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.

scholarly journals ASSESSMENT OF THE DEMOGRAPHIC SITUATION OF UKRAINE: NATURAL MOVEMENT AND POPULATION REPRODUCTION

2020 ◽  
Author(s):  
Hanna Svydlo ◽  
◽  
Iryna Sierova ◽  
Keyword(s):  
Mortality Rate ◽  
Social Studies ◽  
Birth Rate ◽  
The State ◽  
National Academy Of Sciences ◽  
Demographic Situation ◽  
Factors Influencing ◽  
Natural Movement ◽  
Demographic Processes ◽  
Academy Of Sciences

Due to the difficult socio-economic situation and worsening of demographic situation, including the consequences of hostilities and ongoing occupation of the part of Ukraine, today the importance of population study and the research on the factors influencing its changes is increasing. During the study of demographic processes on the basis of a thorough analysis, strategic decisions relevant to the use and reproduction of the country's labour potential, stimulation of the birth rate, reduction of mortality, increase of natural population growth, prevention of depopulation processes, providing effective employment and improvement of social protection of the people are made. The demographic factor is one of the determinants for ensuring sustainable and safe development of the country, and the issue of demographic development should be considered as a factor and at the same time as a result of the functioning of the state. The main purpose of the study is to identify trends in the changes of the main indicators characterizing demographic processes in the country. Methodologically and informationally, this paper is based on the scientific works, the materials from reccurent publications and Internet, the laws and regula-tions and the data of the State Statistics Service of Ukraine and Ptoukha Institute for Demography and Social Studies of the National Academy of Sciences of Ukraine. The methods used in the study are structural and dynamic analysis, comparison and generalization of the data collected by the State Statistics Service of Ukraine and Ptoukha Institute for Demography and Social Studies of the National Academy of Sciences of Ukraine. During a study of a phenomenon or a process, first of all, the categorical apparatus is determined. Based on the purpose of the study, the concept of reproduction and natural movement of the population is defined and their theoretical description is given. This paper considers the reproduction of the population as the historically and socio-economically conditioned process of constant and continuous renewal of hu-man generations. Since the natural movement of the population is a process analysis of the birth and death of people, this paper considers such types of population reproduction as archetype, traditional type, transitional type and modern type. For the analysis of the natural movement of the population as a component of demographic safety, the following indicators were evaluated: average life expectancy at birth; depopulation rate; the overall mortality rate of the country's population; in-fant mortality (child mortality up to the age of 1); total birth rate; net reproduction rate; marriage rate; divorce rate. The findings of the analysis show that the main rea-son of the worsening of demographic situation is decrease in the birth rate and in-crease in the mortality rate. Currently, the birth rate in Ukraine is largely limited by both economic factors (insufficient wages, shortage of jobs) and social factors (changes in reproductive habits and norms expressed in the popularity of single-parent families). The analysis revealed socio-economic factors influencing the demo-graphic situation in Ukraine.

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.

Nitrogen balances in temperate perennial grass and clover dairy pastures in south-eastern Australia

2007 ◽  
Vol 58 (12) ◽  
pp. 1167 ◽  
Author(s):  
R. J. Eckard ◽  
D. F. Chapman ◽  
R. E. White
Keyword(s):  
Ammonium Nitrate ◽  
Management Practices ◽  
Perennial Grass ◽  
Dairy Farms ◽  
Nutrient Inputs ◽  
N Losses ◽  
Total N ◽  
South Eastern ◽  
Eastern Australia ◽  
South Eastern Australia

Nitrogen (N) fertiliser use on dairy pastures in south-eastern Australia has increased exponentially over the past 15 years. Concurrently, imports of supplementary feed onto dairy farms have increased, adding further nutrients to the system. These trends raise questions about the environmental effects of higher nutrient inputs to dairy farms. To gauge possible effects, annual N balances were calculated from an experiment where N inputs and losses were measured for 3 years from non-irrigated grass/clover pastures receiving either no N fertiliser (Control) or 200 kg N/ha applied annually as ammonium nitrate or urea. Estimated total N inputs, averaged over the 3 years, were 154, 314, and 321 kg N/ha.year for the control, ammonium nitrate, and urea treatments, respectively, while N outputs in meat and milk were 75, 99, and 103 kg N/ha.year, respectively. The corresponding calculated N surplus was 79, 215, and 218 kg N/ha.year for the 3 treatments, respectively, and the ratio of product N/total-N inputs for the 3 treatments ranged from 50% in the control to 32% for both N treatments. Total N losses averaged 56, 102, and 119 kg N/ha.year, leaving a positive N balance of 23, 112, and 99 kg N/ha.year for the control, ammonium nitrate, and urea treatments, respectively. The ratio of product N/total-N inputs or the N surplus may be useful in monitoring the efficiency of conversion of N into animal products and the potential environmental effect at a whole-farm scale. However, additional decision support or modelling tools are required to provide information on specific N losses for a given set of conditions and management inputs. Given the large range in N losses there is opportunity for improving N-use efficiency in dairy pastures through a range of management practices and more tactical use of grain and N fertiliser.

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 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>

Modelling the factors influencing Sambar Deer (Rusa unicolor) occurrence in the wet eucalypt forests of south-eastern Australia

2020 ◽  
Author(s):  
S. Sotorra ◽  
D. Blair ◽  
W. Blanchard ◽  
D. Lindenmayer
Keyword(s):  
National Parks ◽  
Negative Binomial ◽  
Negative Binomial Regression ◽  
South Eastern ◽  
Factors Influencing ◽  
Eastern Australia ◽  
Mountain Ash ◽  
Sambar Deer ◽  
Central Highlands ◽  
South Eastern Australia

Many invasive species have had negative effects on the Australian environment, including the introduced Sambar Deer (Rusa unicolor). However, there is a paucity of information on the factors influencing the fine scale distribution and abundance patterns of Sambar Deer in south-eastern Australia. We present the results of a field survey of Sambar Deer in the Critically Endangered Mountain Ash ( Eucalyptus regnans) forests of the Central Highlands, Victoria. Our key question was: What factors influence detections of Sambar deer (based on scat counts) within the Mountain Ash forests of the Victorian Central Highlands? We surveyed 86 long-term field sites and detected a total of 245 groups of Sambar Deer pellets on 42% of these sites. Negative binomial regression modelling identified three factors associated with the occurrence of deer pellets. We recorded more pellets: (1) in 30 and 80 year old forest that remained unburned in fires that occurred in 2009, (2) on sites within closed National Parks relative to sites in State Forest, and (3) close to streams.

Meiofauna associated with mangroves in the Hunter River estuary and Fullerton Cove, south-eastern Australia

1985 ◽  
Vol 36 (1) ◽  
pp. 41 ◽  
Author(s):  
M Hodda ◽  
WL Nicholas
Keyword(s):  
Relative Abundance ◽  
River Estuary ◽  
Species Distributions ◽  
Total Density ◽  
Nematode Density ◽  
South Eastern ◽  
Algal Food ◽  
Factors Influencing ◽  
Eastern Australia ◽  
South Eastern Australia

The meiofauna from 14 sampling sites around the Hunter River estuary is described, and the factors influencing total density and relative abundance of nematodes and copepods and some species distributions are discussed. Elevation above low tide mark influenced nematode density, and salinity influenced copepod density and relative abundance. Both nematodes and copepods were most dense near the mud surface, and algal food and the depth of the reducing layer appear to be partially responsible for major differences in the density of these two taxa at different sites. Pollution also influenced the total density of both nematodes and copepods and also the relative abundance of oligochaetes: these relationships are discussed in the light of other, contradictory, reports.

Implications for the conservation of genetic diversity in mohair goats from a comparison of a relic island population with breeds farmed in Australia

1999 ◽  
Vol 39 (4) ◽  
pp. 411 ◽  
Author(s):  
T. G. Balasingham ◽  
N. A. Robinson ◽  
B. A. McGregor
Keyword(s):  
South Africa ◽  
Genetic Diversity ◽  
Genetic Improvement ◽  
Genetic Relationships ◽  
Genetic Material ◽  
Island Population ◽  
Island Populations ◽  
Angora Goats ◽  
Semi Arid ◽  
Nei's Genetic Distance

The genetic relationships between an abandoned population of mohair-style, fibre-producing goats from the remote semi-arid Faure Island, Western Australia and 3 modern breeds of Angora goats (Australian, southern African and Texan) were investigated. Faure Island goats originated from stock introduced in the 1890s, reputedly from South Africa. Farmed Faure goats were abandoned on the island about 1918, but their fine mohair fleece has since generated commercial interest within the Australian mohair industry. Nineteen microsatellite loci were used to compare Nei’s genetic distance between and variation within the breeds. Faure Island goats are more similar to southern African and Texan Angoras than to Australian Angoras. Genetic variability was lower in Australian Angoras than in Faure Island, southern African and Texan Angoras (lowest proportion of polymorphic loci, mean heterozygosity and mean number of alleles). Current Faure Island mohair-style goats are more closely related to modern southern African Angora goats than to traditional Australian Angora goats, while the reduced variability in the latter may have resulted from inbreeding. These results have implications for the genetic improvement of fibre-producing goats and for the conservation of genetic material from island populations of goats.

scholarly journals Rapid mortality transition of Pacific Islands in the 19th century

2016 ◽  
Vol 145 (1) ◽  
pp. 1-11 ◽  
Author(s):  
B. S. PENMAN ◽  
S. GUPTA ◽  
G. D. SHANKS
Keyword(s):  
Infectious Disease ◽  
Pacific Islands ◽  
Herd Immunity ◽  
Case Fatality ◽  
Mass Mortality ◽  
Darwinian Evolution ◽  
Island Population ◽  
Pacific Island ◽  
Island Populations ◽  
Disease Mortality

SUMMARYThe depopulation of Pacific islands during the 16th to 19th centuries is a striking example of historical mass mortality due to infectious disease. Pacific Island populations have not been subject to such cataclysmic infectious disease mortality since. Here we explore the processes which could have given rise to this shift in infectious disease mortality patterns. We show, using mathematical models, that the population dynamics exhibited by Pacific Island populations are unlikely to be the result of Darwinian evolution. We propose that extreme mortality during first-contact epidemics is a function of epidemiological isolation, not a lack of previous selection. If, as pathogens become established in populations, extreme mortality is rapidly suppressed by herd immunity, Pacific Island population mortality patterns can be explained with no need to invoke genetic change. We discuss the mechanisms by which this could occur, including (i) a link between the proportion of the population transmitting infectious agents and case-fatality rates, and (ii) the course of infection with pathogens such as measles and smallpox being more severe in adults than in children. Overall, we consider the present-day risk of mass mortality from newly emerging infectious diseases is unlikely to be greater on Pacific islands than in other geographical areas.

scholarly journals Insularity induces changes on body and mandible morphology in a Mediterranean population of the greater white-toothed shrew Crocidura russula (Hermann, 1780)

2018 ◽  
Vol 87 (4) ◽  
pp. 275-286
Author(s):  
Alejandro Sánchez-Chardi ◽  
Marian García-Pando ◽  
Eudald Pujol-Buxó ◽  
Maria A. Sans-Fuentes ◽  
María José López-Fuster ◽  
...  
Keyword(s):  
Interspecific Competition ◽  
Body Condition ◽  
Intraspecific Competition ◽  
Direct Result ◽  
Island Population ◽  
Mediterranean Population ◽  
Island Populations ◽  
Terrestrial Mammals ◽  
Crocidura Russula ◽  
Mandible Shape

Island populations of terrestrial mammals often undergo extensive behavioural and morphological changes when separated from mainland populations. Within small mammals these changes have been mainly reported in rodents but were poorly assessed in soricomorphs. In this study we compared mandible morphology and body condition between mainland and island populations of the greater white-toothed shrew, Crocidura russula. The results indicated that island specimens were bigger and heavier than the mainland counterpart, and they showed changes in mandible shape that were associated with higher mechanical potentials. We suggest that these changes might be the result of the interaction of two main factors taking place in the island population: ecological release (i.e. the decrease of predation and interspecific competition), and consequently the increase of intraspecific competition. While the increase in size and body condition in island shrews could be a direct result from reduced predation and interspecific competition, the changes in mandible shape and the increase of both mechanical potential and sexual dimorphism could have arisen indirectly as a response to stronger intraspecific competition.

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