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Bee diversity and abundance on flowers of industrial hemp (Cannabis sativa L.) 2019. Biomass and Bioenergy. 122, 331-335.
Abstract
Industrial hemp, (Cannabis sativa L.), one of the earliest crops spun for fiber, is now used for a variety of commercial products including paper, textiles, clothing, biodegradable plastics, biofuel, food, animal feed etc., all of which are derived from hemp fiber or seeds. Being wind pollinated, dioecious and staminate hemp plants produce large amounts of pollen that are attractive to bees. Hemp flowering in northern Colorado, where this study was conducted, occurs between the end of July and the end of September. This time period coincides with a dearth of pollinator-friendly crop plants in the region, making hemp flowers a potentially valuable source of pollen for foraging bees. Here we present the diversity and abundance of bees collected in the fields of flowering hemp. A total of 23 different genera of bees were collected of which the European honeybee, Apis mellifera at 38% of the total abundance was the most dominant followed by Melissodes bimaculata at 25% and Peponapis pruinosa at 16%. These three genera made up nearly 80% of the total abundance. While hemp does not produce any nectar, the pollen rich nature of the flowers can make hemp an ecologically valuable crop. As cultivation of hemp continues to expand, we expect insect pests on hemp to also become prevalent. Our results documenting bee diversity in flowering hemp provides the impetus for the development of integrated pest management plans that protect pollinators while controlling pests.
... The flowers produce pollen but not nectar. Several different bee groups have been reported on industrial hemp flowers [7], suggesting that this may be a potential source of pollen for foraging bees. Pollinators, including bees, rely on floral resources (nectar and pollen) for reproduction, development, and survival [8][9][10]. ...
... The community of bees documented here was similar to that of previous work with the same bee types (honey bees, bumble bees, and sweat bees) [47,48]. However, another study [7] indicated additional bee species, including the longhorn bee, miner bee, and leafcutter bee. Sweat bees were the most abundant bees in our study, accounting for 84.7% of the bee community on all four hemp varieties (Figure 4). ...
... Sweat bees were the most abundant bees in our study, accounting for 84.7% of the bee community on all four hemp varieties (Figure 4). In other studies, the honey bee was the most abundant, comprising nearly 60% [7] and 30% [48] of the bee community on industrial hemp. Several factors could have played a role in influencing the abundance and type of bee recorded. ...
Apart from its economic value, industrial hemp (Cannabis sativa L.) is a prolific pollen producer, serving as a food source for bees. However, little is known regarding the extent to which varietal differences in hemp pollen chemistry influences bee preference. Here, we report the chemical profile of pollen from four hemp varieties (Canda, CFX-2, Henola, and Joey) and bee abundance and diversity, using direct visual counts and pan traps. The number and type of bees on each variety was recorded and the chemical composition (proximate analysis and mineral, amino, and fatty acid profiles) of pollen from each hemp variety was determined. During the entire sampling period, three bee types (bumble bees, honey bees, and sweat bees) were recorded, with a combined total of 1826. Among these, sweat bees and bumble bees were the most prevalent and were highest on the Joey variety. The four varieties expressed protein content ranging from 6.05% to 6.89% and the highest in Henola. Seventeen amino acids were expressed in all varieties, with leucine recording the highest content ranging from 4.00 mg/g in Canda to 4.54 mg/g in Henola. In general, Henola expressed high protein, amino acid, and saturated and monosaturated fatty acid contents and recorded significantly fewer bees compared with Joey, which had a low content of these components and a high content of polyunsaturated fatty acids. Our findings suggest that, while industrial hemp offers abundant and accessible pollen that would promote bee health and sustainability of their ecosystem services, the nutritional quality may not be adequate for bee growth and development as an exclusive pollen source.
... Simpson's Index ( = 1/ ∑ 2 ) =1 [19]. Shannon-Weiner index combines evenness and richness into a single measure and assumes that all genera are represented in a sample while Simpson's index gives more weight to common genera and assumes that the few rare ones with only a few representatives will not affect the diversity values [19]. ...
... Simpson's Index ( = 1/ ∑ 2 ) =1 [19]. Shannon-Weiner index combines evenness and richness into a single measure and assumes that all genera are represented in a sample while Simpson's index gives more weight to common genera and assumes that the few rare ones with only a few representatives will not affect the diversity values [19]. ...
The contribution of insect pollinators to the ecology and production of food crops is threatened by excessive use of pesticides. Pesticides have an impact on reducing the presence of pollinators in agricultural land. The diversity of pollinators depends on food availability and habitat quality. This research emphasizes the diversity of insect pollinators by the application of pesticides in chili plantations in Muaro Jambi, Sumatra. Insect observations were conducted on April-May 2018 using the scan sampling method. Specimen collection is carried out from 08.00-16.00. Data analysis used Shannon-wiener diversity index (H’), Simpson’s index (D), and Pielou evenness index (E). The results of the study were 498 collected individuals consisting of 9 species. Apis melífera, Apis cerana, and Eurema hecabe are the most dominant insect pollinators. Whereas Apis mellifera showed two peaks of flower visitation (an intense first one between 08.00 until 11.00 a.m. and a second less intense one after 14.00 p.m.). Pollinator insect diversity index in the medium category. Our observations also show that the application of pesticides, anthesis and dehiscence to flowers as well as the activity of pollinating insects which together cause low diversity index values.
... Bee wax is used in the medical field to control bleeding during surgery from the bone surface, also used as a dental tooth filling. It uses for oil spill control, and to absorb oil or petroleum-based pollutants from water to create Petroleum Remediation Products (13). ...
... Cannabis sativa L., or hemp, is an annual herbaceous plant in the Cannabaceae family [22]. Environmental elements, such as climate and geography, play a pivotal role in shaping the composition of hemp seeds [23]. ...
Purpose
This study aimed to investigate the effects of high-intensity interval training (HIIT) alone or in combination with hemp seed on total testosterone (TT) levels, sex hormone-binding globulin (SHBG), body composition, oxidative stress, and antioxidant capacity in sedentary young males.
Methods
Randomly, 48 young sedentary males were assigned among four groups (each comprising 12 individuals) as follows: HIIT + hemp seed (HH), HIIT + placebo (AT), hemp seed only (HS), and control. For eight weeks, exercise groups had HIIT three times per week. Hemp seed groups received 2 g of powder daily. The plasma levels of TT, SHBG, catalase (CAT), superoxide dismutase (SOD), malondialdehyde (MDA), and also body mass index (BMI), body fat percentage (BF%), and muscle mass percentage (MM%) were measured. The analysis was based on the intention-to-treat (ITT) and per-protocol (PP).
Results
Based on ITT, BMI and BF% decreased, and MM% increased significantly post-intervention in HIIT groups (p < 0.05). TT increased significantly in the HH [mean difference 0.45, 95% CI 0.1 to 0.7, p = 0.005] and AT [mean difference 0.37, 95% CI 0.1 to 0.7, p = 0.01]. The whole hemp seed components showed a significant antioxidant potential. However, none of the SOD, CAT, and MDA indices showed significant changes post-interventions (p ≥ 0.05).
Conclusion
Finally, HIIT and hemp seed intake showed no significant effects on the antioxidant defense system. However, regular HIIT significantly increased TT levels and improved body composition in sedentary young males.
Trial registration
Iranian Registry of Clinical Trials (registration code: IRCT20140907019082N10).
... Furthermore, the Cannabis plant relies solely on wind for pollination and exhibits a notable capacity for generating a substantial quantity of pollen. This characteristic contributes to the establishment of an ecosystem that is very appealing to various bee species, which plays a vital role in promoting sustainable agricultural practices (O'Brien & Arathi, 2019). Although the Cannabis plant does not generate nectar, its blooms, which are abundant in pollen, contribute to the ecological significance of the Cannabis plant as a crop. ...
The Cannabis plant (Cannabis sativa L.), also known as hemp, is a sustainable and multipurpose plant that may be used for a wide range of purposes, from the fiber in its stalks to the food in its seeds to the oil in its flowers and seeds. Since the Cannabis plant has been recognized to be an outstanding carbon trap and environmentally friendly biofuel that supports all three aspects of sustainability-the economy, the environment, and society-it may provide a solution to the climate change dilemma. The cultivation of the Cannabis plant has been practiced as a dietary staple in numerous places across the globe for an extended period. However, its production has been prohibited in several countries mostly owing to its relationship with illicit drug consumption. The illegality of the plant has impeded research efforts for an extended period of time on a global scale. As a result, people's ability to assess the whole range of beneficial effects and dangers shrank. However, the global trend toward Cannabis legalization and decriminalization has accelerated in recent years. This has stimulated more investigation into the botanical, ecological, and practical aspects of the plant. This study reviewed the available literature to understand more about the Cannabis plant's global sustainability. The results demonstrated the potential of Cannabis plants to affect product sustainability and the use of hemp as a renewable raw material. Furthermore, this review outlines the connections between the Cannabis plant and the Sustainable Development Goals (SDGs) of the United Nations. This research fills a gap in our understanding of the Cannabis plant's sustainability as a highly promising multipurpose crop for the future.
... Industrial hemp is used for a variety of commercial products, including paper, textiles, clothing, biodegradable plastics, biofuel, food, and animal feed. Wind-pollinated, dioecious, and hardy cannabis plants produce large amounts of pollen attractive to bees [2]. Hemp flowers release an abundance of pollen during a period of native and agricultural floral dearth late in the summer [3,4] therefore, hemp pollen The antioxidant and antimicrobial effects of propolis make it attractive to use in the food industry. ...
In this study, both chemical characterization and biological activities of propolis samples obtained from Cannabis sativa L. (cannabis, hemp, marijuana) isolated colonies (research group) and obtained from colonies at a distance where the bee cannot fly to the isolation area (control group) were determined. Palynological analyses of propolis samples obtained from the research and control group colonies were made and the botanical origin of the cannabis plant and other plants in the research area and the plants in the control group were determined. Bioactive component analysis of propolis extracts was determined by the GC–MS technique. The inhibition effect of propolis samples on some enzymes of medical importance and their antimicrobial effects against many pathogenic microorganisms were also investigated. Palynological analyses showed that honey bees prefer cannabis plants (11.11%) when collecting propolis, and the dry matter percentage (94.6 ± 1.8%), balsam (46.2 ± 5.2%), and wax content (4.8 ± 0.5%), total phenolic (26.44 ± 1.08 mg GAE/mL) and total flavonoid (2.03 ± 0.11 mg QE/mL) content and antioxidant capacity (88.16 ± 2.27 μM FeSO4·7H2O/mL⁻¹) of the research group propolis samples containing hemp were found to be higher than the control group. Also, it was determined that the research group propolis sample contains cannabinoid derivatives (cannabidivarinic acid, 0.29%; delta (1)-tetrahydrocannabinolic acid, 0.59%; cannabidiolic acid, 0.48%), which are active compounds of the cannabis plant. Also, a high inhibition effect was detected on some enzymes of medical importance in propolis samples obtained from cannabis group colonies. In addition, the research group propolis samples also showed a high antimicrobial effect against many pathogenic microorganisms.
... Subsessile pairs are pairs of flowers that have very small stalks (Barcaccia et al. 2020). These greenish white flowers are inconspicuous and composed of inflorescences and trichomes, with 5-7 flowers per inflorescence (De Meijer et al. 2003, Rana and Choudhary 2010, Davidson et al. 2018, Brien and Arathi 2019. Inflorescences are clusters of flowers arranged on a joint stem. ...
Cannabis sativa L. is a crop plant that is native to Asia. It is a primarily dioecious annual agriculturally used for its seed, fiber, and flowers. After recent legislative action legalized hemp nationally for research and cultivation in the US, distinct classifications had to be made. Cannabis sativa L. cultivars are presently separated into two major categories by the FDA: medical marihuana and hemp. Within the hemp classification, there is CBD-type hemp and industrial hemp. These classifications are based on Cannabis sativa L.’s chemical composition, which varies throughout the plant’s tissue. The desired cannabinoid chemicals for CBD-type hemp and medical Cannabis (high THC) are found in high concentrations in the female flowers. To differentiate CBD-type hemp from medical marihuana, the USDA’s current regulations limit tetrahydrocannabinol (THC) concentration to no more than 0.3% total. Genetic research on the plant has been, until recently, limited to legal applications of differentiating industrial hemp from medical marihuana. This study has been completed to ascertain Cannabis sativa L.’s current chemical composition and genetic diversity among Maryland growers. Hemp growers located across Maryland provided the field sites and samples. Chemical composition was determined from an analysis of flowers through a partnership with a Morgan State University chemistry lab. The determination of genetic diversity was completed on hemp leaves through the analysis of 12 standard and novel microsatellites. Cannabis sativa L. samples were taken from eight field sites across twenty eight distinct cultivars. Cultivars #5 and Cherry had the highest CBDA content among the strains studied. Microsatellite analysis determined that the most genetically variable cultivars were A-B1 and #5. With this research, CBDA type hemp growers in Maryland will be able to determine some strains which have high concentrations of their desired cannabinoids and which cultivars are more genetically variable.
... Bees have been observed in hemp, but these reports have been from pollen producing fiber or grain varieties of the crop (O'Brien and Arathi, 2019;Flicker et al., 2020). The floral/ cannabinoid varieties sampled in this study do not produce pollen. ...
Hemp is a newly (re)introduced crop to United States and California agriculture. A study was initiated in the summer of 2021 to survey the arthropods present in hemp in two regions of California: Fresno County in the Central Valley and Ventura County along the Central Coast. Eight hemp plots were sampled every two weeks from August to mid-October using a combination of D-vac samples, leaf collections, and visual observations. All samples were processed and ultimately recorded as the total number of specimens collected per morphospecies across all sampling dates, further broken down to express the number of specimens collected from the Central Valley and the Central Coast. D-vac sampling was the most reliable method for specimen collection and led to the recovery of arthropods from 11 orders, 69 families, and 157 morphospecies. Approximately 13,000 specimens were collected and processed, half of which were whiteflies (Hemiptera: Aleyrodidae). Of the specimens recovered, Hemiptera was the most representative order (with and without whiteflies), followed by Thysanoptera and then Hymenoptera. The most frequently collected specimen was Engytatus modestus (Hemiptera: Miridae). Very few pest species were recovered, cannabis aphid (Phorodon cannabis) being the only one that was observed in any noticeable density. Many generalist predators and parasitoid wasps were also collected. Findings from this survey provide baseline information on the arthropod species present in California hemp. This survey will be repeated and expanded in future growing seasons.
... The crop is used to produce a variety of commercial products, such as paper, textiles, biodegradable plastics, functional foods, cosmetics and nutraceuticals. 1 Hempseed is rich in oil, minerals and proteins, and can be used as food or food ingredient. 2 The high demand from markets and consumers to avail sustainable, environmentally friendly and more diverse sources of proteins has transformed plant-based proteins into an important field of research. In hemp, the cake recovered after oil extraction is a high-value by-product, with a considerable amount of proteins. ...
BACKGROUND
Hempseed meal, a by‐product of the hempseed oil processing stream, is a potential alternative source for food proteins. Efficient extraction of proteins from hempseed meal is challenging owing to differences in the structure and solubility of various protein fractions present in the seed. In the present study, protein was extracted from hempseed meal using four different solvents, including aqueous NaOH, KOH, NaHCO3 and NaCl, at four different concentrations with the aim of improving the recovery of protein fractions rich in essential amino acids.
RESULTS
Extraction using alkaline solvents provided superior protein recovery (60–78%) compared with NaCl solution and control extractions (20–48% and 21%, respectively). The concentration of alkali or salt (0.25–1 mol L⁻¹) had a minor but significant impact on the yield. Amino acid composition analysis revealed that hempseed meal contains 24% (54.5 ± 0.19 mg g⁻¹) essential amino acids of total amino acids, and extraction with NaOH, KOH, NaHCO3 or NaCl did not improve the selective extraction of essential amino acids compared to control experiments. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS‐PAGE) analysis allowed the identification of edestin and albumin in the extracts obtained with NaHCO3 and NaCl solvents, with results further showing that the type of extraction solvent influences protein extraction selectivity.
CONCLUSION
Although alkali solvents provide superior extraction yields, extraction with water resulted in extracts containing the highest proportion of proteins bearing essential amino acids. According to the results of SDS‐PAGE, extraction using alkali solvents induced protein crosslinking. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
... While most ecological studies focus on systems that are widespread or have long been prominent, studying novel systems allows researchers and land managers to glean an early understanding of potential effects. For example, despite initial trepidation around the ecological effects of Cannabis sativa (hemp) production, studies have shown this crop can serve as important habitat to pollinators (O'Brien and Arathi, 2019) and that secondary compounds in this plant can repel root-knot nematodes, a major agricultural pest (Kayani et al., 2012). On the other hand, the relatively new and growing use of tarps on agricultural fields has shown preliminary negative effects on soil biodiversity and respiration, possibly due to heating soils to inhospitable levels (Birthisel et al., 2019). ...
New land uses can drive complex changes to local biodiversity. In the Northeastern U.S., cultivated milkweed has arisen as a new crop with potentially promising outcomes for monarch butterflies, but has unknown effects on surface-active and soil-dwelling arthropods. We assessed differences in arthropod communities among nearby sites containing milkweed and three common regional land uses: conventional corn, conventional hay, and forest, representing a spectrum of high to low land use intensity. In each land use, we sampled surface-active and soil-dwelling arthropods, and we classified organisms at the taxonomic order level for all collected arthropods and at the taxonomic genus level for surface-active beetles. To address differences in functional traits between sites, we measured organisms’ body sizes and calculated average body mass, total biomass, and abundance of arthropods in small, medium, and large size classes. In almost all analyses, taxonomic diversity values were significantly higher in the milkweed site than in corn and similar between the milkweed and hay sites. Milkweed had significantly higher diversity of surface-active arthropods than forest (for both orders and beetle genera), but did not have higher diversity of soil-dwelling arthropods, indicating possible different mechanisms driving aboveground versus belowground trends. Community composition differed significantly among land uses (demonstrated in NMDS ordination plots), with milkweed most similar to hay. Body size analyses demonstrated high total biomass and generally higher abundance of larger individuals in milkweed than in other land uses, with the exception of corn, which was dominated by large carabid beetles. We discuss the implications of our findings to land use properties and ecological function. Our case study indicates promising benefits of milkweed cultivation for soil biodiversity and soil health, with more research needed to validate and build from our results.
... Although grazing is known to influence insect abundance and diversity, Sjödin et al. (2008), in their study in central Sweden, showed that diversity and abundance of bees and butterflies were not affected by grazing intensity to the same extent as it affected hoverflies (Syrphidae) and beetles. Increase in abundance of bees under high levels of grazing has been previously reported (Vulliamy et al. 2006) where it is also suggested that the increased bee abundances at high grazing levels may not be due to changes in floral resources but could be a result of a few genera that could drive these abundance values (Herbertsson et al. 2016, O'Brien and Arathi 2018, O'Brien and Arathi 2019. This can explain the high abundance of Lasioglossum in our study and being semi-social, Lasioglossum may also have a competitive advantage over other solitary bee genera (Michener 1974, Cane 2015, Wilson and Carril 2015. ...
Recent reports indicate that global insect populations are drastically declining, and amongst insects, bees have attracted significant attention. Decades of research on causal factors for bee population declines, indicate that extensive loss of natural habitats resulting from urbanization and agricultural intensification, has led to a dearth of critical nesting and forage resources essential for the sustenance of bees. To address these concerns and to meet the growing need for food production, simple but effective farm management practices such as restoring habitat diversity through planting pollinator habitats along field margins and underutilized areas, revegetating retired farmland with wildflowers and including pollinator-friendly forbs in cover crop mixes, have been recommended. Earlier studies have provided evidence that planting pollinator habitats along field margins and revegetating retired farmland are indeed viable ways to sustain bee pollinators. Here we report results of a case study exploring the benefits of cover cropping with a pollinator-friendly forb mix. Our results indicate that cover cropping to support pollinators can be effective, particularly when cover crops are retained until the flowering stage and that grazing of cover crops could extend support to those genera of bees that prefer grazed areas. Although the reports on global insect declines are dire, our studies show that pollinator-friendly farm management practices can offset the declines and play a significant role in supporting pollinator populations. Regular assessment of the efficacy of these practices will enable us to target efforts towards better implementation of habitat conservation programs.
... Eurasia is considered the origin of hemp. Cannabis has been cultivated for food, fibre and medicine for more than six millennia (Salentijn et al., 2015;Kerckhoffs et al., 2015;O'Brien & Arathi, 2019). Cannabis is classified into two distinct groupsmarijuana and hemp based on the uses. ...
Hempseed products are projected to receive great potentials due to the rapid growth in the US market. Industrial hemp has been an important crop for food, fibre and medicine applications. Hempseed products can be used as nutraceutical supplements and functional foods for human and can be applied for animal feed. This review provides a comprehensive summary of nutritional quality and health benefits of hempseed which is attributed to high levels of essential fatty acids and other PUFAs in the oil, with a rich source of essential amino acids in highly digestible protein. This review examines the impact of extraction methods on oil yield and bioactive compounds, nutrition value, and food application of hemp protein‐extracted products, including meal, protein isolate and protein concentrate. Recent research related to the understanding chemical composition, nutritional value, health benefits, processing impact, functional properties of hempseed products, and their application for food and feed is presented.
Peach ( Prunus persica [L.] Batsch) is an important speciality fruit crop in the United States. Peach is self‐compatible, but bee pollination enhances fruit sets and diverse populations improve pollination efficiency. However, the bee diversity and abundance in peach orchards in South Carolina are unknown. To understand this, we sampled bees during peach tree bloom at two locations in South Carolina—the Clemson University Musser Fruit Research Center (MFRC) and a peach farm in Ridge Spring, South Carolina. Overall, a total of 651 bees were collected from peach orchards, of which Bombus (37%) and Apis (32%) were the most dominant genera, followed by Eucera (14%), Andrena (8%) and Habropoda (5%). Diversity indices indicate higher species richness and diversity at the Ridge Spring farm than at MFRC. Dominant species at the MFRC were Apis mellifera (36.77%), Bombus bimaculatus ( 29.1%), B. griseocolis (12%) and Eucera hamata (8%). In contrast, the Ridge Spring farm was dominated by A. mellifera (24.17%), Habropoda laboriosa (12%), Andrena barbara (12%), E. atriventris (11.72%) and B. bimaculatus (11.35%). In comparing the effectiveness of sampling methods, blue vane traps (BVTs) captured more bees than aerial sweep netting. Furthermore, BVTs predominantly captured larger‐sized bees, while smaller‐sized bees were more frequently collected using sweep netting. Throughout peach bloom, differences in bee abundance were observed over time as well. Our study sheds light on the bee diversity and abundance in South Carolina peach orchards, revealing variations between locations. This knowledge of bee diversity and abundance will provide baseline information on bee communities in peach orchards and will help develop suitable pollinator conservation programs.
Hempseed meal, a co-product of hemp oil extraction, contains about 40 % proteins, which has recently become abundant because of the large demands of hemp oil related products. It has been an acute issue for hemp industries to utilize the hempseed meal for value-added products. On the other hand, wood industries are constantly seeking plant protein alternatives not only to secure plant protein sources but also to improve wet adhesion properties. In this study, native hempseed protein was identified to have great potential for wood adhesive applications. Hemp proteins were extracted from two types of hempseed meals: Hlesia and commercial hempseed meals. Then the extracted hemp proteins with and without modification were used to prepare wood adhesives. Glutaraldehyde, previously identified as a toxic but effective crosslinker for soybean protein adhesives, was used as the crosslinking reagent for hemp protein in this study. Results showed that the wet adhesion strength of hemp proteins without modification was similar or superior compared to published data such as modified soy protein-based adhesives. Glutaraldehyde crosslinker only improved wet adhesion of commercial hemp protein at low press temperature such as 150 °C and 150–170 °C for Hlesia hemp protein. At press temperature 170–190 °C, wet adhesion of commercial hemp protein was not affected by glutaraldehyde crosslinker, while for Hlesia hemp protein, wet adhesion was not affected by glutaraldehyde crosslinker at 190 °C. The highly hydrophobic amino acid contents of hempseed proteins were identified to attribute to the unique wet adhesion performance for low water solubility and water resistance, which is essential for plant protein-based adhesive application. This is the first time to demonstrate that native hemp proteins could be a feasible and valuable alternative source of plant protein-based adhesives.
Cultural crop-production practices are not only engineered to minimize pest incidence but also improve resource use efficiency and increase the diversity of habitat for beneficial insects that provide pollination services. With the increasing cultivation of industrial hemp and the benefits associated with the cultivation of multiple crops, its integration into a polyculture cropping system remains to be evaluated. We intercropped two pollinator-attractive crops, hemp and cowpea, with squash, a pollinator-dependent crop, to evaluate the impact of pollinator abundance and diversity on crop yield. Intercropping significantly increased the overall abundance of pollinators with 79.1% recorded from the intercropping systems compared to 21.9% in the monocropping systems. Sweat bees and bumble bees were the most abundant bees, and Squash+Cowpea was the most diverse cropping system. Intercropping significantly increased the yield of squash with higher squash yield (155%) in Hemp+Squash and (161%) in Squash+Cowpea than in squash monocrop. Also, intercropping resulted in higher hemp yield (64%) in Hemp+Cowpea and (165%) in Hemp+Squash compared to hemp monocrop. This study demonstrated that agricultural systems such as intercropping that are designed to attract pollinators are much more productive by not only improving crop yield but also growers’ returns on investments.
Se realizó una revisión bibliográfica en alrededor de 20 artículos científicos entre el año 1999 y el año 2023 sobre el Cáñamo y la Biodiversidad. Como resultado de esta revisión, se encuentra que el Cáñamo es un enriquecimiento para la agrobiodiversidad, mejora la biodiversidad, tiene un efecto positivo en la biodiversidad, tiene impacto beneficioso sobre la pérdida de biodiversidad, contribuye a una mayor biodiversidad, puede respaldar la biodiversidad, ser beneficioso para la biodiversidad y puede ampliar la biodiversidad, es decir hay un gran potencial por desarrollar, de la mano de nuevas investigaciones que hagan realidad este potencial, sobre todo en Latinoamérica que a su vez es la potencia de la Biodiversidad.
Intensive surveys conducted in 0-3 km radius of the experimental apiary during the dearth periods (June-October) in 2017 and 2018 unraveled 71 plant species belonging to 31 families as crucial flora for Apis mellifera L. foragers at Kaul, Kaithal, Haryana. Bee flora comprised of 23 weeds (32.4%), 16 ornamentals (22.5%), 12 plantation crops/trees (16.9%), 7 vegetable crops (9.9%), 5 fruit crops (7.1%), 3 forage crops (4.2%), 2 each oilseed and cereal crops (2.8% each) and 1 leguminous pulse crop (1.4%). Among the families, Fabaceae consisted of maximum floral resources (10, 14.1%) followed by Asteraceae (7, 9.9%) and Cucurbitaceae (5, 7.0%). Bee floral calendar was also prepared along with the description of reward potential to A. mellifera foragers in terms of pollen and nectar.
Industrial hemp (Cannabis sativa L.) has considerable potential as a sustainable crop for numerous existing industrial and consumer products, with many more likely still to be realized. Much early excitement about this ancient crop arose from its assumed capacity to supply renewable feedstocks (e.g., fibers, grain, biomolecules) for numerous uses, both with little environmental “footprint” and the ability to be recycled or upcycled. Although many tout hemp as the solution for all things, such enthusiasm should be tempered by issues of historical precedent and of scale. First, the lack of research investment during the decades-long restriction in the West ensures that time will be needed to develop sustainable hemp production systems. Even as these systems are developed, there are questions about the capacity to grow sufficient amounts of hemp to meet the needs for an array—and large volume—of products. Still, there is room for guarded optimism that as the crop comes “on line,” it will receive the research needed to make the plant a viable resource for farmers and society. This review explores hemp sustainability issues in agronomic and systems contexts and touches on some of the attendant challenges to scale-up.
Although hemp cultivation is increasingly perceived as a promising option in terms of crop diversification, especially in semi-arid conditions such as in the Mediterranean region, its adoption remains limited thus constraining the development of hemp value chains at a larger scale. Our objective was to explore suitable conditions, at farm and downstream levels, for organic hempseed oil production in Sicily, taking on an action-research perspective that involves local actors. Based on a preliminary characterisation of barriers to organic hemp development at different value chain levels, we carried out targeted complementary investigation: (i) assessment on agroenvironmental performances of integrating hemp in durum wheat-based rotations; (ii) chemical analysis of local hempseed oil; (iii) exploration of marketing opportunities and value chain development. Our results showed that the lack of technical and economic knowledge as well as the deficiencies of suitable cultivars and adequate machinery were the main barriers for the organic hemp value chain development in Sicily. The analysis of agroenvironmental performances also revealed both strengths and weaknesses of hemp introduction in durum-wheat based rotations. Despite the identified limitations, we demonstrated that the organic hemp value chains represent interesting perspectives for the Sicilian farming sector, particularly in case of substantial barriers removal or adaptation.
Recent trends in natural resources, energy conservation, biomass conversion to chemicals, bioproducts and biofuels have renewed the interest on hemp as a new low-cost, sustainable, ecological, biodegradable, recyclable, and multi-purpose material. Hemp-based materials are indeed suitable substitutes for many fossil-based materials and applications.
Industrial hemp, Cannabis sativa (Cannabaceae), is a newly introduced and rapidly expanding crop in the American agricultural landscape. As an exclusively wind-pollinated crop, hemp lacks nectar but produces an abundance of pollen during a period of floral dearth in agricultural landscapes. These pollen resources are attractive to a range of bee species but the diversity of floral visitors and their use of hemp across a range of agricultural contexts remains unclear. We made repeated sweep net collections of bees visiting hemp flowers on farms in New York, which varied in both landscape context and phenotypic traits of hemp varieties. We identified all bee visitors to the species level and found that hemp supported 16 different bee species. Landscape simplification negatively impacted the abundance of bees visiting hemp flowers but did not affect the species richness of the community. Plant height, on the other hand, was strongly correlated with bee species richness and abundance for hemp plots with taller varieties attracting a broader diversity of bee species. Because of its temporally unique flowering phenology, hemp has the potential to provide a critical nutritional resource to a diverse community of bees during a period of floral scarcity and thereby may help to sustain agroecosystem-wide pollination services for other crops in the landscape. As cultivation of hemp increases, growers, land managers, and policy makers should consider its value in supporting bee communities and take its attractiveness to bees into account when developing pest management strategies.
Hemp (Cannabis sativa L.) is now being grown within the United States over a much broader geographic area and for different uses than during its last period of significant production that ended after World War II. Within the past 3 yr, a large number of arthropod species have been documented to feed on hemp in the United States. Among key pest species, corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), has demonstrated greatest potential for crop injury, being particularly damaging to flower buds. Hemp russet mite, Aculops cannibicola (Farkas), and cannabis aphid, Phorodon cannabis Passerini, are the two species observed most damaging among those that suck plant fluids. Eurasian hemp borer, Grapholita delineana Walker, is widely present east of the Rocky Mountains and appears to have potential to significantly damage both flower buds and developing seeds. Numerous species of caterpillars, grasshoppers, and beetles chew hemp foliage; the severity of these defoliation injuries appears to be minimal, but needs further study. Similarly, numerous seed feeding hemipterans, most notably stink bugs and Lygus bugs, are regularly found in the crop but injury potential remains unclear. Some preliminary efforts have been made to develop integrated pest management strategies for these insects, particularly for corn earworm. Future research can be expected to rapidly resolve many of the data gaps that presently restrict advancing pest management on the crop. However, a major confounding issue involves the use of pesticides on hemp. Federal agencies have not yet provided clear direction on this issue, and regulatory decisions have subsequently devolved to the states.
Agricultural intensification has resulted in loss of natural and semi-natural habitats impacting several important ecosystem services. One group of organisms that has suffered greatly are the bees and hence pollination, the supporting ecosystem service they complete. The United States Department of Agriculture (USDA) Conservation Reserve Program (CRP) has implemented conservation practices designed to improve habitat for pollinators in agroecosystems by paying to recover environmentally sensitive agricultural land from production, and restoring them by planting native grass mixes, pollinator-friendly legumes and wildflowers. Our study, aimed at demonstrating the efficacy of this practice, measured diversity and abundance of wild bee genera in the agricultural landscape of eastern semiarid regions of Colorado, USA, where CRP practices were implemented. Over our 3-year study, we obtained a total of 16,207 bees belonging to 51 genera. We found inconsistent differences in number of bee genera and abundance of bees in CRP fields supplemented with wildflowers compared to those with conventional grass seed mix. However, we observed only a 40–80% overlap in bee genera between fields supplemented with wildflowers and those with grass seed mixes indicating that diversity was enhanced by having both habitats. With the caveat that 3 years is a very short period to see appreciable changes, our results suggest that recovering environmentally sensitive land can strengthen pollinator populations in landscapes dominated by agricultural activities. In addition, periodic evaluation and maintenance of these recovered lands will further support the efforts towards revitalization of ecosystem services in these areas.
Continued loss of natural habitats with native prairies and wildflower patches is eliminating diverse sources of pollen, nectar and phytochemicals therein for foraging bees. The longstanding plant-pollinator mutualism reiterates the role of phytochemicals in sustaining plant-pollinator relationship and promoting honey bee health. We studied the effects of four phytochemicals—caffeine, gallic acid, kaempferol and p-coumaric acid, on survival and pathogen tolerance in the European honey bee, Apis mellifera (L.). We recorded longevity of worker bees that were provided ad libitum access to sugar solution supplemented with different concentrations of phytochemicals. We artificially infected worker bees with the protozoan parasite, Nosema ceranae. Infected bees were provided access to the same concentrations of the phytochemicals in the sugar solution, and their longevity and spore load at mortality were determined. Bees supplemented with dietary phytochemicals survived longer and lower concentrations were generally more beneficial. Dietary phytochemicals enabled bees to combat infection as seen by reduced spore-load at mortality. Many of the phytochemicals are plant defense compounds that pollinators have evolved to tolerate and derive benefits from. Our findings support the chemical bases of co-evolutionary interactions and reiterate the importance of diversity in floral nutrition sources to sustain healthy honey bee populations by strengthening the natural mutualistic relationships.
Bees are important pollinators of numerous crops, and monitoring their abundance and diversity in commercial agricultural ecosystems is of increasing importance due to pollinator declines. In season-long field studies conducted in Pennsylvania during 2011-2013, we evaluated five different bee monitoring passive traps - three pan traps (blue, yellow, and white) and two vane traps (blue and yellow) - for their effectiveness and utility for monitoring bees in commercial apple orchards. Traps were placed prebloom and were monitored weekly until the end of crop season (mid-October). We recorded 14,770 bees comprising 118 species, 27 genera, and five families. The most abundant species were Augochlora pura (Say) (34.4% of total), Ceratina calcarata Robertson (15.5%), Bombus vagans Smith (7.8%), Bombus impatiens Cresson (6.4%), and Apis mellifera L. (4.3%). Bee abundance was highly variable among trap types across the three years and during the bloom and postbloom period. Blue vane traps were found to be the most effective trap type, with significantly higher rates of per-sample species accumulation than all other traps. Species richness estimates were highest for the blue vane and blue pan traps. This study reveals the utility and effectiveness of various traps for studying abundance and diversity of pollinator bees in commercially managed apple orchards. It also provides baseline information about the bee community found during the bloom and postbloom periods in Pennsylvania apple orchards that can be used to measure changes in bee community structure and abundance due to conservation efforts, such as reduced risk IPM programs, habitat management, and augmentation. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America.
Significance
In 2014, a presidential memorandum called for an assessment of the nation’s pollinators, in response to growing awareness of their economic importance and recent declines. We assess, for the first time to our knowledge, the status and trends of wild bee abundance and their potential impacts on pollination services across the United States. We develop national maps of wild bee abundance, report land-use–driven changes over time, and relate them to trends in agricultural demand for pollination. We estimate uncertainty in the findings, so future research can target the least-understood regions and topics. Our findings can also help focus conservation efforts where declines in bee abundance are most certain, especially where agricultural demand for pollination services is growing.
Coloured pan trapping is a simple and efficient method for collecting flying insects, yet there is still discussion over the most effective bowl colour to use for particular target groups (e.g. pollinator insects). The success of particular colours can vary across bioregions and habitats. Most published pan trap studies have been conducted in the northern hemisphere, and very few investigated the effects of habitat on pan trap catches. Our study is one of the first to (1) sample for potential pollinators in Australian mallee vegetation and almond orchards and (2) investigate whether habitat interacts with trap colour to influence pan trap catches. We sampled Hymenoptera and Diptera using yellow, white and blue pan traps in native mallee vegetation and two types of managed almond orchards (monoculture and plant-diverse) in the Murray Mallee bioregion of north-western Victoria, Australia. Yellow traps caught the most insects across all habitats, although catches in each colour trap varied with habitat. For all insect groups combined, blue traps caught more individuals in mallee habitats than in almond orchards. For native hymenopterans, yellow traps caught more individuals in plant-diverse orchards than in native sites, while blue traps caught more individuals in native sites. Our results highlight the importance of considering the habitat of individual pan trapping surveys, as no one trap colour is likely to be suitable for trapping target insects across all habitats.
Pollination is an essential process in the sexual reproduction of seed plants and a key ecosystem service to human welfare. Animal pollinators decline as a consequence of five major global change pressures: climate change, landscape alteration, agricultural intensification, non-native species, and spread of pathogens. These pressures, which differ in their biotic or abiotic nature and their spatiotemporal scales, can interact in nonadditive ways (synergistically or antagonistically), but are rarely considered together in studies of pollinator and/or pollination decline. Management actions aimed at buffering the impacts of a particular pressure could thereby prove ineffective if another pressure is present. Here, we focus on empirical evidence of the combined effects of global change pressures on pollination, highlighting gaps in current knowledge and future research needs.
Bee pollinators are currently recorded with many different sampling methods. However, the relative performances of these methods have not been systematically evaluated and compared. In response to the strong need to record ongoing shifts in pollinator diversity and abundance, global and regional pollinator initiatives must adopt standardized sampling protocols when developing large‐scale and long‐term monitoring schemes.
We systematically evaluated the performance of six sampling methods (observation plots, pan traps, standardized and variable transect walks, trap nests with reed internodes or paper tubes) that are commonly used across a wide range of geographical regions in Europe and in two habitat types (agricultural and seminatural). We focused on bees since they represent the most important pollinator group worldwide. Several characteristics of the methods were considered in order to evaluate their performance in assessing bee diversity: sample coverage, observed species richness, species richness estimators, collector biases (identified by subunit‐based rarefaction curves), species composition of the samples, and the indication of overall bee species richness (estimated from combined total samples).
The most efficient method in all geographical regions, in both the agricultural and seminatural habitats, was the pan trap method. It had the highest sample coverage, collected the highest number of species, showed negligible collector bias, detected similar species as the transect methods, and was the best indicator of overall bee species richness. The transect methods were also relatively efficient, but they had a significant collector bias. The observation plots showed poor performance. As trap nests are restricted to cavity‐nesting bee species, they had a naturally low sample coverage. However, both trap nest types detected additional species that were not recorded by any of the other methods.
For large‐scale and long‐term monitoring schemes with surveyors with different experience levels, we recommend pan traps as the most efficient, unbiased, and cost‐effective method for sampling bee diversity. Trap nests with reed internodes could be used as a complementary sampling method to maximize the numbers of collected species. Transect walks are the principal method for detailed studies focusing on plant–pollinator associations. Moreover, they can be used in monitoring schemes after training the surveyors to standardize their collection skills.
We evaluate the empirical and theoretical support for the hypothesis that a large proportion of native species richness is
required to maximize ecosystem stability and sustain function. This assessment is important for conservation strategies because
sustenance of ecosystem functions has been used as an argument for the conservation of species. If ecosystem functions are
sustained at relatively low species richness, then arguing for the conservation of ecosystem function, no matter how important
in its own right, does not strongly argue for the conservation of species. Additionally, for this to be a strong conservation
argument the link between species diversity and ecosystem functions of value to the human community must be clear. We review
the empirical literature to quantify the support for two hypotheses: (1) species richness is positively correlated with ecosystem
function, and (2) ecosystem functions do not saturate at low species richness relative to the observed or experimental diversity.
Few empirical studies demonstrate improved function at high levels of species richness. Second, we analyze recent theoretical
models in order to estimate the level of species richness required to maintain ecosystem function. Again we find that, within
a single trophic level, most mathematical models predict saturation of ecosystem function at a low proportion of local species
richness. We also analyze a theoretical model linking species number to ecosystem stability. This model predicts that species
richness beyond the first few species does not typically increase ecosystem stability. One reason that high species richness
may not contribute significantly to function or stability is that most communities are characterized by strong dominance such
that a few species provide the vast majority of the community biomass. Rapid turnover of species may rescue the concept that
diversity leads to maximum function and stability. The role of turnover in ecosystem function and stability has not been investigated.
Despite the recent rush to embrace the linkage between biodiversity and ecosystem function, we find little support for the
hypothesis that there is a strong dependence of ecosystem function on the full complement of diversity within sites. Given
this observation, the conservation community should take a cautious view of endorsing this linkage as a model to promote conservation
goals.
The purpose of this study was to identify bee species active in pumpkin fields in New York and to estimate their potential as pollinators by examining their foraging activity. In addition, we examined whether foraging activity was affected by either the addition of hives of the honey bee, Apis mellifera L., or by field size. Thirty-five pumpkin (Cucurbita spp.) fields ranging from 0.6 to 26.3 ha, 12 supplemented with A. mellifera hives and 23 not supplemented, were sampled during peak flowering over three successive weeks in 2008 and 2009. Flowers from 300 plants per field were visually sampled for bees on each sampling date. A. mellifera, Bombus impatiens Cresson, and Peponapis pruinosa (Say) accounted for 99% of all bee visits to flowers. A. mellifera and B. impatiens visited significantly more pistillate flowers than would be expected by chance, whereas P. pruinosa showed no preference for visiting pistillate flowers. There were significantly more A. mellifera visits per flower in fields supplemented with A. mellifera hives than in fields not supplemented, but there were significantly fewer P. pruinosa visits in supplemented fields. The number of B. impatiens visits was not affected by supplementation, but was affected by number of flowers per field. A. mellifera and P. pruinosa visits were not affected by field size, but B. impatiens visited fewer flowers as field size increased in fields that were not supplemented with A. mellifera hives. Declining A. mellifera populations may increase the relative importance of B. impatiens in pollinating pumpkins in New York.
Addition of floral resources to agricultural field margins has been shown to increase abundance of beneficial insects in crop fields, but most plants recommended for this use are non-native annuals. Native perennial plants with different bloom periods can provide floral resources for bees throughout the growing season for use in pollinator conservation projects. To identify the most suitable plants for this use, we examined the relative attractiveness to wild and managed bees of 43 eastern U.S. native perennial plants, grown in a common garden setting. Floral characteristics were evaluated for their ability to predict bee abundance and taxa richness. Of the wild bees collected, the most common species (62%) was Bombus impatiens Cresson. Five other wild bee species were present between 3 and 6% of the total: Lasioglossum admirandum (Sandhouse), Hylaeus affinis (Smith), Agapostemon virescens (F.), Halictus ligatus Say, and Ceratina calcarata/dupla Robertson/Say. The remaining wild bee species were present at <2% of the total. Abundance of honey bees (Apis mellifera L.) was nearly identical to that of B. impatiens. All plant species were visited at least once by wild bees; 9 were highly attractive, and 20 were moderately attractive. Honey bees visited 24 of the 43 plant species at least once. Floral area was the only measured factor accounting for variation in abundance and richness of wild bees but did not explain variation in honey bee abundance. Results of this study can be used to guide selection of flowering plants to provide season-long forage for conservation of wild bees.
Intensive agricultural practices resulting in large scale habitat loss ranks as the top contributing factors in the global bee decline. Growing Genetically Modified Herbicide Tolerant (GMHT) crops as large monocultures has resulted extensive applications of herbicides leading to the degradation of natural habitats surrounding farmlands. Herbicide tolerance trait is beneficial for crops such as Canola (Brassica napus) that are extremely vulnerable to weed competition. While the trait in itself does not harm pollinators, growing genetically modified herbicide tolerant cultivars indirectly contributes towards pollinator declines through habitat loss. Canola, a mass-flowering crop is highly attractive to bee pollinators and the extensive adoption of the herbicide tolerant trait has led to depletion of floral resources upon completion of crop bloom. Extensive use of herbicide in and near fields with herbicide tolerant cultivars systematically eliminates semi-natural habitats around agricultural fields which consist of non-crop flowering plants. Planting pollinator strips provides floral resources for bees after crop flowering. We document the bee genera in canola and the adjoining pollinator strip. The overlap in bee genera reinforces the importance of pollinator habitats in agricultural landscape.
Current research, management and outreach programmes relevant to insect pollinator conservation are strongly focused on relationships between pollinators and insect‐pollinated crops and wild plants.
Pollinators also visit wind‐pollinated plants to collect pollen, or for nest sites and materials, but these interactions are largely overlooked. I review documented records of bee and syrphid fly species collecting pollen from wind‐pollinated plant taxa, including economically important crops, and provide the most comprehensive collation of peer‐reviewed records of pollinators visiting wind‐pollinated plants to date. I argue for more basic research into functional relationships between insect pollinators and wind‐pollinated plants.
I found over 200 visitation records for 101 wind‐pollinated plant genera in 25 families, including 4 of the 12 gymnosperm families. Almost half the records (49%) were for grasses and sedges (Poales). I also identified records of bees and/or syrphid flies visiting 10 economically important wind‐pollinated crop plant species, including three major grain crops (rice, corn, and sorghum). Most records (70%) were from indirect pollen analysis from hives, nest cells or insect bodies, highlighting the need for more direct observational studies of plant–pollinator interactions.
Insect pollinator communities require resource diversity to persist in a landscape. Hence, researchers and land managers aiming to identify links between pollinators and ecosystem function should also consider broader interactions beyond the standard traits of the entomophily syndrome.
During bloom of spring orchard crops, bees are the primary providers of pollination service. Monitoring these insects for research projects is often done by timed observations or by direct aerial netting, but there has been increasing interest in blue vane traps as an efficient passive approach to collecting bees. Over multiple spring seasons in Michigan and Pennsylvania, orchards were monitored for wild bees using timed netting from crop flowers and blue vane traps. This revealed a distinctly different community of wild bees captured using the two methods, suggesting that blue vane traps can complement but cannot replace direct aerial netting. The bee community in blue vane traps was generally composed of nonpollinating species, which can be of interest for broader biodiversity studies. In particular, blue vane traps caught Eucera atriventris (Smith), Eucera hamata (Bradley), Bombus fervidus (F.), and Agapostemon virescens (F.) that were never collected from the orchard crop flowers during the study period. Captures of bee species in nets was generally stable across the 3 yr, whereas we observed significant declines in the abundance of Lasioglossum pilosum (Smith) and Eucera spp. trapped using blue vane traps during the project, suggesting local overtrapping of reproductive individuals. We conclude that blue vane traps are a useful tool for expanding insights into bee communities within orchard crop systems, but they should be used with great caution to avoid local extirpation of these important insects.
Interest in hemp as a multi-purpose crop is growing worldwide and for the first time in 2015 it was cultivated in Europe on more than 20.000 ha as a dual-purpose crop, for the seeds and for the fibre. In the present study, fibre and seed productivity of 14 commercial cultivars were tested in four contrasting European environments (Latvia, the Czech Republic, France, Italy). At full flowering, the stem yield ranged from 3.7 Mg ha−1 to 22.7 Mg ha−1, the bast fibre content ranged from 21% to 43%, and the bast fibre yield ranged from 1.3 Mg ha−1 to 7.4 Mg ha−1. When harvesting was postponed from full flowering until seed maturity, the stem yield of monoecious cultivars significantly increased but in dioecious cultivars it decreased at all tested sites, except for Italy. Only the early cultivars Fedora 17 and Markant produced seed in the most northern location Latvia. The seed yield ranged from 0.3 Mg ha−1 to 2.4 Mg ha−1 in Italy, France and the Czech Republic. The cultivar effect on stem and seed yield was mainly determined by the genetic variation in time of flowering. Stem yield at full flowering was strictly related to the duration of the vegetative phase while seed yield was lowest in the late flowering cultivar. The late cultivar CS is suitable for stem and fibre production as it had the highest stem yield at full flowering in all locations. Both Fedora 17 and Futura 75 are candidate cultivars for dual-purpose production in Italy, France and the Czech Republic, with Fedora 17 being more suitable for seed production and Futura 75 for fibre production.
Global trends in pollinator-dependent crops have raised awareness of the need to support managed and wild bee populations to ensure sustainable crop production. Provision of sufficient forage resources is a key element for promoting bee populations within human impacted landscapes, particularly those in agricultural lands where demand for pollination service is high and land use and management practices have reduced available flowering resources. Recent government incentives in North America and Europe support the planting of wildflowers to benefit pollinators; surprisingly, in North America there has been almost no rigorous testing of the performance of wildflower mixes, or their ability to support wild bee abundance and diversity. We tested different wildflower mixes in a spatially replicated, multiyear study in three regions of North America where production of pollinator-dependent crops is high: Florida, Michigan, and California. In each region, we quantified flowering among wildflower mixes composed of annual and perennial species, and with high and low relative diversity. We measured the abundance and species richness of wild bees, honey bees, and syrphid flies at each mix over two seasons. In each region, some but not all wildflower mixes provided significantly greater floral display area than unmanaged weedy control plots. Mixes also attracted greater abundance and richness of wild bees, although the identity of best mixes varied among regions. By partitioning floral display size from mix identity we show the importance of display size for attracting abundant and diverse wild bees. Season-long monitoring also revealed that designing mixes to provide continuous bloom throughout the growing season is critical to supporting the greatest pollinator species richness. Contrary to expectation, perennials bloomed in their first season, and complementarity in attraction of pollinators among annuals and perennials suggests that inclusion of functionally diverse species may provide the greatest benefit. Wildflower mixes may be particularly important for providing resources for some taxa, such as bumble bees, which are known to be in decline in several regions of North America. No mix consistently attained the full diversity that was planted. Further study is needed on how to achieve the desired floral display and diversity from seed mixes.
Beneficial arthropods, including native bees, predators, and parasitoids, provide valuable ecosystem services worth $8 billion to US agriculture each year. These arthropod-mediated ecosystem services (AMES) Include crop pollination and pest control, which help to maintain agricultural productivity and reduce the need for pesticide inputs. Maximizing survival and reproduction of beneficial arthropods requires provision of pollen and nectar resources that are often scarce in modern agricultural landscapes. Increasingly, native plants are being evaluated for this purpose. Native plants can outperform recommended non-natives and also provide local adaptation, habitat permanency, and support of native biodiversity. We predict that the success of insect conservation programs using flowering plants to increase AMES on farmland will depend on landscape context, with the greatest success in landscapes of moderate complexity. Reintegration of native plants into agricultural landscapes has the potential to support multiple conservation goals, and will require the collaboration of researchers, conservation educators, and native plant experts.
Pollination services from wild insects contribute to crop productivity around the world, but are at risk of decline in agricultural landscapes. Using highbush blueberry as a model system, we tested whether wildflower plantings established adjacent to crop fields would increase the abundance of wild pollinators during crop bloom and enhance pollination and yield.
Plantings were seeded in 2009 with a mix of 15 perennial wildflower species that provided season‐long bloom and increased plant density and floral area during the subsequent 3 years.
Honeybees visiting blueberry flowers had similar abundance in enhanced and control fields in all 4 years of this study, whereas wild bee and syrphid abundance increased annually in the fields adjacent to wildflower plantings.
Crop pollination parameters including percentage fruit set, berry weight and mature seeds per berry were significantly greater in fields adjacent to wildflower plantings 3 and 4 years after seeding, leading to higher crop yields and with the associated revenue exceeding the cost of wildflower establishment and maintenance.
Synthesis and applications . We suggest that provision of forage habitat for bees adjacent to pollinator‐dependent crops can conserve wild pollinators in otherwise resource‐poor agricultural landscapes. Over time, these plantings can support higher crop yields and bring a return on the initial investment in wildflower seed and planting establishment, also insuring against loss of managed pollinators. Further understanding of the importance of planting size, location and landscape context will be required to effectively implement this practice to support crop pollination.
This is the third in a series of “Hemp production notes,” which focuses on the unique challenge of growing hemp at high latitudes in the European Community. This paper briefly reviews the historical considerations of hemp in Finland, addresses some of the problems inherent at high latitudes and identifies specific market potentials for the Nordic production of hemp seed as an industrial crop.
Species richness is a fundamental measurement of community and regional diversity, and it underlies many ecological models and conservation strategies. In spite of its importance, ecologists have not always appreciated the effects of abundance and sampling effort on richness measures and comparisons. We survey a series of common pitfalls in quantifying and comparing taxon richness. These pitfalls can be largely avoided by using accumulation and rarefaction curves, which may be based on either individuals or samples. These taxon sampling curves contain the basic information for valid richness comparisons, including category–subcategory ratios (species-to-genus and species-to-individual ratios). Rarefaction methods – both sample-based and individual-based – allow for meaningful standardization and comparison of datasets. Standardizing data sets by area or sampling effort may produce very different results compared to standardizing by number of individuals collected, and it is not always clear which measure of diversity is more appropriate. Asymptotic richness estimators provide lower-bound estimates for taxon-rich groups such as tropical arthropods, in which observed richness rarely reaches an asymptote, despite intensive sampling. Recent examples of diversity studies of tropical trees, stream invertebrates, and herbaceous plants emphasize the importance of carefully quantifying species richness using taxon sampling curves.
NOTE: This is not a book, contrary to what ResearchGate claims. This is a software application and User's Guide. The current version is Version 9. The citations here are incomplete, since each version has its own citations. EstimateS currently has more than 4000 citations in the peer-reviewed literature. For the full list, go to GoogleScholar: http://bit.ly/11YdUlg .
Pollinators are a key component of global biodiversity, providing vital ecosystem services to crops and wild plants. There is clear evidence of recent declines in both wild and domesticated pollinators, and parallel declines in the plants that rely upon them. Here we describe the nature and extent of reported declines, and review the potential drivers of pollinator loss, including habitat loss and fragmentation, agrochemicals, pathogens, alien species, climate change and the interactions between them. Pollinator declines can result in loss of pollination services which have important negative ecological and economic impacts that could significantly affect the maintenance of wild plant diversity, wider ecosystem stability, crop production, food security and human welfare.
Global change may substantially affect biodiversity and ecosystem functioning but little is known about its effects on essential biotic interactions. Since different environmental drivers rarely act in isolation it is important to consider interactive effects. Here, we focus on how two key drivers of anthropogenic environmental change, climate change and the introduction of alien species, affect plant-pollinator interactions. Based on a literature survey we identify climatically sensitive aspects of species interactions, assess potential effects of climate change on these mechanisms, and derive hypotheses that may form the basis of future research. We find that both climate change and alien species will ultimately lead to the creation of novel communities. In these communities certain interactions may no longer occur while there will also be potential for the emergence of new relationships. Alien species can both partly compensate for the often negative effects of climate change but also amplify them in some cases. Since potential positive effects are often restricted to generalist interactions among species, climate change and alien species in combination can result in significant threats to more specialist interactions involving native species.
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