Effects Of Agroecosystem Land Use On The Diversity, Abundance, And Ecosystem Functions Of Insect Pollinators Of Passion (Passiflora Edulis) Crop

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ABSTRACT

Worldwide, crops that require wild pollinators are showing a deficiency of pollination

and genetic variation. In the recent past, studies show that there has been a steady

decline in production of passion fruits in Kenya. In this study, the major objective was

to investigate factors causing the decline of passion fruit production using ecosystem

concepts, agricultural practices and social-ecological factors using the case scenario

of Mua hills in Machakos County.

The study was carried out during the wet season December, 2015 and the dry season

early March, 2016. The farms sampled in each Agro-ecological zone were categorized

according to three land use types; horticulture, mixed cropping, and natural patches

near each farm which served as the control sites. During sampling on average 1415

insects were collected belonging to 30 species, 10 families and 8 orders. The results

indicated that diversity and evenness of bees, which are the main pollinator of passion

fruit was much higher in Zone V than in Zone IV and Zone III. There was seasonal

variation in abundance although this did not affect the diversity of the insect

pollinators. Results of Pearson’s correlation analysis between number of fruits and

insect abundance per AEZ revealed that there was a positive and significant

association between the abundance of the insects and the number of fruits (r = 0.504,

p = 0.002). The study findings revealed that 76.7% of the farmers use the DAM,

CAN, DAP type of agrochemicals while 23.3% of the respondents use other types of

agrochemicals. For plant richness, a total of fifteen (15) higher plant species, three (3)

shrubs and sixteen herbs (16) were recorded. This study revealed that land use type

and agro-chemicals could be key factors in determining insect pollinator diversity and

abundance in different agro-ecological zones. The findings from this research echo

the need for environmental management of agro-ecosystems to support ecosystem

services in particular pollination which improves passion fruit production.