The conservation implications of bird reproduction in the agricultural “matrix”: a case study of the vulnerable superb parrot of south-eastern Australia

Where agriculture has recently been imposed on natural systems, habitats that are modified, but not destroyed, within the agricultural matrix, are often, undervalued for their conservation benefits. Ecological research in the agricultural matrix in such landscapes has been limited in many countries. Yet many organisms live and breed in these landscapes. This paper outlines a large-scale case study of the vulnerable superb parrot that breeds in trees in the agricultural matrix of south-eastern Australia. Superb parrot nest trees were located, measured and compared with a set of randomly chosen non-nest trees. Increasing tree diameter had the largest influence over whether a superb parrot nested in a tree. There was a strong preference for nesting in dead trees and Blakely's red gum. There was limited eucalypt regeneration surrounding trees. The large size and poor health of nest trees requires urgent habitat management to provide alternative nest sites and regenerate trees across the whole agricultural matrix. This will require a long-term vision on the scale of centuries.     

Bird species abundance–occupancy patterns and sensitivity to forest fragmentation: Implications for conservation in the Brazilian Atlantic forest

Developing a predictive theory for species responses to habitat fragmentation is a large, complex challenge in conservation biology, and meeting this challenge likely requires tailoring predictions to specific habitats and taxa. We evaluate the effects of fragmentation on forest birds living in three distinct forest ecosystems found in Brazilian Atlantic forest: seasonal semi-deciduous forest (SF), mixed rain forest (MF), and dense rain forest (DF). We test the hypotheses that (1) bird species most prevalent in SF (relative to other habitat types) will be least vulnerable to population declines in fragmented SF, and (2) species with stronger affiliations with DF or MF will be relatively more sensitive to fragmentation in SF. Using an exploratory statistical technique called “Rank Occupancy–Abundance Profiles (ROAPs),” we compared distribution and abundance of birds among large “continuous” areas of each forest type, then compared abundances in continuous SF forests with patterns of abundance in small fragments of SF, where edge effects could play a marked role in population dynamics. Overall, 39 species showed substantially lower local abundance, occupancy, or both in SF fragments versus continuous SF. As predicted, a higher proportion of bird species associated with DF appeared sensitive to fragmentation in SF; by contrast, species most abundant in SF and MF were similarly abundant in fragmented SF. Our study demonstrates how quantifying distribution and abundance in diverse habitats may enhance managers’ ability to incorporate species-specific responses to human disturbances in their conservation plans, and points out ways that even small reserves may have significant conservation value.