scholarly journals Movements and home ranges of radio-tracked Crocodylus porosus in the Cambridge Gulf region of Western Australia

2004 ◽  
Vol 31 (5) ◽  
pp. 495 ◽  
Author(s):  
Winston R. Kay
Keyword(s):  
Habitat Preferences ◽  
Dry Season ◽  
Home Ranges ◽  
Juvenile Male ◽  
Wet Season ◽  
Gulf Region ◽  
Main River ◽  
Main River Channel ◽  
Crocodylus Porosus ◽  
Riverine Habitats

VHF radio-tags were attached to 16 estuarine crocodiles that were tracked between October 2001 and May 2003. Male (n = 12) and female (n = 4) crocodiles exhibited distinctly different patterns of movement. Females occupied a small core linear range (1.3 ± 0.9 km) on the main river channel during the dry season and moved up to 62 km to nesting habitat during the wet season, returning to the same core area the following dry season. They occasionally made excursions away from their core areas during the dry season. Males moved considerable distances along the Ord River throughout the year. The largest range recorded was 87 km for a 2.5-m juvenile male. However, ranges of males did not appear to be related to body size, with the largest two ranges being recorded for the smallest (2.5 m) and largest (4.3 m) males tagged. Rates of movement of males did not differ significantly between three size classes of males but there were significant seasonal differences, with the highest mean rates of movement occurring during the summer wet season (4.0 ± 5.4 km day–1). However, males were quite mobile during the dry season and the highest rate of movement detected was 23.3 km day–1 for a 4.3-m male at the end of July. The highest rate of sustained movement was 9.8 km day–1 for a translocated 2.6-m juvenile male, which travelled 118 km in 12 days to return to the area of its capture. Neither males nor females showed exclusive habitat preferences for any of four broad riverine habitats identified on the Ord River. However, the three largest males had activity centres that they returned to frequently despite numerous excursions throughout the year, both up- and downriver. Males had substantial range overlaps with no obvious spatial partitioning, suggesting that territoriality is not an important behavioural characteristic of free-ranging male crocodiles along the Ord River.

Home range and movements of radio-tracked estuarine crocodiles (Crocodylus porosus) within a non-tidal waterhole

2008 ◽  
Vol 35 (2) ◽  
pp. 140 ◽  
Author(s):  
Matthew L. Brien ◽  
Mark A. Read ◽  
Hamish I. McCallum ◽  
Gordon C. Grigg
Keyword(s):  
Home Range ◽  
National Park ◽  
Dry Season ◽  
River Channel ◽  
Home Ranges ◽  
Adult Males ◽  
Wet Season ◽  
Crocodylus Porosus ◽  
Range Overlap ◽  
Large Adult

We radio-tracked five male and eight female estuarine crocodiles (Crocodylus porosus) in a non-tidal waterhole in Lakefield National Park in northern Queensland during the late dry/mid-wet season (2003–04) and the following dry season (2004). Individual crocodiles occupied larger home ranges (River Channel Areas (RCA) during the late dry/mid-wet season (10.64 ± 2.86 ha) than in the dry season (3.20 ± 1.02 ha), and males occupied larger home ranges (23.89 ± 2.36 ha) than females (5.94 ± 1.34 ha) during the late dry/mid-wet season. There were no obvious differences in home range between sexes during the dry season. During the late dry/mid-wet season, adult males often travelled long distances along the waterhole while females moved less. During the dry season, movement patterns were quite variable, with no clear difference between sexes. All crocodiles were most active from late afternoon (1500–1800 hours) until midnight. Individual home ranges (RCA) overlapped considerably during the late dry/mid-wet season. The extent of home-range overlap between three adult males and the number of times they either passed each other or were located near each other was particularly striking. Previous research has come to conflicting conclusions about the extent of territoriality in wild estuarine crocodiles, although it has been widely believed that males are highly territorial. The findings imply that large adult male estuarine crocodiles are not highly territorial in non-tidal freshwater systems that are geographically confined.

scholarly journals Agricultural crops in the diet of bearded capuchin monkeys, Cebus libidinosus Spix (Primates: Cebidae), in forest fragments in southeast Brazil

2008 ◽  
Vol 25 (1) ◽  
pp. 32-39 ◽  
Author(s):  
Carlos Henrique de Freitas ◽  
Eleonore Z. F. Setz ◽  
Alba R. B. Araújo ◽  
Nivar Gobbi
Keyword(s):  
Fruit Production ◽  
Dry Season ◽  
Southeastern Brazil ◽  
Capuchin Monkeys ◽  
Home Ranges ◽  
Forest Fragments ◽  
Wet Season ◽  
Plant Matter ◽  
Wide Range ◽  
Cebus Libidinosus

Capuchin monkeys occupy a wide range of habitats where they feed on fruits, arthropods, and vertebrates. Their large home ranges (80-900 ha) suggest that living in forest fragments may challenge their adaptability. We identified and quantified the main food items of Cebus libidinosus Spix, 1823 in forests fragments (100 ha) in southeastern Brazil. We recorded the feeding activities of two groups using scan sampling over a 13-month period. The diet was composed of fruits, crops, animal prey, seeds, plant matter and undetermined. Fruit was eaten more in the wet season than in the dry season, and maize and sugar cane consumption peaked in the early dry season. The proportion of fruit in the diet was positively correlated with fruiting intensity of zoochorous trees. The plant diet included 54 species, with maize, Rhamnidium elaeocarpus, Acrocomia aculeata, Guazuma ulmifolia and Cariniana, being most important. Although dietary composition and diversity were similar to capuchins in larger forest fragments, feeding on crops attained higher percentages at times when zoochorous fruit production was low in fragments.

scholarly journals Trophic ecology of two piranha species, Pygocentrus nattereri and Serrasalmus marginatus (Characiformes, Characidae), in the floodplain of the Negro River, Pantanal

2014 ◽  
Vol 26 (4) ◽  
pp. 381-391 ◽  
Author(s):  
Fabiane Silva Ferreira ◽  
Wagner Vicentin ◽  
Fábio Edir dos Santos Costa ◽  
Yzel Rondon Súarez
Keyword(s):  
Trophic Ecology ◽  
Niche Breadth ◽  
Feeding Activity ◽  
Interspecific Variation ◽  
Dry Season ◽  
Ontogenetic Changes ◽  
Flood Season ◽  
Negro River ◽  
Main River ◽  
Main River Channel

AIM: This study aimed to evaluate influence of hydrological variation, ontogeny and interspecific variation in the feeding activity and diet composition for P. nattereri and S. marginatus in floodplain of Negro River, South Pantanal. METHODS: The samples were taken with the use of gillnets and cast nets of different sizes, from October/2005 to August/2008. RESULTS: We sampled 748 specimens, 442 of P. nattereri and 306 of S. marginatus. We identified 31 items in the dry and 14 in the flood season for P. nattereri, and 29 items in the dry and eight in the flood season for S. marginatus. For both species, fish was the predominant food item in both seasons. The PERMANOVA results showed that the diet varied significantly between the two species (p<0.001), during ontogenetic development (p<0.001) and seasonally (p=0.024). The ancova results suggests that the intensity of food intake was higher in the dry season (p<0.001) for both species. The niche breadth varied only between studied species with S. marginatus presenting higher niche breadth than P. nattereri. CONCLUSION: Piranhas feed more during dry season, probably because in this period food is more varied and abundant, due to the concentration of fish in the main river channel. There were ontogenetic changes in the diet, with no feeding overlap between the two species, probably because of differences in preference for some items and differences in feeding behavior displayed during hunting attacks.

Home-range and den use of the mahogany glider, Petaurus gracilis

2000 ◽  
Vol 27 (1) ◽  
pp. 49 ◽  
Author(s):  
Stephen M. Jackson
Keyword(s):  
Home Range ◽  
Dry Season ◽  
Home Ranges ◽  
Adjacent Area ◽  
Wet Season ◽  
Male And Female ◽  
Fragmented Habitat ◽  
Significant Difference ◽  
Socially Monogamous ◽  
Males And Females

The home-range of the mahogany glider was estimated, and its social behaviour examined, by following radio-collared animals over a two-year period within an area of continuous habitat and an adjacent area of fragmented habitat. The average home range within the continuous habitat was 19.25 ha for males and 20.34 ha for females, with male and female pairs occupying a combined area of 23.15 ha. In contrast, the average home range in the fragmented habitat was 11.05 ha for males and 6.80 ha for females, with a combined home-range of male and female pairs being 11.60 ha. The average overlap of the home ranges of paired males and females was 85.9%, compared with approximately 11% for non-paired individuals, which suggests that mahogany gliders are socially monogamous. For a total of 46 nights on which gliders were considered to behave normally for the entire night, the average foraging distance was 1506 m (range 590–3420 m) with no significant difference between males and females in either the continuous or fragmented habitat. There was, however, a significant difference in the distance individuals travelled during different times of the year, with longer distances being travelled during late dry season/wet season and shorter distances during the early to mid dry season. Mahogany gliders also travelled further when there was a high availability of nectar and pollen than when there was lower availability. A total of 83 dens (tree hollows) were recorded for the mahogany glider, with the poplar gum, Eucalyptus platyphylla, forest red gum, Eucalyptus tereticornis, and Clarkson's bloodwood, Corymbia clarksoniana, being most used.

scholarly journals Seasonal abundance and breeding habitat occupancy of the Orinoco Goose (Neochen jubata) in western Brazilian Amazonia

2014 ◽  
Vol 24 (4) ◽  
pp. 518-529 ◽  
Author(s):  
WHALDENER ENDO ◽  
TORBJØRN HAUGAASEN ◽  
CARLOS A. PERES
Keyword(s):  
Sandy Beaches ◽  
Dry Season ◽  
River Channel ◽  
Habitat Associations ◽  
Breeding Habitat ◽  
Seasonal Abundance ◽  
Encounter Rate ◽  
Brazilian Amazonia ◽  
Main River ◽  
Main River Channel

SummaryThe Near-threatened Orinoco Goose Neochen jubata is a poorly known South American sheldgoose with a declining population and range distribution. In this study, we surveyed the Orinoco Goose population along the middle reaches of the Rio Juruá, western Brazilian Amazonia, and its first-order tributaries. We quantified the seasonal abundance of geese, pinpointed their approximate breeding season, and examined their habitat associations and the potential effects of human activities on their abundance. Hunting by local villagers was also monitored to assess the offtake rate of this species. Orinoco Goose occurrence in the region was highly seasonal and restricted to the dry season. We estimated a mean dry-season encounter rate of 7.18 ± 2.45 adult individuals per 4-km section along this river. Immature individuals were seen along the river margins from August to December. The species showed a strong preference for sandy beaches and was primarily restricted to the main river channel, with few individuals occurring along tributaries. The encounter rate of this species was also significantly related to fluvial distance from the municipal urban centre and to the level of protection from hunting. Hunting of Orinoco Goose was reported in 12 of the 26 villages monitored. The seasonal appearance of the Orinoco Goose in the region indicates that this is a migratory population. Our study indicates that strict protection of the river margins, and sandy beaches in particular, along the main river channel is likely to be positive for the conservation of this species along the Rio Juruá. However, further knowledge of migration routes is critical for effective protection of both breeding and non-breeding populations.

Seasonal changes in home-range area and habitat use by the agile wallaby (Macropus agilis)

2003 ◽  
Vol 30 (6) ◽  
pp. 593 ◽  
Author(s):  
Simon C. Stirrat
Keyword(s):  
Home Range ◽  
Habitat Use ◽  
Home Range Size ◽  
Food Resources ◽  
Dry Season ◽  
Range Size ◽  
Home Ranges ◽  
Wet Season ◽  
Short Supply ◽  
Male And Female

Radio-tagged male and female agile wallabies were tracked in the wet and dry seasons at a site in Darwin, Northern Territory, and home ranges estimated using a kernel-based estimator. Home-range size (95% contour) was larger in the dry season, when food quality was poorer, and males had larger home ranges than females. Core range size (55% contour) did not differ between seasons or sexes. Average male and female home-range sizes in the wet season were 16.6 ha and 11.3 ha respectively. Wet-season core range sizes were 4.8 ha and 3.2 ha respectively. Average male and female home-range sizes in the dry season were 24.6 ha and 15.3 ha respectively, and dry-season core range sizes were 5.1 ha and 4.0 ha respectively. Home-range size for both sexes varied in the two seasons; the smallest and largest female home ranges were 6.3 ha and 24.0 ha respectively, while male home-range size varied from 7.6 ha to 38.2 ha. Seasonal differences in home-range size can be attributed to expansion of night-time foraging areas in the dry season when good-quality food resources were in short supply. Habitat use also differed between seasons. In the dry season more fixes were located in forest areas, particularly in the evening, when wallabies foraged in forest areas for alternate food resources including browse, leaf litter, flowers and fruits of rainforest tree and shrub species. In the wet season, wallabies emerged from day-time resting areas earlier in the afternoon and therefore more wallabies were located in open areas grazing on high-quality herbage in the evening.

Litter production and accumulation in stressed mangrove communities in the Embley River estuary, north-eastern Gulf of Carpentaria, Australia

1996 ◽  
Vol 47 (5) ◽  
pp. 737 ◽  
Author(s):  
CA Conacher ◽  
C O'Brien ◽  
JL Horrocks ◽  
RK Kenyon
Keyword(s):  
River Estuary ◽  
Canopy Cover ◽  
River Channel ◽  
Litter Production ◽  
Wet Season ◽  
Main River ◽  
Main River Channel ◽  
Temporary Habitats ◽  
North Eastern ◽  
Mangrove Communities

From March 1993 to March 1994, the three main mangrove communities in the Embley River Estuary (12�37'S, 141�52'E) were studied: Rhizophora forest in the main river channel and in a small creek, and Ceriops forest and Avicennia forest in a small creek. In November 1993, all A. marina trees in the main river channel lost their leaves, and some understorey species in Avicennia forests in tributaries died; this is attributed to environmental stress. This defoliation and death continued for at least a year. The Rhizophora forests were moderately to highly productive of litter, were the tallest, and had the greatest canopy cover and the greatest surface area of ground structures or potential refugia for juvenile finfish and crustaceans; all the litter was quickly transported by the tides to other parts of the estuary. The Ceriops and Avicennia forests produced less litter and were probably under water stress and salinity stress during the dry season; litter accumulated on the forest floor for much of the year, but from November to March was carried away by the higher tides and rainfall. Hence, in the wet season, pulses of litter are exported to the estuary, potentially forming temporary habitats in the estuary for juvenile finfish and crustaceans.

scholarly journals Conservation Status and Habitat Preferences of Common Warthog (Phacochoerus Africanus) in Old Oyo National Park, Nigeria

2021 ◽  
Vol 25 (1) ◽  
pp. 87-92
Author(s):  
A.J. Adeola ◽  
A.I. Adeyemo ◽  
B.N. Ejidike ◽  
O.E. Olaniyi ◽  
O.A. Akande ◽  
...  
Keyword(s):  
Habitat Preference ◽  
National Park ◽  
Conservation Status ◽  
Habitat Preferences ◽  
Dry Season ◽  
Encounter Rate ◽  
Line Transect ◽  
Wet Season ◽  
Abundance Estimate ◽  
The Mean

This study assessed the conservation status and habitat preference of Common warthog in Old Oyo National Park, Nigeria using direct sighting and line transect method. The abundance estimate and encounter rate of common Warthog in the study area from 2018-2019 showed that year 2018 recorded 213 individuals at an encounter rate of 0.38/km while year 2019 recorded 184 individuals at an encounter rate of 0.32/km while the mean abundance estimate of common Warthog are 4.65±0.64 and 1.71±0.48 which represents 156 and 58 individuals at encounter rate of 0.55/km and 0.20/km in the wet season and dry season of year 2018 compared to year 2019 with average abundance estimate value of 4.00±0.85 and 1.41±0.61 which represents 135 and 48 individuals at an encounter rate of 0.47/km and 0.17/km for wet and dry season respectively. The mean age structure and sex ratio of the observed warthog population during dry and wet seasons revealed that juveniles had highest mean of age structures among the populations observed across the seasons. The habitat preference of common warthog revealed that they are mostly found in mixed woodland and open savanna with 112 observation and the lowest was recorded in the outcrop vegetation and open savanna with 21 individuals.in the wet season. During the dry season, mixed woodland/open savanna and Riparian grassland had the highest sightings of 45 and 33 individuals each. The outcrop vegetation/open savanna had the lowest observation of 1 individuals only. The study also recommends that more aspect of the ecology of the animal should be studied in details and emphasis should be placed on the habitat requirements. Keywords: Conservation, Estimate, Status, Warthog

scholarly journals Spatial Organization of the Kasungu Elephant

1983 ◽  
Vol 53 (2) ◽  
pp. 179-186 ◽  
Author(s):  
Hugo Jachmann
Keyword(s):  
Home Range ◽  
Spatial Organization ◽  
Food Competition ◽  
Dry Season ◽  
Home Ranges ◽  
Wet Season ◽  
Activity Area ◽  
The Social ◽  
The Family ◽  
Extended Area

Using a recognition file that was compiled during the study, information on movements of individually known elephants was collected over two periods, one of three and one of eight months, in 1978 and 1981/82, respectively. There appeared to be a relationship between the number of animals in the family unit and the size of the home range/activity area, probably as a result of food competition between the members of a unit. Since 1978 the size of the home range/activity area had decreased in general, as a result of compression by illegal activity. Dry-season home ranges of family units appeared to be rather stable over longer periods and larger than the wet-season home ranges that were situated along the river Lingadzi. Dry-season home ranges of bulls only lasted throughout a single dry season. During the wet season bulls ranged over an extended area. In the later part of the dry season, elephant movements were determined by salt licks and the remaining water holes with a relatively high conductivity, at a distance of the river Lingadzi. The social structure of the family units that made up a kin-group determined the time spent with each other and also appeared to influence the actual size of the home range.

scholarly journals The seasonal changes of the gut microbiome of the population living in traditional lifestyles are represented by characteristic species-level and functional-level SNP enrichment patterns

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Xue Zhu ◽  
Jiyue Qin ◽  
Chongyang Tan ◽  
Kang Ning
Keyword(s):  
Gut Microbiome ◽  
Seasonal Changes ◽  
Dry Season ◽  
Urban Setting ◽  
Snp Analysis ◽  
Wet Season ◽  
Human Gut ◽  
Human Gut Microbiome ◽  
Genome Level ◽  
Prevalent Species

Abstract Background Most studies investigating human gut microbiome dynamics are conducted on humans living in an urban setting. However, few studies have researched the gut microbiome of the populations living traditional lifestyles. These understudied populations are arguably better subjects in answering human-gut microbiome evolution because of their lower exposure to antibiotics and higher dependence on natural resources. Hadza hunter-gatherers in Tanzania have exhibited high biodiversity and seasonal patterns in their gut microbiome composition at the family level, where some taxa disappear in one season and reappear later. Such seasonal changes have been profiled, but the nucleotide changes remain unexplored at the genome level. Thus, it is still elusive how microbial communities change with seasonal changes at the genome level. Results In this study, we performed a strain-level single nucleotide polymorphism (SNP) analysis on 40 Hadza fecal metagenome samples spanning three seasons. With more SNP presented in the wet season, eight prevalent species have significant SNP enrichment with the increasing number of SNP calling by VarScan2, among which only three species have relatively high abundances. Eighty-three genes have the most SNP distributions between the wet season and dry season. Many of these genes are derived from Ruminococcus obeum, and mainly participated in metabolic pathways including carbon metabolism, pyruvate metabolism, and glycolysis. Conclusions Eight prevalent species have significant SNP enrichments with the increasing number of SNP, among which only Eubacterium biforme, Eubacterium hallii and Ruminococcus obeum have relatively high species abundances. Many genes in the microbiomes also presented characteristic SNP distributions between the wet season and the dry season. This implies that the seasonal changes might indirectly impact the mutation patterns for specific species and functions for the gut microbiome of the population that lives in traditional lifestyles through changing the diet in wet and dry seasons, indicating the role of these variants in these species’ adaptation to the changing environment and diets.

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