Exotic plants growing in crop field margins provide little support to mango crop flower visitors

Indirect interactions between crops and natural vegetation through flower visitors: the importance of temporal as well as spatial spillover

“…Flower abundance is often an important predictor of indirect interactions, as a greater number of flowers equates to a greater chance of being encountered, patches containing many flowers can be more easily detected (Schiestl and Johnson, 2013), and pollinators tend to visit more inflorescences in larger patches of flowers (Goulson, 2000). That the strength of indirect effects increased with flower abundance at a greater rate for weeds and exotic plant species flowering in mango fields than for species growing in natural vegetation highlights the value of weeds in supporting flower visitors, an observation that has been noted elsewhere (Carvalheiro et al, 2011;Nel et al, 2017). This may be because (a) flowering plants in natural vegetation are more dispersed; (b) weeds flowered consistently and abundantly; and (c) weeds are in close proximity to the mango flowers, so energy expenditure to reach these flowers is minimised.…”

“…Flower visitor species that are active for longer periods of the year than crop flowers are available require alternative resources before and/or after crop flowering to sustain populations, and the plant species that provide these resources can therefore be viewed as playing a facilitative role. Facilitative spillover effects can therefore occur not only in space, but also over time (Bjerknes et al, 2007), as native wild or exotic plant species may support crop pollinators when crops are not in flower (Nel et al, 2017). Crops may also play this role, as early flowering crops can also support pollination of late-flowering crops (Riedinger et al, 2014).…”

Pollinator‐mediated interactions between cultivated papaya and co‐flowering plant species

“…To estimate the indirect influence of the pollinators of cultivated papaya on the co‐flowering community and vice versa, the index was calculated first with cultivated papaya as the acting plant and then as the target plant. In the context of pollinator‐mediated interactions, Müller's index is also a proxy for how much each of the acting plants contributes to the diet of all pollinators shared with each target plant (Bergamo et al, ; Carvalheiro et al, ; Nel et al, ). Müller's index goes from zero (no pollinator sharing, small contribution to the diet of shared pollinators) to one (all pollinator are shared, large contribution to the diet of shared pollinators) (Bergamo et al, ; Carvalheiro et al, ; Nel et al, ).…”

“…Intensively grown crops usually offer an unsuitable habitat and limited ephemeral floral resources to pollinators (Nel et al, ); however, pollination services in these agroecosystems are often influenced by the structure of the landscape in which the crop is embedded (Klein et al, ; Kremen et al, ; Power, ; Ricketts, ; Stanley & Stout, ). Contemporary landscape mosaics may offer floral resources and suitable habitats to pollinators mainly in forest remnants or secondary vegetation located in the vicinity of crops (Bailey et al, ; Carvalheiro, Seymour, Nicolson, & Veldtman, ; Power, ).…”

The Impact of Invasive Aliens Species of Plant in Dryland Crop Production

“…However, they still will interact with each other in life only in terms of the fulfillment of the factors supporting the growth but also the competition in terms of reproduction. According to Nel et al [28] the presence of invasive plants become competitors of other plants that can reduce pollination by insects. The statement was supported by Gross et al [29] which states that an estimated more than 85% of plants in the world take the role of insect pollinators.…”