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41.
We examined the effects of extreme seasonality on the activity budget and diet of wild chacma baboons with access to a high‐quality, human‐derived food source. The Cape Peninsula of South Africa is unusual among nonhuman primate habitats due to its seasonal extremes in day length and climate. Winter days are markedly shorter and colder than summer days but have higher rainfall and higher primary production of annually flowering plants. This combination of fewer daylight hours but higher rainfall is substantially different from the ecological constraints faced by both equatorial baboon populations and those living in temperate climates with summer rainfall. We sought to understand how these seasonal differences affect time budgets of food‐enhanced troops in comparison to both other food‐enhanced troops and wild foraging troops at similar latitudes. Our results revealed significant seasonal differences in activity budget and diet, a finding that contrasts with other baboon populations with access to high‐return anthropogenic foods. Similar to nonprovisioned troops at similar latitudes, troop members spent more time feeding, socializing, and traveling during the long summer days compared to the short winter days, and proportionately more time feeding and less time resting in summer compared to winter. Summer diets consisted mainly of fynbos and nonindigenous foods, whereas winter diets were dominated by annually flowering plants (mainly grasses) and ostrich pellets raided from a nearby ostrich farm. In this case, food enhancement may have effectively exaggerated seasonal differences in activity budgets by providing access to a high‐return food (ostrich pellets) that was spatially and temporally coincident with abundant winter fallback foods (grasses). The frequent use of both alien vegetation and high‐return, human‐derived foods highlights the dietary flexibility of baboons as a key element of their overall success in rapidly transforming environments such as the South African Cape Peninsula. Am. J. Primatol. 72:104–112, 2010. © 2009 Wiley‐Liss, Inc. 相似文献
42.
Zachary S. Ladin Paul M. Castelli Scott R. Mcwilliams Christopher K. Williams 《The Journal of wildlife management》2011,75(2):273-282
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
43.
The transformation of natural land for agricultural and urban use has displaced baboons from large parts of their historical distribution. Abundant resources within transformed areas, however, continue to attract baboons back into these human-dominated areas resulting in chronic levels of conflict throughout much of Africa. In the city of Cape Town, chacma baboons (Papio ursinus) have been raiding human-derived foods for over 200 years. In the last 20 years, the management of this conflict has shifted from predominantly lethal to nonlethal methods. In this study, we assess the success of field rangers to deter baboons from urban areas and investigate whether such management affects the diet and activity patterns of baboons. We opportunistically sampled baboon behavior and movement when field rangers were temporarily absent from managed troops in 2008. We also compared the intensity of baboon management by comparing one troop on days when the field rangers aggressively herded the troop away from the urban edge versus passively monitored them in 2004/2005. Our results reveal that when field rangers were absent, the two troops spent 70% and 80% of their time within the urban edge compared to 3% and 19% when they were present. Both troops also consumed more human-derived foods when field rangers were absent. There was no significant change in the activity budget or daily distance traveled for either troop with and without field rangers. The intensity of herding did have an impact on baboon activity and high levels of herding significantly reduced time spent feeding and increased time spent traveling, socializing, and resting. Habitat use and dietary composition did not differ between high- and low-herding days. Our results suggest that field rangers are a successful nonlethal method for reducing spatial overlap between baboons and urban areas but that intensive, unsystematic herding of the troop does have measurable impacts on behavior and should be prevented. 相似文献
44.
An observational study of chamois behavior during the rut was conducted at the Los Angeles Zoo. The herd consisted of an adult male, two adult females, two subadult females, and two kids (1.1). During the 13-week study, observers collected scan data on all animals and recorded all occurrences of selected social behaviors during interactions which involved the adult male. Scan observations showed that open areas of the enclosure close to the public were the least preferred, and areas with good rest places were used most. Overall the herd spent 73% of their time stationary, 13% foraging/feeding, 6% moving, and less than 5% each in object investigation, maintenance, play, and social behavior. The adult male rested and fed less, and stood vigilant and engaged in social behavior more frequently than the others. Nearest neighbor data showed clear patterns of kin association beyond the mother-last kid bond. The adult male interacted most often with the regular keepers, the subordinate female and the oldest subadult female. Interactions with the females consisted mostly of herding and sexual behaviors, while those with keepers were almost exclusively competitive/aggressive. While most findings paralleled those from studies of wild chamois, no study has previously reported long-lasting associations among kin. 相似文献
45.
ABSTRACT In an effort to reduce goose depredation at a traditional spring migratory stopover site, private landowners implemented a coordinated hazing plan to scare Aleutian cackling geese (Branta hutchinsii leucopareia) from private lands to adjacent public pastures that were cultivated and set aside specifically for geese. Coincidentally, some Aleutian geese began using a new stopover site 150 km farther south in their spring migratory range; numbers at the new site continue to increase. We tested the idea that when their ability to acquire resources deteriorates geese are likely to seek improved foraging conditions, especially during spring migration when individuals strive to maximize nutrient stores and minimize energy expenditure. We quantified measures of goose foraging performance in traditional and new spring staging sites by calculating foraging opportunity, foraging effort, body condition, and daily energy expenditure. Geese staging at the site with higher levels of human disturbance had less foraging opportunity and, despite increased foraging effort and more nutritious food-plants at the site, birds there experienced an elevated energy expenditure and poorer body condition than birds at the new stopover site. Reduced foraging time and increased energy expenditure at the traditional spring staging site may have triggered the colonization process. Suitability assessment of habitat for migratory geese should include measures of foraging opportunity, disturbance risks, and daily energy expenditure in addition to quantity and quality of foods. 相似文献
46.
Question: Grasses often resprout from surviving belowground buds following a fire in which aboveground matter is consumed. We used a soil heat and water transport model to present a general method for determining the potential mortality of rhizome buds due to fire for three tallgrass species (Andropogon gerardii, Sorghastrum nutans, and Panicum virgatum). Methods: Soil heating was described by physical processes that include heat conduction through the soil and heating and evaporation of soil water. We considered the following factors: soil moisture, texture, mineral thermal conductivity, maximum surface temperature, and fire residence time. Simulated soil temperature profiles were combined with measured belowground bud distributions to determine the proportion of buds expected to be heated to lethal temperatures under various conditions. Location: Wisconsin, USA. Results: Lethal temperatures for buds do not occur below ~2 cm, and at least 30% of rhizome buds remain below lethal temperatures, even under extreme conditions. Conclusions: The model explains the possible mechanisms for grass belowground rhizome bud survival in fires. Changes in fire and soil conditions do not notably impact soil temperatures and rhizome bud survival. 相似文献
47.
Understanding historical patterns of soil phosphorus (P) accumulation is critical to management of water quality across agricultural
landscapes. To address the effects of long-term agricultural P management on soil P accumulation in the Saint Lawrence River
sub-basin (574,000 km2), we calculated cropland P budgets at decadal intervals from 1901 to 2001 for the sub-basin and its tributary watersheds.
Agricultural census data were used to estimate P inputs in the form of fertilizer and manure, and outputs (P removed in harvested
crops). The resulting balances indicate the potential magnitude of P accumulation in cropland soils. Cropland P surpluses
occurred in the sub-basin in each decade of the past century, with the rate of accumulation increasing after 1951 due to more
widespread use of P fertilizers and manure. The largest annual P surplus occurred in 1981 (42,000 Mg y−1), followed by a decline in the rate of accumulation to almost half that level by 2001 (24,850 Mg y−1) as a result of improved management of agricultural P. Comparison of the cumulative P surpluses estimated for the entire
20th century with measured soil P data indicates a strong linear relationship between these watershed P budgets and the average
soil P content across the sub-basin (R
2 = 0.712, P < 0.0001). These results support the view that historical land management can have important ecological legacies. 相似文献
48.
The effect of energy budget on risk-sensitive foraging was assessedin a
laboratory experiment using starlings (Sturnus vulgaris).Subjects chose
between two options offering the same mean amountof food per trial, but
differing in variance: a "fixed" optiongave 5 units food in every
trial, and a "variable" option gave2 or 11 units food with
probabilities 2/3 and 1/3, respectively.We manipulated energy budgets by
controlling the cumulativeamount of food received by each bird at the end of
a day. Inone treatment (positive budget) individuals were allowed toeat at
the level of their own ad-libitum daily consumption,while for the other
(negative budget), food was rationed toprovoke a steady drop in body weight
during the experimentalperiod. No subject was allowed to drop below 80% of
its ad libitumbody weight. Contrary to predictions from the "energy
budgetrule" and contrary to reported results of some other studies,
starlingssignificantly preferred the "fixed" option irrespective
of energybudget conditions. Our results support the view that persistentrisk
aversion for food amounts and risk proneness for food delaysare the norm, and
shifts in risk attitude according to energybudget are exceptions. Several
algorithms, which may have evolvedto maximize energetic pay off between
variable food sources,can produce this trend as a side effect. We discuss two
of thesealgorithms: (1) maximization of local (per trial) rate as opposedto
global rate of gains, with longer handling time for largerrewards, and (2)
choosing larger rewards and smaller delayssubject to Weber's law in the
memory for the parameters of eachfood supply. 相似文献
49.
笼养大紫胸鹦鹉的活动时间分配 总被引:22,自引:0,他引:22
研究了笼养大紫胸鹦鹉的行为活动和时间分配。结果表明:笼养大紫胸鹦鹉一天中除静栖外,其余各行为所占时间比例在中午较小,而在早晚较大;在一年中不同月份间各种行为活动所占时间比例也有变化,呈明显的年周期和日节律;节律变化与日出、日落时间、季节、温度等变化有关。大紫胸鹦鹉各种行为活动所占比例分别为静栖45.55%、身体护理16.66%、取食14.51%、运动10.60%、在巢8.98%、繁殖2.55%、社 相似文献
50.
Ecology and management of moorland pools: balancing acidification and eutrophication 总被引:3,自引:3,他引:0
Moorland pools originally are shallow, often hydrologically isolated, soft-water bodies, with a low productivity. Some thousands
of moorland pools originated from the late Pleistocene onwards in the heathland landscape in The Netherlands and adjacent
areas, where soils have a poor buffering capacity. As the pools are largely fed by atmospheric precipitation, they are very
vulnerable to changes in the environment, e.g. eutrophication and acidification.
Moorland pools are exposed to very high rates of wet atmospheric deposition: 44–50 mmol m−2 yr−1 sulphate and 84–103 mmol m −2 yr−1 ammonium. Mass budgets indicate that 20–70% of the input of sulphate by precipitation is reduced, 40–100% of the ammonium
input escapes to the air or sediments, apparently due to nitrification, and 90–100% of incoming nitrate disappears. The production
of alkalinity ranges from 12 to 52 meq m−2 yr−1. The efficiency of these processes augments with pH-values of surface water increasing from 4.1 to 5.4. The accumulation
of reduced sulphur compounds in the sediments is a threat in extremely dry summers, when desiccation causes oxydation of these
compounds, resulting in very low pH-values (≤ 3.7).
Acidification by acid atmospheric deposition and eutrophication by agricultural acidification are the main threats to the
moorland pool ecosystems and affect the species composition of assemblages of aquatic macrophytes, desmids, diatoms, macrofauna,
fishes and amphibians, as has been shown by comparison of old and recent records on their distribution and paleolimnological
methods. Afforestation exacerbates acidification and also reduces wind dynamics. Particularly the decrease of isoetids and
desmids by both processes indicate the biological impoverishment of the pools.
Reductions of (potential) acid atmospheric deposition to less than 40 mmol m−2 yr and of ammonia to less than 30 mmol m−2 yr are necessary for recovery of the moorland pools. Methods for the addition of buffering material to a number of moorland
pools, to counteract acidification until these deposition rates have lowered sufficiently, are given, as well as other methods
for restoring the biological quality of moorland pools. 相似文献