Ingo Grass

University of Hohenheim · Ecology of Tropical Agricultural Systems

Terrestrial animal biodiversity is increasingly being lost because of land-use change1,2. However, functional and energetic consequences aboveground and belowground and across trophic levels in megadiverse tropical ecosystems remain largely unknown. To fill this gap, we assessed changes in energy fluxes across ‘green’ aboveground (canopy arthropods...

Agricultural simplification continues to expand at the expense of more diverse forms of agriculture. This simplification, for example, in the form of intensively managed monocultures, poses a risk to keeping the world within safe and just Earth system boundaries. Here, we estimated how agricultural diversification simultaneously affects social and...

The expansion of the oil palm industry in Indonesia has improved livelihoods in rural communities, but comes at the cost of biodiversity and ecosystem degradation. Here, we investigated ways to balance ecological and economic outcomes of oil palm cultivation. We compared a wide range of production systems, including smallholder plantations, industr...

The continuing biodiversity losses through agricultural expansion and intensification are dramatic. We argue that a mix of on- and off-field measures is needed, overcoming the false dichotomy of the land sharing-sparing debate. Protected land is essential for global biodiversity, while spillover between farmed and natural land is key to reducing sp...

In many crops, both pollination and biocontrol determine crop yield, whereby the relative importance of the two ecosystem services can be moderated by the landscape context. However, additive and interactive effects of pollination and biocontrol in different landscape contexts are still poorly understood. We examined both ecosystem services in Sout...

More than half of all life on Earth lives belowground and regulates a wide range of ecosystem functions via their diverse trophic interactions. However, information on how trophic diversity of soil animals varies across functional groups and major environmental gradients is lacking. Here, we use stable isotope analysis (13C/12C and 15N/14N ratios)...

Organic agriculture and agroforestry are two agroecological approaches that have been proposed to address the many negative externalities of intensive agriculture.However, their comparative efficiency in promoting sustainability when combined is unclear, as they are typically studied in isolation. To address this we conducted a systematic review of...

Identifying landscapes that are suitable for both biodiversity conservation and agricultural production is a major challenge. Traditionally, much research has focused on biodiversity conservation outside of agricultural production areas, e.g., in semi-natural habitats. In contrast, recent research has mainly focused on the potential of crop heterog...

Transformation of forests into agricultural lands threatens biodiversity and ecosystem functions globally. In the biodiversity hotspot Madagascar, key ecosystem functions along with highly endemic flora and fauna are under threat. Comprehensive studies identifying determinants of biodiversity and ecosystem functions losses are lacking, with no stud...

Understanding the organization of mutualistic networks at multiple spatial scales is key to ensure biological conservation and functionality in human-modified ecosystems. Yet, how changing habitat and landscape features affect pollen–bee interaction networks is still poorly understood. Here, we analysed how bee–flower visitation and bee–pollen-tran...

In Indonesia, the rapid expansion of oil palm and rubber plantations replaces large areas of tropical rainforest. Rainforest transformation alters the diversity and composition of parasitoid wasp communities, but appropriate management strategies to buffer their decline in rainforest transformation landscapes are not yet developed. Here, we studied...

Exotic plant invasions threaten biodiversity and are costly to farmers. Land use is a major pathway promoting the spread of exotic plant species; however, little is known about the processes underlying the success of exotic plants in tropical agricultural landscapes. Focussing on the heterogeneous smallholder landscapes of north‐eastern Madagascar,...

Although pesticides are seen as one of the main drivers of insect decline, there are still only few studies that assess their effects on non-target species under field conditions. Here we investigated the effects of the neonicotinoid insecticide Mospilan(R)SG (active ingredient acetamiprid) on plant bugs (Heteroptera: Miridae), a dominant group of...

Hybrid intelligence - arising from the sensible, targeted fusion of human minds and cutting-edge computational systems-holds great potential for enhancing the sustainability of agriculture. Leveraging the combined strengths of both collective human and artificial intelligence helps identify and stress-test pathways towards the reconciliation of bio...

This data includes: 1) Understorey plant communities across 70 plots with their species names, genus, family, and species origin (native, exotic or unknown origin), number of individuals and species cover per plot, assessed using 8 subplots of 4 m² per plot and then pooled on plot level. 2) Plot characteristics (plot code, land-use history, canop...

In tropical regions, shifting from forests and traditional agroforestry to intensive plantations generates conflicts between human welfare (farmers’ demands and societal needs) and environmental protection. Achieving sustainability in this transformation will inevitably involve trade-offs between multiple ecological and socioeconomic functions. To...

Now published as a paper: https://doi.org/10.1016/j.gecco.2024.e03154 Transformation of forests into agricultural lands threatens biodiversity and ecosystem functions globally. In the biodiversity hotspot Madagascar, key ecosystem functions along with highly endemic flora and fauna are under threat. Comprehensive studies identifying proximate driv...

South Africa is the World’s largest producers of macadamia nuts, with about 51,000 ha of land covered by macadamia. This leads to major farming challenges, as the expansion of orchards is associated with the loss of habitat and biodiversity, the excessive use of and resistance to insecticides, and an increased pressure on water resources. More freq...

Governments across the Global South invest heavily in agricultural development to combat poverty and hunger. But while crucial for improving the livelihoods of millions, agricultural development can undermine biodiversity. Our authors explain how these issues relate to one another and demonstrate why reconciling agricultural production and biodiver...

Urbanization is a major driver of biodiversity change but how it interacts with spatial and temporal gradients to influence the dynamics of plant–pollinator networks is poorly understood, especially in tropical urbanization hotspots. Here, we analysed the drivers of environmental, spatial and temporal turnover of plant–pollinator interactions (inte...

The expansion of homogeneous landscapes has been a major driver of biodiversity loss, climate change and land degradation. There is an urgent need for a transition to multifunctional landscapes that provide abundant and nutritious food while also delivering several other contributions essential for a good quality of life. However, implementing this...

Habitat changes can alter animal behaviors, especially of large-bodied animals. Landfowl (Galliformes) are a phylogenetically diverse group of large-bodied ground-dwelling birds that are generally considered reluctant flyers. However, some species of landfowl have also been found to forage in arboreal habitats, which could be particularly advantage...

Habitat loss is a primary driver of biodiversity decline, but differences in species responses to habitat loss from local to landscape scales are poorly understood. Trophic level, food and habitat specialization have been suggested to be important predictors of species responses to habitat loss, landscape diversity and landscape scale. Using cavity...

Worldwide, urban areas are spreading at massive rates. Simultaneously, urban agriculture is growing in importance. However, urbanization effects on functional biodiversity on farmland remain poorly studied, especially in urbanization hotspots of the global south. Here, we sampled birds on 36 farms across three seasons (one full year) and along two...

https://www.currentconservation.org/addressing-agricultural-labour-issues-is-key-to-biodiversity-smart-farming/

Enhancing biodiversity in monoculture-dominated landscapes is a pressing restoration challenge. Planted tree islands can enhance biodiversity locally, but the role of processes at larger spatial scales is unclear. Using a multi-scale approach, we explored how these scale-dependent processes influence the diversity of seven taxa (woody plants, under...

Tropical lowland rainforest conversion leads to decreases diversity and population in insect pollinators, including stingless bees. However, how stingless bees respond to this conversion is still being studied. In this study we observed the number of flight activities of the Tetragonula laeviceps (Smith) in three converted land types in Jambi, Suma...

Expanding cities increasingly encroach fertile farmlands, questioning the viability of maintaining agriculture within and around them. Yet, our knowledge on how urbanization influences pollinator communities and the provision of pollination services to crops is limited, especially for the urbanization hotspots of the Global South. Mango Mangifera i...

There is an urgent need for agricultural development strategies that reconcile agricultural production and biodiversity conservation. This is especially true in the Global South where population growth is rapid and much of the world's remaining biodiversity is located. Combining conceptual thoughts with empirical insights from case studies in Indon...

Enhancing biodiversity in monoculture-dominated landscapes is a key sustainability challenge that requires considering the spatial organization of ecological communities (beta diversity). Here, we tested whether increasing landscape heterogeneity, through establishing 52 tree islands in an oil-palm landscape, is a suitable restoration strategy to e...

Tropical agricultural landscapes often consist of a mosaic of different land uses, yet little is known about the spectrum of ecosystem service bundles and materials they provide to rural households. We interviewed 320 households on the different benefits received from prevalent land-use types in northeastern Madagascar (old-growth forests, forest f...

This data includes survey questionnaire and data from the paper "Complementary ecosystem services from multiple land uses highlight the importance of tropical mosaic landscapes"

Following severe forest loss in recent decades, Southeast Asian countries are increasingly employing social forestry as a means to ensure the sustainable development of their forest-dwelling communities. Given the potential of agroforestry to provide multiple ecosystem services, habitat for the maintenance of biodiversity, and the economic and soci...

In the United Nations Decade on Ecosystem Restoration¹, large knowledge gaps persist on how to increase biodiversity and ecosystem functioning in cash crop-dominated tropical landscapes². Here, we present findings from a large-scale, 5-year ecosystem restoration experiment in an oil palm landscape enriched with 52 tree islands, encompassing assessm...

As the extent of oil palm (Elaeis guineensis) cultivation has expanded at the expense of tropical rainforests, enriching conventional large‐scale oil palm plantations with native trees has been proposed as a strategy for restoring biodiversity and ecosystem function. However, how tree enrichment affects insect‐mediated ecosystem functions is unknow...

The global macadamia industry is growing rapidly, and the world's biggest macadamia nut producer, South Africa, is continuously expanding its production. Insect pest mitigation and research are mainly focused on the damage caused by heteropteran pest species, whereas the damage associated with lepidopteran tortricid moths in South African macadamia...

Farming systems that support locally diverse agricultural production and high levels of biodiversity are in rapid decline, despite evidence of their benefits for climate, environmental health, and food security. Yet, agricultural policies, financial incentives, and market concentration increasingly constrain the viability of diversified farming sys...

Climate and insect pests are vital variables that affect crop production. Climate change will alter the magnitude and timing of precipitation, but how rainfall and temperature interact to affect insect pest damage in agriculture is poorly understood. Here, we explore the interacting effects of elevation and contrasting weather conditions (a wet vs....

Oil palm is the most productive oil crop, but its high productivity is associated with conventional management (that is, high fertilization rates and herbicide application), causing deleterious environmental impacts. Using a 2² factorial experiment, we assessed the effects of conventional vs reduced (equal to nutrients removed by fruit harvest) fer...

More sustainable and environmentally friendly agricultural practices, including ecological intensification, are needed to reduce biodiversity loss and environmental degradation. We evaluated the potential of ecological intensification through the enhancement of pollination services in an intensively managed and insect‐pollinated crop, Macadamia int...

Twenty-three years ago, in January 2000, the first issue of Basic and Applied Ecology was published. Over the past 23 years, the journal has undergone major changes, reflecting both the rapid development of ecology and of scientific publication practices.

Habitat fragmentation impacts seed dispersal processes that are important in maintaining biodiversity and ecosystem functioning. However, it is still unclear how habitat fragmentation affects frugivorous interactions due to the lack of high-quality data on plant-frugivore networks. Here we recorded 10,117 plant-frugivore interactions from 22 reserv...

How to enhance biodiversity in monoculture-dominated landscapes is a key sustainability question that requires considering the spatial organization of ecological communities (beta diversity). Here, we experimentally tested if increasing landscape heterogeneity - through tree islands - is a suitable landscape restoration strategy when aiming to enha...

Natural habitat plays a role in many agroecosystems as a source of pollination services and other ecological spillover, but these effects are largely unquantified in oil palm (Elaeis guineensis), a globally important crop linked to deforestation. In a field experiment in Sumatra, Indonesia, we manipulated floral visitor access to female oil palm in...

How urbanization affects crop pollination has scarcely been studied, especially in the tropics. Here, we focus on the richness and abundance of wild bees and their pollination services to 30 small-scale fields of Lablab purpureus, a globally wide-spread grain legume, in the Indian megacity Bangalore. Farms were selected along a gradient of urbaniza...

Urbanization poses a major threat to biodiversity and food security, as expanding cities, especially in the Global South, increasingly compete with natural and agricultural lands. However, the impact of urban expansion on agricultural biodiversity in tropical regions is overlooked. Here we assess how urbanization affects the functional response of...

Resolving ecological-economic trade-offs between biodiversity and yields is a key challenge when addressing the biodiversity crisis in tropical agricultural landscapes. Here, we focused on the relation between seven different taxa (trees, herbaceous plants, birds, amphibians, reptiles, butterflies, and ants) and yields in vanilla agroforests in Mad...

Extreme events, such as those caused by climate change, economic or geopolitical shocks, and pest or disease epidemics, threaten global food security. The complexity of causation, as well as the myriad ways that an event, or a sequence of events, creates cascading and systemic impacts, poses significant challenges to food systems research and polic...

Background Intense conversion of tropical forests into agricultural systems contributes to habitat loss and the decline of ecosystem functions. Plant-pollinator interactions buffer the process of forest fragmentation, ensuring gene flow across isolated patches of forests by pollen transfer. In this study, we identified the composition of pollen gra...

1. The conversion of tropical forests into agriculture reduces biodiversity dramatically. However, species might differ in their responses, depending on their habitat specialisation and geographic origin. In this study, we assess how butterfly assemblages differ between old-growth forests, forest fragments, forest-derived vanilla agroforests, fallo...

Conventional agriculture in the global north is typically characterized by large monocultures, commonly managed with high levels of pesticide or fertilizer input and mechanization. Strip intercropping, that is, diversifying cropland by growing strips of different crops using conventional machinery, may be a viable strategy to promote natural predat...

Larger geographical areas contain more species—an observation raised to a law in ecology. Less explored is whether biodiversity changes are accompanied by a modification of interaction networks. We use data from 32 spatial interaction networks from different ecosystems to analyse how network structure changes with area. We find that basic community...

In their response to our paper on harnessing biodiversity in agricultural landscapes [1], Stein-Bachinger et al. [2] argue that our statements in favour of reducing field size and crop diversification ‘have to be combined with reduced management intensity’ to be effective. While we acknowledge the role of reducing agricultural intensity for biodive...

Significance Finding entry points where policy has strong leverage to transform land systems for people and nature is pivotal. We develop an innovative framework to identify and evaluate such leverage points along land-use trajectories that account for path dependency. Applied to the biodiversity hotspot Madagascar, the framework reveals three leve...

Understanding how land-use change affects biodiversity is a fundamental step to develop effective conservation strategies in human-modified tropical landscapes. Here, we analyzed how land-use change through tropical small-scale agriculture affects endemic, exotic, and non-endemic native ant communities, focusing on vanilla landscapes in northeaster...

In their response to our paper on harnessing biodiversity-friendly landscapes [1], Brühl et al. [2] argue that we underestimate the benefits of banning synthetic pesticides in organic farming. We thank the authors for highlighting the importance of reducing pesticide applications for biodiversity conservation, an assessment that we share [3–5]. How...

To understand how plant-pollinator interactions respond to habitat fragmentation, we need novel approaches that can capture properties that emerge at broad scales, where multiple communities engage in metanetworks. Here we studied plant-pollinator interactions over 2 years on 29 calcareous grassland fragments selected along independent gradients of...

Wildflower plantings are an important mitigation tool within agri-environmental schemes to counter insect decline in resource-scarce agricultural landscapes. Effectiveness of wildflower plantings for insect conservation is typically studied at the community or species level. It is the individual, however, that is subject to changing abiotic and bio...

Urban areas are increasing in number and extent worldwide. Few other anthropogenic land uses alter landscapes in a more persistent fashion; however, the effects of urbansiation on biodiversity remain poorly studied. Here, we studied bird communities along the rural–urban interface of the Indian megacity Bengaluru. Birds were assessed with point cou...

Bats have been shown to provide successful pest suppression in different land-use systems globally. Recent research demonstrates high economic values of pest suppression by bats also in macadamia orchards, which is enhanced by natural habitat patches at orchard edges. We investigated the impact of the conversion of natural to agricultural (macadami...

We challenge the widespread appraisal that organic farming is the fundamental alternative to conventional farming for harnessing biodiversity in agricultural landscapes. Certification of organic production is largely restricted to banning synthetic agrochemicals, resulting in limited benefits for biodiversity but high yield losses despite ongoing i...

Agroforestry can contribute to an increase in tree cover in historically forested tropical landscapes with associated gains in biodiversity and ecosystem functioning, but only if established on open land instead of underneath a forest canopy. However, declines in yields with increasing shade are common across agroforestry crops, driving shade-tree...

Global pollinator declines and land-use change can lead to pollination limitation with implications for agricultural productivity. Hand pollination is used in agricultural production as a technique to manually pollinate crops. But the prevalence of hand pollination, as well as benefits and costs, remain unknown. We systematically reviewed the liter...

Urbanization is a major driver of land use change and biodiversity decline. While most of the ongoing and future urbanization hot spots are located in the Global South, the impact of urban expansion on agricultural biodiversity and associated functions and services in these regions has widely been neglected. Additionally, most studies assess biodiv...