Presseinformation: Bats as a form of biological pest control

Nr. 107 - 24.08.2026

Researchers investigate impact of near-natural habitats on macadamia nut production

Labour-intensive harvesting, complex processing: the macadamia is one of the most expensive nuts in the world. This makes it all the more important to protect the trees from pests. An international research team led by the University of Göttingen has now investigated how natural vegetation in and around macadamia plantations affects pest infestation, paying particular attention to bird and bat populations. The researchers were able to demonstrate that the higher the level of bat activity, the lower the incidence of pest infestation. At the same time, yields increased in landscapes with a higher proportion of natural vegetation. The findings were published in the journal Agriculture, Ecosystems and Environment.

The team studied ten intensively managed macadamia plantations in South Africa. At each site, the researchers compared trees at the edge of the plantation with those in the centre in order to analyse the influence of the surrounding vegetation. They recorded 111 bird species through observation and 16 bat species via their echolocation calls. Bat activity reduced insect damage, particularly in plantations that contained less natural habitat or were surrounded by it. Natural habitat in this context includes, for example, native forests, bushland or scrubland. In contrast, so-called exclusion trials showed a significant effect on nut quality: When birds and bats were kept away from the trees by nets, the proportion of nuts damaged by insects rose from 6.2 to 10.7 per cent – an increase of around 70 per cent. However, no direct influence of bird numbers on pest infestation could be demonstrated.

Not only did the number of bats increase as the proportion of natural habitats rose, but so did their diversity. Even the yield from the macadamia trees was linked to this proportion, reaching its highest level when natural habitats accounted for around 60 per cent. At the same time, bird communities differed between the edges and the centre of the plantations: species that prefer dense vegetation and woody vegetation were more common at the edges, whilst species of open habitats predominated in the centre.

“Natural habitats are valuable refuges and support beneficial organisms that provide pollination and pest control, which in turn is good for agricultural production and for farmers. It is therefore essential that natural habitats and their conservation are incorporated into the planning of agricultural land,” explains lead author Dr Mina Anders from the Department of Functional Agrobiodiversity and Agroecology at the University of Göttingen. The study highlights the importance of natural habitats for a form of agriculture that combines biodiversity with agricultural production.

Original publication: Anders, M. et al. Landscape characteristics influence pest control services in macadamia orchards and shape bird and bat assemblages. Agriculture, Ecosystems and Environment (2026). DOI: https://doi.org/10.1016/j.agee.2026.110666

Contact:
Dr Mina Anders

University of Göttingen

Fakulty of Agricultural Sciences

Agroecology and Functional Agrobiodiversity Group

Grisebachstraße 6, 37077 Göttingen

Phone: +49 551 39-28265

Email: mina.anders@uni-goettingen.de

Internet: www.uni-goettingen.de/en/602959.html