Mean Field Size Research Articles

Landscape crop diversity contributes to higher pollination effectiveness and positively affects rapeseed quality in Mediterranean agricultural landscapes

Pollination is crucial for biodiversity and food security. Heterogeneous agricultural landscapes have a positive effect on pollinator abundance and enhance crop production and quality. In this study, we explored the effects of three landscape features (past crop diversity measured as the Equivalent Richness of crop functional Groups in the previous year [ERGp], semi-natural habitat percentage [SNH], and mean field size [MFS]) and pollinator densities (wild bees [WB] and honey bees [HB]) on pollination and seed quantity and quality in rapeseed crops. Surveying the pollinator density in 20 rapeseed fields revealed a positive relationship with ERGp in the landscape. A pollinator exclusion experiment compared bagged and open-pollinated self-compatible rapeseed plants and revealed insect pollination effectiveness (fruits per flower and number of seeds per pod) and seed quality (oil content). Seed parameters were evaluated in relation to pollinator density (WB-HB) and landscape characteristics. The ERGp emerged as a crucial landscape feature that positively impacted WB density. When insect pollinators were excluded, plants exhibited reduced pollination effectiveness and seed quality. Analysis of open-pollinated plants highlighted ERGp as the most influential variable, positively affecting both sets of parameters. The MFS and SNH showed different but important relationships. Total tocopherol and α-tocopherol were positively correlated with pollinator density in HB, whereas WB showed a positive correlation with γ-tocopherol levels. Increased ERGp positively affected pollinator density and pollination effectiveness, thereby improving oilseed rape production quantity and quality. This study provides new insights into agroecosystem management and pollinator-friendly practices.

Woody semi‐natural habitats modulate the effects of field size and functional crop diversity on farmland birds

Abstract Agricultural intensification has simplified landscape composition and configuration, which has led to biodiversity declines. Increasing landscape‐wide crop heterogeneity can promote farmland biodiversity. However, knowledge is still lacking on how the effects of configurational and compositional crop heterogeneity (i.e. field size and crop diversity) are modulated by the amount of semi‐natural habitats in the landscape, especially across large scales. We tested how mean field size and functional crop diversity affect farmland bird diversity and abundance over three consecutive years, and how these effects are modulated by the amount of small woody features (SWF) in the landscape. We related data from a national bird monitoring scheme to field‐level information from a novel, high‐resolution remote sensing‐based crop type map. Smaller field sizes and higher functional crop diversity were not generally associated with a higher diversity or abundance of farmland birds. Associations varied with species' breeding habitat preferences and were modulated by the amount of SWF. In landscapes with a low SWF amount, species diversity and the abundance of species breeding in field edges or shrubs were negatively associated with increasing field size. However, where the amount of SWF was high, larger field size was associated with higher species diversity and abundance of field and shrub breeders. Diversity increased with higher functional crop diversity, as did the abundance of non‐field breeders in landscapes with a medium to high SWF amount. Field size tended to have a stronger effect on bird diversity and abundance than functional crop diversity. Policy implications: National and EU agricultural policies should adopt a landscape perspective by considering the amount of semi‐natural habitats when designing biodiversity‐enhancing measures that target field size and functional crop diversity. In landscapes with low SWF amount, decreasing field sizes may be particularly effective to promote farmland bird diversity and the abundance of non‐field breeders. In landscapes with a medium to high SWF amount, increasing functional crop diversity is likely more effective than reducing field sizes. Field and shrub breeders may be promoted by maintaining landscapes with large fields, only if these offer a high SWF amount, low agronomic yield potential and low productivity.

Effects of agricultural landscape heterogeneity on pollinator visitation rates in Mediterranean oilseed rape

Agricultural intensification, by changing land use and modifying the yearly configuration and composition through crop sequences, affects the abundance and diversity of pollinators and, consequently, pollination. This study aims to assess the impact of the characteristics of agricultural landscapes on pollinator abundance in the Mediterranean region. We studied the response of three major wild pollinator groups (hoverflies, bumblebees, and wild bees) to four landscape characteristics: three related to composition, namely, equivalent crop diversity in the sampling year (eRg), previous year equivalent crop diversity (eRgP) and percentage of seminatural habitats (SNH), and one related to landscape configuration, namely, mean field size (MFS). For this evaluation, we selected twenty-two oilseed rape fields (OSRs) differing in surrounding landscape characteristics within a 1-km radius. Multimodel inference indicates that landscape variables affect pollinator groups differently. The percentage of SNH was the most important variable having a positive influence on the abundance of bumblebees, while eRgP and MFS were found to be important for the abundance of wild bees and hoverflies. These data allow us to prioritize actions aimed at specific groups of pollinators, improve agricultural landscape schemes, promote the conservation of wild pollinators, promote crop diversity at the landscape scale and increase the extent of seminatural areas.

What can we learn from the past? Tracking sustainability indicators for the Swedish dairy sector over 30 years

CONTEXTThe dairy sector has undergone profound transformation over recent decades, resulting in considerably fewer but larger and more specialised farms, with unclear implications across sustainability dimensions. OBJECTIVEThe objective was to develop and employ a framework for assessing sustainability in the Swedish dairy sector to shed light on how recent historical developments (1990–2020) have influenced sustainability outcomes. METHODSUsing a data-driven, multidisciplinary approach, main areas of concern for sustainability in the primary production stages of the dairy sector were identified. These were then populated with indicators to track developments over time and highlight synergies and trade-offs. RESULTS AND CONCLUSIONSFour areas of concern were identified and populated with eight indicators (listed in brackets): ‘supporting ecosystems’ (semi-natural grassland area, ley area, mean field size), ‘climate impact’ (methane from enteric fermentation), ‘animal welfare’ (veterinary treatments, percentage of culled cows due to diseases) and ‘farm viability’ (competitive wages, farmer age structure). The results showed that area of semi-natural grassland per dairy cow decreased by 27% from 2003 to 2020. Area of ley per cow decreased slightly but the proportion of arable land on dairy farms devoted to ley cultivation increased, due to improved roughage quality enabling an increase in proportion of roughage in feed rations. In terms of climate impact, enteric methane emissions per kg milk decreased by 21%. Regarding animal welfare, veterinary treatments of diseases decreased from 45% to 21% over the 30 years, with declining trends for most recorded diseases except hoof disease. The indicators for farm viability showed that the average dairy farm was unable to pay a wage comparable to the national average throughout most of the period 2004–2020, but a slightly positive trend was observed, although with large year-on-year variability. A rapid change in age structure was seen between 2003 and 2020, with the proportion of land managed by older farmers (+60 years) increasing from 12% to 22%, indicating challenges with demographic viability. SIGNIFICANCETracking changes over time across sustainability dimensions gives important insights into improvements made and challenges that remain to be solved. Overall, developments in the Swedish dairy sector have diminished its capacity to support ecosystems, particularly related to semi-natural grasslands, while reducing its climate impacts and improving animal welfare. An increased specialisation has also resulted in spillover effects where services and impacts have shifted from dairy herds to specialised beef herds. These findings are important in navigating policy processes targeting developments in the dairy sector.

Satellite-based multi-annual yield models for major food crops at the household field level for nutrition and health research: A case study from the Nouna HDSS, Burkina Faso

Increasing frequencies of climate change-induced extreme weather events like prolonged droughts pose significant challenges for small-scale subsistence farmers in sub-Saharan Africa, who rely on the yearly harvest by more than 80 % of their nutritional needs. However, we do not have a good understanding of yield estimates at the field and household level (with a mean field size of < 2 ha) to understand nutritional priorities in vulnerable communities due to their scarcity in the literature, particularly yield estimates that do not require re-collection of in-situ data. Statistical models for estimating regional food crop yields based on high-resolution satellite data at the field level may provide better insights into how to address health risks such as child malnutrition. Especially in low-resource contexts, where the burden is greatest and expected to worsen in future climate projections. Our study developed crop-specific, satellite-based yield models using a novel three-year data set of in-situ yield measurements as exemplified for a rural region in Burkina Faso. The aim of the model is to reduce the need for in-situ field data collection while still assuring accurate yield estimates at the field level. The model employed LASSO regression and was based on monthly vegetation index composites from Sentinel-2 and weekly accumulated Climate Hazards Group InfraRed Precipitation with Station (CHIRPS) rainfall data. Our yield modeling results showed that there was less overfitting when there was more training data over three years that demonstrated a wider range of yields, which also led to better model fits. R² values ranged from 0.62 (Maize) to 0.3 (Sorghum) for the three-year yield models, with normalized root mean square error (nRMSE) values ranging from 12 % − 16 %. An additional plausibility check confirmed the validity of our models, as we compared the magnitude of our yield estimation with national yield statistics for Burkina Faso. We demonstrated that our models based on three years of in-situ data may capture some of the inter-annual variability in yields, which could be a step toward minimizing the necessity for in-situ measurements in the future. Our advances in predicting yield estimates at the field level enable a linkage between household-level yields, socioeconomic indicators, nutritional status of children, and the health status of the household members. A further application is linking high-resolution yield data to farmers’ productivity losses from increasing heat under climate change.

Combination of organic farming and flower strips in agricultural landscapes – A feasible method to maximise functional diversity of plant traits related to pollination

Agri-environment schemes (AES) are valuable instruments to support pollination in agricultural landscapes. Evaluating AES based on their effects on pollinators has high practical relevance for agricultural production and nature conservation. In our two-year assessment, we studied the effectiveness of two AES (organic farming vs flower strips) on plant traits associated with pollinator attraction (flower size, colour, and ultraviolet pattern) and reward accessibility (flowering duration, and nectar quantity). We selected ten landscapes along a landscape-scale field size gradient in Central Germany. Three types of winter wheat fields (organic, and conventional fields with and without flower strips) were chosen in each landscape. We sampled the vegetation in transects designated in characteristic field parts, i.e. grassy margins, field edges (or flower strips), and field interiors in the growing seasons of 2016 and 2017. We calculated community-weighted means and functional diversity of plant traits and tested the effects of field size, management, and within-field position with linear mixed-effects models. We showed that organic fields and flower strips provided more abundant and functionally more diverse flowers than conventional fields. Flower strips were superior with the highest insect-pollinated plant cover and the highest ratio of plants with flowers showing ultraviolet patterns. Although grassy margins next to flower strips harboured twice as many species as those without flower strips, this positive effect did not emerge in conventional field interiors. Landscape configuration expressed as mean field size did not affect pollination traits in our study. Our results highlighted that both organic farming and flower strips maintained abundant and functionally diverse insect-pollinated flora, and thus they can potentially support larger pollinator communities. However, only organic farming could maintain high functional diversity of pollination-related plant traits in field interiors. Hence flower strips and organic farming in combination might be a good option for sustaining diverse pollinator communities and their services. • Organic fields and annual wildflower strips can boost pollinator-friendly flora. • Plant pollination trait diversity is high in both agro-environmental schemes. • Both schemes can supposedly maintain high pollination ecosystem service. • There is little spill-over from flower strips to intensive field interiors. • Plant functional diversity of grassy field margins benefited from flower strips.

Legacy of landscape crop diversity enhances carabid beetle species richness and promotes granivores

It is well understood that agricultural expansion and associated loss of semi-natural habitat in the landscape are major drivers for the marked decline in biodiversity. While conserving remaining semi-natural habitat patches is essential to reverse ongoing biodiversity declines, increasing focus has also been put on diversifying cropland itself by increasing landscape crop diversity as a measure of compositional heterogeneity, and reducing field sizes as a measure of configurational heterogeneity. Both these cropland diversification approaches have shown promise to enhance biodiversity in the year of sampling, but it is unknown whether legacies of crop diversity in the landscape promote biodiversity by building up arthropod communities over time. We selected 14 faba bean fields in landscapes dominated by cropland. The fields were chosen along three gradients: landscape crop diversity of the year of sampling (2017), landscape crop diversity of the previous year (2016) and mean field size in landscapes. Using pitfall traps, we show that the carabid beetle species richness is higher in landscapes with higher crop diversity in the previous year. Especially, granivorous carabid beetles benefitted from legacies of crop diversity. Rove beetles were more abundant and genus rich in landscapes with larger field sizes, while spiders were not responding to any of the landscape variables. A diversity of crops in the landscape and their associated weed communities could provide more diverse food resources and shelter habitats, which build populations of carabid beetle species over time. There is a need to explore the effects of agri-environmental schemes across multiple years to better understand legacy effects, and to structure sustainable agricultural landscapes.

Competition and Facilitation Effects of Semi-Natural Habitats Drive Total Insect and Pollinator Abundance in Flower Strips

Flower strips are an effective agri-environmental measure to promote functional biodiversity and ecosystem services in agricultural landscapes. In particular, tailored annual flower strips are increasingly implemented to foster insect pollination and biological pest control. While positive effects of flower strips on service providers and associated ecosystem services were recently demonstrated, little is known about how their effectiveness is affected by the surrounding landscape. We investigated how landscape composition and configuration, as well as flower strip traits influence the abundance of all insects, pollinators and natural enemies in 74 annual flower strips across 7 years (2014–2020). Landscape characteristics such as crop diversity, mean field size, area, and quality of semi-natural farmland habitats were assessed in a 1-km radius surrounding flower strips and combined with flower strip traits such as size, flower coverage, and flowering plant species richness to model insect abundance and diversity. Total insect and pollinator abundance, as well as wild bee abundance, richness, and diversity in flower strips were negatively affected by the share of semi-natural farmland habitats in the surrounding landscape, suggesting a dilution effect. On the other hand, semi-natural habitats with elevated ecological quality (i.e., biodiversity promotion areas with high botanical and structural diversity) enhanced total insect and pollinator abundance in flower strips. Furthermore, pollinator abundance and wild bee abundance in specific were positively affected by the flower coverage of the strips. Our results therefore suggest simultaneous competition and facilitation effects of semi-natural habitats on the landscape scale depending on their ecological quality. Annual flower strips will therefore be most effective in fostering services in landscapes of moderate to low complexity but with a high share of semi-natural habitats with increased ecological quality. For additional benefits for pollinator and wild bee abundance, flower strips should be designed to yield high flower cover. Our study thus highlights the importance of quality of ecological infrastructure and provides recommendations to maximize ecosystem services and biodiversity by means of flower strips at the landscape scale.

Automated Functional Color Field Tester (FCFTester) Trends and Reproducibility – A Multicenter Pilot Study

Background: The present study was designed to assess a protocol for investigating normative trends of kinetic color visual field sizes and reproducibility of such utilizing the Automated Functional Color Field Tester (FCFTester). Methods: The participants were recruited at three clinical sites. The participants were screened for the study based on a questionnaire designed by the authors to help assess the inclusion and exclusion criteria. There were 116 adult-only participants, however, only those reporting White race (n = 106) were used for statistical analysis. The mean age was 35.8 (std = 14) and nearly 70% of the sample was female. Results: This study demonstrated that kinetic visual field sizes across all four color isopters are not influenced by gender (p = 0.96) nor eye tested (p = 0.46). Only a slight difference in mean visual field sizes was found between the three clinical sites ranging from less than 2.5 degrees when the target was blue or green to less than 1.5 degrees for white or red targets. Overall, age had limited, yet significant, influence on kinetic field sizes likely related to the relatively young age of our participants. A significant difference in mean field size existed when comparing the four color isopters with an ascending order of green, red, blue, and white. This pattern was consistent across the three testing sites. Variability in field size for each color isopter was slight across the three clinical sites. Conclusion: The present pilot study shows promise that a protocol can be established to provide reproducible data and normative trends in kinetic color visual field testing. The authors recognize that this should be achievable with further refinement of the current testing protocol.

Farmland heterogeneity is associated with gains in some ecosystem services but also potential trade-offs

The intensification of farming practices negatively impacts the provision of many non-food ecosystem services (ES), including pollination, pest regulation and water quality regulation. Incorporating greater landscape heterogeneity in cropped areas, especially by increasing crop diversity and the density of field edges (i.e. greater farmland heterogeneity), may be a key lever to increase non-food ES provision in agricultural landscapes. However, most work to date focuses on the effects of farmland heterogeneity on biodiversity or on a single ES at a single spatial scale. Understanding how farmland heterogeneity affects multiple ES across spatial scales is critical to exploring whether increasing this heterogeneity is a feasible management solution to increase ES provision in agricultural landscapes. We measured the effects of farmland heterogeneity on the provision of eight key ES (crop production, soil fertility, water quality regulation, carbon storage, bee and syrphid pollination, and aphid and defoliator regulation) in the Montérégie, an important agricultural region in Quebec, Canada. We sampled 32 soybean fields embedded within landscapes that fell along independent gradients of mean field size and crop diversity. We evaluated the effects of heterogeneity on these eight ES at two spatial scales (500 m and 1000 m radii around fields), while controlling for the effects of in-field management practices. We found that the mean size of agricultural fields had a stronger influence on ES provision than crop diversity, especially at the 500 m scale. We observed varying responses to mean field size for different ES, which may lead to trade-offs for landscape management. Landscapes with smaller fields benefitted from greater bee pollination, water quality regulation and defoliator regulation, but had less crop production and aphid regulation. To further explore these trade-offs, we calculated the multiple ecosystem service landscape index to assess multifunctionality, but found no significant relationship between mean field size and multifunctionality and a negative relationship between crop diversity and multifunctionality. Our findings show that different ES respond differently to changes in heterogeneity, and efforts to manage heterogeneity to improve ES provision will need to acknowledge and understand possible trade-offs, particularly for crop production and pest regulation services.

Organic farming supports lower pest infestation, but fewer natural enemies than flower strips

Abstract Agricultural intensification has led to dramatic losses of species and associated ecosystem services. In the European Union, agri‐environment schemes (AESs) have been developed to mitigate these challenges. There are two opposing AES strategies, targeting either production or non‐production areas. Organic farming focuses on production and conservation on the same land‐use area, whereas flower strips adjacent to crop fields are in favour of intensified conventional production combined with conservation strips outside the cultivated area. We investigated pest and natural enemy abundances of organic farming versus establishing flower strip in 10 agricultural landscapes in Central Germany along a gradient of mean field size (1.24–6.78 ha). We focused on three winter wheat fields per landscape: conventional field (control), conventional field with adjacent flower strip and organic field. We sampled crop pests such as cereal leaf beetles (CLBs) and cereal aphids as well as their natural enemies. Our results indicated that the abundance of CLB larvae was more than two times higher in conventional farming with and without flower strip than that in the organic farming. The abundance of natural enemies was supported by landscapes with small mean field size, that is their numbers increased c. threefold when field size decreased from 7 to 2 ha. Aphid abundance was lower in organic fields and conventional control fields than in conventional fields with flower strips suggesting a potential disservice of flower strips. Parasitoids and natural enemies benefited from flower strips, but they were obviously not able to control the aphids. Synthesis and applications. The major pests in cereals, aphids and CLBs infested organic farming less than flower strips along conventional fields. However, the abundance of natural enemies of pests benefited from flower strips and, in addition, from decreasing field size in agricultural landscapes. Hence, enhancing predator populations for more effective biological pest control may be best with decreasing field sizes combined with organic farming and flower strips. Altogether, organic farming might contribute much more to low pest damage than a conventional farming strategy with flower strips.

More milkweed in farmlands containing small, annual crop fields and many hedgerows

Milkweed has declined substantially, with over 80% declines in some agricultural regions. This threatens monarch butterfly (Danaus plexippus) persistence, because monarch larvae feed solely on milkweed. Thus conservation actions are needed to enhance the availability of milkweed, particularly in agricultural landscapes. Conservation actions to date have largely focused on reducing intensive agricultural practices, mainly use of herbicides. However, research suggests that landscape-scale alteration of the cropped portion of an agricultural landscape (the "farmland"), for example, to reduce crop field sizes, can benefit herbaceous plants such as milkweed. Here we collected data on milkweed occurrence and cover in agricultural landscapes in Ontario, Canada, capturing variability in milkweed from field edge to interior by sampling in the interior and along the edges of 68 crop fields. We used these data to evaluate the relative effects of farming practices within the sampled field (e.g. herbicide, fertilizer use) on milkweed versus the effects of mean field size, crop diversity, hedgerow cover, and the proportion of farmland in annual crops in the surrounding landscape. Additionally, we evaluated the effects of these variables on the cover of other herbaceous plants, to identify which—if any—could benefit milkweed without increasing overall weed cover. We found more milkweed at sites surrounded by landscapes with smaller crop fields, lower crop diversity, and higher cover of annual crops. Milkweed was more likely to occur at sites surrounded by landscapes with more hedgerows. These landscape-scale effects on milkweed were often larger than those of within-field farming practices. Importantly, we found that most variables had opposite effects on milkweed relative to other plants. Thus, altering the landscape to benefit milkweed does not imply an increase in weed cover.

Cropland heterogeneity drives frequency and intensity of pesticide use

Agricultural landscapes across the planet have replaced natural habitat with crop production that is less diverse at field and landscape scales. Loss of cropland heterogeneity can increase pest colonization rates and decrease predation rates, thereby exacerbating pest pressure and leading to increased use of pesticides. Linking landscape pattern, crop pest pressure, and pesticide use is emerging as critical step for understanding the benefits, and potential trade-offs, of diversified agriculture. We advance this work by exploring how cropland heterogeneity drives pesticide use, and whether this effect is modified by pesticide class (i.e. fungicide, herbicide or insecticide). We focus on a diverse growing region, California’s Central Valley, and use spatial auto-regressive models to test for consistent class-based differences in the relationship between pesticide use and cropland heterogeneity (i.e. mean field size and landscape-level crop diversity). We find reduced pesticide use, in terms of both frequency and intensity of application, in diversified, spatially-heterogenous landscapes. Additionally, we see (a) more consistent responses of fungicides and insecticides to landscape pattern, (b) pesticide use increases as cropland becomes more homogenous with respect to crop identity, and (c) this effect is more consistent for perennial crops than annual crops. The modifying influence of pesticide class is largely consistent with expectations from ecological theory. Our results support increasing focus on whether enhancing the heterogeneity of the crop mosaic itself can benefit biodiversity, ecosystem services, and human well-being.

Arthropod functional traits shaped by landscape-scale field size, local agri-environment schemes and edge effects

Agri-environment scheme (AES) approaches can be classified according to whether they prescribe management in non-productive areas, such as field boundaries and wildflower strips, or in productive areas, such as arable crops. Here we tested the ecological effectiveness of two popular AESs in Germany: wildflower strips next to winter wheat fields as off-field management and organic farming on winter wheat fields as on-field management. We selected ten landscapes along a field size gradient with three focal wheat fields, one conventional field with flower strip, one organic field and one conventional field without flower strip as a control. We sampled arthropods with pitfall traps at field edges and field interiors. We selected three ecological traits for spiders and carabids (body size, feeding trait, dispersal ability). We calculated community weighted mean values (CWM), and we used linear mixed effects models to test the effect of management type and transect position on CWM values. We found pronounced edge effects on most traits, and weaker effects of field size and AES in shaping functional traits. Smaller spiders, spiders with higher ballooning propensity and more web-builders were in the field interior than at the field edge, whereas carnivore carabids preferred field interiors. We also found a strong effect of landscape configuration, i.e. mean field size, as larger field size was positively related to more web-building spiders and more carnivore beetles. Flower strips enhanced populations of web-building spiders. Our results suggest that small-scale agriculture leading to high landscape-scale edge density has a major effect in shaping functional traits and potential ecosystems services in agricultural landscapes. Spider and carabid communities exhibit very different responses to edge vs. interior sites, and, based on the landscape-scale field size gradient emphasize the importance of landscape configuration in shaping the heterogeneity of the arthropods’ traits and presumably ecosystem services in agricultural landscapes.

Agriculture intensification reduces plant taxonomic and functional diversity across European arable systems

Abstract Agricultural intensification is one of the main drivers of species loss worldwide, but there is still a lack of information about its effect on functional diversity of arable weed communities. Using a large‐scale pan European study including 786 fields within 261 farms from eight countries, we analysed differences in the taxonomic and functional diversity of arable weeds assemblages across different levels of agricultural intensification. We estimated weed species frequency in each field, and collected species' traits (vegetative height, SLA and seed mass) from the TRY plant trait database. With this information, we estimated taxonomic (species richness), functional composition (community weighted means) and functional diversity (functional richness, evenness, divergence and redundancy). We used indicators of agricultural management intensity at the individual field scale (e.g. yield, inputs of nitrogen fertilizer and herbicides, frequency of mechanical weed control practices) and at the landscape scale surrounding the field (i.e. number of crop types, mean field size and proportion of arable land cover within a radius of 500 m from the sampling points). The effects of agricultural intensification on species and functional richness at the field scale were stronger than those of intensification at the landscape scale, and we did not observe evidence of interacting effects between the two scales. Overall, assemblages in more intensified areas had fewer species, a higher prevalence of species with ruderal strategies (low stature, high leaf area, light seeds), and lower functional redundancy. Maintaining the diversity of Europe's arable weed communities requires some simple management interventions, for example, reducing the high intensity of field‐level agricultural management across Europe, which could be complemented by interventions that increase landscape complexity. A free Plain Language Summary can be found within the Supporting Information of this article.

Identifying factors that influence bird richness and abundance on farms

ABSTRACTCapsule: Farmers can influence species richness and abundance of typical farmland birds positively, even on rather small farms (20–50 ha) within intensively farmed areas.Aims: To assess the impact of farm settings, farm characteristics and heterogeneity of habitats on bird species richness and abundance, and to indicate which actions and measures farmers can take to promote farmland birds at a farm level.Methods: Farmland bird species richness and abundance were modelled as a function of farm settings, farm characteristics and semi-natural habitats on 133 farms. The data were analysed at the farm scale, as this is the ‘operating range’ of a farmer, but also at the territory scale, which represents the range birds (mainly passerines) use during the breeding season. Additionally, effects of the farm variables on species abundance/occurrence were investigated for nine widespread species.Results: Farmland bird species abundance (but not richness) was elevated on organic compared to non-organic farms. Farmland bird species richness and abundance increased with decreasing mean field size. Crop diversity had positive effects on five species at the territory scale. Several semi-natural habitats, especially hedgerows, were associated with higher bird species richness and abundance at both farm and territory scales. Settlement revealed rather negative effects at the farm scale, but several positive relations at the territory scale.Conclusion: Birds, especially passerines, are restricted to a small area during the breeding season, and so even small farms can contribute to their protection by growing diverse crops, reducing field size and managing a diversity of semi-natural, uncropped habitats. These measures should ideally be accessible within the relatively small scale of a bird territory.

Responses of anurans to composition and configuration of agricultural landscapes

It is imperative to identify farming systems that support biodiversity. Amphibians are the most threatened class of vertebrates globally and are particularly sensitive to the impacts of agricultural intensification. While it is known that areas of natural cover are important for amphibians in farmland, it is unknown whether cropped areas of the landscape can be structured in ways that benefit them. We examine relationships between anurans (frogs and toads) and farmland heterogeneity (structural complexity of cropped areas). We hypothesize that anurans benefit from higher compositional and configurational heterogeneity via increased prey resources and refuge habitat, and facilitation of movement. We measure compositional heterogeneity as crop diversity and configurational heterogeneity as mean field size in agricultural landscapes. We predicted that anuran richness and abundance are positively related to crop diversity and negatively related to mean field size. We surveyed 34 agricultural landscapes in eastern Ontario, Canada, representing gradients in farmland heterogeneity, for anuran richness and abundance. We used a multi-model inference approach to calculate and compare model-weighted mean coefficients to determine the direction and relative importance of landscape variables on anuran response variables. While species richness and abundance were most strongly related to the amount of forest in the landscapes, anuran abundance was also negatively related to mean field size (i.e. positive association with configurational heterogeneity). In addition, the presence of one species, the American toad, was positively associated with crop diversity. Our results suggest that conserving natural habitats such as forest is the most effective means of maintaining anuran diversity and abundance in agricultural landscapes, but that increasing the landscape configurational heterogeneity through reduction of crop field sizes can provide an additional strategy to enhance anuran abundance.

Receptive field size, chemical and thermal responses, and fiber conduction velocity of rat chorda tympani geniculate ganglion neurons.

Afferent chorda tympani (CT) fibers innervating taste and somatosensory receptors in fungiform papillae have neuron cell bodies in the geniculate ganglion (GG). The GG/CT fibers branch in the tongue to innervate taste buds in several fungiform papillae. To investigate receptive field characteristics of GG/CT neurons, we recorded extracellular responses from GG cells to application of chemical and thermal stimuli. Receptive field size was mapped by electrical stimulation of individual fungiform papillae. Response latency to electrical stimulation was used to determine fiber conduction velocity. Responses of GG neurons to lingual application of stimuli representing four taste qualities, and water at 4°C, were used to classify neuron response properties. Neurons classified as SALT, responding only to NaCl and NH4Cl, had a mean receptive field size of six papillae. Neurons classified as OTHER responded to salts and other chemical stimuli and had smaller mean receptive fields of four papillae. Neurons that responded to salts and cold stimuli, classified as SALT/THERMAL, and neurons responding to salts, other chemical stimuli and cold, classified as OTHER/THERMAL, had mean receptive field sizes of six and five papillae, respectively. Neurons responding only to cold stimuli, categorized as THERMAL, had receptive fields of one to two papillae located at the tongue tip. Based on conduction velocity most of the neurons were classified as C fibers. Neurons with large receptive fields had higher conduction velocities than neurons with small receptive fields. These results demonstrate that GG neurons can be distinguished by receptive field size, response properties and afferent fiber conduction velocity derived from convergent input of multiple taste organs.

Kerma-area product is not a useful indictor of potential tissue reactions in interventional radiology

Potential for tissue reactions post interventional radiological procedure is well recognised. Identifying tissue reactions is not always straight forward and implementation of international guidance varies.This single site study investigates the appropriateness of using a kerma-area product value of 500 Gy cm2 (assumed field size 100 cm2) to highlight potential skin injury/tissue reactions post interventional radiology procedures. MethodKerma-area product doses for all interventional radiological procedures over a 2 year period in a major tertiary referral hospital were retrospectively audited. A PKA of 500 Gy cm2 was used as an indicator of necessitating patient follow up for potential tissue reactions (potential peak skin dose of 3 Gy). Procedure parameters were recorded for all procedures reaching this dose. These were used to devise clinically representative phantom studies to facilitate peak skin dose measurement for each procedure identified. Results5156 interventional radiology procedures were reviewed. 13 patients registered a kerma-area product dose of 500 Gy cm2 or more. 6 patients underwent percutaneous cardiac interventions and 7 had embolization of gastro-intestinal haemorrhage.Subsequent phantom studies representative of percutaneous cardiac interventions and embolization of gastro-intestinal haemorrhage procedures resulted in peak skin doses of 2.6 Gy and 1.5 Gy respectively for a PKA value of 500 Gy cm2. ConclusionA Kerma-area product of 500 Gy cm2 alone is not a useful indicator of potential tissue reactions for percutaneous cardiac interventions or gastrointestinal haemorrhage embolization's. Extensive analysis of procedure parameters (particularly c arm movement, focus to skin distance and mean field size) post procedure is suggested to further quantify potential for tissue reaction.

An audit of over two decades of treating pituitary adenomas at a tertiary care facility

Aims: This retrospective audit of long-term outcomes and treatment sequelae with conventional radiotherapy (RT) is presented with an objective to provide baseline data with which outcomes of high precision techniques (fractionated radiosurgery and intensity-modulated RT [IMRT]) may be compared. Materials and Methods: Between the years 1990 and 2012, a total of 182 patients of pituitary adenoma were registered in the Department of Radiotherapy. Of these, 156 received RT. Immobilization consisted of a plaster of Paris cast (1990–1995), acrylic cast (1996–2000), a three-point head fixation thermoplastic cast (2001–2006), and now we are using “U”-IMRT thermoplastic cast since 2007 onward. A 2-field technique was used in 7% patients, whereas in the remaining 93% patients, 3-field technique was used. Forty-seven percent of patients were treated on a telecobalt unit and the remaining 53% patients on 6 MV linear accelerator. Rectangular fields, no field shaping, and appropriate wedges were used with mean field sizes (standard deviation [SD] and range) being 41.4 cm2 (16, 25–100). Mean dose (SD, range) was 47.5 Gy (SD 3.2; range 45–55) given in 1.8–2.0 Gy/fraction, 5 fractions/week. Results: Sixty percent of patients were (93/156) males. Median age was 37 years (mean - 37, SD - 13.2, range 12–66); 40.4% (63/156) had functional tumors. Presenting features were mainly headache 125 (80%), field defects 91 (58.3%), menstrual disturbances 33 (53% of women), and acromegalic features 38 (24.4%). Suprasellar extension, 129 (82.7%), was most common. All patients underwent resection; out of them, 28.2% patients had multiple surgeries. At a median (range) follow-up of 33 months (2–212) of all patients, the estimated freedom from progression was 96% at 2 years and 92% at 5 and 10 years with no patient failing beyond 18 months. Conclusions: Conventional external RT as described in postoperative cases of pituitary adenoma is safe and effective for tumor control with a median time to normalization of hormonal hypersecretion being about 30 months.