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Featured researches published by David Fischer.


Integrated Environmental Assessment and Management | 2016

Initial recommendations for higher‐tier risk assessment protocols for bumble bees, Bombus spp. (Hymenoptera: Apidae)

Ana R. Cabrera; Maria Teresa Almanza; G Christopher Cutler; David Fischer; Silvia Hinarejos; Gavin Lewis; Daniel Nigro; Allen Olmstead; Jay Overmyer; Daniel Potter; Nigel E. Raine; Cory Stanley-Stahr; Helen Thompson; Jozef van der Steen

Global declines of bumble bees and other pollinator populations are of concern because of their critical role for crop production and maintenance of wild plant biodiversity. Although the consensus among scientists is that the interaction of many factors, including habitat loss, forage scarcity, diseases, parasites, and pesticides, potentially plays a role in causing these declines, pesticides have received considerable attention and scrutiny. In response, regulatory agencies have introduced more stringent pollinator testing requirements for registration and reregistration of pesticides, to ensure that the risks to pollinators are minimized. In this context, guidelines for testing bumble bees (Bombus spp.) in regulatory studies are not yet available, and a pressing need exists to develop suitable protocols for routine higher-tier studies with these non-Apis sp., social bees. To meet this need, Bayer CropScience LP, Syngenta Crop Protection LLC US, and Valent USA. Corporation organized a workshop bringing together a group of global experts on bumble bee behavior, ecology, and ecotoxicology to discuss and develop draft protocols for both semi-field (Tier II) and field (Tier III) studies. The workshop was held May 8-9, 2014, at the Bayer Bee Care Center, North Carolina, USA. The participants represented academic, consulting, and industry scientists from Europe, Canada, the United States, and Brazil. The workshop identified a clear protection goal and generated proposals for basic experimental designs, relevant measurements, and endpoints for both semifield (tunnel) and field tests. These initial recommendations are intended to form the basis of discussions to help advance the development of appropriate protocol guidelines.


Ecotoxicology | 2017

Toxic and heavy metals as a cause of crayfish mass mortality from acidified headwater streams

Jitka Svobodová; Karel Douda; David Fischer; Natalia Lapšanská; Pavel Vlach

Mining activities are responsible for high concentrations of metals in river networks in many parts of the world. Mining activities and the resulting high loads of heavy metals interact with intensive acid rain, and often have great consequences for biodiversity. However, considering the frequently episodic nature of these heavy acid rains, there is little detailed evidence of direct impacts. In 2011 we observed a massive mortality of noble crayfish and stone crayfish in Padrťsko Special Area of Conservation (SAC) in the Brdy Mountain region of the Czech Republic. Based on concentrations of metals (Al, Fe, As, Cd, Pb, Cu, Zn and Hg) in various tissues (gills, hepatopancreas, muscle) of both dead and live crayfish in this locality compared to reference populations, these crayfish had experienced long-term exposure to increased levels of these metals. Here we give detailed documentation of crayfish mortality associated with high metal concentrations in the gills and other tissues of these endangered invertebrates.


Integrated Environmental Assessment and Management | 2007

Refined Avian Risk Assessment for Aldicarb

Dwayne Robert James Moore; Scott Teed; Sara Rodney; Ryan Thompson; David Fischer

Aldicarb was recently reviewed by the US Environmental Protection Agency (USEPA) for re-registration eligibility. In this paper, we describe a refined avian risk assessment for aldicarb that was conducted to build upon the screening-level methods used by USEPA. The goal of the refined ERA was to characterize and understand better the risks posed by aldicarb to birds in areas where the pesticide is applied. Aldicarb is a systemic insecticide sold in granular form under the trade name Temik. It is applied directly to soil and is used to control mites, nematodes, and aphids on a variety of crops (e.g., cotton, potatoes, peanuts). Consumption of grit is necessary for proper digestion in many bird species, particularly for granivores and insectivores. Thus, aldicarb granules may be mistaken for grit by birds. The Granular Pesticide Avian Risk Assessment Model (GranPARAM) is described in a companion paper and was used to estimate the probability and magnitude of effects to flocks of birds that frequent aldicarb-treated fields. One hundred thirty-five exposure scenarios were modeled that together include a range of bird species, crops, application methods and rates, and regions in the United States. The results indicated that, even for the most sensitive bird species, the risks associated with the agricultural use of granular aldicarb are negligible to low. There are several reasons for the limited risk: 1) the Temik formulation includes a gypsum core and a graphite coating and is black in color, all of which have been shown to be unattractive to birds, and 2) the pesticide is applied subsurface and rapidly dissolves following contact with water. The fact that no bird kill incidents involving appropriate label uses of aldicarb have been conclusively documented in the United States over its 38 years of use supports the results of this refined risk assessment.


Aquatic Conservation-marine and Freshwater Ecosystems | 2012

The relationship between water quality and indigenous and alien crayfish distribution in the Czech Republic: patterns and conservation implications

Jitka Svobodová; Karel Douda; Monika Štambergová; JiŘí Picek; Pavel Vlach; David Fischer


Knowledge and Management of Aquatic Ecosystems | 2009

Recent distribution, population densities and ecological requirements of the stone crayfish (Austropotamobius torrentium) in the Czech Republic

Pavel Vlach; L. Hulec; David Fischer


Knowledge and Management of Aquatic Ecosystems | 2009

Microhabitat preferences of the stone crayfish Austropotamobius torrentium (Schrank, 1803)

Pavel Vlach; David Fischer; L. Hulec


Ecotoxicology | 2005

Accounting for Differing Exposure Patterns between Laboratory Tests and the Field in the Assessment of Long-term Risks of Pesticides to Terrestrial Vertebrates

David Fischer


Knowledge and Management of Aquatic Ecosystems | 2012

Stone crayfish in the Czech Republic: how does its population density depend on basic chemical and physical properties of water?

Pavel Vlach; Jitka Svobodová; David Fischer


Limnologica | 2017

Mitochondrial DNA provides evidence of a double origin for the stone crayfish Austropotamobius torrentium in the Elbe basin

Adam Petrusek; Pavel Pešek; Dan Leština; Peer Martin; David Fischer; Pavel Kozák; Pavel Vlach


Vodohospodářské technicko-ekonomické informace | 2016

Periodické vysychání toků: další faktor negativně ovlivňující populace našich raků

Jitka Svobodová; David Fischer; Eva Svobodová; Pavel Vlach

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Pavel Vlach

University of West Bohemia

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Jozef van der Steen

Wageningen University and Research Centre

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Karel Douda

Czech University of Life Sciences Prague

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Peer Martin

Humboldt University of Berlin

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