scholarly journals SEASONAL INTERACTIONS, HABITAT QUALITY, AND POPULATION DYNAMICS IN MIGRATORY BIRDS

The Condor ◽  
2007 ◽  
Vol 109 (3) ◽  
pp. 535 ◽  
Author(s):  
D. RYAN NORRIS ◽  
PETER P. MARRA
Keyword(s):  
Population Dynamics ◽  
Habitat Quality ◽  
Migratory Birds ◽  
Seasonal Interactions

scholarly journals Seasonal Interactions, Habitat Quality, and Population Dynamics in Migratory Birds

The Condor ◽  
2007 ◽  
Vol 109 (3) ◽  
pp. 535-547 ◽  
Author(s):  
D. Ryan Norris ◽  
Peter P. Marra
Keyword(s):  
Population Dynamics ◽  
Habitat Selection ◽  
Habitat Quality ◽  
Migratory Birds ◽  
Population Level ◽  
Seasonal Interactions ◽  
Individual Level ◽  
Habitat Occupancy ◽  
Per Capita ◽  
The Individual

AbstractAbstract. Historically, studies of habitat selection have focused on quantifying how current patterns of habitat occupancy influence condition and survival within a season. This approach, however, is overly simplistic, especially for migratory birds that spend different periods of the year in geographically distinct places. Habitat occupancy and the resulting condition of individual birds is likely to be affected by events in the previous season, and the consequences of habitat occupancy will influence individuals and populations in subsequent seasons. Thus, for migratory birds, variation in habitat quality (and quantity) needs to be understood in the context of how events interact throughout periods of the annual cycle. Seasonal interactions can occur at the individual level or population level. Individual-level interactions occur when events in one season produce nonlethal, residual effects that carry over to influence individuals the following season. Population-level interactions occur when a change in population size in one season influences per capita rates the following season. We review various methods for estimating seasonal interactions and highlight a number of examples in the literature. Using a variety of techniques, including intrinsic and extrinsic markers, the vast majority of studies to date have measured seasonal interactions at the individual level. Obtaining estimates of density and changes in per capita rates across multiple seasons to determine population-level interactions has been more challenging. Both types of seasonal interactions can influence population dynamics, but predicting their effects requires detailed knowledge of how populations are geographically connected (i.e., migratory connectivity). We recommend that researchers studying habitat occupancy and habitat selection consider how events in previous seasons influence events within a season.

Long-term winter-site fidelity in Song Sparrows (Melospiza melodia)

The Auk ◽  
2019 ◽  
Vol 136 (2) ◽  
Author(s):  
Tosha R Kelly ◽  
Keith A Hobson ◽  
Garth W Casbourn ◽  
Elizabeth A MacDougall-Shackleton ◽  
Scott A MacDougall-Shackleton
Keyword(s):  
Population Dynamics ◽  
Site Fidelity ◽  
Migratory Birds ◽  
Melospiza Melodia ◽  
Factors Affecting ◽  
Song Sparrows ◽  
Breeding Grounds ◽  
Wintering Areas ◽  
Migratory Movements

Abstract In migratory animals, the degree to which individuals return to the same wintering sites across multiple years can affect fitness and population dynamics, and thus has important implications for conservation. Despite this, long-term evaluations of wintering-site fidelity are rare for migratory birds: many populations are intensively studied on their breeding grounds but tracking the migratory movements of small birds once they leave the breeding grounds is challenging. To evaluate patterns of overwintering location and fidelity, we collected winter-grown claw tissue from 301 Song Sparrows (Melospiza melodia; 449 samples) captured in spring at their breeding grounds over 6 consecutive yr and assessed stable hydrogen isotope (δ2Hc) values to determine within-individual repeatability and between-year variation in wintering latitudes. We also retrieved useable data from 8 geolocators over 2 consecutive winters. Geolocator-derived wintering positions correlated with origins based on δ2Hc values. Consistent with previous findings, male δ2Hc values reflected more northerly wintering areas than those of females, indicating shorter latitudinal migration distances for males, but the magnitude of the sex difference varied across years. The distribution of wintering latitudes was generally consistent among years, except for the 2015 舑2016 winter, which had unusually negative δ2Hc values. Values of δ2Hc were repeatable for males but not for females, suggesting that winter-site fidelity could differ between sexes. The data presented here emphasize the importance of tracking migratory populations across multiple years to uncover factors affecting population dynamics.

scholarly journals The demographic drivers of local population dynamics in two rare migratory birds

Oecologia ◽  
2011 ◽  
Vol 168 (1) ◽  
pp. 97-108 ◽  
Author(s):  
Michael Schaub ◽  
Thomas S. Reichlin ◽  
Fitsum Abadi ◽  
Marc Kéry ◽  
Lukas Jenni ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Migratory Birds ◽  
Local Population

scholarly journals Modeling population dynamics of solitary bees in relation to habitat quality

Web Ecology ◽  
2001 ◽  
Vol 2 (1) ◽  
pp. 57-64 ◽  
Author(s):  
K. Ulbrich ◽  
K. Seidelmann
Keyword(s):  
Population Dynamics ◽  
Sex Ratio ◽  
Population Size ◽  
Habitat Quality ◽  
Environmental Conditions ◽  
Extinction Risk ◽  
Maternal Investment ◽  
Solitary Bees ◽  
Population Development ◽  
Cell Construction

Abstract. To understand associations between habitat, individual behaviour, and population development of solitary bees we developed an individual-based model. This model is based on field observations of Osmia rufa (L) (Apoideae: Megachilidae) and describes population dynamics of solitary bees. Model rules are focused on maternal investment, in particular on the female’s individual decisions about sex and size of progeny. In the present paper, we address the effect of habitat quality on population size and sex ratio. We examine how food availability and the risk of parasitism influence long-term population development. It can be shown how population properties result from individual maternal investment which is described as a functional response to fluctuations of environmental conditions. We found that habitat quality can be expressed in terms of cell construction time. This interface factor influences the rate of open cell parasitism as the risk for a brood cell to be parasitized is positively correlated with the time of its construction. Under conditions of scarce food and under resulting long provision times even low parasitism rates lead to a high extinction risk of the population, whereas in rich habitats probabilities of extinction are low even for high rates of parasitism. For a given level of food and parasitism there is an optimum time for cell construction which minimizes the extinction risk of the population. Model results demonstrate that under fluctuating environmental conditions, decreasing habitat quality leads to a decrease in population size but also to rapid shifts in sex ratio.

scholarly journals Unravelling processes between phenotypic plasticity and population dynamics in migratory birds

2021 ◽  
Author(s):  
Jin Liu ◽  
Weipan Lei ◽  
Xunqiang Mo ◽  
Chris J. Hassell ◽  
Zhengwang Zhang ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Phenotypic Plasticity ◽  
Environmental Change ◽  
Annual Cycle ◽  
Census Data ◽  
Migratory Birds ◽  
Behavioural Plasticity ◽  
Life History Stage ◽  
Migration Strategy ◽  
Migrant Populations

AbstractPopulations can rapidly respond to environmental change via adaptive phenotypic plasticity, which can also modify interactions between individuals and their environment, affecting population dynamics. Bird migration is a highly plastic resource-tracking strategy in seasonal environments. Investigating the link between migration strategy plasticity and population dynamics can help to understand the regulation of migrant populations under environmental change. We first estimated population trends of migratory waterbirds in the face of the loss of staging habitat by using census data. We found increasing trends both in abundance and species richness in the remaining staging area, which we hypothesised was a consequence of behavioural plasticity generated by the loss of the historical suitable staging habitat. To test whether our hypothesis could explain observed trends, we constructed and analysed a full-annual-cycle individual-based model where each individual follows the same set of rules in the course of migration under a range of different staging habitat scenarios. Our empirical and theoretical results align well: the loss of staging habitat generates plasticity in migration strategies, with individuals remaining on the staging habitat for longer to obtain food due to a reduction in per capita food availability. The subsequent increasing population density on the staging habitat has knock on effects on population dynamics in the breeding and overwintering stage. Our results demonstrate how environmental change that impacts one energetically costly life history stage in migratory birds can have population dynamics impacts across the entire annual cycle via phenotypic plasticity.

scholarly journals Study On Spatio-Temporal Evolution of Habitat Quality Based On Land-Use Change In Chongming Dongtan, China

2021 ◽  
Author(s):  
Sheng Li ◽  
Bin Dong ◽  
Xiang Gao ◽  
Haifeng Xu ◽  
Chunqiu Ren ◽  
...  
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Habitat Quality ◽  
Migratory Birds ◽  
Habitat Degradation ◽  
Water Area ◽  
Ecological Environment ◽  
Cultivated Land ◽  
Construction Land ◽  
Invest Model

Abstract Chongming Dongtan is an important habitat for international migratory birds. It is of great significance to study its land use and habitat quality change for rare waterfowl protection and ecological environment restoration. Based on the land use data in 2002, 2012 and 2020, this paper analyzes the relationship between land use change and habitat quality evolution in Chongming Dongtan in recent 18 years by using InVEST model, land use dynamic degree and land use degree index. The results show that the main types of land use in the study area are water area and cultivated land, followed by woodland, reed beach, grass beach, bare beach and construction land. Among them, bare beach and construction land have changed dramatically, the former continuing to decrease while the latter continuing to increase. And the increasing speed began to slow down after 2012, and the increasing part was mainly from the surrounding cultivated land. Secondly, in terms of time change, the degradation of habitat quality in Chongming Dongtan has been gradually improved from aggravating trend in the past 18 years. In terms of spatial distribution, the habitat degradation degree of Chongming Dongtan is higher in the east and lower in the west, spreading from the center to the surrounding. Based on this, the change of land use and the interference of human activities are the important reasons for the change of ecological environment quality.

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