Abstract
A study was conducted to assess the status, ecological diversity, traditional uses, spatial arrangement, and importance of homestead garden for biodiversity conservation of the urban and rural households in Kishoreganj Sadar of northern Bangladesh. Assessment was done by means of multistage random sampling from a total of 80 households using a semistructured questionnaire. A total of 62 plant species belonging to 36 families including 5 threatened species were identified. The majority of the species were used as fruit and food (45%) followed by medicinal plants (38.71%), firewood (32.26%), and timber (29%). Ecological diversity indices indicated that the existing plant species in the homestead gardens in the study area have moderately high biodiversity and species richness. Farmers perceived importance for homestead plant species conservation was for fruit and food (85%) followed by building materials (78.75%), subsistence family income (73.75%), and source of firewood (68.75%). In addition, analysis of existing management regime indicates that growers lack scientific information, almost every household still follows traditional management systems. Finally, a specific homestead forest management plan, conservation of homestead species diversity through scientific management and obtaining training and support from government and NGOs, was found highly demandable by this study.
1. Introduction
Homestead garden is a traditional agroforestry system and an important component in the livelihoods of rural poor, and in the rural economy of the country. During the last 40–50 years, the relative importance has shifted from the traditional forestry to homestead forestry; in such a situation, homestead garden plays a vital role in providing firewood, fodder, medicine, fruit, and timber. It is estimated that about 70% of timber, 90% of firewood, 48% of sawn and veneer logs, and almost 90% of bamboo requirements are met from homestead forests [1].
In Bangladesh, homestead gardens represent a well-established traditional land-use system where natural forest cover is less than 10 percent; homestead gardens, which are maintained by at least 20 million households, represent one possible strategy for biodiversity conservation [2, 3]. The management of the traditional homestead garden has evolved as a response to many factors: cultural, economic and, environmental as well as personal preferences [4]. The conservation of cultivated plants in homestead gardens of Bangladesh not only preserves a vital resource for humankind but plays an important role in household food security, as it is a sustainable source of food, fruits and vegetables [5].
In Bangladesh, there is no specific management plan for the homestead forests [6] which are being traditionally managed by the household owners. Most of the plants grown in homestead garden have multiple uses. These home gardens are some sort of additional income for some families of rural area whereas for most of the families of urban area they act as a medium of nutritional demand fulfill. Millat-E-Mustafa et al. [7] record eight major uses of the homestead forest plants: fruit/food, timber, firewood, spice, fodder, medicine, fencing, and miscellaneous uses. The miscellaneous uses include brooms, handicrafts, shade, ornamental, ceremonial, environmental, and aesthetic. Again, the ecological merits of homestead garden are related to conservation of soil, water, nutrients, and biodiversity [8].
Several studies showed that species diversity in a homestead garden can range from less than five [9–12] to more than 100 [13–15]. In Bangladesh, various studies, for example, [3, 7, 9, 16–23] explore the floristic composition (mainly trees) in the homestead gardens; homestead agroforestry system by [24–26]; homestead plantation and traditional uses by [27, 28]; quantitative structure and silvicultural management by [29–31]; production and services by [32, 33]. Moreover, Motiur et al. [34] studied the role of homestead gardens in rural economy; Alam and Masum [35] and Masum et al. [8] studied the status of homestead garden in an offshore island of Bangladesh, and Akhter et al. [36] studied the role of women in homestead gardens management in the northeastern Bangladesh.
Since the natural forest of Bangladesh is shrinking at an alarming rate due to unprecedented anthropogenic pressure, researchers from across the world have demonstrated homestead gardens’ dynamic role in the conservation of biodiversity and provision of necessary daily needs to rural people by turn for urban people. Researchers from across the country and world have explored the quantitative status of homestead garden but not the driving factors which lead people to plant trees in their house premises. Therefore, this study was conducted to evaluate and quantitatively assess the total botanical diversity and the status of homestead garden ecosystem (both rural and urban), and choice of people, spatial arrangement of different species in both urban and rural homestead areas of Kishoreganj Sadar Upazila (subdistrict) of Bangladesh. The study also tried to find out the reasons towards differences in species diversity and biodiversity conservation for both areas and then represented schematically so that we can understand what are the driving factors behind the differences in both areas (rural and urban). In the study areas, homestead gardens are substantial enterprises and play a significant role in household income.
2. Materials and Method
2.1. Study Area Profile
Kishoreganj Sadar Upazila with an area of 193.73 km2 is bounded by Nandail Upazila on the north, Pakundia and Katiadi upazilas on the south, Karimganj and Tarail upazilas on the east, and Hossainpur and Nandail upazilas on the west. The Main River is Narsunda [37]. Table 1 represents the main features of the study area.
2.2. Research Methods
The study was based on the primary data collected directly from the field during September 2011 to January 2012 through physical measurement. During study, multistage random sampling method was adopted for data collection. From 12 upazilas of Kishoreganj district (administrative unit), Kishoreganj Sadar Upazila was selected purposively. Out of 11 unions in Sadar Upazila, two unions from rural area and only one existing municipality in the study area were firstly selected randomly. Then, two villages from municipality area and one from rest of the unions were randomly selected.
2.3. Data Collection from Respondents
Interviews were conducted targeting primarily old-aged or local experienced persons (usually aged between 30 to 70 years). A total of 80 households, that is, 20 households (PSU, primary sampling unit) with a confidence interval of 33% from each village were selected for interviewing (Table 2). A semistructured questionnaire was used for data collection based on the information collected through reconnaissance and pilot survey. All the species found in each household had been accounted for botanical survey. The final survey and eight focused group discussions (two in each PSU for crosschecked) were completed with the participation and informed consent from the members of the households. Responses to open questions were collected on a variety of demographic and socioeconomic indicators: household species composition, choice of species, cultural activities practices in homestead garden, perceived importance for conservation of species, market access of homestead garden products, and so forth. In order to explore spatial arrangement and respondents’ choice to plant trees in their homestead garden, we have divided the gardens into five different habitats, namely, (front yard, back yard, homestead boundary, that is, adjacent to the dwelling house, pond bank, and road side) for both rural and urban homesteads. On each topic, the respondents were free to express their views.
2.4. Plot Survey
All species present in each sampled homestead garden (average size of 0.05 hectare to 0.25 hectare) were identified and recorded by the botanical name or by local name. All individuals of trees, herbs, and shrubs were counted and recorded except the individuals in hedgerows. No climbers were counted due to the difficulty in differentiating stems. A botanical inventory was conducted only once in each selected home garden. Thus, the seasonal variation in floristic and structure was not assessed. Each species recorded was classified by family, habit (tree, shrub, and herb), and their origin that is exotic or indigenous, and conservation status as followed by [38–45].
2.5. Data Analysis
For the present study, nine ecological indices were used to analyze and to get a clear picture of the species diversity of the study areas, which are listed below. (1)Species diversity index was calculated according to Odum [46]: .(2)Species richness index was measured by Margalef [47]: .(3)The Shannon-Winner diversity index was calculated following Michael [48]: .(4)Shannon’s maximum diversity index was followed by Kent and Coker [49]: .(5)Shannon’s equitability index according to Kent and Coker [49]: .(6)Species evenness index was estimated following Pielou [50]: .(7)Simpsons index was estimated according to Magurran [51]: (8)As biodiversity increases, the Simpson index decreases. Therefore, to get a clear picture of species dominance, is used. (9)Family importance value (FIV) index (the FIV index is used to evaluate floristic composition at the species family level, and it combines richness, density, and dominance) according to the formulae of Mori et al. [52]. (i)Family relative density (%) = (no. of individuals in a family/total no. of individuals) × 100.(ii)Family relative diversity (%) = (no. of species in a family/total number of species) × 100.(iii)FIV is the sum of family relative diversity and relative density.
Where is the total number of species, is the total number of individuals of all the species, is the number of individuals of one species/total number of individuals in the samples.
3. Results
3.1. Status of Homestead Garden Plants
The study survey recorded 62 plant species belonging to 36 families from the set of 80 surveyed homesteads (Table 3). Among the total species, 53.23%, trees, 22.58% shrub, and 24.19% herbs. Amongst the recorded species, 31 trees, 11 herbs and shrubs species were found common both in urban and rural homesteads. Except this, shrub species was higher in urban homestead, tree species was found higher in rural homestead, and in case of herb species was found the same in both areas. Thereafter, out of the recorded species based on conservation status, two species; namely, Alocasia indica and Terminalia chebula are vulnerable, Pteris cretica is near threatened, Boehmeria nivea, Cinnamomum tamala are not evaluated, and the rest of the species are of least concern in the context of Bangladesh.
Floristic composition of the homestead flora consists of both native and exotic species. About 18 species were identified as exotic, and some of them have been domesticated. Recently, fruit-bearing species were gradually being replaced by some exotic timber species such as Bauhinia acuminate, Albizia saman, Swietenia mahagoni, Tectona grandis, and Albizia spp. because of the people’s attitude towards earning more money through timber production. However, Swietenia mahagoni, Albizia saman, Delonix regia, and Tectona grandis have been domesticated and have a long heritage of introduction.
3.2. Species Family Composition
Araceae, Mimosaceae, and Verbenaceae families represented the highest numbers of four species followed by Caesalpiniaceae, Euphorbiaceae, Poaceae, and Rutaceae representing three species. Amaranthaceae, Asteraceae, Anacardiaceae, Combretaceae, Meliaceae, Myrtaceae, Oxalidaceae, Solanaceae, and Zingiberaceae denoted two species, and the rest of the families comprised only one species (Table 3). Among them, 20 families (55.56%) represented only one species followed by two species were represented by nine families (25%); three and more than three species are represented by four families (11.11%) and 3 species (8.33%), respectively. The family importance value (FIV) was recorded highest for Araceae (163 individuals, FIV 13.4) followed by Mimosaceae (143 individuals, FIV 12.6), Verbenaceae (118 individuals, FIV 11.6), Rutaceae (117 individuals, FIV 9.82) Poaceae (99 individuals, FIV 9.1), Caesalpiniaceae (96 individuals, FIV 8.98), Zingiberaceae (137 individuals, FIV 8.89) and lowest for Lauraceae (11 individuals, FIV 2.16), followed by Urtiaceae (17 individuals, FIV 2.40), Apocynaceae (20 individuals, FIV 2.52), Annonaceae (25 individuals, FIV 2.72), and Acanthaceae (28 individuals, FIV 2.84).
3.3. Ecological Diversity Indices of Homestead Species
The result of Shannon-Winner diversity index value was calculated highest for rural homestead garden both of tree (3.39) and of shrub (2.36) species where for herb species, the highest value (2.5) was found for the urban homestead garden. Shannon’s maximum diversity index value (3.5) was observed highest for rural homestead tree species. In case of herb (2.56) and shrub (2.48) species, the values were similar for both types of the gardens. Shannon’s equitability index (0.97), Simpson’s index (0.04), and dominance of Simpson’s index (0.96) values were found similar for both the rural and urban homestead tree species. For herb species, Shannon’s equitability index value was highest for urban gardens (0.97) where dominance of Simpson’s index (0.91) was found similar for both rural and urban gardens. However, in case of shrub species, Shannon’s equitability index value was highest for rural gardens (0.95); Simpson’s index value (0.93) for urban gardens; and dominance of Simpson’s index value (0.89) for rural gardens. However, in case of tree and herb species, species evenness index value was highest (2.24) for urban homestead garden where for shrub the value (2.19) was highest in rural homestead. Species richness index values for tree (4.98) and herb (2.26) species were highest in rural homestead but for shrub species, the value (2.14) was highest in urban homestead (Table 4).
3.4. Spatial Arrangement of Homestead Garden Species
In the study area, it was observed that homestead gardeners do not follow any specific spatial arrangement pattern and scientific considerations for raising plants. Plants were usually planted in the front, back, and surroundings of the houses. Results revealed that 47.5% of rural gardeners preferred mostly the front yard for species plantation followed by back yard 32.5%, homestead boundary (adjacent to the dwelling house) by 12.5% and 7.5% household owners preferred both pond banks and road side simultaneously. In case of urban area, 35% gardeners preferred balcony and veranda for planting species followed by 30% in front yard, 22.5% in homestead boundary, and 12.5% in rooftop. The reason for this variation was that rural people depend more on homestead forest for their livelihood security as well as certain amount of family income than that of urban households. Except these other factors, those influence the species planting in different sites are beautification of household area, low canopy coverage, land scarcity, and so forth. Ornamental plants, for example, Gomphrena globosa, Tagetes erecta, Codiaeum variegatum, Ocimum sanctum and Nyctanthes arbortristis and major fruit crop species, for example, Mangifera indica, Artocarpus heterophyllus, Citrus limon, Psidium guajava, Zizyphus mauritiana, Citrus grandis, and Carica papaya were usually planted in the front yard of the house (rural and urban) so that the gardeners can keep eye on them. Trees in the homestead-boundary acted as a live fence and windbreak. Tall woody species such as are planted in the back yard for building materials and firewood.
3.5. Choice of Species Grown for Different Usages
The reasons for growing a variety of fruit species in the homestead gardens are more or less complex. A number of factors determined the farmers’ decisions for growing particular species or groups of species. The farmers were keen to grow timber trees for cash income if they already had a successful strategy for deriving income from off-farm labour or from crops. Farmers with large families tend to grow fruit trees. In the surveyed area, homestead plant species generally used for fruit and food, medicines, firewood, timber, and ornamental and beautification purposes were identified. Among them, 45% were fruit and food providing species, 38.71% medicinal plant species, 32.26% firewood species, 29.03% timber species, 16.13% ornamental, beautification, and spiritual species, 11.29% species are used as both for fodder and fence, and 4.83% species used as spice and vegetables.
3.6. Cultural Practices of Homestead Garden
Farmers generally collect planting materials from homesteads wildings (species that are grown/collected from outside homestead premises), friends and families, relatives, government, and NGO nurseries. No specific spacing is followed in planting of species in homestead garden. Sometimes it was also found to plant herbaceous species like Zingiber officinale, Curcuma longa under the layer of shrub like Carica papaya, Citrus limon, and so forth in order to make the optimum use of their land. Study figured out the analysis of respondents answers regarding different aspects of the existing management systems of homestead gardens in the study area. During survey, it was found that some households are not engaged in any management/cultural operations in their homestead gardens whereas other households are more or less engaged with the management of homestead gardens. Species were planted usually during the morning and/or afternoon of the day mostly in the monsoon season. Generally, fast growing and species having low crown coverage are selected for the plantation. The results revealed that almost all the households carried out watering (100%) and soil ploughing (94%). Weeding was done out by 85% of respondents as well as fencing (53.75%) and 67.5% respondents did mulching. Consequently about 62% respondents practice thinning or pruning in their homestead garden. Large farmers generally hired labour for doing thinning and pruning operations. But they do very much little care for manuring (46.25%) and applying pesticide (35%) in their homesteads.
3.7. Role of Homestead Gardens in Local Biodiversity Conservation
Homestead gardens have long been the most effective and widespread measure for biodiversity conservation in Bangladesh as due to anthropogenic pressure and land use change the natural forest has been decreasing day by day both in explicit and implicit ways leading to threats to future productivity. Generally, rural communities preferred cultivated and planted multipurpose species that can be served as fruits, vegetables and spices also used as timber. Such kind of choice is the most important factor to homestead gardens conservation in Bangladesh and plays a significant role in forest conservation since all the wood and other non-timber forest products that are harvested in the homestead gardens do not need to be collected from forests. Respondents said that homestead gardens attract a number of bird species like Streptopelia chinensis, Psittacula krameri, Eudynamys scolopaceus, Micropternus brachyurus, Dinopium benghalense, Oriolus xanthornus, Dicrurus macrocercus, Acridotheres tristis, Corvus splendens, Turdus cafer, Orthotomus sutorius, Copsychus saularis, Nectarinia zeylonica, Anthus campestris, Passer domesticus, and Ploceus philippinus to collect their food and making nest. Moreover, some animal species like squirrel, take shelter and collect their food, especially fruit like Aegle marmelos, Annona squamosa, Areca catechu, Averrhoa carambola, Carica papaya, Carissa carandas, Cocos nucifera, Dillenia indica, Elaeocarpus floribundus, Mangifera indica, Phyllanthus acidus, Phyllanthus emblica, Psidium guajava, Spondias pinnata, Syzygium cumini, Tamarindus indica and Zizyphus mauritiana from the urban and rural homestead gardens. They also mentioned that some birds play a significant role as pollinators or in the control of insect pests. At this time dispersal of seeds, also occurs by the animal, birds and helps in natural regeneration of homestead plants species since natural regeneration is the most important factor for tree diversity conservation. Study also found a number of bamboo, shrub, herb, and climber species which were largely used by the households; also, they give shelter to animal diversity.
3.8. Perceived Importance for Conservation of Homestead Garden Species
To determine the perceived importance of homestead species conservation, farmers were interviewed using a questionnaire; asked to evaluate the importance of mentioned eight functions of trees. The results are presented in Table 5. Likewise, farmers’ perceived most importance for homestead plant species conservation was related to fruit and food (85%) followed by building materials (78.75%), subsistence family income (73.75%), and source of firewood (68.75%). The surveyed rural area is affected by monsoon flood every year; as a result soil erosion is a serious problem in this region. Therefore, in order to keep houses above the water level, it is mandatory to raise houses at the highest elevations or fill the land by soil in the dry season, especially throughout the floodplain regions. As a consequence, people are usually concerned about the trees role to protect their homestead land against water-induced soil erosion by binding the soil. However, they were not concerned about ecological importance of forest. Yet the majority of the respondents graded the homestead garden as being “less important” as a means of maintaining ecological balance and soil erosion control (37.5%), followed by a source of medicinal plants (35%). So, it seems that there is still a lack of knowledge in these two categories, and institutional and government and NGOs training and learning programs are necessary to facilitate knowledge.
4. Discussion
Analysis of the existing tree composition structure and richness revealed that homestead forest in the study area has moderately high biodiversity and species richness. However, the number of plant species was higher than those found in other homesteads of Bangladesh by Abedin and Quddus [53] cited from Alam and Masum [35] found in Tangail (52 species), Ishurdi (34 species), Jessore (28 species), Patuakhali (20 species), Rajshahi (28 species), and Rangpur (21 species) districts, respectively. Motiur et al. [31] found 60 species in Sylhet Sadar; Motiur et al. [34] found 58 species in Southwest Bangladesh; Kabir and Webb [3] recorded a total of 419 plant species from southwestern Bangladesh. Alam and Masum [35] recorded a total of 101 species and Masum et al. [8] 142 species in an offshore island (Sandwip Island) of Bangladesh. Millat-E-Mustafa [54] identified 92 perennial plant species in one study conducted in different parts of the country.
The traditional production system of homestead garden in the study area is moderate in terms of level of cultural practices for absence of improved management practices and high-quality variety. Farmers depend usually on naturally growing plants on their homestead boundary. Besides, analysis of existing management regime indicated that the growers lack of scientific information, almost all the household owners still followed traditional homestead forest management systems, whereas a little owner adopted modern practices. Increased tree planting in the homesteads and their appropriate management, including intercropping practices, should be the strategy for enhancing tree cover of the homesteads of study area in order to meet basic needs of its people and maintain environmental balance. Homestead gardens are playing a potential role in biodiversity conservation as well as uplifting the socioeconomic condition by contributing families or household’s annual income and providing nutritional diet to families. Variable homestead garden products such as seasonal fruits, firewood, medicinal plants, timber, and vegetables and spices were mostly used by the small and medium household owners for their daily needs but large owners get their products into the market for sale. These findings are also supported by the study of Millat-E-Mustafa [54] for the homestead garden of four regions in Bangladesh. Most of the households were found to prefer mostly food or fruit species (45%) because of the income incentives and family needs, and this was also supported by several researchers [8, 21, 54] across the country.
In the present study, homesteads gardens were largely user oriented, and market access was not fully developed. However, market access for homestead products is essential as, they sell their products easily into the market as well as other forest products. It was shown that most of the producers were selling to their neighbours or local traders. Therefore, they do not get proper price for their products. If they get their products to the market or sell products via retailers, they will get proper prices also, which is very much important for the small household owners, therefore creating a scope for income. Many studies of tropical homestead garden have reported reduced species diversity and stem density in homestead garden with closer proximity to market for example [55]. So, market access condition has great effect on homestead forest management; thus, further study is needed to directly test the influence of market access on the homestead gardens structure of both commercial and subsistence-oriented homestead garden in Bangladesh. However, the homestead gardens of the study area present an excellent example of all embracing multipurpose land-use system and biodiversity conservation.
4.1. Species Diversity and Biodiversity Conservation in Traditional Homestead Garden Farming System
Biodiversity conservation has become a growing concern for all over the world, and it is linked up highly with long-term health and vigour of the biosphere, as an indicator of global environment and also as a regulator of ecosystem functioning [56]. The biological diversity indices revealed that homestead garden could play an important role for carbon sequestration in the future since plant growth is directly proportional to the carbon sequestration capacity of the forest [57, 58]. By studying different literatures of homestead gardens all over Bangladesh, we have developed in our mind that a number of opportunities and drawbacks are influencing the selection of species of homestead garden. Considering all these, we have developed a model of species diversity and biodiversity conservation for both urban and rural surveyed homestead gardens represented in Figure 1. We classified the opportunities and drawbacks of a typical homestead garden for both rural and urban areas separately. Among the opportunities, the most prominent according to our observation were generating income, food security, soil erosion control, timber demand, market access, beautification, cattle fodder, medicinal purposes, and fuel wood species. The drawbacks that are influencing the selection of species were cropland expansion, fast growing species demand, natural calamities, land scarcity, domestic animal, low crown canopy, infrastructure, and so forth. The economical condition of the rural people is not as like as urban people. For this, they usually prefer species that will provide them necessary fuel wood and fodder for their cattle. Plantation of medicinal plant species can help to get remedy from diseases; also regular supply of raw materials to the industry could be an important source of earning money to the farmers. Urban people usually prefer to plant various flowering and ornamental plants such as Tagetes erecta, Gomphrena globosa, and Codiaeum variegatum for ornamental beauty of their houses because they occupy a smaller space in their garden premises, and they do not like such condition that will decrease the beautification view of their house. The trend in gradual replacement of functional plants to ornamentals has also been observed in cases where people became richer [59]. Side-by-side grazing of domestic animals disturbs the diversity of homestead forest species. In this circumstance, introduction of grasses, sedges, and small bushes could be a solution to get remedy to this problem. This type of management could help villagers in getting fuel wood without disturbing the main vegetation. Whatsoever, it is now clear that homestead garden is a storehouse of large species diversity and sustainable resource management, and this large species diversity can play an important role in biodiversity conservation.
5. Conclusion
For aesthetic, environmental, and economic perspectives, species planting in homestead garden is desirable. Homestead gardening plays a significant role in both rural and urban landscape planning and management. In this study, we have observed that the homestead plant composition, diversity, and species richness were moderate in Kishoregang Sadar area. Moreover, there was a lack of scientific knowledge of the gardeners, an absence of proper planning, and no specific objectives and goals. Present study did not discuss any economic contribution and market access for homestead; thus, further study is highly recommended and needed to directly test the economic significance and influence of market access on the vegetation structure of both commercial and subsistence-oriented homestead gardens in northern Bangladesh. The moderate domination of fruit species over timber species may be attributed to the gardeners’ general perception that fruit species would bring early return as well as the multipurpose nature of fruit species. Homestead garden could provide employment opportunities for both male and female members, resulting in increased family income for better livelihood to a large population in northern Bangladesh. Till now, there is no specific management plan of homestead gardens all over the country although it has tremendous contribution to greening the nature. Considering the present state of the homestead garden of the study area, this paper suggests that there is a need to establish proper planning and management mechanisms from government for homestead garden. This can be done by providing some incentives and/or training to the owners to be more careful about conserving garden species to improve both rural and urban plant species coverage. It is also recommended that experimentation with new and diversified tree species can play an important role in enhancing the diversity and distribution of homestead garden in the Kishoreganj Sadar area.
Acknowledgments
The authors are highly grateful to each and every respondent who participated in this study for giving their valuable time and information regarding their homestead gardens. They are very much grateful to Mr. Avik Kumar Roy for his consistence support during data collection as well as for giving overall idea about the study area.