scholarly journals Studi Populasi Siamang (Simphalangus syndactylus) DI Hutan Lindung Register 25 Pematang Tanggang Kabupaten Tanggamus

2017 ◽  
Vol 5 (3) ◽  
pp. 66
Author(s):  
Nur Lutfiatuz Zahra ◽  
Gunardi Djoko Winarno
Keyword(s):  
Land Use ◽  
Sex Ratio ◽  
Government Regulation ◽  
Community Forest ◽  
Age Classes ◽  
Adult Age ◽  
Age Class ◽  
Adult Phase ◽  
The Individual ◽  
Individual Adult

Siamang (Simphalangus syndactylus Raffles, 1821) was the primates that protected by government regulation of Republic Indonesia number 7 in 1999. The existence of the siamang was important role in forest as pollinator and seed dispersers. Conversion land has increased into plantations and agriculture so that siamang population became descreased. Protected forest on Register 25 Pematang Tanggang Tanggamus Regency was bordered by community forest, thus vulnerable to land use that siamang population became descreased. The aimed of the research was to find the size of the group, the composition of age, the sexual ratio and the habitat of siamang in protected forest Register 25 Pematang Tanggang. The method used an area concentrated in 3 areal observation. Observations were 30 days effective. The results of this research showed that the Group of siamang found about 3 groups/7 individuals. The distribution of age classes in the individual adult phase of siamang about 6 individuals, adolescent phase about 1 individual and baby phase not found in this group. The sex ratio value in the adult age class phase was 1:1 and at adolescent age class phase was 1:0. According to siamang society does not interfere with human activities so that  not harm for them and their habitat was quite adequate for a population of siamang. Keywords: protected forest, population, siamang

scholarly journals Studi Kelompok Siamang (Hylobates Syndactylus) Di Repong Damar Pahmungan Pesisir Barat

2015 ◽  
Vol 3 (3) ◽  
pp. 85 ◽  
Author(s):  
Erna Maya Sari ◽  
Sugeng P. Harianto
Keyword(s):  
Sex Ratio ◽  
National Park ◽  
Local Community ◽  
Agroforestry Systems ◽  
Age Classes ◽  
Adult Age ◽  
Age Class ◽  
Hylobates Syndactylus ◽  
The Individual ◽  
Coastal District

Repong Damar in Pahmungan, West Coastal District is a buffer of Bukit Barisan Selatan National Park (TNBBS).  Repong Damar is one example of the success of agroforestry systems managed by local community that is still very traditional.  This area was identified as a component of siamang (Hylobates syndactylus) habitat.  The absence of data and the latest information about the siamang groups in Pekon Pahmungan were reasons of this research.  The purpose of this research was to determine the siamang groups in Repong Damar, used concentrated area methode.  The research was done on April 2015.  The results showed that the existence of siamang group in Repong Damar Pahmungan were 4 individuals/group.  The distribution of age classes in the individual phases of adult siamang were 2 individuals and the individual of adolescent phase were 2 individuals.  The sex ratio in the adult age class phase was 1:1 and at adolescent age class phase was 1:1.  Keywords: siamang, groups, repong damar

Aspects of the Demography of the Western Grey-Kangaroo, Macropus-Fuliginosus-Melanops, in Semiarid Northwest Victoria

1988 ◽  
Vol 15 (3) ◽  
pp. 257 ◽  
Author(s):  
GL Norbury ◽  
GM Coulson ◽  
BL Walters
Keyword(s):  
Sex Ratio ◽  
National Park ◽  
Adult Population ◽  
Severe Drought ◽  
Energy Costs ◽  
Age Classes ◽  
North West ◽  
Adult Age ◽  
Grey Kangaroo ◽  
Western Grey Kangaroo

The study was carried out at Hattah-Kulkyne National Park in semiarid north-west Victoria, during 3 years immediately following a severe drought. A sample of animals which died as a result of the drought (n= 196) and a shot sample (n=546) were examined to determine patterns of breeding, mortality and age structure. Births were concentrated in spring and summer, with a peak in November. Only 46% of mature females bred during the drought, whereas 100% bred two seasons later. The sex ratio of pouch young was not significantly different from parity, but showed a slight male-bias, however, the sex ratio of the adult population was markedly female-biased (1:3). Projected population growth was not realised in the years following the drought because of high mortality. There was evidence of male-biased mortality which was apparently accentuated during the drought. This biased mortality appeared similar in all adult age classes, and may have been a consequence of the disparate energy costs imposed by sex differences in body size and in mobility.

Comparative hunting abilities of polar bear cubs of different ages

1978 ◽  
Vol 56 (8) ◽  
pp. 1768-1772 ◽  
Author(s):  
Ian Stirling ◽  
Paul B. Latour
Keyword(s):  
Polar Bear ◽  
Canadian Arctic ◽  
Ursus Maritimus ◽  
Adult Males ◽  
Age Classes ◽  
Adult Age ◽  
Probability Of Survival ◽  
Age Class ◽  
Management Concept ◽  
Kill Rate

In most areas of the Canadian Arctic polar bear (Ursus maritimus) cubs apparently remain with their mothers until they are 2.5 years of age. The degree to which cubs of each age-class participate in the hunting of seals while with their mothers is examined in this paper in order to evaluate the degree to which they might be capable of independent hunting, should they be orphaned prior to the completion of the normal weaning period. Cubs of all age-classes did almost no hunting during the spring. The proportions of time spent hunting by yearling and 2-year-old cubs, and the durations of their lying 'still hunts' were not significantly different from each other but they were significantly shorter than their mothers' and than adult males' during the summer. However, the frequency of the lying 'still hunts' of 2-year-old cubs was double that of yearling cubs and the kill rate of 2-year-old cubs was comparable with that of adult age-classes, despite the fact they hunted for a significantly lesser proportion of their time. These results suggest that cubs which remain with their mothers until they are weaned have a higher probability of survival than those that do not and this interpretation lends support lo the management concept of total protection of family groups and the harvesting of independent bears only.

scholarly journals Towards a replicator dynamics model of age structured populations

2021 ◽  
Vol 82 (5) ◽  
Author(s):  
K. Argasinski ◽  
M. Broom
Keyword(s):  
Sex Ratio ◽  
Age Structure ◽  
Replicator Dynamics ◽  
Structured Populations ◽  
Reproductive Value ◽  
Leslie Matrix ◽  
Age Classes ◽  
Structured Population Model ◽  
Age Class ◽  
Age Structured

AbstractWe present a new modelling framework combining replicator dynamics, the standard model of frequency dependent selection, with an age-structured population model. The new framework allows for the modelling of populations consisting of competing strategies carried by individuals who change across their life cycle. Firstly the discretization of the McKendrick von Foerster model is derived. We show that the Euler–Lotka equation is satisfied when the new model reaches a steady state (i.e. stable frequencies between the age classes). This discretization consists of unit age classes where the timescale is chosen so that only a fraction of individuals play a single game round. This implies a linear dynamics and individuals not killed during the round are moved to the next age class; linearity means that the system is equivalent to a large Bernadelli–Lewis–Leslie matrix. Then we use the methodology of multipopulation games to derive two, mutually equivalent systems of equations. The first contains equations describing the evolution of the strategy frequencies in the whole population, completed by subsystems of equations describing the evolution of the age structure for each strategy. The second contains equations describing the changes of the general population’s age structure, completed with subsystems of equations describing the selection of the strategies within each age class. We then present the obtained system of replicator dynamics in the form of the mixed ODE-PDE system which is independent of the chosen timescale, and much simpler. The obtained results are illustrated by the example of the sex ratio model which shows that when different mortalities of the sexes are assumed, the sex ratio of 0.5 is obtained but that Fisher’s mechanism, driven by the reproductive value of the different sexes, is not in equilibrium.

scholarly journals Sex change in scallop Patinopecten yessoensis: response to population composition?

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5240
Author(s):  
Alla V. Silina
Keyword(s):  
Sex Ratio ◽  
Sex Change ◽  
Older Age ◽  
Age Classes ◽  
Patinopecten Yessoensis ◽  
Sex Structure ◽  
Age Class ◽  
Younger Age ◽  
In The Wild ◽  
Age Frequency Distribution

Sex structure is very labile between populations and specific for each population because it is a result of genetic, ontogenetic and biocenotic influences on the mollusks. In this study, the age frequency distribution, age-sex structure, and sex ratio were assessed in the wild populations of the Yeso scallop Patinopecten yessoensis (Jay) observed at fifteen sites in the northwestern Sea of Japan (=East Sea). The sex ratio varied between the populations from 0.83:1 to 1.52:1 (males/females), with the mean sex ratio being 1.03 ± 0.05:1. Within a population, the proportions of males and females in term of number differed between age classes. Males were more numerous than females in the younger age classes, and females prevailed over males in the older age classes. It was found that in different scallop populations the sex change occurred at different ages. In the populations that predominantly consisted of young (two- to four-year-old) individuals, males prevailed over females in the age class 2 yr.; the equal male/female proportion was found in the age class 3 yr.; and in older age classes, females prevailed over males. Another pattern was observed in the populations that consisted mainly of middle-aged (five- to six-year-old) individuals. Here, the age-sex ratio became equal at an age of 4–6 years. In the old populations (mainly 6–12-year-olds) the equal male/female proportion was observed at an age of 8–10 years. Thus, the age of sex change was not uniform for the scallop populations. It depended on the age structure of the population and, thus, was socially controlled. The greater number of females in the older age classes suggests a protandric sex change.

scholarly journals Prevalence of Batrachochytrium dendrobatidis in immature eastern hellbenders Cryptobranchus alleganiensis from North Carolina, USA

2020 ◽  
Vol 140 ◽  
pp. 73-78
Author(s):  
L Diaz ◽  
O Hernandez-Gomez ◽  
SD Unger ◽  
LA Williams ◽  
CM Bodinof Jachowski
Keyword(s):  
North Carolina ◽  
Batrachochytrium Dendrobatidis ◽  
Negative Effects ◽  
Age Classes ◽  
Field Surveys ◽  
Adult Age ◽  
Anthropogenic Stressors ◽  
Cryptobranchus Alleganiensis ◽  
Western North Carolina ◽  
The Individual

Batrachochytrium dendrobatidis (Bd) has been detected in wild hellbender Cryptobranchus alleganiensis populations, with rare instances of chytridiomycosis and Bd-induced mortality. To date, Bd surveillance in hellbender populations has been disproportionately focused on adult age classes. A lingering question is whether Bd might contribute to hellbender declines through disproportionate negative effects on immature age classes. The objective of this study was to quantify Bd prevalence and load in immature hellbenders in western North Carolina, USA. We conducted field surveys during 2018 and 2019 and collected 88 skin swabs from 84 hellbenders spanning 3 age classes. Bd was detected on 11% of individuals, including 8 larvae and 1 juvenile. We did not detect symptoms of chytridiomycosis or a decline in body condition in Bd-positive hellbenders. Load varied from approximately 1-153 zoospore equivalents for the 9 Bd-positive hellbenders and was not associated with size class of the individual. While hellbenders appeared to be abundant in each survey reach, more work is needed to determine whether Bd may increase the vulnerability of immature hellbenders to anthropogenic stressors.

Age-class influences on feeding choices of free-ranging wild boars (Sus scrofa)

1989 ◽  
Vol 67 (11) ◽  
pp. 2792-2796 ◽  
Author(s):  
Maryse Dardaillon
Keyword(s):  
Diet Composition ◽  
Dietary Diversity ◽  
Age Classes ◽  
Wild Boars ◽  
Adult Age ◽  
Plant Parts ◽  
Age Class ◽  
The Mean ◽  
Feeding Choices ◽  
Free Ranging

Diet composition and diversity were compared between juvenile, yearling, and adult wild boars living in the Camargue region (southern France). Despite close similarity, feeding choices differed in various respects. First, the mean stomach content included a greater proportion of animal matter in subadults (juveniles and yearlings combined) than in adults. Secondly, yearlings and adults ate larger proportions of rice, and larger quantities by weight of underground plant parts, than juveniles. These differences were attributed to differing nutritional requirements according to age-class. On the other hand, greater diversity of feeding choices was found in juveniles than within the yearling and adult age-classes. It is argued that early experience of a broad dietary diversity is an advantage for coping with fluctuations in food availability such as those encountered in the Camargue.

Population parameters of ringed seals (Phoca hispida Schreber, 1775) in the Svalbard area

1987 ◽  
Vol 65 (4) ◽  
pp. 1021-1027 ◽  
Author(s):  
Christian Lydersen ◽  
Ian Gjertz
Keyword(s):  
Sex Ratio ◽  
Ringed Seal ◽  
Adult Males ◽  
Population Parameters ◽  
Phoca Hispida ◽  
Age Class ◽  
Ringed Seals ◽  
Males And Females ◽  
The Mean ◽  
Sexually Mature

Samples were taken from 284 ringed seals (Phoca hispida) in the Svalbard area during April–July 1981 and March–April 1982. The age of 283 seals was determined by reading annuli in the cementum of the canine teeth. The mean age of the males was 11.3 years, and of the females, 14.9 years. Females were found to be significantly older than males. The mean length of sexually mature ringed seals was 128.9 cm for both sexes. The mean weight of adult males and females was 53.5 and 61.4 kg, respectively. Females were found to be significantly heavier than males. The sex ratio was 47.8% males and 52.2% females. Studies of microscopic sections of testis and epididymis from ringed seal males showed that 63, 75, and 80% of 5-, 6-, and 7-year-old animals, respectively, were sexually mature. The weights of testis and epididymis, diameters of tubuli, and the size of testis all showed a marked increase in the 5-year age-class. Macroscopic sections of ovaries from ringed seal females showed that 20, 60, and 80% of 3-, 4-, and 5-year-old animals, respectively, were sexually mature. The size of the ovaries showed a marked increase in the 5-year age-class. The ovulation rate of ringed seals from Svalbard was calculated to be 0.91.

scholarly journals Epiphytic lichens as indicator of land-use pattern and forest harvesting in a community forest in west Nepal

2012 ◽  
Vol 8 ◽  
pp. 24-32 ◽  
Author(s):  
Pramod Nag ◽  
Himanshu Rai ◽  
Dalip Kumar Upreti ◽  
Sanjeeva Nayaka ◽  
Rajan Kumar Gupta
Keyword(s):  
Land Use ◽  
Forest Harvesting ◽  
Conservation Strategy ◽  
Stand Age ◽  
Epiphytic Lichens ◽  
Community Forest ◽  
Land Use Pattern ◽  
Community Based ◽  
Lichen Diversity ◽  
Use Pattern

Human inhabitance and agriculture have fundamentally altered global pattern of biodiversity and ecosystem processes. Therefore, integration of community-based approach is an effective conservation strategy. Community forestry is an important community-based approach, which can help in conserving local ecological assets in a sustainable manner. Lichens are known to be more sensitive indicators of ecosystem functions and disturbances than any other cryptogam and vascular plant community. Present study reports a preliminary assessment of epiphytic lichens in a community forest in Dadeldhura district, west Nepal, in order to identify potential indicator of forest health and land-use pattern. Epiphytic (corticolous) lichens were sampled from ten land-use units (LUU), using narrow frequency grids of 10 cm × 50 cm, each divided into five sampling units of 10 cm × 10 cm, on the bark of selected tree species. Quercus leucotrichophora was the dominant phorophyte followed by Pinus roxburghii, Rhododendron arboreum and Myrica esculenta. Foliose parmeloid (Parmotrema spp., Heterodermia spp., Hypotrachyna spp., Bulbothrix spp., Canoparmelia spp., Canomaculina spp.) was the most abundant lichen group, found inhabiting all the phorophytes followed by crustose, fruticose and dimorphic growth forms. Maximum diversity of parmeloid lichens was recorded on older stand of Quercus while younger stands usually harbored crustose lichens (e.g., Lecanora spp., Basidia spp.). Though the lichen diversity increased from outer fringes of the forest to the core, the vegetation stand age was not distributed in any consistent pattern suggesting unconstrained harvesting of the forest. Lichen diversity was found constrained by phorophyte determinants (stand age, aspect, and bark properties) and community harvesting of the forest.doi: http://dx.doi.org/10.3126/botor.v8i0.5555 Botanica Orientalis – Journal of Plant Science (2011) 8: 24-32

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