34 research outputs found
Ecosystem restoration strengthens pollination network resilience and function.
Land degradation results in declining biodiversity and the disruption of ecosystem functioning worldwide, particularly in the tropics. Vegetation restoration is a common tool used to mitigate these impacts and increasingly aims to restore ecosystem functions rather than species diversity. However, evidence from community experiments on the effect of restoration practices on ecosystem functions is scarce. Pollination is an important ecosystem function and the global decline in pollinators attenuates the resistance of natural areas and agro-environments to disturbances. Thus, the ability of pollination functions to resist or recover from disturbance (that is, the functional resilience) may be critical for ensuring a successful restoration process. Here we report the use of a community field experiment to investigate the effects of vegetation restoration, specifically the removal of exotic shrubs, on pollination. We analyse 64 plant-pollinator networks and the reproductive performance of the ten most abundant plant species across four restored and four unrestored, disturbed mountaintop communities. Ecosystem restoration resulted in a marked increase in pollinator species, visits to flowers and interaction diversity. Interactions in restored networks were more generalized than in unrestored networks, indicating a higher functional redundancy in restored communities. Shifts in interaction patterns had direct and positive effects on pollination, especially on the relative and total fruit production of native plants. Pollinator limitation was prevalent at unrestored sites only, where the proportion of flowers producing fruit increased with pollinator visitation, approaching the higher levels seen in restored plant communities. Our results show that vegetation restoration can improve pollination, suggesting that the degradation of ecosystem functions is at least partially reversible. The degree of recovery may depend on the state of degradation before restoration intervention and the proximity to pollinator source populations in the surrounding landscape. We demonstrate that network structure is a suitable indicator for pollination quality, highlighting the usefulness of interaction networks in environmental management
Tiptoeing between restoration and invasion: seed rain into natural gaps within a highly invaded relic forest in the Azores
The last remains of native laurel forest in the
Azores are highly threatened by the spread of invasive
plants. Because landslides are very frequent in these
islands, conservation of native laurel forest requires
knowledge of the patterns of bird-dispersed seed rain into
forest gaps. We monitored 78 seed traps over 1 year to
investigate (1) the role of perches in attracting avian dispersers
into gaps, (2) temporal patterns in the dispersal of
exotic and native seeds, (3) how seed rain affects vegetation
establishment in gaps at different distances from the
native forest and (4) whether the caloric content of fruits
could explain the number of seeds dispersed. Perches were
highly effective in concentrating avian seed dispersal.
While some native fruits are produced all year-round, most
exotic plants set fruits during the main peak of the native
fruit production (AugustâNovember). Most seeds recovered
from the traps were native, and native seed rain inside
the native forest was higher than in gaps. However,
deposition of exotic seeds was not affected by distance
from native forest. Seed dispersal frequencies monitored by
seed traps and by faecal analysis were correlated with each
other, but not with fruit caloric content, suggesting that
other factors are more important that the nutritional value
in predicting avian fruit choice. Forest restoration activities
should take into consideration that seed dispersal decreases
sharply beyond 100 m from native forest and the attractive
potential of perches to direct natural seed dispersal into
forest gaps