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1.
Ripley BS  Pammenter NW 《Oecologia》2004,139(4):535-544
Water status in relation to standing biomass and leaf area indices (LAI) of the subtropical foredune species Arctotheca populifolia, Ipomoea pes-caprae and Scaevola plumieri were studied in the Eastern Cape, South Africa. The plants showed little evidence of water stress, never developing leaf water potentials more negative than –1.55 MPa, a value which is typical of mesophytes rather than xerophytes. The plants showed no seasonal changes in osmotic potential, an indication that they did not need to osmoregulate, nor were there significant alterations in tissue elasticity. Turgor potential for the most part remained positive throughout the day or recovered positive values at night, a condition suitable for the maintenance of growth that may be essential to cope with sand accretion. All three species show relatively high transpiration rates and only I. pes-caprae showed any evidence of strong limitations of transpiration rate through reductions in midday stomatal conductance. All three species had relatively high instantaneous water use efficiencies as a result of high assimilation rates rather than low transpiration rates. Simple water budgets, accounting for losses by transpiration and inputs from rainfall, suggest that the water stored in the dune sands is sufficient to meet the requirements of the plants, although water budgets calculated for I. pes-caprae suggest that this species may on occasion be water limited. The results suggest that it is the low biomass and LAI that lead to these favourable water relations.  相似文献   

2.
The chaining of elephants at night is a common management strategy in zoos, yet the costs and benefits of such a strategy are relatively unknown. A study of three unchained female African elephants was undertaken to document their nocturnal behavior. The subjects were observed between the hours of 1800 and 0800 for 10 weeks in the summer of 1992 (total of 172 hr) and 14 weeks in the summer of 1994 (total of 153 hr). Scan data were collected every 5 min to gather information on activity budgets, social proximity, and space utilization. All‐occurrence data were collected on social and non‐social behaviors. In each year of the study, the subjects spent equivalent amounts of time eating, lying, standing, and walking. Additionally, subjects spent half of their time within one body length of another animal and utilized all three available enclosures. Social and non‐social behaviors were frequent, and these data plus the activity profiles reveal the animals generally were most active between the hours of 1800 and 2400 and 0600 and 0700. The findings suggest that the use of no restraints is currently an effective strategy for this elephant group. The high activity levels observed during many of the early evening hours suggest that zoos could permit increased activity and social interactions by extending the hours when the elephants are unchained. Zoo Biol 18:101–109, 1999. © 1999 Wiley‐Liss, Inc.  相似文献   

3.
Grasshoppers must gather food while avoiding size-selective predation from other arthropods, especially spiders, potentially leading to a trade-off between foraging and defensive behaviors. This trade-off becomes less intense as prey grow larger and are less susceptible to arthropod predation. Activity budgets were constructed for three nymphal (third- to fifth- instar) and adult life cycle stages of Ageneotettix deorum, a common rangeland grasshopper, for three conditions of predation risk by lycosid spiders (spider absence, spider presence, and presence of a nonlethal, chelicerae-modified spider). In third and fourth instars, exposure to predators resulted in reduced feeding activity, increased time spent in antipredator and defensive behaviors, and reduced general activity compared to individuals not exposed to spiders. No significant shifts in behaviors were observed for fifth-instar nymphs and adult A. deorum in response to spider presence. Activity levels in functional spiders and chelicerae-modified spiders were statistically indistinguishable.  相似文献   

4.
We investigated the effects of cognitive experiments by direct comparison of activity budgets between wild and captive chimpanzees. One goal of captive management is to ensure that the activity budgets of captive animals are as similar as possible to those of their wild counterparts. However, such similarity has rarely been achieved. We compared the activity budget among three groups of chimpanzees: wild chimpanzees in Bossou (Guinea, n = 10), and captive chimpanzees who participated in cognitive experiments (experimental chimpanzees, n = 6) or did not participate in the experiments (nonexperimental chimpanzees, n = 6) at the Primate Research Institute (Japan). The experimental chimpanzees voluntarily participated in computer‐controlled cognitive tasks and small pieces of fruits were provided as rewards. The data from captivity were obtained on the experimental days (weekdays) and nonexperimental days (weekends). In both study sites, we followed each chimpanzee from about 7 a.m. until the time when chimpanzees started to rest in the evening. The behaviors were recorded every 1 min. The results showed that on weekdays, feeding time and resting time of the experimental chimpanzees were almost the same as those of wild chimpanzees. However, for the nonexperimental chimpanzees, feeding time was significantly shorter and resting time was longer than those of the wild chimpanzees. In contrast, no difference was found in feeding time or resting time of the two groups of captive chimpanzees on weekends. The results suggested that the cognitive experiments worked as an efficient method for food‐based enrichment. Am. J. Primatol. 73:1231–1238, 2011. © 2011 Wiley Periodicals, Inc.  相似文献   

5.
Activity budgets of captive sifakas (Propithecus verreauxi coquereli and Propithecus verreauxi verreauxi) were assessed from 500 hours of observational data obtained at the Duke University Primate Center (Durham, NC). Data were examined for behavioral differences according to gender, availability of intergroup contact, subspecies, indoor/outdoor housing, and enclosure size. Results showed few differences between the activity budgets of males and females. Several differences found in conjunction with availability of intergroup contact appeared to relate more to subspecific, than to contact, differences. Sifakas housed outdoors were more active, spending less time resting and more time in locomotion, feeding, and playing than sifakas housed indoors. The findings of this study implicate outdoor housing as a primary factor in stimulating activity in these rare prosimian primates.  相似文献   

6.
One group of woolly spider monkeys, or muriquis (Brachyteles arachnoides), was observed from June 1983 through July 1984 at Fazenda Montes Claros, Minas Gerais, Brazil. The study subjects spent an average of 49% of their daylight time resting, 29% traveling, and 19% feeding. They shifted their diurnal schedule of activities in response to seasonal changes in temperature and rainfall. The activity budgets of adult males and females were similar. However, a comparison of three adult females in different reproductive conditions revealed that the lactating female spent a greater proportion of time feeding than did both the pregnant and nonreproductive females. Intraspecific differences in group size and diet appear to be important to understanding differences in the activity budgets of Brachyteles. Differences between locomotion patterns of woolly spider monkeys and sympatric howler monkeys may explain activity budget differences based on group size and diet.  相似文献   

7.
Summary Biomass and energy budgets and food utilization efficiencies of laboratory and wild populations of three Central European grasshopper species, Chorthippus parallelus (Zetterstedt), C. biguttulus (L.), and Gomphocerus rufus (L.), were studied between 1979 and 1984. Larval consumption is relatively low in C. biguttulus (C=4.3 kJ/ind.) compared with C. parallelus and G. rufus (4.9 kJ/ind.). In the adult phase (maturity) consumption rates of C. biguttulus and G. rufus (6.9 kJ/ind.) are similar, but higher in C. parallelus (7.3 kJ/ind.). The energy content decreases from the egg (23.2–24.3 J/mg dw) and body tissue (22.1–23.2 J/mg dw) to faeces (16.6–18.1 J/mg dw). The energy contents of faeces differ significantly between the species, indicating different rates of food conversion (on Dactylis glomerata). On average, the assimilation rates are about 30%, slightly lower in G. rufus. Approximate digestibility (A/C) ranges from 28.2 (G. rufus) to 35.7 (C. biguttulus) without great differences between larvae and adults. In contrast, the efficiency of conversion of ingested food (P/C) differs significantly between larval (10–11) and adult stages (3.4–3.6), and so to a much higher degree does the efficiency of conversion of digested food (P/A), from 30.3–33.5 in the larval to 9.5–14.9 in the adult period. Based on 5-year (C. parallelus) and 2-year studies (G. rufus) of the population dynamics and life tables, the energy budgets of wild populations were calculated and summarized into diagrams. Depending on the annually fluctuating densities, in both populations about 1%–2% of net primary production was consumed, and another 5%–9% was cut and dropped. The proportion of production of the grasshopper populations (body tissue) used for egg production differs in C. parallelus (28%) and G. rufus (44%). The energy cycling owing to energy storage in the living eggs amounts to 2%–3% of the total energy consumed by the population. The results are compared with the available data for grasshoppers in the literature.  相似文献   

8.
We introduced two to four unfamiliar animals into three established groups (N = 6–9 per group) of tufted capuchins (Cebus apella).We present findings on the behavioral consequences of introductions as a function of age, sex, and residency status and long-term consequences for health and reproduction. No morbidity from aggression occurred at the time of introductions or during several months following, and reproduction was not compromised. Activity budgets and patterns of social spacing and interaction were little changed following the introductions except for increases in vigilance behavior, especially by newly introduced adult females. Adult females exhibited the strongest and longest-lasting response to changes in group composition. The results indicate that in this species (1) introductions of adult females can be carried out with acceptable risk to the newcomers provided that careful monitoring occurs, so that the onset of severe aggression instigated by resident females toward new females can be avoided, (2) juveniles can be introduced with minimal risk, and (3) adult males can be introduced into groups lacking resident adult males with minimal risk. Capuchins differ in important ways from the better-studied Old World monkeys in their response to introductions of strangers. The differences are instructive with regard to processes supporting species-typical social structure, which is less overtly hierarchical in capuchins than in macaques.  相似文献   

9.
This research was conducted on a captive group of eight wild boars: Four wildborn adults (one male and three females) and four piglets (one male and three females), born in captivity two months before the beginning of the study. They were housed in the Rome Zoo in a 1,000 sq m enclosure furnished with trees, mud pools, a water basin, and two small barns. Data on eight behavioral states (sleeping, resting, rooting, eating, walking, standing, scratching, and nursing) were collected by instantaneous sampling at 10-minute intervals. The spatial location of each subject was also noted, as well as closeness to conspecifics. Results showed that adults and piglets differed in their activity budgets. Activity patterns showed a significant correlation with the mean temperatures. Furthermore, there was a significant difference in the use of the exhibit areas between adults and piglets. This study suggests a social structure in which the core is constituted by females and their yearlings. The nonbreeding female has a more marginal position than the breeding ones. Finally, the male tends to be even more peripheral and solitary. Our results are partly consistent with the data obtained in studies on free-ranging wild boars (Mauget, 1980; Dardaillon, 1984).  相似文献   

10.
Diurnal time-activity budgets were determined for wintering redheads (Aythya americana) from estuarine seagrass beds in Louisiana (Chandeleur Sound) and Texas (Laguna Madre) and from ponds adjacent to the Laguna Madre. Activities differed (p<0.0001) by location, month, and diurnal time period. Resting and feeding were the most frequent activities of redheads at the two estuarine sites, whereas drinking was almost nonexistent. Birds on ponds in Texas engaged most frequently in resting and drinking, but feeding was very infrequent. Redheads from the Louisiana estuarine site rested less than birds in Texas at either the Laguna Madre or freshwater ponds. Redheads in Louisiana fed more than birds in Texas; this was partially because of weather differences (colder temperatures in Louisiana), but the location effect was still significant even when we adjusted the model for weather effects. Redheads in Louisiana showed increased resting and decreased feeding as winter progressed, but redheads in Texas did not exhibit a seasonal pattern in either resting or feeding. In Louisiana, birds maintained a high level of feeding activity during the early morning throughout the winter, whereas afternoon feeding tapered off in mid- to late-winter. Texas birds showed a shift from morning feeding in early winter to afternoon feeding in late winter. Males and females at both Chandeleur Sound and Laguna Madre showed differences in their activities, but because the absolute difference seldom exceeded 2%, biological significance is questionable. Diurnal time-activity budgets of redheads on the wintering grounds are influenced by water salinities and the use of dietary fresh water, as well as by weather conditions, tides, and perhaps vegetation differences between sites. The opportunity to osmoregulate via dietary freshwater, vs. via nasal salt glands, may have a significant effect on behavioral allocations.  相似文献   

11.
2007年11月、12月和2008年3月,在内蒙古达赉湖地区,采用扫描取样法对雌雄蒙原羚繁殖期及其前后昼间行为时间分配进行了研究。 研究表明:(1)繁殖期前、繁殖期和繁殖期后,雌性蒙原羚采食时间,占昼间活动时间的比例分别为(44.9±3.8)%、(43.5±4.0)% 和 (46.2±3.1)%;卧息时间,占昼间活动时间的比例分别 为(32.3±4.8)%、(29.2±2.9)% 和 (28.0±4.8)%;雌性蒙原羚在繁殖期及其前后采食、移动和卧息的行为时间分配差异不显著(P>0.05),站立、繁殖、“其他”行为时间分配差异性显著(P<0.05)。(2)繁殖期前、繁殖期和繁殖期后, 雄性蒙原羚采食时间,占昼间活动时间的比例分别为 (52.6±3.8)%、(17.5±2.8)% 和 (29.8±4.8)%;卧息时间,占昼间活动时间的比例分别为 (13.4±6.4)%、(24.2±4.1)% 和 (44.2±4.7)%。雄性蒙原羚在繁殖期及其前后采食、卧息、站立、移动、繁殖、“其他”时间分配均有显著差异(P<0.05)。动物采食卧息的行为时间分配反映动物的能量平衡策略。雌性蒙原羚的时间分配表明,雌性蒙原羚的能量平衡策略在繁殖期前、繁殖期和繁殖期后没有发生显著变化,均为能量摄入最优化策略,尽可能多的时间分配在采食上;雄性蒙原羚的时间分配表明,在繁殖期前,其能量平衡策略为能量摄入最优化策略,尽可能多的时间分配在采食上;雄性蒙原羚繁殖期及繁殖期后其能量平衡策略转变为能量支出优化策略,尽可能少的支出能量,尽可能多的时间分配在卧息上。  相似文献   

12.
We conducted extensive behavioral and food sampling of Atlantic brant (Branta bernicla hrota) across their winter range and used time–activity budgets for brant to determine daily energy expenditure (DEE). Sampling occurred 1 December–31 May 2006–2008 in 11,225-km2 sites between Rhode Island and Virginia containing important estuarine and upland habitat. To calculate DEE we used instantaneous scan sampling to estimate time–activity budgets. We also determined foods eaten by brant and energy density of food plants. Last, we quantified body condition of brant, which differed among years, months, regions, and ages, and sexes. Overall DEE for brant was 1,530 ± 64 kJ/day. There was considerable variation in time–activity budgets among years, months, regions, habitat, tide, temperature, and time-of-day, but we detected no significant difference in DEE of brant between years or among regions. However, DEE in January (2,018 ± 173 kJ/day) was nearly double the DEE of brant in May (1,048 ± 137 kJ/day). Brant spent their time feeding (32.3%), swimming (26.2%), resting (16.2%), and flying (14.5%). The percent of brant foreguts sampled contained macroalgae (53%) eelgrass (Zostera marina; 18%), salt marsh cordgrass (Spartina alterniflora; 17%), and terrestrial grass (Poa. sp.) and clover (Trifollium sp.; 9%). Energy density differed by vegetation type: macroalgae (12.6 ± 0.1 kJ/g), eelgrass (14.1 ± 0.1 kJ/g), new-growth salt marsh cordgrass (16.9 ± 0.2 kJ/g), and terrestrial grass and clover (17.7 ± 0.1 kJ/g). Atlantic brant exhibited behavioral plasticity thereby allowing modification of daily activity budgets to meet seasonally varying energetic requirements associated with wintering and spring staging. Recognizing a variable DEE can be used along with eventual estimates of food biomass and total metabolizable energy on the landscape to calculate carrying capacity (goose use days) on state, region, or range-wide scales. © 2011 The Wildlife Society.  相似文献   

13.
Synopsis Sixty-nine individuals of Plecodus straeleni were followed for 1 h each in the field with the aid of SCUBA, and time budgets, hunting techniques and prey selection were investigated in relation to sex and body size. The time of cruising in midwater and on the substrate amounted to 3/4 of the total time. The rest of the time was mainly spent on five hunting techniques named pursuing, waiting, mingling, aiming and stealthy approaching. Pursuing (following a flying prey at high speed) was frequently used by adults, especially males, mainly to attack the spiny eel Afromastacembelus moorii. Waiting (keeping motionless on the substrate, waiting for a known prey) was used by some adult females when they tried to steal eggs of the mouthbrooder Cyathopharynx furcifer on the bower and by adult males when they targeted an eel having hidden under a rock. Mingling (mixing in a school of prey to attack school members) was a favorite tactic of subadults to attack plankton-feeders. Aiming (directing the head to a target fish for a moment) commonly occurred when both adults and subadults attacked solitary fishes. In stealthy approaching, the scale-eater approached an unwary prey from behind or sideway. Attacks by these hunting techniques amounted to 97% of the total attacks, which were made on 38 cichlid species and 7 non-cichlid species. Hunting techniques and prey preference varied not only with sex and size but even among consexuals of similar sizes. A number of individuals successively attacked only one or a few prey species in 1 h. Food specialization among individuals was attributed to their learning of the behavior and life style of preferred prey species.  相似文献   

14.
Evers  David C. 《Hydrobiologia》1994,(1):415-420
A newly devised nightlighting technique was used to capture breeding adult common loons (Gavia immer) at the Seney National Wildlife Refuge in northern Michigan in 1989. The behaviors of 6 pairs of known-sex, color-marked common loons were subsequently quantified during the breeding cycle in 1990. Collected observational data indicate that foraging, resting, locomotion, and preening were frequent throughout the breeding cycle. Time spent foraging was greatest during the pre-nesting period (53 to 57%), but declined significantly during the nesting and post-nesting periods (p<0.05). Time spent foraging during the pre-nesting period was similar to that of fall and winter studies. During the pre-nesting period adult loons spent about 15% of the time in locomotion; this was significantly greater than the other time periods (p<0.05) and is attributed to selecting a nest site. During the nesting cycle, almost half of each bird's time spent was nest-sitting. Sexual differences were negligible during nest-sitting. Resting and chick-rearing were the predominant behaviors during the post-nesting period and were responsible for the biggest difference in parental duties. Time spent preening declined from 8% during the pre-nesting period to 4 to 5% during the post-nesting period. Time spent by nesting pairs to produce chicks is approximately 10% during pre-nesting, 48 to 49% during nesting, and between 38 to 44% during post-nesting. By quantifying and establishing behavioral standards, subtle abnormalities or changes can be detected to better manage for viable common loon populations.  相似文献   

15.
Activity patterns and time budgets are 2 important aspects of animal behavior that researchers use to investigate ecological influences on individual behavior. We collected data on activity patterns and time budgets in 1 group of François’ langurs (Trachypithecus francoisi) from August 2003 to July 2004 in the Nonggang Nature Reserve, Guangxi Province, China, via instantaneous scan sampling method with 15-min intervals. The diurnal activity pattern of François’ langurs showed morning and afternoon feeding peaks, with a midday resting peak. Seasonal change was apparent in the activity pattern: 2 significant feeding peaks occurred in the dry season and only 1 significant feeding peak in the rainy season. The group spent an average of 51.5% of the daytime resting. Feeding and moving accounted on average for 23.1% and 17.3% of the activity budget, respectively. Subjects spent little time on social activities, averaging 2% for grooming and 5.5% for playing. Their time budgets showed significant seasonal variation: they spent a greater proportion of time on feeding and less time on resting and grooming in the dry season than in the rainy season. They also differed among different sex-age classes: immatures spent more time playing, whereas adults devoted more time to resting, feeding, and grooming. Correlations between time budgets and food items or food availability clearly indicated that François’ langurs might adopt an energy-maximizing strategy when preferred foods were scarce in the dry season.  相似文献   

16.
Data on the time budgets of mountain gorillas (Gorilla gorilla beringei) were collected during field studies in the Virunga Volcanoes region of Rwanda and Zaire. Focal sampling was used to determine the proportion of time that individuals of different age/sex classes spent in several mutually exclusive activity states. The gorillas spent the majority of daylight hours feeding; most of the rest of the day was devoted to resting, with little time spent moving or engaged in social activity. The time budget varied among the different subhabitats used by the gorillas, and the gorillas satisfied subsistence needs more quickly when in areas where food was more abundant and/or of better nutritional quality. Silverbacks spent more time feeding than all other age/sex classes, but age/sex class differences were not great. All age/sex classes responded to variability in habitat quality in similar fashion. Unlike the case for many other primates, there was no significant seasonal variation in time budgets. There was a direct relationship between group size and time spent feeding, although variation in relation to group size was lower than that in relation to variation in habitat quality. These results are consistent with the relationship of feeding time to body size in primates. They are also consistent, with other evidence that social foraging entails a cost to gorilla females, but that this cost is low in comparison to those faced by many other primates. Permanent association with males apparently offers little ecological disadvantage to females, who are likely to be more than compensated by mutualistic benefits.  相似文献   

17.
18.
I studied a group of woolly monkeys (Lagothrix lagotricha)for 1800 hr from early 1985 until September 1987 near the lower Apaporis river of the Vaupés Department in the eastern Colombian Amazon. The group had an activity budget of 29.9% rest, 38.8% move, 25.8% forage, and 5.5% other activities during 720 hr of observations evenly spaced throughout this year. The only significant change in these activities during the study period was social activity, which increased as a function of increased food supply. Average diurnal activities of resting and moving are negatively correlated, and each activity show significant changes during the day, while foraging show no significant change. The activity budgets of the adult males and females are not significantly different, but the activities of the juveniles and infants showed much more social activity than the adults. High moving scores may be correlated with the comparative infertility of the soils of the Caparú forest, which require increased effort to maintain the energy levels necessary for maintenance and reproduction in Lagothrix.  相似文献   

19.
Biologging devices are providing detailed insights into the behaviour and movement of animals in their natural environments. It is usually assumed that this method of gathering data does not impact on the behaviour observed. However, potential negative effects on birds have rarely been investigated before field-based studies are initiated. Seabirds which both fly and use pursuit diving may be particularly sensitive to increases in drag and load resulting from carrying biologging devices. We studied chick-rearing adult common guillemots Uria aalge equipped with and without back-mounted GPS tags over short deployments of a few days. Concurrently guillemots carried small leg-mounted TDR devices (time-depth recorders) providing activity data throughout. Changes in body mass and breeding success were followed for device equipped and control guillemots. At the colony level guillemots lost body mass throughout the chick-rearing period. When-equipped with the additional GPS tag, the guillemots lost mass at close to twice the rate they did when equipped with only the smaller leg-mounted TDR device. The elevated mass loss suggests an impact on energy expenditure or foraging performance. When equipped with GPS tags diving performance, time-activity budgets and daily patterns of activity were unchanged, yet dive depth distributions differed. We review studies of tag-effects in guillemots Uria sp. finding elevated mass loss and reduced chick-provisioning to be the most commonly observed effects. Less information is available for behavioural measures, and results vary between studies. In general, small tags deployed over several days appear to have small or no measurable effect on the behavioural variables commonly observed in most guillemot tagging studies. However, there may still be impacts on fitness via physiological effects and/or reduced chick-provisioning, while more detailed measures of behaviour (e.g. using accelerometery) may reveal effects on diving and flight performance.  相似文献   

20.
Behavioural observations were carried out on grey rhebok and mountain reedbuck at Sterkfontein Dam Nature Reserve, South Africa, for a period of 1 year between May 2001 and April 2002. Four harem herds of grey rhebok, five territorial male mountain reedbuck and female mountain reedbuck (herds grouped as one individual) were monitored to determine activity budgets and activity patterns. Both species spent more time feeding in the late afternoon during relatively cool temperatures, and more time resting in the middle of the day during relatively high temperatures. Statistical comparisons between the two species of the percentage time feeding and resting found no differences between them, although mountain reedbuck spent more time resting overall than grey rhebok. Both species were active at night.  相似文献   

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