TEXT 1

Differences of fl oral resource use between honey bees and wild bees in an intensive farming system

1. Bees provide an essential pollination service for crops
2. and wild plants. However, substantial declines in bee
3. populations and diversity have been observed in Europe
4. and North America for the past 50 years, partly due to the
5. loss of natural habitats and reduction of plant diversity
6. resulting from agricultural intensifi cation. To mitigate
7. the negative effects of agricultural intensifi cation, agrienvironmental
8. schemes (AES) have been proposed to
9. sustain bees and other pollinators in agrosystems. AES
10. include the preservation of semi-natural habitats such as
11. grasslands, fallows, woodlots, hedgerows or set-aside
12. fi eld margins. However, empirical evidence suggests that
13. the use of those semi-natural habitats by bees may vary
14. greatly among bee functional groups and may further
15. be infl uenced by the presence of alternative foraging
16. habitats such as mass-fl owering crops. The present study
17. sets out to investigate whether the three bee groups
18. typically targeted by AES (honey bees, bumble bees
19. and other wild bees) differ in the way they use those
20. semi-natural habitats relative to common mass-fl owering
21. crops (oilseed rape, sunfl ower, alfalfa) in an intensive
22. agricultural farming system. A clear segregation pattern in
23. the use of fl oral resources appeared between honey bees
24. and wild bees, with the former being tightly associated
25. with mass-fl owering crops and the latter with semi-natural
26. habitats. Bumble bees had an intermediate strategy and
27. behaved as habitat generalists. Therefore, it would be
28. sensible to treat the three bee groups with distinct AES
29. management strategies, and to further consider potential
30. effects on AES effi ciency of alternative foraging habitats in
31. the surrounding. This study also stresses the importance
32. of native fl oral resources, particularly in semi-natural
33. herbaceous habitats, for sustaining wild bee populations.

http://www.sciencedirect.com/science/journal/01678809. Acesso em set 2013.

The sequence in which information is presented in text 1 is: