39 research outputs found
Staving off extinction â more than luck and fate
National Environmental Science Programme Threatened Species Recovery Hu
Counting the bodies: Estimating the numbers and spatial variation of Australian reptiles, birds and mammals killed by two invasive mesopredators
Aim Introduced predators negatively impact biodiversity globally, with insular fauna often most severely affected. Here, we assess spatial variation in the number of terrestrial vertebrates (excluding amphibians) killed by two mammalian mesopredators introduced to Australia, the red fox (Vulpes vulpes) and feral cat (Felis catus). We aim to identify prey groups that suffer especially high rates of predation, and regions where losses to foxes and/or cats are most substantial. Location Australia. Methods We draw information on the spatial variation in tallies of reptiles, birds and mammals killed by cats in Australia from published studies. We derive tallies for fox predation by (i) modelling continental-scale spatial variation in fox density, (ii) modelling spatial variation in the frequency of occurrence of prey groups in fox diet, (iii) analysing the number of prey individuals within dietary samples and (iv) discounting animals taken as carrion. We derive point estimates of the numbers of individuals killed annually by foxes and by cats and map spatial variation in these tallies. Results Foxes kill more reptiles, birds and mammals (peaking at 1071Â kmâ2Â yearâ1) than cats (55Â kmâ2Â yearâ1) across most of the unmodified temperate and forested areas of mainland Australia, reflecting the generally higher density of foxes than cats in these environments. However, across most of the continent â mainly the arid central and tropical northern regions (and on most Australian islands) â cats kill more animals than foxes. We estimate that foxes and cats together kill 697Â million reptiles annually in Australia, 510Â million birds and 1435Â million mammals. Main conclusions This continental-scale analysis demonstrates that predation by two introduced species takes a substantial and ongoing toll on Australian reptiles, birds and mammals. Continuing population declines and potential extinctions of some of these species threatens to further compound Australia's poor contemporary conservation record
Conservation of birds in fragmented landscapes requires protected areas
For successful conservation of biodiversity, it is vital to know whether protected areas in increasingly fragmented landscapes effectively safeguard species. However, how large habitat fragments must be, and what level of protection is required to sustain species, remains poorly known. We compiled a global dataset on almost 2000 bird species in 741 forest fragments varying in size and protection status, and show that protection is associated with higher bird occurrence, especially for threatened species. Protection becomes increasingly effective with increasing size of forest fragments. For forest fragments >50 ha our results show that strict protection (International Union for Conservation of Nature [IUCN] categories IâIV) is strongly associated with higher bird occurrence, whereas fragments had to be at least 175 ha for moderate protection (IUCN categories V and VI) to have a positive effect. This meta-analysis quantifies the importance of fragment size, protection status, and their interaction for the conservation of bird species communities, and stresses that protection should not be limited to large pristine areas
Red hot frogs:Identifying the Australian frogs most at risk of extinction
More than a third of the worldâs amphibian species are listed as Threatened or Extinct, with a recent assessment identifying 45 Australian frogs (18.4% of the currently recognised species) as âThreatenedâ based on IUCN criteria. We applied structured expert elicitation to 26 frogs assessed as Critically Endangered and Endangered to estimate their probability of extinction by 2040. We also investigated whether participant experience (measured as a self-assigned categorical score, i.e. âexpertâ or ânon-expertâ) influenced the estimates. Collation and analysis of participant opinion indicated that eight species are at high risk (>50% chance) of becoming extinct by 2040, with the disease chytridiomycosis identified as the primary threat. A further five species are at moderateâhigh risk (30â50% chance), primarily due to climate change. Fourteen of the 26 frog species are endemic to Queensland, with many species restricted to small geographic ranges that are susceptible to stochastic events (e.g. a severe heatwave or a large bushfire). Experts were more likely to rate extinction probability higher for poorly known species (those with <10 experts), while non-experts were more likely to rate extinction probability higher for better-known species. However, scores converged following discussion, indicating that there was greater consensus in the estimates of extinction probability. Increased resourcing and management intervention are urgently needed to avert future extinctions of Australiaâs frogs. Key priorities include developing and supporting captive management and establishing or extending in-situ population refuges to alleviate the impacts of disease and climate change
How many bird and mammal extinctions has recent conservation action prevented?
Aichi Target 12 of the Convention on Biological Diversity (CBD) aims to âprevent extinctions of known threatened speciesâ. To measure its success, we used a Delphi expert elicitation method to estimate the number of bird and mammal species whose extinctions were prevented by conservation action in 1993 - 2020 (the lifetime of the CBD) and 2010 - 2020 (the timing of Aichi Target 12). We found that conservation prevented 21â32 bird and 7â16 mammal extinctions since 1993, and 9â18 bird and 2â7 mammal extinctions since 2010. Many remain highly threatened, and may still become extinct in the near future. Nonetheless, given that ten bird and five mammal species did go extinct (or are strongly suspected to) since 1993, extinction rates would have been 2.9â4.2 times greater without conservation action. While policy commitments have fostered significant conservation achievements, future biodiversity action needs to be scaled up to avert additional extinctions
How many bird and mammal extinctions has recent conservation action prevented?
Aichi Target 12 of the Convention on Biological Diversity (CBD) contains the
aim to âprevent extinctions of known threatened speciesâ. To measure the degree
to which this was achieved, we used expert elicitation to estimate the number
of bird and mammal species whose extinctions were prevented by conservation
action in 1993â2020 (the lifetime of the CBD) and 2010â2020 (the timing of Aichi
Target 12). We found that conservation action prevented 21â32 bird and 7â16
mammal extinctions since 1993, and 9â18 bird and two to seven mammal extinctions
since 2010. Many remain highly threatened and may still become extinct.
Considering that 10 bird and five mammal species did go extinct (or are strongly
suspected to) since 1993, extinction rates would have been 2.9â4.2 times greater
without conservation action. While policy commitments have fostered significant
conservation achievements, future biodiversity action needs to be scaled up
to avert additional extinctions.https://wileyonlinelibrary.com/journal/conlMammal Research Institut
The impacts of fire on birds in Australia's tropical savannas
The ecology of Australia's tropical savannas is shaped by the near-pervasive influence of fire. Constituting âŒ20% of Australia's land area, tropical savannas contribute >75% of the area burnt in Australia each year. Across most of Australia's tropical
Uneven distribution of weeds along extensive transects in Australiaâs Northern Territory points to management solutions
The Top End region of the Northern Territory, Australia, is noted for its relatively unmodified natural state. To gain some insight into the potential for maintaining ecosystem health in this region we undertook a study that assessed the distribution of weeds across very extensive transects. This weed survey was distinct from other studies in that many of the sample sites were distant from tracks or other infrastructure. Twenty-one weed species were recorded along 2000 km of transects. Weeds were reported from 18.7% of the 718 sample points. The incidence of weeds was found to be significantly associated with land tenure, being highest on pastoral lands and peri-urban areas, and very low on Aboriginal lands. The incidence of weeds increased significantly with increasing levels of infrastructure and with increasing proximity to watercourses. There are three main conclusions from this study. First, much of the Top End, particularly remote Aboriginal lands, has exceptionally low levels of weed infestation. Secondly, in such areas, given the relatively small extent of vegetation change through weed invasion, maintenance or re-imposition of traditional fire regimes should be achievable. Thirdly, there is substantial potential for spread of weeds to remote areas, with such spread most likely to occur through increased penetration by infrastructure. Importantly this study indicates that there is still opportunity to prevent widespread weed invasion across the Top End, which is timely given the current Government consideration of the potential for the region to support future agricultural expansion and the fast-paced development of mining, oil and gas resources
Patterns of grassland productivity, composition and seed abundance, and the diet of the flock bronzewing pigeon Phaps histrionica at one site in northern Australia over a period of marked seasonal change
Context Multiple scales of research are needed to understand the ecology and conservation requirements of species whose ecology is characterised by marked spatial and temporal dynamism. The flock bronzewing pigeon may provide a model for the conservatio