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Caspar A. Hallmann

Bio: Caspar A. Hallmann is an academic researcher from Radboud University Nijmegen. The author has contributed to research in topics: Population & Biodiversity. The author has an hindex of 12, co-authored 21 publications receiving 2557 citations.

Papers
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Journal ArticleDOI
18 Oct 2017-PLOS ONE
TL;DR: This analysis estimates a seasonal decline of 76%, and mid-summer decline of 82% in flying insect biomass over the 27 years of study, and shows that this decline is apparent regardless of habitat type, while changes in weather, land use, and habitat characteristics cannot explain this overall decline.
Abstract: Global declines in insects have sparked wide interest among scientists, politicians, and the general public. Loss of insect diversity and abundance is expected to provoke cascading effects on food webs and to jeopardize ecosystem services. Our understanding of the extent and underlying causes of this decline is based on the abundance of single species or taxonomic groups only, rather than changes in insect biomass which is more relevant for ecological functioning. Here, we used a standardized protocol to measure total insect biomass using Malaise traps, deployed over 27 years in 63 nature protection areas in Germany (96 unique location-year combinations) to infer on the status and trend of local entomofauna. Our analysis estimates a seasonal decline of 76%, and mid-summer decline of 82% in flying insect biomass over the 27 years of study. We show that this decline is apparent regardless of habitat type, while changes in weather, land use, and habitat characteristics cannot explain this overall decline. This yet unrecognized loss of insect biomass must be taken into account in evaluating declines in abundance of species depending on insects as a food source, and ecosystem functioning in the European landscape.

2,065 citations

Journal ArticleDOI
17 Jul 2014-Nature
TL;DR: The hypothesis that the most widely used neonicotinoid insecticide, imidacloprid, has a negative impact on insectivorous bird populations is investigated and it is shown that, in the Netherlands, local population trends were significantly more negative in areas with higher surface-water concentrations of imidcloprid.
Abstract: Recent studies have shown that neonicotinoid insecticides have adverse effects on non-target invertebrate species. Invertebrates constitute a substantial part of the diet of many bird species during the breeding season and are indispensable for raising offspring. We investigated the hypothesis that the most widely used neonicotinoid insecticide, imidacloprid, has a negative impact on insectivorous bird populations. Here we show that, in the Netherlands, local population trends were significantly more negative in areas with higher surface-water concentrations of imidacloprid. At imidacloprid concentrations of more than 20 nanograms per litre, bird populations tended to decline by 3.5 per cent on average annually. Additional analyses revealed that this spatial pattern of decline appeared only after the introduction of imidacloprid to the Netherlands, in the mid-1990s. We further show that the recent negative relationship remains after correcting for spatial differences in land-use changes that are known to affect bird populations in farmland. Our results suggest that the impact of neonicotinoids on the natural environment is even more substantial than has recently been reported and is reminiscent of the effects of persistent insecticides in the past. Future legislation should take into account the potential cascading effects of neonicotinoids on ecosystems.

766 citations

Journal ArticleDOI
TL;DR: In this paper, a group of conservation biologists deeply concerned about the decline of insect populations, reviewed what we know about the drivers of insect extinctions, their consequences, and how extinctions can negatively impact humanity.

392 citations

Journal ArticleDOI
TL;DR: A global ‘roadmap’ for insect conservation and recovery is proposed that entails the immediate implementation of several ‘no-regret’ measures that will act to slow or stop insect declines.
Abstract: To the Editor — A growing number of studies are providing evidence that a suite of anthropogenic stressors — habitat loss and fragmentation, pollution, invasive species, climate change and overharvesting — are seriously reducing insect and other invertebrate abundance, diversity and biomass across the biosphere1–8. These declines affect all functional groups: herbivores, detritivores, parasitoids, predators and pollinators. Insects are vitally important in a wide range of ecosystem services9 of which some are vitally important for food production and security (for example, pollination and pest control)10. There is now a strong scientific consensus that the decline of insects, other arthropods and biodiversity as a whole, is a very real and serious threat that society must urgently address11–13. In response to the increasing public awareness of the problem, the German government is committing funds to combat and reverse declining insect numbers13. This funding should act as a clarion call to other nations across the world — especially wealthier ones — to follow suit and to respond proactively to the crisis by addressing the known and suspected threats and implementing solutions. We hereby propose a global ‘roadmap’ for insect conservation and recovery (Fig. 1). This entails the immediate implementation of several ‘no-regret’ measures (Fig. 1, step 1) that will act to slow or stop insect declines. Among the initiatives we encourage are the following immediate measures: Taking aggressive steps to reduce greenhouse gas emissions; reversing recent trends in agricultural intensification including reduced application of synthetic pesticides and fertilizers and pursuing their replacement with agro-ecological measures; promoting the diversification and maintenance of locally adapted landuse techniques; increasing landscape heterogeneity through the maintenance of natural areas within the landscape matrix and ensuring the retention and creation of microhabitats within habitats which may be increasingly important for insects during extreme climatic events such as droughts or heatwaves; reducing identified local threats such as light, water or noise pollution, invasive species and so on; prioritizing the import of goods that are not produced at the cost of healthy, species-rich ecosystems; designing and deploying policies (for example, subsidies and taxation) to induce the innovation and adoption of insectfriendly technologies; enforcing stricter measures to reduce the introduction of alien species, and prioritizing nature-based tactics for their (long-term) mitigation; compiling and implementing conservation strategies for species that are vulnerable, threatened or endangered; funding educational and outreach programs, including those tailored to the needs of the wider public, farmers, land managers, decision makers and conservation professionals; enhancing ‘citizen science’ or ‘community science’ as a way of obtaining more data on insect diversity and abundance as well as engaging the public, especially in areas where academic or professional infrastructure is lacking; devising and deploying measures across agricultural and food value chains that favour insect-friendly farming, including tracking, labelling, certification and insurance schemes or outcome-based incentives that facilitate behavioural changes, and investing in capacity building to create a new generation of insect conservationists and providing knowledge and skills to existing professionals (particularly in developing countries). To better understand changes in insect abundance and diversity, research should aim to prioritize the following areas: Quantifying temporal trends in insect abundance, diversity and biomass by extracting long-term datasets from existing insect collections to inform new censuses; exploring the relative contributions of different anthropogenic stressors causing insect declines within and across different taxa; initiating long-term studies comparing insect abundance and diversity in different habitats and ecosystems along a management-intensity gradient and at the intersection of agricultural and natural habitats; designing and validating insectfriendly techniques that are effective, locally relevant and economically sound in agriculture, managed habitats and urban environments; promoting and applying standardized monitoring protocols globally and establishing long-term monitoring plots or sites based on such protocols, as well as increasing support for existing monitoring efforts; establishing an international governing body under the auspices of existing bodies (for example, the United Nations Environment Programme (UNEP) or the International Union for Conservation of Nature (IUCN)) that is accountable for documenting and monitoring the effects of proposed solutions on insect biodiversity in the longer term; launching public–private partnerships and sustainable financing initiatives with the aim of restoring, protecting and creating new vital insect habitats as well as managing key threats; increasing exploration and research to improve biodiversity assessments, with a focus on regional capacity building in understudied and neglected areas, and performing large-scale assessments of the conservation status of insect groups to help define priority species, areas and issues. Most importantly, we should not wait to act until we have addressed every key knowledge gap. We currently have enough information on some key causes of insect decline to formulate no-regret solutions whilst more data are compiled for lesserknown taxa and regions and long-term data are aggregated and assessed. Implementation should be accompanied by research that examines impacts, the results of which can be used to modify and improve the implementation of effective measures. Furthermore, such a ‘learning-by-doing’ approach ensures that these conservation strategies are robust to newly emerging pressures and threats. We must act now. ❐

167 citations

Journal ArticleDOI
TL;DR: The results broadly echo recent reported trends in insect biomass in Germany and elsewhere, suggesting that heavy species did not contribute disproportionately to biomass decline.
Abstract: Recently, reports of insect declines prompted concerns with respect to the state of insects at a global level. Here, we present the results of longer‐term insect monitoring from two locations in the Netherlands: nature development area De Kaaistoep and nature reserves near Wijster. Based on data from insects attracted to light in De Kaaistoep, macro‐moths (macro‐Lepidoptera), beetles (Coleoptera), and caddisflies (Trichoptera) have declined in the mean number of individuals counted per evening over the period of 1997–2017, with annual rates of decline of 3.8, 5.0 and 9.2%, respectively. Other orders appeared stable [true bugs (Hemiptera: Heteroptera and Auchenorrhyncha) and mayflies (Ephemeroptera)] or had uncertainty in their trend estimate [lacewings (Neuroptera)]. Based on 48 pitfall traps near Wijster, ground beetles (Coleoptera: Carabidae) showed a mean annual decline of 4.3% in total numbers over the period of 1985–2016. Nonetheless, declines appeared stronger after 1995. For macro‐moths, the mean of the trends of individual species was comparable to the annual trend in total numbers. Trends of individual ground beetle species, however, suggest that abundant species performed worse than rare ones. When translated into biomass estimates, our calculations suggest a reduction in total biomass of approximately 61% for macro‐moths as a group and at least 42% for ground beetles, by extrapolation over a period of 27 years. Heavier ground beetles and macro‐moths did not decline more strongly than lighter species, suggesting that heavy species did not contribute disproportionately to biomass decline. Our results broadly echo recent reported trends in insect biomass in Germany and elsewhere.

102 citations


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01 Jan 2016
TL;DR: The modern applied statistics with s is universally compatible with any devices to read, and is available in the digital library an online access to it is set as public so you can download it instantly.
Abstract: Thank you very much for downloading modern applied statistics with s. As you may know, people have search hundreds times for their favorite readings like this modern applied statistics with s, but end up in harmful downloads. Rather than reading a good book with a cup of coffee in the afternoon, instead they cope with some harmful virus inside their laptop. modern applied statistics with s is available in our digital library an online access to it is set as public so you can download it instantly. Our digital library saves in multiple countries, allowing you to get the most less latency time to download any of our books like this one. Kindly say, the modern applied statistics with s is universally compatible with any devices to read.

5,249 citations

Journal ArticleDOI
TL;DR: Food in the Anthropocene : the EAT-Lancet Commission on healthy diets from sustainable food systems focuses on meat, fish, vegetables and fruit as sources of protein.

4,710 citations

Journal ArticleDOI
18 Oct 2017-PLOS ONE
TL;DR: This analysis estimates a seasonal decline of 76%, and mid-summer decline of 82% in flying insect biomass over the 27 years of study, and shows that this decline is apparent regardless of habitat type, while changes in weather, land use, and habitat characteristics cannot explain this overall decline.
Abstract: Global declines in insects have sparked wide interest among scientists, politicians, and the general public. Loss of insect diversity and abundance is expected to provoke cascading effects on food webs and to jeopardize ecosystem services. Our understanding of the extent and underlying causes of this decline is based on the abundance of single species or taxonomic groups only, rather than changes in insect biomass which is more relevant for ecological functioning. Here, we used a standardized protocol to measure total insect biomass using Malaise traps, deployed over 27 years in 63 nature protection areas in Germany (96 unique location-year combinations) to infer on the status and trend of local entomofauna. Our analysis estimates a seasonal decline of 76%, and mid-summer decline of 82% in flying insect biomass over the 27 years of study. We show that this decline is apparent regardless of habitat type, while changes in weather, land use, and habitat characteristics cannot explain this overall decline. This yet unrecognized loss of insect biomass must be taken into account in evaluating declines in abundance of species depending on insects as a food source, and ecosystem functioning in the European landscape.

2,065 citations

Journal ArticleDOI
TL;DR: In this paper, a comprehensive review of 73 historical reports of insect declines from across the globe, and systematically assess the underlying drivers of insect extinction, reveals dramatic rates of decline that may lead to the extinction of 40% of the world's insect species over the next few decades.

1,754 citations

Journal ArticleDOI
01 Mar 1994-Nature
TL;DR: It is clear that the above can lead to confusion when scientists of different countries are trying to communicate with each other, so an internationally recognized system of naming organisms is created.
Abstract: It is clear that the above can lead to confusion when scientists of different countries are trying to communicate with each other. Another example is the burrowing rodent called a gopher found throughout the western United States. In the southeastern United States the term gopher refers to a burrowing turtle very similar to the desert tortoise found in the American southwest. One final example; two North American mammals known as the elk and the caribou are known in Europe as the reindeer and the elk. We never sing “Rudolph the Red-nosed elk”! Confused? This was the reason for creating an internationally recognized system of naming organisms. To avoid confusion, living organisms are assigned a scientific name based on Latin or Latinized words. The English sparrow is Passer domesticus or Passer domesticus (italics or underlining these two names is the official written representation of a scientific name). Using a uniform naming system allows scientists from all over the world to recognize exactly which life form a scientist is referring to. The naming process is called the binomial system of nomenclature. Passer is comparable to a surname and is called the genus, while domesticus is the specific or species name (like your given name) of the English sparrow. Now scientists can give all sparrow-like birds the genus Passer but the species name will vary. All similar genera (plural for genus) can be grouped into another, “higher” category (see below). Study the following for a more through understanding of taxonomy. Taxonomy Analogy Kingdom: Animalia Country

1,305 citations