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191.
Many animal societies contain few breeders and many helpers. In some species, individuals can become either helpers or breeders,
and breeding is often restricted to high rankers in a dominance hierarchy. In social Hymenoptera with no morphological queen
caste, all females have the potential to become dominant and reproduce. In our model, females involved in the hierarchy do
not work and gain direct fitness if they become alpha following death of the current alpha, while females not in the hierarchy
gain indirect fitness by working. Using an inclusive-fitness model combined with models of alpha replacement in slightly different
types of near-linear hierarchies, we determined the critical rank (i.e., optimal hierarchy length) for which the gain in fitness
by entering the hierarchy as a hopeful reproductive equals the cost caused by a reduced worker force. High relatedness decreases
the hierarchy length by lowering the potential benefit of entering the hierarchy. In contrast, large colony size increases
the hierarchy length because the cost of each non-working high ranker is relatively lower. The model predicts a hierarchy
of five workers in the queenless ant Dinoponera quadriceps, close to empirical data which show that in a colony of about 100 females, the top 5 carry out 72.8% of the aggressive interactions.
The model is also used to make several testable predictions about the effect on hierarchy length of (1) variation in colony
size and (2) variation in worker reproductive options between species of the queenless ants genus Diacamma.
Received: 16 March 1999 / Received in revised form: 30 June 1999 / Accepted: 11 July 1999 相似文献
192.
Pelfrêne Aurélie Sahmer Karin Waterlot Christophe Douay Francis 《Environmental science and pollution research international》2019,26(20):20107-20120
Environmental Science and Pollution Research - Although growing vegetables in urban gardens has several benefits, some questions in relation with the safety of foods remain when the self-production... 相似文献
193.
Zvomuya F Helgason BL Larney FJ Janzen HH Akinremi OO Olson BM 《Journal of environmental quality》2006,35(3):928-937
Prediction of phosphorus (P) availability from soil-applied composts and manure is important for agronomic and environmental reasons. This study utilized chemical properties of eight composted and two non-composted beef cattle (Bos taurus) manures to predict cumulative phosphorus uptake (CPU) during a 363-d controlled environment chamber bioassay. Ten growth cycles of canola (Brassica napus L.) were raised in pots containing 2 kg of a Dark Brown Chernozemic clay loam soil (fine-loamy, mixed, Typic Haploboroll) mixed with 0.04 kg of the amendments. Inorganic P fertilizer (KH2PO4) and an unamended control were included for comparison. All treatments received a nutrient solution containing an adequate supply of all essential nutrients, except P, which was supplied by the amendments. Cumulative P uptake was similar for composted (74 mg kg-1 soil) and non-composted manures (60 mg kg-1 soil) and for the latter and the fertilizer (40 mg kg-1 soil). However, the CPU was significantly higher for organic amendments than the control (24 mg kg-1 soil) and for composted manure than the fertilizer. Apparent phosphorus recovery (APR) from composted manure (24%) was significantly lower than that from non-composted manure (33%), but there was no significant difference in APR between the organic amendments and the fertilizer (27%). Partial least squares (PLS) regression indicated that only two parameters [total water-extractable phosphorus (TPH2O) and total phosphorus (TP) concentration of amendments] were adequate to model amendment-derived cumulative phosphorus uptake (ACPU), explaining 81% of the variation in ACPU. These results suggest that P availability from soil-applied composted and non-composted manures can be adequately predicted from a few simple amendment chemical measurements. Accurate prediction of P availability and plant P recovery may help tailor manure and compost applications to plant needs and minimize the buildup of bioavailable P, which can contribute to eutrophication of sensitive aquatic systems. 相似文献
194.
Francis Joseph Eseigbe Victoria Funmilayo Doherty Temitope Olawunmi Sogbanmu Adebayo Akeem Otitoloju 《Environmental monitoring and assessment》2013,185(3):2189-2196
This study investigated the biomarker responses of the earthworm, Eudrilus eugeniae, exposed to sublethal concentrations of benzene, toluene and xylene (BTX) for a time span of 28 days. Lipid peroxidation (LPO) and histopathological alterations were examined. Toxicological evaluations of BTX were carried out against E. eugeniae. On the basis of the 96-h LC50 value, xylene (1.212 mg/kg) was found to be the most toxic followed by toluene (1.335 mg/kg) and benzene (1.896 mg/kg) was the least toxic. The exposure of earthworms to sublethal concentrations (1/10th and 1/100th of 96 h LC50) of BTX premixed with the substrate (loamy and humus soil) induced pathological changes in the clitella such as severe lesion, necrosis and dark brown pigments. The result of the lipid peroxidation assay showed a significant increase in oxidative damage with LPO values ranging from 2.58–7.8 nM/g in exposed animals when compared to 0.07 nM/g in the control group. The findings from this study suggest the use of LPO and histopathology as useful biomarkers of exposure for early detection of petroleum related stress in terrestrial ecosystems 相似文献
195.
Patterson PL Coulston JW Roesch FA Westfall JA Hill AD 《Environmental monitoring and assessment》2012,184(3):1423-1433
Nonresponse caused by denied access and hazardous conditions are a concern for the USDA Forest Service, Forest Inventory and
Analysis (FIA) program, whose mission is to quantify status and trends in forest resources across the USA. Any appreciable
amount of nonresponse can cause bias in FIA’s estimates of population parameters. This paper will quantify the magnitude of
nonresponse and describe the mechanisms that result in nonresponse, describe and qualitatively evaluate FIA’s assumptions
regarding nonresponse, provide a recommendation concerning plot replacement strategies, and identify appropriate strategies
to pursue that minimize bias. The nonresponse rates ranged from 0% to 21% and differed by land owner group; with denied access
to private land the leading cause of nonresponse. Current FIA estimators assume that nonresponse occurs at random. Although
in most cases this assumption appears tenable, a qualitative assessment indicates a few situations where the assumption is
not tenable. In the short-term, we recommend that FIA use stratification schemes that make the missing at random assumption
tenable. We recommend the examination of alternative estimation techniques that use appropriate weighting and auxiliary information
to mitigate the effects of nonresponse. We recommend the replacement of nonresponse sample locations not be used. 相似文献
196.
Informational constraints can be an important limitation on the accuracy of recognition. One potential constraint is the use
of recognition information from the same sources in multiple discriminatory contexts. Worker wood ants, Formica fusca, discriminate eggs based on their maternal sources of origin in two main contexts: recognition of eggs laid by nestmate versus
non-nestmate queens and recognition of worker-laid versus queen-laid eggs. We manipulated the experience of F. fusca workers in laboratory colonies to both worker-laid and queen-laid eggs by transferring eggs between colonies in order to
investigate whether these two contexts of egg discrimination are independent. Experience of non-nestmate queen-laid eggs significantly
increased worker acceptance of both familiar (18% accepted) and unfamiliar (10%) queen-laid eggs compared to control workers
without experience of eggs other than those laid by their own colony’s queen (2%). In contrast, worker acceptance of worker-laid
eggs was not affected by variation in the egg experience of workers (14% in workers from control colonies exposed only to
eggs from their own colony’s queen versus 19% and 17% in workers from colonies which had received eggs laid by either a non-nestmate
queen or nestmate workers, respectively). Our results suggest that these two recognition contexts do not strongly constrain
each other and are different in their ontogeny. In particular, worker-laid eggs are universally discriminated against by workers
from colonies with a queen whatever the egg experience of the workers, while non-nestmate queen-laid eggs are strongly discriminated
against only by workers without experience of eggs laid by more than one queen. 相似文献
197.
We examined the effects of the ionic liquids (ILs), 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6], N-ethylpyridinium tetrafluoroborate [EtPy][BF4], and N-ethylpyridinium trifluoroacetate [EtPy][CF3COO] on Pseudomonas fluorescens, a ubiquitous soil bacterium. In the presence of 0.5- and 1% of [BMIM][PF6] or [EtPy][CF3COO] the growth of bacteria was inhibited, whereas exposing them to 1% [EtPy][BF4] increased the lag period wherein bacteria adapt to growth conditions before continuing to grow. However, at higher concentrations (5% and 10%), no growth was observed. The inhibitory effects were evident by a decrease in the optical density of the culture, a decline in the consumption of the carbon source, citric acid, and a change in the size of the bacterium. At concentrations below 1%, [EtPy][BF4] was metabolized by P. fluorescens in the presence of citric acid. Oxidation of the side alkyl-chain of [EtPy][BF4] caused the accumulation of N-hydroxylethylpyridinium and pyridinium as major degradation products. 相似文献
198.
17β-estradiol (E2) is a natural estrogenic hormone found in animal manure and urine, which may cause endocrine disruption in sensitive organisms. 17β-Estradiol has been widely detected in the environment, and animal agriculture may be an important source. The objectives of this study were to investigate the potential sources and/or spatial and temporal characteristics contributing to detections of E2 at the farm-scale. Soil cores, segmented into 0.15 m increments, were taken down to the water table from four locations (three potential E2 sources and one control) at or around a swine (Sus scrofa domesticus) farm on five different dates between 2006 and 2007. Estradiol was quantified in the soil-water extracts using liquid chromatography-with tandem mass spectrometry (LC/MS/MS) analysis. Estradiol detections were widespread and found in 128 out of 345 extractions (37%). Concentrations ranged from 0 to 1910 ng L−1 (porewater equivalents). A location that received field application of manure had significantly lower E2 concentrations compared to other locations. Also, the spring 2007 E2 concentrations were significantly higher than all other sample dates, perhaps related to climatic and hydrological events. Results suggested E2 was not directly related to manure sources, but was widespread in this environment. Where E2 was detected, highest concentrations favored the upper profile, while the greatest frequency of detections was in the lower profile and near the water table. Detections of E2 were associated with high organic mater contents in the upper profile and high sand contents in the lower profile. The study suggests that E2 is widespread in some soil environments, raising questions as to the source and mechanisms that facilitate its transport and mobility. 相似文献
199.
Lopareva-Pohu A Verdin A Garçon G Lounès-Hadj Sahraoui A Pourrut B Debiane D Waterlot C Laruelle F Bidar G Douay F Shirali P 《Environmental pollution (Barking, Essex : 1987)》2011,159(6):1721-1729
Due to anthropogenic activities, large extends of soils are highly contaminated by Metal Trace Element (MTE). Aided phytostabilisation aims to establish a vegetation cover in order to promote in situ immobilisation of trace elements by combining the use of metal-tolerant plants and inexpensive mineral or organic soil amendments. Eight years after Coal Fly Ash (CFA) soil amendment, MTE bioavailability and uptake by two plants, Lolium perenne and Trifolium repens, were evaluated, as some biological markers reflecting physiological stress. Results showed that the two plant species under study were suitable to reduce the mobility and the availability of these elements. Moreover, the plant growth was better on CFA amended MTE-contaminated soils, and the plant sensitivity to MTE-induced physiological stress, as studied through photosynthetic pigment contents and oxidative damage was lower or similar. In conclusion, these results supported the usefulness of aided phytostabilisation of MTE-highly contaminated soils. 相似文献
200.
Mark Appiah Dominic Blay Lawrence Damnyag Francis K. Dwomoh Ari Pappinen Olavi Luukkanen 《Environment, Development and Sustainability》2009,11(3):471-487
In Ghana, forests provide many products on which the local population subsists. However, these resources are depleting due
to a variety of factors including agricultural expansion and over-exploitation of forest resources. This paper presents an
analysis of the level of local dependence on forest resources and its implications for forest management in Ghana. The paper
also outlines the causes of continuing deforestation in the studied region from the perspective of the local residents and
discusses what role they could play in addressing the problem. The aim is to share more light on the current causes of deforestation
and make suggestions for improved community-based forest management practices that could help to reduce deforestation. Primary
data was collected through personal interviews and focus group discussions with 431 household heads randomly selected from
three Forest Districts in Ghana. The survey showed that income from agriculture constituted 60% of the average total rural
household income. Forest income provided 38% of total household income, and off-farm income 2%. The four most highly ranked
causes of deforestation are poverty-driven agriculture, lack of alternative rural wage employment other than farming, household
population levels, and conflict in traditional land practices. This shows a shift in the view of local people who in the past
were quick to blame logging companies and government policies for deforestation. The majority of the respondents depended
on wild animals like snail, bush meat, wild honey and wild and cultivated vegetables. Given the reasons for deforestation,
much thought needs to go into agroforestry practices (e.g. snail farming, bee keeping, fish farming, and vegetable production)
in efforts to reduce deforestation, which are currently less promoted.
Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue. 相似文献