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

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

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.

scholarly journals Notes on age determination, growth and measurements of Brown Hyaenas Hyaena Brunnea from the Kalahari Gemsbok National Park

Koedoe ◽  
1982 ◽  
Vol 25 (1) ◽  
Author(s):  
M.G.L Mills
Keyword(s):  
National Park ◽  
Age Determination ◽  
Tooth Eruption ◽  
Distribution Range ◽  
The Other ◽  
Body Measurements ◽  
Age Classes ◽  
Full Size ◽  
Adult Age ◽  
Different Parts

Brown hyaenas were aged on the basis of tooth eruption and wear and five age-classes were recognised. Weights and seven different body measurements were recorded from 38 immobilised hyaenas. Full size is reached at the age of 30 months, but age-class 5 animals were significantly lighter than were animals from the other adult age-classes. This was probably due to the worn down premolars of old animals resulting in less efficient bone chewing. With a few puzzling exceptions the sizes of brown hyaenas from different parts of their distribution range are similar.

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.

Oestrous Behaviour and Female Choice in the African Elephant

Behaviour ◽  
1983 ◽  
Vol 86 (3-4) ◽  
pp. 167-195 ◽  
Author(s):  
Cynthia J. Moss
Keyword(s):  
Female Choice ◽  
National Park ◽  
Size Class ◽  
African Elephants ◽  
Age Classes ◽  
Short Term ◽  
Individual Level ◽  
Female Behaviour ◽  
The Individual

Abstract1. During the course of an eight year field study of African elephants in Amboseli National Park, Kenya, from September, 1972 to December, 1980, females were seen exhibiting oestrous behaviour on 154 occasions, during which 43 copulations were witnessed. 2. Five categories of oestrous behaviour are described: a) wariness, b) the oestrous walk, c) the chase, d) mounting, and e) consort behaviour. 3. The oestrous behaviour as described was found to be temporally associated with ovulation, as judged by conceptions, in 70.7% of 58 cases. 4. The duration of oestrous periods is estimated at 2-6 days. 5. On average Amboseli females conceived once every 5 years and for each of these conceptions the female may only have been in oestrus once. 6. Evidence from the Amboseli study suggests that some females may exercise choice in mating partners. For example, females were able to elude their pursuers in 69.4% of all chases (n = 134). Observation of female behaviour during oestrus suggested that some females preferred to mate with males in the largest size class, particularly those in musth. 7. Two possible short-term advantages to females exercising choice in mating partners are suggested: a) avoidance of harassment from other bulls; and b) Large males in musth may be more likely to impregnate a female. 8. A possible long-term advantage to mating with a Large, and therefore older, male could be his ability to pass on a trait for longevity. 9. Although females may be exercising choice among the size/age classes, male-male competition among the Large males may override female choice on the individual level.

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 PENDUGAAN PARAMETER DEMOGRAFI DAN PREFERENSI HABITAT TANGKASI (Tarsius lariang) DI KAWASAN TAMAN NASIONAL LORE LINDU

2019 ◽  
Vol 9 (1) ◽  
pp. 144-151
Author(s):  
Abdul Rosyid
Keyword(s):  
National Park ◽  
Forest Cover ◽  
Total Population ◽  
Secondary Forest ◽  
Research Area ◽  
Distribution Area ◽  
Cultivated Plants ◽  
Age Classes ◽  
Adult Age ◽  
Preferred Habitat

Tarsius lariang, also called tangkasi is one of the endemic animals which is found in Lore Lindu National Park (LLNP). The threat to the tarsius population are the limitation of the distribution area, the escalation of forests exploitation, and hunting. People around the forest tend to think the tangkasi as a pest which eats cultivated plants. Therefore, population and habitat research is important. The purpose of this study is to estimate the demographic parameters and identify the characteristics of the habitat of the tangkasi, so that it can be known that the habitat component is important for the existence of the tangkasi in LLNP. The results of this study indicate the density of individual tangkasi across the LLNP region is 95.55 individuals per km². Individual density on Primary Dryland Forest Cover (PDFC) was 80.21 individuals per km² and in Dryland Secondary Forest (DSF) cover was 218.29 individuals per km², which still in normal level. The population density of tangkasi groups in the LLNP area is 35 groups per km², for the PDFC 32 and for the DSF of 54 groups per km². The total population of tangkasi based on age structure located in the research area of LLNP, PDFC, and DSF shows that the age of the juvenile is very low compared to the sub-adult age classes. It shows that tangkasi population is decreasing (regressive population). The preferred habitat of the tangkasi is the type of Dryland Secondary Forest (SDF) with a very steep slope of < 45% and altitude between 1301 and 1800 m asl.

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.

scholarly journals Occurrence of disease symptoms and selected biotic factors connected with beech (Fagus sylvatica L.) dieback phenomenon in stands of The Magurski National Park

2012 ◽  
Vol 58 (2) ◽  
pp. 441-452
Author(s):  
Piotr Rojek
Keyword(s):  
Fagus Sylvatica ◽  
National Park ◽  
Forest Site ◽  
Age Classes ◽  
Similar Frequency ◽  
Disease Symptoms ◽  
Age Class ◽  
Leaf Chlorosis ◽  
Cryptococcus Fagisuga ◽  
Crown Thinning

The studies were carried out in 12 beech stands, growing on mountain fresh forest site in Magurski National Park. Stands differed in respect of exposition (northern and southern) and age - lower age classes (21-60 years old) and higher age classes (81-120 years old). This paper presents evaluation of frequency of disease symptoms occurrence in the crowns and on the trunks of beeches. The presence and the place of occurrence of fungus <i>Ascodichaena rugosa</i> and insects <i>Cryptococcus fagisuga</i> and <i>Ectoedemia liebwerdella</i>, which could be connected with beech bark necrosis on the trunks were noted down. In each stand 50 trees, growing side by side in center of the stand, were analyzed. Among 600 analyzed trees of <i>Fagus sylvatica</i>, 2.6% had a dead top. Crown thinning were present on 51.8% of trees. It appeared frequently in higher age class stands and didn't cover more than ¼ of the crown. Moreover, in crowns of 4.1% of trees the leaf chlorosis appeared. The most frequent symptom on trunks of beeches were local necroses (98% of trees), that were sometimes connected with slime fluxing (3.3%). Necroses were the most number in stands growing on the southern exposition and on south parts of the trunks. <i>Cryptococcus fagisuga</i> appeared mostly in high age class stands. Intensity of its appearance was similar on the trees growing on the southern and northern exposition (respectively, 48.3% and 53.3%). Particular parts of the trunks were colonized with similar frequency by <i>C. fagisuga</i> irrespective of cardinal points (N-29.3%; S-21.7%; W-22.7%; E-26.2%) and number of necroses on the trunks. <i>Ascodichaena rugosa</i> appeared on 8.6% of trees, more frequently on their north parts of the trunks (7.3%). In the places colonized by fungi <i>A. rugosa</i>, insect <i>C. fagisuga</i> was absent. Occurrence of larvae of <i>Ectoedemia liebwerdella</i> was mostly found on trunks of beeches growing on the southern exposition (43.0%), on 35.3% of trees they colonized south parts of trunks. There wasn't observed any connection between the occurrence of these larvae and symptoms of local necroses.

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