Climate-Smart Agriculture and Trade-Offs With Biodiversity and Crop Yield

Abstract

Biophysical evaluations of climate-smart agriculture (CSA) often overlook the potential interactions with and implications for biodiversity and ecosystem services, which are important determinants of food system resilience and sustainability. Drawing on a case study in the East Usambara Mountains, Tanzania, we compare the impacts of CSA with other agricultural management practices on invertebrate pest and natural enemy diversity, and the associated effects on crop damage and crop yield. We found that the most common CSA practices in the region, terracing and trenching with live and compost mulches, provided the best outcomes for crop production, pest suppression and agricultural income. However, greater diversity of pests was observed when neighboring fields planted improved crop varieties, suggesting that the use of improved varieties by farmers creates increased vulnerability to pest damage among neighboring farmers that used local varieties. Also, greater natural enemy diversity was found when neighboring fields were either intercropped or left fallow highlighting spatial flows of ecosystem services between fields. Landcover heterogeneity was positively correlated with pest diversity, whilst landcover richness was positively associated with higher pest volume, highlighting the importance of landscape characteristics in pest and natural enemy dynamics. Finally, we found that crop damage was most severe when pest communities had low species richness, suggesting that a small number of key crop pests contribute to most yield losses. Our findings illustrate that those varied combinations of agricultural management practices lead to heterogeneous biodiversity outcomes and trade-offs, and highlight the importance of local management, neighborhood effects and landscape characteristics. CSA evaluations must therefore look beyond productivity as a measure for success, as trade-offs with invertebrate biodiversity, food production, and environmental sustainability often interact and feedback in complex and unexpected ways.

Advances in Quercus ilex L. breeding: the CRISPR/Cas9 technology via ribonucleoproteins

“…The disease is mainly caused by the oomycete P. cinnamomi but other pathogens and global climate change also contribute to accelerate the damages provoked by the oomycete. Currently, the use of disease-tolerant plants is considered an efficient and cost-effective alternative for managing plant diseases ( Tripathi et al., 2022 ). In woody species, yet, long periods are necessary to apply for conventional breeding programs ( Corredoira et al., 2016 ).…”

Biological control interventions reduce pest abundance and crop damage while maintaining natural enemies: a meta-analysis

“…A key avenue for future research would involve large scale studies to identify clear patterns in the relationship between landscape complexity and natural enemy activity and the ecosystem service delivered to sub-Saharan agricultural systems. Furthermore, recent evidence from SSA showed that natural enemy diversity in crop fields is dependent on the land management of neighbouring fields (Tripathi et al 2022). This highlights the need for further multi-scale studies to identify potential variation in biocontrol effectiveness across different land management contexts.…”

“…Biocontrol techniques have been applied to numerous crops and targeted a wide variety of pests in the region, yet there is a lack of understanding of how the effectiveness of biocontrol varies across different crop types and pest taxa (Ratto et al2022). Recent research in Tanzania found greater natural enemy diversity in fields surrounded by intercropped fields, suggesting spatial flow of potential biocontrol services across landscapes (Tripathi et al 2022), but the established relationship between landscape composition, natural enemies and pest regulation is almost entirely based on studies carried out in the global north, and very seldom in sub-Saharan regions where farmers are most exposed to food insecurity caused by crop pests (Steward et al 2014). This represents a key knowledge gap; more clarity is needed about the environmental factors affecting biocontrol performance in sub-Saharan Africa to better assist in smallholder farmer decision making, and to determine the broader indirect impact of pest management options on biodiversity compared to synthetic pesticides, both on a farm and at a landscape scale.…”

Biological control interventions reduce pest abundance and crop damage while maintaining natural enemies in sub-Saharan Africa: a meta-analysis

“…A key avenue for future research would involve large scale studies to identify clear patterns in the relationship between landscape complexity and natural enemy activity and the ecosystem service delivered to sub-Saharan agricultural systems. Additionally, recent evidence from SSA showed that natural enemy diversity in crop fields is dependent on the land management of neighbouring fields [29]. This highlights the need for further multi-scale studies to identify potential variation in biocontrol effectiveness across different land management contexts.…”

“…Biocontrol techniques have been applied to numerous crops and targeted a wide variety of pests in the region, yet there is a lack of understanding of how the effectiveness of biocontrol varies across different crop types and pest taxa [28]. Recent research in Tanzania found greater natural enemy diversity in fields surrounded by intercropped fields, suggesting spatial flow of potential biocontrol services across landscapes [29]. However, the established relationship between landscape configuration, natural enemies and pest regulation is almost entirely based on studies carried out in the global north and some global south regions [30], but very seldom in sub-Saharan regions where farmers are most exposed to food insecurity caused by crop pests [31].…”