreased distinctly, which was probably caused by the removal of individuals from the rubbish dumps around Helsinki. There were some differences between the restricted-and open-access islands. The population of Herring Gull was higher and the decline stronger in the restricted areas, while the Common Ringed Plover population simultaneously increased.

New opportunities for conservation of handfishes (Family Brachionichthyidae) and other inconspicuous and threatened marine species through citizen science

Volunteer divers participating in the Reef Life Survey (RLS) program actively assist species conservation efforts by generating data for threat assessments and population trend monitoring, through in-water restoration efforts, and through outreach of marine conservation messages. Up to 2014, standardised underwater visual survey data provided by RLS divers described densities of 495 cryptic fish species at over 1200 sites distributed around Australia. Each species was recorded on 34 separate transect blocks on average, allowing the first assessments of population trends for many species. These data highlight the threatened and data deficient status of endemic Australian handfish species. At least five shallow-water handfish species are potentially threatened, including the smooth handfish Sympterichthys unipennis, which has not been sighted for over 200years, but is yet to be included on any threatened species list. RLS divers undertook directed searches at key historical locations for two handfish species, the red handfish Thymichthys politus, now only known from a single reef, and Ziebell's handfish Brachiopsilus ziebelli, with no confirmed sighting for over a decade. From a total of 100h of underwater search effort, only four red handfish were recorded, all at a site threatened by adjacent human activity. These and other handfish species should be considered for inclusion on the IUCN Red List given that populations are either very small or have vanished, spawning substrates have probably declined, and the species lack a larval dispersal stage. More importantly, the absence of information on the conservation status of the majority of marine species needs urgent attention, including through expanded citizen science efforts, if management intervention is to occur and extinctions minimised.

Quantifying the long-term decline of the West European hedgehog in England by subsampling citizen-science datasets

It is increasingly important to be aware of trends in species abundances in order to be able to act ahead of possible irrecoverable declines and extinctions. Long-term monitoring of species is generally used to determine how a species is faring, which is essential knowledge for conservation planning and design. However, monitoring programmes that encompass large areas and long timespans are rare or non-existent for the vast majority of species. Citizen-science-based datasets provide a wealth of data on past and present species’ occurrences but are often biased to a large extent. We evaluate the potential use of such datasets by subsampling datasets collected over different time periods to detect trends in the long-term temporal abundance of West European hedgehogs (Erinaceus europaeus), a species which is thought to be in decline in parts of its geographic range. We used subsampling as a means to account for quantitative differences between two non-systematic datasets of West European hedgehog occurrences in England; one dataset was collected by the public between 1960 and 1975 and one was collected between 2000 and 2015. Here, we confirm and quantify previous anecdotal evidence of a long-term decline of the species throughout England. We find that although the West European hedgehog is still widespread in England, a 5.0 to 7.4 % decline in occupied grid cells was observed when comparing the 2000–2015 dataset to the previous survey in 1960–1975 after adjusting for differences in effort. This suggests that the decline of the relative abundance of West European hedgehogs is moderate in England, 25 % being an amber alert for birds of conservation concern in the UK. Importantly, we show that subsampling disparate citizen-science datasets is a useful tool for monitoring species population trends.

Improved analysis of lek count data using N‐mixture models

ABSTRACTThe greater sage‐grouse (Centrocercus urophasianus) is a species of conservation concern in western North America that is experiencing ongoing population declines due to habitat loss, energy development, disease, and other factors. It is therefore imperative to have robust estimates of population size and trends in this species across its range as part of monitoring, management, and conservation efforts. Greater sage‐grouse are typically monitored by conducting counts of males at breeding leks, but the relationship between this index and true population size is unknown. In an attempt to improve the analyses of this population index, we examined the potential of N‐mixture models to evaluate population size, detection probability, and trend in greater sage‐grouse using lek count data collected over space and time. We used simulations to test how well the models recovered abundance and growth rate parameters with increasingly sparse count data. We found that the models correctly recovered parameters for scenarios with both constant and variable detection probability, even with up to 90% of the data missing, where 95% of simulations contained the true population growth rate parameter value within the 95% credible interval. We then applied the model to 13 years of lek count data from Montana, USA, collected at 2 spatial scales. Statewide, we determined that the population was decreasing by 7% per year on average over this time period, and that mean annual detection probability ranged from 0.20 to 0.76. In contrast, regressions of naïve counts over time showed a 9% annual decrease in population size with a confidence interval spanning 0. High interannual variability in detection probability demonstrates that naïve counts do not accurately measure interannual variability in population size, and may lead to misleading trends in population size over time. Although N‐mixture models still have limitations, they are a promising approach for conducting robust analyses of population trends for species that aggregate at discrete breeding sites, even when datasets are sparse or uneven. © 2016 The Wildlife Society.

Wood-boring beetles (Coleoptera: Scolytidae, Platypodidae) captured in ethanol-baited traps in a natural forest in Japan

We mainly examined the community structure and seasonal population trends of scolytid and platypodid species captured via ethanol-baited traps in a natural cool-temperate forest in Japan. The scolytid species in the tribe Xyleborini represented more than 70 % of individuals captured in ethanol-baited traps, although the platypodid species could be abundant in this study area. These results indicate that the scolytid species in tribe Xyleborini might have higher sensitivity to ethanol-baited traps than others and the ethanol-baited trapping method could target the limited number of scolytid and platypodid species. Therefore, analysis based only on the ethanol-baited trapping method may lead to misunderstanding the community structure of scolytid and platypodid species. The analysis of the seasonal changes in number of scolytid and platypodid species, using a generalized linear model (GLM) showed that the ethanol-baited traps appeared to function more effectively in spring than in other seasons. Hence, the trapping season should be considered when analyzing the data obtained from ethanol-baited trapping census, especially with scolytid and platypodid species.

Monitoring cryptic amphibians and reptiles in a Florida state park.

We monitored cryptic herpetofauna at Savannas Preserve State Park, Florida, by combining artificial cover counts with a quantitative paradigm for constructing and calculating population indices. Weekly indices were calculated from two consecutive days of data collection each week for 7 months from mid-winter to mid-summer in three habitats. Seventeen species were observed at least once, and time trends using index values were followed for six species. Among these, abundance and seasonal pattern information were obtained for an exotic species (greenhouse frog) and a species identified by the Florida Committee on Rare and Endangered Plants and Animals as threatened (Florida scrub lizard). We identified winter as the optimal time in this area to monitor populations for conducting annual assessments. This combined observation and indexing approach could provide managers or researchers with an economical means to quantitatively index population trends for multiple cryptic herpetofauna species simultaneously. Using artificial cover to sample within a population indexing design can be generalized beyond monitoring herpetofauna. Other forms of artificial cover that can be used as observation stations include aquatic artificial substrates, artificial tree cavities, artificial reefs, and other artificial aquatic structures and artificial sea grass units, among many others, and a wide range of taxa are suitable for population monitoring using artificial cover as observation stations in the approach we present, including insects, soil invertebrates, micro and macro aquatic invertebrates, fish, crustaceans, and small mammals.

Evaluating the effectiveness of overstory cover as a surrogate for bird community diversity and population trends

Landscape features are often used as surrogates for biodiversity. While landscape features may perform well as surrogates for coarse metrics of biodiversity such as species richness, their value for monitoring population trends in individual species is virtually unexplored. We compared the performance of a proposed habitat surrogate for birds, percentage cover of vegetation overstory, for two distinct aspects of bird assemblages: community diversity (i.e. species richness) and population trends. We used four different long-term studies of open woodland habitats to test the consistency of the relationship between overstory percentage cover and bird species richness across a large spatial extent (>1000km) in Australia. We then identified twelve bird species with long-term time-series data to test the relationship between change in overstory cover and populations trends. We found percentage cover performed consistently as a surrogate for species richness in three of the four sites. However, there was no clear pattern in the performance of change in percentage cover as a surrogate for population trends. Four bird species exhibited a significant relationship with change in percentage overstory cover in one study, but this was not found across multiple studies. These results demonstrate a lack of consistency in the relationship between change in overstory cover and population trends among bird species, both within and between geographic regions. Our study demonstrates that biodiversity surrogates representing community-level metrics may be consistent across regions, but provide only limited information about individual species population trends. Understanding the limitations of the information provided by a biodiversity surrogate can inform the appropriate context for its application.

Habitat‐specific population trajectories in boreal waterbirds: alarming trends and bioindicators for wetlands

AbstractIdentification of conservation priorities is a fundamental issue for successful nature conservation. This can be done by looking at population trends of species in different habitats. Boreal zone is the key breeding area for many Eurasian waterbirds. Wetlands of the boreal zone can be roughly classified into two different groups: nutrient‐poor oligotrophic and nutrient‐rich eutrophic water ecosystems. Earlier work has shown that eutrophic lake‐specialist species have declined compared with generalists and species preferring oligotrophic lakes. However, it is not known if species that live in both habitats show habitat‐specific population trends. We used monitoring data of breeding waterbirds in Finland from 1986 to 2013 to evaluate habitat‐specific population trends in five generalist duck species, which mostly overwinter in the coastal waters of West Europe. Population trend of tufted duck was highly significantly more positive in oligotrophic wetlands compared with populations in eutrophic wetlands, and two other species had similar but weaker effects. In addition, we established bird population state indicators for oligotrophic and eutrophic water ecosystems in Finland. The indicators revealed that the populations in eutrophic wetlands have on average halved since early 1990s. The populations in oligotrophic wetlands have remained stable, except a moderate decline since the late 2000s. Our findings support the idea that the waterbird populations of the eutrophic wetlands are in serious trouble. This is likely due to over‐eutrophication of these ecosystems. Conservation and management actions should be urgently taken to halt the loss of biodiversity in these globally threatened freshwater ecosystems.