BEE FLORAL CALENDAR OF CULTIVATED AND WILD PLANTS AVAILABLE IN DIFFERENT AGROECOSYTEMS OF CHITWAN, NEPAL

Beekeeping is one of the promising enterprises for economically poor farmers in Nepal but beekeeping farmers lack flora calendar for pollination, bee foraging, and honey production. Therefore, a study was conducted visiting farmers’ fields every 15-20 days during 2012-2013 to monitor the common plant species visited by bees, which were considered as bee forage plants categorized as major, and minor sources of pollen and/or nectar. Relevant information was also gathered through key informant interviews and group discussions. During the study period a total of 252 plant species were recorded and their floral calendar prepared. In the study area. The main species identified were: rice, Oryza sativa L.; maize, Zea mays L.; buckwheat, Fagopyrum esculentum Moench.; rapeseed, Brassica campestris L.; sesame, Sesamum orientale L.; litchi, Litchi chinensis Sonner; and cucurbits (bottle gourd, Lagenaria siceraria (Molina) Standl; sponge gourd, Luffa cylindrica (L.) Roem.; bitter gourd, Momordica charantia L.), Leucas (gumpate), Leucas lanata Benth.; Butternut (chiuri), Bassia butyracea Roxb.; Pogostemon (rudilo), Pogostemon glaber Benth.; guava, Pisum sativum L; Sisoo, Dalbergia sissoo Roxb.; Throughwort (Banmara), Eupatorium sp.; silk tree (Padke), Albizia julibrissin Durazz ; Terminalia (Saj) Terminalia bellirica (Geartn.) Roxb. and Murraya (kadipatta) Murraya koenigii (L.) Spreng. Species of Brassica, Pogestemon, Bassia, Citrus, and Artemisia, Pisum, Ipomoea and Eupatorium species were some of the important plants which bloomed during winter. And, Lagerstroemia sp., Impatiens sp, Sesamum indicum L., Zea mays L., Albizia sp. and many cucurbits bloomed during rainy season. Fagopyrum esculentum Moench, Brassica campestral L, Lagerstroemia indica L, Bombax ceiba L, Albizia julibrissin Durazz., Eugenia formosa Wall., Shorea robusta, Guartn. Upatorium grandulosum, Pogostemon glaber Benth. Terminalia alata Heyne ex.Roth, Murraya koenigii (L.) Spreng Sesamum orientale L. Dalbergia sissoo Roxb. were the major bee flora both rich in nectar and pollen.


Introduction
Nepal is rich in plant and insect diversities. The wide diversities of crops and other plants benefit from pollination services of insects particularly bees, which result in one-third of the total human diet with pollination value worth of 143 times higher than honey production in the world (Mishra, 1997/98). The value of insect pollination for worldwide agricultural production is estimated at 153 billion, which represents 9.5% of the value of the world agricultural production used for human food in 2005 (Gallai et al., 2009). The average global value of pollination system is $ 117 ha -1 yr -1 (Costanza et al., 1997). Crop pollination yield with enhanced quality in entomophilous orchard fruit crops (Garratt et al., 2013), in field crops (Bommarco, 2012), and small fruits and vegetables (Andersson, 2012;Roselino et al., 2009;Hogendoorn et al., 2014;Roldan, 2006;Isaacs, 2010). Some crops entirely depend on insect pollination for seed and fruit production, whereas others benefit with higher yields, better quality produce and uniform maturation (Breeze et al., 2011).
Chitwan district lies in the southern part of Narayani zone in central Nepal. This district enjoys a sub-tropical climate with a unique ecosystem of significant value to the world (i.e. Chitwan National Park). Approximately, 70% of the National Park vegetation is sal (Shorea robusta) forest, grassland (20%), riverine forest (7%), and sal with Chirpine (3%). The riverine forests consist mainly of khair (Acacia catechu (L.f.) Wilid. sissoo (Dalbergia sissoo Roxb.) and simal (Bombax ceiba Lin.). The grassland forms a diverse and complex community with over 50 species (Dangol, 2000). This district is well acquainted as granary of Nepal. However, high pressure of migrant from different district of Nepal in Chitwan resulted in negative impact, i.e. change in biodiversity and vegetation composition (Dangol, 2000). Declining of pollinators has been noticed by different researchers (Pokhrel 2005 Wilson (1988) estimated that 0.2-0.3% of all species are lost every year in globe. Range of 5-10% of the tropical forest species may become extinct within the next 30 years (UNEP, 1993). In the district, there are no in-depth records of bee flora in pollination and beekeeping perspectives, which have long lasting effect on the livelihood of the people living in the area.
To maintain diversity of flora, self-incompatible and cross-pollinated crops require efficient pollination services of honeybees and other pollinators, and also self-pollinated crops benefit from insect by showing their hybrid vigor without any desertion in their innate properties of fruits and seeds (Thapa, 2006). The flowering plants of an area having good value as bee pasture are necessary to maintain bee colonies (Baptist and Punchihewa, 1980). Hence, every beekeeper must be familiar with the bee floral resources near/ or around his/her apiary for successful beekeeping and also bee fauna greatly influence crop pollination and reward hive production.
All pollinator species do not respond equally to land use change (Williams et al., 2010;Winfree et al., 2011). The flowering crop field has been known as an important driver for pollinator community composition, and the landscape context needs to be considered when linking land use Http://www.granthaalayah.com ©International Journal of Research -GRANTHAALAYAH [224] to pollination provisioning and benefits to field crops (Bartomeus et al., 2014). Delaplane et al.
(2010) revealed that in planning a bee pasture, it is important to choose a collection of plants that will produce unbroken succession of bloom throughout the season. Furthermore, seasonal changes in the vegetation patterns, the foraging behavior of bees, and the manner in which the honeybee colonies interact with their floral environment are the major events which determine the best time to carry out bee husbandry practice or prepare for the honey seasons and food shortage periods with feeding management as well. Different studies (Partap and Partap, 2002;Thapa, 2002, Adhikari andRanabhat, 2003) reveal that level of knowledge about biodiversity conservation, pollination and pollinators in Nepalese farmers are inadequate. Hence, this study was carried out to identify the common bee flora in the study areas, estimate their seasonal abundance and diversity, prepare flowering calendar and identify the nectar and/or pollen producing sources for potential beekeeping by the farmers.  (Partap, 1997). For scaling up beekeeping, the area of agricultural bee forage (in hectare) and potential foraging bee colonies with minimum of two hives per hectare were estimated as potentiality of bee forage supporting honeybee colonies in those areas . Honey potential is the estimated weight (kg) of honey that can be obtained in the course of a season from one hectare of land covered with the plant assuming optimal condition (Crane, 1975), which varies from species to species and also according to climatic and soil condition (Partap, 1997).

Study Area
Key informant interview and focus group discussion were also organized once in each study area purposively selecting the communities, such as pollination farmer groups, local leaders, buffer zone technicians, bee technician, and other individuals, who are believed to be knowledgeable about bee flora of the study sites. The secondary data included the existing research literature. Related websites of GOs and INGOs, such as, ICIMOD, IAAS, AFU, CBS, CABI, IUCN, and ISSG etc. were consulted to review literature on biological characteristics of the plants. Data were managed in Microsoft Excel and analyzed using descriptive statistics for frequency, density, flowering duration etc.

Crops and Wild Plants Distributed in The Study Areas
The  Observation shows that Megauli has the richest bee flora (242 species), Siddhi (222 species), followed by Jutpani (221 species), and Fulbari (190 species), respectively ( Table 2). The bee flora diversity was higher in the Megauli, iddhi and Jutpani VDCs compared to Fulbari VDC (217 species), mainly due to the dominancy of wild flora there. The beekeeping enterprises flourished there because of availability of greater diversity of wild bee forage resources for the honeybees. The bee forage plants available in different months with their sources is shown in Table 2.    1  2  2  0  2  2  1  5  4  3  3  1  Oilseed  2  4  2  2  1  1  3  2  3  2  1  2  Vegetable  4  10  14  13  10  10  7  8  6  6  3  3  Fruits  1  5  16  16  7  4  1  1  1  1  1  1  Ornamental 6  7  7  9  13  15  14  14  12  12 8  8  Wild  22 33  35  45  48  53  48  36  33  25 15  9  Total  39 63  78  85  83  87  75  71  63  52 34  25   Table 3 summaries the crops and wild bee forage with their flowering months, which indicated that majority of bee forage available in Feb-September. Though rainy season is drought period in Chitwan condition, many wild plant species found flowering in the season. Migration of bee colony in different places within Chitwan can lower the feeding to the bees in winter and rainy seasons. Plants identified as bee forage are categorized as source of pollen (P1, P2) or nectar (N1, N2) and their combinations with their status in the study areas of Chitwan (Table 2). This includes 50 plant species rich in both nectar and pollen (N1P1), 14 species N1P2, 8 species N2P1, 74 species N2P2, 18 species rich in pollen only(P10, and 51 species as minor source of pollen (P2), 13 species rich in nectar (N1) and 24 species low nectar( N2). Pollen is necessary for brood development which were found to a greater amount in wild plants compared to crops. However, most of the wild plants which had low content of nectar and pollen.  2  2  1  2  2  2  1  1  0  0  1  1  8  N2P2  22 33  35  45 48  53  48 36  33  25 15  9  74  Total  51 75  89  104 102 104 93 81  73  62 43 28 252 Table 5 shows that bee forage were find well distributed throughout the year, however most of the species got flowering from Feb to September. Less number of plants were got flowering in November-January.

Discussions
Chitwan is rich in bee flora, i.e. 252 bee forage species were found during study. Most of these species were included in plant species lists in several other studies of Dangol and Shivakoti (2001), Thapa (2006) and Pokhrel, (2005) . Many crop and wild plants visited by bees in Chitwan include: litchi, buckwheat, rapeseed, Indian mustard, cowpea, radish, broccoli, sponge gourd, cucumber, brinjal, red gram, okra, mango, citrus, squash, bottlebrush, sesame and bottle gourd as reported by many workers (Thapa, 2002;Dhakal, 2003;Neupane, 2000;Devkota, 2000). The availability of major honey potential flora has led to great scope for beekeeping in the district. This is further supported by the availability of minor flora which mainly consists of wild flora which supports bee even in the dearth periods. This study was concurrence with the floral study of Kavre and Dolakha (Bista and Shivakoti, 2001) and Pokhrel (2005), respectively. Bista and Shivakoti (2001) at Kabre, Dolakha district indicated that the peak periods of honeybee foraging activity and abundant bee floral plants were recorded during mid-February and May (spring season); whereas from mid-November to February (winter season) is dearth period and the colony strength can be weak However, availability of honey potential bee flora is shown comparatively lacking in summer, which was also similar to the study of Mishra (1997Mishra ( /1998. Less honey potential floral sources are available to bees from June to September, so these months are very harsh for bees. Higher numbers of bee flora recorded in Megauli under semi-natural, shrub land and watershed areas found positive impact in biodiversity conservation as indicated by Emiru et al. (2006), in eastern zone of Tigray, Ethiopia. Jacobs et al. (2006) emphasized on bee flora species and other multipurpose species for rehabilitation of degraded and watershed areas, which were seen in Megauli. Akratanakul (1990) also lists guidelines for the exploration and evaluation of potential area for beekeeping with honeybee plants having relatively long blossoming periods, generally in terms of several weeks or months.
Knowledge about bee flora with their flowering time is very crucial for the farmers. Figure 2 shows that cultivated and wild bee forage plants bloomed in different months, however, the potential source of nectar and pollen were found in November to April, known as honey flow seasons in Chitwan condition. Honey flow is primarily due to the sufficiency of bee flora rapeseed, Http://www.granthaalayah.com ©International Journal of Research -GRANTHAALAYAH [243] in small fruits and vegetables (Andersson, Rundlof and Smith, 2012) and Partap C (1997) in fruit and seed production. However, this practice was not followed by the farmers resulting in low crop productivity there. Studies done by Partap and Partap (2002) and Thapa (2002) reveals that level of knowledge about biodiversity conservation, pollination and pollinators in Nepalese farmers are inadequate.

Conclusion and Recommendation
A total of 252 common bee flora species were identified in four study areas of Chitwan. The common bee forage species identified included: rice, maize, buckwheat, cowpea, black gram, rapeseed, mustard, and cucurbits, Lichi, citrus, Eupatorium, Pogostemon, Sissoo, Acacia, Termenalia, Albizia Morraya (kadipatta), Leucas. Most of the important bee flora was blooming from November to March, and this was peak period for honeybee foraging activity as well as peak time of honey harvest. There was shortage of bee forage in winter (Nov -January) and rainy period (June-Aug). There was variation in bee flora species diversity and abundance in different land use system, i.e. somewhat fewer floral species were recorded in organic site, i.e. Fulbari VDC, which was far from natural forests. In the study areas, there was good availability of bee forage in the summer season also. This was one of the positive impact of conservation of National Park, community forests, watershed and fallow lands. Though the sufficient bee flora was available in intensive agriculture practiced area, farmer kept away their hives in other places for foraging due to heavy use of pesticide in their crop fields. Hence, awareness raising program should be organized to educate them about importance of bee flora in pollinators and honey production. However, in the dry season only few bee flora plants were in bloom and this affected the colony performance. Therefore, to solve this problem beekeeping based agro-forestry practices on cultivated land, and selection of plant species that can tolerate drought and set flower for a long period should be introduced. Introduction of similar major honey producing plants in other countries or regions with similar vegetation patterns, agro-ecosystems, climate, and edaphic conditions also seemed necessary. Emphasis must be given honey potential plant which blooms longer period rather than covering large area. The large-scale planting of honeybee forages should be integrated with other agricultural activities, such as reforestation, roadside plantings, and animal pasture.