1
|
Gerstle V, Bollinger E, Manfrin A, Pietz S, Kolbenschlag S, Feckler A, Entling MH, Brühl CA. Trophic effects of Bti-based mosquito control on two top predators in floodplain pond mesocosms. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024:10.1007/s11356-024-34124-w. [PMID: 38967849 DOI: 10.1007/s11356-024-34124-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Accepted: 06/21/2024] [Indexed: 07/06/2024]
Abstract
Chironomid (Diptera: Chironomidae) larvae play a key role in aquatic food webs as prey for predators like amphibian and dragonfly larvae. This trophic link may be disrupted by anthropogenic stressors such as Bacillus thuringiensis var. israelensis (Bti), a biocide widely used in mosquito control. In a companion study, we recorded a 41% reduction of non-target larval chironomids abundance in outdoor floodplain pond mesocosms (FPMs) treated with Bti. Therefore, we examined the diet of two top predators in the FPMs, larvae of the palmate newt (Salamandridae: Lissotriton helveticus) and dragonfly (Aeshnidae: predominantly Anax imperator), using bulk stable isotope analyses of carbon and nitrogen. Additionally, we determined neutral lipid fatty acids in newt larvae to assess diet-related effects on their physiological condition. We did not find any effects of Bti on the diet proportions of newt larvae and no significant effects on the fatty acid content. We observed a trend in Aeshnidae larvae from Bti-FPMs consuming a higher proportion of large prey (Aeshnidae, newt, damselfly larvae; ~42%), and similar parts of smaller prey (chironomid, mayfly, Libellulidae, and zooplankton), compared to controls. Our findings may suggest bottom-up effects of Bti on aquatic predators but should be further evaluated, for instance, by using compound-specific stable isotope analyses of fatty acids or metabarcoding approaches.
Collapse
Affiliation(s)
- Verena Gerstle
- Institute for Environmental Sciences, iES Landau, RPTU Kaiserslautern-Landau, Fortstraße 7, D-76829, Landau, Germany.
- Eußerthal Ecosystem Research Station, RPTU Kaiserslautern-Landau, Birkenthalstraße 13, D-76857, Eußerthal, Germany.
| | - Eric Bollinger
- Institute for Environmental Sciences, iES Landau, RPTU Kaiserslautern-Landau, Fortstraße 7, D-76829, Landau, Germany
| | - Alessandro Manfrin
- Institute for Environmental Sciences, iES Landau, RPTU Kaiserslautern-Landau, Fortstraße 7, D-76829, Landau, Germany
| | - Sebastian Pietz
- Institute for Environmental Sciences, iES Landau, RPTU Kaiserslautern-Landau, Fortstraße 7, D-76829, Landau, Germany
| | - Sara Kolbenschlag
- Institute for Environmental Sciences, iES Landau, RPTU Kaiserslautern-Landau, Fortstraße 7, D-76829, Landau, Germany
| | - Alexander Feckler
- Institute for Environmental Sciences, iES Landau, RPTU Kaiserslautern-Landau, Fortstraße 7, D-76829, Landau, Germany
- Eußerthal Ecosystem Research Station, RPTU Kaiserslautern-Landau, Birkenthalstraße 13, D-76857, Eußerthal, Germany
| | - Martin H Entling
- Institute for Environmental Sciences, iES Landau, RPTU Kaiserslautern-Landau, Fortstraße 7, D-76829, Landau, Germany
| | - Carsten A Brühl
- Institute for Environmental Sciences, iES Landau, RPTU Kaiserslautern-Landau, Fortstraße 7, D-76829, Landau, Germany
| |
Collapse
|
2
|
Röder N, Stoll VS, Jupke JF, Kolbenschlag S, Bundschuh M, Theißinger K, Schwenk K. How non-target chironomid communities respond to mosquito control: Integrating DNA metabarcoding and joint species distribution modelling. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 913:169735. [PMID: 38163597 DOI: 10.1016/j.scitotenv.2023.169735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 11/26/2023] [Accepted: 12/26/2023] [Indexed: 01/03/2024]
Abstract
The conservation and management of riparian ecosystems rely on understanding the ecological consequences of anthropogenic stressors that impact natural communities. In this context, studies investigating the effects of anthropogenic stressors require reliable methods capable of mapping the relationships between taxa occurrence or abundance and environmental predictors within a spatio-temporal framework. Here, we present an integrative approach using DNA metabarcoding and Hierarchical Modelling of Species Communities (HMSC) to unravel the intricate dynamics and resilience of chironomid communities exposed to Bacillus thuringiensis var. israelensis (Bti). Chironomid emergence was sampled from a total of 12 floodplain pond mesocosms, half of which received Bti treatment, during a 16-week period spanning spring and summer of 2020. Subsequently, we determined the community compositions of chironomids and examined their genus-specific responses to the Bti treatment, considering their phylogenetic affiliations and ecological traits of the larvae. Additionally, we investigated the impact of the Bti treatment on the body size distribution of emerging chironomids. Our study revealed consistent responses to Bti among different chironomid genera, indicating that neither phylogenetic affiliations nor larval feeding strategies significantly contributed to the observed patterns. Both taxonomic and genetic diversity were positively correlated with the number of emerged individuals. Furthermore, our findings demonstrated Bti-related effects on chironomid body size distribution, which could have relevant implications for size-selective terrestrial predators. Hence, our study highlights the value of employing a combination of DNA metabarcoding and HMSC to unravel the complex dynamics of Bti-related non-target effects on chironomid communities. The insights gained from this integrated framework contribute to our understanding of the ecological consequences of anthropogenic stressors and provide a foundation for informed decision-making regarding the conservation and management of riparian ecosystems.
Collapse
Affiliation(s)
- Nina Röder
- iES - Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany.
| | - V Sophie Stoll
- iES - Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany
| | - Jonathan F Jupke
- iES - Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany
| | - Sara Kolbenschlag
- iES - Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany
| | - Mirco Bundschuh
- iES - Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany; Department of Aquatic Science and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Kathrin Theißinger
- LOEWE Centre for Translational Biodiversity Genomics, Senckenberg Biodiversity and Climate Research Centre, Frankfurt am Main, Germany
| | - Klaus Schwenk
- iES - Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany; LOEWE Centre for Translational Biodiversity Genomics, Senckenberg Biodiversity and Climate Research Centre, Frankfurt am Main, Germany
| |
Collapse
|
3
|
Schulz R, Bundschuh M, Entling MH, Jungkunst HF, Lorke A, Schwenk K, Schäfer RB. A synthesis of anthropogenic stress effects on emergence-mediated aquatic-terrestrial linkages and riparian food webs. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 908:168186. [PMID: 37914130 DOI: 10.1016/j.scitotenv.2023.168186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 10/23/2023] [Accepted: 10/27/2023] [Indexed: 11/03/2023]
Abstract
Anthropogenic stress alters the linkage between aquatic and terrestrial ecosystems in various ways. Here, we review the contemporary literature on how alterations in aquatic systems through environmental pollution, invasive species and hydromorphological changes carry-over to terrestrial ecosystems and the food webs therein. We consider both the aquatic insect emergence and flooding as pathways through which stressors can propagate from the aquatic to the terrestrial system. We specifically synthesize and contextualize results on the roles of pollutants in the emergence pathway and their top-down consequences. Our review revealed that the emergence and flooding pathway are only considered in isolation and that the overall effects of invasive species or pollutants on food webs at the water-land interface require further attention. While very few recent studies looked at invasive species, a larger number of studies focused on metal transfer compared to pesticides, pharmaceuticals or PCBs, and multiple stress studies up to now left aquatic-terrestrial linkages unconsidered. Recent research on pollutants and emergence used aquatic-terrestrial mesocosms to elucidate the effects of aquatic stressors such as the mosquito control agent Bti, metals or pesticides to understand the effects on riparian spiders. Quality parameters, such as the structural and functional composition of emergent insect communities, the fatty acid profiles, yet also the composition of pollutants transferred to land prove to be important for the effects on riparian spiders. Process-based models including quality of emergence are useful to predict the resulting top-down directed food web effects in the terrestrial recipient ecosystem. In conclusion, we present and recommend a combination of empirical and modelling approaches in order to understand the complexity of aquatic-terrestrial stressor propagation and its spatial and temporal variation.
Collapse
Affiliation(s)
- Ralf Schulz
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany.
| | - Mirco Bundschuh
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany; Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Martin H Entling
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany
| | - Hermann F Jungkunst
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany
| | - Andreas Lorke
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany
| | - Klaus Schwenk
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany
| | - Ralf B Schäfer
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Landau, Germany
| |
Collapse
|
4
|
Bollinger E, Zubrod JP, Englert D, Graf N, Weisner O, Kolb S, Schäfer RB, Entling MH, Schulz R. The influence of season, hunting mode, and habitat specialization on riparian spiders as key predators in the aquatic-terrestrial linkage. Sci Rep 2023; 13:22950. [PMID: 38135811 PMCID: PMC10746743 DOI: 10.1038/s41598-023-50420-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 12/19/2023] [Indexed: 12/24/2023] Open
Abstract
Freshwater ecosystems subsidize riparian zones with high-quality nutrients via the emergence of aquatic insects. Spiders are dominant consumers of these insect subsidies. However, little is known about the variation of aquatic insect consumption across spiders of different hunting modes, habitat specializations, seasons, and systems. To explore this, we assembled a large stable isotope dataset (n > 1000) of aquatic versus terrestrial sources and six spider species over four points in time adjacent to a lotic and a lentic system. The spiders represent three hunting modes each consisting of a wetland specialist and a habitat generalist. We expected that specialists would feed more on aquatic prey than their generalist counterparts. Mixing models showed that spiders' diet consisted of 17-99% of aquatic sources, with no clear effect of habitat specialization. Averaged over the whole study period, web builders (WB) showed the highest proportions (78%) followed by ground hunters (GH, 42%) and vegetation hunters (VH, 31%). Consumption of aquatic prey was highest in June and August, which is most pronounced in GH and WBs, with the latter feeding almost entirely on aquatic sources during this period. Additionally, the elevated importance of high-quality lipids from aquatic origin during fall is indicated by elemental analyses pointing to an accumulation of lipids in October, which represent critical energy reserves during winter. Consequently, this study underlines the importance of aquatic prey irrespective of the habitat specialization of spiders. Furthermore, it suggests that energy flows vary substantially between spider hunting modes and seasons.
Collapse
Affiliation(s)
- Eric Bollinger
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Fortstraße 7, D-76829, Landau, Germany.
| | - Jochen P Zubrod
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Fortstraße 7, D-76829, Landau, Germany
- Zubrod Environmental Data Science, Ostring 24a, D-76829, Landau, Germany
| | - Dominic Englert
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Fortstraße 7, D-76829, Landau, Germany
| | - Nadin Graf
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Fortstraße 7, D-76829, Landau, Germany
| | - Oliver Weisner
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Fortstraße 7, D-76829, Landau, Germany
| | - Sebastian Kolb
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Fortstraße 7, D-76829, Landau, Germany
| | - Ralf B Schäfer
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Fortstraße 7, D-76829, Landau, Germany
| | - Martin H Entling
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Fortstraße 7, D-76829, Landau, Germany
| | - Ralf Schulz
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Fortstraße 7, D-76829, Landau, Germany
- Eußerthal Ecosystem Research Station, RPTU Kaiserslautern-Landau, Birkenthalstraße 13, D-76857, Eußerthal, Germany
| |
Collapse
|
5
|
Kolbenschlag S, Bollinger E, Gerstle V, Brühl CA, Entling MH, Schulz R, Bundschuh M. Impact across ecosystem boundaries - Does Bti application change quality and composition of the diet of riparian spiders? THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 873:162351. [PMID: 36822417 DOI: 10.1016/j.scitotenv.2023.162351] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/16/2023] [Accepted: 02/16/2023] [Indexed: 06/18/2023]
Abstract
Emerging aquatic insects link aquatic and adjacent terrestrial food webs by subsidizing terrestrial predators with high-quality prey. One of the main constituents of aquatic subsidy, the non-biting midges (Chironomidae), showed altered emergence dynamics in response to the mosquito control agent Bacillus thuringiensis var. israelensis (Bti). As riparian spiders depend on aquatic subsidy, they may be affected by such changes in prey availability. Thus, we conducted a field study in twelve floodplain pond mesocosms (FPMs), six were treated with Bti (2.88 × 109 ITU/ha, VectoBac WDG) three times, to investigate if the Bti-induced shift in chironomid emergence dynamics is reflected in their nutritional value and in the diet of riparian spiders. We measured the content of proteins, lipids, glycogen, and carbohydrates in emerged Chironomidae, and determined the stable isotope ratios of female Tetragnatha extensa, a web-building spider living in the riparian vegetation of the FPMs. We analysed the proportion of aquatic prey in spiders' diet, niche size, and trophic position. While the content of nutrients and thus the prey quality was not significantly altered by Bti, effects on the spiders' diet were observed. The trophic position of T. extensa from Bti-treated FPMs was lower compared to the control while the aquatic proportion was only minimally reduced. We assume that spiders fed more on terrestrial prey but also on other aquatic organisms such as Baetidae, whose emergence was unaffected by Bti. In contrast to the partly predaceous Chironomidae, consumption of aquatic and terrestrial primary consumers potentially explains the observed lower trophic position of spiders from Bti-treated FPMs. As prey organisms vary in their quality the suggested dietary shift could transfer previously observed effects of Bti to riparian spiders conceivably affecting their populations. Our results further support that anthropogenic stressors in aquatic ecosystems may translate to terrestrial predators through aquatic subsidy.
Collapse
Affiliation(s)
- Sara Kolbenschlag
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Fortstr. 7, D-76829 Landau, Germany
| | - Eric Bollinger
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Fortstr. 7, D-76829 Landau, Germany
| | - Verena Gerstle
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Fortstr. 7, D-76829 Landau, Germany
| | - Carsten A Brühl
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Fortstr. 7, D-76829 Landau, Germany
| | - Martin H Entling
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Fortstr. 7, D-76829 Landau, Germany
| | - Ralf Schulz
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Fortstr. 7, D-76829 Landau, Germany; Eußerthal Ecosystem Research Station, RPTU Kaiserslautern-Landau, Birkenthalstr. 13, D-76857 Eußerthal, Germany
| | - Mirco Bundschuh
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Fortstr. 7, D-76829 Landau, Germany; Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Lennart Hjelms väg 9, SWE-75007 Uppsala, Sweden.
| |
Collapse
|
6
|
Ganglo C, Mendoza-Lera C, Manfrin A, Bolpagni R, Gerstle V, Kolbenschlag S, Bollinger E, Schulz R, Lorke A. Does biocide treatment for mosquito control alter carbon dynamics in floodplain ponds? THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 872:161978. [PMID: 36739014 DOI: 10.1016/j.scitotenv.2023.161978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 01/29/2023] [Accepted: 01/29/2023] [Indexed: 06/18/2023]
Abstract
Shallow lentic aquatic ecosystems, such as ponds, are important repositories of carbon (C) and hotspots of C cycling and greenhouse gas emission. Tube-dwelling benthic invertebrates, such as chironomids, may be key players in C dynamics in these water bodies, yet their role in the C-budget at ecosystem level remains unclear. We tested whether a 41 % reduction in chironomid abundance after application of the mosquito control biocide Bacillus thuringiensis israelensis (Bti) had implications for the C-fluxes to the atmosphere, C-pools, and C-transformation (i.e. organic matter decomposition) in ponds. Data were collected over one year in the shallow, deep and riparian zones of 12 experimental floodplain pond mesocosms (FPMs), half of them treated with Bti. C-fluxes were measured as CO2 and CH4 emissions, atmospheric deposition, and emerging insects. C-pools were measured as dissolved inorganic and organic C in surface and porewater, sediment organic C, C in plant and in macroinvertebrate biomass. Despite seasonal variability, treated FPMs, for which higher CH4 emissions have been reported, showed a trend towards less dissolved organic C in porewater, while no effect was observed for all remaining components of the C-budget. We attribute the effect of Bti on the C-budget to the reduction in macroinvertebrates biomass, the increase in CH4 emissions, and the input of C from the Bti excipients. This finding suggests that changes in tube-dwelling macroinvertebrates have a weak influence on C cycling in ponds and confirms the existence of long-lasting effects of Bti on specific components of C-budgets.
Collapse
Affiliation(s)
- Caroline Ganglo
- RPTU Kaiserslautern-Landau, Institute for Environmental Sciences, Fortstr. 7, D-76829 Landau, Germany.
| | - Clara Mendoza-Lera
- RPTU Kaiserslautern-Landau, Institute for Environmental Sciences, Fortstr. 7, D-76829 Landau, Germany
| | - Alessandro Manfrin
- RPTU Kaiserslautern-Landau, Institute for Environmental Sciences, Fortstr. 7, D-76829 Landau, Germany
| | - Rossano Bolpagni
- University of Parma, Department of Chemistry, Life Sciences and Environmental Sustainability, Parco Area delle Scienze 33/A, 43124 Parma, Italy
| | - Verena Gerstle
- RPTU Kaiserslautern-Landau, Institute for Environmental Sciences, Fortstr. 7, D-76829 Landau, Germany
| | - Sara Kolbenschlag
- RPTU Kaiserslautern-Landau, Institute for Environmental Sciences, Fortstr. 7, D-76829 Landau, Germany
| | - Eric Bollinger
- RPTU Kaiserslautern-Landau, Institute for Environmental Sciences, Fortstr. 7, D-76829 Landau, Germany
| | - Ralf Schulz
- RPTU Kaiserslautern-Landau, Institute for Environmental Sciences, Fortstr. 7, D-76829 Landau, Germany
| | - Andreas Lorke
- RPTU Kaiserslautern-Landau, Institute for Environmental Sciences, Fortstr. 7, D-76829 Landau, Germany
| |
Collapse
|
7
|
Gerstle V, Solanki P, Manfrin A, Kolbenschlag S, Brühl CA. Stress Response of European Common Frog (Rana temporaria) Tadpoles to Bti Exposure in an Outdoor Pond Mesocosm. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2023; 110:70. [PMID: 36959482 PMCID: PMC10036417 DOI: 10.1007/s00128-023-03708-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 02/25/2023] [Indexed: 05/04/2023]
Abstract
The biocide Bacillus thuringiensis var. israelensis (Bti) is applied to wetlands to control nuisance by mosquitoes. Amphibians inhabiting these wetlands can be exposed to Bti multiple times, potentially inducing oxidative stress in developing tadpoles. For biochemical stress responses, ambient water temperature plays a key role. Therefore, we exposed tadpoles of the European common frog (Rana temporaria) three times to field-relevant doses of Bti in outdoor floodplain pond mesocosms (FPM) under natural environmental conditions. We sampled tadpoles after each Bti application over the course of a 51-day experiment (April to June 2021) and investigated the activity of the glutathione-S-transferase (GST) and protein carbonyl content as a measure for detoxification activity and oxidative damage. GST activity increased over the course of the experiment likely due to a general increase of water temperature. We did not observe an effect of Bti on either of the investigated biomarkers under natural ambient temperatures. However, Bti-induced effects may be concealed by the generally low water temperatures in our FPMs, particularly at the first application in April, when we expected the highest effect on the most sensitive early stage tadpoles. In light of the global climate change, temperature-related effects of pesticides and biocides on tadpoles should be carefully monitored - in particular since they are known as one of the factors driving the worldwide decline of amphibian populations.
Collapse
Affiliation(s)
- Verena Gerstle
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Fortstraße 7, D-76829, Landau, Germany.
| | - Priyanka Solanki
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Fortstraße 7, D-76829, Landau, Germany
| | - Alessandro Manfrin
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Fortstraße 7, D-76829, Landau, Germany
| | - Sara Kolbenschlag
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Fortstraße 7, D-76829, Landau, Germany
| | - Carsten A Brühl
- iES Landau, Institute for Environmental Sciences, RPTU Kaiserslautern-Landau, Fortstraße 7, D-76829, Landau, Germany
| |
Collapse
|
8
|
Kolbenschlag S, Gerstle V, Eberhardt J, Bollinger E, Schulz R, Brühl CA, Bundschuh M. A temporal perspective on aquatic subsidy: Bti affects emergence of Chironomidae. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 250:114503. [PMID: 36610297 DOI: 10.1016/j.ecoenv.2023.114503] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 11/05/2022] [Accepted: 01/02/2023] [Indexed: 06/17/2023]
Abstract
Emerging aquatic insects serve as one link between aquatic and adjacent riparian food webs via the flux of energy and nutrients. These insects provide high-quality subsidy to terrestrial predators. Thus, any disturbance of emergence processes may cascade to higher trophic levels and lead to effects across ecosystem boundaries. One stressor with potential impact on non-target aquatic insects, especially on non-biting midges (Diptera: Chironomidae), is the widely used mosquito control agent Bacillus thuringiensis var. israelensis (Bti). In a field experiment, we investigated emerging insect communities from Bti-treated (three applications, maximum field rate) and control floodplain pond mesocosms (FPMs) over 3.5 months for changes in their composition, diversity as well as the emergence dynamics and the individual weight of emerged aquatic insects over time. Bti treatments altered community compositions over the entire study duration - an effect mainly attributed to an earlier (∼10 days) and reduced (∼26%) peak in the emergence of Chironomidae, the dominant family (88% of collected individuals). The most reasonable explanation for this significant alteration is less resource competition caused by a decrease in chironomid larval density due to lethal effects of Bti. This is supported by the higher individual weight of Chironomidae emerging from treated FPMs (∼21%) during Bti application (April - May). A temporal shift in the emergence dynamics can cause changes in the availability of prey in linked terrestrial ecosystems. Consequently, terrestrial predators may be affected by a lack of appropriate prey leading to bottom-up and top-down effects in terrestrial food webs. This study indicates the importance of a responsible and elaborated use of Bti and additionally, highlights the need to include a temporal perspective in evaluations of stressors in aquatic-terrestrial meta-ecosystems.
Collapse
Affiliation(s)
- Sara Kolbenschlag
- iES Landau, Institute for Environmental Sciences, University of Kaiserslautern-Landau (RPTU), Fortstr. 7, D-76829 Landau, Germany
| | - Verena Gerstle
- iES Landau, Institute for Environmental Sciences, University of Kaiserslautern-Landau (RPTU), Fortstr. 7, D-76829 Landau, Germany
| | - Julian Eberhardt
- iES Landau, Institute for Environmental Sciences, University of Kaiserslautern-Landau (RPTU), Fortstr. 7, D-76829 Landau, Germany
| | - Eric Bollinger
- iES Landau, Institute for Environmental Sciences, University of Kaiserslautern-Landau (RPTU), Fortstr. 7, D-76829 Landau, Germany
| | - Ralf Schulz
- iES Landau, Institute for Environmental Sciences, University of Kaiserslautern-Landau (RPTU), Fortstr. 7, D-76829 Landau, Germany; Eußerthal Ecosystem Research Station, University of Kaiserslautern-Landau (RPTU), Birkenthalstr. 13, D-76857 Eußerthal, Germany
| | - Carsten A Brühl
- iES Landau, Institute for Environmental Sciences, University of Kaiserslautern-Landau (RPTU), Fortstr. 7, D-76829 Landau, Germany
| | - Mirco Bundschuh
- iES Landau, Institute for Environmental Sciences, University of Kaiserslautern-Landau (RPTU), Fortstr. 7, D-76829 Landau, Germany; Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Lennart Hjelms väg 9, SWE-75007 Uppsala, Sweden.
| |
Collapse
|
9
|
Gerstle V, Manfrin A, Kolbenschlag S, Gerken M, Islam ASMMU, Entling MH, Bundschuh M, Brühl CA. Benthic macroinvertebrate community shifts based on Bti-induced chironomid reduction also decrease Odonata emergence. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 316:120488. [PMID: 36306884 DOI: 10.1016/j.envpol.2022.120488] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 10/15/2022] [Accepted: 10/17/2022] [Indexed: 06/16/2023]
Abstract
Chironomid larvae (Diptera: Chironomidae) often dominate aquatic macroinvertebrate communities and are a key food source for many aquatic predators, such as dragonfly and damselfly larvae (Odonata). Changes in aquatic macroinvertebrate communities may propagate through terrestrial food webs via altered insect emergence. Bacillus thuringiensis israelensis (Bti)-based larvicides are widely used in mosquito control but can also reduce the abundance of non-biting chironomid larvae. We applied the maximum field rate of Bti used in mosquito control three times to six mesocosms in a replicated floodplain pond mesocosm (FPM) system in spring for two consecutive years, while the remaining six FPMs were untreated. Three weeks after the third Bti application in the first year, we recorded on average a 41% reduction of chironomid larvae in Bti-treated FPMs compared to untreated FPMs and a shift in benthic macroinvertebrate community composition driven by the reduced number of chironomid, Libellulidae and Coenagrionidae larvae (Odonata). Additionally, the number of emerging Libellulidae (estimated by sampling of exuviae in the second year) was reduced by 54% in Bti-treated FPMs. Since Odonata larvae are not directly susceptible to Bti, our results suggest indirect effects due to reduced prey availability (i.e., chironomid larvae) or increased intraguild predation. As Libellulidae include species of conservation concern, the necessity of Bti applications to their habitats, e.g. floodplains, should be carefully evaluated.
Collapse
Affiliation(s)
- Verena Gerstle
- Institute for Environmental Sciences, iES Landau, University of Koblenz-Landau, Fortstraße 7, D-76829, Landau, Germany.
| | - Alessandro Manfrin
- Institute for Environmental Sciences, iES Landau, University of Koblenz-Landau, Fortstraße 7, D-76829, Landau, Germany
| | - Sara Kolbenschlag
- Institute for Environmental Sciences, iES Landau, University of Koblenz-Landau, Fortstraße 7, D-76829, Landau, Germany
| | - Maximilian Gerken
- Institute for Environmental Sciences, iES Landau, University of Koblenz-Landau, Fortstraße 7, D-76829, Landau, Germany; Eußerthal Ecosystem Research Station, University of Koblenz-Landau, Birkenthalstraße 13, D-76857, Eußerthal, Germany
| | - A S M Mufachcher Ul Islam
- Institute for Environmental Sciences, iES Landau, University of Koblenz-Landau, Fortstraße 7, D-76829, Landau, Germany
| | - Martin H Entling
- Institute for Environmental Sciences, iES Landau, University of Koblenz-Landau, Fortstraße 7, D-76829, Landau, Germany
| | - Mirco Bundschuh
- Institute for Environmental Sciences, iES Landau, University of Koblenz-Landau, Fortstraße 7, D-76829, Landau, Germany; Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Lennart Hjelms väg 9, SWE-75007, Uppsala, Sweden
| | - Carsten A Brühl
- Institute for Environmental Sciences, iES Landau, University of Koblenz-Landau, Fortstraße 7, D-76829, Landau, Germany
| |
Collapse
|