Nico Blüthgen

Technical University of Darmstadt | TU · Department of Biology (Dept. 10)

Deforestation of tropical forests have resulted in extensive areas of secondary forests with the potential to restore biodiversity to former old-­ growth forest levels. The recovery of vertebrate communities is an essential component of biodiversity and ecosystem restoration, as vertebrates provide key ecosystem functions. However, little is known...

The Insect Calculator is based on many data sets compiled from various studies. In all studies, the biocenometer was used as a method in which arthropods are sampled from one m² using a suction sampler – a modified leaf blower. The aim is to provide an online tool that predicts the number of insects in a meadow. This prediction depends on the gree...

The biodiversity of tropical rainforests is under extreme pressure due to the expansion of agricultural land. Beyond the immediate risk of species extinction, the intensification of land use can alter species' behaviour with consequences for the entire ecosystem. In this study we investigated the impact of land use on the acoustic behaviour of cica...

Arthropods face a global decline attributed to habitat loss, climate change, pesticide use, and an intensification of land‐use practices such as mowing. Studies on the effects of mowing on arthropod abundance showed conflicting results potentially due to multiple factors, including study design, grassland management, sampling method, and arthropod...

Numerous studies have reported that observed species shifts in mountain areas lag behind expectations under current warming trends, however, the mechanisms remain poorly understood. One important mechanism might be microclimatic heterogeneity causing migration of species to cooler conditions under closed forest canopies, but evidence is scarce. We...

Pollination is an ecosystem process that is crucial to maintain biodiversity and ecosystem function. Bats are important pollinators in the tropics and are an integral part of complex plant–pollinator interaction networks. However, network analysis–based approaches are still scarce at the plant species and bat community levels. We used metabarcoding...

Insect decline and loss of biodiversity not only affect large‐scale agricultural landscapes, but are increasingly recognized in urban environments. It is undisputed that a greater supply of flowers in urban green spaces can provide insects with more food and habitat. However, it is still controversial whether native wild plants or non‐native orname...

With higher frequency and intensity of droughts predicted for many tropical forests, understanding the responses of plants and animals to changed climatic conditions will be increasingly important. Ants are considered ecosystem engineers in tropical rainforests due to their abundance and the diversity of functional roles they perform. Function in a...

Background Only a few decades ago, colorful, small‐scale, heterogeneous, and species‐rich hay meadows or extensive pastures were common, but have often been replaced by species‐poor, uniform, large‐scale multicut meadows. Technological advancements and improved efficiency in grassland management have come at the cost of biodiversity. Methods In Ge...

Recent losses in the abundance and diversity of arthropods have been documented in many regions and ecosystems. In grasslands, such insect declines are largely attributed to land use, including modern machinery and mowing regimes. However, the effects of different mowing techniques on arthropods remain poorly understood. Using 11 years of data from...

Ecological networks of species interactions are popular and provide powerful analytical tools for understanding variation in community structure and ecosystem functioning. However, network analyses and commonly used metrics such as nestedness and connectance have also attracted criticism. One major concern is that observed patterns are misinterpret...

Conservation programs need improved tools to measure the recovery of animal diversity across restoration gradients. We used soundscapes and expert identifications of bird species to calculate niche position (i.e., mean of environmental conditions across all areas a species occupies) and niche breadth (i.e., the standard deviation of the species dis...

Army ants are widely recognized as keystone species in neotropical rainforests due to their role as important arthropod predators. Their large‐scale raids involve thousands of workers scouring the forest floor in pursuit of prey, primarily capturing other invertebrates. Up to 20 species of army ants coexist in a rainforest, and dietary niche differ...

From hunting and foraging to clearing land for agriculture, humans modify forest biodiversity, landscapes, and climate. Forests constantly undergo disturbance–recovery dynamics and understanding them is a major objective of ecologists and conservationists. Chronosequences are a useful tool for understanding global restoration efforts. They represen...

Background Dung beetles provide many important ecosystem services, including dung decomposition, pathogen control, soil aeration, and secondary seed dispersal. Yet, the biology of most dung beetles remains unknown. Natural diets are poorly studied, partly because previous research has focused on choice or attraction experiments using few, easily ac...

Urban areas have profound impacts on local species diversity and composition through a set of intertwined changes in the environment. As the world is rapidly urbanising while simultaneously facing a biodiversity crisis, a better understanding of how urbanisation influences biodiversity is necessary. To test if and how urbanisation influences moth d...

Stingless bees are important pollinators in tropical forests. Yet, we know little about their foraging behavior (e.g., their nutritional requirements or their floral sources visited for resource collection). Many stingless bees not only depend vitally on pollen and nectar for food but also on resin for nest building and/or defense. However, it is u...

Plant–pollinator interactions are ecologically and economically important, and, as a result, their prediction is a crucial theoretical and applied goal for ecologists. Although various analytical methods are available, we still have a limited ability to predict plant–pollinator interactions. The predictive ability of different plant–pollinator inte...

Tropical forest recovery is fundamental to addressing the intertwined climate and biodiversity loss crises. While regenerating trees sequester carbon relatively quickly, the pace of biodiversity recovery remains contentious. Here, we use bioacoustics and metabarcoding to measure forest recovery post-agriculture in a global biodiversity hotspot in E...

Agricultural grasslands have undergone rapid change in recent years: Only a few decades ago, colorful, small-scale, heterogeneous, species-rich hay meadows or extensive pastures were common, and have often been replaced by species-poor, uniform, large-scale, multi-cut meadows. Technological advances and agricultural efficiency have increased at the...

Forests canopy gaps play an important role in forest ecology by driving the forest mosaic cycle and creating conditions for rapid plant reproduction and growth. The availability of young plants, which represent resources for herbivores, and modified environmental conditions with greater availability of light and higher temperatures, promote the col...

Plant diversity can increase productivity. One mechanism behind this biodiversity effect is facilitation, which is when one species increases the performance of another species. Plants with extrafloral nectaries (EFNs) establish defense mutualisms with ants. However, whether EFN plants facilitate defense of neighboring non‐EFN plants is unknown. Sy...

Insects are declining, but the underlying drivers and differences in responses between species are still largely unclear. Despite the importance of forests, insect trends therein have received little attention. Using 10 years of standardized data (120,996 individuals; 1,805 species) from 140 sites in Germany, we show that declines occurred in most...

Understanding ecosystem recovery after perturbation is crucial for ecosystem conservation. Mutualisms contribute key functions for plants such as pollination and seed dispersal. We modelled the assembly of mutualistic networks based on trait matching between plants and their animal partners that have different degrees of specialization on plant tra...

Declines in species richness and abundance of insects over the last decades are often driven by anthropogenic land use and can have severe consequences for ecosystem functioning. Many studies investigated the effects of land-use intensification on the distribution of phenotypic traits across species at the community level, often with mixed results....

Microhabitat differentiation of species communities such as vertical stratification in tropical forests contributes to species coexistence and thus biodiversity. However, little is known about how the extent of stratification changes during forest recovery and influences community reassembly. Environmental filtering determines community reassembly...

Sparked by reports of insect declines of unexpected extent, there has been a surge in the compilation and analysis of insect time series data. While this effort has led to valuable databases, disagreement remains as to whether, where and why insects are declining. The 'why' question is particularly important because successful insect conservation w...

Understanding whether land use intensification causes regime shifts is of key importance for management, particularly if these shifts are associated with thresholds separating different ecosystem states and with hysteretic dynamics. Here we use a unique, long-term grassland database to identify thresholds in the response of 16 ecosystem functions a...

The impact of local biodiversity loss on ecosystem functioning is well established, but the role of larger-scale biodiversity dynamics in the delivery of ecosystem services remains poorly understood. Here we address this gap using a comprehensive dataset describing the supply of 16 cultural, regulating and provisioning ecosystem services in 150 Eur...

Keystone species are disproportionately important for ecosystem functioning. While all species engage in multiple interaction types with other species, keystone species importance is often defined based on a single dimension of their Eltonian niche, that is, one type of interaction (e.g. keystone predator). It remains unclear whether the importance...

With higher frequency and intensity of droughts predicted for many tropical forests, understanding the responses of plants and animals to changed conditions will be increasingly important. Ants are considered ecosystem engineers in tropical rainforests due to their abundance and the diversity of functional roles they perform. Diets of rainforest an...

Ecosystem functioning may directly or indirectly—via change in biodiversity—respond to land use. Dung removal is an important ecosystem function central for the decomposition of mammal faeces, including secondary seed dispersal and improved soil quality. Removal usually increases with dung beetle diversity and biomass. In forests, dung removal can...

Understanding ecosystem recovery after perturbation is crucial for ecosystem conservation. Mutualisms contribute key functions for plants such as pollination and seed dispersal. We modelled the assembly of mutualistic networks based on trait matching between plants and their animal partners that have different degrees of specialization on plant tra...

Space and time promote variation in network structure by affecting the likelihood of potential interactions. However, little is known about the relative roles of ecological and biogeographical processes in determining how species interactions vary across space and time. Here we study the spatiotemporal variation in predator–prey interaction network...

Regrowing secondary forests dominate tropical regions today, and a mechanistic understanding of their recovery dynamics provides important insights for conservation. In particular, land‐use legacy effects on the fauna have rarely been investigated. One of the most ecologically dominant and functionally important animal groups in tropical forests ar...

Temporal trends in insect numbers vary across studies and habitats, but drivers are poorly understood. Suitable long-term data are scant and biased, and interpretations of trends remain controversial. By contrast, there is substantial quantitative evidence for drivers of spatial variation. From observational and experimental studies, we have gained...

Species interaction networks are subject to natural and anthropogenic disturbances that lead to their disassembly, while natural regeneration or restoration efforts facilitate their reassembly. Previous models for assembling ecological networks did not include stochasticity at the level of population dynamics (e.g., demographic noise, environmental...

Context Current diversity and species composition of ecological communities can often not exclusively be explained by present land use and landscape structure. Historical land use may have considerably influenced ecosystems and their properties for decades and centuries. Objectives We analysed the effects of present and historical landscape struct...

Background How land use shapes biodiversity and functional trait composition of animal communities is an important question and frequently addressed. Land-use intensification is associated with changes in abiotic and biotic conditions including environmental homogenization and may act as an environmental filter to shape the composition of species c...

In tropical forests, primary dispersal by animals is the most important form of seed dispersal. Dung beetles are secondary seed dispersers attracted to mammal feces. When they bury dung of frugivorous mammals, they move seeds to new sites, possibly protecting them from seed predation or pathogens, or moving to better micro‐climates and away from co...

Background Ant colonies are plagued by a diversity of arthropod guests, which adopt various strategies to avoid or to withstand host attacks. Chemical mimicry of host recognition cues is, for example, a common integration strategy of ant guests. The morphological gestalt and body size of ant guests have long been argued to also affect host hostilit...

Comprehension of the benefits involved in mutualisms is crucial to disentangle the role of interactions in the structure and functioning of populations, communities and ecosystems. In ant-plant mutualisms, benefits provided by plants to ants are immediately recognizable, but reverse benefits are less obvious, conditional and accumulate over longer...

Tropical rainforests are among the most diverse biomes on Earth. While species inventories are far from complete for any tropical rainforest, even less is known about the intricate species interactions that form the basis of these ecological communities. One fascinating but poorly studied example are the symbiotic associations between army ants and...

Climate change is enhancing the annual mean temperature and the risk for droughts and natural disasters. Hot and dry summers not only have a negative impact on forest performance, but also affect fundamental ecosystem processes such as litter decomposition and nutrient cycling and the organisms involved. Oribatid mites are sexually or parthenogenet...

A new study shows that large mammals in an African savanna not only modify the vegetation but also strongly alter interaction networks between plants and pollinators. These insights raise fundamental yet unresolved questions about spatial dimensions of experiments, species interaction networks and ecosystems.

Land-use intensification is a major driver of biodiversity loss. However, understanding how different components of land use drive biodiversity loss requires the investigation of multiple trophic levels across spatial scales. Using data from 150 agricultural grasslands in central Europe, we assess the influence of multiple components of local-and l...

In the course of global climate change, central Europe is experiencing more frequent and prolonged periods of drought. The drought years 2018 and 2019 affected European beeches ( Fagus sylvatica L.) differently: even in the same stand, drought damaged trees neighboured healthy trees, suggesting that the genotype rather than the environment was resp...

Biological control of pest insects by natural enemies may be an effective, cheap and environmentally friendly alternative to synthetic pesticides. The cosmopolitan parasitoid wasp species Bracon brevicornis Wesmael and B. hebetor Say (Hymenoptera: Braconidae) use lepidopteran species as hosts, including insect pests like Ephestia kuehniella or Ostr...

Increased climate variability as a result of anthropogenic climate change can threaten the functioning of ecosystem services. However, diverse responses to climate change among species (response diversity) can provide ecosystems with resilience to this growing threat. Measuring and managing response diversity and resilience to global change are key...

The importance of keystone species is often defined based on a single type of interaction (e.g., keystone predator). However, it remains unclear whether this functional importance extends across interaction types. We conducted a global meta-analysis of interaction networks to examine whether species functional importance in one niche dimension is m...

Decomposition, vegetation regeneration, and biological control are essential ecosystem functions, and animals are involved in the underlying processes, such as dung removal, seed removal, herbivory, and predation. Despite evidence for declines of animal diversity and abundance due to climate change and land-use intensification, we poorly understand...

We explore the hypothesis that intraspecific trait variability can be per se beneficial for the plant when the curvature of the herbivore response to this trait is concave downwards. This hypothesis is based on a mathematical relation for nonlinear averaging (Jensen's inequality), leading to reduced herbivory when the trait distribution becomes bro...

Intensive land use has been shown to alter the composition and functioning of soil communities. Due to their low dispersal ability, oribatid mites are particularly vulnerable to land-use intensification and species which are not adjusted to management-related disturbances become less abundant. We investigated how different land-use parameters in fo...

Background Forests perform various important ecosystem functions that contribute to ecosystem services. In many parts of the world, forest management has shifted from a focus on timber production to multi-purpose forestry, combining timber production with the supply of other forest ecosystem services. However, it is unclear which forest types provi...

• Reports of major losses in insect biodiversity have stimulated an increasing interest in temporal population changes. Existing datasets are often limited to a small number of study sites, few points in time, a narrow range of land‐use intensities and only some taxonomic groups, or they lack standardised sampling. While new monitoring programs hav...

In the course of global climate change, central Europe is experiencing more frequent and prolonged periods of drought. The drought years 2018 and 2019 affected European beeches ( Fagus sylvatica L.) differently: even in the same stand, drought damaged trees neighboured healthy trees, suggesting that the genotype rather than the environment was resp...

Most studies of plant–animal mutualistic networks have come from a temporally static perspective. This approach has revealed general patterns in network structure, but limits our ability to understand the ecological and evolutionary processes that shape these networks and to predict the consequences of natural and human‐driven disturbance on specie...

Reports of major losses in biodiversity have stimulated an increasing interest in temporal population changes, particularly in insects, which had received little attention in the past. Existing long-term datasets are often limited to a small number of study sites, few points in time, a narrow range of land-use intensities and only some taxonomic gr...

Context Landscape and local habitat traits moderate wild bee communities. However, whether landscape effects differ between local habitat types is largely unknown. Objectives We explored the way that wild bee communities in three distinct habitats are shaped by landscape composition and the availability of flowering plants by evaluating divergence...

Most organisms are defended against others, and defenses such as secondary metabolites in plants vary across species, individuals, and subindividual organs. Plant leaves show an impressive variability in quantitative defense levels, even within the same individual. Such variation might mirror physiological constraints or represent an evolved trait....

Table of contents S1: Relation of seed removal rate with short-term precipitation S2: Details of herbivory measurements S3: Details of processing explanatory data S4: GLMM results in detail S5: Comparison of the mean effect sizes of short-term vs. medium-term land-use variables in grasslands S6: Process rates in detail S7: Effects of the vegetation...

One of the largest species in its genus, Odontomachus davidsoni Hoenle, Lattke & Donoso, sp. nov. is described from workers and queens collected at lowland forests in the Chocó-Darién bioregion in coastal Ecuador. The workers are characterized by their uniform red coloration, their large size (16–18 mm body length), and their frontal head striation...

Massive declines in insect biodiversity and biomass are reported from many regions and habitats. In urban areas, creation of native wildflower meadows is one option to support insects and reduce maintenance costs of urban green spaces. However, benefits for insect conservation may depend on previous land use, and the size and location of new wildfl...