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51.
Effects of flow regimes altered by dams on survival, population declines, and range-wide losses of California river-breeding frogs 总被引:1,自引:0,他引:1
Kupferberg SJ Palen WJ Lind AJ Bobzien S Catenazzi A Drennan J Power ME 《Conservation biology》2012,26(3):513-524
Widespread alteration of natural hydrologic patterns by large dams combined with peak demands for power and water delivery during summer months have resulted in frequent aseasonal flow pulses in rivers of western North America. Native species in these ecosystems have evolved with predictable annual flood-drought cycles; thus, their likelihood of persistence may decrease in response to disruption of the seasonal synchrony between stable low-flow conditions and reproduction. We evaluated whether altered flow regimes affected 2 native frogs in California and Oregon (U.S.A.) at 4 spatial and temporal extents. We examined changes in species distribution over approximately 50 years, current population density in 11 regulated and 16 unregulated rivers, temporal trends in abundance among populations occupying rivers with different hydrologic histories, and within-year patterns of survival relative to seasonal hydrology. The foothill yellow-legged frog (Rana boylii), which breeds only in flowing water, is more likely to be absent downstream of large dams than in free-flowing rivers, and breeding populations are on average 5 times smaller in regulated rivers than in unregulated rivers. Time series data (range = 8 - 19 years) from 5 populations of yellow-legged frogs and 2 populations of California red-legged frogs (R. draytonii) across a gradient of natural to highly artificial timing and magnitude of flooding indicate that variability of flows in spring and summer is strongly correlated with high mortality of early life stages and subsequent decreases in densities of adult females. Flow management that better mimics natural flow timing is likely to promote persistence of these species and others with similar phenology. 相似文献
52.
Wendy Burton 《Local Environment》2013,18(8):712-726
ABSTRACTCivil society’s potential as a force for solving complex societal problems – particularly those that require a challenge to the status quo – has provoked practical and theoretical interest, with its potential largely reliant on the perception that it is a ready if variable source of social capital resources. However, there are no guarantees that civil society will use its social capital for the greater good. Civil society encompasses a range of groups, some more inward-looking and oriented to private interests, and others more outward-looking and oriented to public interests. This divergent character of civil society was evident in the three campaigns for greenspace protection that eventually led to the creation of the Toronto region greenbelt, where civil society organisations (CSOs) from both growth and conservation camps contended for influence, each succeeding at different times. But over time (a time when state actors were increasingly in need of non-state partners to help solve complex governance problems), coalitions of environmental CSOs in the three campaigns – to protect the Niagara Escarpment, Oak Ridges Moraine and surrounding countryside – became more effective at influencing government to protect greenspace. A comparison of the coalitions using a framework based on key attributes of CSOs – missions and memberships – suggests that the environmental coalitions were more effective when they recruited more members with a diverse set of resources arising from both bonding and bridging social capital. In general, the more inclusive and public-interested the CSOs, the more effective the challenge to the status quo. 相似文献
53.
A review of recent literature in the fields of operations, supply chain, and management indicates there is on-going interest in improving new product development (NPD) performance. Three-dimensional concurrent engineering (3DCE), the simultaneous design of product, process and supply chain have been proposed as a way to improve traditional NPD outcomes, such as reduced time to market, lower costs, and improved customer acceptance. There appears to be a lesser concern associated with the environmental impacts of new products. Environmentally responsible manufacturing (ERM) on new product development focuses on reduced emissions, hazardous materials elimination, and lower product weight without sacrificing functionality. This paper explores the following issue: will employing 3DCE to integrate NPD and ERM yield better benefits than the separate and uncoordinated application of environmental goals and NPD initiatives? 相似文献
54.
As part of the right of indigenous cultures to self-determination, several international bodies have recognized and addressed the role of indigenous communities in natural resources management, including the conservation of biodiversity. In the United States, disagreements regarding the application of the federal Endangered Species Act to Native American tribes have hindered the relationship between the federal and tribal governments on endangered species recovery. Our research examines the efforts of one Native American tribe, the Nez Perce, and the United States federal government to collaborate on federal gray wolf recovery in central Idaho. We interviewed members of the Nez Perce Tribe and U.S. Fish and Wildlife Service to characterize their relationship and explore the context in which the recovery program was implemented. Respondents attributed the success of the biological aspects of wolf recovery to the robustness of the wolf as a species and to close interagency coordination at the operational level. However, differences of opinion existed between the Tribe and Service concerning program funding, policy planning, and the rights and role of the Tribe in wolf management via co-management and cooperative management regimes. Respondents from both governments noted a clear hierarchical relationship at the strategic level, where policy planning and decision-making rested with the federal government. Lessons drawn from this case study can be applied across the international spectrum to improving partnerships, particularly at the strategic level, between indigenous and non-indigenous governance structures for protecting endangered species. 相似文献
55.
Xiujuan Chen Yunqiu Liu Gordon Huang Chunjiang An Renfei Feng Yao Yao Wendy Huang Shuqing Weng 《Frontiers of Environmental Science & Engineering》2022,16(12):153
56.
Summary. Tannins are plant defense compounds that exhibit antibiotic (e.g. toxic) and antixenotic (e.g. repellent) effects against
an array of plant pests. They are broadly divided into two major groups, hydrolysable tannins (gallotannins and ellagitannins)
and proanthocyanidins, each with an undetermined number of compounds. We investigated constitutive levels of hydrolysable
tannins and proanthocyanidins in the leaves and stems of American (Castanea dentata Marshall) (Fagales: Fagaceae) and Chinese (C. mollissima Blume) chestnut. American chestnut contained more proanthocyanidins in leaves and stems than Chinese chestnut, but Chinese
chestnut contained more foliar hydrolysable tannins. Regardless of these differences, gypsy moth (Lymantria dispar L, Lepidoptera: Lymantriidae) performance did not differ when fed American and Chinese chestnuts. We also investigated the
effects of jasmonic acid (JA) treatment on differential tannin induction in American and Chinese chestnut leaves and stems.
JA treatment increased proanthocyanidins in American chestnut stems and hydrolysable tannins in both tissue types of American
chestnut, but did not influence tannin concentrations in Chinese chestnut leaves or stems. HPLC-ESI-MS analysis of pooled
samples suggested that hydrolysable tannins in each tissue were qualitatively comprised primarily of ellagitannins, and JA
generally increased the number of hydrolysable tannins that could be detected by ESI-MS. Third, we investigated the performance
of gypsy moths on JA treated and untreated American and Chinese chestnut. Caterpillar relative growth was not influenced by
JA treatment on Chinese chestnut, but decreased in response to JA application on American chestnut. Our results indicate that
JA-dependent defenses differ between these chestnut species. This study improves our understanding of ecologically important
differences in tannin induction and herbivore susceptibility in Castanea, and has important implications in efforts for American chestnut restoration and commercial chestnut production. 相似文献
57.
Harrad S Robson M Hazrati S Baxter-Plant VS Deplanche K Redwood MD Macaskie LE 《Journal of environmental monitoring : JEM》2007,9(4):314-318
The environmentally prevalent polybrominated diphenyl ether (PBDE) #47 and polychlorinated biphenyls (PCBs) #28 and #118 were challenged for 24 hours with a novel biomass-supported Pd catalyst (Bio-Pd(0)). Analysis of the products via GC-MS revealed the Bio-Pd(0) to cause the challenged compounds to undergo stepwise dehalogenation with preferential loss of the least sterically hindered halogen atom. A mass balance for PCB #28 showed that it is degraded to three dichlorobiphenyls (33.9%), two monochlorobiphenyls (12%), and biphenyl (30.7%). The remaining mass was starting material. In contrast, while PCB #118 underwent degradation to yield five tetra- and five trichlorinated biphenyls, no less chlorinated products or biphenyl were detected, and the total mass of degraded products was 0.3%. Although the Bio-Pd(0) material was developed for treatment of PCBs, a mass balance for PBDE #47 showed that the biocatalyst could prove a potentially useful method for treatment of PBDEs. Specifically, 10% of PBDE #47 was converted to identifiable lower brominated congeners, predominantly the tribrominated PBDE #17 and the dibrominated PBDE #4, 75% remained intact, while 15% of the starting mass was unaccounted for. 相似文献
58.
Wendy M. Jackson 《Behavioral ecology and sociobiology》1991,28(4):271-276
Summary Winners of aggressive interactions often continue to win in future encounters. I propose that this phenomenon is a by-product of two other phenomena occurring simultaneously: first, initiators of aggressive interactions typically win those interactions and, second, winners of aggressive encounters often become more likely to initiate future interactions. I propose that these phenomena can be explained, in turn, by selection favoring an individual's initiating an interaction only when it is likely to win that interaction. I found support for this two-step explanation for the winning begets winning phenomenon by observing aggressive interactions among captive dark-eyed juncos (Junco hyemalis oreganus). First, initiators of interactions almost always won. Second, based on characteristics of winners in birds' home aviaries, I could predict which birds would initiate against novel competitors — winners were long-winged males with dark hoods, and birds with these characteristics were more likely to be the first to initiate in novel triads. In addition, aggression was directed preferentially towards other dark-hooded males. The results of this study may expand our understanding of the dynamics of aggressive interactions. 相似文献
59.
Gary D. Lynne 《Journal of the American Water Resources Association》1988,24(1):95-101
ABSTRACT: Economic information for efficient water allocation is difficult and costly to acquire under administrative water systems evolving under the Model Water Code. One approach to obtaining more information is to use a simulator like the Florida AGWATER model. The advantage of AGWATER is the potential for realistic prediction, because it operates at the field and day levels, using detailed information for each crop and tract. Unfortunately, such simulators are complex and require large amounts of costly input data. A better solution to the information problem may be to use markets for the marketable goods associated with water, because information is inherent in such a process. This approach will allow limited modeling and management resources to be put into using water models to generate information for the goods dependent on water that are difficult to market, like wildlife services. 相似文献
60.