Can Anthropization Govern the Variation in Water Table Levels, Water Flow and Carbon Losses? A Case Study in Tropical Mountain Peatlands an Serra Do Espinhaço Meridional, Minas Gerais, Brazil.

Peatlands are ecosystems formed by organic matter (~ 15% of the total mass) and water (~ 85% of the total mass), and constitute a particular type of free aquifer. They perform important hydrological functions by storing excess water during rainfall events, contributing to the baseflow of its rivers throughout the year. Degradation affects the dynamics of the water table, which, in turn, can influence the decomposition of organic matter content and the release of carbon into its waters. Its water retention capacity may also be compromised and reduce the volume of water available downstream, especially in the dry season. The aim of this study was to evaluate the effects of anthropic interference on variations in groundwater, water storage, and carbon flow in two tropical mountain peatlands, located at the head of the Araçuaí River, in Serra do Espinhaço Meridional (SdEM), Minas Gerais, Brazil. Groundwater levels were installed in piezometers distributed on a peatland located in a protected area (Natural Park) (Protected - TP) and in a peatland located outside the conservation unit (Anthropized - TA). Data were analyzed considering the daily rainfall recorded by an automatic weather station installed in the study area. From the data on precipitation and water table level variation, the specific yield (Sy) in the two peatlands was calculated. The observed flows and the mean monthly Sy on each piezometer were correlated and their significance was verified using the t test (p <0.05). The relationship between the observed flow and the mean monthly values of Sy obtained for the piezometers were verified through multiple regression. The specific yield correlated significantly with flow in both peatlands (p < 0.05). Multiple linear regression showed a coefficient of determination (R2) of 0.92 in both peatlands, indicating a direct relationship between Sy and observed flow. The TP presented a 43% smaller variation in the water table, a 7% higher specific yield and a specific flow rate of 13% higher in relation to the TA. The peatland located in a protected area retains more water, with less variation in flow throughout the year, and has less carbon output in the water compared to the anthropized peatland. The results demonstrated that anthropization is causing degradation of the peatland, reducing its water holding capacity and accelerating its carbon losses. In the medium term, these effects may lead to a drastic reduction in flow in the upper course of the Araçuaí River.

Biodiversity and ecosystem functions depend on environmental conditions and resources rather than the geodiversity of a tropical biodiversity hotspot

Biodiversity and ecosystem functions are highly threatened by global change. It has been proposed that geodiversity can be used as an easy-to-measure surrogate of biodiversity to guide conservation management. However, so far, there is mixed evidence to what extent geodiversity can predict biodiversity and ecosystem functions at the regional scale relevant for conservation planning. Here, we analyse how geodiversity computed as a compound index is suited to predict the diversity of four taxa and associated ecosystem functions in a tropical mountain hotspot of biodiversity and compare the results with the predictive power of environmental conditions and resources (climate, habitat, soil). We show that combinations of these environmental variables better explain species diversity and ecosystem functions than a geodiversity index and identified climate variables as more important predictors than habitat and soil variables, although the best predictors differ between taxa and functions. We conclude that a compound geodiversity index cannot be used as a single surrogate predictor for species diversity and ecosystem functions in tropical mountain rain forest ecosystems and is thus little suited to facilitate conservation management at the regional scale. Instead, both the selection and the combination of environmental variables are essential to guide conservation efforts to safeguard biodiversity and ecosystem functions.

A synthesis and future research directions for tropical mountain ecosystem restoration

Many tropical mountain ecosystems (TME) are severely disturbed, requiring ecological restoration to recover biodiversity and ecosystem functions. However, the extent of restoration efforts across TMEs is not known due to the lack of syntheses on ecological restoration research. Here, based on a systematic review, we identify geographical and thematic research gaps, compare restoration interventions, and consolidate enabling factors and barriers of restoration success. We find that restoration research outside Latin-America, in non-forested ecosystems, and on socio-ecological questions is scarce. For most restoration interventions success is mixed and generally limited by dispersal and microhabitat conditions. Finally, we propose five directions for future research on tropical mountain restoration in the UN decade of restoration, ranging from scaling up restoration across mountain ranges, investigating restoration in mountain grasslands, to incorporating socio-economic and technological dimensions.

Land use land cover dynamics through time and their proximate drivers of change in a tropical mountain system: a case study in a highland landscape of northern Ecuador

Tropical mountain ecosystems are threatened by land use pressures, reducing the capacity of ecosystems to provide a large diversity of benefits to people and to be able to achieve them in the long term. The analysis of land use pressures is often superficial and very general, although they are characterized by numerous interactions and strong differences in their local dynamics. We used a variety of freely available geospatial and temporal data and methods to assess and explain patterns of land use land cover (LULC) change, focusing on native ecosystem dynamics, in a sensitive region of the northern Ecuadorian Andes. Our results demonstrate a dynamic and clear geographical pattern of distinct LULC transitions through time, explained by different combination of socio-economic factors, pressure variables and environmental parameters, from which ecological context variables, such as slope and elevation, were the main drivers of change in this landscape. We found that deforestation of remnant native forest and agricultural expansion still occur in higher elevations located, while land conversion toward anthropic environments were observed in lower elevations to the east of the studied territory. Our findings also reveal an unexpected stability trend of paramo and a successional recovery of previous agricultural land to the west and center of the territory which could be explained by agricultural land abandonment. However, the very low probability of persistence of montane forests in most of the studied landscape, highlights the risk that the remnant montane forests will be permanently lost in a few years, posing a greater threat to the already vulnerable biodiversity and limiting the capacity ecosystem service provisioning. The dynamic patterns through space and time and their explanatory drivers, found in our study, could help improve sustainably resource land management in vulnerable landscapes such as the tropical Andes in northern Ecuador.

The structure and diversity of vegetation treelets of tropical mountain forest on mount Bawakaraeng

The study about the diversity and structure of treelet vegetation in three slope areas on the mountainous forest of mount Bawakaraeng, Regency of Gowa, Province of South Sulawesi had been done. There were 17 species of treelets throughout the study area, from 13 families and 16 genera. The Asteraceae family has the highest number of species with 3 species, followed by Fabaceae and Solanaceae which each has 2 species. Pteridium aquilinum, Chromolaena odorata, Breynia oblongifolia, and Pogostemon cablin are the species with the highest important value index. The number of treelet species ranges from 15-16. Treelet species were mostly found in the flat slope area. The Shannon-Wiener diversity index (H’) ranges from 2,033-2,161 and was found to be highest on steep slopes and lowest on flat slopes. The H’ has the same tendency as Simpson’s Diversity Index and Evenness Index of Pielou (E) and reverse relationship with Simpson’s Dominance Index.

A Synthesis and Future Research Directions for Tropical Mountain Ecosystem Restoration

Many tropical mountain ecosystems (TME) are severely disturbed, requiring ecological restoration to recover biodiversity and ecosystem functions. However, the extent of restoration efforts across TMEs is not known due to the lack of syntheses on ecological restoration research. Here, based on a systematic review, we identify geographical and thematic research gaps, compare restoration interventions, and consolidate enabling factors and barriers of restoration success. We find that restoration research outside Latin-America, in non-forested ecosystems, and on socio-ecological questions is scarce. For most restoration interventions success is mixed and generally limited by dispersal and microhabitat conditions. Finally, we propose five directions for future research on tropical mountain restoration in the UN decade of restoration, ranging from scaling up restoration across mountain ranges, investigating restoration in mountain grasslands, to incorporating socio-economic and technological dimensions.

Adapting to Receding Glaciers in the Tropical Andes

Integrated approaches are needed to understand and respond to changes in tropical mountain ecosystems and communities brought about by receding glaciers and changes in land use.