The Attractiveness of Five Common Mediterranean Weeds to Pollinators

Concerns about a global decline in pollinators have called for more knowledge about the factors influencing wild pollinator abundance and diversity in agroecosystems. Agricultural intensification has been identified as the main cause of this “global pollinator crisis”, particularly due to reductions in natural areas holding critical floral and nesting resources. Maintaining native wild plants in agricultural landscapes (e.g., in field margins) is often recommended as a cost-effective and efficient method for pollinator conservation. In this study, the role of common wild flowers, often considered weeds, in supporting pollinators in a Mediterranean agroecosystem was investigated. This work involved a two-year field trial to compare five native weed species common in Mediterranean cereal agroecosystems: Convolvulus arvensis L., Daucus carota L., Malva sylvestris L., Papaver rhoeas L., and Sonchus oleraceus L. The goal was to compare the attractiveness of these species, and a mixture of all five, to different flower-visiting insect groups in order to assess their value in supporting wild pollinators. Overall, D. carota had the highest number of insect visits, followed by P. rhoeas. C. arvensis, M. sylvestris, and S. oleraceus, which had lower numbers of visits. On the basis of their overall attractiveness to pollinators and low risk for invasiveness, D. carota, P. rhoeas, and M. sylvestris are the most likely to contribute positively to the conservation of pollinators in agroecosystems. Our results also suggest that it is advantageous for wild flowers sown for the purpose of pollinator conservation to be grown in clumps, rather than highly intermingled, for improved visitation rates.

The influence of recent Brazilian policy and legislation on increasing bee mortality

The decline in bee communities in recent years has been a major concern worldwide. The increase in the mortality of these pollinators is related to several factors, the main one being the intensive use of pesticides in agricultural crops. Brazil is the world leader in use of pesticides since 2008 and recent changes in legislation have facilitated the commercialization of certain pesticides whose marketing has been banned in several countries. This review addresses how current Brazilian legislation on agrochemicals has influenced the increase in bee mortality. Under the current federal government, in 2019 and 2020, 474 and 493 new pesticides were registered in the country, respectively, some of them classified as highly toxic to bees. In addition, public policies in Brazil led by certain sectors of agribusiness have also contributed to increase the number of threats and the mortality of bees, making it difficult for the beekeeping sector to act in opposition. Understanding how these policies directly affect pollinator conservation allows decision-making to help mitigate their environmental and economic impacts in Brazil. Otherwise, without effective actions to mitigate the abusive use of pesticides, the numerous studies demonstrating its direct impacts on the bee’s survival will be of no use.

Implications of Pollinator Biodiversity Decline for Food Security, Economy, and Pollinator Conservation Policies

Pollinator decline is one of the most significant ecological problems of the 21st century. This decline threatens human food security and global economy. In order to address this problem governments across Europe and the USA have introduced national pollinator conservation strategies. These strategies, however, significantly differ in approaches to conservation. The differences at least in part stem from lack of consensus in the literature on whether pollinator biodiversity or abundance of a few common species determines crop pollination. Critical evaluation of empirical evidence available to date outlined in this paper suggests that pollinator biodiversity rather than abundance of dominant species determine quality, magnitude and resilience of pollination ecosystem services to agriculture. In order to maintain pollinator biodiversity conservation strategies and initiatives should focus on enhancing habitat quality, complementarity and connectivity, rather than solely on increasing floral resource abundance and diversity within farmland fields. Conservation strategies currently underway need to be improved to address all three factors through landscape scale interventions. Countries that intend to design and introduce pollinator conservation strategies should take best practices from several existing strategies rather than choosing a single strategy as an example.