Land-use change reduces habitat suitability for supporting managed honey bee colonies in the Northern Great Plains

Abstract

Human reliance on insect pollination services continues to increase even as pollinator populations exhibit global declines. Increased commodity crop prices and federal subsidies for biofuel crops, such as corn and soybeans, have contributed to rapid land-use change in the US Northern Great Plains (NGP), changes that may jeopardize habitat for honey bees in a part of the country that supports >40% of the US colony stock. We investigated changes in biofuel crop production and grassland land covers surrounding ∼18,000 registered commercial apiaries in North and South Dakota from 2006 to 2014. We then developed habitat selection models to identify remotely sensed land-cover and land-use features that influence apiary site selection by Dakota beekeepers. Our study demonstrates a continual increase in biofuel crops, totaling 1.2 Mha, around registered apiary locations in North and South Dakota. Such crops were avoided by commercial beekeepers when selecting apiary sites in this region. Furthermore, our analysis reveals how grasslands that beekeepers target when selecting commercial apiary locations are becoming less common in eastern North and South Dakota, changes that may have lasting impact on pollinator conservation efforts. Our study highlights how land-use change in the NGP is altering the landscape in ways that are seemingly less conducive to beekeeping. Our models can be used to guide future conservation efforts highlighted in the US national pollinator health strategy by identifying areas that support high densities of commercial apiaries and that have exhibited significant land-use changes.apiary selection models | Apis mellifera | land use | land-cover trends | pollinators A nimal pollination service is critical for sustaining ecosystem health and human well-being (1, 2). In many terrestrial systems, plant-pollinator interactions provide the basic framework for all other trophic interactions. Globally, about one-third of crop production depends on animal pollination (3). US agricultural production relies heavily on managed and native insects for pollination services, with an estimated economic value of $15 billion annually (2). Reliance on insects for pollination services is growing even as populations of native and managed pollinators exhibit concurrent declines (4, 5). For example, in 2013−2014, total US honey bee colony losses were 34%, but beekeepers on average lost 51% of their colonies (6). Declines in managed honey bees and native bees put significant pressure on global food supplies, plant-pollinator networks, agricultural producers, and ecosystem function (7,8).Proposed reasons for the declines include parasites, diseases, agro-chemical use, forage availability, and land-use change (9, 10). Much of the research investigating anthropogenic disturbance effects on managed and native pollinators focuses on pesticides and less so on habitat fragmentation, land-use, and loss of forage. Although a paucity of data exists for most parts of the world, recent research indicates that land use influences honey ...

Consistent pollen nutritional intake drives bumble bee (Bombus impatiens) colony growth and reproduction across different habitats

“…However, studies examining how variation in landscape influences bee health have focused on managed Apis mellifera honey bees (Otto, Roth, Carlson, & Smart, 2016; Requier et al., 2015; Smart, Pettis, Euliss, & Spivak, 2016; Smart, Pettis, Rice, Browning, & Spivak, 2016; Sponsler & Johnson, 2015). It is therefore not necessarily accurate to extrapolate the results of these studies to solitary bees or bumble bees, which have substantially smaller, annual colonies.…”

Cropping pattern changes diminish agroecosystem services in North and South Dakota, USA

“…These types of analyses are improving due to increasing availability of datasets, tools, and new methodology for geospatial analyses. These techniques have been applied recently to smaller scale research to identify local, more subtle trends in land use and cropping patterns specific to the Dakotas (Arora & Wolter, ; Auch et al., ; Otto et al., ; Reitsma et al., ).…”

“…A primary driver of this was the 2007 Energy Independence and Security Act (EISA), which revised the 2005 Renewable Fuels Standard to call for a 900% increase in production of renewable fuels, from 4 billion gallons in 2006 to 36 billion gallons by 2022, with up to 21 billion gallons of advanced biofuels (i.e., noncorn starch based; US Congress, ). Some research suggests that the effects of EISA can be seen with greater cropland conversion occurring in closer proximity to ethanol refineries (Miao, ; Motamed et al., ; Otto et al., ; Wright et al., ), though this relationship may be complicated by indirect effects of increased crop prices due to ethanol expansion (Li, Miao, & Khanna, ).…”

“…In recent years, researchers have noted upward trends in overall cropland area (i.e., agricultural expansion) in these states (Auch, Xian, Laingen, Sayler, & Reker, ; Wimberly et al., ), which has been mirrored by declines in natural grasslands (Lark et al., ; Otto, Roth, Carlson, & Smart, ). In conjunction with expansion of total area, crop rotations are becoming less diverse (i.e., rotation simplification), increasingly dominated by corn ( Zea mays L.) and soybean [ Glycine max (L.) Merr.]…”

Mapping floral resources for honey bees in New Zealand at the catchment scale

“…, Williams and Carreck , Otto et al. ). Overcrowding of bee colonies can lead to diminishing returns unless the floral resources are augmented to support the honey production (Al‐Ghamdi et al.…”