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131.
Positive polarotaxis in a mayfly that never leaves the water surface: polarotactic water detection in Palingenia longicauda (Ephemeroptera) 总被引:3,自引:2,他引:1
Tisza mayflies, Palingenia longicauda (Olivier 1791), swarm exclusively over the river Tisza (from which the name of the mayfly was derived). This river is bordered
by a high vertical wall of trees and bushes, which hinder P. longicauda to move away horizontally from the water. During swarming, Tisza mayflies fly immediately above the river in such a way that
their cerci touch the water frequently or sweep its surface. This continuous close connection with water and the vertical
wall of the shore and riparian vegetation result in that Tisza mayflies never leave the water surface; consequently, they
need not search for water. Several Ephemeroptera species move away far from water and return to it guided by the horizontal
polarization of water-reflected light. To reveal whether also P. longicauda is or is not polarotactic, we performed a field experiment during the very short swarming period of Tisza mayflies. We show
here that also P. longicauda has positive polarotaxis, which, however, can be observed only under unnatural conditions, when the animals are displaced
from the water and then released above artificial test surfaces. P. longicauda is the first species in which polarotactic water detection is demonstrated albeit it never leaves the water surface, and
thus, a polarotactic water detection seems unnecessary for it. The polarotactic behaviour of Tisza mayflies explains the earlier
observation that these insects swarm above wet asphalt roads running next to river Tisza. 相似文献
132.
R.?Andrew?HayesEmail author Andrew?M.?Piggott Timothy?E.?Smith Helen?F.?Nahrung 《Chemoecology》2014,24(3):95-103
Plant secondary chemistry mediates the ability of herbivores to locate, accept and survive on potential host plants. We examined the relationship between attack by the cerambycid beetle Phoracantha solida and the chemistry of the secondary phloem (inner bark) of two differentially attacked plantation forestry taxa, Corymbia variegata and its hybrid with C. torelliana. We hypothesised that this differential rate of attack may have to do with differences in secondary chemistry between the taxa. We found differences in the bark chemistry of the taxa, both with respect to phenolic compounds and terpenoids. We could detect no difference between bored and non-bored C. variegata trees (the less preferred, but co-evolved host). Hybrid trees were not different in levels of total polyphenols, flavanols or terpenes according to attack status, but acetone extracts were significantly different between bored and non-bored trees. We propose that variations in the bark chemistry explain the differential attack rate between C. variegata and the hybrid hosts. 相似文献
133.
Kodagu district produces 2% of the world’s coffee, in complex, multistoried agroforestry systems. The forests of the district
harbour a large population of the Asian elephant (Elephas maximus). The combined effects of high elephant density and major landscape changes due to the expansion of coffee cultivation are
the cause of human–elephant conflicts (HEC). Mitigation strategies, including electric fences and compensation schemes implemented
by the Forest Department have met with limited success. Building on previous studies in the area, we assessed current spatial
and temporal trends of conflict, analysed local stakeholders’ perceptions and identified factors driving elephants into the
estates. Our study, initiated in May 2007, shows that the intensity of HEC has increased over the last 10 years, exhibiting
new seasonal patterns. Conflict maps and the lack of correlation between physical features of the coffee plantations and elephant
visits suggest elephants move along corridors between the eastern and western forests of the district, opportunistically foraging
when crossing the plantations. Dung analyses indicate elephants have selectively included ripe coffee berries in their diet.
This is, to our knowledge, the first report of wild elephants feeding on coffee berries. If this new behaviour spreads through
the population, it will compound an already severe conflict situation. The behavioural plasticity, the multiplicity of stakeholders
involved, the difficulty in defining the problem and the limits of technical solutions already proposed suggest that HEC in
Kodagu has the ingredients of a “wicked” problem whose resolution will require more shared understanding and problem solving
work amongst the stakeholders. 相似文献
134.
Miguel Azcuna Jortan O. Tun Helen T. Yap Gisela P. Concepcion 《Chemistry and Ecology》2018,34(5):397-411
Marine sponges can produce allelopathic compounds with specific roles in the competition for benthic space. Here we demonstrate that extracts from Callyspongia samarensis (Phylum Porifera) accelerate bleaching in Porites cylindrica (Phylum Cnidaria, Order Scleractinia) and exhibit in vitro anticancer activity. A column chromatography fraction and HPLC fraction, purified from the crude methanol extract of C. samarensis, were incorporated into agar gel cubes at natural concentrations and tested on P. cylindrica corals in a laboratory assay. Statistical analysis of percent bleached area and maximum quantum yield showed that a significant difference existed between P. cylindrica nubbins that were exposed to C. samarensis extracts versus the control group. This suggests that C. samarensis contains allelopathic compounds that can cause bleaching in P. cylindrica, possibly leading to tissue necrosis and death. Furthermore, the aforementioned HPLC fraction exhibited significant growth inhibition of the HCT-116 (human colon cancer) cell line. Understanding the strategies by which sponges exert dominance over other organisms is important because it provides information about the ecological roles of sponge allelopathy and can result in the discovery of compounds with biomedical potential. 相似文献
135.
Brown KW Sarnat JA Suh HH Coull BA Spengler JD Koutrakis P 《Journal of environmental monitoring : JEM》2008,10(9):1041-1051
Despite strong longitudinal associations between particle personal exposures and ambient concentrations, previous studies have found considerable inter-personal variability in these associations. Factors contributing to this inter-personal variability are important to identify in order to improve our ability to assess particulate exposures for individuals. This paper examines whether ambient, home outdoor and home indoor particle concentrations can be used as proxies of corresponding personal exposures. We explore the strength of the associations between personal, home indoor, home outdoor and central outdoor monitoring site ("ambient site") concentrations of sulfate, fine particle mass (PM(2.5)) and elemental carbon (EC) by season and subject for 25 individuals living in the Boston, MA, USA area. Ambient sulfate concentrations accounted for approximately 70 to 80% of the variability in personal and indoor sulfate levels. Correlations between ambient and personal sulfate, however, varied by subject (0.1-1.0), with associations between personal and outdoor sulfate concentrations generally mirroring personal-ambient associations (median subject-specific correlations of 0.8 to 0.9). Ambient sulfate concentrations are good indicators of personal exposures for individuals living in the Boston area, even though their levels may differ from actual personal exposures. The strong associations for sulfate indicate that ambient concentrations and housing characteristics are the driving factors determining personal sulfate exposures. Ambient PM(2.5) and EC concentrations were more weakly associated with corresponding personal and indoor levels, as compared to sulfate. For EC and PM(2.5), local traffic, indoor sources and/or personal activities can significantly weaken associations with ambient concentrations. Infiltration was shown to impact the ability of ambient concentrations to reflect exposures with higher exposures to particles from ambient sources during summer. In contrast in the winter, lower infiltration can result in a greater contribution of indoor sources to PM(2.5) and EC exposures. Placing EC monitors closer to participants' homes may reduce exposure error in epidemiological studies of traffic-related particles, but this reduction in exposure error may be greater in winter than summer. It should be noted that approximately 20% of the EC data were below the field limit of detection, making it difficult to determine if the weaker associations with the central site for EC were merely a result of methodological limitations. 相似文献
136.
Helen C. Wheeler Dominique Berteaux Chris Furgal Kevin Cazelles Nigel G. Yoccoz David Grémillet 《Conservation biology》2019,33(4):861-872
For effective monitoring in social–ecological systems to meet needs for biodiversity, science, and humans, desired outcomes must be clearly defined and routes from direct to derived outcomes understood. The Arctic is undergoing rapid climatic, ecological, social, and economic changes and requires effective wildlife monitoring to meet diverse stakeholder needs. To identify stakeholder priorities concerning desired outcomes of arctic wildlife monitoring, we conducted in-depth interviews with 29 arctic scientists, policy and decision makers, and representatives of indigenous organizations and nongovernmental organizations. Using qualitative content analysis, we identified and defined desired outcomes and documented links between outcomes. Using network analysis, we investigated the structure of perceived links between desired outcomes. We identified 18 desired outcomes from monitoring and classified them as either driven by monitoring information, monitoring process, or a combination of both. Highly cited outcomes were make decisions, conserve, detect change, disseminate, and secure food. These reflect key foci of arctic monitoring. Infrequently cited outcomes (e.g., govern) were emerging themes. Three modules comprised our outcome network. The modularity highlighted the low strength of perceived links between outcomes that were primarily information driven or more derived (e.g., detect change, make decisions, conserve, or secure food) and outcomes that were primarily process driven or more derived (e.g., cooperate, learn, educate). The outcomes expand monitoring community and disseminate created connections between these modules. Key desired outcomes are widely applicable to social–ecological systems within and outside the Arctic, particularly those with wildlife subsistence economies. Attributes and motivations associated with outcomes can guide development of integrated monitoring goals for biodiversity conservation and human needs. Our results demonstrated the disconnect between information- and process-driven goals and how expansion of the monitoring community and improved integration of monitoring stakeholders will help connect information- and process-derived outcomes for effective ecosystem stewardship. 相似文献
137.
Erin K. Cameron Inês S. Martins Patrick Lavelle Jérôme Mathieu Leho Tedersoo Mohammad Bahram Felix Gottschall Carlos A. Guerra Jes Hines Guillaume Patoine Julia Siebert Marten Winter Simone Cesarz Olga Ferlian Holger Kreft Thomas E. Lovejoy Luca Montanarella Alberto Orgiazzi Henrique M. Pereira Helen R. P. Phillips Josef Settele Diana H. Wall Nico Eisenhauer 《Conservation biology》2019,33(5):1187-1192
Human activities are accelerating global biodiversity change and have resulted in severely threatened ecosystem services. A large proportion of terrestrial biodiversity is harbored by soil, but soil biodiversity has been omitted from many global biodiversity assessments and conservation actions, and understanding of global patterns of soil biodiversity remains limited. In particular, the extent to which hotspots and coldspots of aboveground and soil biodiversity overlap is not clear. We examined global patterns of these overlaps by mapping indices of aboveground (mammals, birds, amphibians, vascular plants) and soil (bacteria, fungi, macrofauna) biodiversity that we created using previously published data on species richness. Areas of mismatch between aboveground and soil biodiversity covered 27% of Earth's terrestrial surface. The temperate broadleaf and mixed forests biome had the highest proportion of grid cells with high aboveground biodiversity but low soil biodiversity, whereas the boreal and tundra biomes had intermediate soil biodiversity but low aboveground biodiversity. While more data on soil biodiversity are needed, both to cover geographic gaps and to include additional taxa, our results suggest that protecting aboveground biodiversity may not sufficiently reduce threats to soil biodiversity. Given the functional importance of soil biodiversity and the role of soils in human well-being, soil biodiversity should be considered further in policy agendas and conservation actions by adapting management practices to sustain soil biodiversity and considering soil biodiversity when designing protected areas. 相似文献
138.
Kate E. Watermeyer Gurutzeta Guillera-Arroita Payal Bal Michael J. Burgass Lucie M. Bland Ben Collen Chris Hallam Luke T. Kelly Michael A. McCarthy Tracey J. Regan Simone Stevenson Brendan A. Wintle Emily Nicholson 《Conservation biology》2021,35(2):492-501
Global biodiversity indices are used to measure environmental change and progress toward conservation goals, yet few indices have been evaluated comprehensively for their capacity to detect trends of interest, such as declines in threatened species or ecosystem function. Using a structured approach based on decision science, we qualitatively evaluated 9 indices commonly used to track biodiversity at global and regional scales against 5 criteria relating to objectives, design, behavior, incorporation of uncertainty, and constraints (e.g., costs and data availability). Evaluation was based on reference literature for indices available at the time of assessment. We identified 4 key gaps in indices assessed: pathways to achieving goals (means objectives) were not always clear or relevant to desired outcomes (fundamental objectives); index testing and understanding of expected behavior was often lacking; uncertainty was seldom acknowledged or accounted for; and costs of implementation were seldom considered. These gaps may render indices inadequate in certain decision-making contexts and are problematic for indices linked with biodiversity targets and sustainability goals. Ensuring that index objectives are clear and their design is underpinned by a model of relevant processes are crucial in addressing the gaps identified by our assessment. Uptake and productive use of indices will be improved if index performance is tested rigorously and assumptions and uncertainties are clearly communicated to end users. This will increase index accuracy and value in tracking biodiversity change and supporting national and global policy decisions, such as the post-2020 global biodiversity framework of the Convention on Biological Diversity. 相似文献
139.
Future agriculture with minimized phosphorus losses to waters: Research needs and direction 总被引:3,自引:0,他引:3
Andrew N. Sharpley Lars Bergström Helena Aronsson Marianne Bechmann Carl H. Bolster Katarina Börling Faruk Djodjic Helen P. Jarvie Oscar F. Schoumans Christian Stamm Karin S. Tonderski Barbro Ulén Risto Uusitalo Paul J. A. Withers 《Ambio》2015,44(2):163-179
The series of papers in this issue of AMBIO represent technical presentations made at the 7th International Phosphorus Workshop (IPW7), held in September, 2013 in Uppsala, Sweden. At that meeting, the 150 delegates were involved in round table discussions on major, predetermined themes facing the management of agricultural phosphorus (P) for optimum production goals with minimal water quality impairment. The six themes were (1) P management in a changing world; (2) transport pathways of P from soil to water; (3) monitoring, modeling, and communication; (4) importance of manure and agricultural production systems for P management; (5) identification of appropriate mitigation measures for reduction of P loss; and (6) implementation of mitigation strategies to reduce P loss. This paper details the major challenges and research needs that were identified for each theme and identifies a future roadmap for catchment management that cost-effectively minimizes P loss from agricultural activities. 相似文献
140.
We used data from various space-borne sensors to monitor the marine ecosystem in the northwestern Mediterranean Sea, at the
Costa Dorada, between the City of Barcelona and the estuary of the river Ebro. The aim of this study was to demonstrate that
the combination of different remote sensing data (acquired at different electromagnetic frequencies) allows for an improved
monitoring system, in particular for a better monitoring of the marine ecosystem and, hence, a better coastal zone management.
We present remote sensing data acquired by the Synthetic Aperture Radar (SAR) and the Along-Track Scanning Radiometer (ATSR)
aboard the Second European Remote Sensing Satellite (ERS-2), and by the Sea-viewing Wide Field-of-view Sensor (Sea WiFS) on
the SeaStar satellite. By combining the different data we are able to overcome specific drawbacks of the single sensors, like
an insufficient temporal coverage, or a strong dependence on weather and daylight conditions.
Within the study area two main features have been selected as examples, which are well visible on many of the analysed images.
The first one exhibits a higher load of chlorophyll-a and surface-active compounds and a lower sea surface temperature (SST),
which is likely to be caused by the plume of the river Llobregat, southwest of Barcelona. It can clearly be seen from the
imagery how the river plume is driven along the coast by the local currents. The second feature can be related to cooling
water being released from a nuclear power plant and causing turbulence in the water body, which in turn gives rise to signatures
visible on the ERS-SAR imagery. 相似文献