科学家说，蜜蜂促进了巴西的森林修复。

[SÃO PAULO] Some of the most important tree species for the restoration and conservation of tropical forests rely heavily on bees as transporters of pollen.

Bees facilitate pollination over great distances, increase the genetic diversity of plants, and stimulate the reproduction and resilience of native species in degraded ecosystems.

That’s why conserving these declining insects should be a priority in forest restoration projects, according to a study by Brazilian scientists published inEcological Applications。

“Restoration programmes have the power to bring back bee populations, just as bees may stimulate the reproduction and resilience of native species in degraded ecosystems,”

Ricardo Ribeiro Rodrigues, College of Agriculture, University of São Paulo

The study analysed how different bee species responded to changes in Brazilian forest landscapes. It investigated how increasing bee populations may boost pollen dispersal when planting trees in restoration projects, and also help re-establish diverse forests in disturbed areas in Brazil.

Researchers carried out fieldwork in an agricultural area of the Atlantic Forest in the country’s south-east, which had been turned into sugarcane fields. Only about seven per cent of the original vegetation remains there, in small fragments of primary forest comprised of discontinuous canopies covered by vines and bordered by invasive grasses.

The team also included two other less degraded areas as reference ecosystems. One of these contained contained highly diverse trees reintroduced by researchers about two decades ago to increase forest cover, while the other consisted of wetlands, dominated by herbaceous vegetation.

In each of these landscapes, researchers installed “pan traps” — a standard method for capturing bees — with the aim of collecting insect samples at the peak of the flowering season, between October 2015 and January 2017.

They compared the abundance and diversity of bee populations in each habitat and analysed the pollen grains stuck to their bodies to determine which plant species the insects had interacted with.

The team collected 727 bees of 85 species, with different sizes and flight skills, social behaviour, nesting sites and diets, and found that these had interacted with 220 different plant species.

蜜蜂的丰富度对栖息地的变化产生了负面的反应，在高度干扰的环境中减少了（例如人为湿地和甘蔗田）。beplay足球体育的微博但是，在恢复森林以及原始森林碎片的地区，它们的数量有所增加，那里的大型和中型物种在地上筑巢是占主导地位的。

Small and medium-sized bee species that nest underground, with varying levels of social behaviour and diet, were unaffected by habitat change, and even tended to increase in some disturbed areas, researchers said.

Meanwhile, ‘oligolectic’ bees — which typically prefer pollen from a single genus of flowering plants — responded negatively to habitat change.

Ricardo Ribeiro Rodrigues是圣保罗大学Luiz de Queiroz农业学院的生物学家，他专门从事森林恢复，并由该研究合着。beplay下载官网西西软件他说，结果表明：“恢复计划有能力带回蜜蜂种群，就像蜜蜂可能刺激降解生态系统中本地物种的繁殖和韧性一样”。

“It is a system that positively feeds back,” he added. “So bee conservation should be prioritised in restoration programmes through the reintroduction of nesting materials in cases of locally extinct species.”He explained that bees will return in time as trees get bigger and older, providing new nesting sites and other plant substrates for their reproduction.

Vera Lúcia Imperatriz-Fonseca, a biologist at the University of São Paulo’s Biosciences Institute, said: “Brazil is rich in species of pollinators such as bees, but we urgently need a more solid public policy that guarantees their conservation, as countries like the United States, United Kingdom, France and Norway are doing. Taking care of pollinators is a sure return for biodiversity.”

With bees disappearing in many regions of the world, the causes and consequences of this loss are already being analysed to find solutions, said Imperatriz-Fonseca.

“The results presented in the study may help guide public policy actions for restoring forest areas that include bees in their strategy,” she added.

This article was produced by SciDev.Net’s Latin America & Caribbean desk.

Thestudypublished in Ecological Applications was supported by FAPESP, a donor of SciDev.Net.