Realistic Management Scenarios Research Articles

Wheel track loosening can reduce the risk of pesticide leaching to surface waters

AbstractWheel tracks can lower topsoil infiltrability and increase water ponding in agricultural fields. A seedbed harrow mounted with two goosefeet tine points, the eradicators, was used to investigate track loosening at different depths on a sandy loam soil as a way of mitigating compaction effects and reducing the risk of pesticide transport to surface waters. Loosening strongly affected air permeability and steady‐state infiltration. The agro‐ecological system model Daisy was used to simulate the effects of soil structural and hydraulic changes on pesticide leaching to subsurface drain lines over a 332‐year period. Measured properties of the topsoil were combined with a representative subsoil and weather series and with realistic management scenarios. The loads of pesticide in the drains for 3 months after loosening were calculated for each year, and the risk was defined as the 90th percentile of the load. We focused on three different herbicides used in sugar beet cultivation in spring: glyphosate, metamitron and phenmedipham. Our simulations showed that for all pesticides loosening could lower the risk by 10% on average for a 3‐m working width, and the tracks contribution to the risk by 34%, for all drain spacing and working width settings. Wheeling did not affect the risk but this result was sensitive to the parameterization of the hydraulic conductivity in the compacted soil layer, showing potentially higher risk under certain conditions. These results showed that wheel track loosening is an effective strategy for reducing the risk of surface water contamination from pesticides used in agriculture.

Impact of fire and harvest on forest ecosystem services in a species‐rich area in the southern Appalachians

AbstractTo mitigate and adapt to climate change, forest carbon sequestration and diversity of the ecosystem must be included in forest management planning, while satisfying the demand for wood products. The future provisions of ecosystem services under six realistic management scenarios were assessed to achieve that goal. These services were carbon sequestration, types and quantities of roundwood harvested, and different indicators of forest health—biomass of major species, species diversity, and variation of tree age. A spatially explicit forest succession model was combined with statistical analyses to conduct the assessment at the level of both the whole forest landscape and different ecological zones (ecozones) within. An important aspect of this study was to explore the effects of the biophysical heterogeneity of different ecological zones on the outcomes of different management scenarios. The study area was located in an area of the southern Appalachian Mountains in North Carolina with high tree diversity and active forest management activities. Along with a range of management practices, such richness in diversity allowed us to examine the complexity of the interaction between management activities and species competition. The results showed that fire suppression had a greater effect on increasing biomass carbon sequestration than any management scenario that involves harvest and replanting afterward, but at the expense of other indicators of forest health. The effect of fire on species composition was the largest in the xeric parts of the study area. Based on the study results, it was proposed that a low harvest intensity with a mix of fire and fire suppression across the landscape would best balance the need for roundwood products, biomass carbon sequestration, and desirable species composition. This study also demonstrated that the combination of a spatially explicit forest succession model and statistical analyses could be used to provide a robust and quantifiable projection of ecosystem service provisions and possible trade‐offs under different management scenarios.

Conservation practitioners' understanding of how to manage evolutionary processes.

Both academics and practitioners consider a lack of knowledge about evolutionary theory to be a general barrier to effectively managing genetic diversity. However, it is challenging to judge practitioners' level of understanding and how this influences their management decisions. Knowledge built through experience may be difficult for practitioners to articulate, but could nonetheless result in appropriate management strategies. To date, researchers have assessed only the explicit (formal) knowledge practitioners have of evolutionary concepts. To explore practitioners' understanding of evolutionary concepts, it is necessary to consider how they might apply explicit and implicit knowledge to their management decisions. Using an online survey, we asked Australian practitioners to respond to 2 common management scenarios in which there is strong evidence that managing genetic diversity can improve outcomes: managing small, isolated populations and sourcing seeds for restoration projects. In describing their approach to these scenarios, practitioners demonstrated a stronger understanding of the effective management of genetic diversity than the definitions of the relevant concepts. However, their management of genetic diversity within small populations was closer to best practice than for restoration projects. Moreover, the risks practitioners described in implementing best practice management were more likely to affect their approach to restoration than translocation projects. These findings provide evidence that strategies to build the capacity of practitioners to manage genetic diversity should focus on realistic management scenarios. Given that practitioners recognize the importance of adapting their practices and the strong evidence for the benefits of actively managing genetic diversity, there is hope that better engagement by evolutionary biologists with practitioners could facilitate significant shifts toward evolutionarily enlightened management.

Anthropic and natural factors drive variation of survival in the red‐legged partridge in southern France

Understanding demographical processes underlying abundance and population size fluctuations is critical to species management. Knowing key parameters and responses to observed changes can reduce the number of realistic management scenarios. In hunted species, survival might be the targeted parameter for effective plans. The red‐legged partridge Alectoris rufa is a native species in Mediterranean countries. The species is hunted, especially in France where some release plans are implemented. However, survival estimates are scarce there and most studies were conducted in Spain. Here, we took advantage of a radio‐tracking experiment in southern France (200 birds surveyed) to estimate monthly and annual survival rates of both wild and released red‐legged partridge and to investigate the temporal, spatial and individual variations in survival. We found very high annual survival rate in our island site (0.70) and low survival elsewhere (range: 0.25–0.29). We showed that age and sex were a significant source of variation in annual survival of wild birds with lower estimates for young and for females. The close survival between mainland sites with different mortality sources suggests that compensation may occur between predation and hunting mortality. However, a stronger assessment of this point is needed. Our study suggests that environment characteristics, especially landscape mosaic and predation pressure, was a driver of survival. On the island site, the red‐legged partridge shows a different demographic tactics (higher survival, lower reproduction) than in mainland, suggesting an adaptation to the context (lower predation). Regarding hand‐reared birds released just before the hunting season, their survival to the next spring was lower than 0.05. Such a low value raises the issue of using release before the hunting season for reinforcement purpose, especially due to negative impact through the general increase in hunting pressure it promotes. Habitat and hunting management may thus be a key to favour the red‐legged partridge.

Arsenic Distribution and Speciation in a Managed Turfgrass System Following Monosodium Methylarsenate Application

ABSTRACTMonosodium methylarsenate (MSMA) is an organic arsenical herbicide commonly used in certain warm‐season turfgrasses. Recently, concerns about MSMA use have arisen because of the release of As into the environment, although the fate of applied As is not well quantified for realistic management scenarios. Greenhouse lysimeter experiments were conducted to determine As distribution and speciation over time following an MSMA application to established bermudagrass [Cynodon dactylon (L.) Pers.]. At 1 wk after treatment (WAT), up to 65% of As from MSMA was detected in bermudagrass clippings and the remaining aboveground vegetation. Elevated soil and porewater As concentrations were detected to 5 cm depth but increases were not observed below this depth. Mass balance calculations revealed that As partitioned into the soil over time, with 91% of the applied As residing in the upper 5 cm of soil solids by 8 WAT. Arsenate was the dominant As species by 2 WAT and thereafter in porewater and soil. Results indicate that turfgrass management plans could be altered to minimize potential off‐target contamination from MSMA by returning clippings following mowing events and using MSMA in a herbicide rotation.

Assessing the health of the U.S. west coast with a regional-scale application of the Ocean Health Index.

Management of marine ecosystems increasingly demands comprehensive and quantitative assessments of ocean health, but lacks a tool to do so. We applied the recently developed Ocean Health Index to assess ocean health in the relatively data-rich US west coast region. The overall region scored 71 out of 100, with sub-regions scoring from 65 (Washington) to 74 (Oregon). Highest scoring goals included tourism and recreation (99) and clean waters (87), while the lowest scoring goals were sense of place (48) and artisanal fishing opportunities (57). Surprisingly, even in this well-studied area data limitations precluded robust assessments of past trends in overall ocean health. Nonetheless, retrospective calculation of current status showed that many goals have declined, by up to 20%. In contrast, near-term future scores were on average 6% greater than current status across all goals and sub-regions. Application of hypothetical but realistic management scenarios illustrate how the Index can be used to predict and understand the tradeoffs among goals and consequences for overall ocean health. We illustrate and discuss how this index can be used to vet underlying assumptions and decisions with local stakeholders and decision-makers so that scores reflect regional knowledge, priorities and values. We also highlight the importance of ongoing and future monitoring that will provide robust data relevant to ocean health assessment.

Revisions of the Fish Invasiveness Screening Kit (FISK) for its Application in Warmer Climatic Zones, with Particular Reference to Peninsular Florida

The initial version (v1) of the Fish Invasiveness Scoring Kit (FISK) was adapted from the Weed Risk Assessment of Pheloung, Williams, and Halloy to assess the potential invasiveness of nonnative freshwater fishes in the United Kingdom. Published applications of FISK v1 have been primarily in temperate-zone countries (Belgium, Belarus, and Japan), so the specificity of this screening tool to that climatic zone was not noted until attempts were made to apply it in peninsular Florida. To remedy this shortcoming, the questions and guidance notes of FISK v1 were reviewed and revised to improve clarity and extend its applicability to broader climatic regions, resulting in changes to 36 of the 49 questions. In addition, upgrades were made to the software architecture of FISK to improve overall computational speed as well as graphical user interface flexibility and friendliness. We demonstrate the process of screening a fish species using FISK v2 in a realistic management scenario by assessing the Barcoo grunter Scortum barcoo (Terapontidae), a species whose management concerns are related to its potential use for aquaponics in Florida. The FISK v2 screening of Barcoo grunter placed the species into the lower range of medium risk (score = 5), suggesting it is a permissible species for use in Florida under current nonnative species regulations. Screening of the Barcoo grunter illustrates the usefulness of FISK v2 as a proactive tool serving to inform risk management decisions, but the low level of confidence associated with the assessment highlighted a dearth of critical information on this species.

A qualitative multi-attribute model for assessing the impact of cropping systems on soil quality

Summary An important goal of the European Commission-funded ECOGEN project is to develop a computer-based decision support system (DSS) for the assessment of economic and ecological impacts of using genetically modified crops. In ecological impact assessment, special emphasis is put on soil biology and estimating soil quality from the observed biological parameters. Methodologically, we have addressed this goal using model-based DSS, taking the approach of qualitative multi-attribute modelling. The approach is based on developing various hierarchical multi-attribute models that consist of qualitative attributes and utility (aggregation) functions, represented by decision rules. The model presented in this paper assesses the impact of cropping systems on soil quality and can subsequently be used to assess crop management options. It was developed as a collaboration between ECOGEN soil experts and decision analysts, and consists of 34 attributes, hierarchically structured into eight levels. There are 21 input attributes, most of which measure the richness and biomass of representative soil organisms. The assessment of soil quality is based on two main indicators: (1) soil diversity (assessed through microfauna, mesofauna and macrofauna richness) and (2) soil functioning (in terms of leaching, comminution, mineralisation and plant growth). In the paper, we address the methodological aspects of the model and its development, and describe the components of the model (attributes, value scales, decision rules and weights). We present initial results of its application to the assessment of crop management on soil quality in the case of using conventional and Bacillus thuringiensis (Bt)-maize at three field sites in France and Denmark. Our finding was that soil quality was unaffected even though several input attributes had changed. We also analyse the sensitivity of the model and discuss its current and potential contribution to soil quality management. The model is operational (available through a web page) and can be used for the assessment, comparison and analysis of realistic management scenarios. Furthermore, it provides an effective means of synthesising a lot of data, encoding knowledge about soil-quality factors, supporting communication among experts, answering ‘what-if’ and ‘so-what’ questions, and supporting the evaluation of new agricultural practices.

Mobile software agents for decentralised network and systems management

Mobile Agent (MA) technology has been proposed for Network and Systems Management (N&SM) as an answer to the scalability limitations of centralised models and the flexibility problems of static hierarchical frameworks. Nevertheless, much is still to be done to deploy MA-based management frameworks that efficiently cope with the dynamically changing traffic and topological characteristics of modern networks. This paper starts with an extensive review of the research approaches on MA-based management. Then, we propose a highly adaptive and dynamic hierarchical MA-based framework for N&SM that is based on appropriate policies to enable automatic calibration of the management system depending on network conditions. The applicability of the introduced framework is tested in realistic management scenarios and three applications on network monitoring are proposed.