Research Article
Implications of changing species definitions for conservation purposes
- Stephen T. Garnett, Les Christidis
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- Published online by Cambridge University Press:
- 24 September 2007, pp. 187-195
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Concern has been expressed that failure to adopt phylogenetic or related species concepts will result in biodiversity loss. Here we describe how widespread adoption of such concepts may affect conservation administration and the social contract with elected governments that fund management of threatened species. We then review threatened species legislation, showing that most laws and international conventions avoid arguments over species' definitions altogether, thus negating arguments that such definitions should be changed to further species' conservation.
Severe declines of Eastern Imperial Eagle Aquila heliaca populations in the Baikal region, Russia: a modern and historical perspective
- Vitaliy V. Ryabtsev, Todd E. Katzner
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- Published online by Cambridge University Press:
- 24 September 2007, pp. 197-209
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The Eastern Imperial Eagle (Aquila heliaca), a vulnerable and declining species, is widely but sparsely distributed throughout its range. Because much of that range extends through the Russian-speaking world, relatively little on the species has been published in English. The world's easternmost population of Eastern Imperial Eagles, at Lake Baikal, Russia, is particularly well studied and, because of recent rapid population declines, is of great conservation concern. Here, using a data set covering more than 20 years evaluated in the context of historical accounts published in Russian, we assess recent severe declines in this population and the subsequent changes in its conservation status. In intensively surveyed areas near Lake Baikal, numbers of territories occupied by eagles have declined by 80–100% in the past 20–40 years. Likewise, throughout the entire region, the average number of known occupied and breeding territories were both more than 40% lower in 1998–1999 than they were in 1982–1983. These data suggest severe long-term declines in the population of Baikal's Imperial Eagles. Because we observed only limited decreases in reproductive output, our interpretation of the patterns in these data is that mortality of non-breeding birds (wintering adults and all pre-adults) is the most likely cause for this decline. Addressing the causes of this decline is critical to protect this severely threatened population from extirpation.
Восточный могильник (Aquila heliaca), уязвимый и сокращающийся в численности вид, широко, но разрозненно распространен по своему ареалу. В связи с тем, что большая часть его ареала находится в пределах русскоговорящей части мира, относительно мало опубликовано по этому виду на английском языке. Самая восточная группировка могильника находится в Прибайкалье. Она изучена особенно хорошо и из-за быстрого сокращения популяции вызывает особую тревогу и озабоченность природоохранников. Используя более чем >20 летние данные, рассмотренные в контексте исторических сведений опубликованных по-русски, мы оцениваем недавнее серьёзное сокращение этой популяции и последующие изменения в её природоохранном статусе. На территориях, находящихся под интенсивным обследованием в Прибайкалье, количество участков занятых орлами сократилось на 80–100% за последние 20–40 лет. Таким же образом, во всем регионе, среднее количество известных занятых территорий и гнездовых участков в 1998–1999 было на >40% меньше по сравнению с 1982–1983. Эти данные свидетельствуют о серьёзном долговременном сокращении прибайкальской популяции могильника. В связи с тем, что мы наблюдали лишь незначительное снижение результатов размножения, наша интерпретация модели по этим данным приводит к выводу, что смертность неразмножающихся птиц (зимующих взрослых и неполовозрелых птиц) является наиболее вероятной причиной этого сокращения. Выявление причин произошедшего падения численности очень важно для сохранения этой угрожаемой популяции от полного вымирания.
Are saltflats suitable supplementary nesting habitats for Malaysian Plovers Charadrius peronii threatened by beach habitat loss in Thailand?
- Maï Yasué, Allison Patterson, Philip Dearden
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- Published online by Cambridge University Press:
- 24 September 2007, pp. 211-223
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Resort development and coastal beach erosion have led to declines in beach breeding habitat for the near-threatened Malaysian Plover (Charadrius peronii) in the Gulf of Thailand. Semi-natural saltflats may provide supplementary nesting areas. We compared the environmental conditions, incubation behaviour and nesting success of plovers breeding on sandy beaches and saltflats in Thailand. In total we monitored 21 and nine nesting attempts in 2004 (beaches and saltflats, respectively) and 26 and 22 nesting attempts in 2005. Despite higher air temperatures in the saltflats (P < 0.0001), we detected no significant differences in nest attendance (P = 0.542 and P = 0.885 for 2004 and 2005, respectively), number of incubator changes between parents (P = 0.776 and P = 0.823) or number of parental nest departures (P = 0.087 and P = 0.712) during 120 incubation observations on 55 nests. There was also no difference in hatching success between beaches in 2004 (beach = 0.65, saltflat = 0.55; P = 0.692, n = 26) and 2005 (beach = 0.46, saltflat = 0.35; P = 0.539, n = 41). These results suggest that saltflats may provide nesting habitat for Malaysian Plovers and could help enhance overall hatching success rates by reducing nesting densities on beaches. Although there are few remaining intact saltflats in coastal Thailand, there are currently vast areas of abandoned tiger prawn aquaculture ponds that could be rehabilitated into saltflats at relatively low cost. Given the large area of disused aquaculture ponds throughout Thailand and South-East Asia and the substantial human pressure on coastal habitats, there could be considerable conservation benefits to the restoration of aquaculture ponds.
New information on the Critically Endangered Javanese Lapwing Vanellus macropterus, based mainly on unpublished notes by August Spennemann (c. 1878–1945)
- S (BAS) Van Balen, Vincent Nijman
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- Published online by Cambridge University Press:
- 24 September 2007, pp. 225-233
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In a manuscript written by August Spennemann in the 1930s, information is presented on display behaviour, vocalizations and habitat at two hitherto unknown localities of the Javanese Lapwing Vanellus (Hoplopterus) macropterus, a species last recorded in 1940. We provide a translation of the notes and give a summary of all information additional to what has already been published on the species. The Javanese Lapwing is historically known from two discrete areas on the island of Java: one in the west along the north coast, and one in the east along the south coast. Spennemann's observations, made in 1927 and 1928 at Poponcol and Tegallurung, represent the last documented sightings of the species along the north coast and are situated some 75 km east of the north coast's previous easternmost known locality, effectively doubling the species' known range in western Java. At this time, the Javanese Lapwing was observed daily, and unlike at most other localities from where the species is known, was common. Spennemann observed them in groups of up to six birds, the largest group size recorded. Some local movement or migration is suggested by its erratic occurrence and off-shore sightings.
Seasonal variation in hornbill abundance in a West African national park detected using analysis of acoustic recordings
- Hugo J. Rainey, Klaus Zuberbühler
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- Published online by Cambridge University Press:
- 24 September 2007, pp. 235-244
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Distance sampling, line transects and radio-tracking have been used previously to estimate population abundances and movements of hornbills. We used a large dataset of audio recordings made over 10 years to estimate seasonal variation in abundance of three species: Black-casqued Hornbill Ceratogymna atrata, Yellow-casqued Hornbill C. elata and Brown-cheeked Hornbill Bycanistes cylindricus, in Taï National Park, Côte d'Ivoire. The latter two species are Near Threatened. Recordings of hornbill wing-beats were used to control for potential seasonal variation in call production. Yellow- and Black-casqued Hornbill calls were 10 times as abundant from July to February as they were from March to June. Brown-cheeked Hornbills showed a similar trend, but less pronounced. From these data we concluded that large numbers of Yellow- and Black-casqued Hornbills had left the Taï National Park during this period. The significance of these findings is discussed in relation to the fragmentation and regeneration of the Upper Guinea forests and the relatively small size of the remaining forest habitat in the region.
Les taux d'abondance et de mouvement des populations de calaos étaient auparavant estimés par un échantillonnage et des analyses sur le logiciel Distance, des transects linéaires et des repérages télémétriques. Nous avons eu recours è un grand ensemble d'enregistrements audio effectués sur plus de 10 ans afin d'estimer la variation saisonniàre de l'abondance de trois espàces rencontrées dans le Parc National de Taï, en Côte d'Ivoire : le Grand Calao è Casque Noir Ceratogymna atrata, le Grand Calao è Casque Jaune Ceratogymna elata et le Calao è Joues Brunes Bycanistes cylindricus. Ces deux derniàres espàces sont aujourd'hui considérées comme presque menacées. Nous avons procédé è des enregistrements de battements d'ailes pour tester une potentielle variation saisonniàre de la production des cris. Les cris des Grands Calaos è Casque Jaune et è Casque Noir étaient dix fois plus abondants entre juillet et février qu'entre mars et juin. En revanche, les Calaos è Joues Brunes n'ont présenté qu'une petite variation du taux d'abondance entre ces deux périodes. D'apràs ces données, nous avons conclu qu'un grand nombre de Calaos è Casque Jaune et è Casque Noir quittent le Parc National de Taï entre mars et juin. La signification de ces découvertes est discutée en tenant compte de la fragmentation et de la régénération des forêts de Haute Guinée ainsi que de la dimension relativement petite de l'habitat forestier subsistant dans cette région.
Abundance, distribution and conservation of Rio Branco Antbird Cercomacra carbonaria and Hoary-throated Spinetail Synallaxis kollari
- Mariana M. Vale, J. Bruce Bell, Maria Alice S. Alves, Stuart L. Pimm
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- Published online by Cambridge University Press:
- 24 September 2007, pp. 245-257
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Cercomacra carbonaria and Synallaxis kollari are passerine birds endemic to the gallery forests of Roraima state in northernmost Brazil and adjacent Guyana. The IUCN Red List of Threatened Species lists both as Vulnerable but they have been removed from Brazil's list of threatened species because of data deficiency. They are poorly known, reflecting both Roraima state's distance from Brazil's main population centres and the inaccessibility of their habitat. In 2004 and 2005, we conducted bird surveys along the major rivers that provided previous sightings, and expanded records from only a handful to several dozens. We found C. carbonaria at 29% of the points surveyed, and estimated its local population density at approximately 80 individuals km−2 and total population size to exceed 15,000 individuals. The species has 723 km2 of available habitat, 8% of which is inside conservation units. We found S. kollari at 44% of the points surveyed, and estimated its local population density as approximately 60 individuals km−2, with an estimated total population size exceeding 5,000 individuals. It has 206 km2 of available habitat, none of which is inside conservation units. We recommend that C. carbonaria be down-listed on the IUCN Red List to the Near Threatened category, and that S. kollari be listed as Endangered. Both species live in areas vulnerable to habitat loss. We also recommend that both species re-enter the Brazilian list of threatened species and highlight the importance of indigenous reserves to their conservation.
Resumo
Cercomacra carbonaria e Synallaxis kollari são aves passeriformes das matas de galeria do Estado de Roraima em sua parte mais ao norte do Brasil e da Guiana adjacente. Ambas as espécies são catalogadas como “Vulneráveis” pela lista vermelha de espécies ameaçadas da IUCN, mas foram excluídas da lista de espécies ameaçadas do Brasil devido è insuficiência de dados. Estas espécies são pouco conhecidas, refletindo tanto a distância do Estado de Roraima dos principais centros urbanos quanto a inacessibilidade do seu hábitat. Em 2004 e 2005, realizamos censos de aves anteriormente avistadas ao longo de rios maiores, aumentando assim os registros de apenas alguns poucos números para diversas dezenas. Encontramos C. carbonaria em 29% dos pontos amostrados e estimamos sua densidade local em ∼80 indivíduos km−2 e o tamanho populacional total em mais de 15.000 indivíduos. A espécie possui 723 km2 de habitat disponível, 8% do qual está incluído em unidades de conservação. Encontramos S. kollari em 44% dos pontos amostrados e estimamos sua densidade populacional local em ∼60 indivíduos km−2, com uma estimativa de tamanho populacional total em mais de 5,000 indivíduos. Esta espécie tem 206 km2 de habitat disponível, nenhum dos quais incluído em unidades de conservação. Recomendamos que C. carbonaria seja rebaixada para a categoria ‘Quase Ameaçada’ e S. kollari categorizada como ‘Ameaçada’ na lista vermelha da IUCN. Ambas as espécies vivem em áreas vulneráveis em relação è perda de seu hábitat. Recomendamos, também, que ambas as espécies sejam re-incluídas na lista de espécies ameaçadas do Brasil, destacando a importância das reservas indígenas para a sua conservação.
Time budgets and habitat use of White-naped Cranes Grus vipio in the Ulz river valley, north-eastern Mongolia during the breeding season
- Ute Bradter, Sundev Gombobaatar, Chuluunbaatar Uuganbayar, Tracy E. Grazia, Klaus-Michael Exo
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- Published online by Cambridge University Press:
- 24 September 2007, pp. 259-271
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Habitat loss and degradation are critical threats for the globally threatened White-naped Crane Grus vipio. We estimated the size of the area used per day and the time budgets of parental and non-parental White-naped Crane pairs in north-eastern Mongolia during 2000 and 2001. Six parental crane pairs used an area of 11–155 ha per day. The maximum distance of a focal parental crane from the roosting-site was 3,030 m. Habitat conservation measures for breeding White-naped Cranes need to be targeted to within at least 3 km of the roosting-site or nest-site. Parental cranes spent 79.6 ± 4.8% of the daylight period foraging and had reduced preening and resting behaviour to 4.4 ± 1.9%. Pairs without juveniles showed a pronounced period of resting and preening behaviour during midday, which was absent in parental cranes. This indicates that parental cranes may be time-stressed. We conclude that increases in feeding-related activities (e.g. caused by a decrease in food availability) are likely to be at the expense of parental vigilance. Conversely, increases in vigilance (due to e.g. increased disturbance) may have a negative impact on feeding-related activities. Both increases can potentially negatively affect reproductive success in this Vulnerable species.
Exterior nest-boxes may negatively affect Barn Owl Tyto alba survival: an ecological trap
- Ákos Klein, Tibor Nagy, Tibor Csörgő, Róbert Mátics
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- Published online by Cambridge University Press:
- 24 September 2007, pp. 273-281
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Nest-site reduction has played a significant role in the decline of Barn Owl Tyto alba populations throughout Europe and North America. Techniques of nest-site augmentation, involving the provision of nest-boxes, have been widely used in a range of species of conservation concern, including falcons, eagles, parrots, owls and cavity-nesting ducks. A common method of Barn Owl conservation is the placement of nest-boxes on church towers. Despite the usefulness of nest-boxes, several studies have shown that there may be associated disadvantages and that nest-boxes may even act as ‘ecological traps’. The purpose of this research was to compare the survival rate of owlets hatched in nest-boxes with those hatched in the more “natural” environment of church towers. Survival time analysis elucidated that owlets developing in nest-boxes had significantly lower survival than those hatched in church towers. This difference was most obvious after the parent-dependent period of the life history. Surprisingly, the length of time from hatching to the onset of winter had no effect on the survival of the owlets, even though the accumulation of sufficient body reserves and acquisition of hunting experience are thought to be important in determining survival during the critical first winter of life. We propose possible causes for the negative effects of nest-boxes and recommend some modifications to the priorities of Barn Owl Action Plans, e.g. partial reopening of buildings instead of nest-box installation. This paper emphasizes the importance of considering revision of Species Action Plans in the case of other endangered species where conservation is based on nest-site supplement (e.g. hornbills, cavity-nesting seabirds, European Roller Coracias garrulus, Little Owl Athene noctua, Saker Falcon Falco cherrug, White Stork Ciconia ciconia).
The Chestnut-banded Plover is an overlooked globally Near Threatened Species
- Rob Simmons, Neil Baker, Rod Braby, Tim Dodman, Oliver Nasirwa, Stephanie Tyler, Wilferd Versfeld, Keith Wearne, Marius Wheeler
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- Published online by Cambridge University Press:
- 24 September 2007, pp. 283-293
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Species that show obvious population declines are relatively easy to categorize as globally threatened under IUCN Red List criteria. However, species whose populations are highly concentrated at a few inaccessible sites that are unprotected or habitat-threatened and then disperse are more difficult to pigeon-hole. Here we re-assess the conservation status of one such species – the Chestnut-banded Plover Charadrius pallidus – that occurs across Africa in specialized, inaccessible and arid habitat. Wetland bird counts from 1991 to the present allow us to determine a new world population estimate of about 17,830 birds. This allows us to determine a new 1% level and we identified only eight sites in southern and East Africa where these plovers congregate in numbers >1% when non-breeding. There are only five other sites that hold more than 100 birds, indicating that the species is not simply widely dispersed across suitable habitats. Simultaneous counts across southern and East Africa indicate that just three sites – Walvis Bay and Sandwich Harbour in Namibia and Lake Natron in Tanzania – can hold 87% of the world population during non-breeding periods. Since two of these sites are under threat from pollution, siltation and water abstraction, and the eight sites in total comprise just 30% of the area criteria set by IUCN, the bird meets one of the two qualifiers for globally Vulnerable status. Despite this, we cannot detect any long-term declines in population size, partly because of wide variations in population numbers over decadal time periods (itself an IUCN qualifier). It is clear that this bird should move from its present Least Concern status to Near Threatened and conservation measures be enacted at two of the top three sites – Walvis Bay and Lake Natron.