Spatial Heterogeneity in Prey Availability, Feeding Success, and Dietary Selectivity for the Threatened Longfin Smelt

Food availability is a key determinant of the nursery value of a given habitat for larval and juvenile fishes. Growth, survival, and recruitment success are often inter-correlated and influenced by prey availability and associated feeding success. This is likely true for the threatened population of Longfin Smelt (Spirinchus thaleichthys) in the San Francisco Estuary (SFE) which has collapsed in recent decades along with its preferred prey. In years with high precipitation and freshwater outflow, larval Longfin Smelt are found in shallow wetland habitats throughout the SFE, but variation in the availability of food and feeding success in these habitats remains unexplored. To examine spatial variation in the trophic value of different rearing habitats, we quantified variation in prey availability, feeding success, and prey selection for larval and juvenile Longfin Smelt captured in restored tidal marshes, sloughs, and open-water habitats in the northern and southern SFE. Prey abundance varied spatially, with densities approximately tenfold greater in southern sloughs and restored tidal ponds relative to northern and open-water habitats. Feeding success of larval Longfin Smelt was positively correlated with both fish length and prey density. Larval Longfin Smelt fed selectively on the copepod Eurytemora affinis, with larger individuals (> 25 mm total length) exhibiting an ontogenetic diet shift to larger mysid shrimps. Our results suggest that wetland habitats across the SFE vary greatly in their trophic value, with previously unexplored habitats exhibiting the highest densities of prey and the highest foraging success for larval Longfin Smelt.

Proximity to Riparian Wetlands Increases Mercury Burden in Fish in the Upper St. Lawrence River

Mercury deposited in the Upper St. Lawrence River watershed by atmospheric deposition accumulated in riparian wetlands and is at risk of remobilization due to water level fluctuations. To examine if riparian wetlands are a source of mercury to fish, 174 yellow perch (Perca flavescens) and 145 round gobies (Neogobius melanostomus) were collected in 2019 from eight wetland and seven non-wetland habitats throughout the Upper St. Lawrence River. Mercury levels were significantly (p < 0.01) higher in fish collected from wetlands than those collected from non-wetland habitats for both yellow perch and round goby. Perch had mercury concentrations of 74.5 ± 35.4 ng/g dry wt in wetlands compared to 59.9 ± 23.0 ng/g dry wt in non-wetlands. Goby had mercury concentrations of 55.4 ± 13.8 ng/g dry wt in wetlands and non-wetland concentrations of 41.0 ± 14.0 ng/g dry wt. Riparian wetlands are areas of elevated mercury methylation and mobilization in the Upper St. Lawrence River and consequences to predators should be considered from the perspective of both wildlife preservation as well as fish consumption advisories for public health concerns.

Phytodiversity in Relation to Some Environmental Factors Of Some Wetland Habitats

The present research work was carried out on phytodiversity in relation to some environmental factors of three ponds namely, Pond-1, Pond-2 and Pond-3 of Zanjira upazila at Shariatpur district, Bangladesh where a total of 13 parameters were measured for one year. Monthly average different parameters of three ponds varied : air temperature from 23.5-36.50˚ C, water temperature 21-30.50 ˚ C,pH 7.10-8.50, TDS 55-227 mg/l, EC 103-463 μS/cm, DO 2.90-19.94 mg/l, alkalinity 0.73-5.40 meq/l, SRP 7.11-229.84 μg/l, SRS0.84-13.34 mg/l, NO3-N0.02-0.96 mg/l, chla1. 18-31.97 μg/l, phaeopigment 0.26-5.46 μg/l and phytoplankton density 6.50-119.50×106 ind/l. The total number of 122 species of phytoplankton were recorded in the studied ponds. Phytoplankton density showed positive correlation with air temperature, water temperature, pH, TDS, EC, alkalinity and SRP for Pond-1. Phytoplankton density showed positive correlation with pH, TDS, EC, DO and alkalinity for Pond-2. On the other hand phytoplankton density of Pond-3 showed positive correlation with air temperature, water temperature, TDS, EC, alkalinity, SRP, SRS, NO3-N and chlorophyll-a. During the period of present investigation some aquatic plants were found to grow in those shallow margins of the studied three ponds. Results indicated that Pond-1 is in a position undergoing eutrophic status, Pond-2 and Pond-3 are in the oligotrophic status. If the anthropogenic disturbances are continued in these ponds, it is likely that in near future these ponds would turn to eutrophic. Bangladesh J. Bot. 50(4): 1087-1094, 2021 (December)

Water Management Balance as a Tool for Analysis of a River Basin with Conflicting Environmental and Navigational Water Demands: An Example of the Warta Mouth National Park, Poland

Allocating finite water resources between different water uses is always a challenging task. Searching for a solution which satisfies the water needs (requirements) of all water users without compromising the water requirements of river ecosystems calls for analyzing different water management options and their expected consequences. Water management balances are usually used for comparison of water resources with the needs of water users. When aquatic and water dependent ecosystems are considered in a similar manner as other users, searching for the optimum water resources allocation, without neglecting requirements of the natural environment, is possible. This paper describes basic modeling assumptions and methodological solutions, which allow for taking into account some tasks related to the protection of aquatic and water dependent ecosystems. The water balance model, developed for a catchment comprising the Warta Mouth National Park, was applied to find out whether supplying adequate amounts of water for conservation (or restoration) of wet meadows and wetland habitats in the area is possible, while still satisfying the demands of other water users.

Phylogenetic Diversity of Wetland Plants across China

Accelerating and severe wetland loss has made wetland restoration increasingly important. Current wetland restorations do not take into consideration the ecological adaptability of wetland plants at large scales, which likely affects their long-term restoration success. We explored the ecological adaptability, including plant life forms and phylogenetic diversity, of plants across 28 wetlands in China. We found that perennial herbs were more common than annual herbs, with the proportion of perennial herbs accounting for 40–50%, 45–65%, 45–70%, 50–60%, and 60–80% of species in coastal wetlands, human-made wetlands, lake wetlands, river wetlands, and marsh wetlands, respectively. A ranking of phylogenetic diversity indices (PDIs) showed an order of marsh < river < coastal < lake < human-made, meaning that human-made wetlands had the highest phylogenetic diversity and marsh wetlands had the lowest phylogenetic diversity. The nearest taxon index (NTI) was positive in 23 out of 28 wetlands, indicating that species were phylogenetically clustered in wetland habitats. Dominant species tended to be distantly related to non-dominant species, as were alien invasive species and native species. Our study indicated that annual herbs and perennial herbs were found in different proportions in different types of wetlands and that species were phylogenetically clustered in wetland habitats. To improve wetland restoration, we suggest screening for native annual herbs and perennial herbs in proportions that occur naturally and the consideration of the phylogenetic similarity to dominant native species.

Redescription of Sartoriana trilobata (Alcock, 1909) (Crustacea: Decapoda: Brachyura: Gecarcinucidae) from Assam, Northeast India, with notes on the morphology of male gonopods

Sartoriana trilobata is a species of freshwater crab which occurs exclusively in some areas of Northeast India. Being a riverine crab, it is occasionally found in beels or other riverine wetland habitats formed by monsoon floods in the Brahmaputra basin.The earlier descriptions of this species were mostly incomplete which lacked information on the morphology of the male gonopods.Therefore including the male gonopods, all the morphological features of Sartoriana trilobata are redescribed and illustrated. This species differs considerably from its only congener i.e., Sartoriana spinigera through suits of carapace, chelipeds, gonopods dissimilarities.

Toxic Meals for Seabirds and Seals: Monitoring Mercury in the San Francisco Bay

Mercury is a metal pollutant that travels thousands of miles through air and water. It flows along rivers to lakes, estuaries, and the sea, cycling between animals and their environments. Extensive mercury mining during the Gold Rush left lasting impacts on the San Francisco Bay Delta, one of California’s largest wetland habitats and home to thousands of species. Burning fossil fuels in cities like San Francisco also releases mercury, leading to its buildup in local food chains. Mercury accumulates from plankton to fish to top predators like sharks and seals, where it reaches potentially harmful levels. Mercury never fully breaks down and continues cycling in ecosystems, even reaching migratory animals living offshore in the Pacific Ocean. Scientists collect samples from wildlife to uncover clues about mercury sources and threats to human health. This article explains the mercury problem and why we track this invisible pollutant in the San Francisco Bay.

Lindernia crustacea (Malaysian false pimpernel).

L. crustacea is an herb including in the Global Compendium of Weeds where it is listed as environmental and agricultural weed (Randall, 2012). It has a wide distribution across tropical and subtropical regions of the world where it occurs in a wide range of wetland and some non-wetland habitats and is able to exploit anthropogenic habitats such as rice fields. Once established, this species has the potential to grow forming a mat up to 30 cm high. Currently, L. crustacea is listed as invasive in Hawaii, French Polynesia and Singapore (Wagner, 1999; Chong et al., 2009; Lansdown, 2011).