Rangeland sharing by cattle and bees: moderate grazing does not impair bee communities and resource availability

Abstract

Rangelands are a dominant anthropogenic land use and a main driver of natural habitat loss worldwide. Land sharing, the integration of agricultural production and biodiversity conservation, may provide a platform for managing rangelands to fulfill multiple ecosystem services. However, livestock grazing can greatly affect biodiversity and little is known about its effects on providers of focal ecosystem services, such as pollinators. We investigated the effect of cattle grazing on bee communities and their foraging and nesting resources in Mediterranean rangelands. Specifically, we explored the effect of moderate cattle grazing on flowering plant abundance, species richness and composition, the diversity of nesting substrates, and consequently, the possible effects on wild bee and honey bee foraging activity, species diversity, and community composition. We conducted field research in the Mediterranean rangelands of Israel during the main bee activity season, in the spring of 2012 and 2013, comparing paired cattle‐grazed and ungrazed areas. The availability of floral and nesting resources for bees was unaffected or positively affected by grazing. Similarly, wild bee abundance, species richness, and composition were not affected by grazing, but were instead shaped by spatiotemporal factors. Nor was honey bee activity level impaired by grazing. The foraging preferences of bees, as well as flower species composition and peak bloom differed between grazed and ungrazed areas. Therefore, in our studied rangelands, grazing had its main effect on the foraging choices of honey bees and wild bees, rather than on their abundance and diversity. Moreover, our results indicate the potentially important role of ungrazed patches in increasing nectar and pollen diversity and availability in rangelands for both honey bees and wild bees in the spring. Hence, maintaining a mosaic of moderately grazed and ungrazed patches is expected to provide the greatest benefits for wild bee conservation and honey bee activity in Mediterranean rangelands. Our findings support the notion of rangeland sharing by cattle and bees in Mediterranean ecosystems under moderate grazing intensities, mimicking the coexistence of honey bees, wild bees, and cattle in Mediterranean ecosystems on an evolutionary timescale.

A meta‐analysis of the effects of habitat aridity, evolutionary history of grazing and grazing intensity on bee and butterfly communities worldwide

“…communities in a semi-arid prairie system in Oregon (USA), and showed that cattle presence caused soil compaction and a reduction in herbaceous litter. In contrast, tests of cattle-mediated effects on bee communities in arid Mediterranean habitats reported null effects on wild bee abundance and richness, despite impacts on forb communities and bee foraging preferences (Shapira et al, 2019).…”

Pollinator research provides conservation management implications in North Dakota

“…Cattle grazing is often reported to be disruptive to floral resource availability (Kimoto et al, 2012), but patchburn grazing helps to concentrate cattle in recently burned areas (Spiess et al, 2020), creating the necessary heterogeneity to support diverse pollinator communities (Kimoto et al, 2012;Hanberry et al, 2021;Samways et al, 2020). Our treatments likely needed additional time to develop, but they are predicted to increase land sharing between pollinators and livestock, similar to rangelands in Israel (Shapira et al, 2020).…”

“…Land sharing-management to benefit multiple ecosystem services-will be necessary as the amount of high-functioning native landscapes decreases due to erosion or urbanization (Cole et al, 2017;Öckinger & Smith, 2007;Sieverding et al, 2020). Instead of confining livestock production to rangelands and pollinator conservation to conservations lands (CRP, wildlife refuges), both efforts can be management goals in rangelands (Polasky et al, 2005;Senapathi et al, 2015;Shapira et al, 2020).…”

Management linked to ecological intensification supports pollinator abundance in Iberian wood-pastures

“…Much research has been conducted on the effects of livestock grazing on plants, from the individual to community level (Herrero-Juregui and Oesterheld, 2018). However, the cascading plant-mediated effects of grazing on higher trophic levels have been less studied, especially the effects on herbivorous ecosystem service providers, which rely on, or are directly affected by, plant communities (Shapira et al, 2020). Management and livestock pressure intensity in pastures are expected to have an important effect on the vegetation and consequently on ower-visiting insects, through a modi cation of the abiotic conditions and of the overall availability, quality, and phenology of pollinators' oral and nesting resources in the landscape (van Klink et al, 2015).…”

“…Many of these studies have found negative effects of increased grazing on insect pollinators due to decreased ower diversity and altered plant species composition (Kruess and Tscharntke, 2002;Minckley, 2014;Sjödin et al, 2008;Tadey, 2015), while others have shown instead positive impacts of increased grazing intensity compared to low or no-grazing sites (Carvell, 2002;Öckinger et al, 2006;van Klink et al, 2016). In the Mediterranean region, the few existing studies have shown that intermediate levels of grazing favored either pollinator abundance and richness or pollinator foraging resources (Lázaro et al, 2016;Shapira et al, 2020). Discrepancies among studies are likely the result of differences in habitat types and land-use histories, grazing level, and additional interacting management practices.…”