Geology topics

James D. Nichols

Publications and source records attributed to James D. Nichols.

At least 127 records · Page 7Linked to original sources

USGS1998

Estimating rates of local species extinction, colonization and turnover in animal communities

Species richness has been identified as a useful state variable for conservation and management purposes. Changes in richness over time provide a basis for predicting and evaluating community responses to management, to natural disturbance, and to changes in factors such as community composition (e.g., the removal of a keystone species). Probabilistic capture-recapture models have been used recently to estimate species richness from species count and presence-absence data. These models do not require the common assumption that all species are detected in sampling efforts. We extend this approach to the development of estimators useful for studying the vital rates responsible for changes in animal communities over time; rates of local species extinction, turnover, and colonization. Our approach to estimation is based on capture-recapture models for closed animal populations that permit heterogeneity in detection probabilities among the different species in the sampled community. We have developed a computer program, COMDYN, to compute many of these estimators and associated bootstrap variances. Analyses using data from the North American Breeding Bird Survey (BBS) suggested that the estimators performed reasonably well. We recommend estimators based on probabilistic modeling for future work on community responses to management efforts as well as on basic questions about community dynamics.

Ecological Applications↗

USGS1997

Estimating temporary emigration using capture-recapture data with Pollock's robust design

Statistical inference for capture–recapture studies of open animal populations typically relies on the assumption that all emigration from the studied population is permanent. However, there are many instances in which this assumption is unlikely to be met. We define two general models for the process of temporary emigration: completely random and Markovian. We then consider effects of these two types of temporary emigration on Jolly–Seber estimators and on estimators arising from the full-likelihood approach to robust design data. Capture–recapture data arising from Pollock’s robust design provide the basis for obtaining unbiased estimates of demographic parameters in the presence of temporary emigration, and for estimating the probability of temporary emigration. We present a likelihood-based approach to dealing with temporary emigration that permits estimation under different models of temporary emigration and yields tests for completely random and Markovian emigration. In addition, we use the relationship between capture probability estimates based on closed and open models under completely random temporary emigration to derive three ad hoc estimators for the probability of temporary emigration. Two of these should be especially useful in situations where capture probabilities are heterogeneous among individual animals. Ad hoc and full-likelihood estimators are illustrated for small-mammal capture–recapture data sets. We believe that these models and estimators will be useful for testing hypotheses about the process of temporary emigration, for estimating demographic parameters in the presence of temporary emigration, and for estimating probabilities of temporary emigration. These latter estimates are frequently of ecological interest as indicators of animal movement and, in some sampling situations, as direct estimates of breeding probabilities and proportions.

Ecology↗

USGS1997

Tests for senescent decline in annual survival probabilities of common pochards, Aythya ferina

Senescent decline in survival probabilities of animals is a topic about which much has been written but little is known. Here, we present formal tests of senescence hypotheses, using 1373 recaptures from 8877 duckling (age 0) and 504 yearling Common Pochards (Aythya ferina) banded at a Latvian study site, 1975-1992. The tests are based on capture-recapture models that explicitly incorporate sampling probabilities that, themselves, may exhibit timeand age-specific variation. The tests provided no evidence of senescent decline in survival probabilities for this species. Power of the most useful test was low for gradual declines in annual survival probability with age, but good for steeper declines. We recommend use of this type of capture-recapture modeling and analysis for other investigations of senescence in animal survival rates.

Ecology↗

USGS1997

Capture-recapture analysis of a wintering black-capped chickadee population in Connecticut, 1958-1993

We investigated the dynamics of a wintering population of Black-capped Chickadees ( Parus atricapillus ) using data from a long-term capture-recapture study. Goodness-of-fit and likelihood-ratio tests indicated that the standard Jolly-Seber model was inadequate for the data, so we explored different parameterizations of a model in which survival probability for new captures differed from that of previously marked birds. One possible explanation for the lower local survival rate of new captures is that some of the birds were transients that had no chance of being recaptured. Average survival probability over the entire period was 0.62, and the estimated fraction of transients among unmarked birds was 0.27. We found evidence that chickadee survival rates were lower in years immediately following establishment of the Tufted Titmouse ( Parus bicolor ) as a territorial species (after 1967) than during years immediately preceding this event. We found no evidence that chickadee survival rates were lower in the years immediately following establishment of territorial raptors (after 1984) than during preceding years. Evidence suggested a long-term decline in survival probability from 1959 to 1991.

The Auk↗

USGS1995

Managing North American waterfowl in the face of uncertainty

Informed management of waterfowl (or any animal population) requires management goals and objectives, the ability to implement management actions, periodic information about population and goal-related varlables, and knowledge of effects of management actions on population and goal-related variables. In North America, international treaties mandate a primary objective of protecting migratory bird populations, with a secondary objective of providing hunting opportunity in a manner compatible with such protection. Through the years, annual establishment of hunting regulations and acquisition and man-agement of habitat have been the primary management actions taken by federal agencies. Various information-gathering programs were established and, by the 1960s, had developed into arguably the best monitoring system in the world for continentally distributed animal populations. Retrospective analyses using estimates from this monitoring system have been used to investigate effects of management actions on waterfowl population and harvest dynamics, but key relationships arc still characterized by uncertainty. We recommend actively adaptive management as an approach that can meet short-term harvest objectives, while reducing uncertainty and ensuring sustainable populations over the long-term.

Annual Review of Ecology and Systematics↗

USGS1995

Demography of birds in a neotropical forest: Effects of allometry, taxonomy, and ecology

Comparative demographic studies of terrestrial vertebrates have included few samples of species from tropical forests. We analyzed 9 yr of mark—recapture data and estimated demographic parameters for 25 species of birds inhabiting lowland forests in central Panama. These species were all songbirds (Order Passeriformes) ranging in mass from 7 to 57 g. Using Jolly—Seber stochastic models for open populations, we estimated annual survival rate, population size, and recruitment between sampling periods for each species. We then explored relationships between these parameters and attributes such as body size, phylogenetic affiliation, foraging guild, and social behavior. Larger birds had comparatively long life—spans and low recruitment, but body size was not associated with population size. After adjusting for effects of body size, we found no association between phylogenetic affiliation and any demographic trait. Ecological attributes, especially foraging guild, were more clearly associated with interspecific variation in all demographic traits. Ant—followers had comparatively long life—spans, but species that participate in flocks did not live longer than solitary species. The allometric associations we observed were consistent with those demonstrated in other studies of vertebrates; thus, these relationships appear to be robust. Our findings that ecological factors were more influential than phylogenetic affiliation contrasts with comparative studies of temperate—zone birds and suggests that the relative importance of environmental vs. historical factors varies geographically.

Ecology↗

USGS1995

Spring-summer survival rates of yearling versus adult mallard females

Knowledge of the timing, magnitude, and cause of mortality in wildlife populations is imperative for developing management strategies that protect or improve the status of these populations. Age- and sex-specific population parameter estimates provide the most useful information for this purpose. Numerous studies have provided information about survival rates in mallards ( Anas platyrhynchos ), but little is known about age-related differences in female survival during the breeding period. We examined band-recovery data for female mallards banded in southern portions of Alberta, Saskatchewan, and Manitoba during spring and summer 1981-85. We used band-recovery models to test the hypothesis that yearling females would exhibit higher survival compared with that of older females during spring-summer. There was evidence ( P = 0.08) that spring-summer survival rates of yearling females (0.728) were higher than that of older females (0.574). These findings support the hypothesis that age-specific differences in nesting behavior (e.g., later nest initiation and fewer nesting attempts by yearlings) influence losses to predators and are responsible for the difference in spring-summer survival. Management treatments that increase nest success, and consequently reduce the need for prolonged nesting, will increase mallard survival during spring-summer.

Alberta, Manitoba, Saskatchewan↗

USGS1995

Geographic variation in band reporting rates for mallards based on reward banding

We conducted a reward band study on mallards ( Anas platyrhynchos ) to estimate and test hypotheses about sources of variation in band reporting rate. We banded 25,398 mallards with standard and 100 reward bands (3 mallards banded with standard bands for every reward-banded mallard) during preseason (Jul-Sep), 1988. We used a series of multinomial models to model the resulting 2,776 band recoveries from 1988 to 1991. Estimates of reporting rate for males shot in 10 harvest areas ranged from 0.29 to 0.46 and averaged 0.38 (SE = 0.020). We found evidence ( P < 0.01) of geographic variation in reporting rates, but not of smooth latitudinal or longitudinal gradients. There was evidence ( P = 0.07) of lower reporting rates for females than males, especially in prairie Canada and the Central Flyway. Except for young males in the northern Atlantic Flyway, estimated harvest rates were lower than historical estimates, as expected from recent restrictive hunting regulations. Patterns of geographic and agesex variation in harvest rates were similar to those obtained using historical band-recovery data.

Journal of Wildlife Management↗

USGS1995

Banding reference areas and survival rates of green-winged teal, 1950-1989

The green-winged teal ( Anas crecca carolinensis ) is an important harvest species, yet we know relatively little about its population ecology. We investigated aspects of green-winged teal population ecology of potential importance to waterfowl managers. We used recoveries of green-winged teal banded during winter (1950-89) to establish banding reference areas and estimate survival and band recovery rates. We used cluster analysis based on similarities in recovery patterns to group banding degree blocks into 8 minor and 5 major reference areas describing the principal wintering range of green-winged teal in North America. We then estimated survival and recovery rates of green-winged teal banded in these areas. Mean annual survival rate estimates across years and reference areas were similar (P > 0.05) for males (0.55, SE = 0.022) and females (0.51, SE = 0.057). Mean annual recovery rate estimates were larger for males (0.033, SE = 0.0017) than for females (0.024, SE = 0.0024) ( P < 0.01). There was little evidence of temporal variation in survival or recovery rates for most datasets. There was evidence of geographic variation in survival rates among major reference areas for males ( P = 0.04) but not for females ( P = 0.30). We recommend that analyses be conducted on greenwinged teal banded during preseason to further investigate possible sex specificity of survival rates and to address questions about the relationship between harvest rates and survival.

California, Georgia, Kansas, Nevada, Ohio, Virgini↗

USGS1995

Estimating annual survival and movement rates of adults within a metapopulation of roseate terns

Several multistratum capture—recapture models were used to test various hypotheses about possible geographic and temporal variation in survival, movement, and recapture/resighting probabilities of 2399 adult Roseate Terns (Sterna dougallii) color—banded from 1988 to 1992 at the sites of the four largest breeding colonies of this species in the northeastern USA. Linear—logistic ultrastructural models also were developed to investigate possible correlates of geographic variation in movement probabilities. Based on goodness—of—fit tests and comparisons of Akaike's Information Criterion (AIC) values, the fully parameterized model (Model A) with time— and location—specific survival, movement, and capture probabilities, was selected as the most appropriate model for this metapopulation structure. With almost all movement accounted for, on average >90% of the surviving adults from each colony site returned to the same site the following year. Variations in movement probabilities were more closely associated with the identity of the destination colony site than with either the identity of the colony site of origin or the distance between colony sites. The average annual survival estimates (0.74—0.84) of terns from all four sites indicate a high rate of annual mortality relative to that of other species of marine birds.

Ecology↗

USGS1994

Estimating breeding proportions and testing hypotheses about costs of reproduction with capture-recapture data

The proportion of animals in a population that breeds is an important determinant of population growth rate. Usual estimates of this quantity from field sampling data assume that the probability of appearing in the capture or count statistic is the same for animals that do and do not breed. A similar assumption is required by most existing methods used to test ecologically interesting hypotheses about reproductive costs using field sampling data. However, in many field sampling situations breeding and nonbreeding animals are likely to exhibit different probabilities of being seen or caught. In this paper, we propose the use of multistate capture-recapture models for these estimation and testing problems. This methodology permits a formal test of the hypothesis of equal capture/sighting probabilities for breeding and nonbreeding individuals. Two estimators of breeding proportion (and associated standard errors) are presented, one for the case of equal capture probabilities and one for the case of unequal capture probabilities. The multistate modeling framework also yields formal tests of hypotheses about reproductive costs to future reproduction or survival or both fitness components. The general methodology is illustrated using capture-recapture data on female meadow voles, Microtus pennsylvanicus. Resulting estimates of the proportion of reproductively active females showed strong seasonal variation, as expected, with low breeding proportions in midwinter. We found no evidence of reproductive costs extracted in subsequent survival or reproduction. We believe that this methodological framework has wide application to problems in animal ecology concerning breeding proportions and phenotypic reproductive costs.

Ecology↗

USGS1994

Retention of web tags and plasticine-filled leg bands applied to day-old ducklings

A new plasticine-filled leg band was developed for use in banding dayold ducklings. These bands permit inference about early survival that is not possible from banding of older young in standard operations. Two double-marking experiments with web tags and the new leg bands indicated a high retention rate for the leg bands. In contrast, several web tags were lost, permitting an analysis directed at sources of variation in web tag retention rates. We found retention rates of web tags to be higher for diving ducks ( Aythya ) than for dabbling ducks ( Anas ), and higher for tags placed the web interior than for those applied to the web edge. However, we recommend that the new plasticine-filled leg bands be used in place of web tags because of their higher retention rates and presumably greater visibility to hunters. We believe they offer great potential for new studies of duckling survival and distribution.

Engure Marsh↗

USGS1992

Estimating transition probabilities for stage-based population projection matrices using capture-recapture data

In stage—based demography, animals are often categorized into size (or mass) classes, and size—based probabilities of surviving and changing mass classes must be estimated before demographic analyses can be conducted. In this paper, we develop two procedures for the estimation of mass transition probabilities from capture—recapture data. The first approach uses a multistate capture—recapture model that is parameterized directly with the transition probabilities of interest. Maximum likelihood estimates are then obtained numerically using program SURVIV. The second approach involvesa modification of Pollock's robust design. Estimation proceeds by conditioning on animals caught in a particualr class at time i, and then using closed models to estimate the number of these that are alive in other classes at i + 1. Both methods are illustrated by application to meadow vole, Microtus pennsylvanicus, capture—recapture data. The two methods produced reasonable estimates that were similar. Advantages of these two approaches include the directness of estimation, the absence of need for restrictive assumptions about the independence of survival and growth, the testability of assumptions, and the testability of related hypotheses of ecological interest (e.g., the hypothesis of temporal variation in transition probabilities).

Ecology↗

USGS1992

Survival of cackling Canada geese, 1982-1988

We estimated seasonal and annual survival rates of cackling Canada geese ( Branta canadensis minima ) for the period 1982-1989 to identify periods of high mortality and assess effects of harvest management decisions. We tested hypotheses about age- and sex specific variation in survival, seasonal variation in survival rates, and variation in survival between years in which hunting seasons were open and closed. Geese were marked with individually identifiable neckbands and observed from autumn through spring. We used these data to estimate survival rates for 3-month periods in early (EW) and late (LW) winter and a 6-month period in summer (SU). Mean annual survival rates of immature females were lower than those of adults over the entire study. Survival rates of immature males were lower than those of adults during the 2 years with sport hunting seasons. We found no evidence of sex-specific differences in seasonal or annual survival rates of immature geese. Mean survival rates of adult males and females were similar during EW and LW, but there was evidence of higher survival of females during SU. Annual survival rates of adult females were higher than those of adult males. Mean annual survival rates of adult females and immatures of both sexes were lower in the years during which sport hunting was permitted. Tests for different survival rates in years before and after an agreement with the Eskimos to cease summer hunting yielded equivocal results.

Alaska, California↗

USGS1992

Annual survival rates of adult and immature eastern population tundra swans

Tundra swans ( Cygnus columbianus) of the eastern population were neckbanded in Maryland, North Carolina, and Alaska from 1966 through 1990. These swans were resighted and recaptured during autumn, winter, and spring, 1966-1990. Although the original motivation for this study involved swan movements, we wanted to use the resulting data to test hypotheses about sources of variation in swan survival rates. Recaptures of legbanded and neckbanded swans permitted us to estimate neckband loss rates, which were found to vary with age and sex of swans, and number of years since initial application. Estimates of annual neckband retention rate ranged from about 0.50 for adult male swans ≥ 2 years after initial neckbanding to > 0.96 for immature swans and adult females the first year following neckbanding. This variation in neckband loss rates prevented the simple correction of survival estimates to account for such loss. Consequently, we developed a series of multinomial models parameterized with survival, sighting, and neckband retention probabilities for use with the recapture and resighting data.

Alaska, Maryland, North Carolina↗

USGS1991

Effect of hunting on annual survival of grey ducks in New Zealand

We used band recovery data from grey ducks ( Anas superciliosa ) banded in New Zealand between 1957 and 1974 to test 2 null hypotheses: (1) hunting mortality is completely additive to natural sources of mortality, and (2) hunting mortality is completely compensated by changes in natural mortality. We modeled annual survival as a function of survival in the absence of hunting and the probability of death from hunting. The complete compensation hypothesis was rejected, but we were unable to reject the completely additive hypothesis. There was no evidence of sex- or age-specificity for the relationship between kill rate and annual survival rate. We used simulated data to evaluate model performance. Parameter estimates were unbiased despite the inclusion of estimates that lay outside the bounds of the parameter space, although model-based variance estimates were consistently less than empirical variances. Our results imply that harvest-restrictions may be useful in effecting change in annual survival rates of grey ducks.

Journal of Wildlife Management↗

USGS1991

Survival and band recovery rates of sympatric grey ducks and mallards in New Zealand

We used band recovery data from grey ducks ( Anas superciliosa ) and mallards. ( A. platyrhynchos ) banded sympatrically during 1957-74 to estimate annual survival and recovery rates. Young birds tended to have higher recovery rates and lower survival rates than adults for both species. Both species showed strong evidence of year-to-year variation in annual survival rates. Survival rates of male mallards were higher than those in females, as is typical for this species in North America, but there was no evidence of sex-specific survival differences in grey ducks. Recovery rate estimates for grey ducks were high and were significantly higher than those for mallards. However, survival rates did not differ significantly between the 2 species within any age-sex class. The similar survival rates, when mallard populations were increasing and grey ducks were decreasing, suggest that mallard reproductive rates have been greater than those of grey ducks.

Journal of Wildlife Management↗

USGS1991

Band reporting rates for mallards with reward bands of different dollar values

Adult male mallards ( Anas platyrhynchos ) were banded in summer 1987 with reward bands of different dollar values (0-$400) to determine the lowest dollar value that would yield a reporting rate approaching 1.0. During the 1987-88 and 1988-89 hunting seasons, rewards of between 50 and $100 were required to yield a reporting rate near 1.0. We estimated reporting rate of standard bands to be 0.32. Reward bands with 5 and $10 values produced reporting rates that were 1.5-2.0 times as large as those of standard bands. We developed a linear-logistic model to predict reporting rate as a function of the dollar value of reward bands.

Manitoba, Saskatchewan↗