Insect community composition and functional roles along a tropical agricultural production gradient

Angelina Sanderson Bellamy,Michael Tedengren,Jonas Gunnarsson,Paul J Van Den Brink,Ola Svensson

doi:10.1007/s11356-018-1818-4

Abstract

High intensity agricultural production systems are problematic not only for human health and the surrounding environment, but can threaten the provision of ecosystem services on which farm productivity depends. This research investigates the effects of management practices in Costa Rica on on-farm insect diversity, using three different types of banana farm management systems: high-input conventional system, low-input conventional system, and organic system. Insect sampling was done using pitfall and yellow bowl traps, left for a 24-h period at two locations inside the banana farm, at the edge of the farm, and in adjacent forest. All 39,091 individual insects were classified to family level and then morphospecies. Insect species community composition and diversity were compared using multivariate statistics with ordination analysis and Monte Carlo permutation testing, and revealed that each of the management systems were significantly different from each other for both trap types. Insect diversity decreased as management intensity increased. Reduced insect diversity resulted in fewer functional groups and fewer insect families assuming different functions essential to ecosystem health. Organic farms had similar species composition on the farm compared to adjacent forest sites, whereas species composition increasingly differed between farm and forest sites as management intensity increased. We conclude that while organic production has minimal impact on insect biodiversity, even small reductions in management intensity can have a significantly positive impact on on-farm insect biodiversity and functional roles supported.

Highlights

Agricultural systems depend on ecosystem services, including but not limited to, pollination, pest control, nutrient cycling, Responsible editor: Philippe GarriguesBy 2001, there was a consensus that many species are needed to maintain stability of ecosystem functioning, in the face of environmental changes (Loreau et al 2001)
The results of this study show that the greater the intensity of management practices in banana production, the greater the effect in reducing diversity of insect populations on banana farms
As research in this area still remains largely theoretical, there is a need for research that can quantify the relationship between insect biodiversity and provisioning of ecosystem services, for example the extent to which biodiversity may be lost before it affects the provision of ecosystem services

Summary

Introduction

Agricultural systems depend on ecosystem services, including but not limited to, pollination, pest control, nutrient cycling, Responsible editor: Philippe GarriguesBy 2001, there was a consensus that many species are needed to maintain stability of ecosystem functioning, in the face of environmental changes (Loreau et al 2001). Agricultural systems depend on ecosystem services, including but not limited to, pollination, pest control, nutrient cycling, Responsible editor: Philippe Garrigues. Research shows that higher diversity leads to functional complementarity which increases productivity and nutrient retention; some ecosystem processes are unaffected by initial. Insect diversity was partitioned into functional roles and used as an indicator of the depth of provisioning of on-farm ecosystem services. The functional roles studied include recycling/detrivore, fungivore, predator, herbivorous, scavenger, parasitoids, and ants which fulfill multiple functions simultaneously. Diversity of insects and other arthropods (arachnids and acarina) was chosen as the measure of environmental quality in this study because they comprise 90% of the organismal variability of all species. Some services that insects provide are decomposition of organic matter and recycling nutrients, conditioning of soil by channeling and moving material to different soil layers, and predation on pest insects. Of all of the insects that have been identified, less than 1% of those are pests

Methods

Results

Discussion

Conclusion