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61.
Nutrient enrichment of habitats (eutrophication) is considered to be one of the main causes of plant diversity decline worldwide. Several experiments have shown a rapid loss of species in the first years after fertilization started. However, little is known about changes in species richness in the long term. Here, we use a 50-year-old field experiment with a range of fertilization treatments in grasslands that were mown twice each year in the center of The Netherlands. We show that species richness in all plots initially declined but started to recover after approximately 25 years of continued fertilization. This was also true for the heavily fertilized treatment (NPK). In NPK-fertilized plots, the decline was strongest and associated with a strong divergence of plant trait composition from the control, reflecting a shift to a plant community adapted to nutrient-rich conditions. During the subsequent period of increase in species richness, the trait composition remained stable. These results show that plant species richness can, at least partially, recover after an initial diversity decline caused by fertilization. 相似文献
62.
Eugenia Naro-Maciel Brendan Reid Katherine E. Holmes Daniel R. Brumbaugh Meredith Martin Rob DeSalle 《Marine Biology》2011,158(9):2027-2041
To investigate population differentiation in a comparative and historical context, segments of the mitochondrial cytochrome
c oxidase subunit I gene and the control region were sequenced in Panulirus argus from nine sites along approximately 1,500 km of the Northern Caribbean Sea (n = 326) and analyzed with respect to available panulirid data. A mismatch analysis and Fu’s F
S test uncovered a signature of historical population expansion around the time of the Last Glacial Maximum. Significant population
structure was not detected in the area. The data supported a hypothesis of panmixia resulting from ongoing larval transport
by ocean currents and historical population expansion. Despite high intraspecific divergence levels at COI within Panulirus argus and several other Panulirus species, genetic species identification through DNA barcoding was feasible using either a modified distance threshold or
a character-based approach. 相似文献
63.
Frederick Amon-Armah Emmanuel K. Yiridoe Nafees H. M. Ahmad Dale Hebb Rob Jamieson David Burton Ali Madani 《Environmental management》2013,52(5):1177-1191
Government priorities on provincial Nutrient Management Planning (NMP) programs include improving the program effectiveness for environmental quality protection, and promoting more widespread adoption. Understanding the effect of NMP on both crop yield and key water-quality parameters in agricultural watersheds requires a comprehensive evaluation that takes into consideration important NMP attributes and location-specific farming conditions. This study applied the Soil and Water Assessment Tool (SWAT) to investigate the effects of crop and rotation sequence, tillage type, and nutrient N application rate on crop yield and the associated groundwater ${\text{NO}_{3}}^{ - } {\text{-N }}$ leaching and sediment loss. The SWAT model was applied to the Thomas Brook Watershed, located in the most intensively managed agricultural region of Nova Scotia, Canada. Cropping systems evaluated included seven fertilizer application rates and two tillage systems (i.e., conventional tillage and no-till). The analysis reflected cropping systems commonly managed by farmers in the Annapolis Valley region, including grain corn-based and potato-based cropping systems, and a vegetable-horticulture system. ANOVA models were developed and used to assess the effects of crop management choices on crop yield and two water-quality parameters (i.e., ${\text{NO}_{3}}^{ - } {\text{-N }}$ leaching and sediment loading). Results suggest that existing recommended N-fertilizer rate can be reduced by 10–25 %, for grain crop production, to significantly lower ${\text{NO}_{3}}^{ - } {\text{-N }}$ leaching (P > 0.05) while optimizing the crop yield. The analysis identified the nutrient N rates in combination with specific crops and rotation systems that can be used to manage ${\text{NO}_{3}}^{ - } {\text{-N }}$ leaching while balancing impacts on crop yields within the watershed. 相似文献
64.
Laura N. H. Verbrugge Riyan J. G. Van den Born H. J. Rob Lenders 《Environmental management》2013,52(6):1562-1573
Not much is known about lay public perceptions of non-native species and their underlying values. Public awareness and engagement, however, are important aspects in invasive species management. In this study, we examined the relations between the lay public’s visions of nature, their knowledge about non-native species, and their perceptions of non-native species and invasive species management with a survey administered in the Netherlands. Within this framework, we identified three measures for perception of non-native species: perceived risk, control and engagement. In general, respondents scored moderate values for perceived risk and personal engagement. However, in case of potential ecological or human health risks, control measures were supported. Respondents’ images of the human–nature relationship proved to be relevant in engagement in problems caused by invasive species and in recognizing the need for control, while images of nature appeared to be most important in perceiving risks to the environment. We also found that eradication of non-native species was predominantly opposed for species with a high cuddliness factor such as mammals and bird species. We conclude that lay public perceptions of non-native species have to be put in a wider context of visions of nature, and we discuss the implications for public support for invasive species management. 相似文献
65.
Too often, mining developments provide short-term jobs and taxes, and long-term environmental and community degradation. The 'precautionary principle', as practised by the European Union and increasingly by other nations, may provide an opportunity for local communities and others who bear the brunt of mining to employ a cautionary approach to mine permitting. Using the case of the Zortman-Landusky gold mine in Montana, the article illustrates how the precautionary principle might have precluded the tremendous losses suffered by the Fort Belknap residents who live near the now abandoned mine. The Native Americans and other protestors against the mine were correct in their worries about mine drainage affecting their watercourses and the precautionary principle might have limited mine development. The case also illustrates that economic data on mining companies need to go well beyond simple reclamation bond capability in order to avoid bankruptcy resulting in the neighbours and the government having to pay for clean-up. 相似文献
66.
Ryan Plummer Jonas Velaniškis Danuta de Grosbois Reid D. Kreutzwiser Rob de Loë 《Environmental Science & Policy》2010,13(6):535-548
While new environmental policies and procedures often are developed incrementally, they can also result from crises or other significant events. In situations where policies and procedures are introduced in response to a crisis, questions about the strengths and weaknesses of existing mechanisms, and the extent to which they can be used to address concerns, may be ignored. This paper explores the complexities of introducing new policies and processes where planning systems and procedures already exist. Drinking water source protection policies that are being developed in response to the tragic events in Walkerton, Ontario, Canada serve as the context for the inquiry. Three case study watersheds were selected to reflect the diversity of municipal jurisdictions and water supply systems in Ontario. A content analysis was undertaken on regulatory and non-regulatory policy documents to determine the extent to which they addressed elements of the multi-barrier approach for drinking water safety. Findings from the research reveal considerable evidence of the multi-barrier approach in the policy and guiding documents analyzed. Policy development in response to a crisis can advance progress on the issue of drinking water safety and coincide with emerging governance strategies. Policy effectiveness may be enhanced by considering existing policies as well as contextual and jurisdictional differences. 相似文献
67.
Andrew Kelly Julio Lumbreras Rob Maas Tiziano Pignatelli Francisco Ferreira Anna Engleryd 《Environmental Science & Policy》2010,13(1):28-41
The Gothenburg Protocol set national emission ceilings for transboundary air pollutants in 2010. These ceilings were formulated in 1999 using the Regional Air Pollution Information and Simulation (RAINS) model and national forecast data. The 2010 ceiling deadline is approaching as is a revision process which may lead to the setting of emission ceilings for 2020. This paper considers the original 1999 projections of six countries that were used within the RAINS model to inform the setting of their respective Gothenburg Protocol 2010 emission ceilings. These data are then contrast against recent inventory data and contemporary short-term forecasts out to 2010. These recent forecasts indicate that major downward shifts in the trends of pollutant emissions have been achieved, and whilst compliance challenges remain, there is a clear indication of the potential of such international agreements and their associated legislative and policy driven mechanisms. However, in a process governed by a maxim of achieving international environmental objectives at ‘least-cost’, the recent experience offers some valuable lessons. Specifically, in relation to the accuracy of energy projections and assumptions of other relevant variables in the modelling process. This paper considers these lessons and opens a discussion on the role of more adaptable mechanisms for the ongoing management of international agreements with long-term compliance horizons. 相似文献
68.
Serge I. P. Stalpers André R. van Amstel Rob B. Dellink Ivo Mulder Saskia E. Werners Carolien Kroeze 《Mitigation and Adaptation Strategies for Global Change》2008,13(4):359-378
This article discusses an approach for identification and evaluation of short-term greenhouse gas (GHG) emission reduction
options in firms. The approach is based on lessons learnt from a project using Participatory Integrated Assessment (PIA) and
builds on the idea that effective public climate policy for firms requires options that have support from stakeholders and
are practically feasible. Scenarios are used to provide a link with short-term policy developments and a model assists to
communicate quantitative effects of options to participating stakeholders. Our approach can be seen as a first step towards
a framework that meets the need for more systematic approaches to PIAs identifying effective public policies for short-term
GHG emission reduction options in firms. In order to identify effective options for non-carbon dioxide GHG emission reductions,
our approach has been applied to Dutch dairy farms, after which it has been refined. The case study suggests that our approach
can provide balance between practical, context specific issues and scientific-theoretical aspects, thereby avoiding common
pitfalls of participatory research projects to focus too much on either theory or practical issues.
相似文献
Serge I. P. StalpersEmail: |
69.
Paul?WoodcockEmail author David?P.?Edwards Rob?J.?Newton Felicity?A.?Edwards Chey?Vun?Khen Simon?H.?Bottrell Keith?C.?Hamer 《Die Naturwissenschaften》2012,99(4):275-283
Nitrogen isotope signatures (δ15N) provide powerful measures of the trophic positions of individuals, populations and communities. Obtaining reliable consumer
δ15N values depends upon controlling for spatial variation in plant δ15N values, which form the trophic ‘baseline’. However, recent studies make differing assumptions about the scale over which
plant δ15N values vary, and approaches to baseline control differ markedly. We examined spatial variation in the δ15N values of plants and ants sampled from eight 150-m transects in both unlogged and logged rainforests. We then investigated
whether ant δ15N values were related to variation in plant δ15N values following baseline correction of ant values at two spatial scales: (1) using ‘local’ means of plants collected from
the same transect and (2) using ‘global’ means of plants collected from all transects within each forest type. Plant δ15N baselines varied by the equivalent of one trophic level within each forest type. Correcting ant δ15N values using global plant means resulted in consumer values that were strongly positively related to the transect baseline,
whereas local corrections yielded reliable estimates of consumer trophic positions that were largely independent of transect
baselines. These results were consistent at the community level and when three trophically distinct ant subfamilies and eight
abundant ant species were considered separately. Our results suggest that assuming baselines do not vary can produce misleading
estimates of consumer trophic positions. We therefore emphasise the importance of clearly defining and applying baseline corrections
at a scale that accounts for spatial variation in plant δ15N values. 相似文献
70.
Sílvia?SantosEmail author Joana?F.?M.?F.?Cardoso Valeska?Borges Rob?Witbaard Pieternella?C.?Luttikhuizen Henk?W.?van der?Veer 《Marine Biology》2012,159(3):601-611
This study analyzed the isotopic profiles of four aragonitic shells of Scrobicularia plana in conjunction with measured seawater temperatures and salinities. Comparison of δ18OSHELL with expected values revealed fractionation of δ18O in near equilibrium with the ambient environment. Growth cessation occurred between November and March. Carbonate deposition
stopped when temperatures were <12°C. Analysis of δ13CSHELL values suggested that carbon in the shell does not reflect the DIC in ambient water, likely due to the incorporation of metabolic
carbon. An ontogenetic trend of increasing δ13C values over time was observed, likely related to changes in metabolic activity. Annual growth patterns were inferred from
δ18OSHELL profiles and compared with internal and external growth lines. Estimations of age based on external lines were unreliable,
resulting in overestimation of age and underestimation of growth rates, likely due to the disturbance lines being wrongly
identified as annual. Analysis of internal lines may lead to over- or underestimation of age and was more reliable in recent
portions of the shell. 相似文献