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Bulmer RH, Stephenson F, Lohrer AM, Lundquist CJ, Madarasz-Smith A, Pilditch CA, Thrush SF, Hewitt JE. Informing the management of multiple stressors on estuarine ecosystems using an expert-based Bayesian Network model. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 301:113576. [PMID: 34597946 DOI: 10.1016/j.jenvman.2021.113576] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Revised: 08/10/2021] [Accepted: 08/19/2021] [Indexed: 05/09/2023]
Abstract
The approach of applying stressor load limits or thresholds to aid estuarine management is being explored in many global case studies. However, there is growing concern regarding the influence of multiple stressors and their cumulative effects on the functioning of estuarine ecosystems due to the considerable uncertainty around stressor interactions. Recognising that empirical data limitations hinder parameterisation of detailed models of estuarine ecosystem responses to multiple stressors (suspended sediment, sediment mud and metal content, and nitrogen inputs), an expert driven Bayesian network (BN) was developed and validated. Overall, trends in estuarine condition predicted by the BN model were well supported by field observations, including results that were markedly higher than random (71-84% concordance), providing confidence in the overall model dynamics. The general BN framework was then applied to a case study estuary to demonstrate the model's utility for informing management decisions. Results indicated that reductions in suspended sediment loading were likely to result in improvements in estuarine condition, which was further improved by reductions in sediment mud and metal content, with an increased likelihood of high abundance of ecological communities relative to baseline conditions. Notably, reductions in suspended sediment were also associated with an increased probability of high nuisance macroalgae and phytoplankton if nutrient loading was not also reduced (associated with increased water column light penetration). Our results highlight that if stressor limit setting is to be implemented, limits must incorporate ecosystem responses to cumulative stressors, consider the present and desired future condition of the estuary of interest, and account for the likelihood of unexpected ecological outcomes regardless of whether the experts (or empirical data) suggest a threshold has or has not been triggered.
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Affiliation(s)
- R H Bulmer
- National Institute of Water & Atmospheric Research, New Zealand.
| | - F Stephenson
- National Institute of Water & Atmospheric Research, New Zealand
| | - A M Lohrer
- National Institute of Water & Atmospheric Research, New Zealand
| | - C J Lundquist
- National Institute of Water & Atmospheric Research, New Zealand; University of Auckland, New Zealand
| | | | | | | | - J E Hewitt
- National Institute of Water & Atmospheric Research, New Zealand; University of Auckland, New Zealand
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Tobias ZJC, Fowler AE, Blakeslee AMH, Darling JA, Torchin ME, Miller AW, Ruiz GM, Tepolt CK. Invasion history shapes host transcriptomic response to a body-snatching parasite. Mol Ecol 2021; 30:4321-4337. [PMID: 34162013 PMCID: PMC10128110 DOI: 10.1111/mec.16038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 05/27/2021] [Accepted: 06/11/2021] [Indexed: 01/04/2023]
Abstract
By shuffling biogeographical distributions, biological invasions can both disrupt long-standing associations between hosts and parasites and establish new ones. This creates natural experiments with which to study the ecology and evolution of host-parasite interactions. In estuaries of the Gulf of Mexico, the white-fingered mud crab (Rhithropanopeus harrisii) is infected by a native parasitic barnacle, Loxothylacus panopaei (Rhizocephala), which manipulates host physiology and behaviour. In the 1960s, L. panopaei was introduced to the Chesapeake Bay and has since expanded along the southeastern Atlantic coast, while host populations in the northeast have so far been spared. We use this system to test the host's transcriptomic response to parasitic infection and investigate how this response varies with the parasite's invasion history, comparing populations representing (i) long-term sympatry between host and parasite, (ii) new associations where the parasite has invaded during the last 60 years and (iii) naïve hosts without prior exposure. A comparison of parasitized and control crabs revealed a core response, with widespread downregulation of transcripts involved in immunity and moulting. The transcriptional response differed between hosts from the parasite's native range and where it is absent, consistent with previous observations of increased susceptibility in populations lacking exposure to the parasite. Crabs from the parasite's introduced range, where prevalence is highest, displayed the most dissimilar response, possibly reflecting immune priming. These results provide molecular evidence for parasitic manipulation of host phenotype and the role of gene regulation in mediating host-parasite interactions.
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Affiliation(s)
- Zachary J. C. Tobias
- MIT-WHOI Joint Program in Oceanography/Applied Ocean Science and Engineering, Cambridge and Woods Hole, MA, USA
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Amy E. Fowler
- Department of Environmental Science and Policy, George Mason University, Fairfax, VA, USA
| | | | - John A. Darling
- National Exposure Research Laboratory, US Environmental Protection Agency, Research Triangle Park, NC, USA
| | - Mark E. Torchin
- Smithsonian Tropical Research Institute, Balboa, Ancon, Republic of Panama
| | | | - Gregory M. Ruiz
- Smithsonian Environmental Research, Center, Edgewater, MD, USA
| | - Carolyn K. Tepolt
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
- Smithsonian Environmental Research, Center, Edgewater, MD, USA
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Population genetics of estuary and reservoir populations of Harris mud crabs, Rhithropanopeus harrisii, in Texas and Oklahoma. Biol Invasions 2021. [DOI: 10.1007/s10530-021-02580-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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