Sustainable management of exploited populations benefits from integrating demographic and genetic considerations into assessments, as both play a role in determining harvest yields and population persistence. This is especially important in populations subject to size-selective harvest, because size selective harvesting has the potential to result in significant demographic, life-history, and genetic changes. We investigated harvest-induced changes in the effective number of breeders ( ) for introduced brook trout populations (Salvelinus fontinalis) in alpine lakes from western Canada. Three populations were subject to three years of size-selective harvesting, while three control populations experienced no harvest. The  decreased consistently across all harvested populations (on average 60.8%) but fluctuated in control populations. There were no consistent changes in  between control or harvest populations, but one harvest population experienced a decrease in  of 63.2%. The /  ratio inc...

Many animal populations are subject to hunting or fishing in the wild. Detailed knowledge of demographic parameters (e.g. survival, reproduction) and temporal dynamics of such populations is crucial for sustainable management. Despite their relevance for management decisions, structure and size of exploited populations are often not known, and data limited. Recently, joint analysis of different types of demographic data, such as population counts, reproductive data and capture-mark-recapture data, within integrated population models (IPMs) has gained much popularity as it may allow estimating population size and structure, as well as key demographic rates, while fully accounting for uncertainty. IPMs built so far for exploited populations have typically been built as age-structured population models. However, the age of harvested individuals is usually difficult and/or costly to assess and therefore often not available. Here, we introduce an IPM structured by body size classes, which al...

Data and R Code for manuscript titled "Population Dynamics and Harvest Management of Eastern Mallards"

Estimates of range-wide abundance, harvest, and harvest rate are fundamental for sound inferences about the role of exploitation in the dynamics of free-ranging wildlife populations, but reliability of existing survey methods for abundance estimation is rarely assessed using alternative approaches. North American mallard populations have been surveyed each spring since 1955 using internationally coordinated aerial surveys, but population size can also be estimated with Lincoln's method using banding and harvest data. We estimated late summer population size of adult and juvenile male and female mallards in western, midcontinent, and eastern North America using Lincoln's method of dividing (i) total estimated harvest, H, by estimated harvest rate, h, calculated as (ii) direct band recovery rate, f, divided by the (iii) band reporting rate, p. Our goal was to compare estimates based on Lincoln's method with traditional estimates based on aerial surveys. Lincoln estimates of adult males and females alive in the period June–September were 4.0 (range: 2.5–5.9), 1.8 (range: 0.6–3.0), and 1.8 (range: 1.3–2.7) times larger than respective aerial survey estimates for the western, midcontinent, and eastern mallard populations, and the two population estimates were only modestly correlated with each other (western: r = 0.70, 1993–2011; midcontinent: r = 0.54, 1961–2011; eastern: r = 0.50, 1993–2011). Higher Lincoln estimates are predictable given that the geographic scope of inference from Lincoln estimates is the entire population range, whereas sampling frames for aerial surveys are incomplete. Although each estimation method has a number of important potential biases, our review suggests that underestimation of total population size by aerial surveys is the most likely explanation. In addition to providing measures of total abundance, Lincoln's method provides estimates of fecundity and population sex ratio and could be used in integrated population models to provide greater insights about population dynamics and management of North American mallards and most other harvested species.

Data and R script for developing population model for black swans at Te Waihora in 2018, as presented in Herse et al. "A demographic model to support customary management of a culturally important waterfowl species."

[Project 3.2]

1. Landscape changes are happening at an unprecedented pace, and together with high levels of wildlife harvesting humans have a large effect on wildlife populations. A thorough knowledge of their combined influence on individual fitness is important in order to understand factors affecting population dynamics. 2. The goal of the study was to assess the individual consistency in the use of risky habitat types, and how habitat use was related to fitness components and life-history strategies. 3. Using data from a closely monitored and harvested population of moose (Alces alces), we examined how individual variation in offspring size, reproduction, and survival was related to the use of open grasslands; a habitat type that offers high-quality forage during summer, but at the cost of being more exposed to hunters in autumn. Use of this habitat type may therefore involve a trade-off between high mortality risk and forage maximization. 4. There was high repeatability in habitat use, which suggest consistent behaviour within individuals. Offspring number and weight was positively related to the mothers’ use of open grasslands, whereas the probability of surviving the subsequent harvest season was negatively related to the use of the same habitat type. As a consequence, we found a non-significant relationship between habitat use and lifetime fitness. 5. The study suggest that harvesting, even if intended to be nonselective with regard to phenotypes, may be selective towards animals with specific behaviour and life-history strategies. As a consequence, harvesting can alter the life-history composition of the population and target life-history strategies that would be beneficial for individual fitness and population growth in the absence of hunting.

Sustainable harvesting of wild populations relies on evidence-based knowledge to predict harvesting outcomes for species and the ecosystems they inhabit. Although harvesting may elicit compensatory density-dependence, it is generally size-selective, which induces additional pressures that are challenging to forecast. Furthermore, responses to harvest may be population-specific and whether generalizable patterns exist remains unclear. Taking advantage of Parks Canada’s mandate to remove introduced brook trout (Salvelinus fontinalis) to restore alpine lakes in Canadian parks, we experimentally applied standardized size-selective harvesting rates (the largest ~64% annually) for three consecutive summers in five populations with different initial size structures. Four unharvested populations were used as controls. At reduced densities, harvested and control populations exhibited similar density-dependent increases in specific growth, juvenile survival, and earlier maturation....

This dataset includes total annual harvest of all wild steelhead encountered, including directed and incidental, in all commercial, sport, and ceremonial and subsistence fisheries conducted within the Skagit River.

The interaction between environmental variation and population dynamics is of major importance, particularly for managed and economically important species, and especially given contemporary changes in climate variability. Recent analyses of exploited animal populations contested whether exploitation or environmental variation has the greatest influence on the stability of population dynamics, with consequences for variation in yield and extinction risk. Theoretical studies however have shown that harvesting can increase or decrease population variability depending on environmental variation, and requested controlled empirical studies to test predictions. Here, we use an invertebrate model species in experimental microcosms to explore the interaction between selective harvesting and environmental variation in food availability in affecting the variability of stage-structured animal populations over 20 generations. In a constant food environment, harvesting adults had negligible impact on population variability or population size, but in the variable food environments, harvesting adults increased population variability and reduced its size. The impact of harvesting on population variability differed between proportional and threshold harvesting, between randomly and periodically varying environments, and at different points of the time series. Our study suggests that predicting the responses to selective harvesting is sensitive to the demographic structures and processes that emerge in environments with different patterns of environmental variation.

Goose management in Europe is faced by multiple challenges, as some species are declining and in need of conservation actions, while other populations have become very abundant, resulting in calls for increased harvest.

Sweden has long-term series of harvest data and counts of breeding and autumn-staging geese. We used national data (indices) for greylag goose, bean goose, and Canada goose to study shifts in temporal trends and correlative patterns, and to infer possible causal links between harvest and population trends. Our study provides an opportunity to guide management given the data collected within the present monitoring, as well as to suggest improvements for future data collection.

The populations of greylag and Canada geese increased in Sweden 1979–2018, but this long-term trend included a recent decrease in the latter species. Bean goose breeding index decreased, whilst staging numbers and harvest varied with no clear long-term trend. For Canada goose, our analysis suggests that harvest may affect population growth negatively. For bean goose and greylag goose we could not detect any effect of harvest on autumn counts the following year.

We find that the present data and analysis of coherence may suffice as basis for decisions for the current management situation in Sweden with its rather unspecific goals for greylag (very abundant ) and Canada goose (invasive species) populations. However, for management of bean geese, with international concerns of over harvest, data lack crucial information. For future management challenges, with more explicit goals, for all goose species we advocate information that is more precise. Data such as hunting effort, age-structure of goose populations, and mark-recapture data to estimate survival and population size, is needed to feed predictive population models guiding future Swedish and European goose management.

Methods We based this study on data from three independent long-term monitoring programs in Sweden, providing annual data of: 1) breeding season abundance (1998-2017), 2) autumn staging counts (1978-2017) and 3) national harvest estimates (1978-2017). These datasets are here used as indices for breeding and autumn staging population development and changes in harvest levels respectively, and represent the available nation-wide monitoring of goose populations in Sweden.

Harvest of Brazil nuts from the large, iconic tree Bertholletia excelsa generates substantial income for smallholders, providing a strong incentive to conserve the mature forests where it grows. Although much previous work has focused on the impact of nut harvest on new seedling recruits into B. excelsa populations, the connection between harvest rates and long-term population stability is still unclear. Moreover, there is additional uncertainty for Brazil nut management in terms of population response to climate change and other anthropogenic influences. We drew on 14 years of research in two sites in Acre, Brazil with different B. excelsa nut harvest intensities (39% and 81%), to produce stochastic and deterministic matrix population models which incorporated parameter uncertainty in vital rates. Adult abundance was projected to remain close to the current observed abundance or higher through the next 50 years. Elasticity analyses revealed that the asymptotic population growth rate (λ...

Survey and detection data from spring roadside drumming surveys of ruffed grouse in North Georgia. Data for Lewis et al. Abundance and distribution of ruffed grouse (Bonasa umbellus) at the southern periphery of the range: Implications for harvest management.

Harvesting and culling are methods used to monitor and manage wildlife diseases. An important consequence of these practices is a change in the genetic dynamics of affected populations that may threaten their long-term viability. The effective population size (Ne) is a fundamental parameter for describing such changes as it determines the amount of genetic drift in a population. Here, we estimate Ne of a harvested wild reindeer population in Norway. Then we use simulations to investigate the genetic consequences of management efforts for handling a recent spread of chronic wasting disease, including increased adult male harvest and population decimation. The Ne/N ratio in this population was found to be 0.124 at the end of the study period, compared to 0.239 in the preceding 14-year period. The difference was caused by increased harvest rates with a high proportion of adult males (older than 2.5 years) being shot (15.2 % in 2005-2018 and 44.8 % in 2021). Increased harvest rates decreased Ne in the simulations, but less sex-biased harvest strategies had a lower negative impact. For harvest strategies that yield stable population dynamics, shifting the harvest from calves to adult males and females increased Ne. Population decimation always resulted in decreased genetic variation in the population, with higher loss of heterozygosity and rare alleles with more severe decimation or longer periods of low population size. A very high proportion of males in the harvest had the most severe consequences for the loss of genetic variation. This study clearly shows how the effects of harvest strategies and changes in population size interact to determine the genetic drift of a managed population. The long-term genetic viability of wildlife populations subject to disease will also depend on the population impacts of the disease and how these interact with management actions. Methods Data collectionThe data was collected from the wild reindeer population at Hardangervidda in Southern Norway (60°09’55’’ N, 07°27’58’’ E). The Hardangervidda population is subject to annual harvest before the rut in late summer or the beginning of autumn (August-September). Generally, hunters do not differentiate between female and male calves, and it is also difficult to determine the sex of yearlings (1.5 years old) during hunting. Thus, harvest quotas generally separate between calves (0.5 years old), females (2.5 years and older), yearlings (females and males 1.5 years old), and free licenses (animals of any age and sex). The latter category is typically used to shoot adult males (2.5 years and older), as their size and status as trophy is considered attractive by hunters. Data on the number of harvested animals in each of the six categories (calves, yearlings, and adults of both sexes) were collected as reported by hunters. Four different annual surveys are performed throughout the year to monitor the population size and structure. First, a minimum estimate for the population size is made using flight transects during mid-winter (January-March), where all observed groups of reindeer are photographed and counted. Second, the annual calf production is estimated using flight transects during summer (late June to mid-July), where a subset of groups with females, calves, and yearling males are photographed and the ratio of calves to adult females and yearlings of both sexes are calculated. Adult males generally aggregate in separate groups in other areas at this time of the year. Third, data is recorded on the number of calves, yearlings, and adults of both sexes that are shot during the harvest (August-September). Finally, the population age and sex structure are estimated using ground surveys just after the harvest (September-October). At this time of the year the reindeer aggregate in groups with both sexes and can be classified into age and sex classes (calves, females, yearling males, and adult males). Data on population sizes in the years 2005-2021 were collected from an established Bayesian integrated population model which uses data from these four surveys for this population (Viljugrein et al. 2023). Additional dataAdditional data on fertility for females, average summer survival for calves, and survival for adult animals in the Hardangervidda population were collected from Mysterud et al. (2020), data on mating skew for male reindeer were collected from Røed et al. (2005), data on primary sex ratio was collected from Loison and Strand (2005) and data on the distribution of age-specific fertilities were collected from Skogland (1985, 1989). These additional data are provided in the main text of the publication. References

Loison, A., Strand, O. 2005. Allometry and variability of resource allocation to reproduction in a wild reindeer population. Behavioural Ecology, 16: 624-633. Mysterud, A., Hopp, P., Alvseike, K.R., Benestad, S.L., Nilsen, E.B., Rolandsen, C.M., Strand, O., Våge, J., Viljugrein, H. 2020. Hunting strategies to increase detection of chronic wasting disease in cervids. Nature Communications, 11: 4392. Røed, K.H., Holand, Ø., Gjøstein, H., Hansen, H. 2005. Variation in male reproductive success in a wild population of reindeer. Journal of Wildlife Management, 69: 1163-1170. Skogstad, T. 1985. The effects of density-dependent resource limitations on the demography of wild reindeer. Journal of Animal Ecology, 54: 359-374. Skogstad, T. 1989. Natural selection of wild reindeer life history traits by food limitation and predation. Oikos, 55: 101-110. Viljugrein, H. 2023. Data and Figure-Scripts for the Paper ‘An Infectious Disease Outbreak and Increased Mortality in Wild Alpine Reindeer’. Zenodo. doi: 10.5281/zenodo.7624490

Prior distribution and hyperparameters for a Bayesian integrated population model of white-tailed deer in Tennessee using harvest data. Mean and standard deviation (SD) are specified on the complementary log-log (cloglog) scale for natural survival, hunting survival, and reporting rates, and on the log scale for recruitment rates. Age-specific differences in survival and reporting rates were modeled using log-hazard ratio (LHR) offsets, which were given weakly informative normal priors. Standard deviations for random effects were modeled as normal with mean 0 and SD estimated from Gamma-distributed priors. Prior-posterior overlap (for SD parameter the order is female; male) was used to evaluate priors, and when overlap was > 35% we calculated data-agreement criterion (DAC).

The American alligator (Alligator mississippiensis) is a species of ecological and economic importance in the southeastern United States. Within South Carolina, alligators are subject to private and public harvest programs, as well as nuisance removal. These management activities can have different impacts across alligator size classes that may not be apparent through widely-used monitoring techniques such as nightlight surveys. We synthesized multiple datasets within an integrated population model (IPM) to estimate size class-specific survival and abundance estimates, that would not be estimable through separate, non-integrated modeling frameworks. The IPM framework included a multistate mark-recapture-recovery model that used mark-recapture-recovery data from the Tom Yawkey Wildlife Center and growth transition probabilities that were estimated outside of the IPM framework. The IPM also included a state-space count model, which used nightlight survey counts of alligtaors from two survey routes: 1) Great Pee Dee and Waccamaw Rivers; and 2) South Santee Rivers. The IPM modeling framework also used mean clutch size data from the Tom Yawkey Wildlife Center and public and private harvest data within the state model. Lastly, we evaluated the effects of capture effort on capture probability, as well as the effects of water temperature and relative water level on count detection probability, and provide all covariate datasets. Our IPM framework determined that size class-specific survival rates were relatively high for all non-hatchling size classes, and abundance trends differed between the two nightlight survey sites.

Wildlife harvest remains a conservation concern for many species and assessing patterns of harvest can provide insights on sustainability and inform management. Polar bears (Ursus maritimus) are harvested over a large part of their range by local people. The species has a history of unsustainable harvest that was largely rectified by an international agreement that required science-based management. The objective of our study was to examine the temporal patterns in the number of polar bears harvested, harvest sex ratios, and harvest rates from 1970 to 2018. We analyzed data from 39,049 harvested polar bears (annual mean 797 bears) collected from 1970 to 2018. Harvest varied across populations and times that reflect varying management objectives, episodic events, and changes based on new population estimates. More males than females were harvested with an overall M:F sex ratio of 1.84. Harvest varied by jurisdiction with 68.0% of bears harvested in Canada, 18.0% in Greenland, 11.8% in the USA, and 2.2% in Norway. Harvest rate was often near the 4.5% target rate. Where data allowed harvest rate estimation, the target rate was exceeded in 11 of 13 populations with 1–5 populations per year above the target since 1978. Harvest rates at times were up to 15.9% of the estimated population size suggesting rare episodes of severe over-harvest. Harvest rate was unrelated to a proxy for ecosystem productivity (area of continental shelf within each population) but was correlated with prey diversity. In the last 5–10 years, monitored populations all had harvest rates near sustainable limits, suggesting improvements in management. Polar bear harvest management has reduced the threat it once posed to the species. However, infrequent estimates of abundance, new management objectives, and climate change have raised new concerns about the effects of harvest.

U.S. Census Bureau QuickFacts statistics for Harvest CDP, Alabama. QuickFacts data are derived from: Population Estimates, American Community Survey, Census of Population and Housing, Current Population Survey, Small Area Health Insurance Estimates, Small Area Income and Poverty Estimates, State and County Housing Unit Estimates, County Business Patterns, Nonemployer Statistics, Economic Census, Survey of Business Owners, Building Permits.

Median abundance of deer and density (deer per km2) with 90% credible intervals (CRI) for 2023 from an integrated population model based on harvest data from 2005 to 2023 by deer management unit (DMU) in Tennessee.

See the manuscript for details on how the dataset was collected and processed.

This data file is in long format, comprising time series of hunter abundance and behavior and duck abundance. Hunter information varies by administrative flyway (Mississippi and Central), whereas duck population abundance is summarized for both the Prairie Pothole Region and the continent. Duck information for the Prairie Pothole Region is for the U.S. portion only (Strata 41-49 of the May waterfowl survey) and for 12 duck species, mallard, American wigeon, blue-winged teal, canvasback, gadwall, lesser and greater scaup, green-winged teal, northern pintail, northern shoveler, redhead, ring-necked duck, and ruddy duck.