Part 6-B: Eco-Services and CAUSES for the Decline in

The Contribution of to our Eco System Native bees are considered a 'keystone' species for almost all terrestrial : • Most wild plants depend on by for reproduction. • pollinators contribute to seed set and plant diversity. • These insects form the basis of an energy-rich food web. • Plants and their native pollinators have co-evolved over millions of years. • Certain native bees ( / Bombus species) are more efficient pollinators than honeybees. • Specialist native bumble bees can buzz pollinate certain crops, such as squashes, tomatoes, peppers, melons and cucumbers. Honey bees can not pollinate these crops.

It is estimated that in 2009 bees contributed to 11% of the nation's agricultural value, roughly $14.6 billion per year. Of this, at least 20% ($3.07 billion) is provided by wild pollinators. These important native pollinators need suitable land for nesting and foraging near the cultivated fields.

Related Research: • Kearns et al. 1998. Endangered mutualisms: the conservation of plant-pollinator interaactions. Annual Review of Ecology and Systematics 29:83-112 • Losey JE, Vaughan M. 2006. The economic value of ecological services provided by insects. BioScience 56(4):311– 323.

The Causes for Native Pollinator Decline

ONE: Land Use Intensification / Urbanization / Habitat Loss These practices contribute to the decline in pollinators: • growth of mega-scale agricultural operations; • loss of hedge rows and field borders; • excessive use of herbicides, and drift from the application of these chemicals; • large monocultures of food crops that lack habitat refuge for native bees; • overgrazing; • lawns and fields with mowing that prevents plants from flowering.

Related Research related to loss of floral diversity: • Blaauw, BR; Isaacs, R. Flower plantings increase wild bee abundance and the pollination services provided to a pollination-dependent crop. Journal of Applied Ecology 2014, 51, 890–898 A study of blueberry seed- set. From the Abstract: " Crop pollination parameters including percentage 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...... 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". • Garibaldi, LA et al: Stability of pollination services decreases with isolation from natural areas despite visits. Ecology Letters, (2011) 14: 1062–1072 From the abstract: " Mean richness, visitation and fruit set also decreased with isolation, by 34, 27 and 16% at 1 km respectively. In contrast, honey bee visitation did not change with isolation and represented > 25% of crop visits in 21 studies. Therefore, wild pollinators are relevant for crop productivity and stability even when honey bees are abundant. Policies to preserve and restore natural areas in agricultural landscapes should enhance levels and reliability of pollination services." • Kleijn, D et al. 2015 Delivery of crop pollination services is an insufficient argument for wild pollinator conservation. Nature Communications DOI: 10.1038/ncomms8414 From the Abstract: "Here we show that, while the contribution of wild bees to crop production is significant, service delivery is restricted to a limited subset of all known bee species. Across crops, years and biogeographical regions, crop-visiting wild bee communities are dominated by a small number of common species, and threatened species are rarely observed on crops. Dominant crop pollinators persist under agricultural expansion and many are easily enhanced by simple conservation measures, suggesting that cost-effective management strategies to promote crop pollination should target a different set of species than management strategies to promote threatened bees. Conserving the biological diversity of bees therefore requires more than just -service-based arguments." • Koh, Insu et al. Modeling the status, trends, and impacts of wild bee abundance in the United States. PNAS 2016 January, 113 (1) 140-145. From the Abstract: " ... Between 2008 and 2013, modeled bee abundance declined across 23% of US land area. This decline was generally associated with conversion of natural habitats to row crops. We identify 139 counties where low bee abundances correspond to large areas of pollinator-dependent crops. These areas of mismatch between supply (wild bee abundance) and demand (cultivated area) for pollination comprise 39% of the pollinator-dependent crop area in the United States. Further, we find that the crops most highly dependent on pollinators tend to experience more severe mismatches between declining supply and increasing demand. These trends, should they continue, may increase costs for US farmers and may even destabilize crop production over time." NOTE: much of this land was converted to corn for biofuel. • Potts, SG et al. 2010. Global pollinator declines: trends, impacts and drivers Trends in Ecology and Evolution Vol.25 No.6 From the Abstract: " Pollinators are a key component of global , 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, 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." • Ricketts, TH et al. Economic value of tropical forest to coffee production. PNAS 2004 , vol. 101 no. 34 pp 12579–12582 Researchers have found that growing coffee near native forest ecosystems increases coffee bean yield by 20% within 1 km of forest edge and reduced the number of 'peaberries' [small misshapen beans] by 27%/ Thus, from the Abstract: "Conservation investments in human-dominated landscapes can therefore yield double benefits: for biodiversity and agriculture".

Excessive Lawn Care: Lawns comprise 50% of urban land. At the Pollinator Partners' June 2017 field trip where her experiments with suburban ecosystems were discussed, Susannah Lerman of U Mass gave a talk titled Mow Less for More Buzz. She has surprising results from experiments in Springfield MA, where homeowners committed to less mowing and no chemicals for lawn care ( / herbicide / fertilizers) for two years.

Several articles have resulted from these experiments that suggest less lawn care contributes to a remarkable boost in the biodiversity of bees and plants, creating an oasis in what was believed to be a pollinator desert! • Lerman, SB; Milam, J. 2016. Bee Fauna and Floral Abundance Within Lawn-Dominated Suburban Yards in Springfield, MA , Annals of the Entomological Society of America, Volume 109, Issue 5, Pages 713–723 • Lerman, SB et al. 2018. To mow or to mow less: Lawn mowing frequency affects bee abundance and diversity in suburban yards. 'Biological Conservation Volume 221, Pages 160–174. This article suggests we should be a 'lazy lawnmower' -- from the Abstract: 'Lawns mowed every three weeks had as much as 2.5 times more lawn flowers than the other frequencies. Interestingly, lawns mowed every two weeks supported the highest bee abundance yet the lowest bee richness and evenness.' .... 'Mowing less frequently is practical, economical, and a timesaving alternative to lawn replacement or even planting pollinator gardens. Given the pervasiveness of lawns coupled with habitat loss, our findings provide immediate solutions for individual households to contribute to urban conservation.' The researchers counted 93 species of bees, accounting for about a quarter of all bee species in Massachusetts. They suggest this demonstrates that urban environments, if managed properly, can provide suitable habitat for high diversity N.H. Wildlife Action Plaandn abundancecontinu ofe bees.d

Neonicotinoids [“neonics”TWO:] are br oad Over spec Reliancetrum insec tOnicid eChemicalss applied both to foliage and Someto seeds which abs areor worseb them than int oothers: Certain chemicals can be used conservatively, with few side effects. Others have wide-ranging secondary impacts. Organic gardening and the growing plant. The inseagriculturalcticide acc measuresumulates are in nimportantectar an ind protecting the health and variety of pollinators. pollen, which bumble bees consume. create many problems: These chemicals are fairly new, with use starting in 1994 and one, Imidacloprid, is now the Exposure causes increased most commonly used in agriculture in the US and elsewhere, with queen mortality, reduced billions of pounds used each year. Nearly movements in workers and 95% of corn and canola crops are grown reduced storage of nectar with this , often in the form of seed coating; other major crops are also (Scholer and Krischik 2014). grown with the chemicals at slightly lower rates. Most countries in Europe, some cities and Ontario Canada, have banned them or put strict limits on their use. When the decline in bee populations was first recognized, increased use of these chemicals seem to be correlated with the caglecartoons.com pollinator decline; recent research confirms the suspicion.

Why these products are so harmful to insects and the environment: • Systemic – the entire plant is toxic to insects, including pollen and nectar. • Persistent – can remain in soil for several months or years. • High Concentrations Recommended – while these chemicals are not so toxic to mammals, some are extremely toxic to insects, and the levels recommended for ornamental use are highly toxic to beneficial insects such as bees. • Pesticide Resistance – unnecessary use, such as coated seeds, leads to increased pest resistance to the chemicals (example: potato beetle). • Reduced Use of Integrated Pest Management (IPM) – heavy use of these chemicals means beneficial insects (lady bugs, lacewings) may be killed. Preventative farm practices, such as reducing conditions that favor pests, may be abandoned. • – the chemicals are water-soluble and can reach streams. • Doom For Ground-Nesting Bees – 70% of native bees nest in ground. Many bees use soil in building nests, and could contaminate their broods by using the contaminated soil.

The formulations vary a bit depending on use. Here are the most problematic versions: Imidacloprid, , Dinotefuran, Thiamethoxam, and Acetamiprid.

Homeowners should be aware of these formulations as they are sold in gardening centers for homeowners' lawn and garden care, and carry names, such as Bug be Gone, that belie their long-term effects on environment.

The Xerces Society has an excellent brochure that lists some of the products, their uses and brand names. The group has released a report titled How Neonicotinoids Kill Bees that summarizes extensive research on this topic.

Herbicides are a major cause for loss of pollinator plants: Herbicide use has increased dramatically since the introduction of 'roundup ready' GMO seeds (corn, soy and other crops), the plants resist glyphosate-based chemicals such as Roundup and discourage certain conservative practices such as crop rotation, cover crops and cultivation practices that reduce weeds and enrich the soil. The tendency to use herbicide on crops causes the loss of other flowering plants nearby, reducing the food and nesting options for pollinators.

Related Research: These recent articles have helped confirm the impact of neonicotinoids on pollinators: • Woodcock, BA et al. 2017. Country-specific effects of pesticides on honey bees and wild bees. Science 356, 1393–1395 This study confirms that neonicotinoids diminish bee heath. From the Abstract: " Neonicotinoid seed dressings have caused concern world-wide. We use large field experiments to assess the effects of neonicotinoid-treated crops on three bee species across three countries (Hungary, Germany, and the United Kingdom). Winter-sown oilseed rape was grown commercially with either seed coatings containing neonicotinoids (clothianidin or thiamethoxam) or no seed treatment (control). For honey bees, we found both negative (Hungary and United Kingdom) and positive (Germany) effects during crop flowering. In Hungary, negative effects on honey bees (associated with clothianidin) persisted over winter and resulted in smaller colonies in the following spring (24% declines). In wild bees (Bombus terrestris and Osmia bicornis), reproduction was negatively correlated with neonicotinoid residues. These findings point to neonicotinoids causing a reduced capacity of bee species to establish new populations in the year following exposure." • Tsvetkov, N. 2017. Chronic exposure to neonicotinoids reduces honeybee health near corn crops. Science Vol. 356, Issue 6345, pp. 1395-1397. The researchers quantified the duration and magnitude of neonicinotoid exposure in the field, finding that colonies near corn fields over a 4-month period (the honeybee normal active time), honeybees suffered increased worker mortality, a decline in survival, immune responses and increased queenlessness. Further, in presence of certain fungicide, toxicity was doubled. The study demonstrates that field-realistic exposure to neonicotinoids can reduce honey bee health in corn- growing areas.

THREE: Pests, Diseases and Competition from Honeybees With the intensive use of honeybees for large agricultural fields, or even exotic bumblebees for use in commercial greenhouses, it is established that some diseases have spread from these bees to native ones.

The classic book about pollinator declines, The Forgotten Pollinators by Stephen Buchmann and Gary Nabhan, sounded the alarm in 1996. In Chapter 10, the authors reported that honeybees can out-compete native bees since they have scouts to detect and dance to direct their peers to rapidly reach new sources of pollen and nectar; further, they can decide which are the best sources to plan an expedition. Because honeybees are so numerous (their hives have thousands of bees), they can quickly deplete a fresh pollen and nectar supply, leaving little to native pollinators. For some wild plants, honeybees will take the floral resources, but don't do a good job of pollinating the plant, so seed set is greatly reduced and native plant communities decline. Also, see section 3.B for a discussion on the resource competition with honeybees and threat to native eco-systems.

Related Research: • Buchman, SL, Nabhan, GP. 1996. The Forgotten Pollinators. Island Press (available in Howe Library). • Colla, SR et al. 2006. Plight of the bumble bee: Pathogen spillover from commercial to wild populations Biological Conservation 129 461–467 . From the abstract: " We examined the prevalence of four pathogens in wild bumble bee populations at locations near and distant to commercial greenhouses in southern Ontario, Canada. Bumble bees collected near commercial greenhouses were more frequently infected by those pathogens capable of being transmitted at flowers (Crithidia bombi and Nosema bombi) than bees collected at sites away from greenhouses. We argue that the spillover of pathogens from commercial to wild bees is the most likely cause of this pattern and we discuss the implications of such spillover for bumble bee conservation." • Fürst, MA et al. Disease associations between honeybees and bumblebees as a threat to wild pollinators. Nature. 2014 Feb 20;506(7488):364-6 • Geldmann, J; González-Varo, JP. 2018. 'Conserving honeybees does not help wildlife' Science Vol. 359, Issue 6374, pp. 392-393 This article has links to supporting research literature. • Graystock, P et al. 2016. Do managed bees drive parasite spread and emergence in wild bees? International Journal for Parasitology:Parasites and Wildlife 5 (2016) 64e75 67

FOUR: With , populations of native bumblebees may become insular; their colonies may be reduced due lack of diversity in the local native bee species, thus little diversity among bees (or colonies of bumble bees). If a queen cannot locate an un-related male bee, but instead mates with a genetically-related male, the eggs may develop as if unfertilized and turn into males, a cost to the colony, with colony a probability. This genetic phenomenon, called haplodiploidy, seems to be a cause of some social declines. Bees also need habitat corridors that connect habitat patches to help increase genetic diversity.

Related Research Parker, L and Owen, R. 2001. Population genetic aspects of pollinator decline. Conservation Ecology 5(1): 4

FIVE: Climate Change Native plants may decline, become threatened or altered: With climate change, plants that bloom early in the season may emerge earlier in the year, while bees are still in hibernation, so that flowers are not pollinated in time to generate seeds. Some species of plants may move north with climate change, but bees have been observed unable to alter their range. Another result of climate change is that the composition of pollen in crops has been altered over time by associated increases in CO2 and may affect our native bees' diet of native plant or food-crop pollen.

Related Research: • Kerr, JT et al. Climate change impacts on bumblebees converge across continents. Science, 10 July 2015 Vol 349 issue 6244 From the abstract: on bees ..."We found cross-continentally consistent trends in failures to track warming through time at species’ northern range limits, range losses from southern range limits, and shifts to higher elevations among southern species. These effects are independent of changing land uses or pesticide applications..." It seems that bees are not migrating along with the plants that they pollinate • Ziska, LH et al. 2016. Rising atmospheric CO2 is reducing the protein concentration of a floral pollen source essential for North American bees. Proceedings of the Royal Society, Biological Sciences. Proc. R. Soc. B 283: 20160414 From the introduction: "...there is substantive evidence that the nutritional content of agriculturally important food crops will decrease in response to rising levels of atmospheric carbon dioxide" This study of the pollen from plant specimens of Canadian goldenrod (Solidago canadensis), dating from 1842 to 1998 and supplemental "data with S. canadensis samples obtained in situ from Maryland (2008, 2012, 2014) and Texas (2012, 2014)". Although the atmosopheric carbon record is over a 170 year period, the bulk of the increase occurred "since the latter half of the twentieth and early twenty-first century (i.e. Ca has risen from approx. 315 ppm in 1960 to 398 ppm in 2014); consequently, the largest decrease in pollen protein for S. canadensis has occurred during that time". The implications for future of food crops and bee health are of concern if protein declines; recall that high quantity and quality of protein in pollen is essential for bees.