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Abonyi A, Fornberg J, Rasconi S, Ptacnik R, Kainz MJ, Lafferty KD. The chytrid insurance hypothesis: integrating parasitic chytrids into a biodiversity-ecosystem functioning framework for phytoplankton-zooplankton population dynamics. Oecologia 2024; 204:279-288. [PMID: 38366067 PMCID: PMC10907492 DOI: 10.1007/s00442-024-05519-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 01/28/2024] [Indexed: 02/18/2024]
Abstract
In temperate lakes, eutrophication and warm temperatures can promote cyanobacteria blooms that reduce water quality and impair food-chain support. Although parasitic chytrids of phytoplankton might compete with zooplankton, they also indirectly support zooplankton populations through the "mycoloop", which helps move energy and essential dietary molecules from inedible phytoplankton to zooplankton. Here, we consider how the mycoloop might fit into the biodiversity-ecosystem functioning (BEF) framework. BEF considers how more diverse communities can benefit ecosystem functions like zooplankton production. Chytrids are themselves part of pelagic food webs and they directly contribute to zooplankton diets through spore production and by increasing host edibility. The additional way that chytrids might support BEF is if they engage in "kill-the-winner" dynamics. In contrast to grazers, which result in "eat-the-edible" dynamics, kill-the-winner dynamics can occur for host-specific infectious diseases that control the abundance of dominant (in this case inedible) hosts and thus limit the competitive exclusion of poorer (in this case edible) competitors. Thus, if phytoplankton diversity provides functions, and chytrids support algal diversity, chytrids could indirectly favour edible phytoplankton. All three mechanisms are linked to diversity and therefore provide some "insurance" for zooplankton production against the impacts of eutrophication and warming. In our perspective piece, we explore evidence for the chytrid insurance hypothesis, identify exceptions and knowledge gaps, and outline future research directions.
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Affiliation(s)
- András Abonyi
- WasserCluster Lunz-Biologische Station GmbH, Dr. Carl Kupelwieser Promenade 5, 3293, Lunz Am See, Austria.
- MTA-ÖK Lendület "Momentum" Fluvial Ecology Research Group, Institute of Aquatic Ecology, HUN-REN Centre for Ecological Research, Karolina Street 29, 1113, Budapest, Hungary.
| | - Johanna Fornberg
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Serena Rasconi
- Université Savoie Mont Blanc, INRAE, CARRTEL, 74200, Thonon-Les-Bains, France
| | - Robert Ptacnik
- WasserCluster Lunz-Biologische Station GmbH, Dr. Carl Kupelwieser Promenade 5, 3293, Lunz Am See, Austria
| | - Martin J Kainz
- WasserCluster Lunz-Biologische Station GmbH, Dr. Carl Kupelwieser Promenade 5, 3293, Lunz Am See, Austria
- Donau-Universität Krems, Dr. Karl Dorrek Straße 30, 3500, Krems, Austria
| | - Kevin D Lafferty
- U.S. Geological Survey, Western Ecological Research Center, at Marine Science Institute, UC Santa Barbara, Santa Barbara, CA, 93106-6150, USA
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Sheu JT, Lu JFR. The spillover effect of National Health Insurance on household consumption patterns: evidence from a natural experiment in Taiwan. Soc Sci Med 2014; 111:41-9. [PMID: 24747377 DOI: 10.1016/j.socscimed.2014.04.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2013] [Revised: 04/05/2014] [Accepted: 04/07/2014] [Indexed: 11/19/2022]
Abstract
While providing financial risk protection was one of the major aims of introducing a National Health Insurance (NHI) program in Taiwan in 1995, one may also wonder how the households may exploit resources freed up and available to them as a result of reduced exposure to risk due to health insurance. This paper aims at studying and evaluating the impact of social insurance on these differing household consumption patterns. A differences-in-differences estimation model was applied to a sample of 17,899 households from the 1993-2000 Taiwan Survey of Family Income and Expenditure to assess the NHI's impact. This effect was evaluated by the changes in the proportion of the consumption expenditure devoted to medical items and non-medical items in the post-NHI period (1996-2000) compared to the pre-NHI period (1993-1994). Our study found that spending related to the improvement of housing conditions (rental and water bills) had the most significant increase, 1.87% (in the share). Furthermore, examining the NHI impact across socioeconomic status (SES) strata (in terms of income and education levels), our study found that households with the lowest SES experienced the largest increase in spending share (2.16%) for rental and water bills, and the least drop (0.64%) on education items. Recognizing how households can exploit the potential benefits associated with NHI provision could enable the government to devise specific policy tools to facilitate better targeting of investment decisions with limited resources available for less well-off households.
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Affiliation(s)
- Ji-Tian Sheu
- Department of Health Care Management, College of Management, Chang Gung University, Taiwan.
| | - Jui-Fen Rachel Lu
- Department of Health Care Management, College of Management, Chang Gung University, Taiwan.
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