Building effective policies to conserve pollinators: translating knowledge into policy

Models of bee responses to land use and land cover changes in agricultural landscapes - a review and research agenda

Predictive modelling tools can be used to support the design of agricultural landscapes to promote pollinator biodiversity and pollination services. Despite the proliferation of such modelling tools in recent decades, there remains a gap in synthesising their main characteristics and representation capacities. Here, we reviewed 42 studies that developed non-correlative models to explore the impact of land use and land cover changes on bee populations, and synthesised information about the modelled systems, modelling approaches, and key model characteristics like spatiotemporal extent and resolution. Various modelling approaches are employed to predict the biodiversity of bees and the pollination services they provide, with a prevalence of models focusing on wild populations compared to managed ones. Of these models, landscape indicators and distance decay models are relatively simple, with few parameters. They allow mapping bee visitation probabilities using basic land cover data and considering bee foraging ranges. Conversely, mechanistic or agent-based models delineate, with varying degrees of complexity, a multitude of processes that characterise, among others, the foraging behaviour and population dynamics of bees. The reviewed models collectively encompass 38 ecological, agronomic, and economic processes, producing various outputs including bee abundance, habitat visitation rate, and crop yield. To advance the development of predictive modelling tools aimed at fostering pollinator biodiversity and pollination services in agricultural landscapes, we highlight future avenues for increasing biophysical realism in models predicting the impact of land use and land cover changes on bees. Additionally, we address the challenges associated with balancing model complexity and practical usability.

Insect and arthropod conservation policies: the need for a paradigm shift

To date, insect conservation policy mainly consists of species protection lists, with some requiring habitat or ecosystem preservation to protect insect ecology. While a landscape or habitat approach seems the most appropriate for insect conservation, cases are rare of protected areas designated specifically for insects or other arthropods. Moreover, neither of these conservation approaches (species or habitat protection) have halted the worldwide decline in insects: species protection lists and reserves at best serve as band-aids for a massive hemorrhage. The main drivers of insect decline (global changes) are only loosely addressed by national and international policies. So, if we know the causes, what stands in the way of prevention and treatment for the problem? To save insects, our civilization needs psychotherapy rather than first-aid gestures: a paradigm shift that would place value on insects, and give rise to ecocentric policies informed by a wide range of stakeholders.

Investigation of Cowpea (Vigna unguiculata (L.) Walp.)–Insect Pollinator Interactions Aiming to Increase Cowpea Yield and Define New Breeding Tools

Impact of pollination on the agri-food sector is of paramount importance. Pollinators contribute to the maintenance of ecosystems, the reproduction and survival of many plants, and their presence usually leads to increased yield and quality of agricultural products. Breeding and selecting for plant traits for enhancing pollinator visits could therefore lead to more resilient farming systems. In stating the advantages of enhancing pollinators in agricultural systems, this study was designed aiming to assess six cowpea accessions for their flower traits and their effect on insect-pollinators. Pollinators species abundance and foraging activity was recorded and their impact on yield was investigated. Twenty-five of the twenty-seven flower traits studied differed statistically significantly among cowpea accessions. The main pollinators recorded belonged to the genus Xylocopa (Latreille, 1802). Seed and fresh pod yield was not affected by pollinators. The floral traits related to pollinators abundance and foraging activity were flower color, inflorescence position and the hours that the flowers per plant remained open during the day. However, they were not related linearly to pollinators abundance and foraging activity; therefore, they did not constitute safe traits for selection aiming to increase pollinators visitation. The findings suggested that other traits, such as pollen and nectar reward, probably perform a more important role in attracting pollinators compared to flower traits.

Surrogate species in pesticide risk assessments: Toxicological data of three stingless bees species

Discussions about environmental risk reassessment of pesticides have grown in the last decades, especially in tropical and subtropical regions since the diversity of bee species in these places is quite different. Stingless bees are highly affected by pesticides, and toxicity information is necessary to include them in the regulatory process of countries that hosts a diversity of these species. Therefore, the present study aimed to evaluate the Median Lethal Concentration (LC₅₀), estimate the Median Lethal Dose (LD₅₀) and compared the sensitivity of three species of stingless bees exposed to the commercial formulation of the neonicotinoid thiamethoxam (TMX). The LD₅₀ was estimated based on the LC₅₀ determined in the present study (LC₅₀ = 0.329 ng a.i./μL for Tetragonisca angustula; 0.624 ng a.i./μL for Scaptotrigona postica, and 0.215 ng a.i./μL for Melipona scutellaris). Considering these data, toxicity endpoints were used to fit species sensitive distribution curves (SSD) and determine the sensitivity ratio. The results showed that all the stingless bees tested are more sensitive to TMX than the Apis mellifera, the model organism used in ecotoxicological tests. Regarding the oral LC₅₀, the most susceptible and most tolerant species were M. scutellaris > T. angustula > S. postica > A. mellifera. Following the same evaluated pattern, for the LD₅₀ (considering the weight of the bees - ng a.i./g bee), we have: M. scutellaris > S. postica > T. angustula > A. mellifera, and without the weight considered (ng a.i./bee): T. angustula > M. scutellaris > S. postica > A. mellifera. The different sensitivities among stingless bee species highlight the importance of inserting more than one surrogate species with a variety of sizes in research and protocol development. Additionally, the research suggests the need to investigate patterns regarding the influence of body mass on pesticide sensitivity among stingless bee species.

Agriculture and Pollinating Insects, No Longer a Choice but a Need: EU Agriculture’s Dependence on Pollinators in the 2007–2019 Period

One of the new objectives laid out by the European Union’s Common Agriculture Policy is increasing environmental sustainability. In this paper we compare the degree of average dependence index for each member state (ADIMS) in EU28 from 2007 to 2019 in order to verify the following: (1) whether there was a difference in this index when comparing two CAP periods—(a) from 2007 to 2013 and (b) from 2014 to 2019—and (2) which crops had a larger effect on the ADIMS. The study showed no significant variation in the average ADIMS at EU level between the first (2007–2013) and second (2014–2019) CAP periods. The AIDMS index highlighted three types of EU agriculture: (1) agriculture in Eastern Europe, including Bulgaria, Hungary, Romania and Slovakia, characterized by a high level of ADIMS (10.7–22) due to the widespread cultivation of oil crops as rapeseed and sunflower; (2) Mediterranean agriculture including Portugal, Spain, Italy, Croatia, Greece, Malta, Cyprus and France with lower AIDMS levels (5.3–10.3) given their heterogeneous crop portfolios with different degrees of dependence on animal pollination (almond, soy, rapeseed, sunflower and tomatoes) and (3) continental agriculture including Germany, Austria, Slovenia, Poland, the Czech Republic, Baltic countries, Benelux, Finland, Sweden and Ireland, which are characterized by the lowest ADIMS level (0.7–10.6) due to the widespread cultivation of cereals (anemophily and self-pollination) which increase the denominator of the index. The study suggests that a sustainable management of the agroecosystem will be possible in the future only if CAP considers pollinators’ requirements by quantifying the timing and spatial food availability from cultivated and uncultivated areas.

Agroecological Strategies to Safeguard Insect Pollinators in Biodiversity Hotspots: Chile as a Case Study

Industrial agriculture (IA) has been recognized among the main drivers of biodiversity loss, climate change, and native pollinator decline. Here we summarize the known negative effects of IA on pollinator biodiversity and illustrate these problems by considering the case of Chile, a “world biodiversity hotspot” (WBH) where food exports account for a considerable share of the economy in this country. Most of Chile’s WBH area is currently being replaced by IA at a fast pace, threatening local biodiversity. We present an agroecological strategy for sustainable food production and pollinator conservation in food-producing WBHs. In this we recognize native pollinators as internal inputs that cannot be replaced by IA technological packages and support the development of agroecological and biodiversity restorative practices to protect biodiversity. We suggest four fundamental pillars for food production change based on: (1) sharing the land, restoring and protecting; (2) ecological intensification; (3) localized knowledge, research, and technological development; and (4) territorial planning and implementation of socio-agroecological policies. This approach does not need modification of native pollination services that sustain the world with food and basic subsistence goods, but a paradigm change where the interdependency of nature and human wellbeing must be recognized for ensuring the world’s food security and sovereignty.