Pollinator Habitat Research Articles

Native bee Pollination Ecosystem Services in Agricultural Wetlands and Riparian Protected Lands

Many freshwater wetlands and riparian systems are protected within agricultural landscapes. Yet, pollinator ecosystem services are seldom considered key ecosystem services provided by these conservation easements. The purpose of this study is to explore the extent of protected aquatic lands to provide pollination ecosystem services by assessing pollinator abundances, crop yield changes, and value estimations of increased soybean yields from a subset of common native solitary bees. We created a novel geodatabase of United States Department of Agriculture (USDA) conservation easements and used this database in the InVEST crop pollination model to model wild solitary bee pollination. We then estimated the monetary value of yield increases provided by pollinators. We found that wetland uplands provided the greatest potential for pollination services for ground nesting bees, followed by herbaceous and forested riparian respectively. Stem nesters preferred forested riparian, then upland habitats. In soybeans fields, we found wild pollinators can provide up to 5.5% yield response from current private aquatic conservation lands. The current landscape is not optimized to use wetlands and riparian conservation lands as pollinator habitat, but these results suggest protected aquatic lands can sustainably increase wild pollination services to agricultural crops if landscapes are managed, protected, and optimized with pollinator services as co-benefit.

Best management practices for bee conservation in forest openings

AbstractNative bees are an ecologically diverse group of pollinators in global decline due at least in part to invasive species, pesticides, and habitat loss. Although guidelines exist for land managers to restore pollinator habitat, these “best management practices” (BMPs) include other pollinator taxa that may have different requirements than bees, do not give particular attention to rare bee species, or describe practices that are impractical for land managers. Using co‐production science, our team of land managers and researchers sampled bee communities in 100 wildlife openings on six National Forests (NF) within the Great Lakes Basin of the United States during 2017–2019. We found that bee communities responded to site factors and management practices, including prescribed fire, mechanical methods (e.g., felling, brushhogging, mowing), herbicides, and pollinator plantings. Bee abundance, diversity, and rarity were strongly related to soil properties, landscape context, and the plant community, including small‐statured woody species, which collectively informed our BMPs. For instance, mechanical treatments were most beneficial for openings with clayey or organic soils while prescribed fire was most effective in openings with well‐drained soils. Our BMPs highlight effects of treatment combinations, including negative effects on rare species when herbicides were combined with plantings and positive effects on abundance and rare species when prescribed fire was combined with mechanical treatments. Since our BMPs were generated in collaboration with land managers, they better conform to their needs and constraints, contributing to more effective native bee conservation.

Species traits, landscape quality and floral resource overlap with honeybees determine virus transmission in plant-pollinator networks.

Emerging infectious diseases pose a threat to pollinators. Virus transmission among pollinators via flowers may be reinforced by anthropogenic land-use change and concomitant alteration of plant-pollinator interactions. Here, we examine how species' traits and roles in flower-visitation networks and landscape-scale factors drive key honeybee viruses-black queen cell virus (BQCV) and deformed wing virus-in 19 wild bee and hoverfly species, across 12 landscapes varying in pollinator-friendly (flower-rich) habitat. Viral loads were on average more than ten times higher in managed honeybees than in wild pollinators. Viral loads in wild pollinators were higher when floral resource use overlapped with honeybees, suggesting these as reservoir hosts, and increased with pollinator abundance and viral loads in honeybees. Viral prevalence decreased with the amount of pollinator-friendly habitat in a landscape, which was partly driven by reduced floral resource overlap with honeybees. Black queen cell virus loads decreased with a wild pollinator's centrality in the network and the proportion of visited dish-shaped flowers. Our findings highlight the complex interplay of resource overlap with honeybees, species traits and roles in flower-visitation networks and flower-rich pollinator habitat shaping virus transmission.

Automating field‐based floral surveys with machine learning

Abstract The abundance and diversity of flowering plant species are important indicators of pollinator habitat quality, but traditional field‐based surveying techniques are time‐intensive. Therefore, they are often biased due to under‐sampling and are difficult to scale. Aerial photography was collected across 10 sites located in and around Rouge National Urban Park, Toronto, Canada using a consumer‐grade drone. A convolutional neural network (CNN) was trained to semantically segment, or identify and categorize, pixel clusters which represent flowers in the collected aerial imagery. Specifically, flowers of the dominant taxa found in the depauperate fall flowering plant community were surveyed. This included yellow flowering Solidago spp., white Symphyotrichum ericoides/lanceolatum and purple Symphyotrichum novae‐angliae. The CNN was trained using 930 m2 of manually annotated data, ~1% of the mapped landscape. The trained CNN was tested on 20% of the manually annotated data concealed during training. In addition, it was externally validated by comparing the predicted drone‐derived floral abundance metrics (i.e. floral area (m2) and the number of floral patches) to the field‐based count of floral units estimated for 34 4 m2 plots. The CNN returned accurate multiclassification when evaluated against the testing data. It obtained a precision score of 0.769, a recall of 0.849, and an F1 score of 0.807. The automated floral abundance counting yielded estimates that were strongly correlated with field‐based manual counting. In addition, flower segmentation using the trained CNN was time‐efficient. On average, it took roughly the same amount of time to segment the flowers occurring in an entire drone scene as it took to complete the abundance count of a single quadrat. However, the training process, particularly manual data annotation, was the most time‐consuming component of the study. Practical implication: Overall, the analysis provided valuable insights into automated flower classification and abundance estimation using drone imagery and machine learning. The results demonstrate that these tools can be used to provide accurate and scalable estimates of pollinator habitat quality. Further research should consider diverse wildflower systems to develop the generalizability of the methods.

Compost incorporation and wildflowers introduction for stormwater infiltration and erosion-control vegetation cover establishment in post-construction landscapes

Urban and suburban development frequently disturbs and compacts soils, reducing infiltration rates and fertility, posing challenges for post-development vegetation establishment, and contributing to soil erosion. This study investigated the effectiveness of compost incorporation in enhancing stormwater infiltration and vegetation establishment in urban landscapes. Experimental treatments comprised a split-split plot design of vegetation mix (grass, wildflowers, and grass-wildflowers) as main plot, ground cover (hydro-mulch and excelsior) as subplot, and compost (30% Compost and No-Compost) as sub-subplot factors. Wildflower inclusion was motivated by their recognized ecological benefits, including aesthetics, pollinator habitat, and deep root systems. Vegetation cover was assessed using RGB (Red-Green-Blue) imagery and ArcGIS-based supervised image classification. Over a 24-month period, bulk density, infiltration rate, soil penetration resistance, vegetation cover, and root mass density were assessed. Results highlighted that Compost treatments consistently reduced bulk density by 19–24%, lowered soil penetration resistance to under 2 MPa at both field-capacity and water-stressed conditions, and increased infiltration rate by 2–3 times compared to No-Compost treatments. Vegetation cover assessment revealed rapid establishment with 30% compost and 60:40 grass-wildflower mix, persisting for an initial 12 months. Subsequently, all treatments exhibited similar vegetation coverage from 13 to 24 months, reaching 95–100% cover. Compost treatments had significantly higher root mass density within the top 15 cm than No-Compost, but compost addition did not alter the root profile beyond the 15 cm depth incorporation depth. The findings suggest that incorporating 30% compost and including a wildflower or grass-wildflower mix appears to be effective in enhancing stormwater infiltration and provides rapid erosion control vegetation cover establishment in post-construction landscapes.

A simple method to map pollination ecosystem services potential in urban lawns

Urban areas have detrimental impacts on the ecosystems. Nevertheless, they still supply many ecosystem services (ES), such as Pollination, in different urban green spaces (UGS). Lawns are among the most degraded UGS due to very high human impact. Still, flowers such as Dandelions (Taraxacum officinalis) live in these spaces. These flowers are considered a suitable habitat for pollinators. In this work, we develop a methodology to map Pollination ES potential in urban lawns using an Unmanned Aerial Vehicle. A detailed protocol was developed using high-resolution images, consisting of orthomosaic creation, flower vectorisation, field validation, and finally, Pollination ES potential mapping using Kernel and Point Density. This method can be applied to urban lawns and grasslands in Spring and Summer.•A novel method was developed to map pollination potential in lawns.•Dandelions (Taraxacum officinale) were mapped using UAV high-resolution images.•The method is helpful to identify areas with pollination potential in urban lawns.

Ecosystem services in mountain pastures: A complex network of site conditions, climate and management

Mountain pastures offer a multitude of ecosystem services (ES) such as fodder for ruminants, habitat for pollinators, climate change mitigation, aesthetic landscape for recreation, and biodiversity conservation. We aimed at analysing to which extend these ES are influenced by small-scale gradients of climate, site conditions and management – and to disentangle relationships among ES and the factors influencing them. Therefore, we quantified ES on six mountain summer farms in two contrasting regions in Switzerland: the Northern Alpine Foothills (lower elevation, higher precipitation, calcareous bedrock) and the Eastern Central Alps (higher elevation, lower precipitation, silicious bedrock). We measured six ES indicators (forage quantity, forage quality, carbon storage, colour abundance, resources for pollinators, plant diversity) and related them to explanatory factors of climate (temperature and precipitation), site conditions (soil fertility, soil acidity, terrain slope) and management (local grazing intensity, remoteness) in 66 study plots, i.e., 11 per farm. A holistic picture of the complex relationships among these factors was drawn by various statistical approaches: allometric line fitting, variance partitioning, and structural equations modelling. We found a huge heterogeneity of ES indicators and explanatory factors on each farm: the variability within farms was even higher than between regions. Variance partitioning and structural equations modelling demonstrated strongest influence of climate and site conditions and revealed trade-offs among ES indicators: High forage quantity and quality were associated with low plant diversity and grassland aesthetics, whereas diversity, aesthetics and pollinator resources were positively correlated with each other. ES indicators were explained by a range of climatic and topographic factors: High precipitation reduced plant diversity, whereas temperature increased forage quantity and quality; slope reduced soil fertility, forage quantity, forage quality and carbon storage; soil fertility in turn increased forage quantity; the farther away a pasture was from the main farm building, the lower was the forage quantity and the higher the plant diversity. Although allometric relations among local grazing intensity and ES indicators were strong, the direct influence of the management factors measured on ES was surprisingly small: Cattle preferred areas of high forage quantity and quality, and carbon storage was higher in these areas. On the other hand, places less visited by cattle offered more pollinator resources, and showed higher aesthetics and plant diversity. Trade-offs among ES prevent the realisation of all ES at the same place, but heterogeneity of mountain pastures allows to realise a broad bundle of contrasting ES on each individual summer farm.

Successful pollinator seed mixes include low grass density and high forb richness across a range of total seeding densities

Pollinator habitat restorations and enhancements are an important approach to mitigate pollinator declines due to habitat loss and other stressors. Foraging resources can be provided by wildflower plantings grown from seed mixes composed of pollinator‐friendly plant species. Despite clear evidence on the benefits of such plantings for bees and other pollinators, there is limited knowledge on how variation in multiple seed mix design parameters affects floral resources over time. Such information is crucial to improve the effectiveness of different habitat applications and to potentially lower seed costs, which remain an impediment to adoption. We conducted an incomplete factorial field experiment to test the impacts of density, diversity, and forb:grass ratio of seed mixes on floral resource availability and phenological coverage of the resulting plantings. We quantified floral area and phenological coverage over the whole blooming season for three consecutive years in replicated plots of wildflower mixes in two regions of the U.S.A, Northern California's Central Valley and Midwestern Tallgrass Prairie. When different seed densities were fully replicated (e.g. within high forb:grass seed ratios in Minnesota, or forb‐only seedings in California), seeding density had no further impact on floral area and floral phenological coverage.

Current trends in bee conservation and habitat restoration in different types of anthropogenic habitats

Recent declines in bee populations and ranges have been cause for concern due to the valuable pollination service that they provide. Several factors have been proposed to contribute to these declines, including habitat loss, pathogen spread, and pesticide usage, so many pollinator conservation schemes have involved the addition of pollinator-friendly habitat through wildflower plantings and artificial nesting sites. Because of this, many efforts have been made to enhance bee populations across different landscape types, including natural, agricultural, urban, and industrial areas. Many of these schemes have focused on providing habitat for bees and other animal pollinators in agricultural landscapes, but other managed areas, such as cities, suburbs, and industrialized areas may have untapped potential for pollinator conservation. Available green space can be enhanced to provide healthy forage and safe nesting sites for pollinators. As these areas are also often frequented by human residents, the needs and perceptions of people, as well as the potential benefits for pollinators, must be considered to ensure the success of pollinator conservation on anthropogenic habitats.

Testing a rapid assessment approach for estimating ecosystem service capacity in urban green alleys

Urban green infrastructure – the network of greenspaces across cities – provides ecosystem services that are important for urban sustainability. Because of this, cities are increasingly redeveloping underused alleys into green infrastructure to improve ecosystem service capacity. But it remains unclear if these green alleys are delivering on the promise of supplying particular ecosystem services. The indicators usually used within green infrastructure to measure ecosystem services may not be suitable for green alleys because of the unique structure, vegetative features and level of community engagement of these alleys. Here we developed and tested a rapid assessment approach to evaluate ecosystem service capacity appropriate for use by community members and practitioners, using a green alley network in Montréal (Canada) as a case study. We collected data on green alley vegetation, structural form and indicators of four ecosystem services (food provision, habitat for pollinators, anthropogenic noise regulation and air temperature regulation). We modelled the relationships between vegetation, structural form, and ecosystem services, to determine if these rapidly assessed features of green alleys are appropriate indicators to evaluate ecosystem service capacity. Our results show that a rapidly assessed measure of vegetative ground cover is strongly associated with habitat for pollinators, highlighting potential for vegetative ground cover as an indicator for this service. Rapid assessments of alley vegetation were not associated with air temperature or anthropogenic noise, contrasting the findings of previous studies. Lack of relationships between the explanatory variables and the four ecosystem services suggests that further research is required to untangle these complex relationships. Our research provides a starting point for developing indicators of ecosystem service capacity that are tailored specifically to the unique structure and features of green alleys, a crucial step in testing the efficacy of this increasingly popular sustainable development strategy.

Characteristics of urban milkweed gardens that influence monarch butterfly egg abundance

The eastern population of monarch butterflies (Danaus plexippus) has dramatically declined in the last few decades, which is largely attributed to a loss of milkweed habitat in agricultural areas. Residential land in metropolitan areas has the potential to provide a significant source of the milkweed needed to support the monarch population. To examine if and how urban milkweed patches can support monarch butterflies, we worked with community scientists in the Chicago metropolitan area to monitor monarch eggs and caterpillars in yards and community gardens. We hypothesized that the largest numbers of eggs (i.e. gardens that were most attractive to monarchs) would be observed in patches that were older, had a high abundance of milkweed, contained more than one species of milkweed including Asclepias syriaca (common milkweed) and/or A. incarnata (swamp milkweed), and had a large diversity of nectar plants. All patches were assessed at their peak egg count each year, which ranged from zero to 170 eggs in a given observation. To determine which characteristics were most influential to egg presence, we examined patches where eggs were present or absent during this peak observation. For abundance, we divided these peak observations into whether or not the egg counts were in the top 20% in a given year, excluding patches where eggs were absent, and assessed their patch characteristics. Our results show that patch age and presence of A. syriaca affected whether patches contained eggs or not. We also found that patches with the largest number of eggs observed tended to have A. syriaca, more milkweed plants, and a higher diversity of blooming plant species. The data we collected from community scientists in the Chicago area has enhanced our understanding of how urban gardeners can create effective breeding habitats for monarch butterflies. By planting Asclepias syriaca within its natural range, along with other native milkweed species and a diverse selection of flowering plants, individuals can create gardens that serve as excellent habitats for monarchs and other pollinators.

Seeding roadsides is necessary but not sufficient for restoring native floral communities

Abstract The plant community in roadside right‐of‐ways is an important component of transportation infrastructure. Revegetation after construction is an opportunity to improve the plant community and create pollinator habitat. However, native seed mixes are substantially more expensive than those used in conventional roadside plantings, and transportation agencies often lack resources for management. Here, we compare the actively flowering plant community across a growing season in roadside plots seeded with native seed mixes versus non‐native seed mixes in Minnesota, USA. Plots varied in age from 2 to 20 years old. We demonstrate that native seeded plots had more native flowering forbs than non‐native seeded plots, as native flowers were rare in the non‐native seeded plots. However, despite some native species establishing well, many species in native seed mixes had poor or non‐existent establishment. Furthermore, the native and non‐native seeded plots converged in the makeup of their floral communities after a few years; part of this pattern is due to colonisation of species that were never seeded at either type of plot. Practical implication. If the goal of revegetation is to produce diverse, native dominated floral communities in roadsides, agencies must invest more in long‐term management. Managers could also alter seed mixes to remove species that fail to establish, which would reduce the cost of the seed mix, but not the diversity of the plant community that ultimately establishes. The use of such streamlined seed mixes across more land area would increase the availability of pollinator habitat without substantially altering current budgets or management plans.

Little prairie under the panel: testing native pollinator habitat seed mix establishment at three utility-scale solar sites in Minnesota

As more land is being utilized for large-scale solar energy projects, there are increasing discussions from stakeholders on how to utilize land under solar panels to promote biodiversity. One path is to plant habitat beneficial to pollinators and other insects, but there have been few long-term studies that examine how different vegetation and seed mixes establish underneath solar panels. This study addresses a scientific gap to determine whether native pollinator seed mixes successfully establish over time under solar arrays using a systematic assessment of eight seed mixes planted at three utility-scale solar sites in Minnesota. We assess establishment with a percent native coverage metric, which is an assessment of native species observations compared to total observations during percent cover analyses in our vegetative test plots. The percent native coverage metric allows for a measurement of how the seed mix established and how the seed mix persists over time. The percent native coverage under and in between the solar photovoltaic (PV) arrays rose from 10% after one year of planting to 58% after three years across all sites, while the native coverage of the full sun control area rose from 9.6% to 70% under the same period, showing that native prairie and pollinator plants successfully established under the array, although to a lesser extent than in full sun conditions. Percent native coverage under the PV arrays rose 5- to 8-fold for each of the three sites from over the course of the study, while the coverage of weeds decreased for all three sites over the same period. Percent native coverage varied by seed mix over the project years, but every seed mix experienced a higher percent native coverage year after year under the PV arrays. Our results did not indicate a difference in establishment across placement within the array; the center, west, and east portions of the areas in between panels had similar establishment rates at two out of three sites, indicating that the same seed mix can be applied throughout the array. Out of 101 plant species seeded, we observed the establishment of 68 species in our vegetative test plots, and we detailed the top 20 observed species to inform future seed mix development. Based on these findings, native pollinator vegetation can establish over time at solar arrays, and it can be suitable for creating habitat at utility-scale solar sites.

Pollinator response to livestock grazing: implications for rangeland conservation in sagebrush ecosystems.

World food supplies rely on pollination, making this plant-animal relationship a highly valued ecosystem service. Bees pollinate flowering plants in rangelands that constitute up to half of global terrestrial vegetation. Livestock grazing is the most widespread rangeland use and can affect insect pollinators through herbivory. We examined management effects on bee abundance and other insect pollinators on grazed and idle sagebrush rangelands in central Montana, USA. From 2016 to 2018, we sampled pollinators on lands enrolled in rest-rotation grazing, unenrolled grazing lands, and geographically separate idle lands without grazing for over a decade. Bare ground covered twice as much area (15% vs. 7) with half the litter (12% vs. 24) on grazed than idle regardless of enrollment. Bee pollinators were 2-3 times more prevalent in grazed than idle in 2016-2017. In 2018, bees were similar among grazed and idled during an unseasonably wet and cool summer that depressed pollinator catches; captures of secondary pollinators was similar among treatments 2 of 3 study years. Ground-nesting bees (94.6% of total bee abundance) were driven by periodic grazing that maintained bare ground and kept litter accumulations in check. In contrast, idle provided fewer nesting opportunities for bees that were mostly solitary, ground-nesting genera requiring unvegetated spaces for reproduction. Managed lands supported higher bee abundance that evolved with bison grazing on the eastern edge of the sagebrush ecosystem. Our findings suggest that periodic disturbance may enhance pollinator habitat, and that rangelands may benefit from periodic grazing by livestock.

Modern approaches to the use of Berberis Thunbergii cultivars for sustainable landscape design

Purpose. For the purposes of sustainable landscape design of the urban space, to substantiate new modern nature-oriented solutions for the use of dwarf cultivars of the Berberis Thunberg species. Methods. Visual assessment, computer modeling and visualization. Results. One of the aspects of realizing the goals of sustainable development, namely Sustainable development of cities and communities, is the rationalization of living space in cities. An integral part of this process is the aesthetic arrangement of territories, which ensures sustainable landscape design. The design of flower arrangements, flower beds can and should change, be updated, absorb new things. One of the ways of realizing such a context when creating permanent flower beds is the use of metal frame structures, which solve the task of creating a contrast with the colors of decorative plant compositions. The choice of the color of the metal frame should be subject to the thematic and landscape context. In order to give graphicness to decorative plant compositions from cultivars of Berberis thunbergii species, the expediency of horizontal contouring of the plant ornament with metal structures with a width of contour lines of 3–5% of the linear dimensions of the structure is shown. Modeling of structures was carried out using the program Realtime Landscaping Architect 2023.02, Trial Free Version. The use of the color solution, shape, texture of the modeled structures, the use of contour lighting of the decorative-but-foliage installation is substantiated. Cultivars of Berberis Thunberg are given, which are appropriate for use, the life span of which can reach 50 years under the conditions of performing the necessary minimum care. Conclusions. The creation of permanent, aesthetically expressive flower beds and flower beds involves not only the use of environmentally friendly materials, but also the choice of local or adaptive decorative cultivars that provide all-season decorativeness, the absence of the need for annual renewal of plant material, artificial watering, and the creation of a habitat for pollinators and birds The use of cultivars of the Berberis Thunberg species contributes to the creation of stable flower beds that are able to preserve their decorative characteristics for a long time. The most harmoniously proposed compositions will be revealed in the presence of dynamic visual points, a deep perspective and a panoramic view.

Host plants and landscape predict use of roadside habitat by breeding monarchs

Abstract Vegetation along roadside edges, while posing some risks, can also provide breeding habitat for monarch butterflies. We investigated how landscape and site‐specific factors affect the quality of roadsides as monarch breeding habitat. We surveyed more than 250 sites along roadsides throughout Minnesota for milkweeds, floral resources and monarch eggs and larvae. We found that milkweed distribution was affected by adjacent land use and geography, with milkweeds more likely to be present in roadsides adjacent to crop and grassland and the south and west of the state. The presence and density of monarch eggs and larvae were primarily driven by milkweed density, with the likelihood of monarch presence at each site increasing with milkweed density. The density of monarchs per plant increased in sites with lower densities of milkweed, suggesting that monarch eggs are concentrated more densely on fewer plants where milkweed is scarce and spread more thinly across plants where milkweed is common. Monarch density per milkweed increased as sites were farther from core grasslands, to the south, and on narrower roadsides, also suggesting use may be higher in areas with a scarcity of habitat. The density of monarch eggs and larvae was higher in mowed than unmowed milkweed. Our study suggests that roadside habitats effectively provide breeding locations for monarchs, regardless of adjacent land use type and even when distant to high‐quality natural areas. Our findings assist conservation practitioners in planning and managing roadside habitats for monarchs and other pollinators.

Interviews with farmers from the US corn belt highlight opportunity for improved decision support systems and continued structural barriers to farmland diversification

Diversifying high-input, monocropped landscapes like the US Corn Belt would provide both economic and ecosystem service benefits to the agricultural landscape. Decision support systems (DSS) and digital agriculture could help farmers decide if diversification is suitable for their operation. However, adoption of DSS by farmers remains low, likely due to lack of farmer engagement before and during the DSS development process. This study aimed to better understand the tasks, tools, and people involved in implementing farmland diversification with the goal to inform design of agricultural DSS. Semi-structured interviews were conducted with 11 farmers who had diversified their corn/soybean cropland with government-supported conservation programs (e.g., CRP, wetlands) and alternative crops (e.g., small grains, pasture) in the past four years. Interview data was transcribed and then analyzed using affinity diagramming. Results show farmers needed DSS to layer multiple sources of data and observations over several years to identify field productivity trends and drivers; spatial orientation of practices to fit management and field constraints; matching operation goals to alternative practices; financial planning and market exploration; and information on promising emerging practices like subsidized pollinator habitat. However, the interviews also highlighted structural barriers to diversification that DSS cannot or can only partially address. These included social pressures; market access; crop insurance policy; and quality of relationships with governmental agencies. Results indicate better DSS design can empower individual farmers to diversify cropland, but structural interventions will be needed to successfully diversify the agricultural landscape and support economic and ecosystem health.

Pollinator planting establishment and bee visitation are influenced by seeding rate and post‐seeding management

Perennial wildflower plantings are commonly used to support pollinators and other beneficial insects, but their establishment can be costly, and few studies have directly compared the effectiveness of different management strategies for wildflower establishment. To determine the relative importance of pre‐seeding weed control, seed density, and post‐seeding management on seed mix establishment, we developed a multifactorial field experiment in a grass‐dominated weed community. Pre‐seeding management treatments (mowing, herbicide, or soybean cover crops) did not affect the stem density of sown plants, or the percent of ground covered by sown plants. However, the percent of ground covered by weeds was significantly influenced by pre‐seeding treatments, with infrequent mowing resulting in significantly less weedy ground cover than the herbicide or soybean pre‐seeding treatments. Plots with a higher seeding rate had a significantly greater density of sown wildflower species and a higher percent cover of these species after 3 years. Plots that received no post‐seeding management had higher stem density, a greater percent ground cover of sown forbs, and higher species richness compared to those that were intensively managed (mow or mow + herbicide). The total number of bee visits (honey bees, bumble bees, and other wild bees) increased with higher forb species richness, higher ground cover of sown forbs, and higher sown species richness. Doubling the density of seeds resulted in a 24.3% increase in the number of wild bees observed. When establishing wildflower habitat for pollinators, investment in ground preparation and seeding density has the greatest impact on sown species establishment.

Milkweed and floral resource availability for monarch butterflies (Danaus plexippus) in the United States

The global decline of pollinators, particularly insects, underscores the importance of enhanced monitoring of their populations and habitats. However, monitoring some pollinator habitat is challenging due to widespread species distributions and shifts in habitat requirements through seasons and life stages. The monarch butterfly (Danaus plexippus), a migratory insect pollinator that breeds widely throughout North America, presents a unique case study for testing a sampling framework to overcome these challenges. Monarchs exhibit discrete resource needs across life stages (e.g., larval requirement for milkweed, adult requirement for floral nectar), utilizing many land use types across their extensive geographic range during breeding and migration seasons. The Integrated Monarch Monitoring Program (IMMP) uses a standardized protocol with a generalized random tessellation stratified (GRTS) sampling design to gather spatially balanced and ecologically representative information on monarch habitats within the United States. The IMMP is applicable to various land use types and habitats used by breeding monarchs and may be extended to sites outside of the GRTS design to collect data on non-random sites of interest, such as legacy or conservation sites. Additionally, the IMMP’s modular design and publicly available training allows for broad participation, including involvement from community scientists. Here, we summarize habitat metrics (milkweed and floral resources) across 1,233 sites covering much of the monarch’s breeding range. We examine variation in milkweed density and floral resource availability on probabilistic (random) and non-probabilistic (convenience) samples and among land use types (site types). Additionally, we assess resource availability within core geographies for monarch breeding and migration, specifically within the U.S. Fish and Wildlife Service’s Monarch Conservation Units (western, northern, and southern United States). Milkweed density, floral frequency, and floral richness were higher on non-random sites and in the North region. Among site types, milkweed density was highest on Rights-of-Way and Unclassified Grassland, while floral frequency was lowest on Rights-of-Way. The IMMP represents the first field-based habitat monitoring program of this scale for monarchs, yielding a robust dataset on monarchs and their habitats across their breeding range and offering a framework for surveying the habitat of insect species with diverse habitat requirements or widespread distributions.

Wildflowers and compost amendment can improve infiltration in soils impacted by construction

AbstractVegetation is an important component of stormwater control measures, as vegetation can reduce erosion and runoff. While grass is typically used in stormwater control measures, wildflowers can be planted to reduce maintenance and improve pollinator habitat. Previous studies have established that tillage followed by establishment of a vigorous vegetation stand can increase infiltration relative to compacted soils. Compost can also improve soil physical properties and fertility. The goal of this study was to evaluate potential improvements in infiltration using tillage together with compost and either grass or wildflowers. Wildflowers or grass were planted on tilled soil with or without compost at three sites in North Carolina. Bulk density, infiltration rate, root mass density, and penetration resistance were measured every 6 months over a 30‐month period. A subset of plots received wheel traffic from a mower. Compost application reduced bulk density compared to tillage alone. Compost improved infiltration at two sites (46%–50%). Wildflowers improved infiltration at all sites (30%–43%) compared to grass. Few differences were observed in root mass and penetration resistance. Mower traffic reduced soil improvements more in grassed plots than wildflower plots due to higher mowing frequency. Results suggest compost and/or wildflowers together with tillage (at establishment) provide viable options to improve soil conditions and infiltration rate in construction impacted soils.