Breaking the ice: the introduction of biofouling organisms to Antarctica on vessel hulls          下载免费PDF全文

Kevin A. Hughes  Gail V. Ashton 《水产资源保护:海洋与淡水生态系统》2017,27(1):158-164

Progress and challenges in freshwater conservation planning     

Jeanne L. Nel  Dirk J. Roux  Robin Abell  Peter J. Ashton  Richard M. Cowling  Jonathan V. Higgins  Michele Thieme  Joshua H. Viers 《水产资源保护:海洋与淡水生态系统》2009,19(4):474-485

• 1. Freshwater ecosystems and their associated biota are among the most endangered in the world. This, combined with escalating human pressure on water resources, demands that urgent measures be taken to conserve freshwater ecosystems and the services they provide. Systematic conservation planning provides a strategic and scientifically defensible framework for doing this.
• 2. Pioneered in the terrestrial realm, there has been some scepticism associated with the applicability of systematic approaches to freshwater conservation planning. Recent studies, however, indicate that it is possible to apply overarching systematic conservation planning goals to the freshwater realm although the specific methods for achieving these will differ, particularly in relation to the strong connectivity inherent to most freshwater systems.
• 3. Progress has been made in establishing surrogates that depict freshwater biodiversity and ecological integrity, developing complementarity‐based algorithms that incorporate directional connectivity, and designing freshwater conservation area networks that take cognizance of both connectivity and implementation practicalities.
• 4. Key research priorities include increased impetus on planning for non‐riverine freshwater systems; evaluating the effectiveness of freshwater biodiversity surrogates; establishing scientifically defensible conservation targets; developing complementarity‐based algorithms that simultaneously consider connectivity issues for both lentic and lotic water bodies; developing integrated conservation plans across freshwater, terrestrial and marine realms; incorporating uncertainty and dynamic threats into freshwater conservation planning; collection and collation of scale‐appropriate primary data; and building an evidence‐base to support improved implementation of freshwater conservation plans.

Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

The demise of the Nile crocodile (Crocodylus niloticus) as a keystone species for aquatic ecosystem conservation in South Africa: The case of the Olifants River     

Peter J. Ashton 《水产资源保护:海洋与淡水生态系统》2010,20(5):489-493

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Anti‐inflammatory drugs decrease infection of brain endothelial cells with EHV‐1 in vitro          下载免费PDF全文

L. S. Goehring  K. Brandes  L. V. Ashton  L. A. Wittenburg  F. J. Olea‐Popelka  D. P. Lunn  G. Soboll Hussey 《Equine veterinary journal》2017,49(5):629-636

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Phytoremediation Potential of Vetiver Grass (<Emphasis Type="Italic">Vetiveria zizanioides</Emphasis>) for Treatment of Metal-Contaminated Water     

Ashton Lim Suelee  Sharifah Nur Munirah Syed Hasan  Faradiella Mohd Kusin  Ferdaus Mohamat Yusuff  Zelina Zaiton Ibrahim 《Water, air, and soil pollution》2017,228(4):158

Phytoremediation using vetiver grass (Vetiveria zizanioides) has been regarded as an effective technique for removing contaminants in polluted water. This study was conducted to assess the removal efficiency of heavy metals (Cu, Fe, Mn, Pb, Zn) using vetiver grass (VG) at different root lengths and densities and to determine metals uptake rate by plant parts (root and shoot) between treatments (low and high concentration). Removal efficiency for heavy metals in water by VG is ranked in the order of Fe>Pb>Cu>Mn>Zn. Results showed that VG was effective in removing all the heavy metals, but removals greatly depend on root length, plant density and metal concentration. Longer root length and higher density showed greater removals of heavy metals due to increased surface area for metal absorption by plant roots. Results also demonstrated significant difference of heavy metals uptake in plant parts at different concentrations indicating that root has high tolerance towards elevated concentration of heavy metals. However, the effects were less significant in plant shoot suggesting that metals uptake were generally higher in root than in shoot. The findings have shown potential of VG in phytoremediation for heavy metals removal in water thus providing significant implication for treatment of metal-contaminated water.  相似文献   

Local and regional environmental variation influences the growth of tropical trees in selection trials in the Republic of Panama     

Andrew Park  Michiel van Breugel  Mark S. Ashton  Mark Wishnie  Emilio Mariscal  José Deago  Diogenes Ibarra  Norma Cedeño  Jefferson S. Hall 《Forest Ecology and Management》2010

Native Neotropical trees are being increasingly planted for restoration purposes and timber production, but we lack species-specific data on growth responses to different regional climates and local environmental variation. We used regression trees and variance components to quantify the effects of within- and among-site environmental variation on the basal area (BA) of 21 Neotropical and two exotic tree species at three selection trials in the Republic of Panama. Sites represented distinct regional climates in which annual rainfall varied from 1100 to 2226 mm, with dry seasons of 4.1–6.7 months. Local environmental variables included measures of slope steepness and position, soil texture, soil color, and indicators of soil condition, such as subsoil rockiness.  相似文献   

Addressing the interplay of poverty and the ecology of landscapes: a Grand Challenge Topic for landscape ecologists?     

Bryan C. Pijanowski  Louis R. Iverson  C. Ashton Drew  Henry N. N. Bulley  Jeanine M. Rhemtulla  Michael C. Wimberly  Annett Bartsch  Jian Peng 《Landscape Ecology》2010,25(1):5-16

We argue for the landscape ecology community to adopt the study of poverty and the ecology of landscapes as a Grand Challenge Topic. We present five areas of possible research foci that we believe that landscape ecologists can join with other social and environmental scientists to increase scientific understanding of this pressing issue: (1) scale and poverty; (2) landscape structure and human well-being; (3) social and ecological processes linked to spatial patterns in landscapes; (4) conservation and poverty, and (5) applying the landscape ecologist’s toolkit. A brief set of recommendations for landscape ecologists is also presented. These include the need to utilize broad frameworks that integrate social and ecological variables, build capacity to do this kind of work through the development of strong collaborations of researchers in developed and developing countries, create databases in international locations where extreme poverty exists, and create a new generation of researchers capable of addressing this pressing social and environmental issue.  相似文献   

Desktop classification of inland wetlands for systematic conservation planning in data‐scarce countries: mapping wetland ecosystem types,disturbance indices and threatened species associations at country‐wide scale          下载免费PDF全文

Heidi van Deventer  Jeanne Nel  Namhla Mbona  Nancy Job  Justine Ewart‐Smith  Kate Snaddon  Ashton Maherry 《水产资源保护:海洋与淡水生态系统》2016,26(1):57-75

Relationships between bole and crown size for young urban trees in the northeastern USA     

Blake Troxel  Max Piana  Mark S. Ashton  Colleen Murphy-Dunning 《Urban Forestry & Urban Greening》2013,12(2):144-153

Knowledge of allometric equations can enable urban forest managers to meet desired economic, social, and ecological goals. However, there remains limited regional data on young tree growth within the urban landscape. The objective of this study is to address this research gap and examine interactions between age, bole size and crown dimensions of young urban trees in New Haven, CT, USA to identify allometric relationships and generate predictive growth equations useful for the region. This study examines the 10 most common species from a census of 1474 community planted trees (ages 4–16). Regressions were applied to relate diameter at breast height (dbh), age (years since transplanting), tree height, crown diameter and crown volume. Across all ten species each allometric relationship was statistically (p < 0.001) significant at an α-level of 0.05. Consistently, shade trees demonstrated stronger relationships than ornamental trees. Crown diameter and dbh displayed the strongest fit with eight of the ten species having an R² > 0.70. Crown volume exhibited a good fit for each of the shade tree species (R² > 0.85), while the coefficients of determination for the ornamentals varied (0.38 < R² < 0.73). In the model predicting height from dbh, ornamentals displayed the lowest R² (0.33 < R² < 0.55) while shade trees represented a much better fit (R² > 0.66). Allometric relationships can be used to develop spacing guidelines for commonly planted urban trees. These correlations will better equip forest managers to predict the growth of urban trees, thereby improving the management and maintenance of New England's urban forests.  相似文献   

Infection of central nervous system endothelial cells by cell-associated EHV-1     

Goehring LS  Hussey GS  Ashton LV  Schenkel AR  Lunn DP 《Veterinary microbiology》2011,148(2-4):389-395

Infection with equine herpesvirus-1 (EHV-1) causes respiratory disease, late-term abortions and equine herpesvirus myeloencephalitis (EHM). Our understanding of EHM pathogenesis is limited except for the knowledge that EHV-1 infected, circulating peripheral blood mononuclear cells (PBMC) transport virus to the central nervous system vasculature causing endothelial cell infection leading to development of EHM. Our objective was to develop a model of CNS endothelial cell infection using EHV-1 infected, autologous PBMC. PBMCs, carotid artery and brain endothelial cells (EC) from 14 horses were harvested and grown to confluency. PBMC or ConA-stimulated PBMCs (ConA-PBMCs) were infected with EHV-1, and sedimented directly onto EC monolayers ('contact'), or placed in inserts on a porous membrane above the EC monolayer ('no contact'). Cells were cultured in medium with or without EHV-1 virus neutralizing antibody. Viral infection of ECs was detected by cytopathic effect. Both brain and carotid artery ECs became infected when cultured with EHV-1 infected PBMCs or ConA-PBMCs, either in direct contact or no contact: infection was higher in carotid artery than in brain ECs, and when using ConA-PBMCs compared to PBMCs. Virus neutralizing antibody eliminated infection of ECs in the no contact model only. This was consistent with cell-to-cell spread of EHV-1 infection from leucocytes to ECs, demonstrating the importance of this mode of infection in the presence of antibody, and the utility of this model for study of cellular interactions in EHV-1 infection of ECs.  相似文献