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G.?Zi?baEmail authorView authors OrcID profile M.?Dukowska M.?Przybylski M.?G.?Fox C.?Smith 《Die Naturwissenschaften》2018,105(3-4):26
Providing parental care is potentially costly. Costs can arise through elevated energy expenditure or from an increased risk of mortality. A cost of parental care can also occur because a parent is compromised in their ability to forage. We used pumpkinseed Lepomis gibbosus, a fish with an alternative male mating strategy, to test whether parental males differed in their feeding in comparison with females and cuckolder males. To address this question, we examined the stomach contents of female, cuckolder male, and parental male pumpkinseed during the breeding season over an entire diel cycle. We showed that parental males had a lower total weight of food in their stomachs in comparison with females, while cuckolder males did not. Parental males also had a lower weight and number of chironomids in their stomachs. The temporal pattern of feeding of parental males diverged from that of females, and they had a lower probability of pupal chironomids in their stomachs, which implies spatial segregation in foraging. Parental males had a greater probability of conspecific eggs in their stomachs than females, while the probability of egg cannibalism did not differ between cuckolder males and females. Overall, these finding meet predictions in accordance with an assumption that parental care and territoriality can compromise feeding. 相似文献
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A comprehensive review of climate adaptation in the United States: more than before, but less than needed 总被引:2,自引:0,他引:2
Rosina Bierbaum Joel B. Smith Arthur Lee Maria Blair Lynne Carter F. Stuart Chapin III Paul Fleming Susan Ruffo Missy Stults Shannon McNeeley Emily Wasley Laura Verduzco 《Mitigation and Adaptation Strategies for Global Change》2013,18(3):361-406
We reviewed existing and planned adaptation activities of federal, tribal, state, and local governments and the private sector in the United States (U.S.) to understand what types of adaptation activities are underway across different sectors and scales throughout the country. Primary sources of review included material officially submitted for consideration in the upcoming 2013 U.S. National Climate Assessment and supplemental peer-reviewed and grey literature. Although substantial adaptation planning is occurring in various sectors, levels of government, and the private sector, few measures have been implemented and even fewer have been evaluated. Most adaptation actions to date appear to be incremental changes, not the transformational changes that may be needed in certain cases to adapt to significant changes in climate. While there appear to be no one-size-fits-all adaptations, there are similarities in approaches across scales and sectors, including mainstreaming climate considerations into existing policies and plans, and pursuing no- and low-regrets strategies. Despite the positive momentum in recent years, barriers to implementation still impede action in all sectors and across scales. The most significant barriers include lack of funding, policy and institutional constraints, and difficulty in anticipating climate change given the current state of information on change. However, the practice of adaptation can advance through learning by doing, stakeholder engagements (including “listening sessions”), and sharing of best practices. Efforts to advance adaptation across the U.S. and globally will necessitate the reduction or elimination of barriers, the enhancement of information and best practice sharing mechanisms, and the creation of comprehensive adaptation evaluation metrics. 相似文献
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本研究对尼泊尔全国药用植物的年产量及商业价值进行了评估.我们对尼泊尔15个地区的当地药用植物交易者(n=149)和印度的地区批发商(n=53)进行了无限制问卷调查,借以收集数据.据估计,年交易额的范围为7000~27 000t,案例年份1997~1998年的产量为14 500t.按印度主要市场的地区批发商购买价格计算,相应的年出口额估计为700~3000万美元,1997~1998年为1600万美元.约有10%的农户参与了商品化采集.低海拔生态区在产量和价值两方面均占优势;就价值而言,药草是最重要的生活型.约有36%的产量和51%的价值来自破坏性采集.有人认为,年产量和价值数据仍有可能属于保守估计.本文还简短讨论了本研究结果对喜马拉雅药用植物保护及贸易的意义. 相似文献
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Urban Flood Damage and Greenhouse Scenarios - The Implications for Policy: An Example from Australia
Urban flooding is often used as an illustration of the potentially adverse effects of greenhouse-induced climate change on extreme events. There is however, a paucity of studies that convert climate scenarios into changes in flood damage. This account summarises the use of modelling techniques, for three flood prone urban catchments in south eastern Australia, to assess changes to urban flood losses for the 'most wet' and 'most dry' scenarios for the year 2070. The most wet scenario indicates that annual average flood damage could increase within the range of 2.5 to 10 times, under the most dry scenario flood regimes would be similar to those experienced at present. The socio-economic scenarios based on the changes to flood losses are used to consider policy responses. It is unlikely that many local government authorities will respond because of lack of interest and because of major changes to the climate scenarios proposed over the last decade. Any response is likely to be incremental and accord with the 'no regrets' and the precautionary principle'. 相似文献
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Summary This study reports an aviary experiment aimed at determining what affects social dominance in the great tit (Parus major), especially why older birds (adults) in nature normally dominate younger ones (juveniles). When birds were matched with respect to age, prior residency determined dominance. Without a difference in prior residency older birds dominated younger ones. However, when juvenile birds had a prior residency advantage over adult birds, they often became dominant. This was especially so when the juvenile bird was large relative to the adult bird. When a resident juvenile male was also consorted by a female, he became dominant over an adult male on most occasions. An experiment where the dominant bird was removed and later returned to the aviary failed to produce more than one shift in dominance. However, the proportion of reversals in dominance interactions increased with separation time. It is argued that the fact that dominance depends on prior residency selects for winter residency in the great tit.Offprint requests to: H.G. Smith 相似文献
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The date when a landbird migrant arrives on its breeding grounds may have reproductive consequences. Generally, early arriving individuals begin breeding earlier and consequently experience greater seasonal reproductive performance. Here, we describe relationships between arrival timing and seasonal reproductive performance in the American redstart (Setophaga ruticilla), a long-distance passerine migrant, arriving at northerly breeding grounds in Michigans eastern Upper Peninsula. Evidence suggests that both males and females benefited from early arrival at the breeding grounds. Early males appeared to settle on higher quality territories and hatched nestlings sooner than later arrivals. Early females began their clutches early, produced heavier nestlings and possibly laid more eggs than later arrivals. Larger clutches and heavier offspring increase the likelihood of offspring recruiting into the breeding population. The findings of this study point to fitness consequences arising from when a bird arrives at its breeding grounds. These results also have implications for understanding how events occurring during spring migration influence reproductive performance as migratory delays likely influence arrival timing.Communicated by: W. Wiltschko 相似文献
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