Abstract Agricultural landscapes are constantly changing as farmers adopt new production practices and respond to changing environmental conditions. Some of these changes alter landscape structure with impacts on natural pest control, pesticide use, and conservation of biodiversity. In rice agroecosystems the effect of landscape structure on natural enemies and pest suppression is often poorly understood. Here we investigate the effect of landscape composition and configuration on a key pest of rice, the brown planthopper ( Nilaparvata lugens ). Using N. lugens as sentinel prey coupled with predator exclusions, we investigated landscape effects on herbivore suppression and rice grain yield at multiple spatial scales in two regions of Bangladesh. Ladybird beetles and spiders were the most abundant natural enemies of N. lugens with landscape effects observed at all scales on ladybird beetles. Specifically, ladybird beetles were positively influenced by road edges, and fallow land, while spiders were strongly influenced only by rice phenology. Predator exclusion cages showed that N. lugens abundance significantly increased in caged plots, reducing rice gain yield. We also used an estimated biocontrol service index that showed a significant positive relationship with landscape diversity and a significant negative impact on pest density and yield loss. These results suggest that promoting fallow lands and fragmented patches between rice fields could lead to more sustainable insect pest management in rice agroecosystems, potentially reducing the practice of prophylactic insecticide use.
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Landscape diversity influences the arthropod species diversity in the rice field
Landscape diversity is one of the key drivers for maintaining ecosystem services in agricultural production by providing vital habitats and alternative food sources for beneficial insects and pollinators within the agricultural landscapes. The landscape structure, land uses, and diversity differ between geographic locations. However, how the changes of landscape structure and land use diversity affect the arthropod diversity in a geographic area is poorly understood. Here, we tested the impact of landscape diversity on the rice locations in Bangladesh. Results ranged from highly diversified to very highly diversified in Chattogram (>7.9), to highly diversified (0.590.79) in Satkhira and moderately (0.390.59) to less diversified (0.190.39) in Patuakhali. These significant different landscape diversities influenced the arthropod diversity in rice fields. Arthropod species diversity increases with the increase in the Land Use Mix (LUM) index. The maximum tillering stage of rice growth harbored higher abundance and species diversity in rice fields. Moreover, we found that vegetation is the most important factor influencing the abundance of arthropods. Extensive agriculture and forest contributed substantially to predicting arthropod richness. Meanwhile, barren land and high-density residential land as well as intensive agriculture had large impact on species diversity. This study indicates that landscape diversity plays a vital role in shaping the species diversity in rice fields, providing guidelines for the conservation of arthropod diversity, maximizing natural pest control ecosystem service and more secure crop production itself.
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- Award ID(s):
- 1832042
- NSF-PAR ID:
- 10409301
- Date Published:
- Journal Name:
- Frontiers in Environmental Science
- Volume:
- 10
- ISSN:
- 2296-665X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract As demand for wood products increases in step with global population growth, balancing the potentially competing values of biodiversity conservation, carbon storage and timber production is a major challenge. Land sparing involves conserving forest while growing timber in intensively managed areas. On the other hand, land sharing utilizes ecological forestry approaches, but with a larger management footprint due to lower yields. While the sparing‐sharing framework has been widely tested and debated in agricultural settings to balance competing values, such land‐allocation strategies have been rarely studied in forestry.
We examined whether a sparing, sharing or Triad strategy best achieves multiple forest objectives simultaneously. In Triad, management units (stands) in forest landscapes are allocated to one of three treatments: reserve (where conservation is the sole objective), intensive (timber production is the sole objective) and ecological (both objectives are combined). To our knowledge, ours is the first Triad study from the temperate zone to quantify direct measures of biodiversity (e.g. species' abundance).
Using a commonly utilized forest planning tool parameterized with empirical data, we modelled the capacity of a temperate rainforest to provide multiple ecosystem services (biodiversity, carbon storage, timber production and old‐growth forest structure) over 125 years based on 43 different allocation scenarios. We then quantified trade‐offs between scenarios, taking into account the landscape structure, and determined which strategies most consistently balanced ecosystem services.
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Synthesis and applications . We found that maximizing multiple elements of biodiversity and ecosystem services simultaneously with a single management strategy was elusive. The strategy that maximized each service and species varied greatly by both the service and the level of timber production. Fortunately, a diversity of management options can produce the same wood supply, providing ample decision space for establishing priorities and evaluating trade‐offs. -
Human land use threatens global biodiversity and compromises multiple ecosystem functions critical to food production. Whether crop yield–related ecosystem services can be maintained by a few dominant species or rely on high richness remains unclear. Using a global database from 89 studies (with 1475 locations), we partition the relative importance of species richness, abundance, and dominance for pollination; biological pest control; and final yields in the context of ongoing land-use change. Pollinator and enemy richness directly supported ecosystem services in addition to and independent of abundance and dominance. Up to 50% of the negative effects of landscape simplification on ecosystem services was due to richness losses of service-providing organisms, with negative consequences for crop yields. Maintaining the biodiversity of ecosystem service providers is therefore vital to sustain the flow of key agroecosystem benefits to society.more » « less
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Synthesis and applications . Our results show positive effects of native forests on biodiversity and yield in soybean crops, highlighting the need for conservation of forest fragments in agricultural landscapes. Moreover, the relation between natural enemies and crop yield suggests that Chaco forests support a diverse and abundant community of natural enemies that can provide sustained levels of ecosystem services and result in positive effects for farmers.
- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3389/fenvs.2022.740287
