Understanding runoff dynamics is vital for effective water management in climate-affected areas. This study focuses on the Dayekou basin in China’s Qilian Mountains, known for their high climate variability. Using 25 years of data (1994–2018) on river runoff, precipitation, and temperature, statistical methods were applied to explore the annual variations and climate change impacts on these parameters. Results reveal a significant variability in the river runoff (132.27 to 225.03 mm), precipitation (340.19 to 433.29 mm), and average temperature (1.38 to 2.08 °C) over the period. Decadal rising rates average 17 mm for runoff, 17 mm for precipitation, and 0.25 °C for temperature, with the peak precipitation and runoff occurring in 1998–2000, 2008, and 2016. The annual runoff distribution also exhibited a unimodal pattern, peaking at 39.68 mm in July. The cumulative runoff during low periods constituted only 13.84% of the annual total, concentrated in the second half of the year, particularly during the June-October flood season. The correlation analysis underscored a strong relationship between river runoff and precipitation (correlation coefficient > 0.80), while the temperature correlation was weaker (correlation coefficient < 0.80). This 25-year analysis provides valuable insights into runoff variation, elucidating the interconnected effects of temperature and precipitation in the Dayekou basin, with substantial implications for sustainable development amid climate challenges.

Invasive apple snails adversely impact the ecological function of non-native habitats, resulting in eutrophication as well as reduced biodiversity, which diminishes ecosystem goods and services, thereby [negatively] impacting human well-being. The onus here is to define the diet of an invasive apple snail (Pomacea canaliculata) in native (Maldonado, Uruguay) versus non-native habitats (Hangzhou, China, and Oahu, HI, USA). Diets for apple snails, in five sites, within both native and non-native habitats were defined via SIAR (Stable Isotope Analysis in R) with δ¹³C and δ¹⁵N stable isotope data collected therein. SIAR models indicate P. canaliculata shift diet from generalist (where myriad plant species comprise relatively small proportions of overall diet) to a specialist diet (where plants species constitute much larger proportions of said diet). What may be more telling is that in (anthropogenically disturbed) portions of the native habitat, and progressively more so in non-native habitats, invasive apple snail diets are increasingly composed of aquatic plants. The inherent and pronounced dietary differences amongst pristine and anthropogenically disturbed native habitats, as well as non-native habitats, provide a mechanism that may elucidate the variable ecological impacts of invasive apple snails within native and non-native habitats.

Invasive apple snails negatively impact non-native habitats and also human well-being. Here the trophic position of Pomacea canaliculata in native habitats (Maldonado, Uruguay) and non-native habitats (Hangzhou, China and Hawaii, USA) are compared to explain their differential impacts therein. Detritus samples and tissue samples from apple snails were collected in all sites. Apple snail trophic levels were calculated as the difference between the mean δ¹⁵N values of detritus samples and corresponding apple snail tissue samples, divided by the mean δ¹⁵N fractionation for nitrogen per trophic level in freshwater habitats. The mean δ¹⁵N values of detritus in sites served as a baseline (i.e.: zero trophic level), allowing for direct comparisons. Linear regression analysis established correlation between species evenness and apple snail trophic level (R² = 0.8602); in line with a Pearson's product-moment correlation value (-0.83) and 95% Confidence Interval (-0.87, -0.77). Normal quartile plots indicated two normally distributed subsets of apple snail trophic level data: (1) a biodiverse subset containing the Uruguayan and Chinese Lake Sites and (2) the homogenized Hawaiian and Chinese Creek Sites. A precipice value for species evenness, between (3.7) and (2.4), once descended to, or beneath, separates, statistically distinct, normal distributions of invasive apple snail trophic level data from diverse versus homogenized habitats. This value is akin to a fence separating biodiversity from homogenization, or habitats exhibiting biotic resistance from others with open niche space. This plausible mechanism explains invasive apple snails’ variable ecological impacts in native versus non-native habitats, and may predict the latters’ susceptibility to adverse impacts.

Invasive apple snails negatively impact non-native habitats and human well-being. Here, the trophic position of Pomacea canaliculata in native habitats (Maldonado, Uruguay) and non-native habitats (Hangzhou, China and Hawaii, USA) are compared. Detritus samples and tissue samples from apple snails were collected in all sites. Trophic levels were calculated as the difference between the mean δ¹⁵N values of detritus samples and corresponding apple snail tissue samples, divided by the mean δ¹⁵N fractionation for nitrogen per trophic level in freshwater habitats. The mean δ¹⁵N values of detritus in sites served as a baseline (i.e., zero trophic level), allowing direct comparisons. Linear regression analysis established a correlation between species evenness and apple snail trophic level (R² = 0.8602) in line with a Pearson’s product-moment correlation value (−0.83) and 95% confidence interval (−0.87, −0.77). Normal quartile plots indicated two normally distributed subsets of apple snail trophic-level data: (1) a biodiverse subset containing the Uruguayan and Chinese lake sites and (2) the homogenized Hawaiian and Chinese creek sites. A precipice value for species evenness (separating biodiversity from homogenization), between (3.7) and (2.4), once descended to or surpassed separates statistically distinct, normal distributions of invasive apple snail trophic-level data from diverse versus homogenized habitats.