The first results of female preference and chosen male mating success in a new model organism, the pentamorphic livebearing fish, Poecilia parae, are presented. Poecilia parae is a relative of the guppy, P. reticulata, and is assumed to have similar reproductive behavior. We tested the hypothesis that P. parae females, like female guppies, prefer caretenoid colored males as mates. Here we show that the time a female spent with males was significantly greater for carotenoid coloration in red and yellow melanzona, but time with these two morphs did not differ. The preferred red and yellow males mated significantly more often with their choosing females than did the non-preferred blue and parae males. The few blue melanzona and parae males that mated did so without performing courtship displays. Some females mated with all phenotypes including immaculata males during open group trials. Female P. parae clearly preferred males with carotenoid coloration, thereby corroborating the hypothesis. Alternative male mating tactics by blue melanzona, parae, and immaculata morphs and promiscuous mating by females also resembled features of reproductive behaviors exhibited by guppies. 相似文献
Sub-Saharan Africa lags far behind other regions in terms of the implementation of Clean Development Mechanism (CDM) projects
due to several reasons. One of the reasons is a general perception that, since the region contributes very little to global
GHG emissions, it also offers few opportunities to reduce these emissions. Using a bottom-up approach, this study investigates
the technical potential of reducing GHG emissions from the energy sector in Sub-Saharan Africa through the CDM. The study
finds that sub-Saharan Africa could develop 3,227 CDM projects, including 361 programs of activities, which could reduce approximately
9.8 billion tons of GHG emissions during the CDM project cycles. The study also estimates that the realization of this CDM
potential could significantly enhance sustainable development in the region as it would attract more than US200 billionininvestmentandcouldgenerateUS200 billion in
investment and could generate US98 billion of CDM revenue at a CER price of US$10/tCO2. Another notable finding of the study
is that the realization of this CDM potential could supply clean electricity by doubling the current capacity and thereby
providing access of electricity to millions of people in the region. However, realization of this CDM potential is severely
constrained by a number of financial, technical, regulatory and institutional barriers. 相似文献
In 1993 the Swiss agricultural policy was revised with – amongst other goals – the objective of improving the environmental performance of agriculture. A voluntary agri-environmental scheme to promote integrated production (IP) was introduced. In 1999 the IP standards were integrated in cross compliance requirements and termed Proof of Ecological Performance (PEP). We evaluated the effectiveness of this policy in terms of reducing diffuse nitrogen (N) and phosphorus (P) pollution of ground and surface water. We combined monitoring schemes covering the reference period from before the introduction of IP/PEP (1990–1992) with the evaluation of cause/effect relationships in selected case-study areas. The evaluation showed an overall reduction of diffuse N and P pollution from agriculture even though some goals were not reached. Nitrate leaching declined, but only a 3–4 mg L−1 reduction was observed rather than the intended decrease of 5 mg L−1. The P pollution of surface waters from agriculture decreased by only 10–30% instead of 50%. The intended reduction of the nitrogen surplus of Swiss agriculture by 33% was not attained, but the P surplus of Swiss agriculture was more than halved. IP/PEP practices that improved N and P management included reduced N and P fertiliser inputs and pig and poultry feedstuffs with reduced N and P contents, both of which are a consequence of the requirement of equilibrated farm nutrient balances, as well as increased use of cover cropping and of conservation tillage systems. 相似文献
To be effective, climate change adaptation needs to be mainstreamed across multiple sectors and greater policy coherence is essential. Using the cases of Malawi, Tanzania and Zambia, this paper investigates the extent of coherence in national policies across the water and agriculture sectors and to climate change adaptation goals outlined in national development plans. A two-pronged qualitative approach is applied using Qualitative Document Analysis of relevant policies and plans, combined with expert interviews from non-government actors in each country. Findings show that sector policies have differing degrees of coherence on climate change adaptation, currently being strongest in Zambia and weakest in Tanzania. We also identify that sectoral policies remain more coherent in addressing immediate-term disaster management issues of floods and droughts rather than longer-term strategies for climate adaptation. Coherence between sector and climate policies and strategies is strongest when the latter has been more recently developed. However to date, this has largely been achieved by repackaging of existing sectoral policy statements into climate policies drafted by external consultants to meet international reporting needs and not by the establishment of new connections between national sectoral planning processes. For more effective mainstreaming of climate change adaptation, governments need to actively embrace longer-term cross-sectoral planning through cross-Ministerial structures, such as initiated through Zambia’s Interim Climate Change Secretariat, to foster greater policy coherence and integrated adaptation planning. 相似文献
With the increasing concern about the serious global energy crisis and high energy consumption during high content solid wastes (HCSWs) treatment, microbial fuel cell (MFC) has been recognized as a promising resource utilization approach for HCSW stabilization with simultaneous electrical energy recovery. In contrast to the conventional HCSW stabilization processes, MFC has its unique advantages such as direct bio-energy conversion in a single step and mild reaction conditions (viz., ambient temperature, normal pressure, and neutral pH). This review mainly introduces some important aspects of electricity generation from HCSWand its stabilization in MFC, focusing on: (1) MFCs with different fundamentals and configurations designed and constructed to produce electricity from HCSW; (2) performance of wastes degradation and electricity generation; (3) prospect and deficiency posed by MFCs with HCSWas substrates. To date, the major drawback of MFCs fueled by HCSW is the lower power output than those using simple substrates. HCSW hydrolysis and decomposition would be a major tool to improve the performance of MFCs. The optimization of parameters is needed to push the progress of MFCs with HCSW as fuel.
Feral swine are estimated to annually cost hundreds of millions of dollars in economic loss to property and agriculture in the USA, while their ecological consequences remain largely unmeasured. Using submeter-accurate Global Positioning System technology over a multiyear project, we are quantifying in a novel way the spatial and temporal attributes of swine rooting damage within 587 ha of ecologically sensitive wetland plant communities at Avon Park Air Force Range in south-central Florida. We delineated damage polygons from 0.0023 to 4,335 m2 and were able to document recurrent damage through time at most sites during each assessment. For each polygon, we also estimated the age of damage and assigned to it a severity index, qualities of the rooting in which we detected changes in proportions over time. Spatially explicit damage assessments at fine scales conducted over several years can assist land managers in determining effects of rooting on rare plant populations, and will allow investigators to hypothesize what factors are driving patterns of this disturbance across ecologically sensitive plant communities. 相似文献
Today, a variety of different approaches to the recovery of phosphorus from wastewater, sludge, and sludge ash exist. These approaches differ basically by the origin of the used matter (wastewater, sludge liquor, fermented or nonfermented sludge ash) and the process (precipitation, wet-chemical extraction, and thermal treatment). To rate them according to their characteristics, the latter were phrased as hypotheses and subjected to an international expert survey. The survey showed that phosphorus recovery is expected to become an established process over the next 20 years in industrialized countries for economic reasons. A decisive aspect in this regard will be the quality of the produced fertilizer. Simple technologies such as the recovery from sludge liquor seem to be preferred. If sludge is incinerated, phosphorus recycling from ash then becomes more interesting and has to be considered. Phosphorus recovery and source-separating sanitation technologies are more appropriate for industrialized countries than for developing countries. Because the growing awareness of environmental issues will prevent sludge from being used agriculturally in an increasing number of countries in the next decade, the market potential for nutrient recovery technologies will increase in the immediate future. 相似文献
We examine the advantages and disadvantages of a methodological framework designed to analyze the poorly understood relationships
between the ecosystem properties of large portions of land, and their capacities (stocks) to provide goods and services (flows).
These capacities (stocks) are referred to as landscape functions. The core of our assessment is a set of expert- and literature-driven
binary links, expressing whether specific land uses or other environmental properties have a supportive or neutral role for
given landscape functions. The binary links were applied to the environmental properties of 581 administrative units of Europe
with widely differing environmental conditions and this resulted in a spatially explicit landscape function assessment. To
check under what circumstances the binary links are able to replace complex interrelations, we compared the landscape function
maps with independently generated continent-wide assessments (maps of ecosystem services or environmental parameters/indicators).
This rigorous testing revealed that for 9 out of 15 functions the straightforward binary links work satisfactorily and generate
plausible geographical patterns. This conclusion holds primarily for production functions. The sensitivity of the nine landscape
functions to changes in land use was assessed with four land use scenarios (IPCC SRES). It was found that most European regions
maintain their capacity to provide the selected services under any of the four scenarios, although in some cases at other
locations within the region. At the proposed continental scale, the selected input parameters are thus valid proxies which
can be used to assess the mid-term potential of landscapes to provide goods and services. 相似文献
Western European landscapes have drastically changed since the 1950s, with agricultural intensifications and the spread of
urban settlements considered the most important drivers of this land-use/land-cover change. Losses of habitat for fauna and
flora have been a direct consequence of this development. In the present study, we relate butterfly occurrence to land-use/land-cover
changes over five decades between 1951 and 2000. The study area covers the entire Swiss territory. The 10 explanatory variables
originate from agricultural statistics and censuses. Both state as well as rate was used as explanatory variables. Species
distribution data were obtained from natural history collections. We selected eight butterfly species: four species occur
on wetlands and four occur on dry grasslands. We used cluster analysis to track land-use/land-cover changes and to group communes
based on similar trajectories of change. Generalized linear models were applied to identify factors that were significantly
correlated with the persistence or disappearance of butterfly species. Results showed that decreasing agricultural areas and
densities of farms with more than 10 ha of cultivated land are significantly related with wetland species decline, and increasing
densities of livestock seem to have favored disappearance of dry grassland species. Moreover, we show that species declines
are not only dependent on land-use/land-cover states but also on the rates of change; that is, the higher the transformation rate from small to large farms, the higher the loss of dry grassland species.
We suggest that more attention should be paid to the rates of landscape change as feasible drivers of species change and derive
some management suggestions. 相似文献