Predicting bee community responses to land-use changes: Effects of geographic and taxonomic biases

Abstract

Land-use change and intensification threaten bee populations worldwide, imperilling pollination services. Global models are needed to better characterise, project, and mitigate bees' responses to these human impacts. The available data are, however, geographically and taxonomically unrepresentative; most data are from North America and Western Europe, overrepresenting bumblebees and raising concerns that model results may not be generalizable to other regions and taxa. To assess whether the geographic and taxonomic biases of data could undermine effectiveness of models for conservation policy, we have collated from the published literature a global dataset of bee diversity at sites facing land-use change and intensification, and assess whether bee responses to these pressures vary across 11 regions (Western, Northern, Eastern and Southern Europe; North, Central and South America; Australia and New Zealand; South East Asia; Middle and Southern Africa) and between bumblebees and other bees. Our analyses highlight strong regionally-based responses of total abundance, species richness and Simpson's diversity to land use, caused by variation in the sensitivity of species and potentially in the nature of threats. These results suggest that global extrapolation of models based on geographically and taxonomically restricted data may underestimate the true uncertainty, increasing the risk of ecological surprises.

A global synthesis of the effects of diversified farming systems on arthropod diversity within fields and across agricultural landscapes

“…Research on the impacts of organic farming and in‐field plant diversity has primarily focused on beneficial functional groups such as natural enemies and pollinators (Crowder, Northfield, Strand, & Snyder, ; Kennedy et al., ) across intensively sampled regions of Europe and North America (De Palma et al., ; Shackelford et al., ). Moreover, almost all studies rely on richness (the number of taxa; Table S1) as a proxy for biodiversity but ignore metrics such as evenness (the relative abundances among species; Table S1) (e.g., Bengtsson, Ahnström, & Weibull, ; Tuck et al., ).…”

Impact of human disturbance on bee pollinator communities in savanna and agricultural sites in Burkina Faso, West Africa

“…Areas where food production most highly depends on animal pollination are also those for which the fewest data are available (Archer, Pirk, Carvalheiro, & Nicolson, 2014; Gallai, Salles, Settele, & Vaissière, 2009), due to a lack of infrastructure and funding in many areas of the world, particularly in developing countries. These same areas are often poorly buffered against disruption of ecosystem service provision from whatever cause, meaning that effects of any ecological incidents on human well‐being could be more severe here than elsewhere (De Palma et al., 2016). The fact that almost half the studies on pollinator decline comes from only five countries (Australia, Brazil, Germany, Spain and USA), with only 4% of the data from the African continent (Archer et al., 2014; Winfree, Bartomeus, & Cariveau, 2011), highlights the bias in information and the lack of data from some regions.…”

“…Furthermore, existing studies overrepresent bumblebees (which do not occur in most of Africa), and model results may not be generalized to other regions and taxa (De Palma et al., 2016). …”

Influence of bioenergy crops on pollinator activity varies with crop type and distance

“…A global decline in insect pollinator abundance and diversity is well established and associated ramifications for crop and wildflower pollination widely debated (De Palma et al, ; Hallmann et al, ; Potts et al, ; Vanbergen & Insect Pollinator Initiative, ; but see Ghazoul, ). The impact of agricultural intensification on insect pollinators like bees has received particular attention, driving major declines in both wild and managed species (Biesmeijer et al, ; Goulson, Hanley, Darvill, Ellis, & Knight, ; Vanbergen & Insect Pollinators Initiative, ).…”