Population densities and conservation status of Norfolk Island forest birds

SummaryThree weeks of intensive surveys in Norfolk Island National Park in 2009 failed to find White-chested White-eye Zosterops albogularis and it was calculated that there was a less than 17% probability that a population of 10 birds had been overlooked. The last multi-observer record of this species was in 1978, and it is recommended that the species’ IUCN Red List status of “Critically Endangered” is tagged as “Possibly Extinct”. During these surveys, the population densities of seven bird species were calculated from 352 independent point counts. Causes of imprecision and bias were investigated, suggesting a small underestimation. Other species were recorded too infrequently, or their distributions were too biased, for analysis. The population densities of the extant endemic taxa were relatively high and suggest no current declines, and the population estimates were consistent with previous studies. This study recommends monitoring most species by point counts, or line transects if resources are limited, supplemented with specific monitoring of Tasman (Norfolk Island) Parakeet Cyanoramphus cookii, Pacific Robin Petroica multicolor, Southern Boobook Ninox novaeseelandiae and seabirds. Ongoing monitoring of these birds is needed to help inform management of the National Park and the island in general, given their small population sizes and their likely susceptibility to rat and cat predation, competition from alien species and drought.

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Out of the darkness: the first comprehensive survey of the Critically Endangered Anjouan Scops Owl Otus capnodes

Bird Conservation International ◽

10.1017/s0959270914000185 ◽

2014 ◽

Vol 25 (3) ◽

pp. 322-334 ◽

Cited By ~ 1

Author(s):

KATHLEEN E. GREEN ◽

BRONWEN M. DANIEL ◽

SAMUEL P. LLOYD ◽

ISHAKA SAID ◽

AMELAID HOUMADI ◽

...

Keyword(s):

Population Size ◽

Conservation Status ◽

Distance Sampling ◽

Bird Species ◽

Iucn Red List ◽

Critically Endangered ◽

Encounter Rate ◽

Wet Season ◽

Point Counts ◽

Comprehensive Survey

SummaryAlthough birds are among the best studied taxa, many of the globally threatened species lack the information required to fully assess their conservation status and needs. One such species is the Anjouan Scops Owl Otus capnodes which was presumed extinct until its rediscovery to science in 1992. Based on the limited extent and decline of the moist forests in the highlands of Anjouan in the Comoro Islands, a population size of only 100–200 pairs was estimated and the species was classified as ‘Critically Endangered’. The current study is the first comprehensive survey ever conducted on this species, and aimed to establish the current distribution and population size. Point counts with distance sampling were conducted across the agroforestry and forest zones of Anjouan in both a dry and wet season. A niche suitability model predicted the species distribution to be wider than expected with owls observed as low as 300 m altitude and in highly modified agroforestry habitats. However, the encounter rate in natural relatively undisturbed forest was significantly greater than in other habitats. The wider than expected geographic range of O. capnodes supports a possible downlisting of this species on the IUCN Red List to ‘Endangered’. Population size was found to be far greater than previously thought, at approximately 3,450 individual owls in the dry season and 5,450 in the wet season. These results show the importance of investing in robust surveys of poorly known and cryptic bird species, and provide up to date and important information for landscape scale conservation planning in the Comoros Islands.

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Wildlife Trade Influencing Natural Parrot Populations on a Biodiverse Indonesian Island

Diversity ◽

10.3390/d13100483 ◽

2021 ◽

Vol 13 (10) ◽

pp. 483

Author(s):

Dudi Nandika ◽

Dwi Agustina ◽

Robert Heinsohn ◽

George Olah

Keyword(s):

National Park ◽

Conservation Status ◽

Wildlife Trade ◽

Population Status ◽

Point Counts ◽

In The Wild ◽

Line Transects ◽

Fixed Radius ◽

Parrot Species ◽

Multiple Species

Indonesia has been identified as the highest priority country for parrot conservation based on the number of species, endemics, and threats (trapping and smuggling). It is crucial to understand the current population status of parrots in the wild in relation to the illegal wildlife trade but the ecology and population dynamics of most parrot species in this region remain poorly understood. We conducted a parrot survey around an area of high biodiversity in the Manusela National Park, in Seram Island, Indonesia. We used a combination of fixed-radius point counts and fixed-width line transects to count multiple species of parrots. We recorded nearly 530 wild parrots from 10 species in and around Manusela National Park. The dominant parrot species were Eos bornea, Trichoglosus haematodus, and Geoffroyus geoffroyi. We applied the Savage selectivity index to evaluate poaching of parrot species in proportion to their abundance and which species had higher than expected poaching pressure. This study has important implications for the conservation status of endemic parrots (Cacatua moluccensis, Lorius domicella, and Eos semilarvata) and shows that parrots in the Manusela NP are largely threatened by poaching.

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How many bird extinctions have we prevented?

Oryx ◽

10.1017/s0030605306000950 ◽

2006 ◽

Vol 40 (3) ◽

pp. 266-278 ◽

Cited By ~ 101

Author(s):

Stuart H.M. Butchart ◽

Alison J. Stattersfield ◽

Nigel J. Collar

Keyword(s):

Invasive Species ◽

Captive Breeding ◽

Extinction Risk ◽

Bird Species ◽

Iucn Red List ◽

Additional Species ◽

Conservation Actions ◽

Declining Populations ◽

Population Sizes ◽

Principal Actions

Considerable resources and efforts have been directed at biodiversity conservation in recent years, but measures of the success of conservation programmes have been limited. Based on information on population sizes, trends, threatening processes and the nature and intensity of conservation actions implemented during 1994–2004, we assessed that 16 bird species would have probably become extinct during this period if conservation programmes for them had not been undertaken. The mean minimum population size of these 16 species increased from 34 to 147 breeding individuals during 1994–2004. In 1994, 63% of them had declining populations but by 2004, 81% were increasing. Most of these species (63%) are found on islands. The principal threats that led to their decline were habitat loss and degradation (88%), invasive species (50%) and exploitation (38%), a pattern similar to that for other threatened species, but with exploitation and invasive species being relatively more important. The principal actions carried out were habitat protection and management (75% of species), control of invasive species (50%), and captive breeding and release (33%). The 16 species represent only 8.9% of those currently classified as Critically Endangered, and 1.3% of those threatened with extinction. Many of these additional species slipped closer to extinction during 1994–2004, including 164 that deteriorated in status sufficiently to be uplisted to higher categories of extinction risk on the IUCN Red List (IUCN, 2006). Efforts need to be considerably scaled up to prevent many more extinctions in the coming decades. The knowledge and tools to achieve this are available, but we need to mobilize the resources and political will to apply them.

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Artificial Wetlands as Breeding Habitats for Colonial Waterbirds within Central Romania

Diversity ◽

10.3390/d12100371 ◽

2020 ◽

Vol 12 (10) ◽

pp. 371

Author(s):

Dan Traian Ionescu ◽

Călin Vasile Hodor ◽

Ion Cătălin Petritan

Keyword(s):

Conservation Status ◽

Bird Species ◽

Natura 2000 ◽

Positive Trend ◽

Phalacrocorax Carbo ◽

Artificial Wetlands ◽

Nycticorax Nycticorax ◽

Ardea Alba ◽

Colonial Waterbirds ◽

Population Sizes

The historical loss of natural wetlands in Romania is significant. The building of lakes, ponds, and dams has compensated for some of these losses, as was the case in the study area, the artificial wetlands designated as the Natura 2000 (special protection area, SPA) and Ramsar sites. In this context, to evaluate the conservation status of colonial waterbirds (cormorants, herons, and egrets), we analyzed actual distributions, habitat selection, features, and population sizes. Standardized counting of colonial species was used, supplemented by nest counting and colony-area estimation during winter, and drone footage. All species and their colonies were built in artificial or anthropically influenced habitats. Concerning distribution and population sizes, Phalacrocorax carbo and Microcarbo pygmeus were found to nest only in central Romania. The pair numbers of Ardea alba, Ardea purpurea, Ardea cinerea, and Nycticorax nycticorax in the area exceeded 1% of the national minimum breeding population. There was a statistically significant positive trend of breeding populations for Ardea alba, Nycticorax nycticorax, and Egretta garzetta. In conclusion, these artificial wetlands offer optimal breeding conditions for a relatively large diversity of colonial bird species over areas that are not very large.

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Conservation status of Mascarene Amaranth Aerva congesta Balf.F. Ex Baker (Eudicots: Caryophyllales: Amaranthaceae): a Critically Endangered endemic herb of the Mascarenes, Indian Ocean

Journal of Threatened Taxa ◽

10.11609/jott.2402.10.8.12056-12063 ◽

2018 ◽

Vol 10 (8) ◽

pp. 12056

Author(s):

Kersley Bruno Pynee ◽

David Harold Lorence ◽

Poojanraj Khurun

Keyword(s):

Conservation Status ◽

Iucn Red List ◽

Small Population ◽

Red List ◽

Critically Endangered ◽

Native Vegetation ◽

Ecological Studies ◽

Area Of Occupancy ◽

Mascarene Islands ◽

Iucn Red List Criteria

Aerva congesta Balf.f. ex Baker (Amaranthaceae), an endemic of Mascarene Islands (Mauritius and Rodrigues) is assessed for its conservation status. Considering its local extinction in Rodrigues and very small population in Mauritius, in Round Island and at Gris Gris, south of Mauritius its area of occupancy (AOO) is estimated at 8km². Due to its small AOO and threats by increasing native vegetation and alien species, A. congesta is evaluated as Critically Endangered following the latest IUCN Red List criteria. The species needs an urgent well-defined restoration program and ecological studies to prevent its extinction.

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Mangrove vegetation and bird communities around Tegal Port, Central Java, Indonesia

Biodiversitas Journal of Biological Diversity ◽

10.13057/biodiv/d210436 ◽

2020 ◽

Vol 21 (4) ◽

Author(s):

Slamet Isworo ◽

POERNA SRI OETARI

Keyword(s):

Diversity Index ◽

Conservation Status ◽

Bird Species ◽

Similarity Index ◽

Iucn Red List ◽

Red List ◽

Bird Communities ◽

Central Java ◽

Wiener Diversity Index ◽

Mangrove Vegetation

Abstract. Isworo S, Oetari PS. 2020. Mangrove vegetation and bird communities around Tegal Port, Central Java, Indonesia. Biodiversitas 21: 1551-1560. The ecological balance in Tegal harbor area needs to get serious attention due to the impacts of Tegal Port activities. For this purpose, the diversity of mangrove and avifauna (bird) can be used as bio-indicators of the ecological stability of the area. This study aimed to assess and analyze the diversity of plants and avifauna (birds) that live in mangrove and coastal zones around Tegal Port development area. Data collection was conducted using purposive random sampling method on two sites for vegetation and three sites for avifauna. The importance value index, Shannon-Wiener diversity index and Sorensen’s similarity index was calculated for the vegetation. For birds, we calculated the diversity and similarity index as well as identified their conservation status based on the IUCN Red List, CITES and government regulations. In terms of vegetation, Rhizophora mucronata and Avicennia marina dominate Site 2 (Tegalsari) while Casuarina equisetifolia and R. mucronata dominate Site 3 (Alam Indah Beach). Overall, the vegetation has low biodiversity index and similarity between sites is also low. For bird, there are 37 species from 18 families. Site 1 (Muara Reja) has the highest number of species with 29 species, followed by Site 2 (Tegalsari) with 25 species, and Site 3 (Alam Indah Beach) with 22 species. The three sites have moderate diversity index and there is high similarity index between sites. All bird species found in the study sites are listed as Least Concern under IUCN Red List, while there are two species protected under national protection law, i.e. Ardea alba and Glareola maldivarum. In general, the condition of mangrove vegetation around Tegal Port has low diversity. This suggests that the pressure on the environment is quite high, causing only few plant species to be able to live and dominate the ecosystem. The limited vegetation also causes birds community, especially the protected A. alba and G. maldivarum in Site 2, becomes increasingly difficult to find, because places to find food, breeding places and places to rest are disturbed.

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THE CONSERVATION STATUS OF BATS (MAMMALIA: CHIROPTERA) IN CAT BA NATIONAL PARK, NORTHERN VIETNAM

10.18173/2354-1059.2020-0052 ◽

2020 ◽

Vol 65 (10) ◽

pp. 92-98

Author(s):

Thong Vu Dinh ◽

Southaphan Sichanh ◽

Nha Pham Van

Keyword(s):

National Park ◽

Conservation Status ◽

Taxonomic Status ◽

Iucn Red List ◽

Current Status ◽

Future Research ◽

Field Surveys ◽

Northern Vietnam ◽

Literature Reviews ◽

Conservation Actions

Prior to the present study, literature reviews revealed that 31 species of bats belonging to six families and 14 genera were identified in Cat Ba National Park in Northern Vietnam However, the conservation status of many species remains unclear and is still subject to debate. Among the 31 species, 11 are common while the remainder have been rarely captured since 1942. At least two species, Hipposideros alongensis and H. khaokhouayensis, which are globally considered vulnerable, are very common in Cat Ba National Park. This paper provides an update on the current status of each species based on data from recent field surveys with reference to previous publications and the current IUCN Red List (iucnredlist.org). Results from the recent surveys included eight individuals provisionally identified as Myotis cf. pilosus. The taxonomic status of five species (Aselliscus dongbacanus, Hipposideros gentilis, Hipposideros grandis, Miniopterus magnater, Murina harrisoni) are updated following recent assessments. This information will inform future research and conservation actions.

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Population density and habitat loss of Chestnut-headed Partridge Arborophila cambodiana in south-west Cambodia

Bird Conservation International ◽

10.1017/s095927091800045x ◽

2018 ◽

Vol 29 (4) ◽

pp. 515-526

Author(s):

SOPHEA CHHIN ◽

NICHOLAS J. SOUTER ◽

DUSIT NGOPRASERT ◽

STEPHEN J. BROWNE ◽

TOMMASO SAVINI

Keyword(s):

Forest Cover ◽

Bird Species ◽

Iucn Red List ◽

Red List ◽

Camera Traps ◽

Evergreen Forest ◽

Mountain Range ◽

Potential Habitat ◽

South West ◽

Line Transects

SummaryThirty-two percent of bird species in South-East Asia are likely to become extinct by the end of this century. However, due to a lack of data this number may be an underestimate. The Chestnut-headed Partridge Arborophila cambodiana found in south-west Cambodia’s Cardamom Mountain range is a largely unknown potentially at-risk species. We used line transects and camera traps to survey A. cambodiana in four protected areas in the Cardamom Mountains to estimate population densities. We also assessed their current distribution range and broad scale habitat changes from 1996 to 2016. We found A. cambodiana in evergreen and semi-evergreen forest at a density of 1.23 calling males/km2, and at altitudes above 400 m and where the slope was between 11 and 43o. From 1996 to 2016 A. cambodiana’s potential habitat decreased by 11%, whilst the total evergreen forest cover in the Cardamom Mountains decreased by 20%. A. cambodiana has a very restricted range within which the habitat has been fragmented. Compounded by human disturbance and development activities that negatively affect the species, we suggest a revision of its IUCN Red List status from ‘Least Concern’ to ‘Near Threatened’ as it partially meets a range of threatened Red List species criteria.

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Survival and extinction of breeding landbirds on San Cristóbal, a highly degraded island in the Galápagos

Bird Conservation International ◽

10.1017/s0959270919000285 ◽

2019 ◽

Vol 30 (3) ◽

pp. 381-395 ◽

Cited By ~ 2

Author(s):

MICHAEL DVORAK ◽

BIRGIT FESSL ◽

ERWIN NEMETH ◽

DAVID ANCHUNDIA ◽

JAVIER COTÍN ◽

...

Keyword(s):

Habitat Loss ◽

Large Scale ◽

Vegetation Change ◽

Bird Species ◽

Small Population ◽

Santa Cruz ◽

Present Evidence ◽

Point Counts ◽

Near Threatened ◽

Better Than

SummaryWe documented the consequences of large-scale habitat loss on a community of Galápagos native bird species on San Cristóbal island, based on point counts conducted between 2010 and 2017. Surprisingly, despite considerable habitat change and a variety of other threats, the landbirds of San Cristóbal have fared much better than on the neighbouring islands Floreana or Santa Cruz. While two species went extinct very soon after human colonisation, the majority have adapted well to subsequent vegetation change and habitat loss. The endemic San Cristóbal Mockingbird Mimus melanotis is more widespread than previously thought and its population seems to be stable since the 1980s. We thus propose a change in IUCN classification from ‘Endangered’ to ‘Near threatened’. We present evidence gained by interviewing locals which suggests that a small population of the Least Vermilion Flycatcher Pyrocephalus dubius, classified as ‘Extinct’ by BirdLife International, may have persisted until very recently. Although extensive searches in 2018 and 2019 were unsuccessful, the possibility remains that a few birds may have survived in remote parts of the island. Further searches that involve the general public and other interested parties are therefore deemed necessary.

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Current status of the threatened Dupont's lark Chersophilus duponti in Spain: overestimation, decline, and extinction of local populations

Oryx ◽

10.1017/s0030605305000165 ◽

2005 ◽

Vol 39 (1) ◽

pp. 90-94 ◽

Cited By ~ 33

Author(s):

José L. Tella ◽

Matthias Vögeli ◽

David Serrano ◽

Martina Carrete

Keyword(s):

Habitat Degradation ◽

Iucn Red List ◽

European Population ◽

Current Status ◽

Isolated Populations ◽

Local Populations ◽

Population Sizes ◽

Line Transects ◽

Dupont’S Lark

The European population of Dupont's lark Chersophilus duponti, restricted to Spanish steppe, was estimated to be 13,000 pairs in c. 50 populations in 1988. There is, however, recent evidence that this number was overestimated because of the previous use of line transects for estimating population sizes. In 2002–2004 we surveyed 34 previously known local populations in patches of variable size across half of its Spanish distribution. We found 13 (38%) local populations to be extinct, and a total of only 283–339 territories in 17 of the extant populations, seven of which held <5 territories. This census contrasts dramatically with the estimate of c. 3,000 pairs in the same populations in the 1980s. We estimate that the present Spanish population is c. 1,300 pairs. The discrepancy between this and earlier estimates is partly but not entirely due to previous overestimations. Habitat loss due to ploughing, and possibly habitat degradation and the resulting stochastic extinction of small and isolated populations, have contributed to the species' decline. Urgent research is needed to design and manage an adequate network of steppe patches that will ensure the long-term existence of this species. We recommend that Dupont's lark be categorized on the IUCN Red List as Endangered, both globally and nationally within Spain.

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