Dataset from: The effects of crop type, landscape composition and agroecological practices on biodiversity and ecosystem services in tropical smallholder farms

1. In the tropics, smallholder farming characterizes some of the world’s
most biodiverse landscapes. Agroecology as a pathway to sustainable
agriculture has been proposed and implemented in sub-Saharan Africa, but
the effects of agricultural practices in smallholder agriculture on
biodiversity and ecosystem services are understudied. Similarly, the
contribution of different landscape elements, such as shrubland or
grassland cover, on biodiversity and ecosystem services to fields remains
unknown. 2. We selected 24 villages situated in landscapes with varying
shrubland and grassland cover in Malawi. In each village, we assessed
biodiversity of eight taxa and ecosystem services in relation to crop
type, shrubland and grassland cover and the number of agroecological pest
and soil management practices on smallholder’s fields of different crop
types (bean monoculture, maize-bean intercrop, and maize monoculture). 3.
Increasing shrubland cover altered carabid and soil bacteria communities.
Carabid abundance increased in maize but decreased in intercrop and bean
fields with increasing shrubland cover. Carabid abundance and richness and
wasp abundance increased with soil management practices. Carabid, spider,
and parasitoid abundances were higher in bean monocultures, but this was
modulated by surrounding shrubland cover. Natural enemy abundances in
beans were especially high in landscapes with little shrubland, possibly
leading to lower bean damage in monocultures compared to intercropped
fields, whereas maize monocultures had higher damage. In maize, grassland
cover and pest management practices were positively related to damage.
Carabid abundance was higher in fields with high bean damage and increased
carabid richness in fields with high maize damage. Parasitoid abundance
was negatively associated with bean damage. 4. Synthesis and application:
Our results suggest that maintaining biodiversity and ecosystem services
on smallholder farms is not achievable with a “one size fits all” approach
but should instead be adapted to the landscape context and the priorities
of smallholders. Shrubland is important to maintain carabid and soil
bacterial diversity, but legume cultivation beneficial to natural enemies
could complement pest management in landscapes with a low shrubland cover.
An increased number of agroecological soil management practices can lead
to improved pest control whilst the effectiveness of agroecological pest
management practices needs to be re-evaluated.