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Introduction

The land use pattern is one of the important aspects for analyzing the structure, composition and phyto diversity for understanding the vegetation dynamics of the existing sites. The farmers have adopted the trend of growing trees around agricultural land due to significant economics as well as social benefits. But it will be worthwhile to work out an integrated approach with the help of agricultural and forestry scientists, depending on the suitability of crops and locations.¹⁵New land-use strategies that increase livelihood security and reduce vulnerability to climate and environmental change are necessary.¹³Community structure, composition and vegetative function are the most important ecological attributes of forests, which show variations in response to environmental as well as anthropogenic activities.^7,19Species diversity is an important concept and one of the major attributes of a natural community. These differences in vegetation structure, richness, diversity and distribution are directly associated with the intensity of variables like geographical location, agricultural practices and their extent.⁶In Central and Eastern Uttar Pradesh, the agroforestry systems are well established. As multiple cropping is a kind of natural resource management based on environmental, social and economic criteria which is done by combination of trees, pasture and cropland, in order to increase social, economic and environmental benefits. Tree plantation and harvesting of wood, fruits, roots, leaves, fuel, and fodder along with agricultural crops on the same piece of land has been practiced since the old days. However, under present scenario, the agroforestry techniques used by the farmers seems to be poorly developed and exploitative. In most cases, the trees are neither protected nor properly managed. Hence, there is an immense potential tool for improvement of traditional agroforestry systems in order to realize the real production potential of existing agroforestry systems. Greater agrobiodiversity also may ensure longer term stability of C storage in fluctuating environments,⁸apart from the biomass production potential.¹⁰

Main aimed of this paper are to describe the structural attributes of density, frequency, diversity, equitability and species richness on the existing agroforestry systems in Fatehpur and Allahabad districts of Uttar Pradesh. This helps in determination of predominating communities of timber trees, horticultural trees and shrubs species and further identify the localities having protection and promotion of these plants.

Material and Methods

植物区系组成和结构的研究xisting agroforestry systems was carried out in the farmer’s fields of village Dariyapur (Site-I) and Alampur (Site-II) at Fatehpur district (Uttar Pradesh) during 2008-2010. The research area is located between two important river Ganga and Yamuna. The study illustrated that status of density, frequency, Abundance, IVI, Species –diversity, concentration of dominance, species-richness, Equitability and Beta diversity and other useful parameters for comparison of different types of existing agroforestry systems were analyzed by the simple arithmetic calculation. The quantitative characteristics of vegetation were determined by the quadrat method. The floristic diversity study was made by adopting random sampling approach, under which, 20 quadrates of 10 m x 10 m and 5 m x 5 m size were laid out in each sites for the observation of trees and shrubs respectively. The vegetative structure of trees and shrub in each two sites was estimated for frequency; density and abundance by using expressions given by Curtis and Mc Intosh, 1950.⁵Floristic diversity studies of the herbaceous species were not attempted.

Basal area of trees was calculated as cross sectional area of stem at DBH (1.37 m), while basal area of shrubs was calculated as cross sectional area of main stem at 15 cm above from the ground level.

Basal Area = π(d²/4)

The relative density, relative frequency, relative basal areas were calculated using following formula.

The importance value index (IVI) is an integrated measure of the relative frequency, relative density and relative basal area/dominance, was calculated for each tree species given by Curtis, 1959.⁴

Importance Value Index (IVI) = RD+RF+RBA

The number of trees falling in the sample unit was counted and classified as per their diameter and height. The Species diversity (Shannon index), concentration of dominance (Simpson index) and other useful parameters for comparison of different types of existing agroforestry systems were calculated.^17,18

Tree Diversity Analysis

Tree diversity in all two sites of agroforestry systems (trees and shrubs) were calculated by the following diversity indices.

Species Diversity Index

It was calculated by the formula given by Margalef, 1958.¹²

H = -∑ [(ni/N) log (ni/N)]

Where ni was the total number of individuals of species N was the total number of individuals of all the species on that site.

Concentration of Dominance

was measured by the formula of Simpson Index developed by Simpson, 1949.¹⁸

Where N was the total number of individuals of species ni was the total number of individuals of all the species on that site.

Equitability(e)

was calculated as suggested by Pielou (1975)¹⁴as

e = H / In s

Where H is the Shannon – Wiener Index and s = total number of species

Species richness

was calculated by the following equation of Margalef (1958)¹²

d = s- 1/In N

Where s = number of species, and N =number of individuals of all species

Beta diversity

was calculated as outlined by Whittaker, 1977.²¹

bd = Sc / s

Where Sc = total number of species in all sites and‘s’ is average species per site.

Results and Discussion

Floristic-diversity analysis and distribution patterns of tree species

The distribution patterns and species composition of existing agroforestry systems viz. agrisilvicultural and agrihorticultural system commonly practiced in Fatehpur was studied.

Floristic- diversity at site–I (Dariyapur) of Fatehpur:

The data pertaining to floristic diversity analysis presented in Table: 1 and graphically illustrated in Figure: 1, shows that dominant and co-dominant species wereAcacia niloticaandAzadirachta indicahaving IVI values of 22.04 and 20.31, respectively. The highest tree density (60 trees ha^-1) was also recorded forAcacia nilotica．在园艺和年代hrubs species, dominant and co- dominant species wereMangifera indicaandEmblica officinaliswith their IVI values of 19.23 and 14.02, respectively. The highest tree density (50 trees/ha) was recorded forEmblica officinalis．Total basal cover was recorded markedly higher (5.69 m²/ha) inFicus religiosaas compared to Madhucalatifolia (5.10 m²/ha). In horticultural and shrub species the basal cover was recorded maximum in case ofMangifera indica(4.99 m²/ha) andEmblica officinalis(0.69 m²/ha).The similar results were also reported by Rawat and Chandhok (2009).¹⁶Among tree species, total forest density ranged from 470 to 600 trees ha^-1．

Floristic- diversity at site –II (Alampur) of Fatehpur

Floristic- diversity analysis data of site-II are presented in Table: 2 and graphically illustrated in Figure: 2, shows that the dominant and co-dominant species wereAcacia niloticaandMadhuca latifoliahaving their values of IVI 24.91 and 23.95, respectively.Acacia niloticashowed highest tree density (60 trees ha^-1) among the other species. Total basal cover for tree was recorded comparatively higher in case ofMadhuca latifolia(4.86 m²/ha) as compared toFicus religiosa(4.69 m²/ha). In horticultural and shrubs species, the dominant and co-dominant species wereEmblica officinalisandMangifera indicawith their IVI values 15.51 and 14.25, respectively.Emblica officinalisrecorded the highest value of tree density (50 trees ha^-1). In horticultural and shrubs species, the basal cover was recorded markedly higher inMangifera indica(2.58 m²/ha) andEmblica officinalis(0.61 m²/ha).

Table 1: Floristic-diversity of site-I (Dariyapur) of Fatehpur district Click here to View table

Figure 1: Floristic diversity of site-I (Dariyapur) of Fatehpur district Click here to View figure

Table 2: Floristic diversity of site-II (Alampur) of Fatehpur district Click here to View table

Figure 2: Floristic diversity of Site-II (Alampur) Fatehpur, district Click here to View figure

Diversity Index Analysis

Diversity index analysis of vegetation of both sites of the district Fatehpur is presented in Table: 3. A close insight of the data shows that the comparatively higher value of index of dominance (Simpson index) and species diversity (sd) was recorded (0.039) and (0.994) respectively at site –II while lowest (0.934) and (0.032) respectively. In agrihorticultural system highest species of diversity was recorded at site-I (0.330) and lowest at site-II (0.256).

Equitability (e) was found equal value (0.055) in agrisilviculture system at site-I and II whereas in agrihorticulture system the higher value was recorded at site-I (0.36) and minimum in site-II (0.032).

Perusal of data shows that higher species richness was found in agrisilviculture system in site –II (0.154) compared to agrihorticulture system in site –II (0.225). Beta diversity was found highest in agrisilviculture system in site –I (4.176) and lowest at site –II (3.944), whereas in agrihorticulture system it was found highest in site –II (3.875) and lowest at site-I (3.444).

The Shannon-Wiener Index Value (H’) showed that the diversity was almost similar to that in a tropical forest (5.45). H’ value in tropical rain forest generally varies between 5.06 in a young stand to 5.4 in an old stand.¹¹

Table 3: Diversity Index of study sites-I, and II of Fatehpur districts

AF system	Species –Diversity Index (Shannon Index)		Simpson Index(Concent-ration of Dominance)		Species Richness		Equitability		Beta Diversity
	Trees	Shrubs	Trees	Shrubs	Trees	Shrubs	Trees	Shrubs	Trees	Shrubs
AS/SI	0.934	0.084	0.032	0.0003	0.149	0.277	0.055	0.021	4.176	3.500
AS/SII	0.994	0.096	0.039	0.0002	0.154	0.357	0.055	0.024	3.944	3.500
AH/SI	0.330	0.047	0.008	0.0003	0.177	0000	0.036	0.023	3.444	3.000
AH/SII	0.256	0.038	0.003	0.000	0.225	0000	0.032	0.019	3.875	3.000

Conclusions

In view of the above findings, it is concluded that the IVI was recorded maximum inAcacia niloticain both the research sites. As far as concerned to maximum value of Concentration of Dominance (Simpson Index), Equitability, Beta diversity and Species diversity, Site-I (Dariyapur) is superior while species richness was found at site –II (Alampur).

Acknowledgment

The authors gratefully acknowledge the School of Forestry and Environment, Allahabad, Sam Higginbottom University of Agriculture, Technology and Sciences, Allahabad for facilitating this experiment and providing basic facilities.

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