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Dr Dirk Sanders

Dr Dirk Sanders

Research Fellow

 01326 259467

 Environment and Sustainability Institute desk 40, 1.03

 

Environment and Sustainability Institute, University of Exeter, Penryn Campus, Penryn, Cornwall, TR10 9FE, UK

I am interested in how the structure of ecological communities is related to certain ecosystem processes, such as predation, pollination and ecosystem engineering, and the stability of these communities. In this context I aim to understand the interplay of mutualistic and antagonistic, trophic and non-trophic interactions.

Qualifications

2008 PhD (University of Goettingen)
2004 Diploma in Biology (University of Goettingen, Germany)

Career

2015– Research Fellow, University of Exeter, Cornwall Campus

2013–2015 Associate Research Fellow, University of Exeter, Cornwall Campus
2011–2013 Assistant with independent research, University of Bern, Switzerland
2010–2011 Post-doctoral research fellow, University of Exeter, Cornwall Campus
2009–2010 Post-doctoral research fellow, Imperial College London, Silwood Park

Jumping spider Aelurillus v-insignitus

Jumping spider Aelurillus v-insignitus. Photo credit: Dirk Sanders

The parasitoid Aphidius megourae attacking the aphid Megoura viciae

The parasitoid Aphidius megourae attacking the aphid Megoura viciae. Photo credit: Dirk Sanders

Myrmica rubra

Myrmica rubra. Photo credit: Dirk Sanders

Research

Research interests

My research explores the role of carnivore species in shaping ecological communities and their importance for community stability and ecosystem functions. As carnivores appear especially vulnerable to global change and with their loss often causing disproportionate changes in community composition across trophic levels, there is a need to understand the implications of carnivore extinctions for ecosystem stability. My research aims to understand the ecological consequences of such losses and how they are transmitted through the network of interacting species. Experiments are a powerful tool to test this impact as they demonstrate the actual community response to species loss. I have manipulated predator presence and abundance, predator functional diversity, and the presence of predators that also act as mutualists or ecosystem engineers in various field experiments. As model systems I use (i) aphids, their parasitoids and hyperparasitoids, (ii) ants and spiders as ubiquitous generalist predators and (iii) soil bacteria and plasmids.

Research projects

1. Vulnerability of ecological communities to extinction cascades (NERC)
Initial species losses are often followed by secondary extinctions of other species, for not always obvious reasons, with the danger that this leads to a cascade of further extinctions and ecosystem collapse. Predicting these cascades is challenging and requires a detailed understanding of how the interconnectedness of species in ecosystems affects the transmission of human impacts on one species to other species that are not directly linked to it. This is particularly important for species at higher trophic levels (carnivores) which are most vulnerable to extinction. The idea has long existed that species of carnivore that specialise on different prey have positive effects on each other by limiting their prey populations and thereby preventing one prey species from outcompeting the other. A consequence of this is that if a carnivore is lost from the community, its prey is released from control and may subsequently out-compete the other prey species leaving the other carnivore without food and facing extinction. This is potentially an important mechanism by which extinction cascades occur, however, it is difficult to obtain experimental evidence for such effects. We study these mechanisms in field experiments using aphid-parasitoid communities.

2. Integration of food webs and ecosystem engineering
Ecosystem engineering (the modification of the physical environment by organisms) is an important interaction in most ecosystems. When these engineers are trophically coupled to food webs as producers, consumers or decomposers, there is obviously the potential for trophic feedbacks to alter engineer density and engineering activity. This can then lead to a change in the degree to which the environment is modified, subsequent modification of trophic interactions affecting food webs dynamics and stability.

3. Functional role of generalist predators
Ants and spiders are ubiquitous generalist predators in many terrestrial ecosystems; they have a very complex role as they can act as predators, competitors, intraguild predators, mutualists and engineers. Understanding the interplay between these different kinds of interactions will help to better understand their function within ecological communities.

Selected Publications

Sanders, D., Kehoe, R., van Veen, F.J.F., McLean, A., Godfray, H.C.J, Dicke, M., Gols, R., Frago, E. (2016) Protective insect symbiont leads to cascading extinctions and community collapse. Ecology Letters 19. http://onlinelibrary.wiley.com/doi/10.1111/ele.12616/full

Sanders D., Moser, M., Newton, J., van Veen, F.J.F. (2016) Trophic assimilation efficiency markedly increases at higher trophic levels in 4-level host-parasitoid food chain. Proceedings of the Royal Society Bhttp://rspb.royalsocietypublishing.org/content/283/1826/20153043.abstract

Sanders D., Kehoe, R., van Veen F.J.F. (2015) Experimental evidence for the population-dynamic mechanisms underlying extinction cascades of carnivores. Current Biology 25, Issue 23, 3106–3109. http://www.sciencedirect.com/science/article/pii/S0960982215012452

Sanders D., Sutter, L., van Veen F.J.F. (2013) The loss of indirect interactions leads to cascading extinctions of carnivores. Ecology Letters, doi: 10.1111/ele.12096 http://onlinelibrary.wiley.com/doi/10.1111/ele.12096/full 

Sanders, D. & van Veen, F.J.F. (2011) Ecosystem engineering and predation: The multi-trophic impact of two ant species. Journal of Animal Ecology 80, 569–576. http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2656.2010.01796.x/full

 

Key publications | Publications by category | Publications by year

Publications by category


Journal articles

Sanders D, Kehoe R, Cruse D, Van Veen F, Gaston KJ (In Press). Low levels of artificial light at night strengthen top-down control in insect food web. Current Biology Full text.
Sanders D, Gaston KJ (2018). How ecological communities respond to artificial light at night. J Exp Zool a Ecol Integr Physiol Abstract.  Author URL.  Full text.
Perkins MJ, Inger R, Bearhop S, Sanders D (2018). Multichannel feeding by spider functional groups is driven by feeding strategies and resource availability. Oikos, 127(1), 23-33. Abstract.
Sanders D, Kehoe R, Thebault E, Van Veen FJF (2018). Trophic redundancy reduces vulnerability to extinction cascades. Proceedings of the National Academy of Sciences Full text.
Zhong Z, Li X, Pearson D, Wang D, Sanders D, Zhu Y, Wang L (2017). Ecosystem engineering strengthens bottom-up and weakens top-down effects via trait-mediated indirect interactions. Proc Biol Sci, 284(1863). Abstract.  Author URL.
Sanders D, Kehoe R, van Veen FF, McLean A, Godfray HCJ, Dicke M, Gols R, Frago E (2016). Defensive insect symbiont leads to cascading extinctions and community collapse. Ecol Lett, 19(7), 789-799. Abstract.  Author URL.  Full text.
Turrini T, Sanders D, Knop E (2016). Effects of urbanization on direct and indirect interactions in a tri-trophic system. Ecological Applications, 26(3), 664-675. Abstract.
Kehoe R, Frago E, Barten C, Jecker F, van Veen F, Sanders D (2016). Nonhost diversity and density reduce the strength of parasitoid–host interactions. Ecology and Evolution, 6(12), 4041-4049. Abstract.  Full text.
Sanders D, Moser A, Newton J, van Veen FJF (2016). Trophic assimilation efficiency markedly increases at higher trophic levels in four-level host-parasitoid food chain. Proc Biol Sci, 283(1826). Abstract.  Author URL.  Full text.
Sanders D, Kehoe R, Tiley K, Bennie J, Cruse D, Davies TW, Frank van Veen FJ, Gaston KJ (2015). Artificial nighttime light changes aphid-parasitoid population dynamics. Sci Rep, 5 Abstract.  Author URL.  Full text.
Sanders D, Kehoe R, van Veen FJF (2015). Experimental Evidence for the Population-Dynamic Mechanisms Underlying Extinction Cascades of Carnivores. Curr Biol, 25(23), 3106-3109. Abstract.  Author URL.
Sanders D, Vogel E, Knop E (2015). Individual and species-specific traits explain niche size and functional role in spiders as generalist predators. Journal of Animal Ecology, 84(1), 134-142. Abstract.
Sanders D, Vogel E, Knop E (2015). Individual and species-specific traits explain niche size and functional role in spiders as generalist predators. J Anim Ecol, 84(1), 134-142. Abstract.  Author URL.
Sanders D, Jones CG, Thébault E, Bouma TJ, van der Heide T, van Belzen J, Barot S (2014). Integrating ecosystem engineering and food webs. Oikos
Sanders D, Jones CG, Thébault E, Bouma TJ, van der Heide T, van Belzen J, Barot S (2014). Integrating ecosystem engineering and food webs. Oikos, 123(5), 513-524. Abstract.
Knop E, Zünd J, Sanders D (2014). Interactive prey and predator diversity effects drive consumption rates. Oikos, 123(10), 1244-1249. Abstract.
Knop E, Zünd J, Sanders D (2014). Interactive prey and predator diversity effects drive consumption rates. Oikos Abstract.
van Veen FJF, Sanders D (2013). Herbivore identity mediates the strength of trophic cascades on individual plants. ECOSPHERE, 4(5). Author URL.
Eggs B, Sanders D (2013). Herbivory in Spiders: the Importance of Pollen for Orb-Weavers. PLOS ONE, 8(11). Author URL.
Eggs B, Sanders D (2013). Herbivory in spiders: the importance of pollen for orb-weavers. PLoS ONE, 8(11). Abstract.
Sanders D, Sutter L, van Veen FJF (2013). The loss of indirect interactions leads to cascading extinctions of carnivores. Ecology Letters, 16(5), 664-669. Abstract.
Sanders D, Sutter L, van Veen FJF (2013). The loss of indirect interactions leads to cascading extinctions of carnivores. Ecol Lett, 16(5), 664-669. Abstract.  Author URL.
Sanders D, Van Veen FJF (2012). Indirect commensalism promotes persistence of secondary consumer species. Biology Letters, 8(6), 960-963. Abstract.
Sanders D, van Veen FJF (2011). Ecosystem engineering and predation: the multi-trophic impact of two ant species. Journal of Animal Ecology, 80(3), 569-576.
Sanders D, Schaefer M, Platner C, Griffiths GJK (2011). Intraguild interactions among generalist predator functional groups drive impact on herbivore and decomposer prey. Oikos, 120(3), 418-426. Abstract.
Sanders D, Entling MH (2011). Large variation of suction sampling efficiency depending on arthropod groups, species traits, and habitat properties. Entomologia Experimentalis et Applicata, 138(3), 234-243. Abstract.
Sanders D, van Veen FJF (2010). The impact of an ant–aphid mutualism on the functional composition of the secondary parasitoid community. Ecological Entomology, 35(6), 704-710. Abstract.

Publications by year


In Press

Sanders D, Kehoe R, Cruse D, Van Veen F, Gaston KJ (In Press). Low levels of artificial light at night strengthen top-down control in insect food web. Current Biology Full text.

2018

Sanders D, Gaston KJ (2018). How ecological communities respond to artificial light at night. J Exp Zool a Ecol Integr Physiol Abstract.  Author URL.  Full text.
Perkins MJ, Inger R, Bearhop S, Sanders D (2018). Multichannel feeding by spider functional groups is driven by feeding strategies and resource availability. Oikos, 127(1), 23-33. Abstract.
Sanders D, Kehoe R, Thebault E, Van Veen FJF (2018). Trophic redundancy reduces vulnerability to extinction cascades. Proceedings of the National Academy of Sciences Full text.

2017

Zhong Z, Li X, Pearson D, Wang D, Sanders D, Zhu Y, Wang L (2017). Ecosystem engineering strengthens bottom-up and weakens top-down effects via trait-mediated indirect interactions. Proc Biol Sci, 284(1863). Abstract.  Author URL.

2016

Sanders D, Kehoe R, van Veen FF, McLean A, Godfray HCJ, Dicke M, Gols R, Frago E (2016). Defensive insect symbiont leads to cascading extinctions and community collapse. Ecol Lett, 19(7), 789-799. Abstract.  Author URL.  Full text.
Turrini T, Sanders D, Knop E (2016). Effects of urbanization on direct and indirect interactions in a tri-trophic system. Ecological Applications, 26(3), 664-675. Abstract.
Kehoe R, Frago E, Barten C, Jecker F, van Veen F, Sanders D (2016). Nonhost diversity and density reduce the strength of parasitoid–host interactions. Ecology and Evolution, 6(12), 4041-4049. Abstract.  Full text.
Sanders D, Moser A, Newton J, van Veen FJF (2016). Trophic assimilation efficiency markedly increases at higher trophic levels in four-level host-parasitoid food chain. Proc Biol Sci, 283(1826). Abstract.  Author URL.  Full text.

2015

Sanders D, Kehoe R, Tiley K, Bennie J, Cruse D, Davies TW, Frank van Veen FJ, Gaston KJ (2015). Artificial nighttime light changes aphid-parasitoid population dynamics. Sci Rep, 5 Abstract.  Author URL.  Full text.
Sanders D, Kehoe R, van Veen FJF (2015). Experimental Evidence for the Population-Dynamic Mechanisms Underlying Extinction Cascades of Carnivores. Curr Biol, 25(23), 3106-3109. Abstract.  Author URL.
Sanders D, Vogel E, Knop E (2015). Individual and species-specific traits explain niche size and functional role in spiders as generalist predators. Journal of Animal Ecology, 84(1), 134-142. Abstract.
Sanders D, Vogel E, Knop E (2015). Individual and species-specific traits explain niche size and functional role in spiders as generalist predators. J Anim Ecol, 84(1), 134-142. Abstract.  Author URL.

2014

Sanders D, Jones CG, Thébault E, Bouma TJ, van der Heide T, van Belzen J, Barot S (2014). Integrating ecosystem engineering and food webs. Oikos
Sanders D, Jones CG, Thébault E, Bouma TJ, van der Heide T, van Belzen J, Barot S (2014). Integrating ecosystem engineering and food webs. Oikos, 123(5), 513-524. Abstract.
Knop E, Zünd J, Sanders D (2014). Interactive prey and predator diversity effects drive consumption rates. Oikos, 123(10), 1244-1249. Abstract.
Knop E, Zünd J, Sanders D (2014). Interactive prey and predator diversity effects drive consumption rates. Oikos Abstract.

2013

van Veen FJF, Sanders D (2013). Herbivore identity mediates the strength of trophic cascades on individual plants. ECOSPHERE, 4(5). Author URL.
Eggs B, Sanders D (2013). Herbivory in Spiders: the Importance of Pollen for Orb-Weavers. PLOS ONE, 8(11). Author URL.
Eggs B, Sanders D (2013). Herbivory in spiders: the importance of pollen for orb-weavers. PLoS ONE, 8(11). Abstract.
Sanders D, Sutter L, van Veen FJF (2013). The loss of indirect interactions leads to cascading extinctions of carnivores. Ecology Letters, 16(5), 664-669. Abstract.
Sanders D, Sutter L, van Veen FJF (2013). The loss of indirect interactions leads to cascading extinctions of carnivores. Ecol Lett, 16(5), 664-669. Abstract.  Author URL.

2012

Sanders D, Van Veen FJF (2012). Indirect commensalism promotes persistence of secondary consumer species. Biology Letters, 8(6), 960-963. Abstract.

2011

Sanders D, van Veen FJF (2011). Ecosystem engineering and predation: the multi-trophic impact of two ant species. Journal of Animal Ecology, 80(3), 569-576.
Sanders D, Schaefer M, Platner C, Griffiths GJK (2011). Intraguild interactions among generalist predator functional groups drive impact on herbivore and decomposer prey. Oikos, 120(3), 418-426. Abstract.
Sanders D, Entling MH (2011). Large variation of suction sampling efficiency depending on arthropod groups, species traits, and habitat properties. Entomologia Experimentalis et Applicata, 138(3), 234-243. Abstract.

2010

Sanders D, van Veen FJF (2010). The impact of an ant–aphid mutualism on the functional composition of the secondary parasitoid community. Ecological Entomology, 35(6), 704-710. Abstract.

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