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1.
Willem‐Jan Emsens Lennart Suselbeek Ben T. Hirsch Roland Kays Annemarie J. S. Winkelhagen Patrick A. Jansen 《Biotropica》2013,45(1):88-93
Animals that rely on refuges for safety can theoretically increase their foraging area without simultaneously increasing predation risk and travel costs by using more refuges. The key prediction of this theory, a negative correlation between food abundance, home range size and the number of refuges used, has never been empirically tested. We determined how home range size and refuge use by the Central American agouti (Dasyprocta punctata) varied across a gradient of abundance of the agoutis' principal food source: seeds and fruits of the palm Astrocaryum standleyanum. We used both manual and automated radio telemetry to measure space use of 11 agoutis during 2 mo of the Astrocaryum fruiting season, and of another set of 10 agoutis during 6 mo in which the animals largely relied on cached Astrocaryum seeds. We found that agoutis living in areas of lower food density had larger home ranges, and that all individuals used multiple refuges. The number of refuges, however, was not correlated with home range size. Consequently, agoutis that had larger home ranges roamed farther from their refuges. These results suggest that agoutis increase their home range size in response to food scarcity at the cost of their safety. 相似文献
2.
Coral reefs have recently experienced an unprecedented decline as the world's oceans continue to warm. Yet global climate models reveal a heterogeneously warming ocean, which has initiated a search for refuges, where corals may survive in the near future. We hypothesized that some turbid nearshore environments may act as climate‐change refuges, shading corals from the harmful interaction between high sea‐surface temperatures and high irradiance. We took a hierarchical Bayesian approach to determine the expected distribution of 12 coral species in the Indian and Pacific Oceans, between the latitudes 37°N and 37°S, under representative concentration pathway 8.5 (W m?2) by 2100. The turbid nearshore refuges identified in this study were located between latitudes 20–30°N and 15–25°S, where there was a strong coupling between turbidity and tidal fluctuations. Our model predicts that turbidity will mitigate high temperature bleaching for 9% of shallow reef habitat (to 30 m depth) – habitat that was previously considered inhospitable under ocean warming. Our model also predicted that turbidity will protect some coral species more than others from climate‐change‐associated thermal stress. We also identified locations where consistently high turbidity will likely reduce irradiance to <250 μmol m?2 s?1, and predict that 16% of reef‐coral habitat ≤30 m will preclude coral growth and reef development. Thus, protecting the turbid nearshore refuges identified in this study, particularly in the northwestern Hawaiian Islands, the northern Philippines, the Ryukyu Islands (Japan), eastern Vietnam, western and eastern Australia, New Caledonia, the northern Red Sea, and the Arabian Gulf, should become part of a judicious global strategy for reef‐coral persistence under climate change. 相似文献
3.
Peter H. OBrien 《Applied animal behaviour science》1984,12(4):373-385
The daily range of feral goats varied in relation to social class and environmental variables. Mean daily ranges for 5 social classes were: male herd, 3.52 × 105 m2; female herd, 2.12 × 105 m2; composite herd, 1.86 × 105 m2; stayer female, 0.57 × 105 m2; creche group, 0.39 × 105 m2. Total recorded home range was male herd 14.8 × 105 m2 and female herd 9.65 × 105 m2. Female herd daily range varied seasonally in terms of size, location and habitat utilization. Female herd daily range area was correlated significantly with number of days since rain (r = 0.412), amount of rain in the past 30 days (r = ?0.296), maximum daily temperature (r = ?0.409), and minimum daily temperature (r = ?0.523), but not with wind velocity in the morning (r = ?0.064) or afternoon (r = ?0.137). 相似文献
4.
Breeding waterbird wetland habitat availability and response to water-level management in Saint John River floodplain wetlands, New Brunswick 总被引:4,自引:0,他引:4
Vegetated areas of rivers and estuaries are capable of affecting the concentration of dissolved and particulate matter in
water masses traversing those plant beds. We examined whether different sizes of water chestnut (Trapa natans) beds in the Hudson River, USA, alter dissolved oxygen, nutrients and turbidity of water masses. Ebb–tide water was sampled
from four water chestnut beds in the tidal freshwater portion of the Hudson River estuary and each site was sampled multiple
times during the growing season and once following plant senescence. Water quality variables included dissolved oxygen, turbidity,
dissolved organic carbon, and inorganic nutrients. Samples from the small beds (575 m2 and 624 m2) were compared with large beds (16 600 m2 and 24 820 m2). Dissolved oxygen of water flooding vegetated beds in the hour before high tide was 7.18±1.03 mg/l (mean±standard deviation)
with a range of 5.5–9.8 mg/l throughout the growing season. Water samples collected as water ebbed from the plant beds showed
that only the large beds had an effect on dissolved oxygen with the largest declines in oxygen exhibited by the largest bed.
Decline of dissolved oxygen in the water ebbing from the largest bed averaged 1.5±0.4 mg/l/h with a minimum of 4.5 mg/l, equivalent
to 54% of saturation, a level at which sensitive fauna are negatively affected. There were no significant relationships between
bed size or plant presence and inorganic nutrients, turbidity or DOC. Ebb–tide nitrate was never lower than 87% of flood tide
means. Effective management of invasive plants must consider both the variability in effects among plant beds and the areal
coverage of plant bed sizes. 相似文献
5.
Chiemchaisri W Chiemchaisri C Dumrongsukit C Threedeach S Ngo HH Vigneswaran S 《Bioresource technology》2011,102(9):5438-5443
Floating plastic media pre-filter (PP) in combination with microfiltration membrane (MF) was applied to the removal of water-borne microorganism from surface water. The system was operated with and without coagulant addition. Jar-test results suggested that alum and polyaluminum chloride could effectively remove turbidity, fecal coliforms (FC) and algae at their optimum doses. Nevertheless, none of those coagulants could accomplish high coliphage (CP) removal. Microorganism removal in the system was increasing along with time in the PP unit operated at 5-m3/m2/h filtration rate but opposite trend was observed at higher filtration rates (10-15 m3/m2/h). Different coagulant types and filtration rates employed in the PP unit also affected microorganism removal in MF unit. The operation of PP unit at a filtration rate of 15 m3/m2/h and MF unit at a filtration rate of 0.6 m3/m2/d could achieve satisfactory turbidity and overall microorganism removal. 相似文献
6.
Lake Vesijärvi, southern Finland, suffered sewere eutrophication by sewage effluent from the city of Lahti during the 1960's and the early 1970's. The municipal sewage loading was diverted from the lake in 1976 and the lake started to recover. However, in the 1980's blue-green algal blooms increased again and the recovery of the lake faded. Enclosure experiments demonstrated that high roach (Rutilus rutilus) biomass is one of the key factors in the fading recovery of the lake. In this study, the influence of roach and another cyprinid fish species (bleak, Alburnus alburnus) to planktonic algal productivity and biomass in Lake Vesijärvi was examined. Enclosure experiments in the field showed the impacts of planktivorous bleak on water quality; in an enclosure with a density of 1 fish m–2 average daily algal production (1370 mg C m–2) and chlorophyll-a concentration (50–90 µg 1–1) were more than twice that in an enclosure without fish. Laboratory experiments showed that the availability of planktonic food affects the foraging behaviour of roach and consequently the internal nutrient loading from the sediment into the water. Roach caused the highest phosphorus loading and turbidity when there was no zooplanktonic food available in the water. The possible interactions between planktivorous and omnivorous fish species are discussed. 相似文献
7.
Light availability affects stream biofilm bacterial community composition and function,but not diversity
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Karoline Wagner Katharina Besemer Nancy R. Burns Tom J. Battin Mia M. Bengtsson 《Environmental microbiology》2015,17(12):5036-5047
Changes in riparian vegetation or water turbidity and browning in streams alter the local light regime with potential implications for stream biofilms and ecosystem functioning. We experimented with biofilms in microcosms grown under a gradient of light intensities (range: 5–152 μmole photons s?1 m?2) and combined 454‐pyrosequencing and enzymatic activity assays to evaluate the effects of light on biofilm structure and function. We observed a shift in bacterial community composition along the light gradient, whereas there was no apparent change in alpha diversity. Multifunctionality, based on extracellular enzymes, was highest under high light conditions and decoupled from bacterial diversity. Phenol oxidase activity, involved in the degradation of polyphenolic compounds, was twice as high on average under the lowest compared with the highest light condition. This suggests a shift in reliance of microbial heterotrophs on biofilm phototroph‐derived organic matter under high light availability to more complex organic matter under low light. Furthermore, extracellular enzyme activities correlated with nutrient cycling and community respiration, supporting the link between biofilm structure–function and biogeochemical fluxes in streams. Our findings demonstrate that changes in light availability are likely to have significant impacts on biofilm structure and function, potentially affecting stream ecosystem processes. 相似文献
8.
Understorey productivity in temperate grassy woodland responds to soil water availability but not to elevated [CO2]
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Luke Collins Ross A. Bradstock Victor Resco de Dios Remko A. Duursma Sabrina Velasco Matthias M. Boer 《Global Change Biology》2018,24(6):2366-2376
Rising atmospheric [CO2] and associated climate change are expected to modify primary productivity across a range of ecosystems globally. Increasing aridity is predicted to reduce grassland productivity, although rising [CO2] and associated increases in plant water use efficiency may partially offset the effect of drying on growth. Difficulties arise in predicting the direction and magnitude of future changes in ecosystem productivity, due to limited field experimentation investigating climate and CO2 interactions. We use repeat near‐surface digital photography to quantify the effects of water availability and experimentally manipulated elevated [CO2] (eCO2) on understorey live foliage cover and biomass over three growing seasons in a temperate grassy woodland in south‐eastern Australia. We hypothesised that (i) understorey herbaceous productivity is dependent upon soil water availability, and (ii) that eCO2 will increase productivity, with greatest stimulation occurring under conditions of low water availability. Soil volumetric water content (VWC) determined foliage cover and growth rates over the length of the growing season (August to March), with low VWC (<0.1 m3 m?3) reducing productivity. However, eCO2 did not increase herbaceous cover and biomass over the duration of the experiment, or mitigate the effects of low water availability on understorey growth rates and cover. Our findings suggest that projected increases in aridity in temperate woodlands are likely to lead to reduced understorey productivity, with little scope for eCO2 to offset these changes. 相似文献
9.
Collin J. Peterson Nicholas J. DeCesare Teagan A. Hayes Chad J. Bishop Michael S. Mitchell 《The Journal of wildlife management》2022,86(1):e22135
Ungulate behavior is often characterized as balancing selection for forage and avoidance of predation risk. Within partially migratory ungulate populations, this balancing occurs across multiple spatial scales, potentially resulting in different exposure to costs and benefits between migrants and residents. We assessed how availability and selection of forage and risk from predators varied between summer ranges of migrant and resident mule deer (Odocoileus hemionus; a species in which individual migratory strategies are generally fixed for life) in 3 study areas in western Montana, USA, during summers 2017–2019. We hypothesized that mule deer would face a tradeoff between selecting forage and avoiding predation risk, and that migration and residency would pose contrasting availability of forage and risk at a broad (summer range) spatial scale. We hypothesized deer exposed to lower forage at a given spatial scale would compensate for reduced availability by increasing selection of forage at the cost of reduced avoidance of predators, a mechanism whereby migrants and residents could potentially achieve similar exposure to forage despite disparate availability. We compared the availability of forage (kcal/m2) and predation risk from wolves (Canis lupus) and mountain lions (Puma concolor) between summer ranges of each migratory strategy, then assessed how selection for those factors at the home range (second order) and within-home range (third order) scales varied using resource selection functions (RSFs). As forage availability increased among mule deer summer ranges and individual home ranges, selection for forage decreased at the second-order (P = 0.052) and third-order (P = 0.081) scales, respectively, but avoidance of predators varied weakly. In 1 study area, summer range of residents contained lower forage and higher risk than summer range of migrants, but residents compensated for this disadvantage through stronger selection of forage and avoidance of risk at finer spatial scales. In the other 2 study areas, summer range of migrants contained lower forage and higher risk than residents, but migrants did not compensate through stronger selection for beneficial resources. The majority of mule deer in our study system were migratory, though the benefits of migration were unclear, suggesting partial migration may persist in populations even when exposure to forage and predation risk appears unequal between strategies. 相似文献
10.
11.
Background
Home range is defined as the extent and location of the area covered annually by a wild animal in its natural habitat. Studies of African and Indian elephants in landscapes of largely open habitats have indicated that the sizes of the home range are determined not only by the food supplies and seasonal changes, but also by numerous other factors including availability of water sources, habitat loss and the existence of man-made barriers. The home range size for the Bornean elephant had never been investigated before.Methodology/Principal Findings
The first satellite tracking program to investigate the movement of wild Bornean elephants in Sabah was initiated in 2005. Five adult female elephants were immobilized and neck collars were fitted with tracking devices. The sizes of their home range and movement patterns were determined using location data gathered from a satellite tracking system and analyzed by using the Minimum Convex Polygon and Harmonic Mean methods. Home range size was estimated to be 250 to 400 km2 in a non-fragmented forest and 600 km2 in a fragmented forest. The ranging behavior was influenced by the size of the natural forest habitat and the availability of permanent water sources. The movement pattern was influenced by human disturbance and the need to move from one feeding site to another.Conclusions/Significance
Home range and movement rate were influenced by the degree of habitat fragmentation. Once habitat was cleared or converted, the availability of food plants and water sources were reduced, forcing the elephants to travel to adjacent forest areas. Therefore movement rate in fragmented forest was higher than in the non-fragmented forest. Finally, in fragmented habitat human and elephant conflict occurrences were likely to be higher, due to increased movement bringing elephants into contact more often with humans. 相似文献12.
Ronald D. Zweig 《Hydrobiologia》1989,171(1):11-21
Intensive polyculture of blue tilapia, Oreochromis aureus, and common carp, Cyprinus carpio was conducted to determine their growth capacity and the accompanying water quality transitions in a 376 m2 (207 m3) fish pond without aeration or water exchange. A total of 485 fingerlings (290 tilapia and 195 carp) averaging 72 g each (total 35 kg) was stocked and fed commercial floating pellets (36% protein-6%-N) at the approximate daily rate of 3% of the fish biomass six days each week. The total net fish growth was 159.4 kg (4.2 t ha–1) with an average growth of 199.5 g per fish through the 96 days feeding period — 6 June to 7 September 1984. The s conversion ratio for the commercial feed was 1.3.Physiochemical patterns in the pond water were directly related to the rise and fall of turbidity through the course of the production trial. During one period of low turbidity, a biological inversion was evident with pH and dissolved oxygen measured at higher levels near the pond bottom and increasingly lower toward the surface. It is postulated that settled phytoplankton formed a photosynthetically-active algal mat on the pond bottom. The implications for potential fish kills can be significant. 相似文献
13.
Intraguild (IG) predation is an important factor influencing community structure, yet factors allowing coexistence of IG predator
and IG prey are not well understood. The existence of spatial refuges for IG prey has recently been noted for their importance
in allowing coexistence. However, reduction in basal prey availability might lead IG prey to leave spatial refuges for greater
access to prey, leading to increased IG predation and fewer opportunities for coexistence. We determined how the availability
of prey affected space-use patterns of bobcats (Lynx rufus, IG prey) in relation to coyote space-use patterns (Canis latrans, IG predators). We located animals from fall 2007 to spring 2009 and estimated bobcat home ranges and core areas seasonally.
For each bobcat relocation, we determined intensity of coyote use, distance to water, small mammal biomass, and mean small
mammal biomass of the home range during the season the location was collected. We built generalized linear mixed models and
used Akaike Information Criteria to determine which factors best predicted bobcat space use. Coyote intensity was a primary
determinant of bobcat core area location. In bobcat home ranges with abundant prey, core areas occurred where coyote use was
low, but shifted to areas intensively used by coyotes when prey declined. High spatial variability in basal prey abundance
allowed some bobcats to avoid coyotes while at the same time others were forced into more risky areas. Our results suggest
that multiple behavioral strategies associated with spatial variation in basal prey abundance likely allow IG prey and IG
predators to coexist. 相似文献
14.
Despite the fact that the vast majority of natural prey items are dispersed in a non-random manner, few studies of frequency-dependent
selective predation have explicitly examined the effect of prey dispersion on selectivity. We examined the effect of prey
dispersion on the direction and strength of frequency-dependent selection by wild birds feeding on artificial prey (green
or brown pastry baits). In a series of four experimental manipulations, we tested for the occurrence of frequency dependence
with two different dispersion patterns (random or clumped). Manipulations were carried out at one of two absolute densities
(25 prey m−2 or 100 prey m−2), and were repeated at different sites in Southampton, England and Aljarafe, Spain. Our results suggest that prey dispersion
has no effect on either frequency-dependent or -independent preferences. One possible explanation for this is that the birds
had virtually complete information about prey frequencies at the relatively high densities used and based their preferences
on their overall perception of availability. However, we cannot rule out the possibility that dispersion may influence selectivity
when prey are cryptic or available at lower absolute densities. Although there was no effect of dispersion, frequency-dependent
selection was, overall, significantly anti-apostatic (i.e. rare baits were more preferred than common baits). This anti-apostatic
effect was stronger in Southampton than Aljarafe and stronger at 100 prey m−2 than 25 prey m−2. The differences in the strength of selection between the two locations was interpreted in terms of (i) whether the avian
predators foraged in flocks or not, and (ii) the number of different species present (and, consequently, the variation in
preference among individual birds).
Received: 21 December 1996 / Accepted: 26 February 1997 相似文献
15.
We tested the hypothesis that small rock-enclosed geologic refuges have an important role in maintaining grazing-sensitive
species in grassland with a long history of intense grazing. The study was carried out in Mediterranean grassland in a basalt
landscape in northern Israel. Community composition was compared in 63 sites between samples of 1 m2 quadrats in two microhabitats: (1) rock-enclosed, presumed “refuges” and (2) rock-adjacent, “near refuges” but just outside
them, accessible to cattle grazing. Median refuge area was 2.75 m2, median rock height and diameter around refuges were 1.10 m and 1.50 m. Median height of residual dry herbage was 1.41 m
in refuges, compared to 0.38 m outside, indicating the difference in grazing intensity. Species richness at three scales (quadrat,
site, all sites) was significantly greater in the near-refuge than in the refuge habitat. In the latter, many annuals were
excluded by dominance of tall perennials. Twelve species (of 103) had significantly higher cover in refuges, including tall
perennial grasses, tall annuals, climbers, and a shrub. A total of 53 species with a strong significant negative response
to refuges were mostly small and medium height annuals. The intermediate group of 38 species with weak or non-significant
responses to refuges included, among others, dominant tall grasses that were abundant both in refuges and just outside them.
The latter, as well as most refuge-positive species had shown a positive response to protection in exclosures. The results
support the hypothesis that small rock-enclosed habitats—more so than artificial exclosures—are effective grazing refuges
for rare, grazing-susceptible species. The contribution of refuges to species richness at the landscape scale is much greater
than their proportion of the area. Dispersion from refuges maintains small populations of rare species near refuges and can
initiate expansion into the landscape when grazing pressure is lowered. 相似文献
16.
1. The diel foraging periodicities of two grazing mayfly (Ephemeroptera) nymphs, Heptagenia dalecarlica and Baetis rhodani, under variable fish (European minnow) predation risk were examined in a series of laboratory experiments. 2. Heptagenia dalecarlica were almost exclusively nocturnal in their use of feeding areas on stone tops. There was a sharp increase in the proportion of nymphs out of refuge at nightfall, both in the control and fish-odour treatments. In a treatment with freely moving fish, H. dalecarlica decreased their activity during both the day and night. In feeding trials with three freely foraging minnows, nymphs were completely safe when they had access to refuges beneath stones, whereas almost half the nymphs were consumed when no refuges were available. 3. Baetis rhodani nymphs reduced their use of stone tops when exposed to four caged minnows or a freely moving fish, but this occurred both day and night. In feeding trials, B. rhodani were captured only while in the water column, and their mortality risk was independent of refuge availability. 4. It is suggested that because H. dalecarlica lack efficient post-encounter defences, they must rely on pre-encounter mechanisms to reduce the threat of fish predation. It appears that in order to dwell sympatrically with fish, H. dalecarlica have evolved a coexistence by hiding strategy. In contrast, Baetis are vulnerable to fish attacks only if they enter drift in daylight, and are thus able to remain on stone tops both during the day and at night. 相似文献
17.
Bluegill growth as modified by plant density: an exploration of underlying mechanisms 总被引:1,自引:0,他引:1
Summary Bluegill (Lepomis macrochira) growth varies inconsistently with plant density. In laboratory and field experiments, we explored mechanisms underlying bluegill growth as a function of plant and invertebrate density. In the laboratory, bluegills captured more chironomids (Chironomus riparius) than damselflies (Enallagma spp. and Ischnura spp.), but energy intake per time spent searching did not differ between damselfly and chironomid treatments. From laboratory data, we described prey encounter rates as functions of plant and invertebrate density. In Clark Lake, Ohio, we created 0.05-ha mesocosms of inshore vegetation to generate macrophyte densities of 125, 270, and 385 stems/m2 of Potamogeton and Ceratophyllum and added 46-mm bluegill (1/m2). In these mesocosms, invertebrate density increased as a function of macrophyte density. Combining this function with encounter rate functions derived from laboratory data, we predicted that bluegill growth should peak at a high macrophyte density, greater than 1000 stems/m2, even though growth should change only slightly beyond 100 stems/m2. Consistent with our predictions, bluegills did not grow differentially, nor did their use of different prey taxa differ, across macrophyte densities in the field. Bluegills preferred chironomid pupae, which were relatively few in numbers but vulnerable to predation, whereas more cryptic, chironomid larvae, which were associated with vegetation but were relatively abundant, were eaten as encountered. Bluegills avoided physid snails, which were abundant. Contrary to previous work, vegetation did not influence growth or diet of bluegill beyond relatively low densities owing to the interaction between capture probabilities and macroinvertebrate densities.The unit is sponsored jointly by the United States Fish and Wildlife Service, Ohio Department of Natural Resources, The Ohio State University, and The Wildlife Management Institute 相似文献
18.
Jos Martín Pilar Lpez William E. Cooper 《Ethology : formerly Zeitschrift fur Tierpsychologie》2003,109(1):77-87
Prey often respond to predator presence by increasing their use of refuges, but because this strategy may be costly, the decision regarding when to come out from a refuge should be optimized. The loss of foraging opportunities may be one of the main costs when safer microhabitats (i.e. refuges) are also the poorest in terms of their foraging profitability. We present the results of an experimental field study to test whether emergence times from a refuge of the Iberian rock lizard, Lacerta monticola, vary as a function of expected foraging opportunities and level of satiation of the lizard. As predicted, short‐term fluctuations in availability of food influenced emergence times; when a lizard had just detected some food in the recent past, emergence times decreased greatly, because the loss of opportunities for foraging increased costs of refuge use. Furthermore, the characteristics and success of the encounter with food, nutritional state of lizards, and the added possibility of capturing new food items influenced the duration of hiding times. Therefore, foraging requirements and avoidance of predators may be conflicting demands that L. monticola lizards balance by modifying the duration of time spent in refuges. 相似文献
19.
The home range ofTakydromus tachydromoides was studied in a grassland area from April 1977 to November 1978. The mean size of home range did not differ markedly between
sexes; 136.5 m2 for males and 130.8 m2 for females. Home ranges of adults overlapped greatly in each sex, and the lizard was considered to be non-territorial. Individuals
showed return movement to a definite area (sleeping site) within the home range, and the home range did not shift within a
year or between years. Characteristics of the home range of this grassland-inhabiting lizard were discussed in relation to
resource abundance and predation pressure. 相似文献
20.
Ranging of <Emphasis Type="Italic">Rhinopithecus bieti</Emphasis> in the Samage Forest,China. I. Characteristics of Range Use 总被引:1,自引:1,他引:0
Cyril C. Grueter Dayong Li Carel P. van Schaik Baoping Ren Yongcheng Long Fuwen Wei 《International journal of primatology》2008,29(5):1121-1145
We quantified the home range and explored the style of ranging of black-and-white snub-nosed monkeys (Rhinopithecus bieti) in the subtropical-temperate montane Samage Forest (part of Baimaxueshan Nature Reserve) in the vicinity of Gehuaqing. Over
14.5 mo, we took positional records of the study band via a GPS receiver at 30-min intervals, and found that they covered
an area of 32 km2. Over a 10-yr period, the group even ranged in an area of 56 km2, which is among the largest home range estimates for any primate. The large home range was probably due to the combined effects
of large group size (N > 400) and forest heterogeneity, with seasonally food-rich areas interspersed with less valuable areas. The subjects did
not use their home range uniformly: 29% of the grid cells had more location records than expected based on a uniform distribution,
thus representing a core area, albeit a disjunct one. A continuous 1-mo group follow in the fall revealed that the band traveled
on average 1.62 km/d and that days of concentrated use of a particular forest block were followed by more extensive marches.
Neither climate nor human disturbance parameters correlate significantly with monthly estimates of the group’s home range
size. Even though there is no significant correlation between temporal availability of plant phenophases and range size, our
observations implicate temporal and spatial availability of food as a determinant of home range use of the focal group. Winter,
spring, and summer home ranges are equally large: 18.2, 17.8, and 18.6 km2, respectively. Home range decreased markedly in fall (9.3 km2), probably because the band obtained sufficient food resources (fruit) in a smaller area. The large winter range is best
attributed to the exploitation of dispersed clumped patches of mature fruits.
Cyril C. Grueter and∙Dayong Li contributed equally to the paper. 相似文献