Identify Management Options Research Articles

Effects of Patch Size and Type of Coffee Matrix on Ithomiine Butterfly Diversity and Dispersal in Cloud‐Forest Fragments

Determining the permeability of different types of landscape matrices to animal movement is essential for conserving populations in fragmented landscapes. We evaluated the effects of habitat patch size and matrix type on diversity, isolation, and dispersal of ithomiine butterflies in forest fragments surrounded by coffee agroecosystems in the Colombian Andes. Because ithomiines prefer a shaded understory, we expected the highest diversity and abundance in large fragments surrounded by shade coffee and the lowest in small fragments surrounded by sun coffee. We also thought shade coffee would favor butterfly dispersal and immigration into forest patches. We marked 9675 butterflies of 39 species in 12 forest patches over a year. Microclimate conditions were more similar to the forest interior in the shade-coffee matrix than in the sun-coffee matrix, but patch size and matrix type did not affect species richness and abundance in forest fragments. Furthermore, age structure and temporal recruitment patterns of the butterfly community were similar in all fragments, independent of patch size or matrix type. There were no differences in the numbers of butterflies flying in the matrices at two distances from the forest patch, but their behavior differed. Flight in the sun-coffee matrix was rapid and directional, whereas butterflies in shade-coffee matrix flew slowly. Seven out of 130 recaptured butterflies immigrated into patches in the shade-coffee matrix, and one immigrated into a patch surrounded by sun coffee. Although the shade-coffee matrix facilitated movement in the landscape, sun-coffee matrix was not impermeable to butterflies. Ithomiines exhibited behavioral plasticity in habitat use and high mobility. These traits favor their persistence in heterogeneous landscapes, opening opportunities for their conservation. Understanding the dynamics and resource requirements of different organisms in rural landscapes is critical for identifying management options that address both animals' and farmers' needs.

Weeds – friend or foe? The role of weed composition on stover nutrient recycling efficiency

In the upland soils of Northeast Thailand, most farmers can grow only one crop per year and soils are left fallow until the next crop, leading to the establishment of a native weed population. Additionally, these areas are often very sandy thus posing a high risk of nitrogen leaching during late or erratic and early rains occurring during the fallow period. Hence the objective of this study was to assess the impact of weeds and weed composition, i.e. native weed mixture, grass or legume/broadleaf dominated weed fallows over the dry season on nutrient recycling of groundnut ( Arachis hypogaea L.) stover, i.e. mineral N and microbial biomass N dynamics, 15N pre-crop residue recovery and subsequent effects on maize yield. Maize establishment was slowest ( P < 0.05) where grass and mixed weed grew during the fallow phase and maize dry weight was initially highest ( P < 0.05) in plots where no weeds were allowed to grow during the dry season. The negative effect of grass dominated weeds was due to microbial immobilization of soil mineral N in the presence of the low quality (higher C:N ratio and ADF fibre content) grass weeds. In the second maize crop there were some indications of release of immobilized microbial N. Negative effects of grass dominated weed fallows could be overcome by addition of split doses of N fertilizer. In contrast legume/broadleaf dominated weed populations led to less microbial immobilization of mineral N and resulted in faster net release of mineral N ( P < 0.05). As a consequence, maize yields in the legume/broadleaf weed treatment (5428 kg ha −1) were higher than in the grass (2899 kg ha −1), mixed weed (3120 kg ha −1) or no weed (3552 kg ha −1) fallows over two cropping cycles. 15N balance results indicated that mixed weeds retained more groundnut residue N in the soil organic pool than the treatment without weeds during the fallow phase although the effect was not significant at P < 0.05. Identifying management options that result in a dominance of broadleaf weed composition will be crucial if weeds growing during the dry season fallow period are to improve short-term nutrient recycling. Recycling grass dominated weed biomass will require judicious fertilizer amendments or incorporation well before maize planting to avoid competition for mineral N by the soil microbial biomass.

Plant parasite control and soil fauna diversity

The use of pesticides to control plant parasites and diseases has generated serious problems of public health and environmental quality, leading to the promotion of alternative Integrated Pest Management strategies that tend to rely more on natural processes and the active participation of farmers as observers and experimenters in their own fields. We present three case studies that point at different options provided by locally available populations of soil organisms, the maintenance of diverse populations of pests or increased resistance of plants to pest attacks by their interactions with earthworms and other useful soil organisms. These examples demonstrate the diversity of options offered by the non-planned agro-ecosystem diversity in pest control and the need to identify management options that maintain this biodiversity. To cite this article: P. Lavelle et al., C. R. Biologies 327 (2004).

A methodology for inferring the causes of observed impairments in aquatic ecosystems

Biological surveys have become a common technique for determining whether aquatic communities have been injured. However, their results are not useful for identifying management options until the causes of apparent injuries have been identified. Techniques for determining causation have been largely informal and ad hoc. This paper presents a logical system for causal inference. It begins by analyzing the available information to generate causal evidence; available information may include spatial or temporal associations of potential cause and effect, field or laboratory experimental results, and diagnostic evidence from the affected organisms. It then uses a series of three alternative methods to infer the cause: Elimination of causes, diagnostic protocols, and analysis of the strength of evidence. If the cause cannot be identified with sufficient confidence, the reality of the effects is examined, and if the effects are determined to be real, more information is obtained to reiterate the process.

Evidence Linking Delayed Mortality of Snake River Salmon to Their Earlier Hydrosystem Experience

The numbers of Snake River salmon and steelhead Oncorhynchus spp. have substantially declined since the completion of the Columbia River hydrosystem. We used analytical approaches to identify management options for halting the decline of these stocks, such as removal of Snake River dams and improvements to the existing hydrosystem. The benefits these actions are predicted to have in terms of salmon recovery hinge on whether the mortality that takes place in the estuary and early in their ocean residence is related to earlier hydrosystem experience during downstream migration. Evidence from the literature demonstrates numerous mechanisms that would explain this delayed mortality in relation to a fish's experience passing through the hydrosystem. Spatial and temporal comparisons of stock performance provide indirect evidence of delayed mortality and evidence that delayed mortality is linked to hydrosystem experience. Recent mark–recapture data also provide evidence of differences in delayed mortality by route of passage through the hydrosystem. The different types of evidence discussed here suggest that the delayed mortality of Snake River fish is related to the hydrosystem.

Factors Affecting Predation at Songbird Nests in Old Fields

We determined the effects of microhabitat, year, weather, time of season, stage of the nesting cycle, and brood parasitism on nest predation from a 7-year dataset on field sparrows (Spizella pusilla) and indigo buntings (Passerina cyanea) in central Missouri, USA. Year, site, and the interaction of species and 2-week interval of the season were important factors explaining nest predation. The only microhabitat variable that consistently explained predation was nest height: nests over 3 m high almost always fledged. Validation of the model parameters on an independent set of nests resulted in proper categorization (e.g., lost or not lost to predation) of 61.5% of nests. In models testing weather and temporal effects, year was related to daily survival for indigo buntings, and 2-week intervals of the season explained daily survival for both species. Nest predation was higher overall in the nestling stage than in the incubation stage for indigo buntings, and indigo buntings parasitized by brown-headed cowbirds (Molothrus ater) experienced higher predation than nonparasitized buntings. Temporal patterns within the breeding season were consistent between years, and between-year variance appeared to be important, whereas microhabitat was generally unimportant. Research on the mechanisms underlying temporal variability in nest mortality due to predation may identify management options to reduce nest predation.

A METHODOLOGY FOR INFERRING THE CAUSES OF OBSERVED IMPAIRMENTS IN AQUATIC ECOSYSTEMS

Biological surveys have become a common technique for determining whether aquatic communities have been injured. However, their results are not useful for identifying management options until the causes of apparent injuries have been identified. Techniques for determining causation have been largely informal and ad hoc. This paper presents a logical system for causal inference. It begins by analyzing the available information to generate causal evidence; available information may include spatial or temporal associations of potential cause and effect, field or laboratory experimental results, and diagnostic evidence from the affected organisms. It then uses a series of three alternative methods to infer the cause: Elimination of causes, diagnostic protocols, and analysis of the strength of evidence. If the cause cannot be identified with sufficient confidence, the reality of the effects is examined, and if the effects are determined to be real, more information is obtained to reiterate the process.

Sternal instability following coronary artery bypass grafting

Several cases of sternal instability have been noted in patients following coronary artery bypass graft surgery attending our cardiac rehabilitation programme. The purpose of this prospective study was to identify factors associated with sternal instability following sternotomy involving saphenous vein grafts (SVG) and unilateral or bilateral internal mammary artery (IMA) grafts. A rating scale for quantifying sternal instability was developed and used by the physiotherapists to assess all patients. Inter-therapist and intra-therapist reliabilities for the scale were calculated and these were 0.97 and 0.98 (ICC) respectively. Twenty-four patients who underwent coronary artery bypass grafting with a sternotomy incision presented with the complication of sternal instability 6-8 weeks following surgery. They represented 16.3% of the 147 patients presenting for cardiac rehabilitation who had undergone surgery interstate over an 18-month period. Sternal symptoms reported were pain, crepitus, and/or clicking at rest or on trunk and upper limb motion. Risk factors to wound healing such as obesity, diabetes, bilateral IMA grafting, osteoporosis, repeat operations, and prolonged post-operative mechanical ventilation were noted. A significantly higher proportion of patients with bilateral IMA grafting (31.5%) as opposed to unilateral IMA grafting (14.3%) had sternal instability (P <. 05). Quantifying the degree of sternal instability may play a role in identifying management options, patient progression and the point of intervention.

Users' guides to the medical literature: XVI. How to use a treatment recommendation. Evidence-Based Medicine Working Group and the Cochrane Applicability Methods Working Group.

Clinicians can often find treatment recommendations in traditional narrative reviews and the discussion sections of original articles and meta-analyses. Making a treatment recommendation involves framing a question, identifying management options and outcomes, collecting and summarizing evidence, and applying value judgments or preferences to arrive at an optimal course of action. Each step in this process can be conducted systematically (thus protecting against bias) or unsystematically (leaving the process open to bias). Clinicians faced with a plethora of recommendations may wish to attend to those that are less likely to be biased. Therefore, we propose a hierarchy of rigor of recommendations to guide clinicians when judging the usefulness of particular recommendations. Recommendations with the highest rigor consider all relevant options and outcomes, include a comprehensive collection of the methodologically highest quality data with an explicit strategy for summarizing the data (that is, a systematic review), and make an explicit statement of the values or preferences involved in moving from evidence to action. High rigor recommendations come from systematically developed, evidence-based practice guidelines or rigorously conducted decision analyses. Systematic reviews, which typically do not consider all relevant options and outcomes or make the preferences underlying recommendations explicit, offer intermediate rigor recommendations. Traditional approaches in which the collection and assessment of evidence remains unsystematic, all relevant options and outcomes may not be considered, and values remain implicit, provide recommendations of weak rigor. In an era in which clinicians are barraged by recommendations as to how to manage their patients, this hierarchy provides a potentially useful set of guides.

Modelling the distribution of red squirrels (Sciurus vulgaris) on the Isle of Wight

AbstractWe investigated the distribution of red squirrel (Sciurus vulgaris) populations on the Isle of Wight using Generalized Linear Models (GLMs) and a spatially explicit population dynamics model (SEPM) with the aim of identifying management options for red squirrel conservation. The presence/absence of red squirrels in habitat blocks in the landscape was used as the dependent variable and the size and separation of habitat blocks as independent variables in the GLM analysis. Red squirrel presence within a woodland was significantly related to woodland size and the distance to the nearest wood known to contain squirrels. The SEPM‐generated predictions on population viability were closest to the field data when a low dispersal distance of 1 km was used. This suggests that squirrel dispersal on the Isle of Wight is restricted. Our results suggest that some large interconnected woodlands should be maintained if red squirrels are to be conserved for the future.

Environmental Factors Influencing Summer Angler Effort on the Jordan Dam Tailwater, Alabama

Abstract The Coosa River below Jordan Dam, Alabama, supports a multispecies, warmwater, tailwater fishery. A principal concern has focused on maintaining sufficient flow to protect this fishery while simultaneously allowing substantial portions of water to be diverted from Jordan Lake through a new hydroelectric facility, from which the water is returned via a canal to the Coosa River 21 km below Jordan Dam, thus bypassing the Jordan Dam tailwater. To identify management options for the tailwater fishery during early and late summer fishing seasons, multipleregression models were generated with streamflow and climatic variables. In downstream reaches of the tailwater, water temperature and streamflow were the most important independent variables during early and late summer, respectively. The two most important variables identified for the stilling basin during these two seasons were secchi disc visibility and barometric pressure. In all reaches, angler effort was positively correlated with wind velocity ...

Total-Forest Concept in Multi-Resource Management

Abstract Management for multiple resources requires consideration of the entire forest rather than individual stands. In a fully regulated forest, changes in rotation age can compensate for stocking changes that affect product output. Hence, analysis of the interaction between rotation and stocking forestwide is necessary to identify management options for efficient production of conflicting benefits. An illustration is provided by an analysis of the production of grass and slash pine (Pinus elliottii Engelm.) in the southeastern Coastal Plain.