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121.
Simon Anthony Morley Koh Siang Tan Robert W. Day Stephanie M. Martin Hans-O. Pörtner Lloyd S. Peck 《Marine Biology》2009,156(10):1977-1984
The upper thermal limits for burrowing and survival were compared with micro-habitat temperature for anomalodesmatan clams:
Laternula elliptica (Antarctica, 67°S); Laternula recta, (temperate Australia, 38°S) and Laternula truncata (tropical Singapore, 1°N). Lethal limits (LT50) were higher than burrowing limits (BT50) in L. elliptica (7.5–9.0 and 2.2°C) and L. recta (winter, 32.8–36.8 and 31.1–32.8°C) but the same range for L. truncata (33.0–35.0 and 33.4–34.9°C). L. elliptica and L. truncata had a BT50 0.4 and 2.4–3.9°C, respectively, above their maximum experienced temperature. L. recta, which experience solar heating during midday low tides, had a BT50 0.7–2.4°C below and a range for LT50 that spanned their predicted environmental maximum (33.5°C). L. recta showed no seasonal difference in LT50 or BT50. Our single genus comparisons contrast with macrophysiological studies showing that temperate species cope better with elevated
temperatures.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
122.
Kyle Hamish Elliott Roger D. Bull Anthony J. Gaston Gail K. Davoren 《Behavioral ecology and sociobiology》2009,63(12):1773-1785
How predators vary search patterns in response to prey predictability is poorly known. For example, marine invertebrates may
be predictable but of low energy value, while fish may be of higher energy value but unpredictable at large (pelagic schools)
or small (solitary benthics) spatial scales. We investigated the search patterns of the thick-billed murre (Uria lomvia), an Arctic seabird feeding on invertebrates, pelagic fish, or benthic fish. Foraging ranges at the Coats Island colony are
generally smaller (<240 min per trip) than at larger colonies, and many birds specialize in foraging tactics and diet. Underwater
search times for benthic fish were higher than for pelagic fish or invertebrates while above-water search times for pelagic
fish were higher than for benthic fish or invertebrates. There were few stops during trips. Total trip time, flying time,
number of flights, and number of dives were intercorrelated and increased with prey energy content, suggesting that longer
trips involved fewer prey encounters due to selection of higher-quality, but rarer, prey items. Flight times were not Lévy-distributed
and seabirds may have used area-restricted searches. The high degree of specialization, apparent absence of information center
effects, and reduced above-water searching times may be linked to the relatively small colony size and the resulting short
commuting distances to feeding areas, leading to greater prey predictability. We concluded that prey predictability over various
scales affected predator search patterns. 相似文献
123.
The influence of successional processes and disturbance on the structure of Tsuga canadensis forests
Old-growth forests are valuable sources of ecological, conservation, and management information, yet these ecosystems have received little study in New England, due in large part to their regional scarcity. To increase our understanding of the structures and processes common in these rare forests, we studied the abundance of downed coarse woody debris (CWD) and snags and live-tree size-class distributions in 16 old-growth hemlock forests in western Massachusetts. Old-growth stands were compared with eight adjacent second-growth hemlock forests to gain a better understanding of the structural differences between these two classes of forests resulting from contrasting histories. In addition, we used stand-level dendroecological reconstructions to investigate the linkages between disturbance history and old-growth forest structure using an information-theoretic model selection framework. Old-growth stands exhibit a much higher degree of structural complexity than second-growth forests. In particular, old-growth stands had larger overstory trees and greater volumes of downed coarse woody debris (135.2 vs. 33.2 m3/ha) and snags (21.2 vs. 10.7 m3/ha). Second-growth stands were characterized by either skewed unimodal or reverse-J shaped diameter distributions, while old-growth forests contained bell-shaped, skewed unimodal, rotated sigmoid, and reverse J-shaped distributions. The variation in structural attributes among old-growth stands, particularly the abundance of downed CWD, was closely related to disturbance history. In particular, old-growth stands experiencing moderate levels of canopy disturbance during the last century (1930s and 1980s) had greater accumulations of CWD, highlighting the importance of gap-scale disturbances in shaping the long-term development and structural characteristics of old-growth forests. These findings are important for the development of natural disturbance-based silvicultural systems that may be used to restore important forest characteristics lacking in New England second-growth stands by integrating structural legacies of disturbance (e.g., downed CWD) and resultant tree-size distribution patterns. This silvicultural approach would emulate the often episodic nature of CWD recruitment within old-growth forests. 相似文献
124.
Although most long-term studies of consumer-resource (e.g., predator-prey) interactions select species showing cyclic population dynamics, strong consumer-resource interactions can also produce irregular, noncyclic dynamics. Here, we present a case in which a seed predator, the tephritid fruit fly Euphranta connexa, shows fluctuations in density of more than two orders of magnitude over a 22-year period. To explain these fluctuations, we analyzed a stage-specific data set to quantify the density-dependent and density-independent components of larval survivorship and realized fecundity. Both larval survivorship and realized fecundity were strongly density dependent. Larval survivorship dropped from 0.62 at low larval density to 0.081 at high larval density, whereas fecundity dropped from 84.3 to 0.32 eggs per individual, more than a 100-fold decrease. We divided density-independent variation in E. connexa population dynamics into components for variability in (1) larval survivorship, (2) realized fecundity, and (3) annual fruit abundance. Of these components, 96% of the density-independent variance in per capita population growth rates was caused by fluctuations in fruit abundance. This highlights the importance of the strong consumer-resource interactions in driving fluctuations in E. connexa abundance. It also demonstrates that E. connexa dynamics are remarkably simple, and aside from the 4% of unexplained variance in per capita population growth rates, our understanding of E. connexa dynamics is remarkably complete. 相似文献
125.
Gro Harlaug Olsen Michael L. Carroll Paul E. Renaud William G. AmbroseJr Ragni Olssøn JoLynn Carroll 《Marine Biology》2007,151(6):2167-2176
We assessed the effects of crude oil and drill cuttings on sediment oxygen demand (SOD) of marine benthic communities from
Arctic (Barents Sea) and temperate (Oslofjord) areas of the Norwegian continental shelf. Field-collected cores in both areas
were subjected to three different treatments: two concentrations of hydrocarbon-contaminated sediments, and drill cuttings
(DC). Cores were incubated for 21 days at 5°C (Barents Sea) and at 10°C (Oslofjord) during which SOD was measured five times.
We observed significantly higher SOD in the high oil concentration (HOC) and DC treatments compared to control cores from
the Arctic, but not in the temperate Oslofjord. No difference was observed between the low oil concentration (LOC) and control
at either location. The clear differences in the response of Arctic benthic communities to petroleum compounds compared to
temperate benthic communities is likely related to differences in community structure, sensitivity of individual taxa to petroleum-related
compounds and different contamination history of the two study areas. 相似文献
126.
Hosein Ghaedi Payam Kalhor Ming Zhao Peter T. Clough Edward J. Anthony Paul S. Fennell 《Frontiers of Environmental Science & Engineering》2022,16(7):92
127.
K. Bruce Jones Daniel T. Heggem Timothy G. Wade Anne C. Neale Donald W. Ebert Maliha S. Nash Megan H. Mehaffey Karl A. Hermann Anthony R. Selle Scott Augustine Iris A. Goodman Joel Pedersen David Bolgrien J. Max Viger Dean Chiang Cindy J. Lin Yehong Zhong Joan Baker Rick D. Van Remortel 《Environmental monitoring and assessment》2000,64(1):227-245
The Environmental Monitoring and Assessment Program (EMAP) is proposing an ambitious agenda to assess the status of streams and estuaries in a 12-State area of the western United States by the end of 2003. Additionally, EMAP is proposing to access landscape conditions as they relate to stream and estuary conditions across the west. The goal of this landscape project is to develop a landscape model that can be used to identify the relative risks of streams and estuaries to potential declines due to watershed-scale, landscape conditions across the west. To do so, requires an understanding of quantitative relationships between landscape composition and pattern metrics and parameters of stream and estuary conditions. This paper describes a strategic approach for evaluating the degree to which landscape composition and pattern influence stream and estuary condition, and the development and implementation of a spatially-distributed, landscape analysis approach. 相似文献
128.
Rebecca Swenson Natalie Olsen 《Environmental Communication: A Journal of Nature and Culture》2018,12(7):973-988
Branded platforms are a growing “gray-zone” of marketing and media messages, in which corporations and news journalists partner to create content that supports strategic corporate goals while aligning with a publication’s scope of editorial coverage. As corporations are key influencers of and contributors to environmental communication, this trend has the potential to change environmental dialogue. In this article, we closely examine messages about food and sustainability, created in partnership by Chipotle Mexican Grill and the Huffington Post news site. We illustrate how use of a branded platform expanded the scope of environmental topics, issues, and frames that Chipotle addresses, how frames identified here connect to frames in coverage of science-related issues, as identified by other scholars, and discuss how branded platforms allow corporations to draw attention to polarizing environmental issues while protecting stakeholder relationships and brand reputation. 相似文献
129.
"二噁英"是指具有相似化学结构和生物特征的一族化合物,分别属于三大类别:多氯代二苯并二噁英(PC-DDs),多氯代二苯并呋喃(PCDFs)以及多氯联苯(PCBs).PCDDs和PCDFs无商业目的性生产,而是在大量的人类活动中产生的.自然过程也可以产生PCDDs和PCDFs.在过去的十年里,环境立法机构和企业一起致力于减少二噁英的排放. 相似文献
130.
Christian Riisager-Simonsen Olivia Rendon Anders Galatius Morten Tange Olsen Nicola Beaumont 《Conservation biology》2020,34(5):1152-1164
The goal of ecosystem-based management (EBM) is to support a sustainable and holistic multisectored management approach, and is recognized in a number of international policy frameworks. However, it remains unknown how these goals should be linked to assessments and management plans for marine fauna, such as mammals and fish stocks. It appears particularly challenging to carry out trade-off analyses of various ocean uses without a framework that integrates knowledge of environmental, social, and economic benefits derived from nonstationary marine fauna. We argue this gap can be filled by applying a version of the ecosystem-service approach at the population level of marine fauna. To advance this idea, we used marine mammals as a case study to demonstrate what indicators could operationalize relevant assessments and deliver an evidence base for the presence of ecosystem services and disservices derived from marine mammals. We found indicators covering common ecosystem service categories feasible to apply; examples of indicator data are already available in the literature for several populations. We encourage further exploration of this approach for application to marina fauna and biodiversity management, with the caveat that conceptual tensions related to the use of the ecosystem service concept itself needs to be addressed to ensure acceptance by relevant stakeholders. 相似文献