Ecologies, Volume 3, Issue 2 (June 2022) – 14 articles

Amphibian populations are threatened globally by stressors, including diminishing availability of suitable wetland breeding sites, altered hydroregimes driven by changing weather patterns, and exposure to contaminants. Ecological risk assessment should encompass spatial and temporal scales that capture influential ecological processes and demographic responses. Following the PopGUIDE framework of population model development for risk assessment, we used matrix population models, in conjunction with existing hydroregime predictions, under a climate change scenario to evaluate the effects of environmental stochasticity and aquatic pesticide exposure on amphibians that are dependent on ephemeral wetlands. Using southern toads (Anaxyrus terrestris) as an example, we simulated population dynamics with breeding success dependent on hydroregime suitability. Years were defined as optimal, marginal, or insufficient for successful toad recruitment, based on the duration of their potential breeding season and rate of larval development to metamorphosis. We simulated both probabilistic and chronologically specific population projections, including variable annual fecundity, based on hydroregime suitability and reduced larval survival from carbaryl exposure. In our simulations, populations were more negatively impacted by prolonged drought, and consequently multiple sequential years of reproductive failure, than by aquatic pesticide exposure. These results highlight the necessity of reliable climate projections to accurately represent the effects of altered hydroregimes on amphibian populations. Risk assessment approaches could be improved with flexible modifications that allow inclusion of various extrinsic stressors and identification of demographic and ecological vulnerabilities when precise data are lacking. Full article

In the quest of finding local strains of marine ciliates that can be easily cultured under a broad range of salinity and fed with microalgae, Fabrea salina Henneguy, 1890 and Condylostoma sp. Bory de St. Vincent, 1826 were cultured for 22 days in small volumes at a temperature of 16–18 °C and fed with flagellated microalgae. F. salina presented a clear preference for the salinity of 40 ppt and Condylostoma. sp. for 20 ppt. Rhodomonas salina Hill and Wetherbee, 1989 were the most efficient feeds, resulting in 30 ind./mL in F. salina and 73 ind./mL in Condylostoma. Dunaliella salina Teodoresco, 1905 and Nephroselmis sp. F. Stein, 1878 also resulted in considerable ciliate densities while Isochrysis galbana Parke, 1949 came last with the highest density in Condylostoma. The strain of Tetraselmis sp. F. Stein, 1878 (var. red pappas) which is transformed in immobilized palmelloid cells and the dinoflagellate Amphidinium carterae Hulburt, 1957, which is suspected of toxin production, were inappropriate for both ciliates. These ciliates can be easily cultured and can serve as useful organisms in bioassays and probably as live food in marine fish hatcheries. Full article

Micro-pollutants especially estrogens, progesterone, androgens, glucocorticoids, and growth hormones, are biological and chemical impurities that find their way into natural aquatic environments in trace quantities (ng/L), and possess a significant disturbance by impacting human and aquatic life. Due to the significant progress in in the analysis and detection techniques, these trace elements have been observed and quantified in several studies. However, as a result of limited methods and management technology, the adverse effects by these micro-pollutants in surface and coastal water is largely unknown. For this study, the compounds of estrogens, progesterone, androgens, glucocorticoids, and growth hormones have been selected according to their high frequent detection value in environmental waters. The concentration of the selected steroid and hormones ranges from 0.1–196 ng/L (estrogens), less than 0.1 to 439 ng/L (progesterone), 0.06–86 ± 2 (androgens), less than 0.1 to 433 ng/L (glucocorticoids), and 26.6 ng/g to 100 ng/L (growth hormones), and their percentage of removal efficiency varies from less than 10% to 99%, as the measurement of compounds concentration was found to be very low. Here, we report that future studies are necessary to detect the entry routes of these compounds into the environmental water, as well as to explore the technological approaches which are able to resolve this issue permanently. Full article

Mechanistic models are invaluable in ecological risk assessment (ERA) because they facilitate extrapolation of organism-level effects to population-level effects while accounting for species life history, ecology, and vulnerability. In this work, we developed a model framework to compare the potential effects of the fungicide chlorothalonil across four listed species of cyprinid fish and explore species-specific traits of importance at the population level. The model is an agent-based model based on the dynamic energy budget theory. Toxicokinetic-toxicodynamic sub-models were used for representing direct effects, whereas indirect effects were described by decreasing food availability. Exposure profiles were constructed based on hydroxychlorothalonil, given the relatively short half-life of parent chlorothalonil. Different exposure magnification factors were required to achieve a comparable population decrease across species. In particular, those species producing fewer eggs and with shorter lifespans appeared to be more vulnerable. Moreover, sequentially adding effect sub-models resulted in different outcomes depending on the interplay of life-history traits and density-dependent compensation effects. We conclude by stressing the importance of using models in ERA to account for species-specific characteristics and ecology, especially when dealing with listed species and in accordance with the necessity of reducing animal testing. Full article

Researchers have studied the impact of various anthropogenic activities on litter decomposition rates because of their large impact on the future carbon budget and climate change. However, any assessment of the global-scale impact of anthropogenic activity on litter decomposition requires standardized methods that can exclude the variability of litter chemistry. The Tea Bag Index (TBI) is widely used as a standardized method to obtain both the decomposition constant k of early-stage litter decomposition and the stabilization factor S. Recently, a tea bag manufacturer changed the materials and size of the tea bag mesh from a 0.25 mm woven mesh to a nonuniform, nonwoven mesh. To test whether these changes in mesh materials have any effect on the TBI approach, an incubation study was performed. Obtaining time series decomposition data for both green and rooibos teas, two essential assumptions of the TBI approach were examined: (i) that most of the unstabilized hydrolyzable fraction of green tea is decomposed within 90 days (unless the environment is unfavorable for decomposition) and (ii) the S of green tea is equal to that of rooibos tea. The results did not show a clear breakdown of the first assumption of the TBI approach due to the changes in mesh materials, and they did not support the second assumption. The S of rooibos tea determined by fitting an asymptote model to the time series data was significantly larger than the TBI-based S. In conclusion, the TBI may be undeterminable using nonwoven tea bags. Full article

The development of new insecticides for vector control that are toxicologically safe and eco-friendly (such as those obtained from industrial by-products) is an important public health concern. Previous research has shown that the obtained tCNSL (technical cashew nutshell liquid) + NatCNSLS (sodium tCNSL sulfonate mixture) emulsion displayed both surfactant properties and larvicidal activity (LC50-24 h 110.6 mg/L). Thus, the emulsion is considered a promising alternative product for the control of Aedes aegypti. The goal of this study was an ecotoxicological evaluation of the tCNSL + NatCNSLS mixture emulsion and its components. In addition, we compared the toxicity of the tCNSL + NatCNSLS mixture emulsion with toxicity data from larvicide currently recommended by the World Health Organization (WHO). Ecotoxicological tests were performed to assess acute toxicity, phytotoxicity, cytotoxicity, genotoxicity, and mutagenicity using Daphnia similis, Pseudokirchneriella subcapitata, Oreochromis niloticus, Allium cepa, and Salmonella enterica serovar Typhimurium. Regarding acute toxicity, D. similis was the most sensitive test organism for the three evaluated products, followed by P. subcapitata and O. niloticus. The highest acute toxicity product was tCNSL. The tCNSL + NatCNSLS mixture emulsion did not show cytotoxic, genotoxic, or mutagenic effects, and showed low acute toxicity to D. similis. In addition, the tCNSL + NatCNSLS mixture emulsion presented a lower or similar toxicological classification to the larvicides recommended by the WHO. Therefore, ecotoxicological tests suggest that the tCNSL + NatCNSLS mixture emulsion can be considered a larvicide environmentally safe way to control Ae. aegypti. Full article

Under standard guidance for conducting Ecological Risk Assessments (ERAs), the risks of chemical exposure to diverse organisms are most often based on deterministic point estimates evaluated against safety-factor-based levels of concern (LOCs). While the science and guidance for mechanistic effect models (e.g., demographic, population, and agent-based) have long been demonstrated to provide more ecologically relevant effect endpoints upon which risk can be evaluated, their application in ERAs has been limited, particularly in the US. This special issue highlights the state of the science in effect modeling for ERAs through demonstrated application of the recently published Population modeling Guidance, Use, Interpretation, and Development for ERA (Pop-GUIDE). We introduce this issue with a perspective on why it is critical to move past the current application of deterministic endpoints and LOCs. We demonstrate how the current, widely used approaches contain extensive uncertainty that could be reduced considerably by applying models that account for species life histories and other important endogenous and exogenous factors critical to species sustainability. We emphasize that it is long past time to incorporate better, more robust, and ecologically relevant effect models into ERAs, particularly for chronic risk determination. The papers in this special issue demonstrate how mechanistic models that follow Pop-GUIDE better inform ERAs compared to the current standard practice. Full article

Recent research has provided valuable momentum for the development and use of population models for ecological risk assessment (ERA). In general, ERA proceeds along a tiered strategy, with conservative assumptions deployed at lower tiers that are relaxed at higher tiers with ever more realistic models. As the tier increases, so do the levels of time and effort required by the assessor. When faced with many stressors, species, and habitats, risk assessors need to find efficiencies. Conservative lower-tier approaches are well established, but higher-tier models often prioritize accuracy, and conservative approaches are relatively unexplored at higher tiers. A principle of efficiency for ecological modeling for population-level ecological risk assessment is articulated and evaluated against a conceptual model and an existing set of avian models for chemical risk assessment. Here, four published avian models are reviewed in increasing order of realism (risk quotient → Markov chain nest productivity model → endogenous lifecycle model → spatially explicit population model). Models are compared in a pairwise fashion according to increasing realism and evaluated as to whether conservatism increases or decreases with each step. The principle of efficiency is shown to be a challenging ideal, though some cause for optimism is identified. Strategies are suggested for studying efficiency in tiered ecological model deployment. Full article

Plants and their derivatives, such as fruits, can be inhabited by different bacteria. However, this microbiota is still poorly studied. Among the wide variety of metabolites that bacteria produce, biosurfactants have been identified as potential molecules in the development of bioprocesses for various industrial sectors. In this work, we analyzed and compared the microbiota of fruit residues (mango and orange), in order to compare two possible sources of bioprospecting. For this, a bioinformatics approach was used to perform the taxonomic analysis and the prediction of the functional profile of the microbiota present in the samples. The results showed that the microbiota present in both fruit residues have the potential in biotechnological applications to produce biosurfactants, as these microbiota have genes related to the biosynthesis of these compounds. The common core of the microbiota present in the samples—Stenotrophomonas, Klebsiella, Serratia and Citrobacter—proved, according to the literature, to be composed of biosurfactant producers, showing the biosurfactant potential of the bacteria isolated from orange and mango residues. Full article

A comparison of two closely located reservoirs on the Southern Bug River and its tributary in the southern region of Ukraine is carried out. One of them (Tashlyk reservoir on a small river, tributary of the Southern Bug River) is a cooling reservoir (pond) for the nuclear power plant, the other (Alexandrovskoye reservoir, on the Southern Bug River) is used for agricultural purposes, for the production of electricity at a hydroelectric power plant, and as a lower reservoir for a pumped storage power plant. Comparison of the main indicators of phytoplankton in the reservoirs was carried out together with its spatial distribution. It was found that the distribution of coenotic groups of plankton in the cooling reservoir corresponds to thermal conditions. In the Alexandrovskoye reservoir, separate communities of plankton are formed along its length. The description of indicator species of algae in two reservoirs is given. The important role of the catchment basin was demonstrated with statistical maps. It was shown that a significant increase in temperature in the cooling pond did not lead to the depletion of phytoplankton. Full article

Invasive crayfish are among the major threats to freshwater ecosystems, with the signal crayfish, Pacifastacus leniusculus, being one of the most successful crayfish invaders in Europe. Approaches to invasive crayfish control range from manual and physical to biological and biocidal control methods. However, all of these approaches have their drawbacks and have limited efficacy. Among traditional approaches with minimal impacts on environment and non-target species, manual control via trapping is the most frequently applied. More innovative approaches comprise, among others, usage of sterile male release technique, whose efficacy in the field is yet to be fully tested, especially how it combines with more traditional approaches. A good alternative to costly and logistically challenging field comparisons of these approaches and their combinations is population modeling. Population models can integrate all relevant species-specific biological and ecological information and can be applied to identify management scenarios of highest impact on invasive crayfish abundances. In this study, we developed a conceptual population model of the invasive P. leniusculus following the Pop-GUIDE framework. In addition, we expanded on the framework to increase its applicability to other fields beyond environmental risk assessment. Finally, we discuss potential application of the model and its future use as a management tool. Full article

Ivorian classified forests have been highly anthropized by cocoa farming. In an attempt to provide guidance to the government on approaches to the restoration of the forest while respecting the aspirations of local populations, permanent plots were set up in the classified forest of Haut-Sassandra, and were monitored and measured for 3 years. This study was intended to analyze the evolution of the vegetation of permanent plots in the classified forest of Haut-Sassandra from 2018 to 2021. The results show that the vegetation evolves with the cessation of some agricultural activities. These plantations are colonized by pioneer species during the first three years of the abandonment of agricultural activities. Mortality rates increased by 477.59% and recruitment rates were reduced by 61.87% in regularly maintained plantations compared to their condition three years ago. However, the plantations with no agricultural activities and those which were not maintained but harvested had the highest recruitment rates of pioneer and heliophilous individuals. In sum, tree species could recolonize the classified forest of Haut-Sassandra if clearing is prohibited in cocoa farms. However, the populations could continue to harvest the pods from the cocoa trees which are already established in the classified forest of Haut-Sassandra. Full article

The red-footed falcon (Falco vespertinus) is a species that is of great interest to conservation. Because of this, understanding the red-footed falcon’s flight behavior is important for the conservation of this species. In this context, by using accurate GPS data-loggers, in 2019 and 2020, we analyzed its flight activity at the two largest colonies in Italy, and we collected 5840 GPS points. At night, all of the surveyed individuals were active during all of the hourly intervals, and they were in flight for about 10% of the time (40% in the daytime). The nocturnal flight activity showed a dual pattern: frequent and long-distance flights before sunrise (22.22% of time in flight; maximum distance from nest > 3 km) and after sundown (32.14% of time in flight; maximum distance from nest > 12 km), and limited and short-distance flights late at night (10 p.m.–5 a.m.; <5% of time in flight; maximum distance from nest < 100 m). Our study suggests that an increase in alfalfa crops and fallow land (in place of maize and soy crops) in the surroundings (i.e., 50–100 m) of the nests would considerably help this species to avoid, or at least to minimize, nocturnal flight activity, with expected improvements in its reproductive success. Our results are a step forward in advancing the knowledge of this important red-footed falcon population, which has been largely unknown so far. We provide here the first evidence ever of the red-footed falcon’s regular nocturnal flight activity during the nestling period (June–July). Full article

Commiphora species are of high medicinal importance. They are distributed in Saudi Arabia, mainly in rocky habitats and regions under mountains, including the east of Tihama, forming a distinct element of Saudi flora. The present study focuses on the botanical characterization of five species of Commiphora, i.e., C. erythraea, C. gileadensis, C. kataf, C. myrrha, and C. quadricincta. The morphological characters for each species were recorded comparatively, and their taxonomic relationships were examined using gross morphology by generating a UPGMA dendrogram, which separated the Commiphora species into two distinct groups. A dichotomous key was generated to facilitate the identification process of the plant, even by naked eye, by obvious characteristics. Because of the similarities in anatomical structure of the stem and petiole of most studied species, only the quantitative variations are illustrated comparatively. Seed macro- and micro-morphological characteristics were recorded comparatively to be used in the identification of a species in the case of leaf absence. The phytochemical study included measurements of total phenolic and flavonoid contents. The phytochemical results were correlated with the ethno-botanic survey. The traditional uses for all species were recorded using the questionnaire and open interviews method for data collecting. The results revealed that the most common Commiphora species that are traditionally used are C. myrrha and C. gileadensis. The study recommends more research on Commiphora species using more advanced techniques and tries to increase public awareness on the importance of these plants. Full article