scholarly journals Natal Dispersal in the Cooperatively Breeding Acorn Woodpecker

The Condor ◽  
2000 ◽  
Vol 102 (3) ◽  
pp. 492-502 ◽  
Author(s):  
Walter D. Koenig ◽  
Philip N. Hooge ◽  
Mark T. Stanback ◽  
Joseph Haydock
Keyword(s):  
New Technologies ◽  
Field Methods ◽  
Long Term Study ◽  
Special Cases ◽  
Melanerpes Formicivorus ◽  
Dispersal Distances ◽  
Study Sites ◽  
Avian Populations ◽  
Near Future

Abstract Dispersal data are inevitably biased toward short-distance events, often highly so. We illustrate this problem using our long-term study of Acorn Woodpeckers (Melanerpes formicivorus) in central coastal California. Estimating the proportion of birds disappearing from the study area and correcting for detectability within the maximum observable distance are the first steps toward achieving a realistic estimate of dispersal distributions. Unfortunately, there is generally no objective way to determine the fates of birds not accounted for by these procedures, much less estimating the distances they may have moved. Estimated mean and root-mean-square dispersal distances range from 0.22–2.90 km for males and 0.53–9.57 km for females depending on what assumptions and corrections are made. Three field methods used to help correct for bias beyond the limits of normal study areas include surveying alternative study sites, expanding the study site (super study sites), and radio-tracking dispersers within a population. All of these methods have their limitations or can only be used in special cases. New technologies may help alleviate this problem in the near future. Until then, we urge caution in interpreting observed dispersal data from all but the most isolated of avian populations.

Nest cameras do not affect nest survival in a meadow-nesting shorebird

2020 ◽  
pp. 1-10
Author(s):  
VOLKER SALEWSKI ◽  
LUIS SCHMIDT
Keyword(s):  
Nest Survival ◽  
Bird Species ◽  
Conservation Strategies ◽  
Survival Models ◽  
Northern Germany ◽  
Term Study ◽  
Long Term Study ◽  
Limosa Limosa ◽  
Study Sites

Summary Identifying the fate of birds’ nests and the causes of breeding failure is often crucial for the development of conservation strategies for threatened species. However, collecting these data by repeatedly visiting nests might itself contribute to nest failure or bias. To solve this dilemma, automatic cameras have increasingly been used as a time-efficient means for nest monitoring. Here, we consider whether the use of cameras itself may influence hatching success of nests of the Black-tailed Godwit Limosa limosa at two long-term study sites in northern Germany. Annually between 2013 and 2019, cameras were used to monitor godwit nests. In 2014 and 2019, nests were randomly equipped with cameras or not, and nest survival checked independently of the cameras. Nest-survival models indicated that survival probabilities varied between years, sites and with time of the season, but were unaffected by the presence of cameras. Even though predation is the main cause of hatching failure in our study system, we conclude that predators did not learn to associate cameras with food either when the cameras were initially installed or after they had been used for several years. Cameras were thus an effective and non-deleterious tool to collect data for conservation in this case. As other bird species may react differently to cameras at their nests, and as other sets of predators may differ in their ability to associate cameras with food, the effect of cameras on breeding success should be carefully monitored when they are used in a new study system.

scholarly journals Big Benefits from Experimental Watersheds

Eos ◽  
2021 ◽  
Vol 102 ◽  
Author(s):  
Terri Cook
Keyword(s):  
Land Management ◽  
Agricultural Research ◽  
Conservation Practices ◽  
Term Study ◽  
Long Term Study ◽  
Global Land ◽  
Study Sites ◽  
Management And Conservation ◽  
Experimental Watersheds

Scientific insights from the Agricultural Research Service’s long-term study sites underpin dozens of models and research methods that guide global land management and conservation practices.

April: Six Degrees of Connectivity

2019 ◽  
Author(s):  
Ellen Wohl
Keyword(s):  
Green Algae ◽  
Term Study ◽  
Beaver Ponds ◽  
Side Channels ◽  
Long Term Study ◽  
Deep Shade ◽  
Northern Edge ◽  
Study Sites ◽  
Dark Green

By late April, the snow is gone from the beaver meadow. The promises of March are starting to be fulfilled: insects are on the wing, some of the willows have furry catkins along their branches, and fish jump from the quiet waters of the beaver ponds. I can no longer easily get around the beaver meadows on foot unless I wear chest waders. The sound of the beaver meadow in March was primarily wind. By April, the sound is primarily moving water. The water gurgles, shushes, and whispers. In another month it will roar with the melting snows. Another three miles up the creek valley and 1,500 feet higher, one of my long-term study sites still lies under 6 feet of snow, but in the meadow I see only one patch of tenacious snow-ice in the deep shade beneath a spruce along the northern edge of the meadow. I know that snow will still fall here during late spring storms, but it will melt quickly. March felt on the cusp, as if it could as easily tip toward winter or spring. Late April is definitely spring headed toward summer. The beaver meadow remains a riverscape more brown and tan than green. The willows are still leafless, although some of the branch tips are turning pale yellow-green and others seem to be taking on a more vivid orange hue. I can see the leaf buds starting to swell. The grass has just begun to grow in dark green tips steadily forcing their way through the thick mat of last year’s dead stems. Clusters of new leaves on low-growing wintergreen are the only other sign of green outside of the channels. Some of the smaller side channels are thick with emerald green algae undulating slowly in the current. A stonefly lands on my hand. Its slender, dark gray body seems surprisingly delicate for a creature that has hatched into the vagaries of April air, with its potential for blasting winds and sudden snow squalls.

Projected population consequences of climate change

2019 ◽  
pp. 147-164 ◽  
Author(s):  
David Iles ◽  
Stéphanie Jenouvrier
Keyword(s):  
Climate Models ◽  
Population Models ◽  
Climate Projections ◽  
Population Modelling ◽  
Population Forecasts ◽  
Long Term Study ◽  
Climate Forecasts ◽  
Key Points ◽  
Avian Populations

To anticipate the future state of avian populations in a changing climate, forecasts must rigorously account for uncertainty in future climate and population processes. This requires fusing IPCC-class climate projections with population models. In this chapter, we review the steps for developing climate-dependent population forecasts, while highlighting key biological considerations and methodological challenges. Throughout, we use examples from a long-term study of emperor penguins (Aptenodytes forsteri) to illustrate key points. We then conduct a literature review to compile a list of studies that have linked IPCC climate models with avian population models. At present, only a handful of studies have fused IPCC climate projections with avian population models, and generalities across systems thus remain elusive. Yet, the increasing availability and sophistication of climate models, coupled with new population modelling methods, hold promise for reducing forecast uncertainties and improving the relevance of population forecasts for policy.

scholarly journals Miniaturization of analytical systems

1998 ◽  
Vol 44 (9) ◽  
pp. 2008-2014 ◽  
Author(s):  
Larry J Kricka
Keyword(s):  
Self Assembly ◽  
New Technologies ◽  
Analytical Techniques ◽  
Sample Volume ◽  
Clinical Diagnostics ◽  
Key Issues ◽  
User Friendly ◽  
Near Future ◽  
Long Term Trend

Abstract Miniaturization has been a long-term trend in clinical diagnostics instrumentation. Now a range of new technologies, including micromachining and molecular self-assembly, are providing the means for further size reduction of analyzers to devices with micro- to nanometer dimensions and submicroliter volumes. Many analytical techniques (e.g., mass spectrometry and electrophoresis) have been successfully implemented on microchips made from silicon, glass, or plastic. The new impetus for miniaturization stems from the perceived benefits of faster, easier, less costly, and more convenient analyses and by the needs of the pharmaceutical industry for microscale, massively parallel drug discovery assays. Perfecting a user-friendly interface between a human and a microchip and determining the realistic lower limit for sample volume are key issues in the future implementation of these devices. Resolution of these issues will be important for the long-term success of microminiature analyzers; in the meantime, the scope, diversity, and rate of progress in the development of these devices promises products in the near future.

Influences of weather on Ixodes scapularis nymphal densities at long-term study sites in Connecticut

2015 ◽  
Vol 6 (3) ◽  
pp. 258-266 ◽  
Author(s):  
Laura E. Hayes ◽  
Jennifer A. Scott ◽  
Kirby C. Stafford
Keyword(s):  
Ixodes Scapularis ◽  
Term Study ◽  
Long Term Study ◽  
Study Sites

Fire and its impact on avian population dynamics

1997 ◽  
Vol 3 (3) ◽  
pp. 206 ◽  
Author(s):  
G. Barry Baker ◽  
E. Belinda Dettmann ◽  
Stephen J. Wilson
Keyword(s):  
Population Size ◽  
Fire Regimes ◽  
Long Term Study ◽  
Sclerophyll Forest ◽  
In Fire ◽  
Avian Populations ◽  
The Impact ◽  
Term Monitoring ◽  
Probability Of Capture

Survival rate, population size, recruitment and probability of capture, derived from a long-term study of 20 passerine species in wet sclerophyll forest near Canberra, were used to measure the impact of a high intensity wildfire which burnt 70% of the study area. The wildfire significantly affected the population size of 13 species for a period of up to six years following the fire. Survival and recruitment were the least sensitive measures of impact and indicated a significant response to fire for only 2 of 10 species. We detected measurable effects of the fire for 17 of the 20 species studied. Many of these species had returned to prefire levels within three years, but for nine species the effects were still apparent six years later. Mark-recapture methodology provides an effective way of measuring the impact of fire regimes in forest environments. Long-term monitoring programmes should be established in fire-prone forest environments to contribute toward our understanding of fire, and its effect on avian populations. Such programmes have resource implications and researchers are urged to encourage the participation of the amateur bird banding community to contribute to such projects.

scholarly journals Associations between malaria and MHC genes in a migratory songbird

2005 ◽  
Vol 272 (1571) ◽  
pp. 1511-1518 ◽  
Author(s):  
Helena Westerdahl ◽  
Jonas Waldenström ◽  
Bengt Hansson ◽  
Dennis Hasselquist ◽  
Torbjörn von Schantz ◽  
...  
Keyword(s):  
Positive Association ◽  
Malaria Parasites ◽  
Mhc Genes ◽  
Long Term Study ◽  
Histocompatibility Complex ◽  
Study Population ◽  
Migratory Songbird ◽  
Avian Populations ◽  
Mhc Alleles

Malaria parasites are a widespread and species-rich group infecting many wild populations of mammals, birds and reptiles. Studies on humans have demonstrated that genetic factors play a key role in the susceptibility and outcome of malaria infections. Until the present study, it has not been examined whether genetic variation in hosts is important for the outcome of malaria infections in natural avian populations. We investigated associations between major histocompatibility complex (MHC) genes and prevalence of three different avian malaria parasites ( Haemoproteus payevskyi (GRW1), Plasmodium sp. (GRW2) and Plasmodium sp. (GRW4)) in a long-term study of great reed warblers Acrocephalus arundinaceus . We hypothesized that the MHC genes could either give full protection against a malaria infection, or confer protection against lethal malaria and direct the infection towards being milder. We found a positive association between numbers of MHC class I alleles (a measure of level of heterozygosity) and prevalence of the GRW2 parasite, suggesting the latter scenario. There was also a positive association between a specific MHC allele (B4b), previously shown to be under frequency-dependent selection in the study population, and prevalence of GRW2. These associations suggest that individuals carrying either a large number of MHC alleles or a specific MHC allele are protected against lethal malaria infections.

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