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Environmentally friendly landscape management improves oilseed rape yields by increasing pollinators and reducing pests

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Journal of Applied Ecology
Authors:
Thomas Perrot at FRB
Thomas Perrot
  • FRB
Vincent Bretagnolle at French National Centre for Scientific Research
Vincent Bretagnolle
Sabrina Gaba at French National Institute for Agriculture, Food, and Environment (INRAE)
Sabrina Gaba
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Abstract and Figures

Pollination and pest control are two major ecological functions sustaining crop yield. In insect‐pollinated crops, previous studies have revealed that an increase in resources and habitats in landscapes can increase pest control by natural enemies as well as insect pollination by pollinators. However, data have been lacking that simultaneously considers the effects of landscape on both pollinators and pests, and the direct and indirect effects on yields of farming practices interacting with landscape, bees and pests. This study aimed to fill this gap by focusing on oilseed rape (OSR), an insect‐pollinated crop of high economic value. We first quantified the effects of landscape and farming practices on both bee and pest abundance caught in OSR blooming season in 124 farmed fields over a 6‐year study (~20 fields sampled per year), and then used structural equation modelling to assess the direct and indirect links between bees, pests, farming practices and landscape on yield. The results showed that landscape had a stronger effect on bee and pest abundance than agrochemical farming practices. Bees and pests decreased with the amount of OSR in the landscape surrounding the focal field, and showed contrasted effects with the amount of meadow and organic farming: positive for bees and negative for pests. Bee abundance also increased with the amount of sunflower in the landscape the preceding year, and decreased with increasing field size. While agrochemicals surprisingly had barely any effect on bees and pests, their use improved OSR yield, although at a similar magnitude as bee and pest abundances. Synthesis and application. This study, conducted in commercial crop fields, underlines the important contribution of sustainable landscape management for enhancing OSR yield. Despite agrochemicals' ability to improve or maintain OSR yields, their unconditional use is unsustainable due to negative externalities. Therefore, alternative options such as those highlighted in our study—such as reducing field size, increasing the amount of organic farming in the landscape, or sowing OSR in landscapes rich in sunflowers the preceding year—appear to be relevant tools to promote ecosystem services, maintain yield and conserve biodiversity. These findings support the potential of nature‐based solutions to foster more sustainable agriculture.
Schematic representation of our research strategy to assess the direct and indirect effects of landscapes, farming practices, bees and pests on OSR yields. We first investigated the effect of landscape on bee and pest abundance (a), and then included the effect of farming practices and their interaction with landscape (b). Then we explored the direct effects of bee and pest abundance as well as farming practices on OSR yield (c). Linear models were used for these three steps. Finally (d), using structural equation modelling, we clarify the pathways through which landscape and farming practices affected OSR yields, that is, whether the effect was direct, indirect or both direct and indirect through bee and pest abundances. %OSR, %PastSun and %OF for respectively %oilseed rape, %past sunflower and % organically farmed fields.
Schematic representation of our research strategy to assess the direct and indirect effects of landscapes, farming practices, bees and pests on OSR yields. We first investigated the effect of landscape on bee and pest abundance (a), and then included the effect of farming practices and their interaction with landscape (b). Then we explored the direct effects of bee and pest abundance as well as farming practices on OSR yield (c). Linear models were used for these three steps. Finally (d), using structural equation modelling, we clarify the pathways through which landscape and farming practices affected OSR yields, that is, whether the effect was direct, indirect or both direct and indirect through bee and pest abundances. %OSR, %PastSun and %OF for respectively %oilseed rape, %past sunflower and % organically farmed fields.
… 
Effect of the proportion of (a) past sunflowers, (b) oilseed rape, (c) meadows, (d) organically farmed fields and (e) woods in the surrounding landscape on (a–e) bee and (f–j) pest abundance (estimated by pitfall traps). Solid lines show significant effects and dotted lines non‐significant effects as predicted by linear models. Shaded areas show confidence intervals at 95%. Buffer size estimated for each metric using the Siland method is indicated in brackets on the x‐axis. Bee and pest abundance is log‐transformed (see Section 2).
Effect of the proportion of (a) past sunflowers, (b) oilseed rape, (c) meadows, (d) organically farmed fields and (e) woods in the surrounding landscape on (a–e) bee and (f–j) pest abundance (estimated by pitfall traps). Solid lines show significant effects and dotted lines non‐significant effects as predicted by linear models. Shaded areas show confidence intervals at 95%. Buffer size estimated for each metric using the Siland method is indicated in brackets on the x‐axis. Bee and pest abundance is log‐transformed (see Section 2).
… 
Effects of (a) fertilizer intensity, (b) pesticide intensity, (c) bee and (d) pest abundance (estimated by pitfall traps) on OSR yields. Lines show significant effects as predicted by linear models. Solid lines represent significant relationships. Shaded areas show confidence intervals at 95%.
Effects of (a) fertilizer intensity, (b) pesticide intensity, (c) bee and (d) pest abundance (estimated by pitfall traps) on OSR yields. Lines show significant effects as predicted by linear models. Solid lines represent significant relationships. Shaded areas show confidence intervals at 95%.
… 
(a) Structural equation modelling (SEM) depicting the direct and indirect effects of farming practices and landscape on OSR yield through their effects on bee and pest abundances. Arrows are solid and black when the relationship is significant and dotted and grey when non‐significant. The marginal and conditional R² (denoted as R²m and R²c respectively) for yield, bee and pest abundances are provided. (b) Direct and indirect effects of farming practices, field size, landscape, bee or pest abundance on yield. Estimates and their confidence intervals were obtained by bootstrapping. Direct effects are black, and indirect effects are grey. Stars show significant effects. %OSR, PastSun and %OF for respectively %oilseed rape, %past sunflower and % organically farmed fields.
(a) Structural equation modelling (SEM) depicting the direct and indirect effects of farming practices and landscape on OSR yield through their effects on bee and pest abundances. Arrows are solid and black when the relationship is significant and dotted and grey when non‐significant. The marginal and conditional R² (denoted as R²m and R²c respectively) for yield, bee and pest abundances are provided. (b) Direct and indirect effects of farming practices, field size, landscape, bee or pest abundance on yield. Estimates and their confidence intervals were obtained by bootstrapping. Direct effects are black, and indirect effects are grey. Stars show significant effects. %OSR, PastSun and %OF for respectively %oilseed rape, %past sunflower and % organically farmed fields.
… 
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J Appl Ecol. 2022;59:1825–1836.  
|
 1825wileyonlinelibrary.com/journal/jpe
Received: 24 August 2021 
|
  Accepted: 1 April 2022
DOI: 10.1111/1365-2664.14190
RESEARCH ARTICLE
Environmentally friendly landscape management improves
oilseed rape yields by increasing pollinators and reducing pests
Thomas Perrot1,2  | Vincent Bretagnolle1,3  | Sabrina Gaba1,4
1Centre d'Etudes Biologiques de Chizé,
UMR7372, CNRS & Université de La
Rochelle, Villiers- en- Bois, France
2INRAE, UMR 1065 Sante et Agroécologie
du Vignoble, ISVV, Université de
Bordeaux, Villenave d'Ornon Cedex,
France
3LTSER « Zone Atelier Plaine & Val de
Sèvre », Villiers- en- Bois, France
4USC 1339 Agripop, Centre d'Etudes
Biologiques de Chizé, INR AE, Villiers- en-
Bois, France
Correspondence
Thomas Perrot
Email: tomperrt@gmail.com
Funding information
Agence Nationale de la Recherche, Grant/
Award Number: ANR- 18- CE32- 0002;
European Union's Horizon 2020, Grant/
Award Number: 862480; French Ministry
of the Environment, Grant/Award
Number: ‘Pollinisateurs’ project; regional
government of Nouvelle- Aquitaine, Grant/
Award Number: HARMONIE projec t
Handling Editor: Tim Diekötter
Abstract
1. Pollination and pest control are two major ecological functions sustaining crop
yield. In insect- pollinated crops, previous studies have revealed that an increase
in resources and habitats in landscapes can increase pest control by natural ene-
mies as well as insect pollination by pollinators. However, data have been lacking
that simultaneously considers the effects of landscape on both pollinators and
pests, and the direct and indirect effects on yields of farming practices interact-
ing with landscape, bees and pests.
2. This study aimed to fill this gap by focusing on oilseed rape (OSR), an insect-
pollinated crop of high economic value. We first quantified the effects of land-
scape and farming practices on both bee and pest abundance caught in OSR
blooming season in 124 farmed fields over a 6- year study (~20 fields sampled
per year), and then used structural equation modelling to assess the direct and
indirect links between bees, pests, farming practices and landscape on yield.
3. The results showed that landscape had a stronger effect on bee and pest abun-
dance than agrochemical farming practices. Bees and pests decreased with the
amount of OSR in the landscape surrounding the focal field, and showed con-
trasted effects with the amount of meadow and organic farming: positive for
bees and negative for pests. Bee abundance also increased with the amount of
sunflower in the landscape the preceding year, and decreased with increasing
field size.
4. While agrochemicals surprisingly had barely any effect on bees and pests,
their use improved OSR yield, although at a similar magnitude as bee and pest
abundances.
5. Synthesis and application. This study, conducted in commercial crop fields, un-
derlines the important contribution of sustainable landscape management for
enhancing OSR yield. Despite agrochemicals' ability to improve or maintain OSR
yields, their unconditional use is unsustainable due to negative externalities.
Therefore, alternative options such as those highlighted in our study— such as
reducing field size, increasing the amount of organic farming in the landscape,
or sowing OSR in landscapes rich in sunflowers the preceding year— appear to
© 2022 The Authors. Journal of Applied Ecology © 2022 British Ecological Society.
... This crop is highly sensitive to pests (Zheng et al., 2020). The cabbage stem flea beetles (Genus: Psylliodes) that are the focus here were the main pests identified in the study area (Perrot et al., 2022). ...
... The empirical models are parametrized using the following databases: (i) a farmers' survey database containing information on yield and farming practices (e.g., fertilizers measured in kg.ha −1 ; or pesticides measured by calculating treatment frequency indexes; see Möhring et al., 2019 for more details) and their associated costs in 294 oilseed rape fields surveyed in the study area from 2011 to 2018 (Catarino et al., 2019); (ii) a biodiversity database where bee and pest abundance were sampled in 124 fields from 2013 to 2018 (Perrot et al., 2022); (iii) a geographic information system for which soil characteristics and complete land use occupation (since 1994) have been recorded (Bretagnolle et al., 2018a); and (iv) a risk preferences database where the farmers' risk aversion coefficient distribution was evaluated in the study area using lottery experiments on 138 farmers (Couture and Gaba, 2021). ...
... Given the observed positive impact of SNHs on bee abundance in the study area (e.g., Perrot et al., 2022), this effect was retained in the baseline model. A hierarchical multilevel model with a sub-model of bee abundance was constructed that includes the SNH proportion in the landscape, the estimate of which was then integrated into the production model at the field scale; additional information is provided in Supplementary Material 2. SNHs thus have the double role 4 of reducing the risk by killing pests through natural enemies while increasing yields by increasing bees. ...
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... In the same study site, previous studies had shown a positive effect of bee abundance (i.e. honeybee and wild bees mainly Lassioglossum sp) on oilseed rape yield (Catarino et al., 2019;Perrot et al., 2018Perrot et al., , 2022. Only winter OSR is cultivated in the LTSER, representing usually 8 %− 10 % of the agricultural surface. ...
... phosphorus (54.7 kg/ha, 0-156.6) and potassium (29.9 kg/ha, 0-270) centered and scaled before summing up (see Perrot et al. 2022). OSR fields were sown with two main varieties DK Exstorm (17 fields) and DK Expertise (17 fields) both representing 23.6 % of the fields and the remaining fields (52.7 %) were sown with 18 different varieties (2.11±0.17 ...
... According to the latter, each supplementary% unity in oil content increases oilseed rape sell price by 1.5 %. In a previous study in our site, we found that absence of bee pollination resulted in OSR yield of only 2.55 t/ha, while in the presence of abundant bees, yield reached up to 0.84 t/ha (Perrot et al., 2022). With a sell price of 373.7 €.t − 1 (reference price Euronext May 2015) and for an average field size of 6.7 ha, the total gain for farmers would be 6384.7 € per field (Perrot et al., 2022). ...
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Global demand for vegetable oil is projected to expand to 28 Mt by 2028. Oilseed rape (OSR) is the predominant oilseed crop in Europe. Its nutritional value is determined by seed oil content and fatty acids (FAs) composition. Insect pollination increases seed oil content, however, its benefit on FAs composition remains unknown. In this study, we address this gap by investigating the variation of OSR seed oil content and FAs composition along a gradient of bee abundance in farmed OSR fields. We used a pollinator exclusion experiment to disentangle the contribution of pollination processes, i.e. wind, self and insect pollination. We show that bees improved OSR nutritional value by increasing amount of poly-unsaturated FAs and decreasing the amount saturated and trans-saturated FAs. In addition, oil content was higher in seeds with than without access to pollinators. Our study provides for the first time, to the best of our knowledge, evidence that insect pollination enhances the quality value of OSR oil by affecting FAs composition. Such effect implies potential negative consequences with any further decline of pollinator abundance. More investigations are also needed to better understand the mechanisms by which insect pollination affects FAs composition, and the way to enhance such mechanisms.
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... Оценка влияния ландшафта и методов ведения сельского хозяйства в течение 6-летнего исследования, а затем использование моделирования структурных уравнений для оценки прямых и косвенных связей между пчелами, вредителями и методами ведения сельского хозяйства позволили авторам утверждать, что увеличение разнообразия кормовых ресурсов и мест обитания в агроландшафтах может способствовать борьбе с вредителями со стороны естественных врагов, а также обеспечивать эффективное пчёлоопыление. Характеристики ландшафта, отличающегося видовым разнообразием энтомофильных растений, оказывают более сильное влияние на численность пчел и вредителей, чем агрохимические методы ведения сельского хозяйства [12]. Аналогичный результат был получен в исследованиях пестицидов при их использовании для защиты подсолнечника от вредителей и их влияния на опылителей и урожайность культуры [13]. ...
... Во многих публикациях указывается на необходимость обеспечения гармоничного сочетания интересов производителей растениеводческой продукции и пчеловодов на основе законодательного регулирования организационных, агрономических и пчеловодных мероприятий по предупреждению отравления пчелиных семей пестицидами с учётом негативного воздействия инсектицидных обработок на полезную энтомофауну [10][11][12][13]. ...
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It is generally recognised that pesticides play a significant role in the decline in the number of insects observed worldwide. The analysis of the causes of unprecedented losses of Apis mellifera L. bee colonies has been carried out. When using plant protection products in agrocenoses. The current state of knowledge on assessing the impact of pesticides on non–target objects is summarised as honey bees and other types of bee pollinators of plants. The mechanisms and features of selective exposure of insecticides from the group of neonicotinoids, butenolides and based on fipronil are described. In addition to direct lethal effects, there is a decrease in the viability and subsequent death of bee colonies as a result of changes in the cognitive abilities of worker bees, the reproductive potential of queens and drones, changes in the immune status of bee colonies and the etiological characteristics of insects. Examples of the negative impact on honeybee populations of various regions of the Russian Federation when using pesticides in agrocenoses are given. The role of organic agriculture in the conservation of honey bees and other pollinators, providing a yield comparable to the integrated plant protection system of entomophilic crops, is noted. Measures to prevent the reduction of honey bee populations due to pesticide toxicosis are outlined: 1. Compliance with the requirements of regulatory documents; 2. Providing apiaries with an optimal feed base; 3. Exclusion of highly toxic insecticides from entomophilic crop protection programs; 4. Realisation of the adaptive potential of honey bees in changing environmental conditions; 5. Transition to organic farming in the cultivation of entomophilic crops.
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... In other words, they explore methods to help food security without compromising biodiversity. For example, several studies developed how to increase genetic diversity by crossing crops with their wild relatives (e.g., Satori et al., 2021;Subbarao et al., 2021), and other studies developed land management methods such as organic amendments, crop rotation, and the creation of pollinator-friendly landscapes to further increase natural pollination by insects and reduce pests (e.g., Karuri, 2022;Perrot et al., 2022). Such methods can eventually reduce chemical inputs to agriculture and help maintain production while conserving biodiversity (e.g., Catarino et al., 2019;Valkó et al., 2022). ...
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As one of the efforts to combat climate change and the biodiversity crisis, an interest in nature-based solutions (NbS) has been growing. Although there have been diverse discussions on NbS, it is still insufficient to find a quantitative evaluation of the global research trends in which field and to what extent NbS has been studied. In this regard, this study employed latent Dirichlet allocation (LDA) topic modeling and keyword analysis to quantitatively evaluate the research trends of NbS. Among research papers on NbS searched on SCOPUS, 2,625 studies (2009-2022) were analyzed by LDA. As a result, NbS-related articles were classified into seven topics (i.e., Urban governance, Urban green infrastructure, Wastewater treatment, Coastal protection, Flood mitigation, Carbon sequestration, and Sustainable agriculture). Of these, the urban and water-related topics accounted for the largest proportion. In contrast, the carbon sequestration and sustainable agriculture topics accounted for a smaller proportion, but the proportion significantly increased over time. As a result of keyword analysis, the frequency of urban and water keywords remained high. In contrast, the frequency of climate change and carbon keywords was low and has recently increased. In the keyword network, the co-occurrence frequency and connection of urban and water keywords were initially high. Still, over time, keywords related to climate change and carbon increased similarly to those related to urban and water. The findings of this study imply that NbS has mainly focused on urban and water-related researches. Still, climate change and carbon-related researches may also be actively handled in relation to NbS in the near future.
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... . 2019). For example, farmers in the sample rank lack of resources as the third most 474 significant cause of decline, whereas it is actually the primary cause in the study area 475(Perrot, Bretagnolle, and Gaba 2022). Another example is the benefits to yield(Perrot et 476 al. 2018; 2019) and farmers' economic performance (Catarino et al. 2019; Faure, 477 Mouysset, and Gaba 2023) which were both quantified in the study area, point of discussion is the validity of these determinants more than ten 481 years after the survey. ...
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There is limited knowledge on why farmers adopt pollinator-supporting practices, which is crucial to stimulate their adoption. The dependence of farmers on pollination may influence their perception of pollinators and their willingness to adopt these practices. We addressed why farmers adopt pollinator-supporting practices using a 2011 survey conducted within a cereal plain in western France, where farmers were moderately dependent on pollination for crops like oilseed rape and sunflower. We assessed the factors influencing the adoption of practices to promote pollination, including pollination dependence. We found no effect for pollination dependence. Conversely, we found that farm size, pesticide use, advisory services and the perception of costs decreased the willingness to adopt, while older farmers were more incline to adopt. We also evaluated perceptions related to pollinators: more than 85% of farmers considered bees important for crop production and recognized pesticides as a major cause of decline. We found no effect of pollination dependence on farmers’ perceptions. Compared to similar studies over the past decade, we found similarities, particularly regarding pollinator-related perceptions. Finally, we compared the willingness to adopt in 2011 with the actual adoption in 2024, showing that there has been little change. This raises questions on the pathways to promote the adoption of pollinator-supporting practices to ensure for the future of pollinator conservation.
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... Soil micro-, meso-, and macrofauna are drivers of soil fertility and soil formation [24], while bees, syrphid flies, moths, and butterflies ensure the essential pollination of crops and wild plants [25]. They also provide benefits to farmers by improvements in soil health, insect pollination, and pest control through natural enemies [26]. Notably, species such as ladybirds and parasitoid wasps are effective biological controls against pests [27,28]. ...
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Insect pollination and biological pest control simultaneously influence crop yield, but are often investigated individually. This can lead to under‐ or over‐estimation of the importance of individual services when they interact to affect yield. Recent, limited evidence from field studies showed contrasting results with both additive and non‐additive positive and negative effects. To disentangle the mechanisms underlying these responses, we conducted a greenhouse experiment and a field study. We tested the potential and realized contribution of insect pollination to cotton boll retention and yield under various pest pressures and biocontrol levels. We found both additive and interactive effects of insect pollination and biocontrol within a single crop system depending on the level of pest pressure. In the greenhouse experiment, pollination did not contribute to cotton boll retention and final yield at low pest pressure. At high pest abundances, boll retention and final yield were higher when pollinators were present. In the field study, pollination was sufficient to alter the negative effect of pests on boll retention. Thus, interactive effect between the two ecosystem services on boll retention was present at high pest pressure in the greenhouse and at natural levels of pest pressure in the field, but not at lower pest abundances in controlled conditions. Although cotton plants partly compensated for bolls shedding by increasing their weight in the greenhouse experiment, this effect was not detected in the field study, likely due to higher environmental variation. Similarly, interactive effect of pollination and biocontrol on the final yield was present only in the greenhouse study. Synthesis and applications. We conclude that the contrasting findings of additive versus non‐additive effects between ecosystem services may be due to the levels of services and disservices tested and environmental variation. Further, this study shows that even when an ecosystem service does not appear to limit crop yield, it can make a substantial contribution to yield and act as insurance when the other service is reduced. For achieving food and fibre security, it is essential that future studies test interactive effects between these ecosystem services in different systems and environmental conditions.
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Global agricultural productivity is threatened by increasing pollinator dependence without a parallel increase in crop diversification
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Full-text available
  • Jul 2019
The global increase in the proportion of land cultivated with pollinator‐dependent crops implies increased reliance on pollination services. Yet agricultural practices themselves can profoundly affect pollinator supply and pollination. Extensive monocultures are associated with a limited pollinator supply and reduced pollination, whereas agricultural diversification can enhance both. Therefore, areas where agricultural diversity has increased, or at least been maintained, may better sustain high and more stable productivity of pollinator‐dependent crops. Given that >80% of all crops depend, to varying extents, on insect pollination, a global increase in agricultural pollinator dependence over recent decades might have led to a concomitant increase in agricultural diversification. We evaluated whether an increase in the area of pollinator‐dependent crops has indeed been associated with an increase in agricultural diversity, measured here as crop diversity, at the global, regional, and country scales for the period 1961–2016. Globally, results show a relatively weak and decelerating rise in agricultural diversity over time that was largely decoupled from the strong and continually increasing trend in agricultural dependency on pollinators. At regional and country levels, there was no consistent relationship between temporal changes in pollinator dependence and crop diversification. Instead, our results show heterogeneous responses in which increasing pollinator dependence for some countries and regions has been associated with either an increase or a decrease in agricultural diversity. Particularly worrisome is a rapid expansion of pollinator‐dependent oilseed crops in several countries of the Americas and Asia that has resulted in a decrease in agricultural diversity. In these regions, reliance on pollinators is increasing, yet agricultural practices that undermine pollination services are expanding. Our analysis has thereby identified world regions of particular concern where environmentally damaging practices associated with large‐scale, industrial agriculture threaten key ecosystem services that underlie productivity, in addition to other benefits provided by biodiversity. Increasing cultivation of pollinator‐dependent crops has placed a stress on global pollination capacity, which could have been ameliorated by a concomitant increase in agricultural diversification. However, this study reports a relatively weak and decelerating rise in agricultural diversity over time that was largely decoupled from the strong and continually increasing trend in agricultural dependency on pollinators. Particularly worrisome is a rapid expansion of pollinator‐dependent monocultures in several countries of the Americas and Asia that has resulted in a decrease in agricultural diversity. In these regions, reliance on pollinators is increasing, yet agricultural practices that undermine pollination services are expanding.
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Biocontrol in insecticide sprayed crops does not benefit from semi‐natural habitats and recovers slowly after spraying
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To enhance biological pest control in crop fields, it is recommended to increase semi‐natural area on farm and decrease insecticide spraying. While the benefits of semi‐natural area for biocontrol in unsprayed fields are often demonstrated, it remains largely unknown if there are any benefits in real‐world, commonly sprayed crops. Here, we explored the combined effects of semi‐natural field margins and insecticide spraying on pest (cotton bollworm) egg predation in 53 Australian cotton fields and semi‐natural field margins across 2 years. We used predation experiments close to field edges to exclude functional groups of predators depending on their spatio‐temporal activity (diurnal vs. nocturnal and ground vs. canopy dwelling) and digital cameras to record natural enemy taxa responsible for predation. Ground predation was substantially higher than canopy predation and its magnitude in unsprayed crops with semi‐natural margins was similar to that within semi‐natural areas. In contrast, semi‐natural field margins did not benefit biocontrol in sprayed crop fields and did not influence recovery rate of biocontrol after spraying. Within ground‐dwelling predators, one dominant taxon contributed the most to biocontrol at a particular time and place. However, the dominant predator–prey interactions changed between day and night and fields with and without margins, thus indicating increased importance of additional predator taxa with increasing spatio‐temporal scales. Synthesis and applications. Our results show that semi‐natural margins benefit pest control only in unsprayed fields. Spraying at different time (e.g. during night) would not reduce the negative effects of insecticides because it would affect complementary group of nocturnal natural enemies that exert equally high biocontrol as diurnal ground‐dwelling predators. We highlight the need for management recommendations to simultaneously consider pros and cons of within‐field spraying and surrounding semi‐natural habitats to maximize their benefits in high‐input conventional production systems.
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Delivering Integrated Pest and Pollinator Management (IPPM)
Article
  • Mar 2020
  • TRENDS PLANT SCI
The need to reduce pollinator exposure to harmful pesticides has led to calls to expedite the adoption of integrated pest management (IPM). We make the case that IPM is not explicitly ‘pollinator friendly’, but rather must be adapted to reduce impacts on pollinators and to facilitate synergies between crop pollination and pest control practices and ecosystem services. To reconcile these diverse needs, we introduce a systematic framework for ‘integrated pest and pollinator management’ (IPPM). We also highlight novel tools to unify monitoring and economic decision-making processes for IPPM and outline key policy actions and knowledge gaps. We propose that IPPM is needed to promote more coordinated, ecosystem-based strategies for sustainable food production, against the backdrop of increasing pesticide regulation and pollinator dependency in agriculture. Video Abstract Download : Download video (26MB)
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Revisiting advice on the analysis of count data
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O'Hara and Kotze ( Methods Ecol Evol 1: 118–122, 2010) present simulation results that appear to show very poor behaviour (as judged by bias and overall accuracy) of linear models applied to count data, especially in relation to GLM analysis. We considered O'Hara and Kotze's (2010) comparisons, and determined that the finding occurred primarily because the quantity that they estimated in their simulations of the linear model analysis (the mean of a transformation of the count data) was not the same quantity that was simulated and to which the results were compared (the logarithm of the mean of the count data). We correct this discrepancy, re‐run O'Hara and Kotze's simulations and add additional simple analyses. We found that the apparent superiority of the GLMs over linear models in O'Hara and Kotze's (2010) simulations was primarily an artefact of divergence in the meanings of results from the two analyses. After converting results from linear model analyses of transformed data to estimators of the same quantity as provided by the GLM, results from both analyses rarely differed substantially. Furthermore, under the circumstances considered by O'Hara and Kotze, we find that an even simpler implementation of linear model analysis, inference of the mean of the raw data, performs even better and gives identical results to the GLM. While the analysis of count data with GLMs can certainly provide many benefits, we strongly caution against interpreting O'Hara and Kotze's (2010) results as evidence that simpler approaches are severely flawed.
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