摘要 :
Many translocation methods have been tested in southern Europe in recent decades to increase the translocation success of the European wild rabbit (Oryctolagus cuniculus L.) for both conservation and game purposes. The main proble...
展开
Many translocation methods have been tested in southern Europe in recent decades to increase the translocation success of the European wild rabbit (Oryctolagus cuniculus L.) for both conservation and game purposes. The main problem experienced during such translocations is the high short-term (7 days) mortality attributed to predation during the days immediately following rabbit release. In this study, we test the effect of the exclusion of terrestrial predators on the survival of translocated rabbits for recovery purposes. Four translocation plots (4 ha with 18 artificial warrens each) were constructed, two of them with a fence to exclude terrestrial predators. In all, 724 rabbits were released to the translocation plots in five batches and forced to remain inside warrens for 7 days. Following liberation, exclusion of predators did not increase rabbit survival in the short term. Contrary to expectations, three months after release, survival of rabbits in the unfenced plot was slightly, but not significantly, higher than in the fenced plot (0.57 and 0.40 respectively). Although predator control is a frequent management practice associated with rabbit translocations, our results suggest that it may not favour rabbit survival rate as much as the adaptation of rabbits to the release site.
收起
摘要 :
We present data on the spread of terrestrial activities in one group of wild northern muriqui monkeys (Brachyteleshypoxanthus). Both males and-females consumed fruit, drank, rested, traveled, and socialized terrestrially, but prop...
展开
We present data on the spread of terrestrial activities in one group of wild northern muriqui monkeys (Brachyteleshypoxanthus). Both males and-females consumed fruit, drank, rested, traveled, and socialized terrestrially, but proportionately moremales spent significantly more of their time on the ground than females, and females were more likely to engage in terrestrial activitieswhen accompanied by males than when by themselves. Terrestrial activities occurred in both open and closed habitats where arborealsubstrates were available and utilized by other individuals engaged in similar activities. Ecological and demographic factors may havestimulated the muriquis' vertical niche expansion, but increases in the frequency and diversity of terrestrial activities, the high proportionof group members that engage in terrestriality, and its diffusion along male-biased social bonds are consistent with the development ofa local terrestrial tradition similar to other types of traditions described in other primates.
收起
摘要 :
CROCODILIANS are generally considered to be specialised predators hunting in the water or at the water edge (Neil, 1971). Their terrestrial activities such as nesting, migrating, aestivating/ hibernating and basking are well known...
展开
CROCODILIANS are generally considered to be specialised predators hunting in the water or at the water edge (Neil, 1971). Their terrestrial activities such as nesting, migrating, aestivating/ hibernating and basking are well known and documented in most overviews of crocodilian biology. Despite abundant anecdotal evidence of terrestrial hunting (mostly in the form of scary campfire stories), this aspect of crocodilian behaviour has never been studied nor scientifically described. Observations made during a study of crocodilians in the wild in 2006-2010, mostly on American alligator ( Alligator mississippiensis), Nile crocodile (Crocodylus niloticus), and to a lesser extent on other species, suggest that terrestrial hunting may be more common than previously thought.
收起
摘要 :
A terrestrial predator population, the pine marten (Martes martes, L.), inhabiting an area in mid-Sweden was investigated for polychlorinated biphenyls, p,p'-DDE, lindane, and hexachlorobenzene. The condition of the animals, as sh...
展开
A terrestrial predator population, the pine marten (Martes martes, L.), inhabiting an area in mid-Sweden was investigated for polychlorinated biphenyls, p,p'-DDE, lindane, and hexachlorobenzene. The condition of the animals, as shown by intestine fat amounts or fat content of muscle tissue, showed negative relationships with concentration of persistent pollutants. The relationship resulted in a higher concentration of pollutants as intestinal fat amounts or muscle fat content decreased and lower levels of pollutants as these indexes of condition improved.
收起
摘要 :
Spider monkeys (Ateles spp.) are well known for their highly arboreal lifestyle, spending much of their time in the highest levels of the canopy and rarely venturing to the ground. To investigate terrestriality by Ateles and to il...
展开
Spider monkeys (Ateles spp.) are well known for their highly arboreal lifestyle, spending much of their time in the highest levels of the canopy and rarely venturing to the ground. To investigate terrestriality by Ateles and to illuminate the conditions under which spider monkeys venture to the ground, we analyzed ad libitum data from 5 study sites, covering 2 species and 5 subspecies. Three of the sites are in Central/North America: Barro Colorado Island (BCI), Panama (Ateles geoffroyi panamensis), Santa Rosa National Park, Costa Rica (A. g. frontatus), and Punta Laguna, Mexico (A. g. yucatanensis). The 2 remaining sites are in South America: Cocha Cashu Biological Station, Perú (A. belzebuth chamek) and Yasuni National Park, Ecuador (A. b. belzebuth). Terrestrialism by Ateles at all sites is rare; however, it is more restricted at the 2 South American sites. In South America, ground use only occurred in the contexts of eating soil or rotten wood and visiting salt licks. In contrast at the 3 sites with Ateles geoffroyi it rarely occurred in a feeding context, but instead more frequently while drinking from streams during the dry season, by adult females escaping attack by adult males, and as part of a chase game. In addition, on BCI adult males were on the ground before attacking adult females. We discuss potential explanations, e.g., climate, species differences, predation pressure, for the differences between the Central/North and South American observations.
收起
摘要 :
A knowledge of food habits is important for evaluating interspecific competition and predation between sympatric species. Data on food availability should be combined with data on food habits in this type of survey. Although food ...
展开
A knowledge of food habits is important for evaluating interspecific competition and predation between sympatric species. Data on food availability should be combined with data on food habits in this type of survey. Although food availability differs between habitats or seasons, these differences had never been considered in previous studies. We conducted year-round field surveys throughout a stream to compare the food habits of an introduced salmonid, brown trout Salmo trutta, and a native salmonid, masu salmon Oncorhynchus masou. Masu salmon did not constitute a large proportion of the diet of brown trout and vice versa. Thus, predation will likely not affect the population level of either species. The dietary overlap between brown trout and masu salmon varied depending on the presence of Gammaridae and terrestrial invertebrates; i.e., the intensity of interspecific competition for food resources may differ according to food conditions.
收起
摘要 :
Organohalogen pollutants (OHPs), including dichlorodiphenyl trichloroethane and its metabolites (DDTs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), hexabromocyclod-odecanes (HBCDs), and dechlorane plu...
展开
Organohalogen pollutants (OHPs), including dichlorodiphenyl trichloroethane and its metabolites (DDTs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), hexabromocyclod-odecanes (HBCDs), and dechlorane plus (DP), were determined in three raptor species, namely, the common kestrel (Falco tirmiinculus), eagle owl (Bubo bubo), and little owl (Athene noctua), as well as in their primary prey items: Eurasian tree sparrow (Passer montanus) and brown rat {Rattus norvegicus). DDTs were the predominant pollutants in avian species followed by PBDEs and PCBs, then minimally contribution of HBCDs and DP. Inter-species differences in the PBDE congener profiles were observed between the owls and the common kestrels, with relatively high contributions of lower brominated congeners in the owls but highly brominated congeners in the kestrels. This result may partly be attributed to a possible greater in vivo biotransformation of highly brominated BDE congeners in owls than in kestrels. α-HBCD was the predominant diastereoisomer with a preferential enrichment of (-)-enantiomer in all the samples. No stereoselective bioaccumulation was found for DP isomers in the investigated species. Biomag-nification factor (BMF) values were generally higher in the rat-owl food chain than in the sparrow-kestrel food chain. Despite this food chain-specific biomagnification, the relationships between the log BMF and log K_(ow) of PCBs and PBDEs followed a similar function in the two food chains, except for BDE-47, -99, and -100 in the sparrow-kestrel feeding relationship.
收起
摘要 :
The aim of this study is to assess the occurrence of human litter ingested by arctic foxes (Vulpes lagopus) caught in Svalbard, Norway, in winter when scavenging is at its highest. Twenty arctic fox stomachs and intestines were ex...
展开
The aim of this study is to assess the occurrence of human litter ingested by arctic foxes (Vulpes lagopus) caught in Svalbard, Norway, in winter when scavenging is at its highest. Twenty arctic fox stomachs and intestines were examined for human litter and plastic using the protocol from the Oslo-Paris Convention (OSPAR) for monitoring plastic ingestion by the northern fulmar (Fulmarus glacialis) (human litter and plastic >1 mm). The arctic foxes had ingested human litter at a low frequency (15%, 3 out of 20 foxes). Despite the low sample size, we do not regard ingestion of human litter as an immediate threat to the arctic fox population in Svalbard.
收起
摘要 :
Predator avoidance and foraging often pose conflicting demands. Animals can decrease mortality risk searching for predators, but searching decreases foraging time and hence intake. We used this principle to investigate how prey sh...
展开
Predator avoidance and foraging often pose conflicting demands. Animals can decrease mortality risk searching for predators, but searching decreases foraging time and hence intake. We used this principle to investigate how prey should use information to detect, assess and respond to predation risk from an optimal foraging perspective. A mathematical model showed that solitary bees should increase flower examination time in response to predator cues and that the rate of false alarms should be negatively correlated with the relative value of the flower explored. The predatory ant, Oecophylla smaragdina, and the harmless ant, Polyrhachis dives, differ in the profile of volatiles they emit and in their visual appearance. As predicted, the solitary bee Nomia strigata spent more time examining virgin flowers in presence of predator cues than in their absence. Furthermore, the proportion of flowers rejected decreased from morning to noon, as the relative value of virgin flowers increased. In addition, bees responded differently to visual and chemical cues. While chemical cues induced bees to search around flowers, bees detecting visual cues hovered in front of them. These strategies may allow prey to identify the nature of visual cues and to locate the source of chemical cues.
收起
摘要 :
The African Penguin Spheniscus demersus is an endangered seabird endemic to southern Africa, and killing sprees by terrestrial predators have been one of the main threats for its mainland colonies. The methods employed to manage p...
展开
The African Penguin Spheniscus demersus is an endangered seabird endemic to southern Africa, and killing sprees by terrestrial predators have been one of the main threats for its mainland colonies. The methods employed to manage predators may differ depending on the species involved, therefore the implementation of strategies to limit the impacts of predation relies on the correct identification of the culprit predator. We report and quantify the lesions seen in African Penguins killed by four species of terrestrial predators: Caracal Caracal caracal (52 kills), Leopard Panthera pardus (27 kills), Domestic Dog Canis lupus familiaris (10 kills), and Cape Grey Mongoose Galerella pulverulenta (4 kills). We discuss patterns of necropsy findings that can be used to identify the predator species involved. Traditional forensic methods are useful tools to direct species-specific management actions for the conservation of the African Penguin and other seabirds so that effective mitigating measures can be deployed quickly to prevent further losses. It should be borne in mind, however, that the age, size and previous hunting experience of the predator are likely to influence the pattern of lesions that will be observed, and not all carcasses will have hallmark lesions or recognisable bite marks.
收起
原文获取