White-tailed deer movement and distribution about surface coal mines in West Virginia,USA

Deer movements around surface coal mines were investigated in Preston Country, West Virginia, USA. Seventy-two deer crossings were counted on 29 surface mines with only 8% found on highwalls with more than 20% rock or stone. Thus, although slope was important, the percentage of dirt on the highwall determined use as a crossing location for deer. The average distance between all deer crossing was 209.7 m but the distance between the end of the highwall and the nearest highwall crossing was 248.7 m indicating reluctance of deer to cross mines when they could walk around them. Winter snow track counts showed fewer deer within 90 m of the top edge of the highwall. Four land bridges traversed the highwall and were heavily utilized by deer, especially in March, April, May, October and November. The surface mine bench was used as a fawn bedding area, but little feeding occurred on this portion of the mine.     

Effect of sheep grazing and fire on sage grouse populations in southeastern Idaho

This paper describes the development, evaluation, and use of a model that simulates the effect of grazing and fire on temporal and spatial aspects of sagebrush community vegetation and sage grouse population dynamics. The model is represented mathematically as a discrete-time, stochastic compartment model based on difference equations with a time interval of 1 week. In the model, sheep graze through sage grouse breeding habitat during spring and fall, and different portions of the area can burn at different frequencies, creating a habitat mosaic of burned and unburned areas.The model was evaluated by examining predictions of (1) growth of sagebrush canopy cover after fire, (2) seasonal dynamics of grass and forb biomass under historical environmental conditions, and (3) sage grouse population dynamics associated with selected sagebrush canopy covers. Simulated changes in sagebrush canopy cover following fire correspond well with qualitative reports of long-term trends, simulated seasonal dynamics of herbaceous biomass correspond well with field data, and simulated responses of sage grouse population size and age structure to changing sagebrush canopy cover correspond well to qualitative field observations.Simulation results suggest that large fires occurring at high frequencies may lead to the extinction of sage grouse populations, whereas fires occurring at low frequencies may benefit sage grouse if burned areas are small and sheep grazing is absent. Sheep grazing may contribute to sage grouse population decline, but is unlikely to cause extinction under fire regimes that are favorable to sage grouse.     

Effects of costs and benefits of brood care on filial cannibalism in the sand goby

This study tested experimentally whether clutch size and the cost of care affect filial cannibalism in the sand goby, Pomatoschistus minutus. Evolutionary models of filial cannibalism suggest that egg eating has evolved as a way for the male parent to prolong his breeding season. These models assume that eggs function as an alternative energy source for the constrained parent. I manipulated clutch size by allowing males to mate with either one or two females, representing a small and a large clutch, respectively. The addition of a small male shore crab, a common egg predator, increased the cost of care. I quantified fat reserves as a measure of the condition of guarding males. Males who did not build nests had lower fat reserves than males who built nests, suggesting that males with low energy reserves do not start breeding. Males with small clutches lost their nest to the crab more often than males with large clutches. Neither filial cannibalism nor the amount of eggs eaten were affected by the treatments. Males who consumed eggs had a higher fat percentage than males who did not eat eggs. The result that males with small clutches lost their nests to the crabs supports the idea that eggs are defended only if the benefit from continued care will outweigh the cost and that males therefore are sensitive to the trade-off between present and future reproductive success. Received: 15 May 1997 / Accepted after revision: 15 November 1997     

崇明岛新围垦区不同土地利用条件下的土壤呼吸研究

土地利用方式是影响温室气体减排的关键因子之一。新围垦土地因其土壤本底均一、土地利用历史简单短暂,使得评价短期土地利用对温室气体排放的影响成为可能。为此,在崇明东滩湿地新围垦区选取了本底均匀、利用历史简单的几种土地利用类型（旱田、水旱轮作农田、人工林带）,研究其土壤呼吸的变化及其与土壤环境间的关系,以期评价其各自的固碳和温室气体减排潜力。研究表明,2009年整个春季,土壤呼吸速率强度的顺序为水旱轮作[（0.30±0.08）mol.m-2.d-1]〉旱田[（0.18±0.04）mol.m-2.d-1]〉林带[（0.09±0.01）mol.m-2.d-1];春季各月份,水旱轮作田土壤呼吸速率变化波动较大,旱田较平稳,4、5月份最先达到日最高值,人工林带最为平稳,且始终具有较低的呼吸强度;旱田土壤呼吸速率均不能简单用土壤5 cm处温度及湿度进行解释,林带与水旱轮作田土壤呼吸速率与土壤5 cm处温度显著相关（P〈0.05）;整个春季,林带土壤呼吸与5 cm处温度及湿度均显著相关,其中与温度极显著相关（P=0.01）,水旱轮作田与旱田的土壤呼吸速率与两者均不相关。     

Effects of foundress number on brood raids and queen survival in the fire ant Solenopsis invicta

In several ant species, colonies are founded by small groups of queens (pleometrosis), which coexist until the first workers eclose, after which all but one queen is killed. It has been hypothesized that, by producing a larger cohort of workers, cooperating queens may increase colony success during brood raids, a form of competition in which brood and workers from losing nests are absorbed into winning colonies. To test whether this benefit is sufficient to favor pleometrosis, newly mated queens of the fire ant Solenopsis invicta were assembled in groups of one, two, three, or four, reared in the laboratory until the first workers eclosed, then planted in the field in replicated assemblages. The proportion of colonies engaging in brood raids increased with average foundress number per nest and with colony density but was unaffected by variance in foundress number among interacting colonies. Within mixed assemblages of single-queen and multiple-queen colonies, queen number had no effect on the likelihood of engaging in raids or the probability of nest survival through the brood raiding period. However, following nearly 30% of raids, queens moved to new nests and displaced the resident queens. When queen relocation and subsequent mortality were accounted for, it was found that the survival of queens from four-queen groups was substantially higher than that of solitary queens. By contrast, the survival of queens from two-queen colonies was no greater than that of solitary queens. These results show that the competitive advantages of multiple-queen colonies are sufficient to counterbalance the increased mortality of queens within groups only when the number of foundresses is greater than two and when colonies are founded at high density. When colonies lose brood raids, the workers appear to abandon their mothers to join surviving colonies. However, in laboratory experiments, queens attempting to enter foreign nests were significantly more likely to displace the resident queen if their own daughters were present within the invaded nest. Thus, workers may be able to bias the probability that their mother rejoins them and displaces competing queens.     

The effect of helpers on artificially increased brood size in sociable weavers (Philetairus socius)

In cooperatively breeding birds, the presence of helpers is expected to increase the reproductive success of the breeding pair. However, some studies fail to find this effect. A positive effect of helpers may be restricted to cases in which a breeding pair has a poor likelihood of raising the entire brood on its own, as would be the case under stressful environmental conditions or with enlarged brood sizes. We conducted brood size manipulations in a cooperative breeder, the sociable weaver, Philetairus socius, to investigate the relationship between the difficulty of raising nestlings and the effort and impact of helpers. Overall, sociable weavers did not work harder to raise the enlarged broods. However, the presence of helpers significantly increased the feeding rates at enlarged nests, but not controls. This was insufficient to prevent generalised brood reduction in enlarged broods, whether attended by pairs alone or with helpers. Nonetheless, the presence of helpers was associated with decreased nestling mortality and an increase in the numbers of young fledged. Our results suggest that groups are better able to respond to the needs of enlarged broods than pairs alone and that the presence of helpers has a beneficial effect on overall reproductive success.Communicated by J. Dickinson     

The effects of parasites on male ornaments and female choice in the lek-breeding black grouse (Tetrao tetrix)

Summary We describe the results of two studies of parasitic infection in the black grouse (Tetrao tetrix). The first deals with our own observations of lekking black grouse in which the parasite levels of two blood parasites, the protozoan Leucocytozoon lovati and microfilaria, probably produced by a nematode worm Splendidofilaria tuvensis, were scored. We also obtained measures of age, survival, number of copulations, body mass and length of the ornamental tail feathers (the lyre) of the lekking males. The second study analysed the data from Lund (1954) which involved eight gut parasites obtained from birds which were killed. In the first study we found higher levels of infection of Leucocytozoon in adults relative to young birds. Parasites had no effect on male survival and there was no correlation in infection between the two types of parasites. Birds infected with microfilaria had shorter tail ornaments. There was no relationship between parasitic infection and mating success. However, the data indicated that such a trend indeed may exist for Leucocytozoon and the most successful males on the leks were less often infected by Leucocytozoon than other males. Results of the second study showed a negative relationship between parasite load (a combined measure of all parasites) and both ornamental tail feather length and body mass. These observations are compatible with, but not conclusive evidence for, the hypothesis of Hamilton and Zuk (1982) on the evolution of secondary sexual characters, where females choose to mate with genetically resistant males which show their resistance by expressing larger and more showy secondary sexual characters. Alternative explanations for the observed patterns are: females avoid infected males for some immediate benefit; and/or parasite loads are indicators of general stress rather than genetical resistance. Under the latter hypothesis females could mate with more vigorous males for reasons unrelated to parasite resistance.     

The effect of conspecifics on habitat selection in territorial species

Summary Despite widespread interest in habitat selection, many of the assumptions about how territorial animals choose habitats have not been tested. This study of juvenile Anolis aeneus lizards focuses on the relationship between the number of previous settlers in a habitat and the subsequent behavior of new arrivals at that habitat. Clearings containing the types of microhabitat preferred by juveniles were established in the field, several juvenile residents were allowed to establish territories in enclosures in the center of each clearing, and then naturally occurring immigrants were allowed access to the empty microhabitat surrounding the enclosures. Arrival rates and the probability of settlement were monitored on a daily basis from the day the first juveniles arrived until several days after the last juvenile had settled (=saturation). In each of seven trials, arrival rates were comparable early and late in the settlement process, and were unrelated to the degree of habitat saturation. Arrival rates did vary on a temporal basis, probably as a result of environmental factors affecting egg laying and hatching schedules, and habitats with high arrival rates saturated more quickly than those with lower arrival rates. All of the individuals arriving at the clearings did not settle, but settlers and non-settlers did not differ with respect to competitive ability, as measured by body size. The probability of settlement increased as settlement proceeded in each of seven trials, up to the day of saturation. These results refute the commonly held assumptions that prospective territory owners avoid entering relatively full habitats, and that they prefer to settle in relatively unsaturated habitats. The discussion considers why assumptions about the behavioral processes of habitat selection are so widely accepted, given the dearth of empirical information on the subject.     

烟气脱硫石膏对滩涂围垦土壤重金属解吸及残留形态的影响

滩涂围垦土壤是重金属等难降解污染物的主要最终归宿场所之一,其重金属的解吸将影响重金属的迁移性、生物有效性和潜在毒性,研究重金属的解吸对土壤污染评价、修复及环境容量预测至关重要.研究了烟气脱硫石膏对广州市南沙滩涂围垦土壤重金属的解吸效果,并分析了烟气脱硫石膏对重金属形态的影响.在离心管中称取20.0 g过0.25mm筛土样,加入20 mL水和不同量的烟气脱硫石膏,在室温下于恒温振荡器振荡,风干研碎后用原子吸收分光光度法测定重金属全量,并用Tessier连续提取法研究了处理前后重金属形态变化.研究结果表明,随着脱硫石膏施用量的增加,经过振荡离心后的滩涂围垦土壤中重金属质量分数先急剧下降,之后变化趋于平缓.与原土相比各重金属最大解吸率分别为:Cd 30.38%,Cu17.73%,Ni 15.00%,Zn 14.19%,Pb 9.46%,Cr 8.89%.比较处理前后重金属的形态变化,发现各重金属的可交换态解吸率均达50%以上,并且重金属碳酸盐结合态质量分数也有减少.说明烟气脱硫石膏能降低土壤对重金属的吸附,经振荡离心后能降低土壤中重金属的毒性和生物可利用性.     

Aliphatic and polycyclic aromatic hydrocarbon contamination in surface sediment of the Chitrapuzha River,South West India

Distribution (seasonal and spatial) of aliphatic and polycyclic aromatic hydrocarbons (PAHs) in surface sediments of the Chitrapuzha River, Cochin, India, was investigated using gas chromatography. Significantly high concentrations prevailed during the pre-monsoon season with the industrial zones of the river appearing to be hot spots with particularly elevated levels of the hydrocarbons. AHCs ranged between 7754 and 41,173?ng/g with an average of 25,256?ng/g, while total PAHs varied from 5046 to 33,087?ng/g. n-Alkane indices and PAH diagnostic ratios point to petroleum contamination in the sediments. The significance of PAHs in the sediments was explored using universally accepted interpretation tools. Observed levels of PAHs in sediments of Chitrapuzha are likely to cause adverse effects on biota.     

Investigations on brood protection inPsolus dubiosus (Echinodermata: Holothuroidea) from Antarctica in spring and autumn

Brood protection in the holothurianPsolus dubiosus Ludwig and Heding, 1935 was investigated in the Antarctic zone of permanent packice, an environment with an extreme seasonality in planktonic activity. Yearly reproductive cycles on the continental shelf of this area have been poorly investigated. Brooded juveniles of this species were found for the first time between the retracted tentacles of adult females at two different localities in the southeastern Weddell Sea, sampled in spring (October 1986) and autumn (February 1984). Mean lengths of the juveniles of each brooding female showed significant differences within each sample. However, there was no detectable difference in size of the juveniles between the two seasons. The results are discussed as an uncoupling of the dynamics of the early life history of these benthic invertebrates in space and time from processes in the euphotic layer of the Southern Ocean. The species investigated follows the general trend of some Antarctic invertebrates towards a non-pelagic development.     

Analytical discussions on species extinction in competitive communities due to habitat destruction

An improvement of a metapopulation model is developed and used to analyze the behaviors of abundant and extinct species in the system analytically. By approximating the direct effect rate of habitat destructions on individual species using differentiable functions, the model enables us to discuss the equilibrium and stability of the system. Special cases of the habitat destruction functions, constant, piecewise linear, exponential and periodic functions, are discussed analytically and numerically. The conditions for system stability are also given.     

Hydraulic model for multi-sources reclaimed water pipe network based on EPANET and its applications in Beijing, China

Water shortage is one of the major water related problems for many cities in the world. The planning for utilization of reclaimed water has been or would be drafted in these cities. For using the reclaimed water soundly, Beijing planned to build a large scale reclaimed water pipe networks with multi-sources. In order to support the plan, the integrated hydraulic model of planning pipe network was developed based on EPANET supported by geographic information system (GIS). The complicated pipe network was divided into four weak conjunction subzones according to the distribution of reclaimed water plants and the elevation. It could provide a better solution for the problem of overhigh pressure in several regions of the network. Through the scenarios analysis in different subzones, some of the initial diameter of pipes in the network was adjusted. At last the pipe network planning scheme of reclaimed water was proposed. The proposed planning scheme could reach the balances between reclaimed water requirements and reclaimed water supplies, and provided a scientific basis for the reclaimed water utilization in Beijing. Now the scheme had been adopted by Beijing municipal government.     

Tidal influences on the habitat use of Indo-Pacific humpback dolphins in an estuary

This paper offers the first study of diurnal variations in the use of an estuarine habitat by Indo-Pacific humpback dolphins. Passive acoustic data loggers were deployed in the Xin Huwei River Estuary, Western Taiwan, from July 2009 to December 2010, to collect biosonar clicks. Acoustic encounter rates of humpback dolphins on the riverside of the estuary changed significantly over the four tidal phases, instead of the two diurnal phases based on the recordings from 268 days. Among the tidal phases, the encounter rates were lowest during ebb tides. Additionally, circling movements associated with the hunt for epipelagic fish significantly changed in temporal and spatial presence over the four tidal phases, matching the overall pattern of encounter rate changes in the focal estuary. Our findings suggest that the occurrence pattern and habitat utilization of humpback dolphins are likely to be influenced by the tidal-driven activity of their epipelagic prey.     

Knowledge coproduction on the impact of decisions for waterbird habitat in a changing climate

Scientists, resource managers, and decision makers increasingly use knowledge coproduction to guide the stewardship of future landscapes under climate change. This process was applied in the California Central Valley (USA) to solve complex conservation problems, where managed wetlands and croplands are flooded between fall and spring to support some of the largest concentrations of shorebirds and waterfowl in the world. We coproduced scenario narratives, spatially explicit flooded waterbird habitat models, data products, and new knowledge about climate adaptation potential. We documented our coproduction process, and using the coproduced models, we determined when and where management actions make a difference and when climate overrides these actions. The outcomes of this process provide lessons learned on how to cocreate usable information and how to increase climate adaptive capacity in a highly managed landscape. Actions to restore wetlands and prioritize their water supply created habitat outcomes resilient to climate change impacts particularly in March, when habitat was most limited; land protection combined with management can increase the ecosystem's resilience to climate change; and uptake and use of this information was influenced by the roles of different stakeholders, rapidly changing water policies, discrepancies in decision-making time frames, and immediate crises of extreme drought. Although a broad stakeholder group contributed knowledge to scenario narratives and model development, to coproduce usable information, data products were tailored to a small set of decision contexts, leading to fewer stakeholder participants over time. A boundary organization convened stakeholders across a large landscape, and early adopters helped build legitimacy. Yet, broadscale use of climate adaptation knowledge depends on state and local policies, engagement with decision makers that have legislative and budgetary authority, and the capacity to fit data products to specific decision needs.     

Fish feeding on mobile benthic invertebrates: influence of spatial variability in habitat associations

Patterns of habitat association and foraging were examined for a group of tropical goatfishes (family Mullidae) that feed on mobile benthic invertebrates at Lizard Island (Great Barrier Reef). All goatfish possess barbels that disturb the substratum during feeding. Foraging methods were examined for the six most common species and used in conjunction with data on habitat associations to estimate the distribution and potential impact on the benthic invertebrate assemblage of foraging-related disturbance. Particular species exhibited broad habitat associations which differed little over two surveys (January 1989, January 1990). All species showed different preferences for the substrata they foraged. Preferences for substrata exhibited by the most common reef-associated species, Parupeneus multifasciatus, differed among locations separated by 1 km, between sites 150 m apart, and between depths (shallow and deep). Habitat preferences changed with ontogeny. Based on their habitat associations and foraging preferences, species were divided into habitat generalists and specialists. Specialists associated primarily with soft sediments. Habitat generalists, such as P. multifasciatus and P. cyclostomus, are likely to have an impact on their mobile invertebrate prey that is localised, diffuse and transitory, making any experimental analysis difficult and expensive. Habitat specialists form a guild of fishes with complementary feeding modes that efficiently exploit soft sediments and are more amenable to experimental manipulation. Experiments designed to detect the impact of foraging by these fishes must be repeated at different locations and times and must account for depth differences in foraging pressure.     

Effect of nutrient enrichment on growth of the eelgrass Zostera marina in the Chesapeake Bay,Virginia, USA

The addition of two commerical fertilizers, one 5% NH₄NO₃, 10% P₂O₅, 10% K₂O, and the other 10% NH₄NO₃, 10% P₂O₅, 10% K₂O, ahd a dramatic effect on the growth of Zostera marina in the Chesapeake Bay. There was a significant increase in the length, biomass and total number of turions of fertilized plots compared with controls during a 2 to 3 month period. Data from this short-term field experiment suggest that Z. marina beds in the Chesapeake Bay are nutrient-limited, that the grwoth form of Z. marina may be related to the sediment nutrient supply, and that Z. marina may competitively exclude Ruppia maritima by light-shading.     

Antagonistic effect of natural habitat conversion on community adjustment to climate warming in nonbreeding waterbirds

Although the impacts of climate and land-use changes on biodiversity have been widely documented, their joint effects remain poorly understood. We evaluated how nonbreeding waterbird communities adjust to climate warming along a gradient of land-use change. Using midwinter waterbird counts (132 species) at 164 major nonbreeding sites in 22 Mediterranean countries, we assessed the changes in species composition from 1991 to 2010, relative to thermal niche position and breadth, in response to regional and local winter temperature anomalies and conversion of natural habitats. We observed a low-level, nonsignificant community adjustment to the temperature increase where natural habitat conversion occurred. At the sites affected by natural habitat conversion, the relative increase of warm-dwelling species in response to climate warming was 6 times lower and the relative species decline was 3 times higher than in the sites without natural habitat conversion. We found no evidence of community adjustment to climate warming when natural habitat conversion was >5% over 15 years. This strong negative effect suggests an antagonistic interaction between climate warming and habitat change. These results underline the importance of habitat conservation in community adjustment to climate warming.     

Effects of predators on sea urchin density and habitat use in a southern California kelp forest

Grazing sea urchins can reduce kelp abundance and therefore strongly affect kelp forest community structure. Despite the ecological importance of sea urchins, direct field studies on the role that urchin predators play in shaping urchin populations are rare for southern California. We conducted surveys and manipulative experiments within kelp forests near San Diego, CA, (32–51′28″N, 117–16′00″W) from 2006 to 2009 to determine whether predators such as sheephead (Semicossyphus pulcher) and spiny lobsters (Panulirus interruptus) may be linked to purple urchin (Strongylocentrotus purpuratus) and red urchin (Strongylocentrotus franciscanus) distribution and habitat use, as well as purple urchin density-dependent mortality. Purple urchins were less dense and more cryptic inside a local marine protected area (MPA) that contained high predator abundance than in nearby heavily fished areas, whereas red urchins rarely were found outside the MPA. Urchin proportional mortality was inversely density dependent during the day when sheephead were active, despite fish aggregations in plots of high urchin density, but was density independent during the night when lobsters were active. Urchin mortality was reduced under understory algal cover during the day, but not during the night. Examining whether urchin mortality from predation is density dependent and how habitat complexity influences this relationship is imperative because behavioral changes and increases in urchin populations can have vast ecological and economic consequences in kelp forest communities.