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Urbanization and agricultural activities are increasingly threatening karstic systems and the water resources they provide, which are crucial for the livelihood of rural communities. Over the past decade, the Río Grande de Comitán-Lagos de Montebello (RGC-LM) watershed in Chiapas, Mexico, has experienced significant deterioration in water quality. The objective of this study was to analyze the water quality dynamics within the RGC-LM watershed and their potential interaction with land use change. We conducted assessments of the physicochemical and microbiological parameters across the lotic and lentic systems within the watershed over eight monitoring campaigns (from 2013 to 2020). Cluster Analysis (CA) and Principal Component Analysis (PCA) statistical approaches were performed to identify the main drivers of surface water quality variability. This approach aims to enhance water quality assessments within environmental management strategies, with the goal of promoting sustainable land-use practices aimed at protecting and improving water resources within the watershed. Our findings indicate that there is a substantial difference between the upper and lower watershed water quality. The good water quality conditions observed in the higher altitude lakes (mountain lakes) can be attributed to favorable topographical features, specific land use patterns, and effective conservation measures. In contrast, the lotic system in the middle watershed and the lentic water bodies located at lower altitudes (plain lakes) exhibit signs of water quality degradation due to inefficient wastewater treatment and agricultural runoff. This study highlights the importance of implementing adequate environmental management strategies to address these water quality challenges effectively. Given the pressing issue of water quality degradation in karstic environments, we emphasize on the need for increased monitoring frequency of both physicochemical and microbiological parameters to capture seasonal variations and to further understand the vulnerability of water resources in karstic environments. Future assessment of nutrient concentrations, pesticide levels, and blue-green algae populations will also be crucial for evaluating the trophic state at a watershed scale.

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Background: The efficacy of transcranial direct current stimulation (tDCS) has been studied extensively. The cathodic (c‐tDCS), anodic (a‐tDCS), and bihemispheric stimulation have demonstrated efficacy in the management of the paretic upper extremity (UE) after stroke, but it has not been determined which stimulation polarity has, so far, shown the best results. Objective: To evaluate the available evidence to determine which tDCS polarity has the best results in improving UE motor function after stroke. Methods: PubMed, PEDro, Web of Science, EMBASE, and SCOPUS databases were searched. Different Medical Subject Headings (MeSH) terms were combined for the search strategy, to cover all studies that performed a comparison between different tDCS configurations focused on UE motor rehabilitation in people with lived experience of stroke. Results: Fifteen studies remained for qualitative analysis and 12 for quantitative analysis. Non‐significant differences with a 95% confidence interval (CI) were obtained for c‐tDCS versus a‐tDCS (g = 0.10, 95% CI = −0.13; 0.33, p =.39, N = 292), for a‐tDCS versus bihemispheric (g = 0.02, 95% CI = −0.46; 0.42, p =.93, N = 81), and for c‐tDCS versus bihemispheric (g = 0.09, 95% CI = −0.84;.66, p =.73, N = 100). No significant differences between the subgroups of the meta‐analysis were found. Conclusions: The results of the present meta‐analysis showed no evidence that a stimulation polarity is superior to the others in the rehabilitation of UE motor function after stroke. A non‐significant improvement trend was observed toward c‐tDCS compared to a‐tDCS. [ABSTRACT FROM AUTHOR]

Copyright of Ecologia Austral is the property of Asociacion Argentina de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Species interactions are critical for maintaining community structure and dynamics, but the effects of invasive species on multitrophic networks remain poorly understood. We leveraged an ongoing invasion scenario in Patagonia, Argentina, to explore how non-native ungulates affect multitrophic networks. Ungulates disrupt a hummingbird–mistletoe–marsupial keystone interaction, which alters community composition. We sampled pollination and seed dispersal interactions in intact and invaded sites. We constructed pollination and seed dispersal networks for each site, which we connected via shared plants. We calculated pollination-seed dispersal connectivity, identified clusters of highly connected species, and quantified species' roles in connecting species clusters. To link structural variation to stability, we quantified network tolerance to single random species removal (disturbance propagation) and sequential species removal (robustness) using a stochastic coextinction model. Ungulates reduced the connectivity between pollination and seed dispersal and produced fewer clusters with a skewed size distribution. Moreover, species shifted their structural role, fragmenting the network by reducing the 'bridges' among species clusters. These structural changes altered the dynamics of cascading effects, increasing disturbance propagation and reducing network robustness. Our results highlight invasive species' role in altering community structure and subsequent stability in multitrophic communities. [ABSTRACT FROM AUTHOR]