Rate Of Population Change Research Articles

Population trends for Scripps's murrelet following eradication of black rats

ABSTRACTNest monitoring at Anacapa Island, California, USA, in 2001–2010 documented considerable benefits for Scripps's murrelets (Synthliboramphus scrippsi) following the eradication of black rats (Rattus rattus) in 2002. In 2014, post‐eradication monitoring resumed at Anacapa to update the number of occupied nests in monitored plots, count murrelets in nocturnal at‐sea congregations near Anacapa using round‐island spotlight surveys, and compare post‐eradication rates of population change (λ) estimated from nest counts and spotlight surveys. Nest counts and spotlight counts demonstrated increases; the overall number of nests increased 4.45 times from 2001 (11 nests) to 2014 (60 nests) and mean round‐island counts in 2014 (869 ± 592 [SD]) were higher than in 2001–2003 (227 ± 151). Time series regression yielded annual increases that were marginally higher for nests (λ = 1.151) compared to round‐island counts (λ = 1.122). The slight difference may have resulted from inherent differences in the indices used to measure λ, spatial biases in nest plots, data gaps in the regressions, and small sample biases for round‐island counts. The post‐eradication λ for murrelets at Anacapa was slightly higher than the mean response reported for other Alcidae (λ = 1.113). This was the first use of spotlight surveys to estimate λ based on counts of seabirds congregating at‐sea near breeding areas. This study provided vital information needed to better assess the risks and benefits of future island restoration actions, justification for further murrelet conservation efforts, and confirmation of spotlight surveys as a population monitoring tool for Scripps's murrelets. © 2017 The Wildlife Society.

Effects of tire leachate on the invasive mosquito Aedes albopictus and the native congener Aedes triseriatus.

Discarded vehicle tire casings are an important artificial habitat for the developmental stages of numerous vector mosquitoes. Discarded vehicle tires degrade under ultraviolet light and leach numerous soluble metals (e.g., barium, cadmium, zinc) and organic substances (e.g., benzothiazole and its derivatives [BZTs], polyaromatic hydrocarbons [PAHs]) that could affect mosquito larvae that inhabit the tire casing. This study examined the relationship between soluble zinc, a common marker of tire leachate, on mosquito densities in tire habitats in the field, and tested the effects of tire leachate on the survival and development of newly hatched Aedes albopictus and Aedes triseriatus larvae in a controlled laboratory dose-response experiment. In the field, zinc concentrations were as high as 7.26 mg/L in a single tire and averaged as high as 2.39 (SE ± 1.17) mg/L among tires at a single site. Aedes albopictus (37/42 tires, 81.1%) and A. triseriatus (23/42, 54.8%) were the most widespread mosquito species, co-occurred in over half (22/42, 52.4%) of all tires, and A. triseriatus was only collected without A. albopictus in one tire. Aedes triseriatus was more strongly negatively associated with zinc concentration than A. albopictus, and another common mosquito, C. pipiens, which was found in 17 tires. In the laboratory experiment, A. albopictus per capita rate of population change (λ′) was over 1.0, indicating positive population growth, from 0–8.9 mg/L zinc concentration (0–10,000 mg/L tire leachate), but steeply declined to zero from 44.50–89.00 mg/L zinc (50,000–100,000 mg/L tire leachate). In contrast, A. triseriatus λ′ declined at the lower concentration of 0.05 mg/L zinc (100 mg/L tire leachate), and was zero at 0.45, 8.90, 44.50, and 89.00 mg/L zinc (500, 10,000, 50,000 and 100,000 mg/L tire leachate). These results indicate that tire leachate can have severe negative effects on populations of container-utilizing mosquitoes at concentrations commonly found in the field. Superior tolerance to tire leachate of A. albopictus compared to A. triseriatus, and possibly other native mosquito species, may have facilitated the replacement of these native species as A. albopictus has invaded North America and other regions around the world.

High abundance and expression of transposases in bacteria from the Baltic Sea

Transposases are mobile genetic elements suggested to have an important role in bacterial genome plasticity and host adaptation but their transcriptional activity in natural bacterial communities is largely unexplored. Here we analyzed metagenomes and -transcriptomes of size fractionated (0.1–0.8, 0.8–3.0 and 3.0–200 μm) bacterial communities from the brackish Baltic Sea, and adjacent marine waters. The Baltic Sea transposase levels, up to 1.7% of bacterial genes and 2% of bacterial transcripts, were considerably higher than in marine waters and similar to levels reported for extreme environments. Large variations in expression were found between transposase families and groups of bacteria, with a two-fold higher transcription in Cyanobacteria than in any other phylum. The community-level results were corroborated at the genus level by Synechococcus transposases reaching up to 5.2% of genes and 6.9% of transcripts, which is in contrast to marine Synechococcus that largely lack these genes. Levels peaked in Synechococcus from the largest size fraction, suggesting high frequencies of lateral gene transfer and high genome plasticity in colony-forming picocyanobacteria. Together, the results support an elevated rate of transposition-based genome change and adaptation in bacterial populations of the Baltic Sea, and possibly also of other highly dynamic estuarine waters.

The Critically Endangered western chimpanzee declines by 80.

African large mammals are under extreme pressure from unsustainable hunting and habitat loss. Certain traits make large mammals particularly vulnerable. These include late age at first reproduction, long inter-birth intervals, and low population density. Great apes are a prime example of such vulnerability, exhibiting all of these traits. Here we assess the rate of population change for the western chimpanzee, Pan troglodytes verus, over a 24-year period. As a proxy for change in abundance, we used transect nest count data from 20 different sites archived in the IUCN SSC A.P.E.S. database, representing 25,000 of the estimated remaining 35,000 western chimpanzees. For each of the 20 sites, datasets for 2 different years were available. We estimated site-specific and global population change using Generalized Linear Models. At 12 of these sites, we detected a significant negative trend. The estimated change in the subspecies abundance, as approximated by nest encounter rate, yielded a 6% annual decline and a total decline of 80.2% over the study period from 1990 to 2014. This also resulted in a reduced geographic range of 20% (657,600 vs. 524,100 km2 ). Poverty, civil conflict, disease pandemics, agriculture, extractive industries, infrastructure development, and lack of law enforcement, are some of the many reasons for the magnitude of threat. Our status update triggered the uplisting of the western chimpanzee to "Critically Endangered" on the IUCN Red List. In 2017, IUCN will start updating the 2003 Action Plan for western chimpanzees and will provide a consensus blueprint for what is needed to save this subspecies. We make a plea for greater commitment to conservation in West Africa across sectors. Needed especially is more robust engagement by national governments, integration of conservation priorities into the private sector and development planning across the region and sustained financial support from donors.

Genomics of Adaptation Depends on the Rate of Environmental Change in Experimental Yeast Populations.

The rate of directional environmental change may have profound consequences for evolutionary dynamics and outcomes. Yet, most evolution experiments impose a sudden large change in the environment, after which the environment is kept constant. We previously cultured replicate Saccharomyces cerevisiae populations for 500 generations in the presence of either gradually increasing or constant high concentrations of the heavy metals cadmium, nickel, and zinc. Here, we investigate how each of these treatments affected genomic evolution. Whole-genome sequencing of evolved clones revealed that adaptation occurred via a combination of SNPs, small indels, and whole-genome duplications and other large-scale structural changes. In contrast to some theoretical predictions, gradual and abrupt environmental change caused similar numbers of genomic changes. For cadmium, which is toxic already at comparatively low concentrations, mutations in the same genes were used for adaptation to both gradual and abrupt increase in concentration. Conversely, for nickel and zinc, which are toxic at high concentrations only, mutations in different genes were used for adaptation depending on the rate of change. Moreover, evolution was more repeatable following a sudden change in the environment, particularly for nickel and zinc. Our results show that the rate of environmental change and the nature of the selection pressure are important drivers of evolutionary dynamics and outcomes, which has implications for a better understanding of societal problems such as climate change and pollution.

The study to estimate the floating population in Seoul, Korea.

Traffic-related pollutants have been reported to increase the morbidity of respiratory diseases. In order to apply management policies related to motor vehicles, studies of the floating population living in cities are important. The rate of metro rail transit system use by passengers residing in Seoul is about 54% of total public transportation use. Through the rate of metro use, the people-flow ratios in each administrative area were calculated. By applying a people-flow ratio based on the official census count, the floating population in 25 regions was calculated. The reduced level of deaths among the floating population in 14 regions having the roadside monitoring station was calculated as assuming a 20% reduction of mobile emission based on the policy. The hourly floating population size was calculated by applying the hourly population ratio to the regional population size as specified in the official census count. The number of people moving from 5 a.m. to next day 1 a.m. could not be precisely calculated when the population size was applied, but no issue was observed that would trigger a sizable shift in the rate of population change. The three patterns of increase, decrease, and no change of population in work hours were analyzed. When the concentration of particulate matter less than 10 μm in aerodynamic diameter was reduced by 20%, the number of excess deaths varied according to the difference of the floating population. The effective establishment of directions to manage the pollutants in cities should be carried out by considering the floating population. Although the number of people using the metro system is only an estimate, this disadvantage was supplemented by calculating inflow and outflow ratio of metro users per time in the total floating population in each region. Especially, 54% of metro usage in public transport causes high reliability in application.

Long‐term demography of the Northern Goshawk in a variable environment

Long‐term demography of the Northern Goshawk in a variable environment

Pandora’s box down-under: origins and numbers of mustelids transported to New Zealand for biological control of rabbits

This paper describes one of the world’s first large-scale experiments in biological control of a major vertebrate pest of agriculture, which was tried in New Zealand during the second half of the nineteenth century. Starting from the late 1860s, pasture damage in Southland and Otago by European rabbits was causing serious reductions in productivity of sheep (wool clip and lambing percentages) associated with malnutrition of the breeding ewes, and a consequent decline in the value of pastoral land. In response, and despite repeated local and international warnings, ferrets, stoats and weasels (Mustela furo, M. erminea and M. nivalis) were liberated on the worst of the rabbit-infested pastures. They were perceived as the ‘natural enemies of the rabbit’ but (unlike foxes) too small to threaten lambs. Over the 50 years after 1870, upwards of 75,000 ferrets, most imported from Australia or locally bred, were released in the South Island. Over the decade 1883–1892, at least 7838 stoats and weasels arrived from Britain. At least 25 shipments are known, with an average of only 10% mortality per shipment. Of the 3585 animals listed by species, 73% were weasels. The total cost of the ferret programme cannot now be estimated; that of stoats and weasels alone was at least £5441, probably twice that, or >$NZ 1–2 million in today’s money. Mustelids (and cats) killed many young rabbits, which was helpful because rates of change in rabbit populations are sensitive to variations in juvenile mortality, but in the most rabbit-prone semi-arid lands, mustelids could not remove enough rabbits to prevent the continuing damage to sheep pastures. The era of deliberate introductions of mustelids to control rabbits in New Zealand was short, expensive, and unsuccessful.

Combined analysis of roadside and off-road breeding bird survey data to assess population change in Alaska

ABSTRACT Management interest in North American birds has increasingly focused on species that breed in Alaska, USA, and Canada, where habitats are changing rapidly in response to climatic and anthropogenic factors. We used a series of hierarchical models to estimate rates of population change in 2 forested Bird Conservation Regions (BCRs) in Alaska based on data from the roadside North American Breeding Bird Survey (BBS) and the Alaska Landbird Monitoring Survey, which samples off-road areas on public resource lands. We estimated long-term (1993–2015) population trends for 84 bird species from the BBS and short-term (2003–2015) trends for 31 species from both surveys. Among the 84 species with long-term estimates, 11 had positive trends and 17 had negative trends in 1 or both BCRs; negative trends were primarily found among aerial insectivores and wetland-associated species, confirming range-wide negative continental trends for many of these birds. Three species with negative trends in the contiguous Unit...

Some Aspects of the Dynamics of a Hunted Bobwhite Population

Dynamics of a hunted bobwhite population have been investigated on a 1,450-acre study area near Carbondale, Illinois since 1952. Habitat conditions have not changed greatly during the study, and November densities have oscillated regularly about a rather stable long-term mean. Most of the variance of annual rates of population change is due to variation in net productivity from spring to fall rather than to variation in net losses from fall to spring. Population declines from November to April averaged 66% (range 36 to 81%); about 0.66 of this resulted from hunting. Post-hunting mortality, which was slightly density-related, partially compensated for hunting losses. Spring densities were correlated with (r = +o.75) and almost as variable as preceding fall populations. Net increases from spring to fall varied from 17 to 383 and averaged 235% of the breeding population. Multiple regression analysis showed that annual rates of productivity were significantly influenced by the combined effect of breeding density, length of snow cover during the previous 2 winters, and amounts of prenesting rainfall. Annual rates of population change were inversely related to the preceding fall density, but strong correlations between successive seasonal population levels caused periods of change as well as highs and lows to persist for several years. Major highs and lows each occurred at 8- to 10-year intervals. It was not clear whether 2 severe winters caused the apparent cyclic regularity or merely accentuated the lows.

A Mid-Atlantic and a National Population Model of Northern Bobwhite Demographic Sensitivity

Numerous field studies have estimated fecundity and survival rates for northern bobwhites (Colinus virginianus), but a synthetic population model based on life-stage simulation analysis (LSA) was only recently developed to examine demographic sensitivity of the finite rate of population change. We compare local demographic parameters of bobwhite versus a national compilation to identify limiting demographic factors for improved regional habitat planning and management. The national compilation provided a useful overview but combined parameters across populations at different latitudes and under different management regimes. We parameterized our LSA model to examine the sensitivity of the finite rate of growth (k) to simulated variation in 9 demographic parameters primarily estimated from field studies for one population in regional decline in New Jersey. Our model results predicted population declines in New Jersey (k 1⁄4 0.55) comparable to the national estimate (k 1⁄4 0.54), but notable differences occurred in sensitivity of demographic variables. The national model predicted winter survival of adults made the greatest contribution to variance of k (r2 1⁄4 0.42) followed by summer survival of adults (r2 1⁄4 0.13), and survival of chicks (r2 1⁄4 0.11). Our regional model for New Jersey also predicted winter and summer survival of adults would make the greatest contribution to variance of k (r2 1⁄4 0.33 and r2 1⁄4 0.13). The New Jersey model, in contrast to the national model, showed that annual variation in components of fecundity had a large effect on Var(k): including clutch size (r2 1⁄4 0.18 vs. national r2 1⁄4 0.01), nest success (r2 1⁄4 0.20 vs. national r2 1⁄4 0.06), and the number of young produced per nest that survived 30 days (r2 1⁄4 0.53 vs. national r2 1⁄4 0.16). Slopes of linear regression between simulated variation in each demographic variable against k were similar between the national and regional models. The slope for number of young produced per nest that survived 30 days with one exception was lower in the New Jersey data indicating more young are required to realize a stationary population. Our simulation results suggest management practices that improve winter survival or the number of young surviving 30 days will have the greatest potential to increase bobwhite population growth rate in New Jersey. Future linkage of models of demographic performance to experimental habitat manipulations will aid regional scientific planning to improve necessary habitat management.

Biome‐scale signatures of land‐use change on raptor abundance: insights from single‐visit detection‐based models

Summary Declines in raptor populations often result from the transformation of natural habitats to anthropogenic land uses, but the rate of population change can vary greatly among species. Declines associated with land transformation have been linked to loss of foraging habitat, prey resources and nest sites due to expanding cultivation, overgrazing and disturbance of nests and persecution by humans. We combined extensive road‐survey counts of raptors, large‐scale GIS data sets and a single‐visit conditional likelihood N‐mixture model to generate biome‐scale projections of abundance as a function of environmental covariates while correcting for detection error and other forms of zero inflation. This approach was employed to investigate how land‐use transformations in the threatened Cerrado savannas and Pantanal wetlands in Brazil have affected the populations of raptors on a large scale (>300 000 km2). We predicted that predominance of land uses with fewer or less accessible prey and scarcer nesting sites would sustain smaller raptor populations. Twelve species were encountered sufficiently to estimate abundance, while 20 others were encountered too infrequently to permit abundance estimation. Detection of all 12 species was influenced by time of day, with variable species‐specific effects that followed expectations based on foraging and flight behaviour. Abundance of most species was negatively influenced by conversion of natural habitats to pastures, an effect that held even for generalist species considered poor indicators of habitat quality, but was not universally impacted by urbanization and soya beans, sugarcane and Eucalyptus plantations, confirming the expectation that some species may tolerate these habitats. Spatial projections of abundance appeared realistic for most species. Synthesis and applications. Protection of the remaining natural habitats is essential to prevent further decline of raptor populations in the Brazilian Cerrado and Pantanal, and restoration of unproductive pastures into natural habitat could prove an efficient strategy to recover diminished raptor populations. The conditional likelihood single‐visit approach is a valid and useful tool for measuring population size and for making detection‐corrected inferences of abundance over large geographical scales with sensible research budgets. Incorporating the approach into a multispecies framework would allow future studies to make important inferences for entire communities.

Predicting the Stability of Endangered Stonecats in the LaPlatte River, Vermont

AbstractStonecats Noturus flavus in Vermont conform to a rare distribution pattern (as designated by Rabinowitz 1981) because their known distribution within the state is limited to the LaPlatte and Missisquoi rivers. We focused on Stonecats in the LaPlatte River to predict the stability of the population. During 2012–2014, we captured Stonecats via backpack electrofishing; fish were PIT‐tagged (>90 mm TL) and marked with visible implant elastomer. Among the 1,671 Stonecats that were captured, 1,252 were PIT‐tagged. Only 156 (12%) of the PIT‐tagged fish were recaptured, and only 22 of those individuals were recaptured more than once. The Pradel model in Program MARK was used to estimate apparent survival (Φ) and seniority, which were used to derive the rate of population change (λ) for the Stonecat encounter histories we studied. We examined a total of 64 models in our candidate set, with the following covariates: TL at first capture, maximum temperature, season, maximum discharge, and area sampled. Survival estimates were highest in the spring (range of daily Φ = 0.9993–0.9995) and increased with greater TL at first capture. We also estimated increases in capture probability with increasing area sampled. We derived an annual λ of 0.9794, which indicates a slightly decreasing population. However, our λ estimate contained uncertainty that was likely increased due to the low recapture rates. Additional years of data could increase the accuracy of the λ estimate. In the meantime, we have provided insight into Stonecat population parameters that were otherwise unknown.Received December 22, 2015; accepted March 1, 2016 Published online June 29, 2016

Relationship between regional population and healthcare delivery in Japan.

In order to address regional inequality in healthcare delivery in Japan, healthcare districts were established in 1985. However, regional healthcare delivery has now become a national issue because of population migration and the aging population. In this study, the state of healthcare delivery at the district level is examined by analyzing population, the number of physicians, and the number of hospital beds. The results indicate a continuing disparity in healthcare delivery among districts. We find that the rate of change in population has a strong positive correlation with that in the number of physicians and a weak positive correlation with that in the number of hospital beds. In addition, principal component analysis is performed on three variables: the rate of change in population, the number of physicians per capita, and the number of hospital beds per capita. This analysis suggests that the two principal components contribute 90.1% of the information. The first principal component is thought to show the effect of the regulations on hospital beds. The second principal component is thought to show the capacity to recruit physicians. This study indicates that an adjustment to the regulations on hospital beds as well as physician allocation by public funds may be key to resolving the impending issue of regionally disproportionate healthcare delivery.

An evolutionary ecology perspective to address forest pathology challenges of today and tomorrow

AbstractKey messageIncreasing human impacts on forests, including unintentional movement of pathogens, climate change, and large-scale intensive plantations, are associated with an unprecedented rate of new diseases. An evolutionary ecology perspective can help address these challenges and provide direction for sustainable forest management.ContextForest pathology has historically relied on an ecological approach to understand and address the practical management of forest diseases. A widening of this perspective to include evolutionary considerations has been increasingly developed in response to the rising rates of genetic change in both pathogen populations and tree populations due to human activities.AimsHere, five topics for which the evolutionary perspective is especially relevant are highlighted.ResultsThe first relates to the evolutionary diversity of fungi and fungal-like organisms, with issues linked to the identification of species and their ecological niches. The second theme deals with the evolutionary processes that allow forest pathogens to adapt to new hosts after introductions or to become more virulent in homogeneous plantations. The third theme presents issues linked to disease resistance in tree breeding programs (e.g., growth-defense trade-offs) and proposes new criteria and methods for more durable resistance. The last two themes are dedicated to the biotic environment of the tree–pathogen system, namely, hyperparasites and tree microbiota, as possible solutions for health management.ConclusionWe conclude by highlighting three major conceptual advances brought by evolutionary biology, i.e., that (i) “not everything is everywhere”, (ii) evolution of pathogen populations can occur on short time scales, and (iii) the tree is a multitrophic community. We further translate these into a framework for immediate policy recommendations and future directions for research.

Demographic response of northern spotted owls to barred owl removal

ABSTRACTFederally listed as threatened in 1990 primarily because of habitat loss, the northern spotted owl (Strix occidentalis caurina) has continued to decline despite conservation efforts resulting in forested habitat being reserved throughout its range. Recently, there is growing evidence the congeneric invasive barred owl (Strix varia) may be responsible for the continued decline primarily by excluding spotted owls from their preferred habitat. We used a long‐term demographic study for spotted owls in coastal northern California as the basis for a pilot barred owl removal experiment. Our demography study used capture–recapture, reproductive output, and territory occupancy data collected from 1990 to 2013 to evaluate trends in vital rates and populations. We used a classic before‐after‐control‐impact (BACI) experimental design to investigate the demographic response of northern spotted owls to the lethal removal of barred owls. According to the best 2‐species dynamic occupancy model, there was no evidence of differences in barred or northern spotted owl occupancy prior to the initiation of the treatment (barred owl removal). After treatment, barred owl occupancy was lower in the treated relative to the untreated areas and spotted owl occupancy was higher relative to the untreated areas. Barred owl removal decreased spotted owl territory extinction rates but did not affect territory colonization rates. As a result, spotted owl occupancy increased in the treated area and continued to decline in the untreated areas. Prior to and after barred owl removal, there was no evidence that average fecundity differed on the 2 study areas. However, the greater number of occupied spotted owl sites on the treated areas resulted in greater productivity in the treated areas based on empirical counts of fledged young. Prior to removal, survival was declining at a rate of approximately 0.2% per year for treated and untreated areas. Following treatment, estimated survival was 0.859 for the treated areas and 0.822 for the untreated areas. Derived estimates of population change on both study areas showed the same general decline before removal with an estimated slope of –0.0036 per year. Following removal, the rate of population change on the treated areas increased to an average of 1.029 but decreased to an average of 0.870 on the untreated areas. The results from this first experiment demonstrated that lethal removal of barred owls allowed the recovery of northern spotted owl populations in the treated portions of our study area. If additional federally funded barred owl removal experiments provide similar results, this could be the foundation for development of a long‐term conservation strategy for northern spotted owls. © 2016 The Wildlife Society.

How fast is fast? Eco-evolutionary dynamics and rates of change in populations and phenotypes.

It is increasingly recognized that evolution may occur in ecological time. It is not clear, however, how fast evolution - or phenotypic change more generally - may be in comparison with the associated ecology, or whether systems with fast ecological dynamics generally have relatively fast rates of phenotypic change. We developed a new dataset on standardized rates of change in population size and phenotypic traits for a wide range of species and taxonomic groups. We show that rates of change in phenotypes are generally no more than 2/3, and on average about 1/4, the concurrent rates of change in population size. There was no relationship between rates of population change and rates of phenotypic change across systems. We also found that the variance of both phenotypic and ecological rates increased with the mean across studies following a power law with an exponent of two, while temporal variation in phenotypic rates was lower than in ecological rates. Our results are consistent with the view that ecology and evolution may occur at similar time scales, but clarify that only rarely do populations change as fast in traits as they do in abundance.

日本の地方都市における人口変化

Population trends of cities in rural regions of Japan are surveyed. First, population change rates during the period 2005–2010 of 401 cities in “Hokkaido and Tohoku,” “Hokuriku and Koshin-etsu,” “Chugoku and Shikoku,” and “Kyushu and Okinawa” regions are calculated. Few cities gained population, for example, Sapporo, Sendai, Fukuoka, and the satellite cities. On the other hand, cities that lost more than 5% of their populations are distributed in peripheral regions such as Sanriku Coast of Iwate and peninsulas and islands of west and south Kyushu. Generally, a positive relationship between population size of cities and those change rates is observed. Next, using long-term statistics, periods when cities in rural regions recorded peak populations are specified. The peaks tended to concentrate in two periods, that is, 1947–1955 and 2005–2010. Finally, cohort change rates are shown in 30 cities where prefectural government offices are located. Major cities such as Sapporo, Sendai, and Fukuoka have maintained stable inflows of young people since 1985. However, about one third of the prefectural capitals lost youngsters and received no populations of other age groups in recent years. From the viewpoint of population changes, almost all cities in rural regions in Japan are in a challenging situation. The “foothold” or “hub cities” in rural regions became exceptions in Japan.

Demografski razvoj otoka Brača i sklonost otočana iseljavanju

Demografski razvoj otoka Brača i sklonost otočana iseljavanju

The effects of habitat, climate, and Barred Owls on long-term demography of Northern Spotted Owls

ABSTRACT Estimates of species' vital rates and an understanding of the factors affecting those parameters over time and space can provide crucial information for management and conservation. We used mark–recapture, reproductive output, and territory occupancy data collected during 1985–2013 to evaluate population processes of Northern Spotted Owls (Strix occidentalis caurina) in 11 study areas in Washington, Oregon, and northern California, USA. We estimated apparent survival, fecundity, recruitment, rate of population change, and local extinction and colonization rates, and investigated relationships between these parameters and the amount of suitable habitat, local and regional variation in meteorological conditions, and competition with Barred Owls (Strix varia). Data were analyzed for each area separately and in a meta-analysis of all areas combined, following a strict protocol for data collection, preparation, and analysis. We used mixed effects linear models for analyses of fecundity, Cormack-Jolly-...