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11.
Lugo-Ospina A Dao TH Van Kessel JA Reeves JB 《Environmental pollution (Barking, Essex : 1987)》2005,135(1):155-162
Nutrients in animal manure are valuable inputs in agronomic crop production. Rapid and timely information about manure nutrient content are needed to minimize the risks of phosphorus (P) over-application and losses of dissolved P (DP) in runoff from fields treated with manure. We evaluated the suitability of a commercial hand-held reflectometer, a hydrometer, and an electrical conductivity (EC) meter for determining DP and total P (TP) in dairy manures. Bulk samples (n = 107) collected from farms across CT, MD, NY, PA, and VA were highly variable in total solids (TS) concentration, ranging from 11 to 213gL(-1), in suspensions' pH (6.3-9.2), and EC (6.2-53.3 dS m(-1)). Manure DP concentrations measured using the RQFlex reflectometer (RQFlex-DP(s)) were related to molybdate-reactive P (MRP(s)) concentrations as follows: RQFlex-DP(s) = 0.471 x MRP(s) + 1102 (r2 = 0.29). Inclusion of pH and squared-pH terms improved the prediction of manure DP from RQFlex results (r2 = 0.66). Excluding five outlier samples that had pH < or = 6.9 the coefficient of determination (r2) for the MRP(s) and RQFlex-DP(s) relationship was 0.83 for 95% of the samples. Manure TS were related to hydrometer specific gravity readings (r2 = 0.53) that were in turn related to TP (r2 = 0.34), but not to either RQFlex-DP or MRP. Relationships between suspensions' EC and DP or TP were non-significant. Therefore, the RQFlex method is the only viable option for on-site quick estimates of DP that can be made more robust when complemented with TS and pH measurements. The DP quick test can provide near real-time information on soluble manure nutrient content across a wide range of handling and storage conditions on dairy farms and quick estimates of potential soluble P losses in runoff following land applications of manure. 相似文献
12.
A spatially explicit estimate of the prewhaling abundance of the endangered North Atlantic right whale 下载免费PDF全文
Sophie Monsarrat M. Grazia Pennino Tim D. Smith Randall R. Reeves Christine N. Meynard David M. Kaplan Ana S.L. Rodrigues 《Conservation biology》2016,30(4):783-791
The North Atlantic right whale (NARW) (Eubalaena glacialis) is one of the world's most threatened whales. It came close to extinction after nearly a millennium of exploitation and currently persists as a population of only approximately 500 individuals. Setting appropriate conservation targets for this species requires an understanding of its historical population size, as a baseline for measuring levels of depletion and progress toward recovery. This is made difficult by the scarcity of records over this species’ long whaling history. We sought to estimate the preexploitation population size of the North Atlantic right whale and understand how this species was distributed across its range. We used a spatially explicit data set on historical catches of North Pacific right whales (NPRWs) (Eubalaena japonica) to model the relationship between right whale relative density and the environment during the summer feeding season. Assuming the 2 right whale species select similar environments, we projected this model to the North Atlantic to predict how the relative abundance of NARWs varied across their range. We calibrated these relative abundances with estimates of the NPRW total prewhaling population size to obtain high and low estimates for the overall NARW population size prior to exploitation. The model predicted 9,075–21,328 right whales in the North Atlantic. The current NARW population is thus <6% of the historical North Atlantic carrying capacity and has enormous potential for recovery. According to the model, in June–September NARWs concentrated in 2 main feeding areas: east of the Grand Banks of Newfoundland and in the Norwegian Sea. These 2 areas may become important in the future as feeding grounds and may already be used more regularly by this endangered species than is thought. 相似文献
13.
Role of refugia in recovery from disturbances: Modern fragmented and disconnected river systems 总被引:10,自引:0,他引:10
James R. Sedell Gordon H. Reeves F. Richard Hauer Jack A. Stanford Charles P. Hawkins 《Environmental management》1990,14(5):711-724
Habitats or environmental factors that convey spatial and temporal resistance and/or resilience to biotic communities that
have been impacted by biophysical disturbances may be called refugia. Most refugia in rivers are characterized by extensive
coupling of the main channel with adjacent streamside forests, floodplain features, and groundwater. These habitats operate
at different spatial scales, from localized particles, to channel units such as pools and riffles, to reaches and longer sections,
and at the basin level. A spatial hierarchy of different physical components of a drainage network is proposed to provide
a context for different refugia. Examples of refugia operating at different spatial scales, such as pools, large woody debris,
floodplains, below dams, and catchment basins are discussed. We hope that the geomorphic context proposed for examining refugia
habitats will assist in the conservation of pristine areas and attributes of river systems and also allow a better understanding
of rehabilitation needs in rivers that have been extensively altered. 相似文献
14.
Gill T. Braulik Barbara L. Taylor Gianna Minton Giuseppe Notarbartolo di Sciara Tim Collins Lorenzo Rojas-Bracho Enrique A. Crespo Louisa S. Ponnampalam Michael C. Double Randall R. Reeves 《Conservation biology》2023,37(5):e14090
To understand the scope and scale of the loss of biodiversity, tools are required that can be applied in a standardized manner to all species globally, spanning realms from land to the open ocean. We used data from the International Union for the Conservation of Nature Red List to provide a synthesis of the conservation status and extinction risk of cetaceans. One in 4 cetacean species (26% of 92 species) was threatened with extinction (i.e., critically endangered, endangered, or vulnerable) and 11% were near threatened. Ten percent of cetacean species were data deficient, and we predicted that 2–3 of these species may also be threatened. The proportion of threatened cetaceans has increased: 15% in 1991, 19% in 2008, and 26% in 2021. The assessed conservation status of 20% of species has worsened from 2008 to 2021, and only 3 moved into categories of lesser threat. Cetacean species with small geographic ranges were more likely to be listed as threatened than those with large ranges, and those that occur in freshwater (100% of species) and coastal (60% of species) habitats were under the greatest threat. Analysis of odontocete species distributions revealed a global hotspot of threatened small cetaceans in Southeast Asia, in an area encompassing the Coral Triangle and extending through nearshore waters of the Bay of Bengal, northern Australia, and Papua New Guinea and into the coastal waters of China. Improved management of fisheries to limit overfishing and reduce bycatch is urgently needed to avoid extinctions or further declines, especially in coastal areas of Asia, Africa, and South America. 相似文献
15.
Roberson T Reddy KC Reddy SS Nyakatawa EZ Raper RL Reeves DW Lemunyon J 《Journal of environmental quality》2008,37(2):535-541
Increased CO2 release from soils resulting from agricultural practices such as tillage has generated concerns about contributions to global warming. Maintaining current levels of soil C and/or sequestering additional C in soils are important mechanisms to reduce CO2 in the atmosphere through production agriculture. We conducted a study in northern Alabama from 2003 to 2006 to measure CO2 efflux and C storage in long-term tilled and non-tilled cotton (Gossypium hirsutum L.) plots receiving poultry litter or ammonium nitrate (AN). Treatments were established in 1996 on a Decatur silt loam (clayey, kaolinitic thermic, Typic Paleudults) and consisted of conventional-tillage (CT), mulch-tillage (MT), and no-tillage (NT) systems with winter rye [Secale cereale (L.)] cover cropping and AN and poultry litter (PL) as nitrogen sources. Cotton was planted in 2003, 2004, and 2006. Corn was planted in 2005 as a rotation crop using a no-till planter in all plots, and no fertilizer was applied. Poultry litter application resulted in higher CO2 emission from soil compared with AN application regardless of tillage system. In 2003 and 2006, CT (4.39 and 3.40 micromol m(-2) s(-1), respectively) and MT (4.17 and 3.39 micromol m(-2) s(-1), respectively) with PL at 100 kg N ha(-1) (100 PLN) recorded significantly higher CO2 efflux compared with NT with 100 PLN (2.84 and 2.47 micromol m(-2) s(-1), respectively). Total soil C at 0- to 15-cm depth was not affected by tillage but significantly increased with PL application and winter rye cover cropping. In general, cotton produced with NT conservation tillage in conjunction with PL and winter rye cover cropping reduced CO2 emissions and sequestered more soil C compared with control treatments. 相似文献
16.
The possibility of in situ heavy metal decontamination of polluted soils using crops of metal-accumulating plants 总被引:8,自引:0,他引:8
A.J.M. Baker S.P. McGrath C.M.D. Sidoli R.D. Reeves 《Resources, Conservation and Recycling》1994,11(1-4)
The decontamination of soils and wastes polluted with heavy metals presents one of the most intractable problems for soil clean-up. Present technology relies upon metal extraction or immobilization processes, both of which are expensive and which remove all biological activity in the soil during decontamination. They may only be appropriate for small areas of valuable redevelopment land. In this paper the use of metal-accumulating plants is explored for the removal of metals from superficially-contaminated soils such as those resulting from the long-term application to land of metal-contaminated sewage sludges. Green remediation employs plants native to metalliferous soils with a capacity to bioaccumulate metals such as zinc and nickel to concentrations greater than 2% in the aerial plant dry matter (hyperaccumulators). Growing such plants under intensive crop conditions and harvesting the dry matter is proposed as a possible method of metal removal and for ‘polishing’ contaminated agricultural soils down to metal concentrations below statutory limits. Not only are the biological activity and physical structure of soils maintained but the technique is potentially cheap, visually unobtrusive and offers the possibility of biorecovery of metals. The limitations of the process are reviewed and the future requirements for the development of efficient phytoremediators are outlined. 相似文献
17.
18.
Mark A. Stanaway Kerrie L. Mengersen Robert Reeves 《Environmental and Ecological Statistics》2011,18(3):569-591
Early detection surveillance programs aim to find invasions of exotic plant pests and diseases before they are too widespread
to eradicate. However, the value of these programs can be difficult to justify when no positive detections are made. To demonstrate
the value of pest absence information provided by these programs, we use a hierarchical Bayesian framework to model estimates
of incursion extent with and without surveillance. A model for the latent invasion process provides the baseline against which
surveillance data are assessed. Ecological knowledge and pest management criteria are introduced into the model using informative
priors for invasion parameters. Observation models assimilate information from spatio-temporal presence/absence data to accommodate
imperfect detection and generate posterior estimates of pest extent. When applied to an early detection program operating
in Queensland, Australia, the framework demonstrates that this typical surveillance regime provides a modest reduction in
the estimate that a surveyed district is infested. More importantly, the model suggests that early detection surveillance
programs can provide a dramatic reduction in the putative area of incursion and therefore offer a substantial benefit to incursion
management. By mapping spatial estimates of the point probability of infestation, the model identifies where future surveillance
resources can be most effectively deployed. 相似文献
19.
Peter A. Vadas William E. Jokela Dory H. Franklin Dinku M. Endale 《Journal of the American Water Resources Association》2011,47(4):877-886
Vadas, Peter A., William E. Jokela, Dory H. Franklin, and Dinku M. Endale, 2011. The Effect of Rain and Runoff When Assessing Timing of Manure Application and Dissolved Phosphorus Loss in Runoff. Journal of the American Water Resources Association (JAWRA) 47(4):877‐886. DOI: 10.1111/j.1752‐1688.2011.00561.x Abstract: A significant pathway of nonpoint source, agricultural phosphorus (P) transport is surface runoff, to which surface‐applied manure can contribute. Increasing the time between manure application and the first rain‐runoff event is proposed as a practice to reduce runoff P loss. Few studies have investigated this aspect of manure P loss in runoff, with mixed results. Studies observing a decrease in runoff P as the time between application and the first rain‐runoff attribute the decrease to adsorption of manure P by soil and manure drying effects, but do not consider the effect of storm hydrology on runoff P. We ran the manure P runoff model SurPhos with data from nine published studies that investigated the effect of time between application and the first rain event on runoff P. SurPhos successfully simulated the experimental conditions in the studies and predicted runoff P loss. Simulation results suggest soil adsorption of manure P is not the dominant mechanism that will significantly decrease manure P availability to runoff. Rather, regardless of when the first rain‐runoff event occurs, storm hydrology will significantly affect manure P loss in runoff. Although model scenarios indicate that increasing the time between manure application and the first rain‐runoff event will typically decrease P loss in runoff, runoff P could be equal to or greater 30 days after application than the day after application if a more intense rain and runoff event occurs at the latter date. 相似文献
20.
Near- and mid-infrared diffuse reflectance spectroscopy for measuring soil metal content 总被引:3,自引:0,他引:3
Siebielec G McCarty GW Stuczynski TI Reeves JB 《Journal of environmental quality》2004,33(6):2056-2069
Rapid and nondestructive methods such as diffuse reflectance infrared spectroscopy provide potentially useful alternatives to time-consuming chemical methods of soil metal analysis. To assess the utility of near-infrared reflectance spectroscopy (NIRS) and diffuse mid-infrared reflectance spectroscopy (DRIFTS) for soil metal determination, 70 soil samples from the metal mining region of Tarnowskie Gory (Upper Silesia, Poland) were analyzed by both chemical and spectroscopic methods. Soils represented a wide range of pH (4.0-8.0), total carbon (5.1-73.2 g kg(-1)), and textural classes (from sand to silty clay loam). Soils had various contents of metals (14-4500 mg kg(-1) for Zn, 18-6530 mg kg(-1) for Pb, and 0.17-34 mg kg(-1) for Cd), ranging from natural background levels to high contents indicative of industrial contamination in the region. Soil samples were scanned at the wavelengths from 400 to 2498 nm (near-infrared region) and from 2500 to 25000 nm (mid-infrared region). Calibrations were developed using the one-out validation procedure under partial least squares (PLS) regression. Mid-infrared spectroscopy markedly outperformed NIRS. Iron, Cd, Cu, Ni, and Zn were successfully predicted using DRIFTS. The coefficients of determination (R(2)) between actual and predicted contents were 0.97, 0.94, 0.80, 0.99, and 0.96 for those metals, respectively. Only Pb content was predicted poorly. Calibrations using NIRS were less accurate. Root mean squared deviation (RMSD) values were from 1.27 (Pb) to 3.3 (Ni) times higher for NIRS than for DRIFTS. Results indicate that DRIFTS may be useful for accurate predictions of metals if samples originate from one region. 相似文献