Agricultural intensification continues to diminish many ecosystem services in the North American Corn Belt. Conservation programs may be able to combat these losses more efficiently by developing initiatives that attempt to balance multiple ecological benefits. In this study, we examine how seed mix design and first year management influence three ecosystem services commonly provided by tallgrass prairie reconstructions (erosion control, weed resistance, and pollinator resources). We established research plots with three seed mixes, with and without first year mowing. The grass‐dominated “Economy” mix had 21 species and a 3:1 grass‐to‐forb seeding ratio. The forb‐dominated “Pollinator” mix had 38 species and a 1:3 grass‐to‐forb seeding ratio. The grass:forb balanced “Diversity” mix, which was designed to resemble regional prairie remnants, had 71 species and a 1:1 grass‐to‐forb ratio. To assess ecosystem services, we measured native stem density, cover, inflorescence production, and floral richness from 2015 to 2018. The Economy mix had high native cover and stem density, but produced few inflorescences and had low floral richness. The Pollinator mix had high inflorescence production and floral richness, but also had high bare ground and weed cover. The Diversity mix had high inflorescence production and floral richness (comparable to the Pollinator mix) and high native cover and stem density (comparable to the Economy mix). First year mowing accelerated native plant establishment and inflorescence production, enhancing the provisioning of ecosystem services during the early stages of a reconstruction. Our results indicate that prairie reconstructions with thoughtfully designed seed mixes can effectively address multiple conservation challenges.

The Earth’s entomofauna seems in an ongoing state of collapse. Insect decline could pose a global risk to key insect-mediated ecosystem functions and services such as soil and freshwater functions (nutrient cycling, soil formation, decomposition, and water purification), biological pest control, pollination services and food web support that all are critical to ecosystem functioning, human health and human survival. At present the attention for insect decline is low in all domains, ranging from scientific research to policy-making to nature conservation. Scientists made urgent calls to prioritise insect conservation. An international treaty for global pollinator stewardship and pollinator ecosystem restoration is urgently needed to counteract the current crisis. A review of insect pollinator conservation policies found that despite scientific calls and public outcry to develop polices that addresses declines, governments have not delivered such legislation, nor have they met basic monitoring needs recommended by experts.

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.[Display omitted]

Within global crop production 1961–2012, the share of pollinator independent crops increased twofold, but fourfold of pollinator dependent crops. Balanced diets within the boundaries of our planet require even more pollinator dependent crops. Particularly, Low and Middle Income Countries in the drylands produce pollinator dependent crops. However, climate change and agriculture increasingly cause risks for pollinators. Common reward-based seeding of wildflower strips is too expensive for these countries. Breeding towards pollinator independent crops might accelerate loss of pollinators. Recent publications warned that pollinator loss can reduce other ecosystem services supporting crop production. A new alternative approach called Farming with Alternative Pollinators (FAP) might fill the gap. FAP creates on-farm habitable conditions for pollinators and increases productivity and incomes per surface.

Urban areas are growing worldwide and alter landscapes in a persistent fashion, thereby affecting biodiversity and ecosystem services such as pollination in a little understood way. Here we present a systematic review of the peer-reviewed literature to identify the drivers of urban pollinator populations and pollination. A total of 141 studies were reviewed and qualitatively analyzed. Pollinator responses to urbanization were contrasting. We contend that positive responses were often associated with urban sprawl, i.e. moderate levels of urbanization of rural, mostly agricultural land below 50% impervious surface, whereas high levels of densification with high percentages of sealed and built-up area (above 50%), largely led to pollinator declines and loss of pollination services. Further, urbanization generally reduced pollinator diversity when compared to natural or semi-natural areas, but enhanced it when compared to intensified agricultural landscapes. In addition, pollinator responses were commonly highly trait- and scale-specific. Cavity nesters and generalist species usually profited more from urbanization than ground nesters and specialists. Overall, urban pollinator communities still seem to provide sufficient pollination services to wild vegetation and crops. Pollinator diversity generally increased with the amount of urban green spaces at the landscape scale, and locally with availability of nesting resources and flowering plants. Positive effects of floral additions were largely independent of the plant’s origin, whether native or non-native. Only a few studies included landscape configuration. Likewise, abiotic urban drivers, e.g. heat island effects and air and light pollution, remain little studied. Tropical and developing regions, most heavily impacted by current and future urbanization, are strongly underrepresented. We conclude that biodiversity-friendly urbanization can make a valuable contribution to pollinator conservation, in particular in face of the continued intensification of rural agriculture.

Land-use change is considered one of the main causes of the observed population decline of pollinators. Pollinators are essential for the reproduction of wild and cultivated plant species. Protected areas contribute to pollinator conservation by providing key nesting and foraging habitats. We estimate how much of the pantropical pollination service is currently within terrestrial protected areas. We used publicly available global datasets to generate variables known to predict pollinator abundance and have built a pantropical spatially explicit model of the pollination service. Our results suggest that 80% of tropical protected areas contribute to crop pollination. Protected areas (PAs) that currently do not contribute to crop pollination may contribute in the future as agriculturalisation continues and they begin to neighbour croplands. The remaining PAs provide habitat for pollinators of wild plants, alongside many other ecosystem services. Small-sized PAs provide higher pollination service per unit area than large ones due to their greater proximity to crops in general and their greater perimeter per unit area. These small PAs also tend to be under greater anthropogenic pressure than large-sized tropical PAs. We suggest the role of pollination services to croplands from PAs be considered alongside other ecosystem services in PA management decisions.

Necessity of pollinators in ecosystem services and their decline has raised concern for their conservation both in farm lands and urban areas. With the aim of conservation of these pollinators, we initiated developing a pollinator garden at Yelahanka Campus of ICAR-National Bureau of Agricultural Insect Resources in an area of one acre by planting over 50 diverse plant species. Thirty-nine different species of bees were documented from the flora of the pollinator garden. Out of the thirty-nine species of bees, nineteen species of bees belong to non-apis families viz., Megachilidae and Halictidae. Apart from foraging on the flowers, the solitary bees like Megachile sp. were found nesting in the stems, fallen dried flowers in the pollinator garden. The bees were found year-round foraging upon the flora in the pollinator garden. Pollinator garden is a way to in-situ conserve the native bees to sustain the valuable pollination service in various crop plants provided by them.

Insect pollination is an economically important ecosystem service that depends heavily on wild pollinators. Landscape transformation caused by conversion to agriculture threatens habitats of wild pollinators, reducing their potential to provide ecosystem services. The landscape in Jambi Province, Sumatra, Indonesia, is an example of a region undergoing landscape transformation, from biodiverse natural forests, to intermediate land uses such as fallow shrubland and jungle rubber, to monospecific oil palm plantations. My dissertation explores how transitions between these land uses impact pollinator biodiversity and ecosystem functions and services. I consider different facets of this interface: the impacts of adjacent forest on pollination services to oil palm; mechanisms driving ecosystem functions and services following agroforestry enrichment within oil palm; and landscape-scale comparisons quantifying interacting local and landscape effects on a native pollinator species. My first chapter reviews the state of the knowledge of oil palm pollination by insects. I conducted a systematic review of biotic and abiotic drivers of oil palm pollination and pollinator populations. I present the current understanding of the globally introduced West African Weevil (Elaeidobius kamerunicus), whose regional population fluctuations have negatively impacted yield and resilience, as well as other potential pollinator species endemic to particular growing regions. Based on my review, I describe specific issues concerning biotic, management, and climate drivers of pollination that should be the focus of future oil palm pollination research. In my second chapter, I examine the role that natural habitat can play as a source of pollination ecosystem services and ecological spillover effects in an oil palm field experiment. I compared treatments controlling visitors and pollination of female oil palm inflorescences over a distance gradient from an adjacent forest border. I found that exclusion of all visitors significantly decreased fruit set compared to other treatments, confirming insect pollination is necessary for adequate yield. Forest proximity had a significant positive effect on fruit set when large visitors were excluded. This effect was not significant for treatments that minimized pollinator contributions, suggesting this trend was not due to abiotic factors. However, insect abundances associated with oil palm inflorescences were not strongly related to distance from forest, and only E. kamerunicus had a significant relationship with fruit set. These results could suggest that non-consumptive ecological spillover from forests may influence oil palm pollination, though more experimental work is needed to identify these interactions. In my third chapter, I explore how enriching the oil palm agricultural matrix with up to six tree species played a role in driving insect-mediated ecosystem functions. Within a plantation-scale, long-term oil palm biodiversity enrichment project, I disentangled the direct and indirect effects of enrichment on services (pollination, biocontrol) and disservices (herbivory) using random partition analysis and structural equation models. These models indicate that changes in canopy openness, driven by enrichment treatments, played an important role in ecological patterns at multiple levels of interaction. These had effects on herbivorous insects and pollinators, the latter of which had a positive effect on the fruit production of phytometer plants (Capsicum annuum) placed in the plots. Our results show that, even in early stages of ecological restoration of oil palm, ecosystem functions and services can be affected. These effects are mediated by decreasing canopy openness; however, these relationships may change as enrichment communities continue to develop. In my fourth chapter, I examine the counterbalancing roles of local land use and amount of landscape habitat in pollinator survival and growth, using the native stingless bee Tetragonula laeviceps as a focal species. I established three colonies in 40 plots within Jambi’s transformation landscape, selecting from four predominant habitat types (degraded primary forest, shrubland, rubber plantation, and oil palm plantation) and controlling for a gradient of natural habitat (i.e., forest and shrubland) composition in a 500 m radius. I found that hives with higher local flower species richness had more pollen stores, which in turn was associated with increased bee and colony size. Colonies in structurally complex habitats such as forest and rubber plantations had lower mortality and greater gains in hive size than colonies in open habitats such as oil palm and shrubland; however, open habitats had higher flower species richness and abundance. Open habitats, which are increasing with rainforest conversion, reduce suitable nesting habitat but may increase floral resources in the landscape. Considering the key pollinating function of stingless bees, understanding how this trade-off translates to landscape and population scales will be critical in light of the continued deforestation crisis in the tropics. In summary, understanding and protecting the resources supporting pollination are critical to improving the sustainability of oil palm and can support the livelihoods of people living in the landscape. The impact of habitat loss from agriculture conversion can adversely impact wild pollinator populations through the loss of suitable habitats, as I observed with T. laeviceps, but also changes the flowering resource landscape. In my review of oil palm pollination, I show that a better understanding of biodiversity and landscape drivers of pollination of oil palm itself is needed. My own oil palm field experiment demonstrates how natural habitat and biodiversity may interact positively with oil palm production. I show in my experiments within the oil palm biodiversity enrichment project that tree biodiversity enrichment can indirectly influence pollination services and ecosystem functions, even at an early stage. However, the ecosystem services and disservices affected by ecological restoration will continue to change as the ecological community develops. Our task in future research will be to continue to disentangle these relationships with the aim of recovering or preserving biodiversity and ecosystem function while informing sustainable ecological strategies for farmers and land managers. | 2022-10-04

Population declines of pollinators constitute a major concern for the fate of biodiversity and associated ecosystem services in a context of global change. Massive declines of pollinator populations driven by habitat loss, pollution, and climate change have been reported, whose consequences at community and ecosystem levels remain elusive. We conducted a mathematical modeling and computer simulation study to assess the dynamic consequences of pollinator declines for the biodiversity of plants and pollinators. Specifically, we evaluated the effects of increased mortality and decreased carrying capacity of specialist vs. generalist and effective vs. ineffective pollinators visiting specialist vs. generalist plants on long-term community biomass and species persistence. Our results reveal that increased larval mortality and increased competition for space among larvae had the greatest impacts on the decline of pollinator diversity. In contrast, the largest sustained decreases in pollinator biomass were driven by increased adult mortality in spite of a small increase in pollinator species persistence. Decreased pollinator diversity led in turn to decreased plant diversity. Attacking pollinators with high degree and connected mostly to low-degree plants produced the greatest losses of plant diversity. Pollinator effectiveness had no noticeable effect on persistence. Our results illuminate our understanding of the consequences of pollinator declines for the maintenance of biodiversity. | Fil: Ramos Jiliberto, Rodrigo. Universidad Mayor; Chile | Fil: Moisset de Espanés, Pablo. Centre for Biotechnology and Bioengineering; Chile | Fil: Vazquez, Diego P.. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; Argentina

Biodiversity loss affects the functioning of all ecosystems, including agroecosystems, through the loss of essential ecosystem services. Supporting populations of organisms providing those services though vegetation diversification schemes is a promising tool to maintain a high agricultural production as well as ecosystem health. Nevertheless, those schemes show contrasted and unexplained results. This work aims at understanding how increased cultivated diversity impacts pollinator and natural enemy community structure and functioning by considering interactions within and among those groups. Our results show a community shift in response to increased resource diversity, possibly leading to negative interactions. In aphid – parasitoid – hyperparasitoid trophic foodwebs, resource diversification seemed to increase hyperparasitism and competition among primary parasitoids, that could explain the limited aphid control. The intensive use of cultivated flowers by the domestic honeybee seemed to limit wild pollinator use of this resource. Moreover, we highlighted a decrease in aphid parasitism rate in response to high pollinator abundances, suggesting for the first time possible negative interactions among those groups. Rethinking agricultural landscapes considering resource use of each group at different spatio-temporal scales as well as interactions within and among groups is essential to optimize simultaneously several ecosystem services and reach more autonomous and resilient agricultural production. | La crise de la biodiversité affecte le fonctionnement de tous les écosystèmes, notamment agricoles, via une perte des services écosystémiques. Favoriser les populations d’organismes à l’origine de ces services via des stratégies de diversification végétale est un levier prometteur pour maintenir une production agricole élevée ainsi que la santé des écosystèmes, mais les résultats obtenus sont variables et peu expliqués. L’objectif de cette thèse est de comprendre comment l’augmentation de la diversité cultivée impacte la structure et le fonctionnement des communautés de pollinisateurs et d’ennemis naturels en considérant leurs interactions. Nos résultats montrent que la diversification des ressources modifie la composition des communautés, pouvant mener à des interactions négatives. Dans les réseaux trophiques puceron – parasitoïde – hyperparasitoïde, la diversification semble avoir augmenté l’hyperparasitisme et la compétition entre les parasitoïdes primaires, ce qui expliquerait un contrôle des pucerons limité. L’utilisation massive des fleurs cultivées par les abeilles domestiques semble limiter l’utilisation de cette ressource par les pollinisateurs sauvages. De plus, nous avons observé une diminution du service de régulation des pucerons par les parasitoïdes en réponse à une forte abondance de pollinisateurs, signalant pour la première fois de possibles interactions négatives entre ces deux groupes. Optimiser plusieurs services écosystémiques simultanément demande de repenser les paysages agricoles en considérant l’utilisation des ressources de chaque groupe d’organismes à différentes échelles spatio-temporelles ainsi que les interactions au sein et entre ces groupes.