Abstract Detail


Vyas , Amal K [1], GOWDA, VINITA [1].

Patient Impatiens : partitioning and cooperativity in congeneric sympatric Impatiens spp. (Balsaminaeceae) In Kaas plateau, Maharashtra.

According to Gause's competitive exclusion principle, two species competing for the same limiting resource cannot co-exist. Such species should divide the resources in a way that minimizes their competition and maximizes their utilization of the limiting resource. This division of resources is called “niche partitioning”. In Kaas, four congeneric Impatiens (Balsaminaceae): Impatiens dalzellii, Impatiens tomentosa, Impatiens lawii and Impatiens balsamina var. rosea (rosea), are sympatric, co-flowering and share their pollinator space. This study examines the ecological interactions between four congeneric sympatric species towards a common resource i.e. pollinators. We addressed three questions, (i)  are there any phenological differences in the flowering of the Impatiens spp. in Kaas? (ii) Are there any morphological partitioning in floral traits and temporal partitioning in floral rewards among the four sympatric Impatiens spp.? (iii) Do the pollinators show preference towards any species? To check for the morphological differentiation we measured floral traits including spectrophotometric data for all the four species. To compare reproductive phenologies, flower density count was taken from 102 random 1m2 plots, from August to October months. We also measured ecological traits such as pollinator visitations, and nectar concentrations at different time intervals. Finally, a choice experiment was performed to test whether species density or type of species affect pollinator preferences. Our results show a phenological partitioning in mass-flowering between (1) I. lawii and I. tomentosa, and (2) I. lawii and rosea. There are clear morphological partitions between (1) rosea and other three species, and (2)  I. dalzellii and I. lawii. In addition, PCA analysis of spectral reflectance patterns showed that I. dalzellii has a very unique pattern compared to others. We also found a diurnal variation in nectar concentration and visitation rate which further shows that there is temporal partitioning between co-flowering rosea and I.tomentosa (p-value< 0.01). The lack of observed pollinators, as well as the presence of fruit in the bagged inflorescence of I. dalzellii, implies the existence of a selfing mechanism in the habitat. Our choice experiments show that the density of plants did affect the visitation frequencies of the pollinators suggesting that natural plant densities are important even in massively co-flowering species for attracting pollinators (p-value <0.05). The results conclude that all four Impatiens spp. on Kaas plateau share and attract similar pollinators and avoid competition through a combination of phenological, morphological and temporal niche partitioning.

1 - Indian Institute of Science Education and Research Bhopal, Department of Biological Sciences, Room no: 303, Academic Building 3, IISER Bhopal, , Bhauri, Bhopal by pass road, Madhyapradesh, India, Bhopal, Madhya Pradesh, 462066, India

ecological niche partitioning
pollination competition
pollinator preference
Sympatric congeneric species

Presentation Type: Oral Paper
Session: ECO6, Ecology 6: Reproductive Ecology
Location: Virtual/Virtual
Date: Friday, July 31st, 2020
Time: 10:15 AM
Number: ECO6002
Abstract ID:808
Candidate for Awards:None

Copyright © 2000-2020, Botanical Society of America. All rights reserved