Pollinator Diversity and Floral Calendar of Forage Resources for Pumpkin, Machakos County, Kenya

Abstract

The abundance and diversity of bees correlate with the abundance and diversity of forage resources. Pollinator reservoirs in croplands can augment pollination of flowering crops by increasing pollinator diversity and abundance. Therefore, this study provides empirical evidence on the diversity and abundance of alternative forage resources in two landscape classes with pumpkin fields. The study was undertaken in 32 pumpkin farms; 16 for each natural difference vegetation index (NDVI classes). Flowering plants were identified and counted within and around farms at 2 m × 2 m quadrat and 4 m × 50 m belt transect from the middle of the farm towards the exit. Approximately 142 plant species were recorded and their abundance varied between NDVI classes and across months. In the 2 m × 2 m quadrat 6,765 plants were observed in May in low NDVI and 4,399 in medium NDVI were recorded in May. Abundance, diversity and annual floral resource structure for honeybees in low and medium Normalized difference vegetation index (NDVI) classes in Machakos County were determined. The 4 m × 50 m belt transect had the highest numbers of plants (1,434-20,825) and plant species across the months and between NDVI classes. At least 35% of plants remained actively flowering during the sampling period, therefore, can serve as alternative forage sources for pollinators. Our inventory of plants can be used to develop a floral calendar for adoption by farmers for on-farm management of pollinators. The floral calendars will be predictive tools used to detect a correlation between flowering plants, seasons and pollinators.