"Wetlands"

Gbewaa, Suleman B.; Oppong, S. Kobby; Horne, Brian D.; Tehoda, Paul; Petrozzi, Fabio; Dendi, Daniele; Akani, Godfrey C.; Di Vittorio, Massimiliano; Ajong, Stephanie N.; Pacini, Nic; Fa, Julia E.; Luiselli, Luca

doi: 10.1007/s13157-021-01459-wpmid: N/A

Despite increasing pressures on freshwater resources worldwide, and the threatened status of most freshwater turtles, there is still limited knowledge of habitat use and niche partitioning in Afrotropical freshwater turtle communities. In this study, we describe habitat associations, community diversity, and temporal patterns of occurrence of freshwater turtle species in the Dahomey Gap ecoregion of Ghana (West Africa). We gathered data from 13 sites in central Ghana and along the Sene Arm of Lake Volta in the Digya National Park (Bono East Region). We employed opportunistic short-term surveys (at seven sites) together with longer-term (six-months duration) standardized evaluations of turtle presence and numbers in different habitats (at six sites). Overall, a total of 210 turtle individuals of four species (Trionyx triunguis, Cyclanorbis senegalensis, Pelomedusa sp. and Pelusios castaneus) were recorded; precise capture sites and habitat type were recorded for 139 individuals, but the 71 individuals observed in marketplaces were not considered in our analyses. At a local scale, we observed three sympatric species in various study sites. In each of these sites, the dominant species was either C. senegalensis or Pelomedusa sp., with the latter species being more abundant in temporary waterbodies and C. senegalensis more numerous in permanent ones. A Multiple Correspondence Analysis suggested that, in permanent waterbodies all species were associated with similar physical habitat variables. In a Canonical Correspondence Analysis, we showed that the density of herbaceous emergent vegetation was more important for P. castaneus than for C. senegalensis. Comparisons of diversity metrics between our study sites and previous studies revealed that turtle community composition was similar across savannah sites.

Carhart, Alicia M.; Kalas, John E.; Rogala, James T.; Rohweder, Jason J.; Drake, Deanne C.; Houser, Jeffrey N.

doi: 10.1007/s13157-021-01454-1pmid: N/A

Aquatic vegetation is a key component of large floodplain river ecosystems. In the Upper Mississippi River System (UMRS), there is a long-standing interest in restoring aquatic vegetation in areas where it has declined or disappeared. To better understand what constrains vegetation distribution in large river ecosystems and inform ongoing efforts to restore submersed aquatic vegetation (SAV), we delineated areas in ~1200 river km of the UMRS where the combined effects of water clarity, water level fluctuation, and bathymetry appeared suitable for establishment and persistence of SAV based on a 22-year dataset for total suspended solids (TSS), water surface elevation, and aquatic vegetation distribution. We found a large increase in suitable area downstream from a large natural riverine lake near the northern end of the UMRS (river km 1230) that functions as a sink for suspended material. Downstream from river km 895, there was much less suitable area due to decreased water clarity from tributary input of suspended material, changes in river geomorphology, and increased water level fluctuation. A hypothetical scenario of 75% reduction in TSS resulted in only minor increases in suitable area in the southern portion of the UMRS, indicating limitations by water level fluctuation and/or bathymetry (i.e., limited shallow area). These results improve our understanding of the structure and function of large river systems by illustrating how water clarity, fluctuations in water level, and river geomorphology interact to create complex spatial patterns in habitat suitability for aquatic species and may help to identify locations most and least likely to benefit from management and restoration efforts.

Wang, Rui; Wang, Miao; Wang, Jing; Yao, Jiahe; Li, Xinwei; Lin, Yinghua; Du, Fang K.

doi: 10.1007/s13157-021-01455-0pmid: N/A

Soil bacteria play important roles in regulating biogeochemical cycles and maintaining ecosystem function. However, our knowledge of patterns and driving factors of permafrost microbial communities under typical alpine meadow habitats with different vegetation communities is limited. We analyzed the relationship between soil bacterial community and changes of environmental factors among four habitats (swamp wetland, swamp meadow, meadow, and mature meadow) with different dominant vegetation types on the eastern edge of Qinghai-Tibetan, China. The results showed that though the bacterial community composition among four habitats was similar, the proportions of dominant species and the bacterial biomarkers in each habitat were unique. The bacterial community structure of mature meadow was obviously distinct from the other three habitats, which derived from the significant difference in soil nutrients and shoot biomass compared to the others. Specifically, distance-based redundancy analysis showed that soil total nitrogen and soil water content explained the greatest difference in bacterial structures, followed by soil temperature, pH and shoot biomass. Different habitats formed various network patterns, which showed more significant connections in swamp meadow and meadow than swamp wetland and mature meadow. Rhizomicrobium, Pseudonocardia, Geobacter, Bryobacter, Syntrophorhabdus, Nitrospira, Solirubrobacter and Pedomicrobium were the most important keystone genera in the bacterial co-occurrence networks.

Gallagher, John Barry; Prahalad, Vishnu; Aalders, John

doi: 10.1007/s13157-021-01460-3pmid: N/A

Total organic carbon (TOC) sediment stocks as a CO2 mitigation service require exclusion of allochthonous black (BC) and particulate inorganic carbon corrected for water–atmospheric equilibrium (PICeq). For the first time, we address this bias for a temperate salt marsh and a coastal tropical seagrass in BC hotspots that represent two different blue carbon ecosystems of Malaysia and Australia. Seagrass TOC stocks were similar to the salt marshes with soil depths < 1 m (59.3 ± 11.3 and 74.9 ± 18.9 MgC ha− 1, CI 95 % respectively). Both ecosystems showed larger BC constraints than did their pristine counterparts. However, the seagrass meadows’ mitigation services were largely constrained by both higher BC/TOC and PICeq/TOC fractions (38.0 % ± 6.6 and 43.4 % ± 5.9 %, CI 95 %) and salt marshes around a third (22 % ± 10.2 and 6.0 % ± 3.1 % CI 95 %). The results provide useful data from underrepresented regions, and, reiterates the need to consider both BC and PIC for more reliable blue carbon mitigation assessments to ensure that greenhouse gas emitters do not exceed the ecosystems’ capacity.

Otte, Marinus L.; Fang, Wei-Ta; Jiang, Ming

doi: 10.1007/s13157-021-01447-0pmid: N/A

A Correction to this paper has been published: https://doi.org/https://doi.org/10.1007/s13157-021-01447-0

Ashby✉, Mark Andrew; Heinemeyer, Andreas

doi: 10.1007/s13157-021-01400-1pmid: N/A

Despite substantial contrary evidence, there has been a growing tendency to present prescribed vegetation burning as a management practice that is always damaging to peatland ecosystems in the UK. This is exemplified by the “Burning and Peatlands” position statement published by the International Union for Conservation of Nature UK Peatland Programme. Indeed, while we strongly agree with several of the statements made within this position statement, it also contains a series of unverified assertions and misleading arguments that seemingly serve to simplify the narrative and paint prescribed burning as a wholly damaging peatland management tool. Given that this position statement is published by one of the UK’s most prominent peatland conservation organisations, it is likely to be consulted when debating upland land use policy. Therefore, for the benefit of policymakers, we provide a point-by-point critical review of the “Burning and Peatlands” position statement. We also discuss several further points for researchers and policymakers to consider that are consistently ignored by those attempting to simplify the narrative about prescribed burning. Our aim in producing this discussion paper is to encourage the research and policy community to move towards an evidence-based position about prescribed burning impacts on UK peatlands.

King, Sammy L.; Laubhan, Murray K.; Tashjian, Paul; Vradenburg, John; Fredrickson, Leigh

doi: 10.1007/s13157-021-01449-ypmid: N/A

Water is essential for wetland function and sustaining migratory networks for wetland wildlife across broad landscapes. Groundwater declines and surface flow reductions that impact aquatic and wetland organisms are common in the western U.S. and increasingly in the eastern U.S. Agriculture is the largest consumptive water use in the U.S. and understanding economic incentives of water-use practices and the legal context of water rights is foundational to identifying meaningful water solutions that benefit all sectors of society. In this paper, we provide a brief overview of water rights in the U.S. and synthesize the literature to provide a broad overview of how federal farm policy influences water-use decisions. We conclude that the ultimate cause of many water-use conflicts is an inefficient farm economy that is driven by several proximate factors, of which outdated water laws and subsidies that encourage increased water use are among the most important. Development of multi-scale water budgets to assess project impacts and by working more intensively at local watershed and aquifer scales may improve conservation efforts. Finally, detailed analyses to understand the impacts of specific federal policies on agricultural water use may enhance water conservation efforts, facilitate long-term food and water security, and provide greater protection for wetland and aquatic resources.

Leonard, Emily E.; Mast, Amanda M.; Hawkins, Charles P.; Kettenring, Karin M.

doi: 10.1007/s13157-021-01446-1pmid: N/A

Wetlands provide essential habitat for shorebirds, songbirds, and waterfowl. Invasive species can disrupt trophic interactions within wetlands by altering the arthropod assemblages on which birds rely. An invasive grass species, Phragmites australis (common reed), has invaded wetlands across North America, including those surrounding the Great Salt Lake, Utah, U.S.A. Phragmites outcompetes native vegetation and alters habitat for resident and migratory birds, yet how Phragmites affects arthropod assemblages is unclear. To address these knowledge gaps, this study investigated how arthropod assemblages differ between native and invasive vegetation in Great Salt Lake wetlands. We examined the arthropod assemblages found within three native habitats as well as in Phragmites-invaded areas. There were few differences in arthropod assemblages between Phragmites and two native habitats (hardstem bulrush, Schoenoplectus acutus and alkali bulrush, Bolboschoenus maritimus). Arthropod assemblages differed between Phragmites and the native Salicornia rubra (pickleweed), which differed markedly from the other plant species in structure, biomass, and related site conditions. Identifying how arthropods interact with Phragmites and native vegetation is critical to recognizing how to effectively manage wetlands for bird habitat. By gaining an understanding of these relationships, arthropod biomass, abundance, diversity, and assemblage composition could serve as assessment metrics for determining wetland management success.

Jacotot, Adrien; Marchand, Cyril; Gayral, Inès; Allenbach, Michel

doi: 10.1007/s13157-021-01461-2pmid: N/A

Carbon fractionation (Δ13C) is well documented for various plants functional types. Yet, specific studies on Δ13C on mangroves are particularly rare although they have a key role in coastal carbon (C) cycling. In this study, we investigated the 13C exchanges between leaves and the atmosphere and between the main plant’s organs in two common mangroves species, Avicennia marina and Rhizophora stylosa subjected to two different CO2 concentrations. Two-years-old saplings were grown in mesocosms during one year under 400 ppm and 800 ppm of CO2. At the end of the experiment, the isotopic value of the night-respired CO2 was measured on six individuals for each species and CO2 treatment. Then, 60 saplings were harvested to measure the organs δ13C values, and, finally, carbon fractionation (Δ13C) during photosynthesis, post-photosynthesis and apparent Δ13C during night respiration were calculated. Results indicated that elevated CO2 reduced Δ13C during photosynthesis by 13% and during night respiration by 20%. Alongside, within-plant Δ13C was twice higher in the saplings grown under elevated CO2 concentrations. These results showed that ongoing and future increases in atmospheric CO2 concentrations have the potential to modify the δ13C values of mangrove trees. These results could have important implications in Blue Carbon sciences, and particularly in the comprehension of future carbon cycling in coastal wetlands, mangroves being an essential link in terrestrial and marine food webs along tropical and subtropical coastlines.