scholarly journals Harvest and Conservation of Sooty Shearwaters (Puffinus Griseus) in the Marlborough Sounds, New Zealand

2021 ◽  
Author(s):  
◽  
Amelia Frances Geary
Keyword(s):  
Carrying Capacity ◽  
Environmental Variability ◽  
Island Population ◽  
Population Modelling ◽  
Demographic Stochasticity ◽  
Extrinsic Factors ◽  
Ongoing Research ◽  
Island Populations ◽  
Population Sizes ◽  
Traditional Societies

<p>Customary harvest of wildlife can be an important mechanism through which indigenous people maintain a connection with their environment. Observations built up during harvesting events are also a useful way of monitoring change over time. However, not all traditional societies have lived harmoniously with their environment. Wildlife populations can become depleted quickly if not managed sustainably. Using traditional knowledge interviews, empirical data from two island populations and population modelling, I examined the viability of two island sooty shearwater populations in the Marlborough Sounds and their resilience to resumed, low-level harvest. The biology of the sooty shearwater populations was found to closely resemble that of populations found at higher latitudes. Historic harvest by Marlborough Maori probably had an important influence on the size of present day Marlborough populations. Viability models demonstrated that these populations were experiencing very low or negative intrinsic rates of increase. Population sizes have likely been affected by previous harvest and are not at carrying capacity. The populations are therefore vulnerable to demographic stochasticity, environmental variability and extrinsic factors such as fisheries bycatch. The low and negative growth rates for populations at small sizes not at carrying capacity are of concern where harvesting is proposed. This study provides a basis for ongoing research into the population trajectories of each island population. Harvesting is possible in one population provided an appropriate monitoring regime is established prior to harvest being undertaken, to ensure the long-term viability of Marlborough Sounds' sooty shearwater populations.</p>

scholarly journals Harvest and Conservation of Sooty Shearwaters (Puffinus Griseus) in the Marlborough Sounds, New Zealand

2021 ◽  
Author(s):  
◽  
Amelia Frances Geary
Keyword(s):  
Carrying Capacity ◽  
Environmental Variability ◽  
Island Population ◽  
Population Modelling ◽  
Demographic Stochasticity ◽  
Extrinsic Factors ◽  
Ongoing Research ◽  
Island Populations ◽  
Population Sizes ◽  
Traditional Societies

<p>Customary harvest of wildlife can be an important mechanism through which indigenous people maintain a connection with their environment. Observations built up during harvesting events are also a useful way of monitoring change over time. However, not all traditional societies have lived harmoniously with their environment. Wildlife populations can become depleted quickly if not managed sustainably. Using traditional knowledge interviews, empirical data from two island populations and population modelling, I examined the viability of two island sooty shearwater populations in the Marlborough Sounds and their resilience to resumed, low-level harvest. The biology of the sooty shearwater populations was found to closely resemble that of populations found at higher latitudes. Historic harvest by Marlborough Maori probably had an important influence on the size of present day Marlborough populations. Viability models demonstrated that these populations were experiencing very low or negative intrinsic rates of increase. Population sizes have likely been affected by previous harvest and are not at carrying capacity. The populations are therefore vulnerable to demographic stochasticity, environmental variability and extrinsic factors such as fisheries bycatch. The low and negative growth rates for populations at small sizes not at carrying capacity are of concern where harvesting is proposed. This study provides a basis for ongoing research into the population trajectories of each island population. Harvesting is possible in one population provided an appropriate monitoring regime is established prior to harvest being undertaken, to ensure the long-term viability of Marlborough Sounds' sooty shearwater populations.</p>

scholarly journals Identity by descent in island-mainland populations.

Genetics ◽  
1995 ◽  
Vol 139 (1) ◽  
pp. 429-437
Author(s):  
B Rannala ◽  
J A Hartigan
Keyword(s):  
Genetic Structure ◽  
Arrival Rate ◽  
Death Process ◽  
Process Time ◽  
Island Population ◽  
Gene Frequencies ◽  
Identity By Descent ◽  
Island Populations ◽  
Average Probability ◽  
Population Sizes

Abstract A new model is presented for the genetic structure among a collection of island populations, with fluctuating population sizes and continuous overlapping generations, using a stochastic birth, death and immigration (BDI) process. Immigrants enter each island from a large mainland population, with constant gene frequencies, according to a Poisson process. The average probability of identity by descent (IBD) for two haploid individuals randomly selected from an island population is f0 = (phi f1 + lambda)/(phi + lambda), where f1 is the probability of IBD for two randomly selected immigrants, lambda is the birth-rate for each individual, and phi is the arrival rate of immigrants into each island. The value of f0 is independent of the death process, time and N. The expected level of genetic differentiation among island populations is FST = (1 - 1/n)lambda/(phi + lambda), where n is the total number of islands receiving immigrants. Because f0 and FST are independent of the death process, for a BDI model, the population genetic structure for several general demographic situations may be examined using our equations. These include stochastic exponential, or logistic (regulated by death rate) growth within islands, or a "source-sink" population structure. Because the expected values of both f0 and FST are independent of time, these are achieved immediately, for a BDI model, with no need to assume the island populations are at genetic equilibrium.

scholarly journals Polygenic local adaptation in metapopulations: a stochastic eco-evolutionary model

2020 ◽  
Author(s):  
Enikő Szép ◽  
Himani Sachdeva ◽  
Nick Barton
Keyword(s):  
Population Size ◽  
Local Adaptation ◽  
Genetic Drift ◽  
Diffusion Approximation ◽  
Joint Distribution ◽  
Evolutionary Model ◽  
Ecological Niches ◽  
Demographic Stochasticity ◽  
Linkage Disequilibria ◽  
Population Sizes

AbstractThis paper analyses the conditions for local adaptation in a metapopulation with infinitely many islands under a model of hard selection, where population size depends on local fitness. Each island belongs to one of two distinct ecological niches or habitats. Fitness is influenced by an additive trait which is under habitat-dependent directional selection. Our analysis is based on the diffusion approximation and accounts for both genetic drift and demographic stochasticity. By neglecting linkage disequilibria, it yields the joint distribution of allele frequencies and population size on each island. We find that under hard selection, the conditions for local adaptation in a rare habitat are more restrictive for more polygenic traits: even moderate migration load per locus at very many loci is sufficient for population sizes to decline. This further reduces the efficacy of selection at individual loci due to increased drift and because smaller populations are more prone to swamping due to migration, causing a positive feedback between increasing maladaptation and declining population sizes. Our analysis also highlights the importance of demographic stochasticity, which exacerbates the decline in numbers of maladapted populations, leading to population collapse in the rare habitat at significantly lower migration than predicted by deterministic arguments.

scholarly journals Effects of climate change and environmental variability on the carrying capacity of Alaskan seabird populations

The Auk ◽  
2018 ◽  
Vol 135 (4) ◽  
pp. 975-991 ◽  
Author(s):  
Holly F. Goyert ◽  
Edward O. Garton ◽  
Aaron J. Poe
Keyword(s):  
Climate Change ◽  
Carrying Capacity ◽  
Environmental Variability

Confirmation of Aedes koreicus (Diptera: Culicidae) in Belgium and description of morphological differences between Korean and Belgian specimens validated by molecular identification

Zootaxa ◽  
2012 ◽  
Vol 3191 (1) ◽  
pp. 21 ◽  
Author(s):  
VEERLE VERSTEIRT ◽  
JAMES E. PECOR ◽  
DINA M. FONSECA ◽  
MARC COOSEMANS ◽  
WIM VAN BORTEL
Keyword(s):  
Korean Peninsula ◽  
Morphological Characteristics ◽  
Rapid Identification ◽  
Molecular Evidence ◽  
Island Population ◽  
Morphological Comparison ◽  
Aedes Koreicus ◽  
Island Populations ◽  
Molecular Comparison ◽  
Morphological Differences

In 2008, specimens resembling Aedes (Finlaya) koreicus (Edwards) (also Ochlerotatus koreicus or Hulecoeteomyia kore-ica) were found in Belgium during a national mosquito survey (MODIRISK). Small but consistent differences were, how-ever, observed between the specimens described from Peninsula Korea and those found in Belgian. To achieve the correctidentification a detailed morphological comparison was made between the Belgian specimens and reference material fromKorean mainland and island populations housed at the Smithsonian Institution (Walter Reed Biosystematics Unit (WR-BU), Washington, USA). The identification was furthermore supported by molecular evidence based on the ND4 region(mtDNA) of available Korean and Belgian mosquito specimens. Morphological and molecular comparison confirmed theinitial identification of Aedes koreicus. Based on morphological characteristics, the species collected in Belgium mostlikely originated from Jeju-do, an island south of the Korean Peninsula. The observed dissimilarities between Korean andBelgian specimens resembled a number of morphological differences mentioned previously between female adults col-lected on the Korean Peninsula and Jeju-do. This is the first report of Aedes koreicus outside its natural distribution range.A correct and rapid identification of new invading and spreading vector species is crucial for the implementation of effec-tive control measurements. Hence a correct and easy accessible description of all possible variations of species arrivingin new areas is highly recommended. Therefore, a comparative morphological study on the Smithsonian material of thespecies from Korean mainland, island population and from Belgium is given, pictures of the main aberrant characteristicsand scanning electron microscope images of all stages of the species are included and molecular confirmation of the identification based on the mtDNA ND4 region is provided.

Factors influencing population dynamics in island and mainland populations of the swamp antechinus (Antechinus minimus)

2008 ◽  
Vol 56 (3) ◽  
pp. 187 ◽  
Author(s):  
Michael G. Sale ◽  
Barbara A. Wilson ◽  
John P. Y. Arnould
Keyword(s):  
Island Population ◽  
Nutrient Inputs ◽  
Demographic Differences ◽  
Island Populations ◽  
Juvenile Recruitment ◽  
Factors Influencing ◽  
Eastern Australia ◽  
Demographic Processes ◽  
Island Habitats ◽  
Individual Body

Simultaneously analysing demographic processes of small mammals living in different ecological contexts may help to understand mechanisms that influence the growth and decline of these populations. The size and demography of swamp antechinus (Antechinus minimus) populations located in a coastal mainland habitat and on a small offshore island in south-eastern Australia were investigated. Large demographic differences occurred between the two ecosystems, with the island population density often 100 times greater than that on the mainland. The swamp antechinus in the mainland habitat was influenced by extrinsic climatic forces, with juvenile recruitment, individual body mass and overall population size being affected by rainfall, a factor likely to influence food availability for the species. However, the island population did not appear to be affected by drought to the same degree where allochthonous marine nutrient inputs may have offset any drought-induced reduction in primary production. Significantly greater juvenile recruitment in the island habitats combined with restricted emigration and potentially reduced predation and interspecific competition are likely to be responsible for the high population densities on the island. Although island populations appear robust, future conservation efforts should focus on mainland populations given the genetic deficiencies in the island populations.

Environmental Influences on the Development of Traditional Conservation in the South Pacific Region

1985 ◽  
Vol 12 (3) ◽  
pp. 217-230 ◽  
Author(s):  
Margaret D. Chapman
Keyword(s):  
Third World ◽  
Relative Equilibrium ◽  
Environmental Influences ◽  
South Pacific ◽  
Resource Depletion ◽  
The South ◽  
Island Populations ◽  
The Third ◽  
Traditional Societies ◽  
The Third World

There is an urgent need for improved understanding of conservation attitudes in the Third World because of the increasing rate of resource depletion that is now occurring in the countries involved. Although conservation practices by traditional societies in the Third World have received much attention from research workers, the fact that some practices are intentional and others inadvertent has been largely ignored. However, it is the motivation for these intentional conservation measures and the environmental influences on the people who apply them, which is crucial to understanding variations in conservation behaviour among traditional societies.Traditional conservation in the South Pacific was based on a complex system of resource-use taboos which prevented overexploitation in the limited island environment. These taboos contributed to the achievement during pre- European times of what appears from historical accounts to have been a state of relative equilibrium between island populations and their resources.Predictability and extremeness are two environmental factors which are thought to affect the development of conservational behaviour. Both these factors were examined in the light of traditional conservation in the South Pacific. Droughts and hurricanes are the two main sources of environmental unpredictability in the South Pacific, although the islands vary considerably in the degree to which they are affected by them. It was concluded that a distinction between real and perceived environmental predictability was necessary before one could fully understand the influence of predictability upon the development of conservational behaviour in the South Pacific.

Genetic diversity in natural and introduced island populations of koalas in Queensland

2012 ◽  
Vol 60 (5) ◽  
pp. 303 ◽  
Author(s):  
Kristen E. Lee ◽  
Jennifer M. Seddon ◽  
Stephen Johnston ◽  
Sean I. FitzGibbon ◽  
Frank Carrick ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Allelic Richness ◽  
Island Population ◽  
Founder Effects ◽  
Phascolarctos Cinereus ◽  
Island Populations ◽  
The North ◽  
Mitochondrial Haplotypes ◽  
Naturally Occurring ◽  
Microsatellite Alleles

Island populations of animals are expected to show reduced genetic variation and increased incidence of inbreeding because of founder effects and the susceptibility of small populations to the effects of genetic drift. Koalas (Phascolarctos cinereus) occur naturally in a patchy distribution across much of the eastern Australian mainland and on a small number of islands near the Australian coast. We compared the genetic diversity of the naturally occurring population of koalas on North Stradbroke Island in south-east Queensland with other island populations including the introduced group on St Bees Island in central Queensland. The population on St Bees Island shows higher diversity (allelic richness 4.1, He = 0.67) than the North Stradbroke Island population (allelic richness 3.2, He = 0.55). Koalas on Brampton, Newry and Rabbit Islands possessed microsatellite alleles that were not identified from St Bees Island koalas, indicating that it is most unlikely that these populations were established by a sole secondary introduction from St Bees Island. Mitochondrial haplotypes on the central Queensland islands were more similar to a haplotype found at Springsure in central Queensland and the inland clades in south-east Queensland, rather than the coastal clade in south-east Queensland.

scholarly journals The relative strength of selection on modifiers of genetic architecture under migration load

2021 ◽  
Author(s):  
Stephen R Proulx ◽  
Henrique Teotonio
Keyword(s):  
Local Adaptation ◽  
Genetic Architecture ◽  
Absolute Magnitude ◽  
Relative Strength ◽  
Demographic Stochasticity ◽  
Recombination Rates ◽  
Relative Population ◽  
Population Sizes ◽  
The Mean ◽  
Selection For

Gene flow between populations adapting to differing local environmental conditions creates a "migration load" because individuals might disperse to habitats where their survival is low or because they might reproduce with locally maladapted individuals. The amount by which the mean relative population fitness is kept below one creates an opportunity for modifiers of the genetic architecture to spread due to selection. Prior work that separately considered modifiers changing dispersal or recombination rates, or altering dominance or epistasis, has typically focused on the direction of selection rather than its absolute magnitude. We here develop methods to determine the strength of selection on modifiers of the genetic architecture, including modifiers of the dispersal rate, after populations evolved local adaptation. We consider scenarios with up to five loci contributing to local adaptation and derive a matrix model for the deterministic spread of modifiers. We find that selection for modifiers of epistasis and dominance is stronger than selection for decreased recombination, and that selection for partial reductions in recombination are extremely weak, regardless of the number of loci contributing to local adaptation. The spread of modifiers for a reduction in dispersal depends on the number of loci, pre-existing epistasis and extent of migration load. We identify a novel effect, that modifiers of dominance are more strongly selected when they are unlinked to the locus that they modify. Overall, these results help explain population differentiation and reproductive isolation and provide a benchmark to compare selection on genetic architecture modifiers in finite population sizes and under demographic stochasticity.

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