Biomass loss in village ecosystem due to human-wildlife interaction in Western Himalayan region, India


 Conservation faces the challenge of reconciling human activities with the simultaneous presence of wildlife in cultivated landscapes. In attempt to estimate biomass and associated carbon loss due to the removal of agroforestry trees species the present study was carried out in two villages of Pauri Garhwal. The results revealed that due to human-animal interaction caused substantial biomass loss (7.365 and 2.453 t ha-1) and carbon loss (3.386 and 15.133 t ha-1) in the two studied villages Manjgaon and Mald Bada, respectively. The estimates of the present study demands protecting existing forests and planting trees through reforestation and afforestation as a measure to enhance carbon sequestration capacity. The success of these management practices will depend on the potential to minimise human-animal interactions especially in the fringes of the village community and agricultural landscapes.


Introduction
Human-wildlife interactions due to competition for food and resources, are widespread and have imposed severe costs on both wildlife and people and even extinction of many species ( Human-wildlife interactions are generally more intense those areas, where agricultural practices along with livestock rearing are main components of rural people's livelihood and income (Mojo et al. 2014;Li et al. 2013;Treves et al. 2006). Rural inhabitants, especially agricultural producers and forest landowners, typically bear the brunt of wildlife damage (Conover 1997). Losses from human-wildlife interactions can be relatively small at the group, village or district level, although an individual farmers can lose a considerable proportion of their potential harvest in a season or year (Hill 2000).Crop raiding by wildlife thus has a signi cant impact on rural people's livelihood, forcing them to adopt illegal practices to minimise this impact. The extent of farmers' tolerance to crop losses due to wildlife is in uenced by their dependence on farming for income, size of land holding, length of residence in an area and presence/absence of effective compensation schemes (Hill 2004).
Sometimes the negative impacts of human-wildlife con icts on the environment and wildlife conservation activities include the clearing of vegetation on private land to reduce the habitat of nuisance wildlife, resulting in lower wildlife numbers (Treves et al. 2006). Possible con ict management measures range from relocation of wild animals to destruction of their habitat, including felling of trees providing shelter to the wild animals causing problems (Madhurima and Banerjee 2013). Further research is urgently needed to determine the scale and extent of these environmental problems and identify whether they are speci c to areas with human-wildlife con icts.
At present, the co-existence of monkeys with humans is topic of threat due to growth in both the human and monkey populations (Das and Mandal 2015).Monkeys are well adapted to co-exist with humans and thrive near urban and agricultural human settlements due to the plentiful supply of food from agricultural lands (Sabic 2011;Cawthon 2005). Similarly to humans, they have a non-specialised and very exible diet and can survive even in degraded habitats or urban areas, where they feed on whatever humans eat (Campbell et al. 2011). During food scarcity, monkeys are adapted to wide variety of foods, including bark and cones of conifers (Sabic 2011). Co-operative behaviour, an opportunistic lifestyle and a nonspecialised, omnivorous diet have helped primates to become highly adaptable and live alongside humans in rural, urban and semi-urban areas (Hill 2000;Pirta et al. 1997). Monkeys in search of their food can create problems for humans, such as damage to crops, fruiting trees and snatching goods and food.
With the expansion of human settlements and associated shrinking of natural habitats (Fuentes 2006)many monkeys have become ecological refugees (Mitra 2000). In India, compensation of Rs 0.2 million is paid by the Uttarakhand state to victims of monkey bites (GoUK 2014).
In the mountain villages of Western Himalayan region of India, the con ict between monkeys and humans have accelerated in recent decades. Monkeys are creating problems for the villagers such as destroying crops and fruits, and sometimes injuring children. In response, the villagers have attempted to manage the con ict by destroying the monkeys' habitat. One of the management options available is felling/pruning of trees that the monkeys use as shelter on farms as also discussed in a study by Mojo et al. (2014).This practice has resulted in biomass extraction and associated carbon losses, i.e. environmental degradation. The loss of carbon from the eld has a bearing on global efforts to mitigate climate change, including the United Nations programmes on reduction of emissions from deforestation and forest degradation (REDD+). Human-wildlife con icts are a potential barrier to effective, natural resource management and livelihood improvement and more efforts are needed to be made by local government and development organisations to investigate the problem and mitigate the effects (Hill 2004). However, there is currently a lack of information and research on plant biomass losses due to human-wildlife con icts. Thus there is a need of policies for proactive and reactive responses (Athreya and Belsare 2007).
The aim of this study was to estimate the standing biomass and the associated carbon losses due to felling/pruning of 10 most common local tree species in response to human-wildlife interaction. The intention was to improve understanding of carbon storage and forest management practices adopted by rural communities, and hence the REDD+ programme.

Study Area
Pauri Garhwal, a district in the state of Uttarakhand, in Western Himalayan region encompasses an area of 5230 km 2 and is situated between 29°45' and 30°15' N, 78°24' to 79°23' E with sub-tropical to temperate climate. Monthly minimum and maximum temperature in the study area ranged between 6-21°C and 18-35°C, respectively, with mean annual rainfall of 1500 mm, while the soil is derived from weathering of slate down to 30-80 cm deep. The main occupation of the local inhabitants is farming, while other major sources of employment for young people are armed forces and teaching. Due to the lack of infrastructure and geography of the area, there are no major industries in the hilly part of the district (MSME 2016).

Data collection
Collection of primary data was carried out using a pre-tested semi-structured questionnaire was framed based on reviewed literature, previous knowledge, a pilot survey and peer discussions during 2011-2012. The questionnaire included a mix of questions pertaining to the issue under investigation, with the majority being closed-ended questions. The information was collected by personal visit to the study area and discussion with respondents (local inhabitants) with their prior oral consent. The responses to the questionnaire provided data on household attributes, crops grown and factors responsible for biomass extraction. The interviews and discussions with peers and locals (mainly elderly people and women) lasted for one hour and were conducted in Hindi as well as local dialect (Garhwali).

Biomass estimation
The aboveground biomass was calculated using existing volume regression equations for Toona ciliata, Quercus leucotrichophora and Bauhinia variegate ( Table 1) (FSI 1996; FSI 2015).The aboveground biomass values for remaining tree species such as Celtis australis, Ficus palmata, Ficus roxburghii, Grewia optiva, Sapium insigne, Pistacia integerrima and Prunus cerasoides were estimated using the formula for standing trees, with the results expressed in m 3 (Chaturvedi and Khanna 1982). The diameter at breast height was measured with a calliper and tree height with a Ravi multimeter.
Calculation of aboveground biomass for remaining species was as follows: The basal area(Ab) of merchantable bole was estimated as: Where,π = 3.14 and d is the diameter of the tree at breast height.
The volume (V) in m 3 was calculated as: Where, H is tree height and BEF is biomass expansion factor used in an Indian context (value 1.575; Kishwan et al. 2009).
Using mean wood density (MWD)of each species, total biomass was calculated in metric tonnes (Rajput et al. 1996). The MWD value of 0.72 was used for species for which the exact MWD was not known (Kaul et al. 2009). The calculated volume of the trunk was used to estimate total trunk biomass (kg) by multiplying with wood density (WD) for the corresponding tree species following Brown (1997):

Assessment of Carbon Stocks
To estimate the carbon content of trees in the study area and total biomass extraction, samples of wood were taken from felled trees of the different species. The ash content method was used to estimate carbon content following Negi et al. (2003), due to its simplicity and the availability of resources such as equipment and research expertise. Twenty samples were taken from each tree species and ground into powder using an electric pestle mortar. The powder samples were sieved and oven-dried to constant weight and then a 2g sub-sample of each was transferred to an uncovered crucible, which was placed in a mu e furnace and heated at 575 ± 25°C for 3 hrs to eliminate the carbon. The crucibles were then placed in desiccators for cooling, to avoid moisture absorption (Ehrman 1994). Finally, the weight of ash was measured after the crucibles has attained room temperature and carbon content (%) of the original sample was calculated following Negi et al.

Results And Discussion
Due to long prevailing problem with monkeys, tree felling was conducted in Manjgaon and Mald Bada villages. The decision on tree felling was made by the villagers in a village panchayat. Felling/pruning of trees around agricultural elds and nearby areas was expected to yield a new ush of green tree foliage that could be used as fodder and fuelwood, which in turn could increase the productive land for agriculture and to get rid of monkeys. The major tree felling was concentrated to the agricultural elds rather than forested or fallow land around the villages. The intensity of felling was greater in Manjgaon including parts of the nearby forest, as the monkey problem was perceived to be more severe in Manjgaon, because the agricultural elds were closer to the forest where monkeys sheltered at night. The felling was carried out by contractors and the total expenditure on the task was around Rs. 22,000, with some other expenses such as cutting and logging. Most of the logs were used by the villagers for making furniture, as sleepers and as fuelwood ( Table 2). According to the villagers, management practices such as lopping and cutting of branches was done for fuelwood and timber as well as to obtain green ush from fodder trees.
In order to identify the reasons behind the large-scale tree felling, villagers in three different age groups (<25 years, 25-60 years and >60 years) were surveyed. All age groups had the same view regarding the tree felling operations. The main reason was the problem with increasing number of monkeys in the past few decades. People older than 60 years were particularly unhappy with monkeys, reporting that they had destroyed crops in their agricultural elds over the past two decades. Once the monkeys reach to the agricultural elds, they raid any crop available and left nothing. Regardless of the crop grown, or sown, in the agricultural elds or in gardens near villagers' houses, it was often destroyed by the monkeys. The monkeys frequently roam around the agricultural elds in the mornings /evenings and at night they roost in nearby trees. As the problem persisted over time, the villagers resorted to fell the sheltering trees.
According to the villagers, two groups of monkeys with approximately 25-30 individuals in each group resided in the area and tend to visit the agricultural elds at different times. The villagers reported an increase in monkey population over the past few decades. Destruction caused by monkeys in farmers' elds is a common phenomenon in many areas of the world (Das and Mandal 2015;Fuentes 2006;Chalise et al. 2001). Incidences of scaring people by aggressive behaviour such as snarls and occasional bites has also been reported by Imam and Ahmad (2013). The monkeys in the study villages had been present since long time, but previously restricted to the forested area and visited the agricultural elds occasionally. The main agricultural crops raided by monkeys were reported to be rice, wheat, pulses, maize, and millet. Incidences of eating fruits grown near houses and occasional food stealing from houses has been reported for chimpanzees in Uganda (McLennan and Hill 2012). Damaging of houses by jumping on the roofs of houses and some incidents of monkeys biting humans were also revealed by the rural inhabitants. Such threatening behaviour by primates towards humans, especially children, has also been identi ed as a major problem in Africa (McLennan and Hill 2012). With the expansion of human settlements and consequent decline in habitats, as well as degradation of local forests, many monkeys have become ecological refugees (Mitra 2000).

Biomass extraction
Total biomass extraction due to human-wildlife con ict in the study area was estimated to be 5.640 t ha -1 fallow land and 1.725 t ha -1 agricultural land in Manjgaon village, and 1.108 tha -1 fallow land and 0.845 t ha -1 agricultural land in Mald Bada village (Table 3). Maximum carbon stock loss was calculated to be 9.918 t ha -1 fallow land and 5.2 tha -1 agricultural land in Mald Bada and 2.593 t ha -1 fallow land and 0.793 t ha -1 agricultural land in Manjgaon (Table 4).
Maximum mass extraction of different tree species was lower in Mald Bada. The rate of removal from agricultural land was 0.592, 0.166, 0.099 and 0.026 t ha -1 for C. australis, G. optiva and P. cerasoides and was lowest (0.004 t ha -1 ) for P. integerrima (Figure 2).For fallowland, maximum biomass extraction rate was 0.880 t ha -1 for C. australis, 0.254 t ha -1 for G. optiva, 0.238 t ha -1 for P. cerasoides, 0.165 t ha -1 for P. integerrima and 0.071 t ha -1 for F. Roxburghii, in Mald Bada.
The maximum carbon loss from harvest of tree species in Manjgaon was for C. australis followed by T. ciliata and Q. leucotrichophora on agricultural land and for C. australis followed by T. ciliata and B. variegate on the fallow land. In Mald Bada, C. australis removal represented the maximum carbon loss from both types of land, followed by G. optiva and P. cerasoides (Figure 3).Tree felling was carried out in both villages, but the felling in Manjgaon included part of the nearby forest near the agricultural elds where the monkeys roost at night. This explains the large scale of tree felling in Manjgaon and associated greater loss of carbon.

Conclusion
The presence of tree species in and around agricultural areas plays an important role in carbon sequestration (Mojo et al. 2014). However, tree felling by local villagers to combat the problem of raiding monkeys can cause substantial carbon losses, as demonstrated in this study. To overcome such hidden impacts of human-wildlife con icts, inhabitants in regions experiencing such con icts could plant fruit trees inside or near the boundaries of forests, in order to provide su cient food stock for wild animals and minimise their raids on agricultural elds.
Protecting existing forests and planting new forests through reforestation and afforestation are important measures to enhance carbon sequestration capacity. To reconcile forest conservation and livelihood improvement under emerging global strategies such as REDD+ and climate-compatible development (CCD), it is necessary to acknowledge the socio-economic complexities of forest resource management and design effective management interventions (Entenmann et al. 2014).Speci cally, the importance for the success of REDD+ initiatives of speci c management measures to minimise human-wildlife con icts has been stressed (Entenmann et al. 2014) and were also demonstrated in the present study. However, the success of such management practices will depend on the possibility to minimise wildlife con icts with rural inhabitants.

Declarations
Compliance with Ethical Standards

Funding
No funding was provided to carry out this research.

Con ict of interest statement
The authors declare that they have no con ict of interest.  Figure 1 Location map of study area.  Quanti cation of carbon (t ha-1) sequestered in harvested tree species.