Testing direct and indirect road edge effects on reproductive components of anemochoric plants

Road edge effects consist of changes in abiotic and biotic conditions resulting from the new artificial boundaries on the vegetation that are created by a road. It is known that edge effects can have variable direct and indirect influences on the biota, can be species-specific and also site-specific. However, edge effects for most plant species and most of their respective reproductive components have not been assessed yet, especially for anemochoric plants, which can directly influence the ecosystem structure. Here we evaluated directly and indirectly road edge effects on plant reproductive components (floral visiting bees, fruiting, diaspore herbivory, and diaspore dispersal) of three abundant and sympatric Malpighiaceae anemochoric species in a Brazilian savanna (Cerrado) reserve. We showed that (i) there are direct and indirect road edge effects on the reproductive components of the three anemochoric species; (ii) the road edge effects were not species-specific for all reproductive components, except for floral visiting bees; and (iii) edge influences in plants reproductive components in the cerrado sensu stricto area are restricted to 30 m from the road, except for fruit production. Our results suggest that anthropogenic changes in the landscape should be assessed in detail, as changes that are often considered to be negligible and that are believed to not cause negative damage to the structure of ecosystem, may have impacts on it. A mitigating measure is to avoid fragmentation of forest areas, such as the construction of dirt roads that cross preserved areas.

Automated summary

Road edge effects have direct and indirect influences on plant reproductive components, with varying species-specific responses. Wind-dispersed plants in a Brazilian savanna reserve are affected by road edge effects up to a distance of 30 meters.