Long-term changes in populations of rainforest birds in the Australia Wet Tropics bioregion: A climate-driven biodiversity emergency

Many authors have suggested that the vulnerability of montane biodiversity to climate change worldwide is significantly higher than in most other ecosystems. Despite the extensive variety of studies predicting severe impacts of climate change globally, few studies have empirically validated the predicted changes in distribution and population density. Here, we used 17 years (2000–2016) of standardised bird monitoring across latitudinal/elevational gradients in the rainforest of the Australian Wet Tropics World Heritage Area to assess changes in local abundance and elevational distribution. We used relative abundance in 1977 surveys across 114 sites ranging from 0-1500m above sea level and utilised a trend analysis approach (TRIM) to investigate elevational shifts in abundance of 42 species. The local abundance of most mid and high elevation species has declined at the lower edges of their distribution by >40% while lowland species increased by up to 190% into higher elevation areas. Upland-specialised species and regional endemics have undergone dramatic population declines of almost 50%. The “Outstanding Universal Value” of the Australian Wet Tropics World Heritage Area, one of the most irreplaceable biodiversity hotspots on Earth, is rapidly degrading. These observed impacts are likely to be similar in many tropical montane ecosystems globally.

Response of bird community to gradual landscape transformation in Darmaga campus, IPB University, Bogor, Indonesia

When a landscape gradually transforms, the bird community that inhabits the landscape will also adapt and change accordingly. Long-term data on the bird-habitat relationship, however, is still lacking in the sub-urban tropical areas. The objective of this paper was to analyze the response of bird community along with the gradual transformation of the landscape. Darmaga Campus of IPB University (± 2.67 km2) was selected as the study area due to its landscape transformation for campus development/construction, and the availability of bird monitoring data. Data on landscape transformation were gathered from the IPB building construction book published in 2017, and bird community (1982-2020) were gathered from published reports and papers. During the observed period, Darmaga Campus that initially consisted mostly of old rubber plantation has been gradually transformed into various academic-related uses, such as some areas for buildings dan field laboratories. From 1982 to 2020, the cumulative bird species in the study area at least was 124 species. During the observed years, the bird community was highly dynamics (bird species number in 1982 = 41 species, 1985 = 39 species, 1986 = 68 species, 1991 = 68 species, 2001 = 39 species, 2003 = 72 species, 2013 = 52 species, 2020 = 99 species). New incoming species were Chestnut-winged Cuckoo, Asian Brown Flycatcher, Tiger Shrike, and babblers (e.g., Black-capped Babbler); Brown Shrike, White-rumped Shama, Oriental Magpie-Robin and Green Junglefowl have not been observed or have become increasingly rare in the last ten years. Meanwhile, Red-breasted Parakeet, Fulvous-breasted Woodpecker, Sunda Pygmy Woodpecker, Black Drongo, and Sooty-headed Bulbul are always present species. Bird species such as Orange-headed Thrush, White-rumped Shama, White-browed Shortwing, and Velvet-fronted Nuthatch are species that entered to rarely found species. Gradual landscape transformation, from an old rubber plantation into a mosaic of small patches of human-made ornamental plants, shrub, and tree plantation, turns out to be beneficial for some bird species, but could also disadvantageous for others, causing a dynamic bird community composition.