Sources and pathways of spring flow and climate change effects in the Dungju Ri & Yude Ri catchments, Bhutan Himalaya.

Springs and streams are vital water sources for supporting the livelihood of Himalayan residents. Escalating climate change, population growth, and economic development strain the region's freshwater resources. A national survey reveals declining spring and stream flows in Bhutan, necessitating an improved understanding of their generation. Monthly grab water samples were collected during April 2022-January 2023 from main streams, springs and other source waters at various elevations at Yude Ri and Dungju Ri catchments, Bhutan Himalayas. Samples were analyzed for pH, specific conductance, and major ions and end-member mixing analysis in combination with diagnostic tools of mixing models was used to determine sources, relative contributions, and recharge dynamics of spring flows. The results indicated that direct precipitation dominated spring flows (0.59 ± 0.21), followed by shallow groundwater (0.31 ± 0.18), and soil subsurface water (0.10 ± 0.15). The contributions of spring flow components followed an elevation gradient, with higher and lower fractions, respectively, of direct precipitation and shallow groundwater at higher elevations, e.g., 0.90 ± 0.1 to 0.13 ± 0.08 for direct precipitation and 0.03 ± 0.03 to 0.37 ± 0.19 for shallow groundwater from 3266 m to 1558 m. Spring flows primarily relied on precipitation (∼70 % from both direct precipitation and soil water), making them very sensitive to changes in precipitation. Significant contributions of shallow groundwater also indicated the vulnerability of spring flows to decreased snowfall relative to rainfall and the earlier onset of snowmelt, particularly for those located in the snow-rain transition zone (∼2500 m). Our results suggest high vulnerability of spring flows to the climate change in the Himalayas.

Lichens as spatially transferable bioindicators for monitoring nitrogen pollution.

Excess nitrogen is a pollutant and global problem that harms ecosystems and can severely affect human health. Pollutant nitrogen is becoming more widespread and intensifying in the tropics. There is thus a requirement to develop nitrogen biomonitoring for spatial mapping and trend analysis of tropical biodiversity and ecosystems. In temperate and boreal zones, multiple bioindicators for nitrogen pollution have been developed, with lichen epiphytes among the most sensitive and widely applied. However, the state of our current knowledge on bioindicators is geographically biased, with extensive research effort focused on bioindicators in the temperate and boreal zones. The development of lichen bioindicators in the tropics is further weakened by incomplete taxonomic and ecological knowledge. In this study we performed a literature review and meta-analysis, attempting to identify characteristics of lichens that offer transferability of bioindication into tropical regions. This transferability must overcome the different species pools between source information - drawing on extensive research effort in the temperate and boreal zone - and tropical ecosystems. Focussing on ammonia concentration as the nitrogen pollutant, we identify a set of morphological traits and taxonomic relationships that cause lichen epiphytes to be more sensitive, or more resistant to this excess nitrogen. We perform an independent test of our bioindicator scheme and offer recommendations for its application and future research in the tropics.

Knowledge and attitude on sexually transmitted infections and contraceptive use among university students in Bhutan.

OBJECTIVES: The unmet needs of contraception can lead to unintended pregnancy and transmission of sexually transmitted infections (STI). Therefore, this study aimed to evaluate the contraception use, knowledge, and attitude on STI among students under Royan University of Bhutan (RUB). METHODS: This was a cross-sectional study using an online questionnaire. The questionnaire was developed in Google forms and the link was shared through the college WeChat groups. The questionnaire consisted of four parts on socio-demographic, sexual behaviour and contraceptive use, knowledge, and attitude on STIs. All the students under RUB were invited to participate voluntarily in this study. The socio-demography was presented in frequency and proportion. RESULT: A total of 1,283 students participated in this survey and 55.0% (701) were females. Of this, 29.4% (377) were sexually active and 94.4% reported using modern contraception. Commonly used contraceptives were: condoms (83.8%, 316) and emergency contraceptives (20.6%, 78), respectively. The mean knowledge and attitude scores on STI were 9.94 (range 2-20) and 12 (range 2-14), respectively. Good knowledge and attitude on STI were reported in 53.2% (683) and 70.1% (899) of participants. CONCLUSION: Students reported average knowledge and a good attitude towards STI. Contraceptive use among university students was low. There is a need to strengthen health education on STIs in schools and universities. All forms of contraceptives especially condoms should be made easily available to sexually active people.