Ciconiiformes Nesting on Trees in Cereal-Dominated Farmlands: Importance of Scattered Trees for Heronries in Lowland Nepal

Abstract

Cereal farming is on the increase globally, and trees on these agricultural landscapes are selectively removed by farmers. Waterbird populations, supported on many cereal farmlands, need trees to place heronries and can be impacted by farmers' habits. In a cereal-dominated landscape in lowland Nepal, a landscape-scale field design was used to quantify characteristics of existing trees (density, species, girth, height), and contrasted against heronry trees to understand how choice of nest trees by select Ciconiiformes species was affected by farmers' habits. Tree density was patchy and tree species richness low, dominated by two tree species that had direct utility to farmers (Dalbergia sissoo – timber; Mangifera indica – fruits). Heronries were preferentially located on two wild tree species that were 8% of available trees and were either revered in local religion (Ficus religiosa; 36% of all heronries) or favored for agroforestry (Bombax ceiba; 42%). Heronries were preferentially located on larger trees. Availability of suitable trees for heronries was reduced by farmers' habits, but religious beliefs and agroforestry continued to support multi-functionality of cereal-dominated cropfields in lowland Nepal.