The impacts of tropical agriculture on biodiversity: a meta-analysis

Biodiversity underpins all food production and strengthens agricultural resilience to crop failure. However, agricultural expansion is the primary driver of biodiversity loss, particularly in the tropics where crop production is increasing and intensifying rapidly to meet a growing global food demand. It is therefore crucial to ask, how do different crops and crop production systems impact biodiversity? Here we show the increasing intensification of tropical agriculture since 1961, along with a sharp rise in harvested area. Using meta-analysis, we find that crop type, rotation time and agricultural intensity, are important determinants of biodiversity assemblages. Perennial tropical crops that are grown in shaded plantations or agroforests (e.g., banana and coffee) support higher alpha-diversity, while those cultivated in unshaded and often homogeneous plantations (e.g., maize, sugarcane, and oil palm) have impoverished biodiversity communities, particularly annual crops. These findings inform our understanding of changes in the ecological contribution of biodiversity to tropical agriculture.

Pesticides and pesticide-related products in ambient air in Germany

Background Tree bark measurements conducted between 2014 and 2017 in a biosphere reserve in Germany have indicated the presence of pesticides from conventional agriculture in ambient air. In the present study, we quantified pesticides and related substances in ambient air at 69 sites using passive air samplers and ventilation filter mats. It is, to our knowledge, so far the most comprehensive data set on pesticides and their related products in ambient air in Germany. Results Samples were collected in 2019 and analysed for over 500 substances. One hundred and nine (109) were detected, including 28 that are not approved for use in Germany. In each sampling site, we identified one to 36 substances, including locations such as national parks and forests. Here, the presence of pesticides is not expected, e.g., on the highest mountain top in the national park “Harz” (13 substances) and in the "Bavarian Forest" (six substances). Glyphosate was recorded in every sample. More than half of passive air samplers contained chlorothalonil, metolachlor, pendimethalin, terbuthylazine, prothioconazole-desthio, dimethenamid, prosulfocarb, flufenacet, tebuconazole, aclonifen, chlorflurenol, hexachlorobenzene (HCB), and γ-hexachlorocyclohexane (γ-HCH). Filter mats also contained boscalid. The statistical analysis showed that landscape classification and agricultural intensity were the primary factors influencing the number of substances detected in ambient air. Location, such as protected areas or regions of organic farming, had only a small effect on the number of substances recorded. Medium- and long-range transport likely accounts for these findings. Extending the current sampling method will probably detect more pesticides than the data currently suggest. Conclusions Airborne pesticide mixtures are ubiquitous in Germany, which is particularly concerning for glyphosate, pendimethalin, and prosulfocarb. Deposition of these pesticides on organic products may disqualify them from the market, resulting in economic losses to farmers. Air concentrations of pesticides are a relevant issue and must be reduced.

Hydrochemistry and Evolution of Water Quality in a Context of Aridity and Increasing Agriculture in Three River Sub-Basins of Santiago Island (Cape Verde)

In regions under development and facing recurrent droughts, increasing the area of irrigated agriculture may create additional disruption in water resources management. The present study was focused on three river sub-basins with the highest agricultural intensity (S. Miguel, Ribeira Seca and S. Domingos) in Santiago Island (Cape Verde). Sets of wells were selected to evaluate the influence of salinization and agriculture practices on the hydrochemistry. This assessment was performed by using data from the bibliography (2003) and a recent campaign (2016). The water chemistry indicates lower mineralization in the S. Miguel sub-basin. Nitrates and nitrites, typically associated with diffuse pollution, are present in all sub-basins, but with varying patterns. Additionally, sodium chloride waters occur in all the three sub-basins, especially those closest to the coastline. In turn, a bicarbonate-magnesium facies was identified in S. Domingos, at the furthest point from the coast, indicating a geological control. The comparison between the two periods suggests a decrease in water quality. The rising extension of the irrigation area associated with aridity should intensify the already observed soil salinization. Thus, the present review highlights the strategic importance of water monitoring at the basin level as a management tool for resources preservation in insular arid and developing regions.

How effective are frogs in regulating crop pest population in a natural multi-trophic system??

Potential of frogs as important natural pest control agents has been highlighted earlier. But the effectiveness of frogs in regulating the pest load in intensive agricultural landscape in a multi-trophic system is not clear. We performed controlled field experiment in paddy field with a varying density (observed in high and low agricultural intensity (AI) areas) of a commonly found frog species and compared the pest and pest predator build-up. The consumption rate of the model amphibian was studied using enclosure experiment. The consequent trophic cascade effect of frogs on both crop pest and other arthropod pest predator was analyzed using mathematical population growth models. Although frogs consumed pests, they could not reduce crop pest abundance. Although a lesser frog density found in high AI areas significantly affected the pest predator abundance. Based on the functional response result, mathematical growth models demonstrated that with a constant harvesting factor (Holling Type II) frogs will always have a negative impact on the beneficial natural enemy population due to intraguild predation thereby limiting its potential as a pest regulator. Our study challenges the notion of frogs as an effective pest control agent and argues that increasing habitat diversity might improve overall biological pest suppression.

Pesticides and Pesticide-Related Products in Ambient Air in Germany

BackgroundTree bark measurements conducted between 2014 and 2017 in a biosphere reserve have indicated the presence of pesticides from conventional agriculture in ambient air in Germany. In the present study, we quantified pesticides and related substances in ambient air at 69 sites using passive air samplers and ventilation filter mats. It is, to our knowledge, so far the most comprehensive dataset on pesticides and their related products in ambient air in Germany. ResultsSamples were collected in 2019 and analysed for over 500 substances, of which 109 were detected, including 28 that are not approved for use in Germany. In each sampling site, we detected one to 36 substances, including at locations such as national parks and forests, where the presence of pesticides is not expected, e.g., on the highest mountain top in the national park “Harz” (13 substances) and in the "Bavarian Forest" (six substances). Glyphosate was detected in every sample. More than half of passive air samplers contained chlorothalonil, metolachlor, pendimethalin, terbuthylazine, prothioconazole-desthio, dimethenamid, prosulfocarb, flufenacet, tebuconazole, aclonifen, chlorflurenol, hexachlorobenzene (HCB), and γ-hexachlorocyclohexane (ɣ-HCH). Filter mats also contained boscalid. The statistical analysis showed that landscape classification and agricultural intensity were the primary factors influencing the number of substances detected in ambient air. Location, such as protected areas or regions of organic farming, had only a small effect on the number of substances recorded. Long-range transport likely accounts for the findings and active sampling of ambient air will probably detect more pesticides and higher concentrations than passive air sampler data presently suggest. ConclusionsAirborne pesticide mixtures are ubiquitous in Germany, which is particularly concerning for glyphosate, pendimethalin, and prosulfocarb. Deposition of these pesticides on organic products may disqualify them from the market, resulting in economic damage to farmers. Air concentrations of pesticides are a relevant issue and must be reduced.

Agri-Environmental Sustainability of Indian Agriculture: A State Level Analysis

Improving economic viability of Indian agriculture is contingent upon agri-environmental sustainability (AES). Objective assessment of environmental costs of agriculture is lacking in India. Unless internalise environmental impacts of agriculture will be borne by the society at large, in terms of depletion and degradation of water resources, land degradation and emissions of greenhouse gases, etc. To assess AES of Indian agriculture, the present article builds a comprehensive agri-environmental sustainability index (AESI) based on 40 agri-environmental indicators. The study captures both spatial and temporal aspects of AES by covering 17 major Indian states over 24 years (1990–1991 to 2013–2014). The estimated AESI scores are validated with outcome indicators (e.g., groundwater depletion, depletion of soil nutrients). The results show that states having higher score in Sustainable Irrigation Index are facing lower fall in groundwater level and there are negative correlations across sub-indices of AESI and macronutrient deficiencies in soil. An inverse relationship between AESI scores and agricultural intensity (as measured by average productivity of foodgrains in kilograms per hectare) is also observed. The study comes out with policy suggestions which could help to attain AES of Indian agriculture.

The response of groundwater to multiple concerning drivers and its future: a study on Birbhum District, West Bengal, India

Groundwater and its upcoming crisis are the present-day concern of the scientist. This research mainly focuses on responses of groundwater dynamicity to some important drivers, viz. agricultural yield, groundwater irrigated area, groundwater draft, landuse/landcover, and stage of development. The result of this study has been done under three sections. In the first section, the spatiality of groundwater has been discussed where it has been noticed that the western side of the district groundwater level is near the surface due to low drafting and low agricultural yield. Moreover, hard rock geology in the western part disappoints the drilling process. On the eastern part, rich alluvial soil influences high agricultural yield hence groundwater level lowering down rapidly. In the second section, the nature of groundwater levels has been analyzed through the boxplot, and cluster diagram, where boxplots have been drawn over different geological facies, which depicts groundwater is highly fluctuating in hard clay geology. For example, high agricultural intensity and high groundwater draft is the characteristic feature of hard clay geology. The dendrogram in cluster analysis represents a homogeneous groundwater level fluctuating station in three different time series. Last section deals with the future of groundwater level where an artificial neural network (ANN) model has been applied to extract the predicted groundwater level for 2030. This type of environmental analysis, such as groundwater fluctuations in relation to different sensitive parameters and the use of a machine learning model, would aid potential researchers and communities in making wise groundwater use decisions.

From Global to Local

The Autonomous Region of Bougainville, Papua New Guinea, conducted an independence referendum in 2019, which resulted in the region seeking a pathway to complete independence. One of the requirements in establishing independence is ensuring “good governance,” an important facet of which is establishing a stable and adequate food supply. This is framed globally as achieving Sustainable Development Goal Two (SDG #2) to end hunger and malnutrition. This article seeks to assess the measures that government and major donors have taken to implement SDG #2 in Bougainville using a pressure-state-response framework and desktop-based risk assessment to identify areas for further work. The investigation aims to identify effective policy focus areas in order to better implement SDG #2, namely, prioritising civil conflict avoidance, facilitating adaptation planning for climate regime shifts, and ensuring sustainable agricultural intensity and fisheries extraction. Based on these, recommendations for good governance include sustainable and equitable long-term interventions that reduce the risk of political disturbance and environmental degradation. As a result of engaging in this case, readers will be able to apply similar methodologies to inform development decisions in postconflict contexts. Bougainville faces similar challenges to many Pacific islands, including the impacts from climate change, food insecurity, conflict, population growth, and changing land tenure. This case can be extrapolated to these greater contexts.