Skip to main content

Search the SPREP Catalogue

Refine Search Results

Tags / Keywords

Available Online

Tags / Keywords

Available Online

46000 result(s) found.

Sort by

The red vented-bulbul (Pycnonotus cafer): invasion dynamics and ecological impacts of an introduced pest bird in New Caledonia and implications for management
BRB
Available Online

Martin Thibault

2018
Suite à la soutenance de thèse effectuée en juillet 2018 à l’Université de Massey, le manuscrit de Martin Thibault, intitulé « Le bulbul à ventre rouge (Pycnonotus cafer): dynamique d’invasion et impacts écologiques d’un oiseau introduit en Nouvelle Calédonie. Invasive alien species are a major cause of biodiversity loss globally, especially on islands where high species richness and levels of endemism accentuate their impacts. Various international institutions have constructed lists of the most harmful invasive species to help environment managers at both global and local scales to prioritize their efforts. The red-vented bulbul (Pycnonotus cafer) is a passerine bird species considered among the three worst invasive birds on the planet. This species is currently spreading over the tropical archipelago of New Caledonia, one of the 36 world biodiversity hotspots. This dissertation presents the findings of a PhD study conducted in New Caledonia with two objectives: 1) to describe this introduced population, and 2) to evaluate the threats from its dispersal using both existing knowledge and new in-situ and ex-situ data and a variety of analysis techniques. From the literature, I identified three key impacts explaining the species’ status: i) damage to agricultural crops, ii) noxious seed dispersal, and iii) competition with other avifauna. I estimated the local population size (approx. 140,000 individuals), its habitat use (inhabited areas), its density along an urbanization gradient (30-120 ind/km2), and I produced lists of consumed plant and animal species and identified a colour preference in the foraging strategy of the red-vented bulbul. Exploration of each impact category revealed i) substantial losses on fruit production (18% of tomato production), ii) impact on the abundance of nine native bird species that may be driving a spatial reassembly of the community, and iii) a short distance dispersal (77-92 m) that could promote the dispersal of introduced plant species at the expense of endemic species. Finally, through modelling, I estimated the climatic niche of the species at a global scale and identified that most island territories as suitable for the establishment of this invasive bird species. Regardless of whether the red-vented bulbul deserves its status as “world worst” species, quantitative impact assessments in its alien range such as the studies presented here are needed to prevent the dispersal and harmful impacts of this species on human activities and sensitive ecosystems. Implications for management are discussed.
Global evidence that deforestation amplifies flood risk and severity in the developing world
BRB
Available Online

Bradshaw, Corey J. A.

,

Brook, Barry W.

,

Peh, Kelvin S. H.

,

Sodhi, Navjot S.

2007
With the wide acceptance of forest?protection policies in the developing world comes a requirement for clear demonstrations of how deforestation may erode human well?being and economies. For centuries, it has been believed that forests provide protection against flooding. However, such claims have given rise to a heated polemic, and broad?scale quantitative evidence of the possible role of forests in flood protection has not been forthcoming. Using data collected from 1990 to 2000 from 56 developing countries, we show using generalized linear and mixed?effects models contrasted with information?theoretic measures of parsimony that flood frequency is negatively correlated with the amount of remaining natural forest and positively correlated with natural forest area loss (after controlling for rainfall, slope and degraded landscape area). The most parsimonious models accounted for over 65% of the variation in flood frequency, of which nearly 14% was due to forest cover variables alone. During the decade investigated, nearly 100?000 people were killed and 320 million people were displaced by floods, with total reported economic damages exceeding US$1151 billion. Extracted measures of flood severity (flood duration, people killed and displaced, and total damage) showed some weaker, albeit detectable correlations to natural forest cover and loss. Based on an arbitrary decrease in natural forest area of 10%, the model?averaged prediction of flood frequency increased between 4% and 28% among the countries modeled. Using the same hypothetical decline in natural forest area resulted in a 4–8% increase in total flood duration. These correlations suggest that global?scale patterns in mean forest trends across countries are meaningful with respect to flood dynamics. Unabated loss of forests may increase or exacerbate the number of flood?related disasters, negatively impact millions of poor people, and inflict trillions of dollars in damage in disadvantaged economies over the coming decades. This first global?scale empirical demonstration that forests are correlated with flood risk and severity in developing countries reinforces the imperative for large?scale forest protection to protect human welfare, and suggests that reforestation may help to reduce the frequency and severity of flood?related catastrophes.