Identification of Non-Impact Livelihoods on Mangrove Resources in Can Gio, Vietnam

There are several negative impacts on mangrove resources related to 11 existing livelihoods in Can Gio district, where socio-economic development has created many changes in livelihood conditions and ecological environment of the mangrove forests [1]. As a result, the study focuses on identifying and selecting livelihood types that have no impacts on mangrove resources based on primary data collected from 537 structured questionnaires and 45 in-depth interviews with experts, forest keepers and local households about understanding of the activities of 11 current livelihoods and environmental conditions of the study areas in the past 10 years. Qualitative data analysis, non-impact livelihood scale and AHP analysis allow the analysis and identification of 6 livelihood types appropriate for the goal of avoiding mangrove resource degradation to conserve, maintain, and sustainably develop mangrove ecosystems for Can Gio Mangrove Biosphere Reserve.


Introduction
Mangrove forests can be affected at many levels from local, area, regional to global levels.According to FAO [2], about 20% of the world's total mangrove forest area was destroyed in the 1980s and by the 2000s, about 35% of the world's total mangrove forest area disappeared.This was attributed to a range of factors such as population growth and urbanization, expansion of aquaculture area, agricultural and fishery waste, construction waste, tourism, climate change including sea level rise [3] etc.As shown in previous studies [4], [5], [6], many impacts on the environment and ecosystems of Can Gio mangrove forests are related to 11 types of livelihoods that cause biodiversity loss of in mangroves such as logging, pollution due to aquaculture activities, illegal fishing, and water pollution from urbanization-industrialization [7,8] etc.The influence of livelihoods on mangrove forests occurs at different scales, depending on the level of exploitation such as selfsufficiency, traditional and industrial-scale exploitation with all of them affecting mangrove forest habitats All the factors that cause negative impacts on mangrove resources from livelihood activities result in reduction of forest area, biodiversity loss and long-term consequences as forest degradation and imbalance of natural environment [9].Therefore, the identification and selection of livelihood models without impacts on mangrove resources ensure the stability and sustainability of the mangrove ecosystem based on the positive factors of the livelihood types being applied in the core, buffer, and transition zones.
The development of spatially related livelihood benefits associated with mangrove ecosystems can also assist local authorities and the mangrove management board to maintain and protect the mangrove system and help address problems of inappropriate livelihood scale in the core, buffer, and transition zones.However, very few studies so far have identified existing livelihoods with little or no impact on mangrove ecosystems to serve the selection of feasible livelihoods [10,11].Many authors point out the lack of effort, progress, and support in developing sustainable livelihood models for mangrove ecosystems [12,13,14], while others point out the lack of integrating livelihood types that have no impacts on mangrove resources, as well as lack of efforts to conserve and restore mangroves based on the adjustment and improvement of adequate livelihoods [15,16,17].Finally, the most recent assessment of the mangrove status in Vietnam shows that the selection of preferred livelihoods associated with conservation of mangrove ecosystem resources is necessary to achieve long-term sustainability for mangrove forests [18,19,20] To evaluate and identify non-impact livelihood types that do not cause degradation of mangrove resources, a set of criteria for sustainable livelihoods [21,22,23] is utilized.At the same time, the qualitative and hierarchical analysis approaches allow to identify the appropriate livelihoods for the goal of avoiding mangrove resource degradation [24,25].

Data
Secondary data collected over the period 2010-2020, relevant policy documents, economic models, and stakeholder opinions on the possibility of non-impact livelihoods on resources and the environment of the mangrove ecosystem were reviewed and analyzed in 2020 (from November 2019 to June 2020).

Methods
The method of collecting opinions and information from relevant stakeholders includes three stages i) identifying interviewees (households as forest keepers, mangrove researchers and management board, local people), ii) identifying non-impact livelihoods on mangrove resources (11 out of 14) and iii) assessing the response of the interviewees to develop the non-impact livelihood scale (NiLS) on the mangrove resources through ranking information from 3 interviewee groups.Although livelihoods can vary widely in the same area, we try to assess the livelihoods of rural households without impacts on mangrove resources and explore how they affect the selection and rank the influence levels for the core, buffer, and transition zones.The types of livelihoods interviewed are ranked in terms of importance by building an evaluation matrix to identify non-impact livelihoods based on the criteria of previous studies [4, 5,6].It is more likely that the change in ranking is due to the opinions of the interviewees.The classification method to identify the levels [26] of different non-impact livelihoods on mangrove resources based on statistical responses from 3 groups (households as forest keepers, mangrove experts, and farmers) as follows: Total number of opinions for identification of non-impact livelihoods = NiLS1 + NiLS2 + NiLS3+…..+ NiLSi NiLS1= livelihood identification level of forest keepers NiLS2= livelihood identification level of experts and mangrove management board NiLS3= livelihood identification level of farmers In which, non-impact livelihood scale NiLSR = Non-impact livelihood Rank (NiLSR) × percentage of interviews

-Determine the factor weights
On the other hand, to determine the priority ranking for selecting non-impact livelihood models on mangrove resources, the AHP method [27] is applied based on a set of indicators (table 1).Two livelihood selection objectives C1 and C2 having no impact and impact on mangrove resources are based on 5 criteria identified from the interviews to decide which livelihood models are suitable for the above two objectives: no impact on the environment (P1), conservation of mangrove resources (P2), Economic activities (P3), social activities (P4) and institutions and policies (P5)

Criteria Indicators Scale
No impact on the environment (P1) Maintaining long-term resource productivity 1-5 No changes to the environment 1-5 No changes in biodiversity Increase/Decrea se Source: Analyzed results from the field survey and interviewed households based on the sustainable livelihood framework DFID (1999) The matrices are developed with two objectives to select factors related to livelihoods without impacts and livelihoods with impacts on mangrove resources, and are evaluated based on the criteria in Table 1.Information is collected from interviews with 3 groups mentioned above to analyze the importance of 5 factors and determine the scale for each type of livelihood.The ranking criteria are assigned with specific values, forming the matrices (C1) 5 × 5 and (C2) 5 × 5 [28,29] based on independent questions to establish the comparison matrices as follows: Since matrix A has two elements, it requires a consistency check to comply with the consistency principle.The eigenvalue principle is λmax = 2 with eigenvector as W = [W1, W2] T = [0,25, 0,75] T respectively.

Analysis of non-impact livelihoods on Can Gio mangrove resources
Based on the survey results of 11 livelihood types in 4 communes of Can Gio district including Binh Khanh, An Thoi Dong, Tam Thon Hiep and Ly Nhon in the core, buffer, and transition zones, all three groups of interviewees agree that there is a transition from traditional aquaculture to high-tech aquaculture.According to experts, traditional aquaculture and agricultural livelihoods have changed the coastal natural environment, affected the quality of water and soil resources, and unbalanced the Land use policies to support non-impact livelihoods on mangrove resources 1-5 Support policies for non-impact livelihoods on mangrove resources 1-5 People's compliance with the law 1-5 mangrove ecosystem.Survey results and expert interviews indicated that the shrimp farming livelihood (extensive, semi-intensive and intensive farming) has a relatively large impact on the mangrove ecosystem, and results in severe pollution of the natural water environment.
Results in Table 2 show that aquaculture with natural food from mangroves is a type of livelihood with little impact on mangrove resources in the core and buffer zones, which is highly appreciated by forest keepers, experts, and authorities (17.8%).Meanwhile, only 11.1% of interviewed farmers have similar opinions, proving their lack of understanding and awareness of the non-impact livelihoods on mangrove resources.
Besides, the rate of agreement between forest keepers, experts, and management board for ecotourism livelihood as a non-impact livelihood on mangrove resources is 20%.This is because Can Gio has a diverse population of terrestrial and aquatic fauna and flora species formed on large deltas of estuaries.Moreover, Can Gio Mangrove Biosphere Reserve is also recognized by UNESCO as the most typical biosphere reserve in the world and one of the key tourist areas of the city.Additionally, Can Gio is also one of the first biosphere reserves in Vietnam, known as the "green oasis" of the city with pristine mangrove resources, typical landscape of coastal wetland ecosystems, and comparatively good environment.However, only 6.7% of farmers agree that the ecotourism livelihood has no impact on mangrove resources.This shows that farmers are less interested in this livelihood and think it is imposed by the authorities and management board because they do not have access to the strictly protected mangroves forests.
In addition to the two types of livelihoods with low impact on the mangrove environment, relevant stakeholders also agree that lagoon crab farming and oyster farming have little impact on the mangrove ecology and environment.Furthermore, the livelihoods of fish cage farming, fish farming in ponds, swiftlet farming, and orchard farming also have little impact on mangrove resources because these types are mainly distributed in buffer and producing zones.
There is a difference in the assessment of the impact on mangrove resources of high-tech shrimp farming between forest keepers (2.2%), experts (6.4%) and farmers (15.6%).Forest keepers express that the core and buffer zones are strictly protected areas so the emergence of this livelihood in these two areas will reduce the mangrove forest area.While the authorities and experts said that this livelihood need to be better managed in terms of technology so as not to cause pollution.Farmers' opinion is that this type of livelihood will not affect mangrove resources because they have applied new technologies to ensure that they do not pollute water sources and reduce impacts on land resources.
Through consultation with experts and authorities, ecotourism is considered as a type of livelihood for sustainable development in the future.Nevertheless, according to the interview results with farmers, most of them do not participate in this livelihood currently because activities related to mangrove ecosystems are strictly controlled and only the Forest Management Board and state organizations participate.Therefore, the type of livelihood associated with ecotourism in the locality still has a lot of potential for development, especially the type of ecotourism combined with homestay will help improve incomes, create jobs for locals and diversify livelihoods for Can Gio.The meta-analysis of evaluation opinions in Table 3 shows that relevant stakeholders express good opinions about 2 types of non-impact livelihoods on Can Gio mangrove resources which are aquaculture with natural food from mangroves and ecotourism (Table 3).Stakeholders also agree that tourism will be one of the main livelihoods of the local people in the future as this area has the advantage of availability of natural resources from mangroves.Stakeholders also identify 2 types of livelihoods including orchard farming and salt production that are likely to affect mangrove resources due to the expansion of farming areas.
The study shows that the lagoon livelihoods in the core and buffer zones, which are assessed to be quite safe for the mangrove ecosystem, do not affect and degrade mangrove resources.Regarding oyster and crab farming, stakeholders also assume that these two types of livelihoods mostly use natural food sources and cause little environmental pollution, so they have a high level of safety for the mangrove ecosystem without affecting and degrading mangrove resources.
In addition, stakeholders also say that the livelihoods of fish cage farming, fish farming in ponds, swiftlet farming and orchard farming do not cause impact and degradation for mangrove resources.Since most of the farming area is not in the core or the buffer zone with safe distance, there is no direct use and exploitation of mangrove resources.The scale of non-impact livelihoods on natural resources: 1: Strong impact; 2: Little impact; 3: No impact.

Conclusions
The results of this study have identified 6 types of non-impact livelihoods on mangrove resources according to a 3-level scale, thereby helping us to better understand the types of livelihoods and the level of impact on the exploitation of mangrove resources.Identifying the non-impact levels of livelihoods on mangrove resources is of paramount importance to maintain and develop mangrovebased livelihoods in Can Gio.The livelihoods that are assessed as very good do not cause impacts on mangrove resources, and need to be implemented in association with local communities in the long term.
In addition, the research results have shown an overall picture of the impact of each type of livelihood on the resources of the Can Gio Biosphere Reserve.However, the limitation of the study is that it mainly focuses on analyzing and collecting opinions from 3 groups including forest keepers, experts and farmers on factors that do not affect mangrove resources, and also that very few evaluation indicators assess impact on other environmental components (soil, biodiversity).Therefore, there is a need for studies to evaluate the effects of different types of livelihoods on other environmental components in order to have a better understanding of the scale of impacts of human activities on environmental components in the Can Gio Mangrove Biosphere Reserve.The results also support the development of a plan to conserve mangrove resources.

Table 2 :
Non-impact livelihoods on mangrove resources

Table 3 :
Synthesized scale of non-impact livelihoods on Can Gio mangrove resources

Table 4 .
The weights of the five criteria and the consistency index

Table 5 .
Types of non-impact livelihoods on mangrove resources determined according to the scale in Can Gio Biosphere Reserve