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101.
John F. Paul K. John Scott A. Fred Holland Steven B. Weisberg J. Kevin Summers Andrew Robertson 《Chemistry and Ecology》2013,29(1-4):93-116
The US Environmental Protection Agency's Office of Research and Development has initiated the Environmental Monitoring and Assessment Program (EMAP) to monitor status and trends in the condition of the nation's near coastal waters, forests, wetlands, agro-ecosystems, surface waters, deserts and rangelands. the programme is also intended to evaluate the effectiveness of Agency policies at protecting ecological resources occurring in these systems. Monitoring data collected for all ecosystems will be integrated for regional and national status and trends assessments. the near coastal component of EMAP consists of estuaries, coastal waters, and the Great Lakes. Near coastal ecosystems have been regionalized and classified, and an integrated sampling strategy has been developed. EPA and NOAA have agreed to coordinate and, to the extent possible, integrate the near coastal component of EMAP with the NOAA National Status and Trends Program. A demonstration project was conducted in estuaries of the mid-Atlantic region (Chesapeake Bay to Cape Cod) in the summer of 1990. in 1991, monitoring continued in mid-Atlantic estuaries and was initiated in estuaries of a portion of the Gulf of Mexico. Preliminary results indicate: there are no insurmountable logistical problems with sampling on a regional scale; several of the selected indicators are practical and sensitive on the regional scale; and an efficient effort in future years will provide valuable information on condition of estuarine resources at regional scales. 相似文献
102.
This paper reports a study of costs and benefits of Coral Triangle Initiatives (CTI) and Mangrove Rehabilitation Projects (MRP) in the Solomon Islands. It was observed that the communities have different attitudes and perceptions toward climate change challenges. The different scales and magnitudes of climate change impacts that are perceived at these sites, and the different subsistence realities make them have varied responses and points of view regarding such impacts. For instance, respondents from Oibola experienced the most adverse impacts from climatic change events compared to those living in the Naro and Sairaghi sites. Introduction of CTI and MRP has driven the villagers to travel out far from their traditional fishing grounds to catch enough fish to sell and support their families. This implies higher fishing costs and time for commute. From a social perspective, this weakens the communal bond in the community. In spite of these trade-offs, the respondents expressed satisfaction with the level of benefits received from the projects, which included the rehabilitation of the ecosystems and breeding grounds for fish and habitats around the area. We mapped the costs and benefits of these projects to the villagers, and although no amounts or figures were disclosed, the benefits are compared against corresponding costs. One key factor for the success of the initiatives was the cooperation and involvement of recipient villagers, and even including the management MPAs. 相似文献
103.
104.
Sinks for nitrogen inputs in terrestrial ecosystems: a meta-analysis of 15N tracer field studies 总被引:1,自引:0,他引:1
Templer PH Mack MC Chapin FS Christenson LM Compton JE Crook HD Currie WS Curtis CJ Dail DB D'Antonio CM Emmett BA Epstein HE Goodale CL Gundersen P Hobbie SE Holland K Hooper DU Hungate BA Lamontagne S Nadelhoffer KJ Osenberg CW Perakis SS Schleppi P Schimel J Schmidt IK Sommerkorn M Spoelstra J Tietema A Wessel WW Zak DR 《Ecology》2012,93(8):1816-1829
Effects of anthropogenic nitrogen (N) deposition and the ability of terrestrial ecosystems to store carbon (C) depend in part on the amount of N retained in the system and its partitioning among plant and soil pools. We conducted a meta-analysis of studies at 48 sites across four continents that used enriched 15N isotope tracers in order to synthesize information about total ecosystem N retention (i.e., total ecosystem 15N recovery in plant and soil pools) across natural systems and N partitioning among ecosystem pools. The greatest recoveries of ecosystem 15N tracer occurred in shrublands (mean, 89.5%) and wetlands (84.8%) followed by forests (74.9%) and grasslands (51.8%). In the short term (< 1 week after 15N tracer application), total ecosystem 15N recovery was negatively correlated with fine-root and soil 15N natural abundance, and organic soil C and N concentration but was positively correlated with mean annual temperature and mineral soil C:N. In the longer term (3-18 months after 15N tracer application), total ecosystem 15N retention was negatively correlated with foliar natural-abundance 15N but was positively correlated with mineral soil C and N concentration and C:N, showing that plant and soil natural-abundance 15N and soil C:N are good indicators of total ecosystem N retention. Foliar N concentration was not significantly related to ecosystem 15N tracer recovery, suggesting that plant N status is not a good predictor of total ecosystem N retention. Because the largest ecosystem sinks for 15N tracer were below ground in forests, shrublands, and grasslands, we conclude that growth enhancement and potential for increased C storage in aboveground biomass from atmospheric N deposition is likely to be modest in these ecosystems. Total ecosystem 15N recovery decreased with N fertilization, with an apparent threshold fertilization rate of 46 kg N x ha(-1) x yr(-1) above which most ecosystems showed net losses of applied 15N tracer in response to N fertilizer addition. 相似文献
105.
Within the tropical and subtropical oceans, tuna forage opportunistically on a wide variety of prey. However, little is known
about the trophic ecology of the smallest size classes which play an important role in stock assessments and fisheries management.
The foraging behavior of yellowfin tuna, Thunnus albacares (23.5–154.0 cm FL), collected from nearshore Fish Aggregating Devices (FADs) around Oahu was studied using stable isotope
and stomach contents analyses. Emphasis was placed on small juveniles. Yellowfin tuna changed their diets significantly between
45 and 50 cm forklength (ca. 1.5 kg). Smallest size classes fed on planktonic organisms inhabiting the shallow mixed layer,
primarily larval stomatopod and decapod crustaceans, whereas larger tuna fed on teleosts and adult Oplophorus gracilirostris, a vertically migrating mesopelagic species of shrimp. When interpreting the variation in prey δ
15N values, we considered both their relative trophic position and δ
15N values of the nitrogen at the base of the food web. Based on the distinct diet shift of the yellowfin tuna, demonstrated
by both isotope and stomach content analyses, we propose a critical mass threshold was reached at about 45 cm FL that enabled
sufficient endothermic capability to allow tuna to access prey dwelling in deeper, colder water. These ontogenetic changes
in foraging range and commensurate shift in diet of small tunas would affect their vulnerability to fishing pressure. 相似文献
106.
Consumption rates of marine predators are vital to assessing their trophic impacts and potential consequences of fisheries removal and habitat alteration, yet are rarely estimated. Standard metabolic rates were estimated for juvenile brown stingrays, Dasyatis lata, and used as input parameters for a bioenergetics model to predict consumption rates. Temperature and mass had significant effects on metabolic rates. The energy budget of juvenile brown stingrays was heavily weighted toward metabolism, accounting for 66 % of consumed energy. Growth accounted for 7 % of the energy budget indicating very slow growth potentially due to limited food resources. Population consumption rates suggest potential for strong top-down effects on prey populations due to stingray predation. This study suggests the use of Kāne‘ohe Bay as a nursery habitat for juvenile brown stingrays is a trade-off between increased juvenile survival through predator avoidance and a late age at first maturity due to slow growth rates resulting from low prey availability. 相似文献
107.
F. Kohler T.G. Holland J.S. Kotiaho M. Desrousseaux M.D. Potts 《Conservation biology》2019,33(5):1014-1022
Leading societies toward a more sustainable, equitably shared, and environmentally just future requires elevating and strengthening conversations on the nonmaterial and perhaps unquantifiable values of nonhuman nature to humanity. Debates among conservationists relating to the appropriateness of valuing ecosystems in terms of their human utility have eclipsed the more important and impactful task of expressing conservation concerns in terms that are meaningful to diverse stakeholders. We considered the wide global diversity of perspectives on the biosocial complex—the relationships and interactions between all living species on Earth—and argue that humanity's best chance for effective conservation is to take a pluralistic approach that engages seriously with the worldviews of all stakeholders. Many worldviews—particularly those in indigenous cultures—place a higher value on the spiritual and nonmaterial aspects than what is often represented by the discourse surrounding Western conservation policy. Alternative framings of the biosocial complex that recognize nature's intrinsic value can be powerful motivators for social change and for local-scale conservation efforts. At a national and international level, changing ethical framings of human relationships with nature have started influencing conceptions of human rights relating to the environment and of the rights of nature itself. This change has led to an increased role of the judiciary in promoting environmental sustainability and promoting justice for groups who are most often affected by environmental harms. We hope our essay will motivate the scientific community to change its own perception of what a sound and sustainable relationship between humanity and other species should be and will help citizens become active environmental subjects, connected to the ecosystems around them. 相似文献
108.
David J. Gonthier Jason D. Witter Alison L. Spongberg Stacy M. Philpott 《Chemoecology》2011,21(3):123-130
Nitrogen (N) based secondary metabolite production is thought to be costly to plants because N is required for growth, as
well as, the synthesis of these compounds. Therefore, variation in N availability may result in variation in N-based secondary
metabolite production. Here, we determine the effect of N fertilization on caffeine (N-based alkaloid) production in coffee
(Coffea arabica) seedlings. A growth chamber experiment was performed with three N treatments applied to seedlings. N fertilization increased
plant growth, leaf biomass, and plant N. Caffeine concentration in phloem exudates was greater in high-N fertilized plants
relative to intermediate- and low-N plants. However, leaf, stem, root, and total overall caffeine concentration and content
did not differ across N treatments. These results suggest caffeine in coffee is strongly regulated by genetic factors, and
environment is likely less important to caffeine phenotype. This is among the first studies to investigate the effect of N
fertilization on caffeine within the phloem, which has important implications for herbivores that are sensitive to caffeine
and plant N and feed from the phloem of coffee. 相似文献
109.
Sampling and monitoring for cyanotoxins can be problematic as concentrations change with environmental and hydrological conditions. Current sampling practices (e.g. grab samples) provide data on cyanotoxins present only at one point in time and may miss areas or times of highest risk. Recent research has identified the widespread distribution of anatoxin-producing benthic cyanobacteria in rivers highlighting the need for development of effective sampling techniques. In this study we evaluated the potential of an in situ method known as solid phase adsorption toxin tracking (SPATT) for collecting and concentrating anatoxin-a (ATX) and homoanatoxin-a (HTX) in river water. Fifteen different adsorption substrates were screened for efficiency of ATX uptake, nine of which retained high proportions (>70%) of ATX. Four substrates were then selected for a 24-h trial in a SPATT bag format in the laboratory. The greatest decrease in ATX in the water was observed with powdered activated carbon (PAC) and Strata-X (a polymeric resin) SPATT bags. A 3-d field study in a river containing toxic benthic cyanobacterial mats was undertaken using PAC and Strata-X SPATT bags. ATX and HTX were detected in all SPATT bags. Surface grab samples were taken throughout the field study and ATX and HTX were only detected in one of the water samples, highlighting the limitations of this currently used method. Both Strata-X and PAC were found to be effective absorbent substrates. PAC has the advantage that it is cheap and readily available and appears to continue to sorb toxins over longer periods than Strata-X. SPATT has the potential to be integrated into current cyanobacterial monitoring programmes and would be a very useful and economical tool for early warning of ATX and HTX contamination in water. 相似文献
110.
Breena Holland 《环境政策》2017,26(3):391-412
Climate adaptation politics presents both obstacles and opportunities for correcting inequities that leave some communities especially vulnerable to climate-related environmental harms. By revealing these obstacles and opportunities, theories of procedural justice can help to identify procedural reforms and political strategies that advance the interests of vulnerable populations. An account of procedural justice is proposed that foregrounds the capability for political control over one’s environment, defined as having the political power to influence adaptation decisions. While the variables shaping this capability in the politics of environmental injustice often interact in ways that reproduce environmental inequities, adaptation politics has the potential to produce more transformational outcomes. To illustrate this potential, differences between the politics of environmental injustice and the politics of climate adaptation are drawn on to sketch the basic features of a typology of vulnerable populations’ political capabilities in the politics of climate adaptation, before highlighting the potential points for intervention. 相似文献