Teja Tscharntke

Teja Tscharntke
Georg-August-Universität Göttingen | GAUG

Professor

About

717
Publications
449,287
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Introduction
Teja Tscharntke is a Professor of Agroecology at the University of Göttingen, studied sociology and biology in Marburg and Gießen, did his doctorate in Hamburg and habilitated in Karlsruhe. His research focuses on landscape perspectives on biodiversity patterns and associated ecosystem services of temperate and tropical regions with a strong interest in multidisciplinary studies integrating socio-economic and ecological analyses.

Publications

Publications (717)
Article
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...
Article
Full-text available
Animals provide services such as pollination and pest control in cacao agro-forestry systems, but also disservices. Yet, their combined contributions to crop yield and fruit loss are mostly unclear. In a full-factorial field experiment in northwestern Peru, we excluded flying insects, ants, birds and bats from cacao trees and assessed several produ...
Article
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...
Article
Although most of the wild bee species are ground-nesting, little is known about their nesting requirements and the conservation measures to promote ground-nesting bees. Calcareous grasslands are one of the most species-rich habitats in Central Europe and therefore essential for protecting bee diversity. The management practices of calcareous grassl...
Article
Apple is one of the most widely cultivated fruit crops worldwide, and apple yield benefits from pollination by insects. The global decline in wild pollinator populations raises concern about the adequacy of pollination services in apple production. Here, we present a global meta‐analysis of pollination in apple. We assembled from the literature a d...
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Full-text available
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...
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Organic farming supports higher biodiversity than conventional farming, but at the cost of lower yields. We conducted a meta‐analysis quantifying the trade‐off between biodiversity and yield, comparing conventional and organic farming. We developed a compatibility index to assess whether biodiversity gains from organic farming exceed yield losses,...
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Pollination services of cacao are crucial for global chocolate production, yet remain critically understudied, particularly in regions of origin of the species. Notably, uncertainties remain concerning the identity of cacao pollinators, the influence of landscape (forest distance) and management (shade cover) on flower visitation and the role of po...
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Urbanization is 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 assessed how urbanization affects the functional response of f...
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The effectiveness of agri-environment schemes depends on scheme type, taxon and landscape. Here, we show how spatial scale, i.e. studied transect, field or farm level, and controlling for yield loss, can drastically change the evaluation of biodiversity benefits of on-field (organic farming) vs. off-field (flower strips) schemes. We selected ten ag...
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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...
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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...
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Aim To understand effects of fire history and landscape composition on butterfly diversity in a fragmented agricultural landscape. Location We studied critically endangered renosterveld remnants within the fynbos biome in the Swartland municipality, Western Cape, South Africa, a global biodiversity hotspot. Method We selected survey sites on reno...
Article
Intensification of agricultural production and simplification of landscape structure have negatively affected arthropod communities, in particular since the end of Second World War. Agri-environment schemes may partly compensate for these losses and enhance arthropod populations, but their effectiveness is higher in simple landscapes rather than co...
Article
Seventy five percent of the world's food crops benefit from insect pollination. Hence, there has been increased interest in how global change drivers impact this critical ecosystem service. Because standardized data on crop pollination are rarely available, we are limited in our capacity to understand the variation in pollination benefits to crop y...
Article
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...
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1. 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, i.e., diversifying cropland by growing strips of different crops using conventional machinery, may be a viable strategy to promote natural predat...
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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...
Article
Agricultural expansion and intensification increasingly threaten birds and bats, especially insectivorous species from the tropics. Cacao agroforests in tropical rainforest areas have been shown to support higher bird and bat biodiversity than other land-use systems, but their suitability for tropical dry forest biodiversity remains unclear. We pre...
Article
Animal pollinators are globally threatened by anthropogenic land use change and agricultural intensification. The yield of many food crops is therefore negatively impacted because they benefit from biotic pollination. This is especially the case in the tropics. For instance, fruit set of Coffea arabica has been shown to increase by 10–30% in planta...
Chapter
Despite a developing understanding of how landscape level processes moderate biodiversity patterns and ecosystem functioning, key questions remain unresolved, therefore limiting our ability to manage for biodiversity conservation and ecosystem functioning at the most appropriate scales. These questions have remained unanswered because studies in ag...
Preprint
Full-text available
Production of cocoa, the third largest trade commodity globally has experienced climate related yield stagnation since 2016, forcing farmers to expand production in forested habitats and to shift from nature friendly agroforestry systems to intensive monocultures. The goal for future large-scale cocoa production combines high yields with biodiversi...
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Stabilizing agricultural production is fundamental to food security. At the national level, increasing the effective diversity of cultivated crops has been found to increase temporal production stability, i.e., the year-to-year stability of total caloric production of all crops combined. Here, we specifically investigated these effects at the regio...
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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...
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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...
Article
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...
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Background and aims – Agricultural intensification and loss of farmland heterogeneity have contributed to population declines of wild bees and other pollinators, which may have caused subsequent declines in insect-pollinated wild plants. Material and methods – Using data from 37 studies on 22 pollinator-dependent wild plant species across Europe, w...
Chapter
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...
Article
Global environmental change is critically endangering plant-pollinator interactions, as shown in this issue of One Earth by Huang et al., who combine phenomenological models with empirical plant-pollinator networks. Losses of pollination services in agricultural landscapes also endanger global food security but meeting the challenge of better under...
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The legacy of the ‘SL > SS principle’, that a single or a few large habitat patches (SL) conserve more species than several small patches (SS), is evident in decisions to protect large patches while down-weighting small ones. However, empirical support for this principle is lacking, and most studies find either no difference or the opposite pattern...
Article
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...
Article
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...
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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...
Article
The importance of wild bees for crop pollination is well established, but less is known about which species contribute to service delivery to inform agricultural management, monitoring and conservation. Using sites in Great Britain as a case study, we use a novel qualitative approach combining ecological information and field survey data to establi...
Article
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...
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Across Europe, calcareous grasslands become increasingly fragmented and their quality deteriorates through abandonment and land use intensification, both affecting biodiversity. Here, we investigated local and landscape effects on diversity patterns of several taxonomic groups in a landscape of highly fragmented calcareous grassland remnants. We su...
Article
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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...
Chapter
Reports on recent declines in insect biodiversity have prompted discussions on how to assess insect species numbers across a wide range of different habitats and on large spatial scales. Previous approaches were often restricted to particular habitat types (such as calcareous grasslands) or taxa (such as butterflies). Here, we show that setting up...
Chapter
Fueled by debates on the causes and consequences of biodiversity decline worldwide, many countries are now employing biodiversity monitoring programs of various scope, intensity and scale. While these programs will be important to set a baseline for managing a country´s biological diversity, the availability of detailed data may take too long for t...
Article
Agricultural intensification has led to dramatic losses of species and associated ecosystem services. In the European Union, agri‐environment schemes (AES) have been developed to mitigate these challenges. There are two opposing AES strategies, targeting either production or non‐production areas. Organic farming focuses on production and conservati...
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Article
Full-text available
Banks-Leite et al. (2021) claim that our suggestion of preserving ≥40% forest cover lacks evidence and can be problematic. We find these claims unfounded, and discuss why conservation planning urgently requires valuable, well-supported, and feasible general guidelines like the 40% criterion. Using region-specific thresholds worldwide is unfeasible...
Article
Full-text available
Aim: Northeastern Madagascar is a hotspot of plant diversity, but vanilla and rice farming are driving land-use change, including slash-and-burn management. It still remains unknown how land-use change and land-use history affect richness and composition of endemic, native and exotic herbaceous plant species. Location: Northeastern Madagascar. Me...
Article
Cocoa (Theobroma cacao L.), a major commodity globally, depends on insects for pollination. However, the cocoa pollinator identity is largely unknown and there are important knowledge gaps regarding landscape and farm-level management driving pollinators. Here we analyzed flower visitation with two approaches to quantify how landscape and farm-leve...
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Full-text available
Pollinator declines in agricultural landscapes are driven by multiple stressors, but potential interactions of these remain poorly studied. Using a highly replicated semi-field study with 56 meso-cosms of varying wild plant diversity (2-16 species) and oilseed rape treated with a neonicotinoid, we tested the interacting effects of resource diversit...
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Full-text available
While an increasing number of studies indicate that the range, diversity and abundance of many wild pollinators has declined, the global area of pollinator-dependent crops has significantly increased over the last few decades. Crop pollination studies to date have mainly focused on either identifying different guilds pollinating various crops, or o...
Article
While an increasing number of studies indicate that the range, diversity and abundance of many wild pollinators has declined, the global area of pollinator-dependent crops has significantly increased over the last few decades. Crop pollination studies to date have mainly focused on either identifying different guilds pollinating various crops, or o...
Preprint
Measuring the effectiveness of agri-environment schemes depends on scheme type, taxon and landscape. Here we show how spatial scale, i.e. studied transect, field or farm level, and controlling for yield loss, can drastically change the evaluation of biodiversity benefits of on-field (organic farming) vs. off-field (flower strips) schemes. Transects...
Article
Full-text available
Measuring habitat specialisation is pivotal for predicting species extinctions and for understanding consequences on ecosystem functioning. Here, we sampled pollinator and natural enemy communities in all major habitat types occurring across multiple agricultural landscapes and used species-habitat networks to determine how habitat specialisation c...
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Full-text available
Context Biological weed control by seed predators is an ecosystem service reducing weed population densities in agricultural landscapes. Drivers of seed predation are manifold and may change with spatial scales considered. Objectives We aimed at identifying the functional identity of seed predators, food web interactions and feeding links between w...
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Full-text available
Strong declines of grassland species diversity in small and isolated grassland patches have been observed at local and landscape scales. Here, we study how plant–herbivore interaction webs and habitat specialisation of leafhopper communities change with the size of calcareous grassland fragments and landscape connectivity. We surveyed leafhoppers a...
Article
Agri-environment schemes, like flower fields, have been implemented in the EU to counteract the dramatic decline of farmland biodiversity. Farmers in Lower Saxony, Germany, may receive payments for three flower field types: annual, perennial (five years old), and mixed flower fields composed of yearly alternating annual and biannual parts. We asses...
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Global agrobiodiversity is threatened by the replacement of traditional, locally adapted crop varieties with high-yielding and hybrid varieties during the past 60 years, resulting in associated losses of crop, variety, and allele diversity. Locally adapted, traditional varieties are known to perform equal or even better under environmental stress c...
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In Central Europe, agricultural intensification has led to increasing fragmentation and loss of semi-natural habitats. In turn, ecosystem services such as pollination are being lost when insect pollinators depend on semi-natural habitats. Calcareous grasslands are a highly threatened, biodiverse type of semi-natural habitat that may substantially s...
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Full-text available
Aim It is widely accepted that biodiversity is influenced by both niche‐related and spatial processes from local to global scales. Their relative importance, however, is still disputed, and empirical tests are surprisingly scarce at the global scale. Here, we compare the importance of area (as a proxy for pure spatial processes) and environmental h...
Article
Bees provide important pollination services for crops, but pollination limitation is a common problem in agricultural landscapes worldwide. To promote ecological intensification in fruit production, more knowledge is needed concerning the interacting effects of insect pollination services and soil fertility on crop quality and quantity. We investig...
Preprint
Banks-Leite et al. (2021) claim that our suggestion of preserving ≥40% forest cover lacks evidence and can be problematic. We find these claims unfounded, and discuss why conservation planning urgently requires valuable, well-supported, and feasible general guidelines like the 40% criterion. Using region-specific thresholds worldwide is unfeasible...
Preprint
In biodiversity conservation, the “SL > SS principle” that a single (or few) large habitat patches (SL) conserve more species than several small patches (SS) is used to prioritize protection of large patches while down-weighting small ones. However, empirical support for this principle is lacking; most studies find SS > SL. We propose a research ag...
Article
Full-text available
The global decline in invertebrate diversity requires urgent conservation interventions. However, identifying priority conservation areas for invertebrates remains a significant challenge. We hypothesized that aligning the conservation of invertebrate biodiversity with climate change mitigation offers a solution. As both soil carbon storage and inv...
Article
Full-text available
Earth is home to over 350,000 vascular plant species that differ in their traits in innumerable ways. A key challenge is to pre- dict how natural or anthropogenically driven changes in the identity, abundance and diversity of co-occurring plant species drive important ecosystem-level properties such as biomass production or carbon storage. Here, we...
Article
Reconciling biodiversity conservation with increasing demand for agricultural production is a major challenge. A long-running discourse that addresses this challenge is the land-sparing vs land-sharing debate. However, the land-sparing vs land-sharing framework has also been criticized for favouring a dichotomous worldview, which contradicts the re...
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Full-text available
A large body of research shows that biodiversity loss can reduce ecosystem functioning. However, much of the evidence for this relationship is drawn from biodiversity–ecosystem functioning experiments in which biodiversity loss is simulated by randomly assembling communities of varying species diversity, and ecosystem functions are measured. This r...
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Many farmers are facing high economic risks if pollinator declines continue or temporal and spatial variation in wild bee communities cause reduced pollination services. Co‐flowering crops might compete for pollinators, while they also might facilitate the delivery of pollination services. This rarely studied topic is of particular interest with re...