Regional and local effects drive changes in spawning stream occupancy in a sockeye salmon metapopulation

Author(s):  
Michael J Bradford ◽  
Douglas C. Braun

There is a need to explicitly consider metapopulation dynamics in the development of conservation strategies for spatially-structured populations. We examined the spatial dynamics of sockeye salmon (Oncorhynchus nerka) that spawn in 36 streams of the Stuart River watershed in British Columbia, Canada, using a 69-year record of spawner abundance and a demographically-based Bayesian dynamic occupancy model. We identified a set of 12 streams with good habitat conditions that were occupied >90% of years despite large year-to-year changes in abundance. Over 85% of spawners were concentrated in these streams. Many other streams with poorer habitat had small populations that were not persistent over time and were periodically recolonized by dispersers from other streams. Although it is often assumed population diversity and resiliency is maximized when all available habitats are used, for this salmon metapopulation, resiliency is due to the core streams of higher habitat quality. Currently other streams make only small contributions to population abundance, however, some may have conservation value if their habitats become more suitable for spawning in the future.

Author(s):  
Richard D. Weir ◽  
Trevor A. Kinley ◽  
Richard W. Klafki ◽  
Clayton D. Apps

This chapter is based on ecological information on 82 radio-tagged badgers (39 F, 43 M) among three study populations in British Columbia, Canada between 1996 and 2010, data that were collected to learn more about the ecology of badgers and consider how variation in their ecology might inform regional conservation strategies. The widely spaced, lower density prey and distribution of soil deposits suitable for digging in British Columbia likely required badgers to use substantially larger areas, relative to the core range, in which to acquire sufficient energy to survive and reproduce. Strikes from automobiles were the primary cause of death among all radio-tagged badgers and this source of mortality is pervasive throughout the limited distribution of badgers in British Columbia. Despite their potential for high fecundity, populations of badgers in British Columbia likely remain at considerable risk compared to those in the core of the species’ range.


2018 ◽  
Vol 12 (2) ◽  
pp. e0006234 ◽  
Author(s):  
Jorge Velázquez-Castro ◽  
Andrés Anzo-Hernández ◽  
Beatriz Bonilla-Capilla ◽  
Moisés Soto-Bajo ◽  
Andrés Fraguela-Collar

Author(s):  
Anna Clara Balbina Silva ◽  
Afonso Pelli

Compreender os mecanismos que regulam a dinâmica das populações espacialmente estruturadas é um desafio crítico para os ecólogos e gestores de conservação. A dinâmica de populações é um ramo da ecologia que estuda as populações como sistema em atividades, relacionando as influências ambientais com a distribuição e abundância dos indivíduos e suas interações com o ambiente. O presente artigo é uma revisão bibliográfica, com o objetivo de identificar produções científicas relevantes sobre dinâmica populacional. Para isso, foram utilizados periódicos revisados por pares, na base de Periódicos Capes. A pesquisa foi realizada em junho de 2019, utilizando-se as palavras-chave para título contendo: "population dynamics" e no assunto “ecology”, a partir de 2014, quando o texto completo estava disponível. Foram considerados como critérios de exclusão os artigos publicados antes de 2014. Após a leitura dos títulos dos artigos, foram selecionados 34 artigos que foram lidos na íntegra. Em livros disponíveis no acervo da biblioteca da Universidade Federal do Triângulo Mineiro, foram selecionados quatro livros no tema dinâmica populacional. O referencial teórico aborda os aspectos da dinâmica de populações, tabela de vida, formas de crescimento e interações populacionais. Ressalta-se a necessidade de novos estudos que ainda possuem lacunas, que venha complementar e contribuir para o conhecimento de organismos que faltam ou ainda não possuem registros de estudos. Palavras-chave: Taxas de Natalidade e Mortalidade. Atributos Populacionais. Dispersão. AbstractUnderstanding the mechanisms that regulate the dynamics of spatially structured populations is a critical challenge for ecologists and conservation managers. Population dynamics is a branch of ecology that studies populations as a system in activities, relating environmental influences to the individuals’ distribution and abundance and their interactions with the environment. This article is a bibliographic review, aiming to identify relevant scientific productions about population dynamics. Thus. peer-reviewed journals were used in the Capes Periodicals base, the research was conducted in June 2019, using the keywords for title containing "population dynamics" and in the subject "ecology", from 2014, when the full text was available. Exclusion criteria were: articles published before 2014, after reading the article titles, 34 articles were selected that met the initially proposed criteria and were read in full. In books available in the library collection of the Federal University of Triângulo Mineiro, with a search for the dynamic population theme, 4 books were used. The theoretical framework addresses the aspects of population dynamics, life table, forms of growth and population interactions. It is emphasized  the need for further studies that still have gaps, which will complement and contribute to the knowledge of organisms that are missing or do not have study records. Keywords: Birth and Mortality Rates. Population Attributes. Dispersion.


2020 ◽  
pp. 105-124
Author(s):  
Michael J. Fogarty ◽  
Jeremy S. Collie

Aquatic populations are patchily distributed. The full implications of this statement for the dynamics of these populations depend very strongly on movement and dispersal patterns. The characteristically heterogeneous distribution of exploited aquatic species is of course essential to harvesting strategies employed by fishers. It can also present important challenges to management when species distributions contract to core habitat areas and these concentrations can be readily located and exploited. The types of models described in this chapter, including metapopulation models, provide an initial framework for considering the dynamics of spatially structured populations. Dispersal can provide a stabilizing force by providing a subsidy or rescue effect for depleted populations. Realistic representation of spatial processes in models of aquatic populations is an evolving art. Quantifying movement and connectivity of aquatic species entails special challenges. Spatially explicit models should account for exchange among subpopulations in relation to their size, distance, and degree of separation.


2014 ◽  
Vol 272 ◽  
pp. 198-207 ◽  
Author(s):  
Charles L. Nunn ◽  
Peter H. Thrall ◽  
Peter M. Kappeler

2007 ◽  
Vol 85 (10) ◽  
pp. 1031-1048 ◽  
Author(s):  
D.A. Driscoll

Where habitat loss and fragmentation is severe, many native species are likely to have reduced levels of dispersal between remnant populations. For those species to avoid regional extinction in fragmented landscapes, they must undergo some kind of metapopulation dynamics so that local extinctions are countered by recolonisation. The importance of spatial dynamics for regional survival means that research into metapopulation dynamics is essential. In this review I explore the approaches taken to examine metapopulation dynamics, highlight the analytical methods used to get the most information out of field data, and discover some of the major research gaps. Statistical models, including Hanski’s incidence function model (IFM) are frequently applied to presence–absence data, an approach that is often strengthened using long-term data sets that document extinctions and colonisations. Recent developments are making the IFM more biologically realistic and expanding the range of situations for which the model is relevant. Although accurate predictions using the IFM seem unlikely, it may be useful for ranking management decisions. A key weakness of presence–absence modelling is that the mechanisms underlying spatial dynamics remain inferential, so combining modelling approaches with detailed demographic research is warranted. For species where very large data sets cannot be obtained to facilitate statistical modelling, a demographic approach alone or with stochastic modelling may be the only viable research angle to take. Dispersal is a central process in metapopulation dynamics. Research combining mark–recapture or telemetry methods with model-selection procedures demonstrate that dispersal is frequently oversimplified in conceptual and statistical metapopulation models. Dispersal models like the island model that underlies classic metapopulation theory do not approximate the behaviour of real species in fragmented landscapes. Nevertheless, it remains uncertain if additional biological realism will improve predictions of statistical metapopulation models. Genetic methods can give better estimates of dispersal than direct methods and take less effort, so they should be routinely explored alongside direct ecological methods. Recent development of metacommunity theory (communities connected by dispersal) emphasises a range of mechanisms that complement metapopulation theory. Taking both theories into account will enhance interpretation of field data. The extent of metapopulation dynamics in human modified landscapes remains uncertain, but we have a powerful array of field and analytical approaches for reducing this knowledge gap. The most informative way forward requires that many species are studied in the same fragmented landscape by applying a selection of approaches that reveal complementary aspects of spatial dynamics.


2011 ◽  
Vol 7 (4) ◽  
pp. 578-580 ◽  
Author(s):  
Tom Vogwill ◽  
Andy Fenton ◽  
Michael A. Brockhurst

High dispersal rates between patches in spatially structured populations can impede diversification and homogenize diversity. These homogenizing effects of dispersal are likely to be enhanced by coevolving parasites that impose strong selection on hosts for resistance. However, the interactive effects of dispersal and parasites on host diversification have never been tested. We used spatially structured, experimental populations of the bacterium Pseudomonas fluorescens , cultured with or without the phage SBW25Ф2 under three levels of dispersal (none, localized or global), and quantified diversity in terms of evolved bacterial colony morphologies after approximately 100 bacterial generations. We demonstrate that higher levels of colony morphology richness evolved in the presence of phage, and that dispersal reduced diversity most strongly in the presence of phage. Thus, our results suggest that, while parasites can drive host diversification, host populations coevolving with parasites are more prone to homogenization through dispersal.


Oryx ◽  
2017 ◽  
Vol 53 (1) ◽  
pp. 165-173 ◽  
Author(s):  
Priscila Maria Pereira ◽  
João Valsecchi ◽  
Helder Queiroz

AbstractIn many regions primates are an important dietary resource for isolated human populations, and they are among the most hunted species by traditional and indigenous communities in the Neotropics. Little is known about the characteristics or the spatial and temporal patterns of hunting, which limits a more detailed evaluation of its impact. We describe, quantify and analyse the spatial dynamics of primate hunting in the várzea (seasonally flooded forest) and paleovárzea (characterized by a series of low-lying ridges interspersed with flooded depressions, which result from cyclical depositional processes) environments of Central Amazonia, based on the monitoring of riverine communities at the Amanã and Mamirauá Sustainable Development Reserves over an 11-year period. During this time 402 primate hunting events were recorded, involving the harvesting of 541 individuals of nine species: Alouatta juara, Aotus cf. vociferans, Ateles chamek, Cacajao ouakary, Callicebus lucifer, Cebus albifrons, Saguinus inustus, Saimiri cassiquiarensis and Sapajus macrocephalus. Two hundred and forty of these hunts occurred in the paleovárzea and 162 in the várzea. The distances travelled by the hunters from their communities to the kill sites were significantly different between the environments, with longer distances being covered in the paleovárzea. Hunters in the paleovárzea also hunted across significantly larger areas than those in the várzea. The continuous monitoring of hunting areas and the gathering of data on the exploitation of species are necessary to understand the effects of hunting, as well as to support decision making in the management of the local fauna by traditional communities, and the development of effective conservation strategies for the local game species.


2005 ◽  
Vol 233 (2) ◽  
pp. 177-189 ◽  
Author(s):  
Cailin Xu ◽  
Mark S. Boyce ◽  
Madhav Gadgil ◽  
Vidyanand Nanjundiah

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