Edge effects in the avifaunal community of riparian rain-forest tracts in Tropical North Queensland

Abstract

Most evidence suggests anthropogenic edges negatively affect rain-forest bird communities but little has been done to test this in Australasia. In this study, avifaunal detection frequency, species richness and community composition were compared between the edge and interior and between flat and more complex-shaped edges of riparian rain-forest tracts in Tropical North Queensland. The detection frequency and richness of guilds based on diet, foraging strata and habitat specialism were also compared. This study detected 15.1% more birds at the rain-forest edge compared with the interior but no difference in species richness. Edge shape had no effect on detection frequency or richness. Many guilds (subcanopy, closed forest, frugivorous and insectivorous species) experienced increased detection frequency at the edge relative to the interior, but for some guilds this response was reduced (habitat generalists) or reversed (understorey and mixed-flock species) along complex edges. Overall community composition was affected by edge distance but not by edge shape. Edge habitat was shorter and had more open canopy than the interior, supporting habitat-based explanations for the observed avifaunal edge effects. These results suggest generally positive edge effects in Australian rain-forest bird communities, possibly reflecting local resource distributions or a disturbance-tolerant species pool

Elevational changes in the avian community of a Mesoamerican cloud forest park

“…, Neate‐Clegg et al . ). However, more species in general are lost than gained through habitat conversion in the tropics (Waltert et al .…”

“…Deforestation can negatively impact forest interior specialists both through the direct loss of habitat and via edge effects on remaining forests (Laurance 2004, Banks-Leite et al 2010. Forest edges and agropastoral mosaics do have the potential to harbor reasonable amounts of bird diversity (Ricketts et al 2001, S ßekercio glu et al 2007, Neate-Clegg et al 2016. However, more species in general are lost than gained through habitat conversion in the tropics , Mahood et al 2012, resulting in lower species turnover (Moura et al 2013, de Castro Solar et al 2015 particularly along elevational gradients (Sreekar et al 2017).…”

Negros Bleeding-heartGallicolumba keayiprefers dense understorey vegetation and dense canopy cover, and species distribution modelling shows little remaining suitable habitat

“…The model also highlights that large proportions of the core areas inside many IBAs and protected areas maybe less suitable than previously thought, particularly within the protected areas of the North Negros Natural Park and Mt Kanla-on Natural Park, and the unprotected IBAs of the Central Panay Mountains and Cuernos de Negros, with some edge areas appearing more suitable than within the core area. This is a particular concern because the edges of reserves are often subject to abiotic edge effects that can reduce habitat quality, particularly for understorey birds (Pohlman et al 2007; Neate-Clegg et al 2016), and to greater human pressures, such as encroachment for agriculture, charcoal logging or hunting by those living on the borders (Pedregosa-Hospodarsky et al 2009).…”

Functional Diversity Metrics: How They Are Affected by Landscape Change and How They Represent Ecosystem Functioning in the Tropics

“…This indicates that functional diversity exhibits greater heterogeneity in fragments (especially edges) as opposed to continuous forest, but patterns were less clear when considering only species occurrence as opposed to abundance [43]. (2) Edge effects: The altered abiotic conditions in edge habitats [44] can have substantial effects upon community and ecosystem processes [45,46], and edge effects may even be the cause of many observed area effects [47]. Despite such pervasive impacts, we could not find a consensus regarding their effects on functional diversity metrics ( Table 1).…”