Study area

   The study was conducted in Kumaun Himalaya in Uttarakhand State of India. The study sites were selected in Nainital district between 300-2000 m above mean sea level (29^o19’-29^o28’ N and 79^o22’-79^o38’ E). Four sites were selected along an altitudinal gradient viz., very low altitude (up to 350 m), low altitude (350-700 m), mid altitude (700-1500 m) and high altitude (above 2000 m) (Figure S1, Appendix A ). At each altitude, homegardens were categorized into three size classes viz., large (above 0.007 ha), medium (0.004-0.006 ha) and small homegardens (up to 0.003 ha) and three replicates for each size class at each altitude were selected. Climatically the study area falls within sub-tropical to temperate zones.

Sampling Method

   We have selected thirty-six homegardens from four altitudes (three homegardens of each size) on the basis of stratified random sampling. For phytosociology analysis, quadrat method was used and random quadrats of 10m × 10m size were laid for trees, 5m × 5m quadrat for shrubs and 1m × 1m quadrats for herbs in the selected sites (Curtis & Mcintosh, 1950). Plant species were identified with the help of vernacular name, flora, some relevant literatures and research papers (Gupta, 1968; Pande, Vibhuti, Awasthi, Bargali, & Bargali, 2016; Samant & Palni, 2000). Information regarding use of plants was collected through semi- structured questionnaire/interview from homegarden owners (Supplementary file 1, Appendix A ). Utilization of the plant species were categoried on the basis of their primary uses.

Family Importance Value (FIV Index)

   Family Importance Value (FIV) index is combination of richness, density and dominance. The FIV index was used to estimate the floristic composition at the species family level (Mori, Boom, Carvalino, & Santos, 1983).

Relative prevalence (RP)

   Relative prevalence (RP) of plant species was calculated following Zaman, Siddiquee, and Katoh (2010) as:

Relative prevalence (RP) = ni/A × fi/F

Where, ni = Number of specimen species i in homegarden, A = Area of homegarden, fi = Number of homegardens in which species i is present, F = Total number of homegardens.

Statistical Analysis

   Data and samples were collected from study sites. The data was complied with help Microsoft Excel and for statistical treatment using the STATISTICA and SPSS software to prove the statistical significance of the results obtained.

Figure 1

Average species richness in homegardens of Kumaun Himalaya.

Species composition and family importance value

A total number of 57 plant species belonging to 27 families were recorded. The homegardens of mid altitude (MA) supported maximum number of plant species (39) of which, medium sized homegardens (MHGs) shared 27 plant species followed by the large (25) and small (19) sized homegardens (LHGs, SHGs). At this altitude, 11 and 7 species present exclusively in MHGs and LHGs, respectively while 21 species were common in all sized homegardens (Figure 1). The high altitude homegardens (HA) supported lowest number of species (24 sp.) of which, LHGs contributed maximum (18 sp.) followed by MHGs (15 sp.) and SHGs (11 sp.). At this altitude, 1, 3 and 7 species were reported exclusively in SHGs, MHGs and LHGs, respectively while 13 species were common in all sized homegardens (Figure 1). The family importance value was recorded highest for family Amaryllidaceae (FIV=55.12). This family represented maximum number of species in all sized homegardens at all the altitudes followed by family Caryophyllaceae (FIV=27.71) in LHGs at low altitude (LA) and family Asteraceae (FIV =24.07) in LHGs at high altitude.

Figure 2

Plant utilization pattern of homegardens at very low(a), low (b), mid (c) and high

altitude (d).

Family Ebenaceae recorded lowest family importance value (FIV=3.97) in MHGs at mid altitude (Table 1).

Utilization pattern of homegardens species and their relative prevalence

There were six different utilization categories on the basis of primary important needs viz fruit, vegetable, spice, medicinal, fodder and other miscellaneous product (oil yielding, building purpose materials and religious values). Plants of medicinal and edible (vegetables) categories were the most frequent component followed by fodder, fruits, spices and miscellaneous categories in different sized homegardens (Figure 2). At very low altitude, medicinal plant contributed maximum in MHGs while vegetable was maximum in SHGs. At low altitude, contribution of medicine and vegetable was higher in MHGs. At mid and high altitudes, contribution of medicine was maximum in SHGs while vegetables contributed maximum in MHGs (Figure 2).

Figure 3

Plant part used in homegardens at different altitudes.

(SHGs,MHGs, LHGs=small, medium, large homegardens, VLA, LA, MA, HA= very low, low, mid,

high altitude)

Fruit species cultivation was highest in LHGs at high altitude (22.22 %) whereas least fruit species cultivation (6.67) was recorded in SHGs at very low altitude. In an average percentage of plant species were used as spices, in which maximum contribution was recorded in SHGs at mid altitude (14.29 %) and minimum contribution was observed in LHGs at very low altitude (6.67 %). Among the different spice crops, C. sativum, C. longa and C. annuum were frequently cultivated species. Other miscellaneous plant species like C. dactylon, O. sanctum and M. indica were considered important religious plants and used in various rituals (Figure 2).

Relative prevalence provides the importance of individual species in a particular area. Among the cultivated herbs, A. cepa was the most prevalent species in SHGs at mid altitude (RP=4666) whereas A. esculentus, A. sativum, C. sativum and P. sativum showed least relative prevalence value in LHGs at mid altitude (Table 2). For wild herb species, relative prevalence was maximally shared by A. conyzoides in MHGs and minimum (RP=1800) by V. serpens (RP=277) in LHGs at mid attitude. For cultivated trees species, C. sinensis was most prevalent (RP=1200) in MHGs while C. limon and M. indica were the least prevalent species in LHGs at mid altitude (RP=277) (Table 2). Mid altitudes showed the most relative prevalence with a most utilizable species (Table 3). In the homestead homegarden, leaves were used in maximum by household member for own consumption followed by fruits,root, rhizomes, twig, stem, and seed at all the altitudes (Figure 3).

Status of homegardens plant species

According toSenanayake, Sangakkara, Pushpakumara, and Stamp (2009) species richness is influenced by homegarden size, managed by owners to fulfill their regular needs and for this they grow multipurpose plant species utilized for the different purposes.Yirefu, Adugna, and Behailu (2019) stated that utilization of homegarden product and their management can secure food productivity which determined by environmental factors and dietary habits as well as the socio-economic and market demands. In this study, the species richness showed significant positive correlation with homegarden size (Figure 4) at all the altitudes except mid altitude. In contrast, homegardens of Mexico (Rico-Gray, Garcia-Franco, Alexandra, Armando, & Paulino, 1990) and Indonesia (Abdoellah, Hadikusumah, Takeuchi, Okubo, & Parikesit, 2006) the numbers of species or individuals were not related to homegarden size. In the present study the mean species richness per homegarden ranged from 11 to 27.Martin, Geiger, Singhakumara, and Ashton (2019) estimates 64 species/garden in the Southwest region of Sri Lanka andKebebew (2018) observed 10 to 45 species in Arba Minch town, Southern Ethiopia. Across the homegarden sizes, species richness increased with increasing homegarden size except mid altitude homegardens where species richness was maximum in medium sized homegardens similar to the findings of Das et al. (2005). Family Importance Value indicated that across the altitudinal gradient, Amaryllidaceae was the most important family followed by Oxalidaceae (Table 1). These variabilities may be due to the changes in the procedure, plant life forms, topography and ecological factor.

Figure 4

Regression equation showing relationship between species richness and homegardensize at different altitudes.

Plant utilization pattern

In the study area, homegarden species are used for primary and secondary needs of the family members and utilized as fruit, vegetable, medicine, timber, fuelwood, ornamental plant, sacred purposes and other miscellaneous purposes (Figure 5). Albuquerque et al. (2005)Albuquerque, Andrade, and Caballero (2005) reported the predominance of medicinal plants (26%) in homegardens of North-Eastern Brazil.Cui, Fu, Guo, and Chen (2000) also recorded that species of plants in traditional homegardens of China were utilized as: medicines (23%), vegetables (21%), fruits (19%), ornamentals (9%) and spices (7%). Dash & Misra (2001)Dash and Misra (2001) also observed that the vegetables and spices are the most edible cultivated plant in homegardens of Eastern Ghats of Orissa. WhereasSunwar, Thornstrom, Subedi, and Bystrom (2006) reported vegetable and species are the most important utilising products in Nepalese homegardens. (Blanckaerta, Swennenb, Floresa, Lopez, & Saadea, 2004) recorded 65.7 % ornamental, 29.6 % edible and 8.6 % medicinal plants in the homegardens of Mexico. These findings indicated that plant diversity was selected for cultivation in homegardens according to the requirements of the household. In our study, homegarden have a complex plant diversity from herbs to trees. The production of cultivated crops was consumed by family member and the local communities. The community also prefers the wild plants, fodder, wood and other miscellaneous uses from the homegarden system in small amount which is enough to them (Shukla, Kumari, & Chakravarty, 2017; Vibhuti, Shahi, Bargali, & Bargali, 2019).

Figure 5

Percent utilization of different use categories of homegarden species.

Relative Prevalence of homegardens species

Percentage of homegarden comprising with a particular species, represents relative prevalence of that particular species in area. Cluster of homegarden species across the altitudinal gradient on the basis of their relative prevalence is presented in Figure 6. Among the species, A. cepa (1380) and C. annuum (1026) showed most prevalence whereas S. cumini (278) was the least prevalent species. Across the altitudinal gradient, mid altitude showed most (2341, 1330) relative prevalence whereas high altitude showed least (876, 0) relative prevalence for A. cepa and M. indica, respectively Table 3. Uddin et al. (2002), reported red amaranth (RP=11690) and Indian spinach (RP=4606) as the most prevalent species in the homestead of Southeastern Bangladesh. The homegarden supply food especially for farmers in the rural areas because it could be maintained with low-cost input and diversified with high output.

Figure 6

Cluster of homegarden species across the altitudinal gradient on the basis of their relative prevalence.

In this study, traditional homegardens of all villages possessed a multilayered vegetation structure. M. indica, L. chinensis, C. papaya and F. auriculata were the most frequent and dominant trees in very low and low altitudes, Citrus sp., D. kaki and G. optiva trees were most common in mid altitude whereas in high altitude, P. persica, P. armeniaca and M. domestica were most dominant trees. Herb Plants like A. cepa, A. sativum, C. sativum, C. maxima, L. siceraria, A. esculentus and C. esculenta were cultivated as vegetable plants in majority of homegardens at all the altitudes. Medicinal plants have a various therapeutic properties were abundant in all household homegardens. Most wild species like O. corniculata, S. media, C. dactylon, A. conyzoides and G. parviflora were used as fodder in different altitudes. The presence of fodder trees and grasses has a crucial value, which resulted in increase in the number of livestock and decrease in the livestock forage cost and women drudgery.