Epsilon Archive for Student Projects

Abstract

An overwhelming body of evidence shows that our modern intensive agricultural practices are no longer compatible with a sustainable future for humanity. Therefore, the question becomes: how
can we maintain the high yields necessary to feed our growing population in a manner which is sustainable? Here, agroecology and integrated pest and pollinator management (IPPM) offer a
potential solution. Agroecology is a scientific study, an agricultural practice and a social movement. In all its forms, agroecology aims to understand, utilize and promote biodiversity and ecosystem services in farmland to create a more socially, economically and environmentally sustainable food production system. IPPM is a decision-making framework which builds on two previous frameworks: integrated pest management (IPM), and integrated crop-pollination (ICP). Both of these previous frameworks suggest the utilization of multiple strategies in concert. IPM focuses on reducing pest pressure with the minimal usage of pesticides. Similarly, ICP aims to increase pollination ecosystem services with minimal use of managed bee hives. IPM has often been critiqued for (among other things) failing to recognize the substantial impact of pollinators in its research or methods. IPPM’s goal is to address this failure and to balance the benefits of pollination ecosystem services with the need for crop protection.
The composition of the agricultural landscape surrounding a farm is known to have impacts on both pollinator abundance, diversity and pollination services and on insect pest pressure. Metapopulation dynamics, insect dispersal distance, and the habitat composition of a landscape can all
affect populations of both insect pests and pollinators within a given field. In this study, we used faba bean (Vicia faba) as a model crop to examine how landscape factors
both within the same year and interannually affected pest pressure and pollination services. Fourteen
fields in Östergötland, Sweden, were selected to be studied. Two transects were constructed in each field, one 10 m from the field edge and the other 50 m from the field edge. Pollinators and flower surveys were conducted along each transect to determine the number of flower visitations by honeybees and bumblebees, along with the abundance of flowers. The same transects were then used to determine the number of eggs laid by the broad bean beetle (Bruchus rufimanus) and the subsequent proportion of beans that were damaged by the beetle. The surrounding landscape composition of each field was analyzed at 3 different spatial scales (1, 2 and 3 km from the focal field). The proportion of faba bean in the landscape in the previous year, the proportion of faba bean in the landscape in the current year, and the proportion of pasture in the landscape were all
determined. This data was then used to create 12 general linear mixed models (GLMM).
The models revealed that the number of faba bean fields in the landscape in the previous year increased the number of honeybee observations, but not bumblebees. Bumblebee observations were
significantly higher in the transect 50 m from the field edge when compared to the transect 10 m
from the field edge. The number of beetle eggs and the proportion of bean damage increased with the proportion of pasture in the landscape and the proportion of faba bean in the landscape in the current year. All of these effects changed with the spatial scale at which they were observed.
Our findings suggest that mass-flowering crops (MFCs) do not provide consistent enough floral
resources to increase the reproductive fitness of wild pollinator populations, but may benefit
managed honeybee populations. An increase in landscape heterogeneity, crop diversity and seminatural habitat (SNH) is suggested to provide a more steady supply of floral resources to wild pollinators. Our research also highlights both the importance and complexity of ecological
interactions and their effects on pest pressure and pollination at the landscape scale. In order to implement landscape-scale IPPM strategies along with many other agroecological methods that rely on biodiversity and ecosystem services, we will need further research to better understand these
complexities. However, further research will not be enough. Unprecedented cooperation and
communication among farmers, researchers, governing bodies and agricultural extension personnel
will be required. To achieve this level of communication and cooperation, radical change will have to occur in the social, political, economic and ecological systems that govern the composition of our agricultural landscapes.