scholarly journals On valuing patches: estimating contributions to metapopulation growth with reverse-time capture–recapture modelling

2011 ◽  
Vol 279 (1728) ◽  
pp. 480-488 ◽  
Author(s):  
Jamie S. Sanderlin ◽  
Peter M. Waser ◽  
James E. Hines ◽  
James D. Nichols
Keyword(s):  
Population Growth ◽  
Local Population ◽  
Peripheral Populations ◽  
Reverse Time ◽  
Genetic Population ◽  
Local Populations ◽  
Local Survival ◽  
Capture Recapture ◽  
Local Recruitment ◽  
Analytical Approaches

Metapopulation ecology has historically been rich in theory, yet analytical approaches for inferring demographic relationships among local populations have been few. We show how reverse-time multi-state capture–recapture models can be used to estimate the importance of local recruitment and interpopulation dispersal to metapopulation growth. We use ‘contribution metrics’ to infer demographic connectedness among eight local populations of banner-tailed kangaroo rats, to assess their demographic closure, and to investigate sources of variation in these contributions. Using a 7 year dataset, we show that: (i) local populations are relatively independent demographically, and contributions to local population growth via dispersal within the system decline with distance; (ii) growth contributions via local survival and recruitment are greater for adults than juveniles, while contributions involving dispersal are greater for juveniles; (iii) central populations rely more on local recruitment and survival than peripheral populations; (iv) contributions involving dispersal are not clearly related to overall metapopulation density; and (v) estimated contributions from outside the system are unexpectedly large. Our analytical framework can classify metapopulations on a continuum between demographic independence and panmixia, detect hidden population growth contributions, and make inference about other population linkage forms, including rescue effects and source–sink structures. Finally, we discuss differences between demographic and genetic population linkage patterns for our system.

scholarly journals Breeding transients in capture–recapture modeling and their consequences for local population dynamics

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Daniel Oro ◽  
Daniel F. Doak
Keyword(s):  
Growth Rate ◽  
Population Dynamics ◽  
Population Growth ◽  
Population Growth Rate ◽  
Local Population ◽  
Environmental Stochasticity ◽  
Adult Survival ◽  
Local Survival ◽  
First Reproduction ◽  
Capture Recapture

Abstract Standard procedures for capture–mark–recapture modelling (CMR) for the study of animal demography include running goodness-of-fit tests on a general starting model. A frequent reason for poor model fit is heterogeneity in local survival among individuals captured for the first time and those already captured or seen on previous occasions. This deviation is technically termed a transience effect. In specific cases, simple, uni-state CMR modeling showing transients may allow researchers to assess the role of these transients on population dynamics. Transient individuals nearly always have a lower local survival probability, which may appear for a number of reasons. In most cases, transients arise due to permanent dispersal, higher mortality, or a combination of both. In the case of higher mortality, transients may be symptomatic of a cost of first reproduction. A few studies working at large spatial scales actually show that transients more often correspond to survival costs of first reproduction rather than to permanent dispersal, bolstering the interpretation of transience as a measure of costs of reproduction, since initial detections are often associated with first breeding attempts. Regardless of their cause, the loss of transients from a local population should lower population growth rate. We review almost 1000 papers using CMR modeling and find that almost 40% of studies fitting the searching criteria (N = 115) detected transients. Nevertheless, few researchers have considered the ecological or evolutionary meaning of the transient phenomenon. Only three studies from the reviewed papers considered transients to be a cost of first reproduction. We also analyze a long-term individual monitoring dataset (1988–2012) on a long-lived bird to quantify transients, and we use a life table response experiment (LTRE) to measure the consequences of transients at a population level. As expected, population growth rate decreased when the environment became harsher while the proportion of transients increased. LTRE analysis showed that population growth can be substantially affected by changes in traits that are variable under environmental stochasticity and deterministic perturbations, such as recruitment, fecundity of experienced individuals, and transient probabilities. This occurred even though sensitivities and elasticities of these parameters were much lower than those for adult survival. The proportion of transients also increased with the strength of density-dependence. These results have implications for ecological and evolutionary studies and may stimulate other researchers to explore the ecological processes behind the occurrence of transients in capture–recapture studies. In population models, the inclusion of a specific state for transients may help to make more reliable predictions for endangered and harvested species.

scholarly journals Geographical Gradients of Genetic Diversity and Differentiation among the Southernmost Marginal Populations of Abies sachalinensis Revealed by EST-SSR Polymorphism

Forests ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 233 ◽  
Author(s):  
Keiko Kitamura ◽  
Kentaro Uchiyama ◽  
Saneyoshi Ueno ◽  
Wataru Ishizuka ◽  
Ikutaro Tsuyama ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Local Population ◽  
Distribution Center ◽  
Population History ◽  
Peripheral Populations ◽  
Abies Sachalinensis ◽  
Marginal Populations ◽  
Local Populations ◽  
Longitudinal Gradients

Research Highlights: We detected the longitudinal gradients of genetic diversity parameters, such as the number of alleles, effective number of alleles, heterozygosity, and inbreeding coefficient, and found that these might be attributable to climatic conditions, such as temperature and snow depth. Background and Objectives: Genetic diversity among local populations of a plant species at its distributional margin has long been of interest in ecological genetics. Populations at the distribution center grow well in favorable conditions, but those at the range margins are exposed to unfavorable environments, and the environmental conditions at establishment sites might reflect the genetic diversity of local populations. This is known as the central-marginal hypothesis in which marginal populations show lower genetic variation and higher differentiation than in central populations. In addition, genetic variation in a local population is influenced by phylogenetic constraints and the population history of selection under environmental constraints. In this study, we investigated this hypothesis in relation to Abies sachalinensis, a major conifer species in Hokkaido. Materials and Methods: A total of 1189 trees from 25 natural populations were analyzed using 19 EST-SSR loci. Results: The eastern populations, namely, those in the species distribution center, showed greater genetic diversity than did the western peripheral populations. Another important finding is that the southwestern marginal populations were genetically differentiated from the other populations. Conclusions: These differences might be due to genetic drift in the small and isolated populations at the range margin. Therefore, our results indicated that the central-marginal hypothesis held true for the southernmost A. sachalinensis populations in Hokkaido.

scholarly journals ESTIMATION OF CONTRIBUTIONS TO POPULATION GROWTH: A REVERSE-TIME CAPTURE–RECAPTURE APPROACH

Ecology ◽  
2000 ◽  
Vol 81 (12) ◽  
pp. 3362-3376 ◽  
Author(s):  
James D. Nichols ◽  
James E. Hines ◽  
Jean-Dominique Lebreton ◽  
Roger Pradel
Keyword(s):  
Population Growth ◽  
Reverse Time ◽  
Capture Recapture

The dynamics and conservation of a spatially subdivided avian population in a fragmented landscape

2002 ◽  
Vol 8 (3) ◽  
pp. 159 ◽  
Author(s):  
Gary W. Luck
Keyword(s):  
Population Growth ◽  
Growth Rates ◽  
Agricultural Landscape ◽  
Local Population ◽  
Bird Species ◽  
Fragmented Landscape ◽  
Population Growth Rates ◽  
Local Populations ◽  
Subdivided Population ◽  
Subdivided Populations

Many bird species have declined in abundance in the agricultural regions of southern Australia, The mechanisms underlying these declines and the viability of the remaining populations are largely unknown, A number of species exist as spatially subdivided populations in heavily fragmented landscapes. Metapopulation and source-sink theory have influenced thinking on the dynamics of subdivided populations, but the general applicability of these theories is uncertain. I examined the dynamics of a subdivided population of the Rufous Treecreeper Climacteris ruta, a declining woodland passerine, occupying a fragmented, agricultural landscape in southwestern Australia. I determined if local populations could replace themselves without immigration and estimated population growth rates for the periods 1998-1999 and 1999-2000. I also examined the influence of movement between local populations on the viability of the entire subdivided population. Out of four geographically defined local populations, only one was above replacement, and only in one year of the study. Fledgling productivity and recruitment in the remainder were not sufficient to compensate for breeding female mortality. Long-term population growth estimates were <1 for all local populations, but variability in demographic rates suggested that the status of these populations may fluctuate over time. Also, there appeared to be sufficient movement between local populations, and into the study area from nearby habitat remnants, to slow or halt any decline in local population size, Within- and between-local-population processes appeared to be important to the viability of the treecreeper population during the two years of the study, and this is consistent with the general principles of metapopulation theory. I compared the dynamics of the treecreeper population occupying the fragmented landscape with one occupying a continuously wooded landscape and found that the latter had population growth rates >1, suggesting it may be an important population source and vital to the regional viability of the species.

scholarly journals Estimation of Contributions to Population Growth: A Reverse-Time Capture-Recapture Approach

Ecology ◽  
2000 ◽  
Vol 81 (12) ◽  
pp. 3362 ◽  
Author(s):  
James D. Nichols ◽  
James E. Hines ◽  
Jean-Dominique Lebreton ◽  
Roger Pradel
Keyword(s):  
Population Growth ◽  
Reverse Time ◽  
Capture Recapture

scholarly journals Survival during the pre-fledging period rather than during post-fledging drives variation in local recruitment of an endangered migratory shorebird, the Southern Dunlin Calidris alpina schinzii

2020 ◽  
Author(s):  
Veli-Matti Pakanen ◽  
Robin Hagstedt ◽  
Angela Pauliny ◽  
Donald Blomqvist
Keyword(s):  
Annual Variation ◽  
Local Population ◽  
Chick Survival ◽  
Breeding Sites ◽  
Calidris Alpina ◽  
Brood Survival ◽  
Annual Range ◽  
Capture Recapture ◽  
Study Population ◽  
Local Recruitment

Abstract The declines in wet-grassland breeding shorebird populations are considered to mainly result from changes in reproduction. While there is plenty of information on nest survival, little reliable information exists on local recruitment due to confounding effects of permanent emigration. Furthermore, few studies have been able to study the roles of pre- and post-fledging survival on local recruitment. Therefore, it is unclear whether local recruitment of young reflects conditions at the breeding sites or at non-breeding sites. We studied an isolated population of the endangered Southern Dunlin (Calidris alpina schinzii) breeding on the west coast of Sweden to examine (1) brood survival (probability of at least one chick fledging) by following broods fates and (2) local recruitment (survival from hatching to 1 year old) using capture-recapture data. We then examined how much of the annual variation in juvenile survival was explained by variation in brood survival. Brood survival was on average 0.58 (annual range 0.08–1.00) and explained 64% of variation in annual local recruitment. Still local recruitment was rather high for a shorebird (0.17, SE = 0.023), which reflects the isolated nature of the study population. Our results suggest that local recruitment seems to be mainly constrained by chick survival during the pre-fledging period. Therefore, management of breeding sites leading to increased brood survival, e.g., reducing predation on chicks, should have strong impacts on local recruitment and local population growth.

Aspects of the Relationships between the Community of Sheikh Abd al-Qurna and Ancient Egyptian Monuments

2020 ◽  
pp. 507-522
Author(s):  
Andrew Bednarski ◽  
Gemma Tully
Keyword(s):  
Social Action ◽  
Single Case ◽  
Local Population ◽  
Social Awareness ◽  
Single Case Study ◽  
Local Populations ◽  
Ancient Egyptian ◽  
Complex Relationships

Epigraphers and archaeologists working in Egypt must navigate a host of complex relationships both on and off site. This chapter explores the multifaceted nature of local Egyptian peoples’ relationships with nearby monuments through the lens of a single case study: the site of Sheikh Abd al-Qurna and its local population, the Qurnawi. Egyptologists have not traditionally sought to incorporate formally the stories and histories of local populations in their studies of pharaonic sites. An increasing blend of social awareness and the desire for social action on the part of both foreign professionals and local activists, however, is pushing Egyptologists to re-evaluate their practices, which, in turn, is moving the discipline in new and positive directions.

Survival and recruitment in the population ecology of the endangered Bombina pachypus (Amphibia: Anura)

2018 ◽  
Vol 39 (3) ◽  
pp. 265-274
Author(s):  
Claudio Angelini ◽  
Andrea Tiberi ◽  
Bruno Cari ◽  
Filippo Giachi
Keyword(s):  
Population Dynamics ◽  
Population Growth ◽  
Breeding Site ◽  
Juvenile Dispersal ◽  
Relative Contribution ◽  
Annual Population ◽  
Conservation Concern ◽  
Local Recruitment ◽  
Effective Conservation ◽  
High Recruitment

Abstract Global amphibian decline is a subject of great conservation concern, yet often basic demographic information is absent, which prevents the understanding of population trends and the planning of effective conservation management. We analysed capture-mark-recapture data from six populations of the endangered Bombina pachypus in order to understand the relative contribution of survival and recruitment to population growth, and to assess if any differences exist among populations in terms of their population dynamics. We found that survival was rather high and generally constant among sites, and recruitment was low, with the exception of two single years at one site. Population growth depended on survival on all sites, except the years following high recruitment at one site. Annual population size was generally lower than 30 individuals, but in one site it was estimated to be larger than 50. Our findings suggest that juvenile survival is more important for population dynamics than recruitment from the larval to the juvenile stage. We also suggest that the low recruitment rates we recorded was a result of juvenile dispersal, and that when populations exhibited high recruitment it was due to occasional successful migration or local recruitment. This pattern could represent a way to counterbalance the risk of inbreeding in populations composed of few individuals, a common characteristic of populations of B. pachypus. Finally, we suggest that conservation measures for B. pachypus should be planned at the landscape scale, and should not be limited solely to the breeding site and its close surroundings.

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