Resource Partitioning by Mangrove Bird Communities in North Australia

Abstract

Mangrove bird communities in north Australia comprise relatively few passerine species compared with other arboreal habitats in the region. Mangroves are dominated by a few tree species and there are potentially few resource axes available for partitioning by terrestrial birds. Competition for limited resources is predicted to cause strong niche differentiation and a highly structured, but low diversity, bird assemblage. Using multivariate and bipartite network analyses based on 1771 foraging observations (33% of 5320 behavioral observations), we examined resource partitioning by 20 terrestrial bird species in mangroves of north Australia. The mangrove bird community largely comprised generalist insectivores that partitioned insects by size with moderate-to-high interspecific overlap in diet. Gleaning for insects was the most common foraging mode. Few species specialized on nectar. Flowers of one or more mangrove species were available in every month of the year and insect abundance was correlated with flowering peaks. Niche differentiation by birds was determined by food type and foraging mode more than by broad spatial (mangrove zones) or temporal (seasonal) segregation of the use of resources. There was little evidence of bird species saturation or species sorting, suggesting loose species packing and a lesser role than expected for species interactions and interference competition in structuring the bird assemblage in mangroves.

Phytochemical Constituents of the Leaves of Leucaena Leucocephala From Malaysia

“…Leucaena leucocephala trees or Petai belalang as it is locally known in Malaysia [1] is a tropical multipurpose tree species. Central America and Southeast Asia's genus, Leucaena (English name), formerly contained approximately 50 species of both trees and shrubs that belonged to the Mimosoideae's subfamily of the Fabaceae family.…”

West African Mangroves Harbour Millions of Wintering European Warblers

“…Why migrant warblers in West Africa prefer low mangroves and the lower part of the canopy (Figure 3) is still unknown. Elsewhere in the world, bird species differ regarding the foraging height in mangroves (Lefebvre et al 1992, Noske 1995, but in general are less specialized in their use of foraging heights than in foraging behaviours (Mohd-Azlan et al 2014).…”

“…Half a century later, Moreau's questions are still unresolved. This is remarkable, especially in the light of detailed studies on the dynamics of bird communities and food resources in Central and South American mangroves (Lefebvre et al 1994, Lefebvre & Poulin 1996, in Malaysia (Noske 1995) and Australia (Mohd-Azlan et al 2014). The single exception is the pioneering study by Altenburg & van Spanje (1989) in Guinea-Bissau.…”

“…And if so, did mangrove forests act as a refugium for Palearctic warblers affected by drought-related habitat loss in the Sahel? In northern Australia, for example, mangroves may provide temporary refugia from fire in adjacent savanna woodland (Mohd-Azlan et al 2014).…”

Stable isotopes reveal opportunistic foraging in a spatiotemporally heterogeneous environment: Bird assemblages in mangrove forests

“…Relative to other forest types, mangroves support few bird species that are obligate habitat (mangrove) specialists and instead host many species with generalized foraging niches [ 11 , 12 , 13 ]. However, foraging niches have traditionally been examined through visual observation or gut content analyses and, unless individuals can be tracked or recaptured, these methods are inappropriate for determining the consistency of an individual’s foraging strategy.…”