Do fragmented coastal heathlands have habitat value to birds in eastern Australia?
In: Wildlife research, Band 28, Heft 1, S. 17
ISSN: 1448-5494, 1035-3712
This study investigated the effects of habitat clearance and fragmentation on
birds of coastal heathlands in subtropical eastern Australia. Abundance and
species composition were compared among two types of cleared habitat
(residential suburbs and sugar cane cropland) and four sizes of heathland
remnant (1–2 ha, 5–10 ha, 20–50 ha and >500 ha) in summer
and winter. Cleared land contained a distinctly different bird species
assemblage from heathland remnants. Residential sites contained a distinct
suite of species consistent with that described for 'open/developed
land' habitat elsewhere in the region. In contrast, cane cropland
supported very few species. Heathland remnants >500 ha contained high
densities of 'natural-vegetation-dependent' species, whereas
species of open/developed land were absent. Remnants of 1–2 ha had
lowered densities of many natural-vegetation-dependent species, and a
relatively high abundance of open/developed land species. Some of the
avifaunal differences in the >500-ha remnants and 5–50-ha range are
probably due to confounding of remnant size with habitat, resulting from
selective clearing of the landscape. Most of the heathland birds were
intolerant of the matrix habitat (residential and cane cropland), but tolerant
of decreased remnant area, down to a threshold of about 5 ha. However, the
distinctive floristic associations of heathland vegetation are dependent on an
environmental regime (low nutrient, low pH, fire, in some cases inundation)
that is unlikely to persist in remnants tens of hectares in size, and
longer-term declines in heathland birds, are predicted.