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Schmidt RC, Woods T, Nyingi WD. Drivers of species richness and beta diversity of fishes in an Afrotropical intermittent river system. Ecol Evol 2022; 12:e9659. [PMID: 36590335 PMCID: PMC9797352 DOI: 10.1002/ece3.9659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 12/03/2022] [Accepted: 12/06/2022] [Indexed: 12/30/2022] Open
Abstract
Tropical freshwater ecosystems are some of the most threatened systems yet remain understudied relative to temperate systems. Here, we look at the drivers of community structure of fishes in a tropical and intermittent system in central Kenya. We conducted monthly samples within the upper Northern Ewaso Ng'iro to assess variation in community composition and abiotic characteristics. We analyzed species richness along the longitudinal gradient, computed beta diversity within the system, relative contributions of each site, and partitioned beta diversity metrics into nestedness and turnover components. We found that, similar to temperate intermittent systems, species richness varied along the longitudinal gradient, nestedness contributions to beta diversity exceeded those of turnover, and environmental and spatial variables determined patterns of beta diversity. Sites at the highest and lowest ends of the species richness gradient showed the highest contributions to beta diversity, suggesting sites important for preservation or restoration initiatives, respectively. With ongoing water extraction and conflict over resources throughout the region, this study highlights the need for further investigations of the effects of multiple stressors on biodiversity patterns and ecosystem functioning in tropical stream communities.
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Affiliation(s)
- Ray C. Schmidt
- Biology DepartmentRandolph‐Macon CollegeAshlandVirginiaUSA,Division of FishesNational Museum of Natural HistoryWashingtonDistrict of ColumbiaUSA
| | - Taylor Woods
- Department of Ecology and Evolutionary BiologyThe University of TennesseeKnoxvilleTennesseeUSA
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Raburu PO, Masese FO, Mwasi BN. Low diversity of fishes in high elevation Afrotromontane streams renders them unsuitable for biomonitoring. Afr J Ecol 2022. [DOI: 10.1111/aje.13056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Phillip O. Raburu
- Division for Research and Extension University of Eldoret Eldoret Kenya
- Department of Fisheries & Aquatic Science University of Eldoret Eldoret Kenya
| | - Frank O. Masese
- Department of Fisheries & Aquatic Science University of Eldoret Eldoret Kenya
| | - Benjamin N. Mwasi
- Department of Environmental Biology & Health University of Eldoret Eldoret Kenya
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Caldwell TJ, Chandra S, Feher K, Simmons JB, Hogan Z. Ecosystem response to earlier ice break-up date: Climate-driven changes to water temperature, lake-habitat-specific production, and trout habitat and resource use. GLOBAL CHANGE BIOLOGY 2020; 26:5475-5491. [PMID: 32602183 DOI: 10.1111/gcb.15258] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 05/19/2020] [Accepted: 06/06/2020] [Indexed: 06/11/2023]
Abstract
Climate warming has yielded earlier ice break-up dates in recent decades for lakes leading to water temperature increases, altered habitat, and both increases and decreases to ecosystem productivity. Within lakes, the effect of climate warming on secondary production in littoral and pelagic habitats remains unclear. The intersection of changing habitat productivity and warming water temperatures on salmonids is important for understanding how climate warming will impact mountain ecosystems. We develop and test a conceptual model that expresses how earlier ice break-up dates influence within lake habitat production, water temperatures and the habitat utilized by, resources obtained and behavior of salmonids in a mountain lake. We measured zoobenthic and zooplankton production from the littoral and pelagic habitats, thermal conditions, and the habitat use, resource use, and fitness of Brook Trout (Salvelinus fontinalis). We show that earlier ice break-up conditions created a "resource-rich" littoral-benthic habitat with increases in zoobenthic production compared to the pelagic habitat which decreased in zooplankton production. Despite the increases in littoral-benthic food resources, trout did not utilize littoral habitat or zoobenthic resources due to longer durations of warm water temperatures in the littoral zone. In addition, 87% of their resources were supported by the pelagic habitat during periods with earlier ice break-up when pelagic resources were least abundant. The decreased reliance on littoral-benthic resources during earlier ice break-up caused reduced fitness (mean reduction of 12 g) to trout. Our data show that changes to ice break-up drive multi-directional results for resource production within lake habitats and increase the duration of warmer water temperatures in food-rich littoral habitats. The increased duration of warmer littoral water temperatures reduces the use of energetically efficient habitats culminating in decreased trout fitness.
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Affiliation(s)
- Timothy J Caldwell
- Ecology, Evolution and Conservation Biology Graduate Program, University of Nevada, Reno, NV, USA
- Department of Biology, College of Science, University of Nevada, Reno, NV, USA
| | - Sudeep Chandra
- Ecology, Evolution and Conservation Biology Graduate Program, University of Nevada, Reno, NV, USA
- Department of Biology, College of Science, University of Nevada, Reno, NV, USA
- Global Water Center, University of Nevada, Reno, NV, USA
| | - Karly Feher
- Department of Biology, College of Science, University of Nevada, Reno, NV, USA
| | - James B Simmons
- Ecology, Evolution and Conservation Biology Graduate Program, University of Nevada, Reno, NV, USA
- Department of Biology, College of Science, University of Nevada, Reno, NV, USA
| | - Zeb Hogan
- Department of Biology, College of Science, University of Nevada, Reno, NV, USA
- Global Water Center, University of Nevada, Reno, NV, USA
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Lo M, Reed J, Castello L, Steel EA, Frimpong EA, Ickowitz A. The Influence of Forests on Freshwater Fish in the Tropics: A Systematic Review. Bioscience 2020; 70:404-414. [PMID: 32440023 PMCID: PMC7231604 DOI: 10.1093/biosci/biaa021] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Tropical forests influence freshwater fish through multiple pathways, only some of which are well documented. We systematically reviewed the literature to assess the current state of knowledge on forests and freshwater fish in the tropics. The existing evidence is mostly concentrated in the neotropics. The majority of studies provided evidence that fish diversity was higher where there was more forest cover; this was related to the greater heterogeneity of resources in forested environments that could support a wider range of species. Studies quantifying fish abundance (or biomass) showed mixed relationships with forest cover, depending on species-specific habitat preferences. We identify the key challenges limiting our current understanding of the forest-fish nexus and provide recommendations for future research to address these knowledge gaps. A clear understanding of the functional pathways in forest-freshwater ecosystems can improve evidence-based policy development concerned with deforestation, biodiversity conservation, and food insecurity in the tropics.
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Affiliation(s)
- Michaela Lo
- Center for International Forestry Research, Bogor, Indonesia
| | - James Reed
- Center for International Forestry Research, Bogor, Indonesia
| | - Leandro Castello
- Department of Fish and Wildlife Conservation, Virginia Polytechnic Institute and State University, Blacksburg, Virginia
| | - E Ashley Steel
- Food and Agricultural Organization, United Nations, Rome, Italy
| | | | - Amy Ickowitz
- Center for International Forestry Research, Bogor, Indonesia
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