Home Gardens in Nepal

were taken and consulted with the taxonomist from Institute of Agriculture and Animal
Sciences (IAAS). Therefore, the identification of species is based on the morpho-
physiological and taxonomic studies. The current study lacks a molecular study to verify the
species diversity due to time and financial limitations.

Data analysis

SPSS for windows version 10.1 was used to produce descriptive statistics of survey data.
Shannon-Weaver Index was used to determine the species richness. The index is used to

characterise the species diversity in community. It is calculated using the formula H ́= -∑

=

s

i 1

pi

ln pi, where s is the number of species in the community and pi is the proportional abundance
of species i (= number of species i divided by total numbers in the community). The term pi
In pi is calculated and summed for each species in the community. With this index diversity
increases as: species become more evenly distributed in abundance and more species are
added to the community. The maximum value that the SWI can reach depends on the
number of species in the community (maximum H’= In s) Evenness index (J= H ́/In s) was
used to describe the diversity in terms of evenness i.e. how equally abundant the species
were in the home gardens. This standardizes evenness on a scale from 0 to 1. Also,

Simpson’s index (λ= ∑

=

s

i 1

(pi)^2 was used to describe the dominance i.e. the degree that a

community is dominated by one or a few common species. The index measures dominance
on a 0 to 1 scale. If only one species is present in the community, Pi= λ =1 will be the
maximum value. Mann-Whitney U-test was carried out to see the difference in species
richness in two ecologies using MINITAB version 13.31.

RESULTS AND DISCUSSIONS

Crop species diversity

A total of 165 different crop species with a mean of 30.77±11.9 from 55 plant families were
recorded in 134 home gardens from two agroecological study sites. The Terai had a total of
123 crop species (27.1±10.7) whereas 131 species (38.7±10.5) were recorded in the mid-
hill. The species numbers was significantly (p=0.001) higher in Gulmi mid-hill than the
Rupandehi terai ecology. Within Terai ecology, the total species of Baikunthapur (116
species) was significantly higher (p=0.001) than that of Bharsa (92 species). SWI in the mid-
hill was higher (H’ = 4.41) than in the terai (H’ = 4.25). It indicated that the species richness
of home gardens in Gulmi Mid-hill is higher than that of the terai (Table 2).The dominance
measured by Simpson’s Index explained the terai ecology (λ = 0.018) home gardens had a
relatively stronger dominance of a few species as compared to the mid-hill (λ = 0.014). The
Evenness Index revealed the species in the Mid-hill (J = 0.906) were more equally abundant
and evenly distributed as compared to the terai ecology (J = 0.880) (Table 2).

Table 2. Shannon-Weaver, Simpson’s and Evenness indices estimated for species diversity in
Terai and mid-hill ecology, 2003.
Ecology Study sites Shannon –Weaver
Index (H’)

Simpson’s

Index (λ)

Evenness

index (J)

Terai Bharsa 4.03 0.022 0.891