Future hydrological constraints of the Montseny brook newt (Calotriton arnoldi) under changing climate and vegetation cover

Thermal Tolerance and Preferred Temperature in the Critical Endangered Montseny Brook Newt (Calotriton arnoldi)

Climate change, driven by increased human greenhouse gas emissions since the beginning of the industrial revolution up to the present day, is considered one of the major threats to biodiversity in the twenty-first century. One of the most affected groups is the ectotherms due to their direct dependence on environmental temperatures. In recent years, several studies have analysed the effects of temperature and thermal tolerance on several species of ectotherms. However, there are species whose thermal tolerances are still unknown. Such is the case of the critically endangered species, the Montseny Brook Newt (Calotriton arnoldi), endemic to the Montseny massif in Spain and whose thermal biology is unknown. Its critical situation makes it essential to know its tolerance to cooling, warming and thermopreferendum in water environments where the newt lives. Three experimental procedures were conducted from the western and eastern subspecies of C. arnoldi, considering four classes separately (males, females, juveniles and larvae). The results obtained showed that the CTmax of the species exceeded 31 °C, with a significant difference between the two subspecies. We found that the species tolerates low temperatures (<1 °C) well because the genera Calotriton is adapted to live in cold waters with temperatures below 15 °C. Although the thermopreference of the species was expected to trend to cold temperatures, some individuals chose relatively high temperatures, obtaining a range of 11.7 °C to 21.6 °C. The results presented in this study are an advance in the knowledge of the thermal physiology of this species and support the importance of the temperature of the torrent on its survival. Knowing their thermal limits and their preferred temperature range will help to propose management measures that promote the conservation of streams and riparian forest cover to mitigate temperature increases due to climate change.

Habitat Management of the Endemic and Critical Endangered Montseny Brook Newt (Calotriton arnoldi)

Calotriton arnoldi is an endemic amphibian inhabiting Montseny Natural Park and Biosphere Reserve (PNRBM), listed as “critically endangered (CR)” by IUCN. At the end of 2016, the Life Tritó del Montseny (LIFETM) project (LIFE15 NAT/ES/000757) was launched. The aim of the project was to promote around fifty actions to ensure the conservation of C. arnoldi and its natural habitat, and this entailed five strategic lines: (1) Increasing the scientific and technical knowledge with regard to C. arnoldi’s conservation status and its habitat management. (2) Expanding its geographic distribution. (3) Involving and engaging stakeholders in the conservation of the Montseny brook newt. (4) Eliminating or minimizing threats that exist in the riparian habitat. (5) Establishing proper legal coverage and defining long-term strategic planning. The successes and failures experienced throughout the process provide us with essential information that will enable us to develop an adaptive management of the habitat. In order to eliminate or minimize threats to the newt’s habitat, some of the actions that are currently being carried out are: (a) Land acquisitions and land exchanges with private properties. (b) Land stewardship procedures, with two custody agreements being signed. (c) Reduction of water withdrawal with nine water catchments and distribution being remodeled. (d) Improvement of water treatments and storage by installing ecological wastewater treatment facilities. (e) Ensuring ecological connectivity and riparian forest restoration. Here, we present an evaluation of the actions carried out to improve the habitat of this species, including the necessary considerations for them to be implemented correctly and to be successful in a natural area, which is under public-private management.

Contributions of Vegetation Greening and Climate Change to Evapotranspiration Trend after Large-Scale Vegetation Restoration on the Loess Plateau, China

Since the early 2000s, the vegetation cover of the Loess Plateau (LP) has increased significantly, which has been fully recorded. However, the effects on relevant eco-hydrological processes are still unclear. Here, we made an investigation on the changes of actual evapotranspiration (ETa) during 2000–2018 and connected them with vegetation greening and climate change in the LP, based on the remote sensing data with correlation and attribution analysis. Results identified that the average annual ETa on the LP exhibited an obvious increasing trend with the value of 9.11 mm yr−1, and the annual ETa trend was dominated by the changes of ETa in the third quarter (July, August, and September). The future trend of ETa was predicted by the Hurst exponent. Partial correlation analysis indicated that annual ETa variations in 87.8% regions of the LP were controlled by vegetation greening. Multiple regression analysis suggested that the relative contributions of potential evapotranspiration (ETp), precipitation, and normalized difference vegetation index (NDVI), to the trend of ETa were 5.7%, −26.3%, and 61.4%, separately. Vegetation greening has a close relationship with the Grain for Green (GFG) project and acts as an essential driver for the long-term development trend of water consumption on the LP. In this research, the potential conflicts of water demanding between the natural ecosystem and social-economic system in the LP were highlighted, which were caused by the fast vegetation expansion.