Movement and phenology of bees in a subtropical Australian agricultural landscape

Abstract

Bees are mobile organisms that seek food and nesting opportunities from a range of habitats. It is important to understand the way they move in agricultural landscapes if we are to conserve them and benefit from their activity as pollinators. We surveyed bees using directional flight interception (Malaise) traps over a 1-year period in two agricultural landscapes in south-east Queensland, Australia. We placed traps at the ecotone between crops and remnant vegetation to establish the pattern of movement between these habitats. Species richness in these landscapes (70) was high relative to that in comparable studies. Some bees were active year round, but most were caught in the period September to March. Across the whole assemblage there was a significant pattern where more species were detected leaving rather than entering remnant vegetation. The same bias was true for the number of individuals of the two most abundant species (Homalictus urbanus and Apis mellifera). Species exclusively found in crops were smaller on average (and therefore have smaller foraging range) than their non-crop counterparts. Together, these patterns indicate that while bees are abundant in crop habitat, the remnant vegetation is important as the point of origin for bee movements, and the riparian remnant in particular is richer than the dry native remnant. Compositional similarity among samples was significantly explained by landscape but also movement direction (i.e. to or from the riparian remnant) because different species showed different patterns of response.The landscape with greater native vegetation cover supported more species in and around crops than the landscape with less native vegetation.

Profiling crop pollinators: life history traits predict habitat use and crop visitation by Mediterranean wild bees

“…However, the sensitivity of pollinators to agricultural management and other types of anthropogenic disturbance depends upon specific pollinator life history traits such as nesting guild, dietary specialization, and social organization (Winfree et al 2009, Williams et al 2010. This ecotone can be a major barrier to some pollinator species, distinguishing between species that are found in nearby habitats, but do not cross the ecotone into fields, and those who do (Cunningham et al 2013, Pe'er et al 2011. A unique feature of agricultural landscapes is the very sharp change (ecotone) in physical structure and in the diversity, abundance, and phenology of nesting and foraging resources that occurs between the agricultural area and the surrounding habitats (Mandelik et al 2012).…”

“…A unique feature of agricultural landscapes is the very sharp change (ecotone) in physical structure and in the diversity, abundance, and phenology of nesting and foraging resources that occurs between the agricultural area and the surrounding habitats (Mandelik et al 2012). This ecotone can be a major barrier to some pollinator species, distinguishing between species that are found in nearby habitats, but do not cross the ecotone into fields, and those who do (Cunningham et al 2013, Pe'er et al 2011. A further difference among crop pollinators may lie in their response to increased isolation from natural habitats when moving from the field edge to its interior; some species disappear towards the field interior, while others persist (Ricketts 2004, Chacoff andAizen 2006).…”

Early-season movement dynamics of phytophagous pest and natural enemies across a native vegetation-crop ecotone

“…There is a high contrast between NV and the adjacent crop fields in terms of vegetation structure and composition, which may limit movement across this ecotone for certain species (Ries and Debinski, 2001;Cunningham et al, 2013). Campbell et al (2011) used flight interception traps to show that the movement of beetles across two ecotones with different degrees of contrast varied considerably.…”

Old fields increase habitat heterogeneity for arthropod natural enemies in an agricultural mosaic

“…Where this leads to high species turnover among patches, it can enhance overall biodiversity across the landscape (Vrdoljak and Samways, 2013). Patch diversity can also benefit species that show complementary habitat use, as they move among mosaic elements and exploit resources provided by different patch types (Cunningham et al, 2013;Mandelik et al, 2012), a behaviour which is considered to be an important mechanism for persistence in these fragmented environments (Mandelik et al, 2012).…”