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991.
Chandrinou S Stasinakis AS Thomaidis NS Nikolaou A Wegener JW 《Environment international》2007,33(2):226-232
Five bivalve species--Mytilus galloprovinciallis (Mediterranean mussels), Venus gallina (stripped venus), Modiola barbatus L. (bearded horse mussels), Pecten jacobeus (scallops) and Callista chione (hard clams)--were collected from seven areas in Aegean Sea, Greece, between August 2001 and January 2003 and analyzed for organotins (OTs). The concentrations (as geometric means) found were 17.1 ng g-1 for tributyltin (TBT), 18.8 ng g-1 for dibutytltin (DBT), 7.8 ng g-1 for monobutyltin (MBT) and 13.0 ng g-1 for triphenyltin (TPhT) (wet weight), which are at similar or lower levels than those reported worldwide. Studying OTs distribution between different bivalve species, lower concentrations were observed in mediterranean mussels, possibly due to their growth in water column (grown on sea net pens in mussel farms), in contrast to the free-ranging species, collected from fishing grounds. Concentrations of the OTs in the examined bivalves varied seasonally. 相似文献
992.
In beaver ponds, the species diversity, abundance, biomass, and production of cladocerans and the amount of food consumed by them have increased and the composition of dominant species has changed as compared to those in the stretches of small rivers with running water or dammed by man. The stimulating effect of water from a beaver pond has been confirmed in laboratory experiments. The average number of juvenile Ceriodaphnia affinis produced by one female was considerably greater in this water than in the water from flowing and dammed (by man) river stretches. 相似文献
993.
An inventory of rock vegetation has been taken in river valleys on the eastern slope of the southern part of the Northern Urals and the northern part of the Middle Urals. New habitats of some rare plant species, relict communities of forest-steppe species at the northern limit of their distribution, and ultrasmall populations of petrophilous species growing in isolation for a long time have been revealed. In studies on a group of similar specially protected areas (e.g., within river valleys), it is proposed to identify key sites distinguished by the highest species richness of vegetation 相似文献
994.
The dependence of the annual increment of vegetative organs on air temperature and humidity and the amount of precipitation per phenophase, as well as the period of their growth in Scots pine, were studied in the forest-steppe zone of Cisbaikalia. The multiple effect of variation in environmental conditions on the annual increment of organs increased when precipitation in September of the previous year was taken into account. These factors proved to have a stronger effect on variation in the annual increment of needles (R 2 = 0.59, p = 0.00005) than that in the annual ring width (R 2 = 0.38, p = 0.0002). 相似文献
995.
Disasters have the potential to act as focusing events, which can increase the amount of attention on disaster‐related problems and encourage policy action. Understanding of the political characteristics of disaster policymaking is underdeveloped, yet it is known that these features may be dissimilar to those of non‐disaster policy areas, especially concerning the coalitions of policy actors engaged in the disaster policy process. Coalitions in the realm of disaster policy processes may be less likely to form, may look very different, and may have different goals than those in non‐disaster domains. Knowledge of the emergence, composition, and purpose of coalitions in disaster policy is lacking. This paper draws on prior theory and case observations to define and describe the characteristics of a disaster policy subsystem and to build a typology of coalitions that may appear within such a subsystem, providing a foundation upon which scholars can work to study coalition dynamics in disaster policy subsystems. 相似文献
996.
Hermann Comoé Robert Finger Dominique Barjolle 《Mitigation and Adaptation Strategies for Global Change》2014,19(2):123-142
This paper investigates threats to farm management in the northern and central region of Côte d’Ivoire, with a particular focus on climate-related threats. To this end, farmers’ perception and adaptation strategies for climate change have been analyzed. The data were collected from 205 respondents by means of the Focus Groups method, and they were evaluated using a framework analysis. The main reported threats related to the implementation of farming activities are the high cost of inputs and the lack of technical support, which are followed by diseases, insects, and climate variations (scarcity of rains, strong winds, and high temperature). We find that most farmers have a strong perception of changes in climatic conditions. Their perceived impacts on the local environment through evidences like the disappearance of certain farming practices, occurrence of new insects, and the disruption of key time reference periods. Farmers mainly attempt to adapt by adjusting their agricultural calendar, adopting new short-season varieties, and using mixed cropping. We find that the most influential factors for farmers’ adaptation behavior is lack of contact with extension services and the scarcity of rainfall. Our suggestions for future agricultural policies for better adaptation to climate change are to take into account farmers’ perception, to provide suitable climate forecast, and to improve local technical support. 相似文献
997.
Ibrahima Sow Robert K. Dixon Jie Pan Anil Sookdeo Evelyn Swain Laurent Granier 《Mitigation and Adaptation Strategies for Global Change》2014,19(1):93-106
Persistent Organic Pollutants (POPs) threaten human health and the global environment. Recognizing their dangers many countries began to limit or ban POPs production, use, and release in the 1990s. Eventually the Stockholm Convention on POPs, was adopted in 2001 and entered into force in 2004. The Global Environment Facility (GEF) provides financial support to developing country Parties for the implementation of the Stockholm Convention. The GEF’s POPs investment portfolio focuses on: 1) strengthening the capacity of developing country Parties to implement the Stockholm Convention; 2) establishing and supporting partnerships to develop and implement National Implementation Plans (NIPs), and 3) demonstrating and deploying best technologies and practices to reduce POPs emission, including development of safe alternatives. Since 2001 the GEF has committed US$568.8 million to POPs projects and leveraged some US$1474.5 million in co-financing from partners in the public and private sectors, bringing the total value of the GEF POPs portfolio to over US$2 billion. With GEF support, 108 developing country Parties have developed their NIPs. The GEF also financed 109 projects for the implementation of the Convention. Upon completion, these GEF POPs investments will contribute to the disposal of more than 70,000 tons of Polychlorinated Biphenyls (PCBs) oil, contaminated equipments, and waste, more than 40,000 tons of obsolete POPs pesticides and associated waste, and reducing dioxin/furan and mercury emission by introducing environmentally sound technologies and best practices. This paper summarizes: 1) direct and indirect GEF investments to support the goals of the Stockholm Convention; 2) investment case studies on PCB, DichloroDiphenylTrichloroethane (DDT), chlordane and mirex, medical waste, obsolete POPs and engaging civil society; and 3) lessons learned in terms of GEF financing strategies, best technologies and environmental practices to address POPs. 相似文献
998.
Mariela C. Castro Alfredo A. Carlini Rodolfo Sánchez Marcelo R. Sánchez-Villagra 《Die Naturwissenschaften》2014,101(2):77-86
We describe Pliodasypus vergelianus gen. et sp. nov., a Dasypodini armadillo from the middle Pliocene of Venezuela (Vergel Member, San Gregorio Formation). Although scarce, the remains are remarkable because of their geochronologic proximity to the main phase of Great American Biotic Interchange (GABI). The cladistic analysis conducted reveals that Pliodasypus groups with Dasypus and both are sister taxa of Propraopus, whereas Anadasypus is at a basal position. With respect to the records of tribe Dasypodini, after its oldest representative (Anadasypus, middle and late Miocene), the chronologically subsequent form is Pl. vergelianus (middle Pliocene), followed by Dasypus bellus in higher northern latitudes (late Pliocene), and then by widespread occurrences in the Pleistocene of North America (D. bellus) and South America (Propraopus, Dasypus punctatus, and Dasypus novemcinctus). Thus, we infer that Dasypus differentiated in the late Pliocene at low latitudes in the northern South America. It leads to two alternative hypotheses of dispersal: (a) some early Dasypus remained cryptically in South America until the Pleistocene, whereas others dispersed to North America between 2.2 and 2.7 Ma, or (b) they dispersed to North America subsequently to the emersion of the Panamanian isthmus and D. bellus differentiated there; later, during the Pleistocene, D. bellus entered South America and experienced speciation. The same process of re-ingression has been proposed to other xenarthrans, breaking with the traditional assumption that the GABI was unidirectional. 相似文献
999.
D. M. S. Esquivel A. A. C. Corrêa O. S. Vaillant V. Bandeira de Melo G. S. Gouvêa C. G. Ferreira T. A. Ferreira E. Wajnberg 《Die Naturwissenschaften》2014,101(3):245-249
Insects have been used as models for understanding animal orientation. It is well accepted that social insects such as honeybees and ants use different natural cues in their orientation mechanism. A magnetic sensitivity was suggested for the stingless bee Schwarziana quadripunctata, based on the observation of a surprising effect of a geomagnetic storm on the nest-exiting flight angles. Stimulated by this result, in this paper, the effects of a time-compressed simulated geomagnetic storm (TC-SGS) on the nest-exiting flight angles of another stingless bee, Tetragonisca angustula, are presented. Under an applied SGS, either on the horizontal or vertical component of the geomagnetic field, both nest-exiting flight angles, dip and azimuth, are statistically different from those under geomagnetic conditions. The angular dependence of ferromagnetic resonance (FMR) spectra of whole stingless bees shows the presence of organized magnetic nanoparticles in their bodies, which indicates this material as a possible magnetic detector. 相似文献
1000.
Hannah K. Larson Shana K. Goffredi Erica L. Parra Orlando Vargas Adrián A. Pinto-Tomas Terrence P. McGlynn 《Die Naturwissenschaften》2014,101(5):397-406
We document a facultative Bartonella-like Rhizobiales bacterium in the giant tropical ant, Paraponera clavata. In a lowland tropical rainforest in Costa Rica, 59 colonies were assayed for the prevalence of the Bartonella-like bacterium (BLB), 14 of which were positive. We addressed three questions: First, how does the prevalence of BLB within colonies vary with environmental conditions? Second, how does diet affect the prevalence of BLB in P. clavata? Third, how does the distribution of BLB among colonies reflect ambient differences in food resources and foraging habits? A variety of environmental variables that may be predictive of the presence of BLB were measured, and diet manipulations were conducted to test whether the prevalence of BLB responded to supplemental carbohydrate or prey. The ambient frequency of BLB is much higher in young secondary forests, but is nearly absent from older secondary forests. The prevalence of BLB inside field colonies increased over the duration of a 2-week carbohydrate supplementation; however, water and prey supplementation did not alter the prevalence of BLB. The diets of the colonies located in young secondary forest, compared to other habitats, have a diet richer in carbohydrates and lower in prey. The abundance of carbohydrate, or the relative lack of N, in a colony’s diet influences the occurrence of the BLB microbe in P. clavata. As experimental diet manipulations can affect the facultative presence of an N-cycling microbe, a consistent diet shift in diet may facilitate the emergence of tighter symbioses. 相似文献