Boosting large-scale river connectivity restoration by planning for the presence of unrecorded barriers

Conservation decisions are invariably made with incomplete data on species’ distributions, habitats, and threats, but frameworks for allocating conservation investments rarely account for missing data. We examined how explicit consideration of missing data can boost return on investment in ecosystem restoration, focusing on the challenge of restoring aquatic ecosystem connectivity by removing dams and road crossings from rivers. A novel way of integrating the presence of unmapped barriers into a barrier optimization model was developed and applied to the U.S. state of Maine to maximize expected habitat gain for migratory fish. Failing to account for unmapped barriers during prioritization led to nearly 50% lower habitat gain than was anticipated using a conventional barrier optimization approach. Explicitly acknowledging that data are incomplete during project selection, however, boosted expected habitat gains by 20–273% on average, depending on the true number of unmapped barriers. Importantly, these gains occurred without additional data. Simply acknowledging that some barriers were unmapped, regardless of their precise number and location, improved conservation outcomes. Given incomplete data on ecosystems worldwide, our results demonstrate the value of accounting for data shortcomings during project selection.     

Changes in the Distribution of Broadleaf Tree Species in the Central Part of the Southern Urals since the 1970s

Russian Journal of Ecology - Changes in the distribution of broadleaf tree species—Tilia cordata Mill., Quercus robur L., Acer platanoides L., and Ulmus glabra Huds.—in the central part...     

Correction to: Impact of precipitation disparity on groundwater fluctuation in a semi-arid region (Vellore district) of southern India using geospatial techniques

Environmental Science and Pollution Research - A Correction to this paper has been published: https://doi.org/10.1007/s11356-021-13406-7     

Dyes removal from water using polymeric nanocomposites: a review

Environmental Chemistry Letters - Most dyes are pollutants that should be removed from waters due to their mutagenic and carcinogenic properties, requiring advanced adsorption methods. Here, we...     

Carbon Emission from the Surface of Coarse Woody Debris in Korean Pine Forests of Southern Primorye

Carbon dioxide fluxes from the surface of coarse woody debris (CWD) have been measured in Korean pine forests of the southern Sikhote-Alin mountain range. The seasonal dynamics of oxidative conversion of CWD carbon have been evaluated, and average values of the CO₂ emission rate have been determined for CWD fragments of three tree species at different stages of decomposition. The degree of decomposition is an important factor of spatial variation in CO₂ emission rate, and temporal variation in this parameter is adequately described by an exponential function of both CWD temperature and air temperature (R² = 0.65–0.75).     

Correction to: Keeping pace with forestry: Multi-scale conservation in a changing production forest matrix

Ambio - In the original published article, the sentence “Nevertheless, semi-natural forest remnants continue to be harvested and fragmented (Svensson et al. 2018; Jonsson et al. 2019), and...     

The tox is in the detail: technical fundamentals for designing,performing, and interpreting experiments on toxicity of microplastics and associated substances

Over the last 10 years, there has been a plethora of experimental studies estimating the potential of microplastic particles (MPs) to exert toxic effects in the environment, many specifically focusing on their postulated capacity to enhance the transfer of environmental pollutants into organisms after ingestion. Obviously, there is little to no consensus on appropriate experimental design, which is mainly owing to the novelty, the interdisciplinarity of the subject, and the complexity of parameters involved. This results in fundamental discrepancies regarding the materials applied, the approach for spiking MPs with pollutants, and the exact exposure scenario. Aiming for a non-chemist audience and providing illustrative, representative, and comparative examples, this review first outlines the theoretical essentials of processes involved in sorption. Also, it discusses the implications for designing experimental approaches using MPs and interpreting the results obtained under consideration of their relevance for environmental conditions. It may help to improve the interpretation of studies on MP toxicity already published, while also calling experimenters’ attention to various aspects important to consider when designing and performing environmentally relevant experiments with MPs.

     

Hunting Selectivity and Its Influence on the Structure of Sable Populations in the Cis-Ural Region

The structure of commercial sable samples from the Cis-Ural region was studied taking into account hunting method (shooting or trapping). The proportion of adult animals was found to be significantly lower in samples taken during the first half of the hunting season, compared to the second half, indicating predominant harvesting of young animals. To estimate the degree of hunting selectivity (I), the ratios of demographic groups among shot and trapped animals were calculated. The results confirmed the fact of selective hunting for underyearlings both by shooting (I = 1.49–1.60 for the Cis-Ural region and I = 2.46–3.37 for the Western Sayan Mountains) and by trapping (I = 2.80–4.37), especially during the first half of winter. Samples taken during the second half of the season were characterized by prevalence of adult animals making up the reproductive core of the population (I = 1.43–2.07). It is considered that the process of reproduction in Cis-Ural sable populations in the 1960s to 1980s was stimulated by intensive commercial hunting. To maintain reproduction of sable populations at a safe level, it is necessary to reduce the period of hunting in the first quarter of the year. It is proposed to use the phenomenon of hunting selectivity for managing sable populations, regulating their exploitation, and improving the economic productivity of habitats. Commercial hunting in terms of its impact on the population can act as a factor of conscious or unconscious artificial selection.     

Water management and aquatic ecosystem services of a tropical reservoir (Itaparica,São Francisco,Brazil)

Reservoirs have a wide variety of uses that have led to frequent conflicts over ecological conservation and contamination, especially as land management has intensified. Oligotrophication must be implemented in numerous tropical reservoirs that experience advanced eutrophication to maintain aquatic ecosystem functions. To quantify impacts on ecosystem functions and to develop an adaptive management policy, multiple studies have been conducted on the Itaparica Reservoir, São Francisco River, in the semi-arid north-eastern region of Brazil. Here, we add to that existing body of knowledge through investigating how nutrient accumulation is affected by water exchange between the main river flow and Icó-Mandantes Bay. Operational water-level fluctuations in the reservoir create large desiccated littoral areas that release high amounts of nutrients when they are rewetted. In particular, water-level variation promotes proliferation of Egeria densa, a noxious weed, thus elevating trophic levels of the Itaparica Reservoir and Icó-Mandantes Bay. Analysis with a P efficiency model determined 25 μg P L^?1 to be the critical concentration and further indicated that the critical load in both bodies of water have been exceeded. Moreover, intensive fish aquaculture using net cages has led to further overtaxing of the reservoir. We conclude that an effective ecological reservoir management policy must involve oligotrophication, harvesting of noxious water weeds for use as soil amendment in agriculture or biogas production, “blue” aquaculture, and limiting hydroelectric power production based on current water availability.     

Partial characterization of the exopolysaccharide from Oscillatoria trichoides Szafer and the role of released polysaccharide in sequestration of Cr6+

The structural investigation and the chromium adsorptive potential of an exopolysaccharide (EPS) released during the growth of an indigenous cyanobacterium, Oscillatoria trichoides Szafer, were investigated in a laboratory‐scale study. The results showed that, of the total EPS produced, 410.53 milligrams/gram (mg g^?1) were released polysaccharides (RPS) and 11.36 mg g^?1 were capsular polysaccharides (CPS). The sorption of hexavalent chromium (Cr⁶⁺) by the RPS achieved a maximum amount of metal removal (q_max) value of 76.92 mg g^?1 of polysaccharide dry weight. The highest coefficient of determination (0.9742) for the Langmuir adsorption model indicates best fitness of the model in explaining the sorption as a unilayer process. Equilibrium studies indicated that 30 to 40 milligrams per liter initial chromium concentration and a pH of 2 were optimal for biosorption of chromium by the RPS. Scanning electron microscopy with energy‐dispersive X‐ray spectroscopy analysis of Cr⁶⁺‐treated RPS showed the presence of 3.76% bound chromium. Compositional analysis of the EPS showed the presence of carbohydrates, proteins, pyruvic acid, and hexosamines. High‐performance liquid chromatography analysis demonstrated the presence of hexoses, as neutral sugars and glucuronic acid as an acidic sugar. The presence of carboxylic groups was also detected by infrared spectroscopy. The presence of these chemical constituents may serve as binding sites for the metal ions; therefore, the RPS of this species appears to be a promising biosorbent for Cr⁶⁺.