首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
The coypuMyocastor coypus Molina, 1782 is a semi-aquatic rodent native to Southern South America. In Argentina, it is an important fur resource for rural communities, and there is no evidence of its behaviour as a pest. Between October 2003 and February 2004, studies of habitat use at macro and micro scales were carried out on 6 ponds in a golf course, an artificial urban wetland free from hunting pressure and located within the coypu’s original distribution area. Coypus feed and build their burrows in the ponds but in the absence of hydrophilic vegetation, coypus sought food away from the ponds, covering distances up to 108 m and a feeding area as large as 19 m2. At the macrohabitat scale, the lower the herbaceous vegetation availability at the shore, the greater was the effective usage area. At the microhabitat level, coypus appeared to build their burrows in rather steep slopes (median = 75 cm) or high up on shores rising above the water level (mean = 61.2 cm) selecting ponds with mean values close to the aforementioned figures. The absence of hydrophilous vegetation, natural predators and human activity during the highest activity hours, in addition to suitable food resources around the year are considered to favour the coypu’s behaviour as a pest in these environments.  相似文献   

2.
Many animal species are living in urban areas, where they encounter human‐altered environmental conditions. Artificial light and traffic noise are two of the most prominent anthropogenic factors, both of which potentially affect animal life. Here we studied the changes in traffic noise conditions over the morning in the urban bird habitat of the city of Seville, Spain. We tested experimentally whether noise from human activities can cause a shift in the timing of birdsong activity. Our data revealed that noise conditions vary markedly among our replicate set of twelve streets. Relatively quiet streets show low base‐line amplitude levels early in the morning, with frequent events of brief noise bursts, followed by a strong rise in noise levels. Relatively noisy streets have high base‐line amplitude levels from a much earlier start in the morning. Experimental exposure data revealed a noise‐related earlier start of dawn singing for two out of six species: the spotless starling Sturnus unicolor and the house sparrow Passer domesticus. Our experiment did not cover earlier singing species and revealed no impact for species with more‐variable starting times of the dawn singing. Our study provides more insight into the intertwinings of bird and human behavior and confirms the potential for experimental approaches to successfully tackle questions related to the impact of anthropogenic factors on animal life in cities.  相似文献   

3.

Invasive species often use habitat differently than native species and can benefit by occupying underutilized habitats during the invasion process. The Peter’s Rock Agama (Agama picticauda)—native to savannahs of sub-Saharan Africa—is successfully invading urban habitats in Florida, USA. During a field trip in urban southern Florida, we observed apparently high A. picticauda abundance around dumpsters used for human refuse, potentially because dumpsters provide refuge, thermoregulatory opportunities, abundant arthropod prey, and harbor few competitors. In this study, we surveyed abundance and built resource selection functions to better understand habitat use of A. picticauda in urban southern Florida. We tested whether hypothesized habitat features predictably influenced the abundance and occupancy of A. picticauda among sites and whether individuals used specific habitat features within sites. Across sites, we found A. picticauda abundance was positively correlated with the number of dumpsters, and, within sites, dumpsters were preferentially selected as habitat. Similarly, we also found two other anthropogenic structures, building crevices and electrical units, were positively selected habitats at population and individual scales. We hypothesize that dumpsters, crevices, and electrical units are selected resources because they are underutilized habitats by other species and they provide refuge, beneficial thermoregulatory opportunities, and in the case of dumpsters, foraging opportunities. Our study provides the first quantitative assessment of urban habitat use by non-native A. picticauda, and supports the importance of human structures as habitat. Our results suggest the intriguing possibility that the A. picticauda invasion in Florida may be exploiting a vacant niche in urban habitats during the invasion process.

  相似文献   

4.
Habitat selection of animals is influenced by spatial heterogeneity as well as temporal environmental dynamics. In addition, human activities potentially have severe influences on the habitat selection of animals, often resulting in more nocturnal behavior. We investigated seasonal and circadian habitat selection patterns of red deer (Cervus elaphus) on a military training area in Bavaria (Germany). Individual deer ranged on two neighboring, but non-overlapping sites differing in landscape composition and human activity. Using GPS telemetry data, we visually investigated selection patterns and then fitted step-selection functions to assess multiple approaches to account for temporal (i.e., diel and seasonal) effects and for the impact of habitat conditions on selection. We first showed that the way in which time of day is considered in step-selection functions is essential for obtaining ecologically meaningful results, and that the usual ways of including time (i.e., either based on clock-time or based on night vs. day categories) can lead to incomplete or misleading conclusions. Furthermore, we found that individuals followed either circadian or seasonal habitat selection patterns, depending on the site they inhabited. This can be explained by differences in disturbance between the two sites. Except in winter, individuals selected for open habitats during the night irrespective of human activity level, but only individuals from the more disturbed site selected for covered habitats during the day. Our results highlight the importance of carefully considering the appropriate temporal scale for habitat selection analyses. Our findings also indicate that red deer are not a crepuscular or nocturnal species per se, as is often observed in human-dominated landscapes. Instead, our results imply that nocturnality in red deer is an effect of adaption to human activities.  相似文献   

5.
Harwood’s Spurfowl Pternistis harwoodi is an endemic bird of Ethiopia. Globally, it is categorised as Vulnerable. Habitat loss and hunting are the major conservation threats to the species. This study investigated the activity patterns of Harwood’s Spurfowl in relation to biophysical variables in the Central Highlands of Ethiopia. A species focal sampling method was applied to quantify the time budget of the target species during the dry and wet seasons of 2016. The time spent by the species on various activity patterns were significantly different (p < 0.05). The mean proportion of time utilised by the species for ‘calling’, ‘feeding’, ‘preening’ and ‘resting’ activities based on habitat types and seasons were also statistically different (p < 0.05). Except for ‘resting’, most activity patterns showed bimodal patterns with peaks during the early morning and late in the afternoon. The number of Harwood’s Spurfowl (birds per hour per square metre) detected was higher during the cooler wet season. The highest bird counts occurred during low temperature, low wind speed and high relative humidity in the early morning and late afternoon. The species was recorded most in the scrubland habitat where human disturbance was low. Thus, this habitat should be conserved and managed to sustain the population.  相似文献   

6.
Body size affects key life‐history parameters including dietary requirements and predation risk. We examined these effects on diel habitat use in a community of three sexually‐dimorphic macropodid marsupial species: western grey kangaroo Macropus fuliginosus, red‐necked wallaby M. rufogriseus and swamp wallaby Wallabia bicolor. In particular, our study seeks evidence of these effects operating concurrently at the intra‐ and interspecific levels. We used radio‐tracking to quantify habitat use and characterised each used location by recording the cover of plant functional groups and the presence of plant species. During nocturnal foraging periods we predicted that smaller animals (between and within species) should use habitats with higher‐quality forage, which is often less abundant, than larger animals, as metabolic demand scales with body size. During diurnal resting periods we predicted that smaller animals (between and within species), being more vulnerable to predation, should use greater concealment cover than larger animals. Western grey kangaroos and swamp wallabies behaved as predicted during foraging periods, but red‐necked wallabies did not, using more open, poorer‐quality habitats than expected. Only western grey kangaroos showed a within‐species effect on habitat use: the relatively smaller females foraged in higher‐quality patches. Habitats used by animals during the resting period generally offered greater concealment cover than those used during the foraging period, but there were no clear body size effects on the density of vegetation used. In our system, body size alone could not explain all of the observed patterns, suggesting that there may also be individual differences in habitat requirements influenced by factors such as reproductive costs, predation risk and social facilitation.  相似文献   

7.
Comparisons of sympatric species inhabiting the same ecological habitat may elucidate adaptive processes. We studied the physiological patterns of two species of the genus Limicolaria (L. aurora and L. flammea) that thrive in a hot tropical habitat. We examined changes in water content, biochemical fuel reserves and haemolymph enzyme activities during aestivation and activity. Our results indicate that both species had the potential to conserve body water during aestivation. A definite pattern in foot muscle biochemical fuel reserves was observed. Both species depleted glycogen during aestivation while building up lipids. Catabolism of protein was observed during aestivation. Lactate levels and the activity of lactate dehydrogenase both decreased during aestivation, and both variables later increased at the onset of activity. Significantly higher enzyme activities were recorded during aestivation than during the active period. Stepwise discrimination analysis revealed lactate as the significant predictor of differences between the two periods, with 97.9% of the cases correctly classified. No significant correlation was observed between the measured variables and climatic data. Our results suggest that the physiological adaptation of Limicolaria is not environmentally predictable, rather it is inherently determined for ensuring physiological adjustment for survival in the tropics.  相似文献   

8.
We studied how human presence in three urban parks in Madrid (Spain) might affect Blackbird densities by changing feeding behaviour patterns. Our specific purposes were: (a) to ascertain the effect of park visitors on Blackbird feeding behaviour; (b) to analyse the influence of human disturbance on foraging success; and (c) to determine how humans affect Blackbird spatial and temporal patterns of habitat use. Pedestrians were the main source of flushing responses in all sampled parks, followed by Magpies Pica pica and dogs accompanying visitors. Blackbird responses to visitors entailed more time being vigilant and moving away from people and less time searching for food (decreasing food intake), a response that remained constant in the three parks. The number of pedestrians was positively correlated with Blackbird distance to pathways and negatively correlated with distance to protective cover. The number of active birds decreased with increase in the number of pedestrians during the day. Blackbird density was negatively related to the number of visitors per park. Our results confirmed that human disturbance negatively affects Blackbird feeding strategies in urban parks, ultimately modifying spatial and temporal patterns of habitat selection and abundance. Since such responses could also affect densities of other urban species by the same process, we propose some management measures to decrease the levels of disturbance as well as to enhance the recreational use of urban parks.  相似文献   

9.
1. The hypothesis under test was that larvae of Dinocras cephalotes (Curtis), Perla bipunctata Pictet, Isoperla grammatica (Poda), and Perlodes microcephalus (Pictet) differed markedly in their diel activity and feeding patterns. Mature larvae collected about 1 month prior to adult emergence were used either for gut analyses or for observations of their activity and feeding patterns in three stream tanks with natural substrata and glass bottoms, so that activity could be observed above and below the substratum. A dull red light was used for observations in the dark. Food (larvae of Ephemeroptera, Simuliidae, and Chironomidae) was provided in excess. 2. Larvae for gut analyses were taken 1 h before dusk or dawn (n = 30 larvae per species for each day or night sample). The only species with food in the gut for the day samples was P. microcephalus. All species fed at night, the mean number of prey per larva being very similar for D. cephalotes, P. bipunctata, and I. grammatica but significantly higher for P. microcephalus. Most prey were insect larvae, especially Simuliidae and Chironomidae. 3. Diel activity patterns of single larvae differed interspecifically but not intraspecifically. Larvae of D. cephalotes and P. bipunctata were rarely active during the day; their activity increased at dusk and decreased at dawn, and was highest during the night; their success at prey capture was highest at dusk and dawn, with an ambush rather than a search strategy. Isoperla grammatica was rarely active during the day, most active at dusk and dawn when prey capture was highest, using a search strategy, and less active for the rest of the night. Perlodes microcephalus was active during the day, but only below the substratum, and very active from dusk to dawn with a high prey‐capture success, using a search strategy. These experiments provided support for the hypothesis under test. The discussion concludes that the results could also help to explain known differences in growth rate and the length of the life‐cycle in these four species.  相似文献   

10.
We studied feeding activity and dietary components of hand-reared European roe deer (Capreolus capreolus) in Israel. Our ultimate goal was to assess habitat suitability for future reintroduction of the species, which has been locally extinct for nearly a century. Activity patterns, diet composition, and body mass of four does were monitored in two (fenced) typical east Mediterranean habitats: mature forest and scrubland recovering from fire. Food supplements were provided between trials. Throughout the year, the deer exhibited diurnal and nocturnal activity, mostly at dawn and dusk. Diet composition varied considerably between seasons and habitats, demonstrating the opportunistic flexibility of the deer. In both habitats, the deer fed on over 85% of the plant species but preferred a particular plant species or parts. In summer and early autumn, fruits and seeds became the dominant portion of their diet. In our semi-natural experimental setup, deer maintained body mass through the winter and spring. Weight loss occurred as the dry season advanced, but the animals rapidly regained mass when annuals and grasses became available following the first rains. In the east Mediterranean habitats, water availability seems more problematic for deer survival than food availability.  相似文献   

11.
Organisms living in urban environments are exposed to different environmental conditions compared to their rural conspecifics. Especially anthropogenic noise and artificial night light are closely linked to urbanization and pose new challenges to urban species. Songbirds are particularly affected by these factors, because they rely on the spread of acoustic information and adjust their behaviour to the rhythm of night and day, e.g. time their dawn song according to changing light intensities. Our aim was to clarify the specific contributions of artificial night light and traffic noise on the timing of dawn song of urban European Blackbirds (Turdus merula). We investigated the onset of blackbird dawn song along a steep urban gradient ranging from an urban forest to the city centre of Leipzig, Germany. This gradient of anthropogenic noise and artificial night light was reflected in the timing of dawn song. In the city centre, blackbirds started their dawn song up to 5 hours earlier compared to those in semi-natural habitats. We found traffic noise to be the driving factor of the shift of dawn song into true night, although it was not completely separable from the effects of ambient night light. We additionally included meteorological conditions into the analysis and found an effect on the song onset. Cloudy and cold weather delayed the onset, but cloud cover was assumed to reflect night light emissions, thus, amplified sky luminance and increased the effect of artificial night light. Beside these temporal effects, we also found differences in the spatial autocorrelation of dawn song onset showing a much higher variability in noisy city areas than in rural parks and forests. These findings indicate that urban hazards such as ambient noise and light pollution show a manifold interference with naturally evolved cycles and have significant effects on the activity patterns of urban blackbirds.  相似文献   

12.
Individuals that settle in poor habitats may reduce resource investments in various life history traits; for example, resources may be withheld from costly advertisement signals. There may be geographic variation in advertisement levels that correspond with habitat quality; however, this is poorly documented and it is unclear whether such habitat effects have consequences for the function of mate‐choice signals within habitats. We examined song output of male black‐capped chickadees (Poecile atricapillus) during the dawn chorus in two contrasting habitats (mature forest vs. young forest) known to differ in quality. Dominance rank is indicative of phenotypic quality in this species and was assessed during the preceding winter. We measured the song output of males participating in the dawn chorus during the nesting/egg laying period. Males living in young forest had reduced song output; however, a habitat–rank interaction term showed that dominant birds accounted for most of this difference. This suggests that signal reliability might be lost in poor habitats. We generate several hypotheses to explain these findings.  相似文献   

13.
We investigated the activity patterns of a European roe deer (Capreolus capreolus) population living in a forested Apennine area in central Italy, in order to shed light on the environmental and biological factors that were expected to account for the observed activity patterns on daily and yearly bases. Daily and seasonal activity patterns of 31 radio-collared roe deer were assessed through sessions of radio tracking for a total period of 18 consecutive months. Roe deer showed bimodal activity patterns throughout the year, with the two highest peaks of activity recorded at dawn and dusk. Activity patterns of males and females differed during the territorial period (from early spring to late summer), whereas they did not during the nonterritorial period. Most likely, behavioral thermoregulation can be held responsible for variation of daily activity patterns in different seasons. In winter, for instance, activity during the dawn period was significantly higher than in other seasons and daylight activity was significantly higher than at night. Nocturnal activity was highest in summer and lowest in winter. During the hunting season, moreover, roe deer showed lower activity levels than during the rest of the year. The prediction that roe deer would show lower activity levels during full moon nights, when the predation risk was assumed to be higher, was not confirmed by our data. Activity rhythms in roe deer were thus subjected to both endogenous and environmental factors, the latter working as exogenous synchronization cues. Accordingly, in changing environmental and ecological conditions, a circadian cycle of activity could be seen as the result of complex interactions among daily behavioral rhythm, digestive physiology, and external modifying factors.  相似文献   

14.
Globally, human activities have led to the impoverishment of species assemblages and the disruption of ecosystem function. Determining whether this poses a threat to future ecosystem stability necessitates a thorough understanding of mechanisms underpinning community assembly and niche selection. Here, we tested for niche segregation within an African small carnivore community in Kibale National Park, Uganda. We used occupancy modeling based on systematic camera trap surveys and fine‐scale habitat measures, to identify opposing preferences between closely related species (cats, genets, and mongooses). We modeled diel activity patterns using kernel density functions and calculated the overlap of activity periods between related species. We also used co‐occupancy modeling and activity overlap analyses to test whether African golden cats Caracal aurata influenced the smaller carnivores along the spatial and/or temporal axes. There was some evidence that related species segregated habitat and activity patterns. Specialization was particularly strong among forest species. The cats and genets partitioned habitat, while the mongooses partitioned both habitat and activity period. We found little evidence for interference competition between African golden cats and other small carnivores, although weak interference competition was suggested by lower detection probabilities of some species at stations where African golden cats were present. This suggests that community assembly and coexistence in this ecosystem are primarily driven by more complex processes. The studied carnivore community contains several forest specialists, which are typically more prone to localized extinction. Preserving the observed community assemblage will therefore require the maintenance of a large variety of habitats, with a particular focus on those required by the more specialized carnivores.  相似文献   

15.
We studied the activity patterns of the coyote (Canis latrans) in a tropical deciduous forest in the Mexican Pacific coast over 3 years. Fifteen coyotes (six females, nine males) were fitted with radio-collars equipped with activity sensors to determine the influence of seasonality (dry vs. wet), gender (males vs. females) and diel intervals (dusk, night, dawn, and day) on activity patterns. We found differences in activity patterns between diel intervals, but the only pair of diel intervals that showed significant differences was dawn (more active) vs. day (less active). We found no differences due to sex or season on any of the four studied diel intervals. Coyote activity patterns in this tropical forest could be responding to prey availability, human avoidance or thermoregulation.  相似文献   

16.
Patterns of vocal activity may involve information about vocalizations themselves as well as their function. In birds, vocal activity at the individual and population level is generally closely associated with breeding cycles, reaching the peak during territorial and mating competition, and decreasing with the onset of egg incubation and chick feeding. However, little is known about patterns of vocal activity in avian brood parasites that have unusual breeding cycles without parental care. Using passive acoustic monitoring, we determined the seasonal and diurnal patterns of population vocal activity in two avian brood parasites: the Common Cuckoo Cuculus canorus and the Lesser Cuckoo C. poliocephalus. We found that both species and both sexes showed a similarly highly structured pattern of seasonal vocal activity, reaching a sharp peak in the early breeding season when birds compete for territories and mates, although males sang more frequently than females. Likewise, the diurnal patterns of vocal activity were similar in both species and both sexes of cuckoos, with peak activity occurring around dawn. Nocturnal calls by male cuckoos were also detected in both species, but only in the early breeding season. Collectively, the observed patterns of population vocal activity may suggest that the absence of parental care may not extend the period of vocal activity in these two species of brood parasites.  相似文献   

17.
We examined the migratory strategies of mule deer (Odocoileus hemionus) using adjacent urban and rural winter ranges in northern Utah in relation to deer demography and patterns of habitat use. Urban deer were more likely to be migratory than rural deer, even though migratory animals from the two herds intermixed on a common, high-elevation summer range. Urban deer exhibited lower fawn recruitment than rural deer; but within each herd, demographic characteristics of migratory and nonmigratory animals suggested that game theory explained the ratios of deer adopting each behavior. Estimates of animal numbers and available habitat did not reveal clearly whether deer densities differed on the two winter ranges. However, patterns of habitat use by urban deer were so clustered around areas of concealment vegetation that animals probably experienced higher local densities than rural animals. In addition, the clustered patterns of habitat use by urban deer resulted in incomplete use of available forage. This may have contributed to the relatively poor fawn recruitment by urban deer, a phenomenon that appeared to be perpetuated by their strong fidelity to winter range.  相似文献   

18.
The coypu or nutriaMyocastor coypus Molina, 1782 is a semiaquatic rodent intensively harvested for fur in its native region. We studied population parameters at four sites differing in hunting pressure and characterised hunting activity in north-eastern Buenos Aires province, Argentina. Our interviews with hunters, local inhabitants and wildlife managers revealed that hunting is a cultural tradition in the countryside with the coypu being used as meat and, fur and the young occasionally used as pets. Quarterly live trapping captured a high proportion of all coypus present at each site. In sites with higher hunting pressure, low density of coypus was associated with high population losses and immigration. I n these sites the proportion of juveniles and pregnant females was similar to that obtained at sites with no hunting pressure. No foraging deficiencies were evident from diet quality analysis. Our results suggest that harvesting determines the dynamics of coypu populations in, this region where hunting pressure can be assessed by accessibility of hunting sites, their distance to urban or rural settlements, effective control of hunting, and human population density of the area.  相似文献   

19.
Towards a biogeographic regionalization of the European biota   总被引:1,自引:0,他引:1  
Aim To determine if it is possible to generate analytically derived regionalizations for multiple groups of European plants and animals and to explore potential influences on the regions for each taxonomic group. Location Europe. Methods We subjected range maps of trees, butterflies, reptiles, amphibians, birds and mammals to k‐means clustering followed by v‐fold cross‐validation to determine the pattern and number of regions (clusters). We then used the mean range sizes of species in each group as a correlate of the number of regions obtained for each taxon, and climate and species richness gradients as correlates of the spatial arrangement of the group‐specific regions. We also included the pattern of tree clusters as a predictor of animal clusters in order to test the ‘habitat templet’ concept as an explanation of animal distribution patterns. Results Spatially coherent clusters were found for all groups. The number of regions ranged from three to eight and was strongly associated with the mean range sizes of the species in each taxon. The cluster patterns of all groups were associated with various combinations of climate, underlying species richness gradients and, in the case of animals, the arrangement of tree clusters, although the rankings of the correlates differed among groups. In four of five groups the tree pattern was the strongest single predictor of the animal cluster patterns. Main conclusions Despite a long history of human disturbance and habitat modification, the European biota retains a discernable biogeographic structure. The primary driver appears to be aspects of climate related to water–energy balance, which also influence richness gradients. For many animals, the underlying habitat structure, as measured by tree distributions, appears to have a strong influence on their biogeographic structure, highlighting the need to preserve natural forest formations if we want to preserve the historical signal found in geographic distributions.  相似文献   

20.
Cities are heterogeneous landscapes, with remnant vegetation interspersed amongst areas designed for human use. Native wildlife remaining in urban areas are only likely to thrive and persist if they incorporate human altered areas into what they perceive as habitat. Many sensitive species may be lost if they are restricted to remnant vegetation, and cannot use the urban matrix. In this study, we quantify spatial aspects of the ranging behaviour of Gould's long‐eared bat (Nyctophilus gouldi) using radio‐telemetry and acoustic surveys to determine use of the suburban–bushland interface. This species represents a group prone to extinction due to biological attributes that adapt it to flight within cluttered vegetation, making it more specialized. We radio‐tracked 19 individuals in Cumberland State Forest (CSF), a 40‐ha remnant located in north‐west Sydney, New South Wales, Australia. The nightly range (95% Kernel Density Estimator) was small and localized, and was no greater than 80 ha, where individuals moved on average less than 300 m from roosts each night. All individual N. gouldi tracked used bushland in an almost obligate manner, where up to 100% of used habitat was within local bushland, with little to no use of areas classified as ‘urban’ (residential, commercial and educational land uses). Small open spaces exposed to artificial lighting within the main ranging area of CSF had significantly lower activity (bat passes) of Nyctophilus spp. and significantly higher activity of other species more tolerant of urbanization (P < 0.05). Our results demonstrate that artificial lighting can ‘spill‐over’ into bushland and alter the use of preferred habitat. We conclude that large patches (>40 ha) of protected remnant vegetation must be managed to reduce further degradation, and smaller isolated patches could be restored to provide habitat, particularly in narrow bushland corridors, to assist these species to tolerate urban areas.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号