Pollinator Habitat Research Articles

Valuation of pollination services from habitat management: a case study of utility scale solar energy facilities in the United States

Creating and maintaining pollinator habitats following the ecological infrastructure concept in degraded or unutilized land, such as solar energy facilities, is a practical way to synergistically advance the food, energy, and ecology nexus. Given the large land-use requirements for solar farming—the fastest growing renewable energy technology–considerable attention has been focused on strategies to maximize multiple ecosystem services. In this study, we coupled the principles of agronomy and ecology with economics and integrated national-scale data on crops, pollinators, and solar facilities to identify locations for creating pollinator habitats and estimating the economic value of pollination from the habitats. We examined opportunities for pollination services from pollinator-friendly utility-scale solar facilities adjacent to 42 million hectares of pollination-dependent crops in the conterminous United States at high resolution of 1 ha. We used the net income method to estimate the potential economic value of creating habitat in the land adjacent to solar facilities in the eight states with the greatest number of solar installations. Creating pollinator habitats at the 217 utility-scale solar facilities in these states could support adjacent 80,000 hectares of high pollinator dependent crops, which could potentially generate a pollination value of $120 to $264 million USD. The location-specific information and high-resolution maps generated for the United States demonstrate integration of grey and green infrastructure to support the food, energy, and environment nexus.

Response of Common Wildflower Species to Postemergence Herbicides

Wildflowers attract wildlife, increase pollinator habitat, and enhance the aesthetic value of the landscape. Wildflower establishment is increasingly part of an effort to reduce maintained turfgrass on golf courses, lawns, and other maintained environments. Weed competition decreases wildflower establishment and results in poor long-term stands. Research was conducted in a controlled environment to investigate the tolerance of wildflower species to common postemergence herbicides. Wildflower species included California poppy (Eschscholzia californica Cham.), common sunflower (Helianthus annuus L.), cornflower (Centaurea cyanus L.), garden coreopsis (Coreopsis lanceolata L.), partridge pea [Chamaecrista fasciculata (Michx.) Greene], plains coreopsis (Coreopsis tinctoria Nutt.), purple coneflower [Echinacea purpurea (L.) Moench], rosering gaillardia (Gaillardia pulchella Foug.), and violet prairie clover (Dalea purpurea Vent.). Herbicides evaluated were fluazifop at 0.28 kg⋅ha–1 a.i., mesotrione at 0.14 kg⋅ha–1 a.i., clopyralid at 0.29 kg⋅ha–1 a.i., bentazon at 0.56 kg⋅ha–1 a.i., halosulfuron at 0.053 kg⋅ha–1 a.i., and imazaquin at 0.42 kg⋅ha–1 a.i. An untreated check was included for comparison. Excessive damage (≥ 53% phytotoxicity) was observed on all wildflower species in response to clopyralid, except for California poppy. Fluazifop and bentazon were relatively safe (≤ 19% phytotoxicity, regardless of herbicide) on all wildflower species; however, bentazon resulted in ≥ 40% aboveground biomass reduction in several species. Common sunflower and garden coreopsis were susceptible to halosulfuron (37% and 73% phytotoxicity, respectively) and imazaquin (37% and 87% phytotoxicity, respectively), but on all other wildflower species, phytotoxicity was ≤ 18%. Although both halosulfuron and imazaquin only resulted in ≤ 18% phytotoxicity to purple coneflower, a 43% to 44% aboveground biomass reduction was recorded. Mesotrione was only safe on California poppy and cornflower (≤ 11% phytotoxicity and ≤ 24% aboveground biomass reduction). Results suggest high tolerance variability across herbicides and species considered, but may prompt new investigation of safety and utility within field and production scenarios.

Environmental Co‐Benefits of Maintaining Native Vegetation With Solar Photovoltaic Infrastructure

AbstractCo‐locating solar photovoltaics with vegetation could provide a sustainable solution to meeting growing food and energy demands. However, studies quantifying multiple co‐benefits resulting from maintaining vegetation at utility‐scale solar power plants are limited. We monitored the microclimate, soil moisture, panel temperature, electricity generation and soil properties at a utility‐scale solar facility in a continental climate with different site management practices. The compounding effect of photovoltaic arrays and vegetation may homogenize soil moisture distribution and provide greater soil temperature buffer against extreme temperatures. The vegetated solar areas had significantly higher soil moisture, carbon, and other nutrients compared to bare solar areas. Agrivoltaics in agricultural areas with carbon debt can be an effective climate mitigation strategy along with revitalizing agricultural soils, generating income streams from fallow land, and providing pollinator habitats. However, the benefits of vegetation cooling effects on electricity generation are rather site‐specific and depend on the background climate and soil properties. Overall, our findings provide foundational data for site preservation along with targeting site‐specific co‐benefits, and for developing climate resilient and resource conserving agrivoltaic systems.

Strategies for reducing inputs and emissions in turfgrass systems

AbstractTurfgrass systems (e.g., home lawns, commercial properties, golf courses, athletic fields, roadsides, sod farms, parks, and other green spaces) in the US employ 820,000 individuals, have a $60 billion economic impact, and cover nearly 2% (∼63,250 mi2; 163,800 km2) of the US. Turfgrass systems provide ecosystem services such as carbon sequestration, oxygen production, water and air purification, improved soil health, pollinator habitat, and evaporative cooling. Associated disservices with turfgrass systems include nutrient and pesticide leaching, greenhouse gas and particulate matter emissions, low plant diversity, and site‐specific, high water consumption. The goal of recent research efforts is to maximize the services and minimize the disservices by focusing on sustainability initiatives to develop best management practices such reducing management inputs (e.g., mowing, irrigation, fertilizer, and pesticides), incorporating pollinator‐friendly spaces, adopting new technologies, quantitatively assessing ecosystem services provided, minimizing energy inputs and greenhouse gas emissions, and increasing carbon sequestration. This part‐review, part‐management guide summarizes these efforts, identifies knowledge gaps, and outlines how turfgrass systems can adapt to and mitigate climate change.

Parametric design of an automated kinetic building façade using BIM: A case study perspective

Pollination plays a critical role in maintaining human life and its importance has been widely recognized by researchers. However, as the world population grows, construction activities have increased, leading to an expanded carbon footprint that has adverse effects on the environment. This has resulted in the loss of natural habitats for pollinators. To address these issues, this research aimed to design an innovative mixed-use building to promote biodiversity conservation. The building was designed to have global visibility and to combine various elements in different locations to achieve maximum functionality. Automated features were incorporated into the building's structure to enhance its efficiency. Throughout the project, experts were consulted to ensure the building met sustainability standards and the best site was selected. BIM was used as part of the research methodology to design the building and calculate its sustainability and energy-efficient elements. As a result, the building achieved Gold certification status and has made a significant contribution to green building and sustainability in the built environment. The final product not only addressed the biodiversity issue, by designing a building where honeybees and humans coexisted but also provided a new solution for future developments in sustainable design. To ensure that these efforts are successful, it is important for different sectors, including Architectural, Engineering, Construction, and Operations (AECO), to work together to create a more sustainable future for the planet.

B.Y.O. Bees: Managing wild bee biodiversity in urban greenspaces.

As cities become more populated and the density of urban development increases, local biodiversity is threatened. Urban greenspaces have the capacity to preserve pollinator biodiversity, but the quality of support they provide depends on greenspace landscape attributes, including the availability of pollinator habitat and foraging resources. Wild native bees provide important pollination services to urban ecosystems, yet relatively little is known about how urban landscape management influences pollinator community composition and diversity. Our study explores how wild bee communities are affected by greenspace and landscape-level features like pollinator management practices, in urban greenspaces in and around Appleton Wisconsin: a mid-sized urban community spanning more than 100 sq. km. We sampled and identified native bees periodically between late-May 2017 and mid-September of 2018 using standardized arrays of pan traps at 15 sites around the city. We classified greenspaces based on their level of development (urban or suburban) and whether they were managed or unmanaged for increasing wild pollinator diversity. We quantified floral species diversity, floral color diversity, tree species diversity, and proximity of sites to open water for each site and used remotely sensed satellite data from both the USGS National Land Cover Database (NLCD) and the Normalized Difference Vegetation Index (NDVI). All variables were tested as potential correlates of wild bee abundance and species richness. Active pollinator management sites supported higher levels of bee abundance and richness. Notably, active greenspace management (e.g. planting native wildflowers) was a stronger correlate of bee abundance and richness than greenspace size and other landscape-level attributes. Within-greenspace attributes such as floral diversity, tree diversity, and proximity to open water contributed positively to both bee abundance and richness. Based on these findings, we suggest that urban greenspaces may be managed more efficiently and cost-effectively by focusing resources on active management by planting wildflowers, removing invasive species, creating nesting habitat, and providing water resources, rather than simply expanding in area.

Effects of vegetation structure and environmental characteristics on pollinator diversity in urban green spaces

With accelerating urbanization, insect pollinators in urban ecosystems face challenges such as reduced pollen sources, habitat fragmentation, and damage to the nesting environment. Urban green spaces (UGS) are essential for the stability of pollinator communities. However, little is known about the relationship between vertical layer heterogeneity and horizontal layer complexity of vegetation structure in UGS and pollinator communities. The present study aimed to assess how vegetation structure and environmental characteristics shape the insect pollinator community in UGS. To this end, this study was conducted with seven typical vegetation types which were selected according to the biotope mapping classification system (BMCS) in the ring parks around Hefei City, in Anhui province, China. A total of 11,401 pollinators belonging to 6 orders and 34 families were identified during the eight-month survey. Among the seven habitats under the BMCS, mainly successional short-cut shrub and partly open green space, trees two- or multi-layered broad-leaved mixed forest and partly closed green space, and mainly successional tall grass and partly open green space were identified as high-quality insect pollinator habitats. According to the results of the generalized linear regression, the explanatory power of the four best-fitting generalised linear models is relatively high (over 77%). In four optimal models, the effect of vegetation structure on pollinator community was greater than that of environmental characteristics. The redundancy discriminant analysis showed that the flowering abundance of nectar plants, herb richness, and shrub coverage rate were the three most important factors influencing insect pollinator communities, with a cumulative explanatory power of up to 78.8%. Pollinator abundance was positively influenced by spontaneous herbs and low-intensity management. However, high-intensity management, low diversity of plants, low nectar plant richness, ignoring seasonal nectar plant configuration, and dense tree distribution could limit pollinator reproduction and population growth. These results reflect the status of insect pollinator community in UGS in Hefei city and present a possible direction for improving urban green habitats and plant configurations.

Shining a light on species coexistence: visual traits drive bumblebee communities.

Local coexistence of bees has been explained by flower resource partitioning, but coexisting bumblebee species often have strongly overlapping diets. We investigated if light microhabitat niche separation, underpinned by visual traits, could serve as an alternative mechanism underlying local coexistence of bumblebee species. To this end, we focused on a homogeneous flower resource-bilberry-in a heterogeneous light environment-hemi-boreal forests. We found that bumblebee communities segregated along a gradient of light intensity. The community-weighted mean of the eye parameter-a metric measuring the compromise between light sensitivity and visual resolution-decreased with light intensity, showing a higher investment in light sensitivity of communities observed in darker conditions. This pattern was consistent at the species level. In general, species with higher eye parameter (larger investment in light sensitivity) foraged in dimmer light than those with a lower eye parameter (higher investment in visual resolution). Moreover, species realized niche optimum was linearly related to their eye parameter. These results suggest microhabitat niche partitioning to be a potential mechanism underpinning bumblebee species coexistence. This study highlights the importance of considering sensory traits when studying pollinator habitat use and their ability to cope with changing environments.

Managed and unmanaged floral margins for the conservation of bee communities in intensive agricultural areas

Floral resources on crop field margins are a well-accepted measure to increase bee abundance in agricultural landscapes. However, studies have mainly focused on managed margins, while studies on the effect of unmanaged floral margins for the conservation of bees are still scarce. This work aims to test and compare the effects of three types of floral margins (managed herbaceous, managed shrubby, and unmanaged herbaceous) on the abundance and diversity of bees in order to propose a management strategy for the conservation of pollinating insects. Bee abundance was recorded by visual samplings in plots of 2 × 2 square meters over two years in the three margin types in four localities in southern Spain. The diversity of plant species and the flowers they supported were measured to explain the associated bee communities. Differences in the relative abundances of bee families and the number and abundance of bee genera were observed between margin types. Andrenidae was generally more abundant in the herbaceous margins regardless of whether these were managed or not. With the exception of the Halictidae, the majority of bees families (wild Apidae, Apis mellifera, Colletidae and Megachilidae) were more abundant in the managed than unmanaged margins. Moreover, the number of bee genera was higher in managed than in unmanaged margins. In addition, here we show that managed margins supported at least 30% more rare bee genera than unmanaged margins, highlighting the importance of floral margins management for the enhancement and conservation of bee communities, restoring habitat and food resources for pollinators across the Mediterranean agricultural landscape.

Theoretical Advances in the Ecology and Evolution of Mutualistic Interactions – Review of a Symposium (SYMP 14) Organized at ESA + CSEE 2022 Joint Meeting

Theoretical Advances in the Ecology and Evolution of Mutualistic Interactions – Review of a Symposium (<scp>SYMP</scp> 14) Organized at <scp>ESA</scp> + <scp>CSEE</scp> 2022 Joint Meeting

Sowing wildflower meadows in Mediterranean peri-urban green areas to promote grassland diversity

IntroductionThe increase of urban areas and their infrastructure network is homogenizing the landscape and threatening biodiversity and ecosystems functions and services. Wildflower meadows have a high biodiversity value and can prosper in degraded areas dominated by nitrophilous species, making them suitable to be used in peri-urban and urban areas to promote local flora, create habitat for pollinators and other small fauna, and increase overall biodiversity. Moreover, the application of wildflowers seed mixes suitable for rehabilitating anthropized environments should be restricted to native species of regional origin, and the results properly monitored. However, thorough monitoring of seed mixes evolution is uncommon. This study evaluates the effectiveness of a seed mix of wild native species developed to promote grassland diversity in Mediterranean peri-urban areas.MethodsThe study was divided into two sequential phases. Firstly, a preparatory phase consisted in developing two seed mixes and sowing them (autumn 2016) in ex-situ plots (three plots of 5 × 2 m2 per mix) at an experimental field to choose the one with the best performance. The second phase consisted of the in-situ application (autumn 2018) of the chosen seed mix by sowing 14 plots (10 × 2 m2) in pocket parks distributed along pedestrian trails of South Portugal. All plots were monitored through floristic surveys for two springs (ex-situ trials: 2017 and 2018; in-situ trials: 2019 and 2020).ResultsAll sowed species germinated in the in-situ plots over the first 2 years. The seed mix application positively contributed to the floristic community, generating a significant increase in the total species richness, diversity, evenness, and vegetation cover. The seed mix establishment did not require watering nor soil fertilizing and the mowing frequency was low (once in late spring), contributing to sustainable and low-cost management of these green areas.DiscussionThe tested seed mix promoted native flora diversity rapidly and seems suitable for use in peri-urban context under identical climate conditions. Given the small number of native seed mixes tested in the Mediterranean, this study represents a contribution toward improved management standards of native flora diversity in Mediterranean green urban and peri-urban areas.

Testing the accuracy of a Rights-of-Way pollinator habitat scoring system

Habitat loss is a major cause of pollinator declines, and there is increased interest by the public in creating pollinator-friendly lands. Electric and transportation rights-of-way (ROW) present an opportunity for large amounts of land to be managed to support pollinators. The Rights of Way as Habitat Working Group developed a pollinator habitat scorecard with the goal of establishing a consistent valuation method for pollinator habitat quality in ROWs. In this study, we tested how well the pollinator habitat score aligns with several measures of pollinator biodiversity in electric transmission ROWs. We used pan traps and timed observations to quantify the communities of lepidopterans and bee hymenopterans at 12 ROW sites in Illinois, USA. The 12 study sites were divided across four geographical locations in the greater Chicago metropolitan area, with each location including three sites managed in different ways: turf-grass lawn, restored prairie, and weedy old-field. We found that the pollinator habitat score was not a significant predictor of bee and lepidopteran pollinator biodiversity. However, the pollinator habitat score did differ significantly among the ROW management types, with lawn sites receiving lower scores than prairie or old-field sites. These results indicate that the pollinator habitat scorecard may not, in its current form, be appropriate for comparing pollinator biodiversity among sites, although it does capture differences in pollinator resource availability at a local scale. We suggest that the scorecard as currently designed may be more useful in monitoring temporal changes at individual sites rather than making spatial comparisons among sites. We also recommend that future studies continue to examine ways to make the pollinator habitat scorecard a more universally applicable tool, because an accurate, simple scorecard would provide valuable information to ROW land managers.

Planted pollinator habitat in agroecosystems: How does the pollinator community respond?

Pollinators are important both ecologically and economically. Nonetheless, documented pollinator population decline threatens ecosystem functioning and human well-being. In response, conservation methods such as augmented pollinator habitat are becoming popular tools to combat pollinator losses. While previous research has shown added habitat can benefit bee communities, there are still aspects of the habitat implementation that require further research, particularly how this will impact bee communities in real-world settings beyond researcher-led efforts. In our study, we use a 2016 initiative mandating the planting of pollinator habitat on research stations across North Carolina, United States to act as an outdoor laboratory to investigate this exact question. From 2016 to 2018, we found significant increases in bee abundance and diversity. However, these increases depended on the quality of habitat, with areas of higher flower cover and diversity supporting larger, more diverse bee communities. Although the habitats positively supported bee communities, we found that resources within the habitats were lower later in the sampling season, highlighting the need of developing seed mixes that include late season resources. Weedy plants were documented to establish within the habitats, demonstrating the need for regular upkeep and maintenance of pollinator habitat in order to appropriately support bee communities. It is likely that planting pollinator habitat will not be a one-size-fits-all conservation solution, as bee species can respond differently to some habitat characteristics. Future long-term studies on pollinators will be important as natural fluctuations in bee populations may limit findings and many knowledge gaps on native bees still persist.

Current Impediments for New England DOTs to Transition to Sustainable Roadside Practices for Strengthening Pollinator Habitats and Health

Government agencies whose work impacts the environment have sought more sustainable policy changes that require the use of native plants for revegetation. However, New England DOTs have encountered hurdles in attempts to transition from using cool-season turfgrass to implementing the more complicated management practices required to establish native plant communities. Two of the most significant barriers have been the slow transition to mainly using native plants for revegetation and the lack of genetically appropriate ecotypic native plant material (ENPM) produced in the Northeast. Growers of ENPM have resisted increasing production because they struggle to gauge demand due to substantial communication gaps between local producers and end users. Therefore, we organized focus groups with New England state DOTs, Departments of Environmental Protection, and Fish and Wildlife Services to determine their demand for ENPM and to explore their relationships with producers. We determined that the subcontracting of DOTs hinders their ability to develop relationships with producers because it leaves seed source selection in the hands of third parties. Another impediment was found to be the resistance of some maintenance departments to adopt sustainable management practices, such as reduced mowing. In summary, we determined that DOTs would benefit from establishing more direct relationships with producers to communicate their ENPM needs.

Bee–plant interaction and community response along an urbanization gradient

Abstract Elucidating bee response to urbanization is essential to promoting pollinator diversity in cities especially considering such landscapes are projected to expand to support future global populations. To determine how bee community composition and plant–pollinator interactions respond to urbanization, 29 sites representing three urban categories (high, medium and low urbanization) were monitored biweekly from May through early October in Toronto, Canada. Bees were collected passively using pan and blue vane traps as well as actively using aerial nets and vacuums to compare community structure and plant–pollinator networks among urban categories. Functional traits such as dietary breadth, behaviour, nesting substrate and native or non-native status were also examined to determine how landscape influences bee community assemblages. In total, 5477 bees, comprising 26 genera and 164 species, were represented in this study. The urban landscape was largely supportive of species within the family Apidae and Halictidae as well as ground nesting, native and generalist species. Overall, community composition was affected by urban landscape characteristics such as percent tree cover and impervious (i.e. paved and built) surface surrounding sites; however, bee richness and abundance were significantly influenced by plant richness and not by landscape variables. A total of 3267 interactions were observed throughout the study region with characteristics of plant–pollinator networks remaining consistent along the urban gradient with a few floral host plants such as Solidago dominating interactions in certain urban contexts. These results provide important land use and floral host information for targeting pollinator conservation and habitat restoration.

Citizen science initiatives increase pollinator activity in private gardens and green spaces

Wild insect pollinators are essential to cultivated and natural ecosystems globally. Today, many pollinator species are declining. One reason is a general lack of flowering habitats at landscape scales. However, urban areas, including private gardens, may provide flowers, and constitute beneficial habitats for pollinators. Here, we evaluate the ecological outcomes of a citizen science campaign run by the Swedish Society for Nature Conservation (SSNC) (called “Operation: Save the bees”), encouraging citizens to incorporate interventions beneficial to wild pollinators (garden meadows, flower plantings, and bee hotels) in their gardens. Data on insect observations and flowering plants were collected through online questionnaires at the end of the growing season. In total, we received 3,758 responses for the three interventions. We found that participants were more likely to observe many pollinators (as opposed to few or none) in more species rich garden meadows, and in larger and older plantings. The surrounding environment also affected pollinator abundance: fewer pollinators were observed in plantings in dense urban areas. Direct counts of pollinators during 10-min surveys correlated strongly to the simplistic abundance assessment (none, few, or many insects seen over the summer season). Bee hotel occupancy was positively related to local flower availability and bee hotel age. Smaller nest holes (&amp;lt;10 mm) were more occupied than larger holes (11–15 mm) and hotels in rural gardens and natural/semi-natural sites were more occupied than those in urban gardens. This study demonstrates that flower-rich private gardens provide integral habitat for wild pollinators and that citizen science programs can provide a tool for implementing and evaluating conservation practices. However, longer lasting commitment resulting in older interventions are preferable and should be encouraged in future campaigns.

Effects of replacing corn silage with alfalfa haylage in growing beef cattle diets on performance during the growing and finishing period.

Corn silage is the predominant mechanically harvested forage source for feedlot cattle production in the United States because of high yield. Alternatively, because of multiple cuttings per year and lower annual cost, the use of alfalfa or other forages, may increase opportunities for manure spreading, perennial soil cover, pollinator habitat, and greater carbon sequestration. The objective of this trial was to determine the feeding value of alfalfa haylage when replacing corn silage in growing cattle diets. One-hundred-sixty-five Angus crossbred steers [326 ± 51 kg of body weight (BW)] were blocked by initial BW and randomly assigned to one of 28 pens at the University of Minnesota feedlot. Pens were randomly assigned to dietary growing treatments. The control diet was comprised of (DM basis) 50% corn silage, 19.25% rolled corn grain, 19.25% high moisture corn, 7% dried distillers grains plus solubles, and 4.5% liquid supplement (corn silage control, CS Control). For alfalfa haylage (AH) diets, AH substituted corn silage at 33% (AH 33), 66% (AH 66), or 100% (AH 100). Growth performance measurements [dry matter intake (DMI), average daily gain (ADG) and gain to feed (G:F) ratio] were assessed for 42 to 70 d depending on BW block. Afterwards, steers were fed a common finishing diet until harvested. There was a linear increase in DMI (P < 0.01) with increasing AH inclusion. Replacing CS with AH linearly decreased (P ≤ 0.05) ADG and G:F. No differences (P ≥ 0.10) were observed in finishing performance or carcass traits. Results from this study demonstrated that greater substitution of corn silage with alfalfa haylage in growing diets resulted in greater intake but reduced rate of gain and gain:feed. Despite slower rate of gain, cattle fed alfalfa haylage at increasing proportions during the growing period were able to compensate in BW gains during the finishing period and reached harvest weight and backfat thickness at similar days on feed than those fed corn silage. Based on these results the energy value of corn silage and alfalfa haylage were 3.05 and 2.39 Mcal ME/kg of DM, respectively, when included at 50% of the diet DM.

Persistence and quality of vegetation cover in expired Conservation Reserve Program fields

AbstractFor nearly 40 years, the Conservation Reserve Program (CRP) has implemented practices to reduce soil erosion, improve water quality, and provide habitat for wildlife and pollinators on highly erodible cropland in the United States. However, an approximately 40,470 ha (10 million acres) decline in enrolled CRP land over the last decade has greatly reduced the program's environmental benefits. We sought to assess the program's enduring benefits in the central and western United States by (1) determining the proportion of fields that persist in CRP cover after contracts expired, (2) identifying the type of agricultural production that CRP fields shift to after contract expiration, (3) comparing the vegetation characteristics of expired CRP fields that are persisting in CRP‐type cover with enrolled CRP fields, and (4) identifying differences in management activities (e.g., haying, grazing) between expired and enrolled CRP fields. We conducted edge‐of‐field vegetation cover surveys in 1092 CRP fields with contracts that expired ≥3 years prior and 1786 currently enrolled CRP fields in 14 states. We found that 41% of expired CRP fields retained at least half of their area in CRP‐type cover, with significant variation in persistence among regions ranging from 19% to 84%. When expired fields retained CRP vegetation, bare ground was low in all regions and grass cover was somewhat greater than in fields with current CRP contracts, but at the expense of forb cover in some regions. Evidence of more frequent management in expired CRP fields may explain differences between active and expired CRP fields. Overall, there is clear evidence that CRP‐type cover frequently persists and provides benefits for more than three years after contract expiration. Retaining CRP‐type cover, post‐contract, is an under‐recognized program benefit that persists across the central and western United States long after the initial retirement from cropland.

Invited Review: Ecosystem services provided by grasslands in the Southeast United States

This review describes ecosystem services (ES) obtained from grasslands within the southeastern United States. In addition, future direction and the importance of these ES to sustain productive agroecosystems are de- scribed. Results from published studies investigating various ES provided by grasslands within the southeastern United States are summarized in this article. Ecosystem services can be classified into 4 categories: provisioning, regulating, supporting, and cul- tural. Grasslands in the southeastern United States range from wet prairies in Florida, to transitional grasslands emerging from tallgrass prairie and longleaf pine ecosys- tems into coastal marshes in Texas. Provisioning ES from grasslands include animal products, timber, fruits, pods, and medicinal products. Supporting and regulating ES in- clude nutrient cycling, biological nitrogen fixation, water catchment and purification, recharge of aquifers, climate regulation, primary productivity, habitat for wildlife and pollinators, and biodiversity. Grasslands are also impor- tant for aesthetic and cultural ES, including hunting leases and recreational parks. Grasslands in the southeastern United States have decreased due to urban- ization, rising livestock production costs, and decreases in seed resources. Providing ES assessments will be impor- tant to assign value to grassland ecosystems, especially to increase adoption of novel management practices that may enhance delivery of ES. Remote sensing, machine learning, and artificial intelligence are promising tools to scale up the measurement of ES at landscape and watershed levels. In the future, ES will likely be a more prominent component of agroecosystems, and payment mechanisms will become more common to compensate landowners for the benefit they provide for the entire society.

Intercrops as foraging habitats for bees: Bees do not prefer sole legume crops over legume-cereal mixtures

Enhancing crop diversity is an option to make agriculture more sustainable and biodiversity friendly. Intercropping grain legumes together with cereals leads to higher crop diversity and has a broad range of agronomic and ecological benefits. However, sole crop stands of grain legumes might be richer in floral resources than grain legume-cereal intercrops and thus are probably more useful to mitigate the lack of flower resources in agricultural landscapes, which is a main driver of pollinator decline. Yet, little is known about differences between both cropping systems and different legume genotypes in terms of attractiveness for pollinators and how these differences moderate the pollinators’ foraging behavior and consequences for grain legume yields. In a field trial, we analyzed the abundance of flower visiting insects, the foraging behavior of pollinators and related effects on grain yield per plant across six different faba bean genotypes (Vicia faba L.) grown as sole crops or as intercrops with wheat. As foraging behaviors, we considered legal flower visits (i.e. frontal visits) and illegal flower visits (i.e. nectar robbing through bite holes). We recorded characteristics of V. faba genotypes on crop stand level (V. faba plant height, number of V. faba inflorescences and leaf area index (LAI)). V. faba-wheat intercrops and sole crop stands of V. faba were equally attractive foraging habitats for pollinators, implying that intercrops are as suitable as sole crops to mitigate the lack of floral resources. Yield per V. faba plant was positively affected by bee pollination, with this effect being determined by the number of illegal flower visits, suggesting that this foraging strategy does not adversely affect V. faba yields and even has a positive effect. Intercrops had higher yields per V. faba plant than sole crop stands of V. faba, indicating agronomic advantages of this farming practice. Although V. faba genotypes differed in their plant traits, these differences could not explain shifts in the number of flower visiting insects. However, illegal flower visits increased with a higher number of inflorescences whereas the number of legal flower visits declined. Based on our small-scale experiment, we conclude that the use of V. faba-wheat intercrops brings agronomic benefits while serving as a foraging habitat for pollinators that proved to be as attractive as sole crop stands of V. faba.