El Salvador is one the Latin-Americans countries that presents high deforestation and continuous decrease of the water availability on the last decades owing to several aspects (decrease of rain, climate change impacts, pollution, increase temperature and evapotranspiration, and the land use change as one of main causes). This issue increase the water use intensity in the country and its position is very near to the hydric stress, which it´s possible to reach on the next years.
Taking in account this issue, the research carried out it have aimed the hydrological analysis to determinate the implications and affectation level in the reduction of subsurface flows and surface water resources as water springs and ecological flows, which is arising from deforestation processes and land use change in essentials water recharge areas that supply tributary rivers and water fountains which are also sources of drinking water for local people.
The methodology applied was by means of Hydrological model (rainfall-runoff) to calibration and simulation processes of the water cycle in some basins and through apply the method. “Soil Conservation Service (SCS)” to determinate the different scenarios about “the abstraction" or "infiltration” of surface runoff (mm) taking in count the kind of soil, land uses and hydrological parameters.
The flows from different water fountains in certain seasons were measured and related with the percentage of existing forests in the watershed by mean correlation equations, taking into account also the kind of edaphological soil and physiographic conditions. The Hydrological model was calibrated and simulated with the measured flows, land uses and the hydrological cycle parameters. The curve and correlation index between water yields (liters/Ha) and percentage (%) of existing forest land were obtained for the same soil kind and the same meteorological conditions.
Some aspects It was found, on average that watersheds which have gradually lost their permanent cover forest from 60% to 15%, have submitted correspondingly, a decrease in water springs of 85% compared to their initial conditions a few decades ago.
Another aspects It was found that an increase in the forest land use in upland watersheds, reaching on average 50% of the watersheds extension (ha), could be possible to get on average a decreased from 14% - 20% of surface runoff of the rain in relation to surface runoff (mm) under current conditions.
Furthermore a decrease in the surface runoff equivalent to 50% - 60% of precipitation (mm) used for the analysis. That is the 50% of the rain represents the abstraction or infiltration could be reach with a increase the forest land on a similar per cent over the currently conditions.
From the result, was proposed a recovery strategy by raising the "abstractions or infiltration" in order to increase the water potential of the springs and generate a decrease in surface runoff from the direct rain and promote a sustainable development in El Salvador.
The Little Andaman Island within the Andaman archipelagos in the Bay of Bengal Sea of India, possess luxuriant tropical evergreen rainforests which is home to a large number of rare, endangered, even undocumented species of flora and fauna. It is homeland of the indigenous hunting and gathering Onge tribal community who have sustained with their deep ecological knowledge of this island ecosystem. According to the climatic phenomena, availability of freshwaterphysical and hydrological regimes and associated natural resources they have categorised their island into several Eco-scape regions through mental maps. This research work has been an attempt to detail the chronological impact of the unprecedented mainstream developmental strategies within such a tropical island ecosystem.
After Indian independence (1947) there was a huge demand for space and forest resources to rebuild the nation. Since then this island along with the other islands of this archipelago has been taken up by the Indian administration to carry out several developmental strategies. The chronological impact of the unmatched policies within this island ecosystem is explicit in the physical environment as well as the socio-cultural aspects of the Onge.
Historical backdrop of the island is interpolated from literature reviews.Anthropological and sociological documents are studied to understand the condition of the Onges before and after the Island was opened for the mainstream society. The phase wise impact of the developmental strategies on the physical and social fronts are studied in details.
The first step of the developmental policies was to clear the dense forest for rehabilitation of the excess mainland population. Timber harvesting, construction of dams, erecting 1200m long wharf cum jetty into the sea, quarrying activities, exotic red oil palm plantation, oil mills, rehabilitation programmes and many more came up sequentially which are sufficient to harm the island’s physical environment.
The aforesaid activities also hampered the Onge’s socio-cultural perspective resulting in a drastic decline of their population. Their ecological knowledge in understanding the island ecosystem was never considered. The last decade came up with certain environmental protection act that banned some exploitative practices within the island ecosystem. But for the sustenance of the already rehabilitated population further newer aspects of policies are being adopted. So, it is seen that this island is treated on a trial and error basis without any a-priori impact analysis.
Implications of the study
This research assessment details the problem of resource utilisation process within a remote tiny island ecosystem recognised as a bio-diversity hotspot along with its native tribal community. When any virgin region comes within the arena of development, it cannot be ceased all of a sudden as the change brought to the region becomes a process.
This study is helpful in detecting the areas where improvements are necessary and restrictions should be firm. The author would like to infer her humane suggestions to synergise the tribal Eco-scape perception and knowledge with the mainstream planning schemes to maintain the Island carrying capacity.
Ecological engineering can be defined as the designs and actions using and/or acting for nature. It is a part of Nature-Based Solutions (NBS). It brings the fruits of research to the field management of water and terrestrial ecological systems. The questioning of the scientific and practice spheres allows in particular better identifying the multiple benefits that natural habitats and populations derive from ecological engineering actions. An important issue for the actors of this field remains today to highlight the whole benefits and ecosystem services related to its use, by showing the ecological, economic and social plus-values of these kinds of projects. Such new approaches call for questions to researchers and innovation to practitioners, with the necessity to design ecological engineering actions combining approaches by and for life, in particular by reconciling natural hazard control and land ecological restoration in water ecosystems. The objective of this presentation is to show how research, especially in the fields of geosciences, restoration ecology and engineering ecology, can be used in an interactive process with practitioners for defining ecological engineering principles devoted to reconcile both natural hazard control (erosion, inundations…) and land ecological restoration in water ecosystems. To illustrate this, the case of soil and water bioengineering as ecological engineering solution will be presented. It represents the implementation of techniques using plants and their mechanical and/or biological properties for: 1/ natural hazard control, 2/ ecological restoration, rehabilitation or renaturation of degraded lands and environments. Finally, the presentation will focus on the links between science, practice and policy in these fields, with emphasis on the situation in France.
The increase of the burden on environment caused by development and climate change has affected wild species habitat. To make effective strategy to conserve freshwater ecosystem and biodiversity, knowing a species distribution or total biomass in large area can be important information. For this aim, monitoring method is usually based on visual detection, counting or trapping; however, these traditional monitoring methods have difficulties of time consuming, monetary and human costs. Furthermore, these methods have been applied limitedly to qualitative information such as exist or absent research, and it is difficult to estimate potential biomass through the upstream and the downstream of rivers. These days, environmental DNA (eDNA) analysis has been known as novel molecular technique and it can lead to the solution of these problems. eDNA means the DNA which can be extracted from environment such as water bodies, and it originates from animal metabolite like the feces, saliva or skin cells. It enables to detect the presence of species specific base sequence of DNA, and can be expected to have considerable advantage to estimate the presence and population of a species. eDNA study has been promoted in experimental aquarium and closed water area such as pond, lake, and small lagoon. From these studies, it is revealed that eDNA is degraded by bacteria or DNAase in water bodies, and collapsed by UV, chemical substances and there is a positive correlation between the number of eDNA copies and biomass or density of individuals. On the other hand, eDNA study in a river is limited because its various environment and physical condition and the effect of advective diffusion make it complicated. Moreover, the studies are mostly focused on specific rare species or important species for fishery resources; however estimating the mass of the bottom of ecological pyramid (i.e. algae, primary producer and aquatic invertebrates, primary consumer) is a key to comprehensively understand and manage a river ecosystem.
In this study, we applied an eDNA approach to invertebrates and revealed longitudinal and seasonal profiles of the eDNA in the Hirose River, Japan. For this aim, we conducted sampling and quantitated the mass of eDNA using qPCR. We sampled 2L of stream water at three reaches of up-, middle- and downstream whose land uses consist of different properties (i.e., forested, agricultural, and urbanized) once per a month along the river through August to December 2015. As the primers for PCR, we focused on the detection of mitochondrial DNA, cytochrome b gene, which is able to detect universal gene area for almost all invertebrate species. Using the result, we can assess the river environment to discuss river design in the future and to consider the relationship between flood and environment. Furthermore, it is indicated that eDNA also can extend the possibility of continual survey to evaluate wasted water and land use change.