No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
An extinct species of tooth-billed pigeon (Didunculus) from the Kingdom of Tonga, and the concept of endemism in insular landbirds
Journal of Zoology
Abstract
The tooth-billed pigeon Didunculus strigirostris lives on three islands in Western (Independent) Samoa. A larger, extinct species, Didunculus placopedetes, is described from bones recovered in late Quaternary cave deposits on 'Eua, Kingdom of Tonga. Also referred to D. placopedetes are bones from archaeological sites on the larger Tongan island of Tongatapu and the smaller, lower islands of Lifuka, Ha'ano, 'Uiha and Ha'afeva. As with so many other landbirds in Polynesia, the extinction of D. placopedetes occurred since the arrival of people and presumably was due to human impact. The peopling of Tonga is why the genus Didunculus is considered to be endemic to Samoa. The biogeographic implications of the new data on Didunculus are not unique; human activities have reduced or eliminated the natural range of nearly every genus and species group of Polynesian landbird. The reduced ranges of surviving taxa have created a situation (herein called ‘pseudo-endemism’) where a taxon that seems today to be endemic to a restricted area (often one or two islands) was much more widespread at first human arrival. As the prehistoric record of insular birds improves in the Pacific and elsewhere, the list of pseudo-endemic taxa will continue to grow.
... . Because of the absence of suitable fossil deposits on many islands, often the only source of data for these extinctions is in the archaeological deposits of the first human colonizers, as detailed by Steadman (2006a). Often more than 50% of the original avian diversity became extinct, with endemic flightless and large species suffering the most losses (Steadman 2006a). ...
... . Because of the absence of suitable fossil deposits on many islands, often the only source of data for these extinctions is in the archaeological deposits of the first human colonizers, as detailed by Steadman (2006a). Often more than 50% of the original avian diversity became extinct, with endemic flightless and large species suffering the most losses (Steadman 2006a). In total, Steadman (2006a:409) estimated that between 820 and 1,960 species of birds have become extinct in the Pacific, with the uncertainty mainly due to how rails might be estimated. ...
... Vanuatu has a diverse avifauna of minimally 62 species of land birds, including six extinct taxa (Doughty et al. 1999, Steadman 2006a. The fauna has relatively low levels of endemism, with only 11 species, of which five are extinct, listed by Steadman (2006a). ...
The avifauna of the Teouma archaeological site on Efate in Vanuatu is described. It derives from the Lapita levels (3,000 – 2,800 ybp) and immediately overlying middens extending to ~2,500 ybp. A total of 30 bird species is represented in the 1,714 identified specimens. Twelve species are new records for the island, which, added to previous records, indicates that minimally 39 land birds exclusive of passerines were in the original avifauna. Three-fourths of the 12 newly recorded species appear to have become extinct by the end of Lapita times, 2,800 ybp. The avifauna is dominated by eight species of columbids (47.5% Minimum Number Individuals [MNI ]) including a large extinct toothbilled pigeon, Didunculus placopedetes from Tonga, and a giant Ducula sp. cf. D. goliath from New Caledonia. Seabirds are rare despite the coastal location of the site. Fowl are important contributors to the Teouma avifauna, with the human introduced
Red Junglefowl Gallus gallus accounting for 15% MNI and present in all sampled layers. There are two species of megapodes (~10% of MNI ), with the extant Vanuatu Megapode Megapodius layardi most abundant and represented at all levels in the deposits. A substantially larger extinct megapode, Mwalau walterlinii, n. gen., n. sp., is present only in the Lapita midden area, where it is relatively rare. This extinct species was larger than all extant megapodes but smaller than the extinct Progura gallinacea from Australia, with proportions most similar to those of Alectura, and was a volant bird. The remaining significant faunal component is rails, with four species present, of which Porphyrio melanotus was the most abundant. Rare but notable records include an undescribed large rail; a parrot, Eclectus sp. cf. E. infectus; a hornbill, Rhyticeros sp. cf. R. plicatus; and a
coucal, Centropus sp. indet., all conservatively considered likely to be conspecific with known taxa elsewhere in Melanesia.
... It is historically recorded from the islands of Savai'i (1,820 km 2 ), Upolu (1,110 km 2 ), Nu'utele (1.2 km 2 ), and Nu'ulua (0.2 km 2 ) in the Independent State of Samoa (Collar 2015), and is also known from a prehistoric archaeological assemblage on Ofu Island, American Samoa (Weisler et al. 2016). It is the only living representative of the genus Didunculus following prehistoric extinction of the Tongan species D. placopedetes (Steadman 2006b) and an unnamed species from Vanuatu (Worthy et al. 2015). Although historical abundance is uncertain, the Manumea is thought to have declined by over 90% since the 1980s due to invasive rats and cats, hunting, and habitat loss from human activities and cyclones; it is listed as Critically Endangered by the International Union for Conservation of Nature (IUCN), with only a tiny remnant population likely to survive (Beichle 1987;BirdLife International 2024;Collar 2015;Serra 2017;Serra et al. 2018). ...
... Threatened species often become restricted to ecologically marginal high-elevation refugia as populations decline (Fisher 2011;Turvey et al. 2015), raising the possibility that models which only include recent Manumea records might show more restricted niche predictions compared with models also containing older records. Indeed, Steadman (2006b) suggested that Manumea survived on Samoa but died out on Tonga because Savai'i and Upolu are larger, higher and steeper islands. However, this possibility is contradicted by the relatively high spatial congruence between our visual reduced model (historical and recent visual records) and our visual combined model (recent-only visual records), and the negative correlation and low percentage contribution of elevation across our models, providing little evidence for elevational change in Manumea records over the past century. ...
Evidence-based conservation can be hindered by limited field data, but historical archives have the potential to provide unique insights into conservation-relevant parameters, such as identification of suitable habitat for threatened species. The Manumea or Tooth-billed Pigeon Didunculus strigirostris has declined on Samoa and only a tiny remnant population still persists, and a key first step for conservation is to locate surviving birds. Numerous Manumea records are available from the nineteenth century onwards, and we used historical and modern records to generate a series of species distribution models to predict the distribution of suitable habitat across Samoa to guide new field searches. Manumea distribution is closely associated with forest cover or its proxies. Preferred Manumea food plants are suggested to be low-elevation trees, but elevation provides relatively low percentage contribution in most models, thus not excluding the possibility that Manumea might occur at high elevations. There is also little evidence for elevational change in records over the past century. Models based on visual versus acoustic records exhibit differences in predicted habitat suitability, suggesting that some purported acoustic records might not actually represent Manumea calls. Field searches should target areas representing high habitat suitability across all models, notably the forested central axis of Upolu.
... Elsewhere in the Pacific, often up to half the fossil species were found to be extinct (Steadman 2006a), as in the Marquesas (Steadman 1989a;Steadman and Rolett 1996), Easter Island (Steadman 1995), Henderson Island (Wragg and Weisler 1994;Wragg and Worthy 2006;Wragg 2003, 2008), Society Islands (Steadman 1989a), Samoa (Steadman 1994), and on the Tongan and Cook Island groups (Steadman 1989a(Steadman , 1993(Steadman , 1995. Among the extinct taxa are many species of rails, megapodes, columbids and parrots (Balouet and Olson 1987;Kirchman and Steadman 2005, 2006a, 2006bSteadman 1987Steadman , 1989bSteadman , 1992Steadman , 2006aSteadman , 2006bSteadman , 2006cSteadman and Zarriello 1987;Wragg and Worthy 2006;Wragg 2003, 2008). A similar history of extinction has also been found in New Caledonia (Balouet and Olson 1989) and there are indications of them in Micronesia (Steadman and Intoh 1994;Steadman 2006a). ...
... Steadman (1993Steadman ( , 1997 reported a new species of Didunculus from two caves on 'Eua. It has recently been named (Steadman 2006c). ...
... In recurrent cases across the breadth of the Pacific, up to half the birds are extinct (Steadman 2006a) -for example, extinct-bird remains have been found in New Caledonia (Balouet and Olson 1989), Fiji (Worthy 2000(Worthy , 2001, the Tongan and Cook Island groups (Steadman 1989a(Steadman , 1993(Steadman , 1995, Samoa (Steadman 1994), Niue (Steadman et al. 2000), Society Islands (Steadman 1989a), Marquesas (Steadman 1989a;Steadman and Rolett 1996), Hawaii Olson and James 1991), and Easter Island (Steadman 1995). Among the extinct taxa are many species of columbids (Balouet andOlson 1987, 1989;Steadman 1989aSteadman , 1989bSteadman , 1992Steadman , 1997Steadman , 2006aSteadman , 2006bWorthy 2001;Worthy and Wragg 2003;Wragg and Worthy 2006). ...
... The fossil has a distinct elongate fossa immediately distad of the humeral facet on the lateral facies. This feature, noted by Steadman (2006b), is shared with the Pacific columbids Didunculus, Gallicolumba, Goura and Caloenas, thus differentiating it from other Pacific columbids including Ptilinopus, Ducula and Columba. Steadman (2006) noted that a convex humero-ventral portion of the corpus coracoideum, which we interpret as the ventral facies adjacent to the humeral facet and opposite the scapular cotyla, was a feature of Didunculus. ...
... The osteology of the columbid coracoid was the subject of a detailed description (Martin 1904 ), but this work outlined few intergeneric distinguishing features. More recently, Worthy (2001) detailed coracoid characters useful for generic identification, and these were expanded by Wragg (2003, 2008) and by Steadman (2006). Our comparisons were mainly restricted to taxa in the Australasian–Pacific region; because of geographic separa ...
... ve to the ventral facies, rather than a single pit or groove. These taxa form a well-supported clade based on robust and diverse molecular data (Pereira et al. 2007 ). These apomorphies augment the identification of a characteristic sternal morphology (Boles 1999); however, that character is ambiguous, because a similar state is shared with Treron. Steadman (2006) described columbids as the most taxonomically diverse family of land birds in the Pacific Ocean region, but until now the antiquity of such radiations in the region has been unknown. Three closely related species in the genus Hemiphaga, all of which inhabit forest, are currently recognized: H. novaeseelandiae from mainland New Zealand a ...
Describimos un nuevo género y especie de paloma (Columbiformes) de un único coracoides de la fauna St Bathans de Nueva Zelandia (16–19 millones de años antes del presente). Es la primera especie de paloma descrita de depósitos pre-Pliocénicos en Australasia. Dos apomorfías identifican el fósil como perteneciente al grupo ptilinopino de las palomas fruteras, entre las cuales es más parecida a Hemiphaga, la gran paloma frutera actualmente endémica del área biogeográfica de Nueva Zelandia. Esto revela que el linaje de Hemiphaga ha estado en Nueva Zelandia desde el Mioceno Temprano, lo cual avala estimados recientes de fechas de divergencia para Hemiphaga y su taxón hermano moderno (Lopholaimus) basados en datos moleculares.
... If so, their discovery in the modern faunas or subfossil records of Fiji, Tonga, and on other islands of the Vanuatu and Samoan archipelagos might be expected in the future. For example, the current geographic restriction of P. fundatus to the small outlying Banks and Torres island groups of Vanuatu (Flannery, 1995) seems likely to be a relictual distribution indicative of ''pseudoendemism'' in that ar-chipelago (Steadman, 1997(Steadman, , 2006a. In this vein, we note with interest that Hickey (2007) discussed a small, dark-colored, inflorescenceeating Pteropus observed on the large island of Malekula in Vanuatu. ...
... With the advent in recent decades of rigorous zooarchaeological excavations in Pacific archipelagos, and the resulting systematic studies of osteological remains, it is now well established that both insular extirpations and global extinctions of vertebrate species have been widespread and severe throughout the region since the first arrivals of human settlers to many island groups in recent millennia (e.g., Steadman, 1993Steadman, , 1995Steadman, , 1997Steadman, , 2006aSteadman, , 2006bSteadman and Kirch, 1990;Pregill, 1993;Pregill and Dye, 1989;Balouet and Buffetout, 1987;Mead et al., 2002;Molnar et al., 2002;Helgen, 2004b). Documented prehistoric vertebrate extinctions in the Pacific primarily concern birds, lizards, and land crocodiles; relatively few examples concerning mammals are known (Flannery, 1995). ...
Two new species of flying foxes (genus Pteropus) from the Samoan archipelago are described on the basis of modern museum specimens collected in the mid-19th century. A medium-sized species (P. allenorum, n. sp.) is introduced from the island of Upolu (Independent Samoa), based on a specimen collected in 1856 and deposited in the Academy of Natural Sciences of Philadelphia. It has not been collected again, and we regard it as almost certainly extinct. This species is smaller bodied and has much smaller teeth than both extant congeners recorded in the contemporary fauna of Samoa (Pteropus samoensis and P. tonganus). The closest relative of this new species may be Pteropus fundatus of northern Vanuatu. The disjunct historical distribution of these two small- toothed flying foxes (in Vanuatu and Samoa) suggests that similar species may have been more extensively distributed in the remote Pacific in the recent past. Another species, a very large flying fox with large teeth (P. coxi, n. sp.), is described from two skulls collected in Samoa in 1839-1841 during the U.S. Exploring Expedition; it too has not been collected since. This robust species resembles Pteropus samoensis and Pteropus anetianus of Vanuatu in craniodental conformation but is larger than other Polynesian Pteropus, and in some features it is ecomorphologically convergent on the Pacific monkey-faced bats (the pteropodid genera Pteralopex and Mirimiri). On the basis of eyewitness reports from the early 1980s, it is possible that this species survived until recent decades, or is still extant. These two new Samoan species join Pteropus tokudae of Guam, P. pilosus of Palau, P. subniger of the Mascarenes, and P. brunneus of coastal north-eastern Australia as flying
... The osteology of the columbid coracoid was the subject of a detailed description (Martin 1904), but this work outlined few intergeneric distinguishing features. More recently, Worthy (2001) detailed coracoid characters useful for generic identification, and these were expanded by Worthy andWragg (2003, 2008) and by Steadman (2006). Our comparisons were mainly restricted to taxa in the Australasian-Pacific region; because of geographic separation, taxa outside this region were considered unlikely relatives. ...
... These apomorphies augment the identification of a characteristic sternal morphology (Boles 1999); however, that character is ambiguous, because a similar state is shared with Treron. Steadman (2006) described columbids as the most taxonomically diverse family of land birds in the Pacific Ocean region, but until now the antiquity of such radiations in the region has been unknown. Three closely related species in the genus Hemiphaga, all of which inhabit forest, are currently recognized: H. novaeseelandiae from mainland New Zealand and, formerly, the Kermadec (Goodwin 1967, Pereira et al. 2007. ...
We describe a new genus and species of pigeon (Columbiformes) from a single coracoid from the St Bathans Fauna of New Zealand (16-19 mya). It is the first columbid species described from pre-Pliocene deposits in Australasia. Two apomorphies identify the fossil as belonging to the ptilinopine group of fruit pigeons, among which it is most similar to Hemiphaga, the large fruit pigeon currently endemic to the New Zealand biogeographic area. This reveals that the Hemiphaga lineage has been in New Zealand since the Early Miocene, which supports recent divergence-date estimates for Hemiphaga and its modern sister taxon (Lopholaimus) based on molecular data. Received 26 November 2008, accepted 27 March 2009.
... strigirostris, parrot Prosopeia sp., and lorikeet ?Charmosyna amabilis. Didunculus is otherwise known from Samoa (the living D. strigirostris) and Tonga (the extinct D. placopedetes; Steadman, 2006a). Prosopeia and Charmosyna exist on large islands of western Fiji (the living P. personta, P. tabuensis, and C. amabilis), but nowhere in the Lau Group. ...
We identified nearly 1000 bones of reptiles and birds from 20 prehistoric sites in caves and rockshelters on four islands (Lakeba, Nayau, Aiwa Levu, and Aiwa Lailai) in the Lau Group of Fiji. The bones are Late Holocene in age (ca. 2800 to 200 years old) and are contemporaneous with prehistoric human habitation of the islands. They represent 32 species (7 reptiles, 25 non-passerine landbirds). Six of the seven taxa of squamate reptiles recovered from the prehistoric sites are indigenous to the Lau Group, including an undescribed and presumably extinct species of gekkonid lizard. While the Lau islands have never been surveyed comprehensively for modern squamate reptiles, six other species of lizards known to occur in Lau today are not represented with certainty in any of the bone deposits (the geckos Hemidactylus frenatus and Lepidodactylus lugubris, and skinks Emoia cyanura, E. impar, Cryptoblepharus eximius, and Lipinia noctua). Except for C. eximius, these synthropic and not necessarily native species are widespread on Pacific islands, with much or all of their dispersal being due to human agency. For landbirds, the prehistoric bones increase the species richness values from 21 to 29 species on Lakeba, from 17 to 19 species on Nayau, from 18 to 26 on Aiwa Levu, and from 16 to 17 on Aiwa Lailai. The extinct species of birds consist of two megapodes (Megapodius alimentum, M. amissus), two flightless rails (Gallirallus undescribed sp., Porzana undescribed sp.), and a pigeon (Ducula lakeba). Three living species of birds recorded pre-historically, but that no longer occur on these islands, are characteristic of freshwater habitats: the heron Butorides striatus and two volant rails, Porzana tabuensis and Poliolimnas cinereus. Three other extant species recorded from bones on Lakeba, but that no longer inhabit that island or any others in Lau, are the pigeon Didunculus cf. strigirostris, parrot Prosopeia sp., and lorikeet ?Charmosyna amabilis. Much of the inter-island differences in total species richness of birds (modern + prehistoric) is probably due to uneven sampling of prehistoric bones, which are both older (on average) and more abundant on Lakeba and Aiwa Levu than on the other two islands. Reconstructing the composition of the reptile and bird communities as they existed at first human contact demonstrates the unappreciated species richness of very small islands, a concept of interest to biogeographers and conservation biologists.
... While its distinctive bill shape in particular, as well as its size and insular isolation provide superficial reminders of the Dodo Raphus cucullatus [formerly Didus ineptus], it recently has been demonstrated that its affinities lie close to the Dodo, and indeed it is one of the Dodo's nearest living relatives (Shapiro et al. 2002). Also like the Dodo, it had very closely related, but now extinct, relatives on nearby island groups, as demonstrated by the recent discovery of a Tongan Tooth-billed Pigeon D. placopedetes, which was up to 40% larger than Samoan birds (Steadman 2006;Hume & Walters 2012: 156;Hume 2017: 179), and another, as yet unnamed, of similar size to Samoan birds, from Fiji (Worthy & Clark 2009: 251); both having long ago succumbed to the predations of man and other introduced mammals and this may yet be the fate of D. strigirostris (Collar 2015, Baumann & Beichle 2020). ...
... The new species of Gallirallus vekamatolu Kirchman & Steadman, 2005 was described from prehuman sites on 'Eua (Kirchman & Steadman, 2005), but 188 rail bones from seven archaeological sites in the Ha'apai Group were, except for two, identified as Gallirallus [Hypotaenidia] philippensis (Linnaeus, 1766). In 2006, a new species of the tooth-billed pigeon (Didunculus placopedetes Steadman, 2006) was described from faunas from 'Eua, Tongatapu and the Ha'apai Group (Steadman, 2006b), and a new large parrot (Eclectus infectus Steadman, 2006) was named from various sites (Steadman, 2006c). Steadman's (2006a) synthetic volume incorporates a summary of these avian faunas, although the last-mentioned rail, parrot and pigeon taxa were listed as undescribed species therein. ...
Avifaunas derived from Lapita archaeological sites excavated between 2004 and 2014 from four sites in the Vava'u Group and two on Tongatapu, Kingdom of Tonga are described, revealing birds encountered by the first human arrivals. A total of 741 identifiable bones revealed 24 avian taxa, among which terrestrial birds, especially rails, pigeons and parrots, were the most abundant. At a minimum, eight taxa, or 50% of the original non-passerine land bird diversity in the sample, are globally extinct. These include two megapodes (Megapodius alimentum and a larger unnamed megapode), three pigeons (a large Caloenas sp. indet., Didunculus placopedetes and Ducula shutleri sp. nov.), two rails (Hypotaenidia vavauensis sp. nov. and an unnamed one) and the parrot Eclectus infectus. The rail H. vavauensis was restricted to Vava'u and was flightless, with reduced wings, and larger than Hypotaenidia woodfordi of the Solomons, the largest congener hitherto found in the Pacific. The pigeon Du. shutleri was volant, but was the largest species in its genus and was widespread in the Kingdom. The evolution of Tongan avifaunas is related to varying ages (Pliocene to Pleistocene) of the island groups, where geological youth apparently precluded true giantism in the fauna.
... Elsewhere in the Pacific, often up to half the fossil species were found to be extinct (Steadman 2006a), as in the Marquesas (Steadman 1989a;Steadman and Rolett 1996), Easter Island (Steadman 1995), Henderson Island (Wragg and Weisler 1994;Wragg and Worthy 2006;Wragg 2003, 2008), Society Islands (Steadman 1989a), Samoa (Steadman 1994), and on the Tongan and Cook Island groups (Steadman 1989a(Steadman , 1993(Steadman , 1995. Among the extinct taxa are many species of rails, megapodes, columbids and parrots (Balouet and Olson 1987;Kirchman and Steadman 2005, 2006a, 2006bSteadman 1987Steadman , 1989bSteadman , 1992Steadman , 2006aSteadman , 2006bSteadman , 2006cSteadman and Zarriello 1987;Wragg and Worthy 2006;Wragg 2003, 2008). A similar history of extinction has also been found in New Caledonia (Balouet and Olson 1989) and there are indications of them in Micronesia (Steadman and Intoh 1994;Steadman 2006a). ...
... Known or presumed relatives live or lived mainly on islands from Mascarene Islands in the west to Samoan Islands in the east (Gibbs et al., 2001;Worthy, 2001). These islands, mainly of volcanic origin, are geologically unstable and that could have caused extinctions among close relatives (Heupink et al., 2014), in addition to the massive prehistoric and historic human-caused extinctions that have affected many landbirds, including pigeons, and are still and may remain largely undocumented (Steadman, 2006(Steadman, , 1995. Alternatively, it is also plausible that the Goura lineage originated and perhaps diversified in Australia before dispersing across to New Guinea, and then went extinct in Australia (Schodde, 2006); the absence of any known close relative of Goura in Australia and the lack of fossil data does not allow us to formally test the hypothesis, however. ...
Assessing the relative contributions of immigration and diversification into the buildup of species diversity is key to understanding the role of historical processes in driving biogeographical and diversification patterns in species-rich regions. Here, we investigated how colonization, in situ speciation, and extinction history may have generated the present-day distribution and diversity of Goura crowned pigeons (Columbidae), a group of large forest-dwelling pigeons comprising four recognized species that are all endemic to New Guinea. We used a comprehensive geographical and taxonomic sampling based mostly on historical museum samples, and shallow shotgun sequencing, to generate complete mitogenomes, nuclear ribosomal clusters and independent nuclear conserved DNA elements. We used these datasets independently to reconstruct molecular phylogenies. Divergence time estimates were obtained using mitochondrial data only. All analyses revealed similar genetic divisions within the genus Goura and recovered as monophyletic groups the four species currently recognized, providing support for recent taxonomic changes based on differences in plumage characters. These four species are grouped into two pairs of strongly supported sister species, which were previously not recognized as being close relatives: Goura sclaterii with Goura cristata, and Goura victoria with Goura scheepmakeri. While the geographical origin of the Goura lineage remains elusive, the crown age of 5.73 Ma is consistent with present-day species diversity being the result of a recent diversification within New Guinea. Although the orogeny of New Guinea's central cordillera must have played a role in driving diversification in Goura, cross-barrier dispersal seems more likely than vicariance to explain the speciation events having led to the four current species. Our results also have important conservation implications. Future assessments of the conservation status of Goura species should consider threat levels following the taxonomic revision proposed by del Hoyo and Collar (HBW and BirdLife International illustrated checklist of the birds of the world 1: non-passerines, 2014), which we show to be fully supported by genomic data. In particular, by distinguishing G. sclaterii from G. scheepmakeri seems to be particularly relevant.
... The poor available Quaternary record for most southeast Asian islands continues to hinder rigorous comparison of inter-island faunal evolution and dispersal across this biogeographically complex region, and it is possible that taxa currently represented in modern or Quaternary faunas from single Wallacean islands may have had much wider former distributions which have not yet been adequately sampled (cf. [58]). Future work on Quaternary microvertebrate faunas from Sumba may also provide important novel insights into regional biogeography. ...
Historical patterns of diversity, biogeography and faunal turnover remain poorly understood for Wallacea, the biologically and geologically complex island region between the Asian and Australian continental shelves. A distinctive Quaternary vertebrate fauna containing the small-bodied hominin Homo floresiensis, pygmy Stegodon proboscideans, varanids and giant murids has been described from Flores, but Quaternary faunas are poorly known from most other Lesser Sunda Islands. We report the discovery of extensive new fossil vertebrate collections from Pleistocene and Holocene deposits on Sumba, a large Wallacean island situated less than 50 km south of Flores. A fossil assemblage recovered from a Pleistocene deposit at Lewapaku in the interior highlands of Sumba, which may be close to 1 million years old, contains a series of skeletal elements of a very small Stegodon referable to S. sumbaensis, a tooth attributable to Varanus komodoensis, and fragmentary remains of unidentified giant murids. Holocene cave deposits at Mahaniwa dated to approximately 2000–3500 BP yielded extensive material of two new genera of endemic large-bodied murids, as well as fossils of an extinct frugivorous varanid. This new baseline for reconstructing Wallacean faunal histories reveals that Sumba's Quaternary vertebrate fauna, although phylogenetically distinctive, was comparable in diversity and composition to the Quaternary fauna of Flores, suggesting that similar assemblages may have characterized Quaternary terrestrial ecosystems on many or all of the larger Lesser Sunda Islands.
... There is therefore increasing awareness of the need to integrate historical archives into conservation research and environmental management, to provide novel insights into patterns of past extinction and ecosystem structure that are unavailable from short-term ecological studies (Bonebrake et al., 2010;Rick & Lockwood, 2013;Davies et al., 2014). In particular, due to past humancaused biodiversity loss, observed modern-day geographical ranges of many formerly widespread species represent reduced 'pseudo-endemic' distributions lacking a true evolutionary or ecological basis, following extirpation across other parts of a historical range (Steadman, 2006;Turvey, 2009). These remnant subpopulations often persist in peripheral 'refugia' that may represent areas of reduced anthropogenic extinction pressure rather than optimal habitat (McShea et al., 1999;Channell & Lomolino, 2000). ...
Aim
To clarify the post‐glacial biogeography of the Annamite and eastern Chinese ungulate faunas, and determine whether current understanding of Asian mammalian biogeography is biased by pseudo‐extinctions and pseudo‐endemism associated with a historical extinction filter.
Location
Modern‐day specimens of giant muntjac ( Muntiacus vuquangensis ) from the Annamite Mountains of Laos and Vietnam were compared with zooarchaeological specimens of extinct giant muntjac ( M. gigas ) from eastern China, and with a reference sample of northern red muntjac ( M. vaginalis ) from China, Southeast Asia and South Asia.
Methods
We analysed a data set of antler measurements using Multivariate analyses of variance ( MANOVA s), principal component analyses ( PCA s) and scaling relationships, to quantify morphometric variation between extinct and living giant muntjacs in relation to variation shown by a different sympatric large‐bodied muntjac species. We also attempted ancient biomolecule analysis of Holocene samples from China.
Results
Although the combined giant muntjac sample can be differentiated from the reference red muntjac sample in all of our multivariate morphometric analyses, no significant differences are shown between extinct and living giant muntjacs using any analyses, matching the pattern seen when comparing conspecific red muntjac samples from across the same geographical region.
Main conclusions
We find no support for recognizing extinct and living giant muntjacs as distinct taxa, and post‐glacial populations from China and the Annamites should probably all be referred to M. gigas . The likely conspecificity of giant muntjacs across Eastern and Southeast Asia demonstrates that current‐day Asian mammalian biogeography has been shaped by an extinction filter and challenges the idea that the Annamite region represents a cradle of evolution; instead, it may represent a refuge of diversity for some taxa, preserving remnant pseudo‐endemic populations of species that have been extirpated across other parts of their former ranges.
... Geographical range contraction is a fundamental characteristic of species population decline (Mace et al., 2008), with remnant subpopulations often persisting in peripheral 'refugia' after extirpation across other parts of a historical range (Lomolino & Channell, 1995;McShea et al., 1999;Channell & Lomolino, 2000a,b). As a result of past humancaused biodiversity loss, modern-day ranges of many formerly widespread species represent reduced 'pseudo-endemic' distributions lacking a true evolutionary or ecological basis (Steadman, 2006;Turvey, 2009). Island birds in particular have experienced high levels of recent population extinction, with over 50% of extant procellariiform (albatross, petrel and shearwater) species having lost populations during the Holocene (Scofield, 2009). ...
Aim
To determine the taxonomic identity of zooarchaeological gadfly petrel ( Pterodroma ) specimens from northern Europe, in order to investigate whether an unknown, now‐extinct Pterodroma species formerly occurred in this region, or whether extant north‐east Atlantic gadfly petrel populations now restricted to the Macaronesian Islands formerly had a much wider Holocene distribution.
Location
Zooarchaeological Pterodroma material from the Hebrides, Scotland, was compared with modern‐day material from the Madeira and Cape Verde archipelagos (Macaronesia) and a global Pterodroma sample.
Methods
We employed techniques for ancient DNA analysis to amplify mitochondrial cytochrome b sequence data from an Iron Age Scottish Pterodroma specimen. Bayesian phylogenetic analyses were applied to assess the phylogenetic relationship between these ancient sequence data and extant Pterodroma taxa.
Results
The Scottish Pterodroma sample is phylogenetically distinct from living Macaronesian populations and from all other extant Pterodroma taxa. Although it is phylogenetically placed outside any single Macaronesian taxon, it is most closely related to the P. feae – deserta complex, and the level of sequence divergence between the Scottish Pterodroma and Macaronesian populations is lower than that observed between any two extant global Pterodroma taxa. The extinct north Atlantic gadfly petrels are therefore not distinct at the species level from these surviving populations, and instead form part of the young evolutionary radiation represented today by recently divergent Pterodroma populations on Bugio and Cape Verde, which can all be interpreted as conspecific.
Main conclusions
Our results suggest that surviving Macaronesian P . feae – deserta populations represent the final remnant of a wider Holocene distribution of this species complex, with the Madeira and Cape Verde archipelagos constituting the final sanctuary of Pterodroma in the north Atlantic following late Holocene extirpation of more northerly colonies possibly associated with human‐mediated invasive mammal introduction across northern Europe. Macaronesia may therefore constitute a ‘museum’ of diversity rather than a ‘cradle’ of evolution for Atlantic Pterodroma .
... Elsewhere in the Pacific, often up to half the fossil species were found to be extinct (Steadman 2006a), as in the Marquesas (Steadman 1989a; Steadman and Rolett 1996), Easter Island (Steadman 1995), Henderson Island (Wragg and Weisler 1994; Wragg and Worthy 2006; Wragg 2003, 2008), Society Islands (Steadman 1989a), Samoa (Steadman 1994), and on the Tongan and Cook Island groups (Steadman 1989aSteadman , 1993Steadman , 1995). Among the extinct taxa are many species of rails, megapodes, columbids and parrots (Balouet and Olson 1987; Kirchman and Steadman 2005, 2006a, 2006b Steadman 1987 Steadman , 1989b Steadman , 1992 Steadman , 2006a Steadman , 2006b Steadman , 2006c; Steadman and Zarriello 1987; Wragg and Worthy 2006; Wragg 2003, 2008). A similar history of extinction has also been found in New Caledonia (Balouet and Olson 1989) and there are indications of them in Micronesia (Steadman and Intoh 1994; Steadman 2006a). ...
... Steadman (1993Steadman ( , 1997 reported a new species of Didunculus from two caves on 'Eua. It has recently been named (Steadman 2006c). ...
... The fossil has a distinct elongate fossa immediately distad of the humeral facet on the lateral facies. This feature, noted by Steadman (2006b), is shared with the Pacific columbids Didunculus, Gallicolumba, Goura and Caloenas, thus differentiating it from other Pacific columbids including Ptilinopus, Ducula and Columba. Steadman (2006) noted that a convex humero-ventral portion of the corpus coracoideum, which we interpret as the ventral facies adjacent to the humeral facet and opposite the scapular cotyla, was a feature of Didunculus. ...
In 1991–1992, the large multidisciplinary Sir Peter Scott Commemorative Expedition to the Pitcairn Islands (Spencer and Benton 1995) included extensive archaeological and some palaeontological investigations (Weisler 1994, 1995; Wragg 1995a, b; Wragg and Weisler 1994). During these investigations, some 42 one metre square test pits were excavated in 11 archaeological and one natural site, resulting in a collection of some 42,213 bird bones (Wragg 1995a). Among four extinct land birds, Wragg and Weisler (1994) and Wragg (1995a) listed Columbidae n. gen et n. sp., Ducula n. sp., and Gallicolumba n. sp.. Steadman (1997, 2006a) continued to list Ducula aurorae and D. galeata from Henderson Island, while admitting that the
taxonomy of the extinct columbids was unresolved. Subsequently, Worthy and Wragg (2003) have described G. leonpascoi, and Wragg and Worthy (2006) Ducula harrisoni. It is the purpose of the present contribution to describe the new genus and species Wragg and Weisler (1994) revealed.
The Dodo and its extinct sister species, the Solitaire, are iconic exemplars of the destructive capabilities of humanity. These secondarily terrestrial columbids became extinct within a century of their first encounter with humanity. Their rapid extinction, with little material retained in natural history collections, led 18th and some early 19th century naturalists to believe that these aberrant birds were mythological. This meant that the nomenclatural publications in which their scientific nomina were established were based on accounts written before the species became extinct. As such, no type specimens were designated for either the Dodo or the Solitaire. Our in-depth historical overview of both species and associated family-group nomina found that the nominal authority of the Dodo-based family group is not what is reported in the literature. Moreover, our detailed review of the family-group nomina based on columbid genera ensures that the current columbid family-group systematization is valid. Changing nomenclatural norms between the 19th and 20th centuries had a profound impact on Dodo nomenclature; so much so that the Dodo is an example of how pervasive nomenclatural ‘ripples’ can be and a warning for our current world of multiple nomenclatural codes.
Cambridge Core - Natural Resource Management, Agriculture, Horticulture and forestry - Species Conservation - edited by Jamieson A. Copsey
Past human impacts on the riverine ecosystems of North America remain poorly understood. This continent is home to the world's most diverse freshwater mussel fauna, but mussels are particularly vulnerable to human impacts because they are long-lived sedentary filter feeders with complex life histories. A large body of historical and archaeological sources provide an extraordinarily comprehensive record of mussel distribution and in some cases abundance throughout the Holocene that exists for few organisms in general and is unprecedented for invertebrates. Despite high harvest pressure and the potential effects of prehistoric human land use practices on aquatic habitats, no extinctions of mussel species have been documented in North America until the 20th century. However, freshwater mussels have experienced one of the highest rates of extinction of any group of organisms during the past 100 years, primarily due to dam construction and the indirect effects of habitat fragmentation.
The extent to which human activity has influenced species extinctions during the recent prehistoric past remains controversial due to other factors such as climatic fluctuations and a general lack of data. However, the Holocene (the geological interval spanning the last 11,500 years from the end of the last glaciation) has witnessed massive levels of extinctions that have continued into the modern historical era, but in a context of only relatively minor climatic fluctuations. This makes a detailed consideration of these extinctions a useful system for investigating the impacts of human activity over time. This book describes and analyses the range of global extinction events which have occurred during this key time period, as well as their relationship to both earlier and ongoing species losses. By integrating information from fields as diverse as zoology, ecology, palaeontology, archaeology, and geography, and by incorporating data from a broad range of taxonomic groups and ecosystems, this text provides a fascinating insight into human impacts on global extinction rates, both past and present.
Aim By establishing a prehistoric fossil record for the vertebrate fauna of Guam, we can document the composition of the island’s fauna prior to Western contact. It will also complement the extensive prehistoric fossil data already known from the nearby islands of Rota, Tinian and Aguiguan, and improve our understanding of natural distributional patterns through a chronologically deeper view of the biogeography of the Mariana Islands.
Location Northern Guam, Mariana Islands, Micronesia.
Methods Fossil-bearing sediment was removed from karst features with vertically and horizontally controlled excavation methods. Age determinations of the fossils were estimated by radiocarbon dating associated wood charcoal samples.
Results The 3314 bones (fossils) of terrestrial vertebrates date to the past two millennia and represent 34 species. Among 12 species of squamate reptiles, one is extinct (a gekkonid lizard) and another, the monitor lizard, Varanus indicus, was introduced to Guam no later than about 1600 years ago. The 17 species of birds feature five that are extinct. Two others not recorded previously on Guam are extirpated. Eight others were lost on Guam in historic times. We also recovered bones of two species of indigenous bats, (Pteropus sp., extirpated; Emballonura semicaudata, probably extirpated), and non-native rodents, (Rattus spp.).
Main conclusions Guam’s contemporary faunal losses have been well documented since invasion of the Brown Treesnake (Boiga irregularis) during or shortly after WWII. Other exotics, as well as habitat deterioration, have abetted this snake’s deleterious presence. Our data further show that human impact led to declines or losses of vertebrate populations by late prehistoric times. Numerous anthropogenic extirpations would not be evident without studying fossils. Our chrono-stratigraphic evidence argues for the arrival of non-native rats (Rattus sp.) only about 1000 years ago, which helps to explain why a flightless rail survived on Guam into modern times, unlike on most other islands in Oceania.
The Samoan archipelago is situated in the South Pacific Ocean at a latitude of 13°–15° S and a longitude of 168°–173° W, and runs in a west-northwest direction east of Fiji, north of Tonga, south of Tokelau, and west of Niue and the Cook Islands. Its nine inhabited islands and several uninhabited islets, plus two distant coral islands, have a total area of ca. 3,100 km2.
The indigenous vegetation of 'Eua Island, Tonga, is described and a species list presented. Quantitative data were collected from 40 forest plots in which all vascular plant species were recorded and the diameters of all stems ≥ 5 cm dbh were measured. Plot classification, based on basal area data, identified six forest types, two coastal and four inland, which reflect an elevational sequence from the coast to the island's summit (312 m a.s.l.). A polar ordination, based on basal area data, arranged plots from the four inland forest types in a sequence from low to high elevation along one ordination axis, and from more mature to less mature along a second axis. Species richness increased with elevation. Several additional, non-forest vegetation types, including fern- and grass-dominated vegetation of inland ridges and shrub-dominated vegetation of cliffs and rocky shores, were sampled semi-quantitatively and are also described.
Land and freshwater birds and mammals reduce resource use on small oceanic islands. The adjustments used vary among taxa. Rails reduce energy expenditure both by a decrease in body mass and the evolution of flightlessness. Island ducks have responded principally through a reduction in body mass. Bats minimize expenditures by having a small mass, consuming fruit, and often experiencing a direct decrease in the rate of metabolism. Most pigeons reduce energy expenditure through a direct decrease in metabolism and the consumption of fruit. Rodents reduce energy expenditure directly and through a decrease in mass. Reduced resource requirements by individuals permit larger populations, which in turn increases the probability of population survival. On many islands ectotherms have replaced endotherms as herbivores and carnivores; the great reduction of resource use associated with this shift has permitted ectotherms to have both large populations and a large body size. High rates of resource use occur in populations that consist of individuals that are endothermic, large, or highly active, or have unusually high costs of maintenance. These are the species that are least likely to survive on small oceanic islands and habitat ''islands'' produced on continents by human activity.
Faunal remains from archaeological sites on Buka, Nissan, and Tikopia Islands. Southwest Pacific include a number of taxa not previously recorded from those islands. These are Rattus praetor for both Nissan and Tikopia, and Thylogale brunii. Unicomys poneeleti. and Uromys salebrosus for Buka. R. praetor and T. brunii were probably introduced into the region by humans during the mid Holocene. Following the initial expansion in the ranges of these taxa, some island populations became extinct.
In a study supported by the FFPS Oryx 100% Fund, the authors investigated the impact of traditional hunting practices on native land birds in Samoa. Hunting and habitat modification have contributed to the near extinction of several endemic species. Through new hunting regulations, conservation education programmes and the development of a national park system, the Government of Western Samoa has moved to strengthen its commitment to the conservation of a unique insular biota.
How to Cite This Article
Link to This Abstract
Blog This Article
Copy and paste this link Highlight all
http://dx.doi.org/10.1017/S0030605300019803
Citation is provided in standard text and BibTeX formats below.
Highlight all
BibTeX Format
@article{ORX:4960156,author = {Merlin,M. D. and Juvik,J. O.},title = {Bird protection in Western Samoa},journal = {Oryx},volume = {19},issue = {02},month = {4},year = {1985},issn = {1365-3008},pages = {97--103},numpages = {7},doi = {10.1017/S0030605300019803},URL = {http://journals.cambridge.org/article_S0030605300019803},}
Click here for full citation export options.
Blog This Article
Blog This Article
:
Highlight all
Bird protection in Western Samoa
M. D. Merlin and J. O. Juvik (1985).
Oryx , Volume 19 , Issue02 , April 1985, pp 97-103
http://journals.cambridge.org/action/displayAbstract?aid=4960156
The code will display like this
Bird protection in Western Samoa
M. D. Merlin
and J. O. Juvik April 1985
Oryx,
,Volume19,
Issue02,
April 1985,
pp 97-103
http://journals.cambridge.org/abstract_S0030605300019803
M. D. Merlin
and J. O. Juvik
(1985).
Bird protection in Western Samoa.
Oryx,
19,
pp 97-103.
doi:10.1017/S0030605300019803.
Metrics
0Comments
A new genus and species are erected for a giant flightless pigeon described from post‐cranial fossil bones from four Quaternary sites on Viti Levu, Fiji, in the South Pacific Lack of cranial material and transformations associated with large size and loss of flight obscure its relationships, but some characters of the tarsometatarsus, tibiotarsus, and humerus are closer to Goura than to any other taxon The new taxon approaches the dodo and the solitaire in size, but its wings were not as reduced as in these Mascarene birds A tentatively referred premaxilla suggests that the Fiji bird had an unspecialised bill It coexisted with a similar sized, flightless megapode, a terrestrial crocodilian, and a giant iguana, which were the largest animals in prehuman FijiA new volant species of Ducula is described from Lakeba Island in the Lau Group, Fiji that was larger than any extant Ducula, and had more elongate tarsometatarsi than Ducula david, the largest described fossil species Bones of a Ducula similar in size to the Lakeba pigeon are reported from Viti Levu
The late Pleistocene‐Holocene fossil record of megapodes (Aves: Megapodiidae) in the Fiji Islands is examined. Three new taxa are recorded from the group: a new genus and species are erected for a flightless form from Viti Levu that rivals in size the extinct Svlviornis of New Caledonia; a large, flightless species of Megapodius is described from Viti Levu; and Megapodius alimentum Steadman is recorded from Lakeba and Mago islands in the Lau Group. The tarsometatarsus of M. alimentum is redescribed.
The dependency of highly endemic island floras on few potential pollinators in depauperate island faunas suggests that pollinators and seed dispersers may be crucial in the preservation of biodiversity in isolated oceanic islands. We discuss the hypothesis that flying foxes are “strong interactors” in South Pacific islands where they setwe as the principal pollinators and seed dispersers, This suggests that the ongoing decline and ultimate extinction of flying fox species on Pacific islands may lead to a cascade of linked plant extinctions. We propose an empirical test of this hypothesis: comparisons of plant reproductive success in Guam, which has virtually lost its flying fox populations, and Samoa, where signifcant populations remain.Resumen: La dependencia de floras islen̄as altamente endémicas en algunos polinizadores potenciales en faunas islen̄as depauperizadas sugiere que 10s polinizadores y 10s dispersadores de semillas pueden ser cruciales en la conservación de la diversidad biológica en islas oceánicas aisladas. Discutimos la hipotesis de que 10s murcielagos fncgiwros (Pteropus sp.) son fuertes interactores en las islas del Pacíco sur, en donde funcionan como 10s principales agentes de polinizacion y de dispersion de semillas Esto sugiere que la continua disminucion y futura extincion de las especies de murcielagos fncgivoros podri'an llevara una extincion de plani2i.s en cadena Hemos propuesto una pwb a empinca de esta hipotesis, mediante la comparacidn del éxito reproductivo de lasplantas en Guam, quepracticamente ha perdido sus poblaciones de murcielagos fncgiwros, con el de Samoa, donde persisten poblaciones impmtantes.
Based on field studies and a previous review of the literature, 22 plant communities are recognized in the two adjacent South Pacific archipelagoes of Samoa and Tonga. Because of similarities of climate and flora, most of the communities are similar in the two archipelagoes; the major differences result from the coralline nature of most of Tonga and the volcanic nature of Samoa. The communities are briefly described, the dominant species are listed, and the variation between the two archipelagoes is noted.
The botany of four small, relatively undisturbed tuff cone islands off the east coast of Upolu, Western Samoa, is examined. During a series of visits to the islands, the vegetation was studied in nine sample plots, and a checklist of the 260 species comprising the flora was compiled. Six types of native vegetation are recognized, one of which (Diospyros coastal forest) appears to be unique to tuff cone islands. Casual observations were made on the avifauna and turtle species, and the ecological significance of the islands is discussed.
Coordinated geomorphic and archaeological observations indicate that ancient (c. 3000 years old) archaeological sites in Tonga typically lie inland from present coasts on paleoshorelines associated with a regional mid-Holocene highstand of sea level. Shorelines in Tonga include both seacliffs, which dominate windward coasts, and coral sand beaches, many of which fringe accretionary sand flats on leeward coasts. Seacliffs are characteristically notched at high-tide level by solution and bioerosion. Emergent paleoshoreline notches of mid-Holocene and last-interglacial ages record higher local stands of relative sea level on many Tongan islands. Other indicators of local mid-Holocene sea levels include emergent microatolls, paleobeachrock exposures, beach-ridge berm crests, and fossil beach placers of black sand derived from tephra deposits. Paleoshoreline indicators on Tongatapu and 'Eua, and in the Nomuka and Hahake subgroups of Ha'apai, show that mid-Holocene sea level stood 2.0-2.6 m higher than present sea level, with tectonic changes in island elevations negligible since the last interglacial. By contrast, the Vava'u Group and the Kotu subgroup of Ha'apai have subsided at mean Holocene rates of c. 0.5 mm/yr, enough to counteract the post-mid-Holocene fall in local relative sea level. Elevations and locations of ancient archaeological sites are generally compatible with independent geomorphic evidence for stability or subsidence of individual islands. Parts of Tongatapu were evidently inundated in 1853 by the temporary runup of a local tsunami associated with an earthquake generated by volcanic activity along the nearby volcanic arc.
We report two recently received AMS radiocarbon dates from the Polynesian plainware site of Holopeka on Lifuka Island, northern Ha'apai, Tonga. The dates (2800 ± 90 and 2590 ± 60 BP) fall within the long accepted temporal interval for the early eastern Lapita period in Tonga. Possible explanations for these dates are provided with the preferred alternative being the disappearance of decorated ceramics as early as two centuries after first colonization. These dates are commensurate with plainware chronologies elsewhere in western Polynesia.
As background, the physical environment and avifauna of the New Hebrides in the Southwest Pacific are briefly described. The major routes by which birds invaded the New Hebrides are from Australia (possibly via New Caledonia) and from New Guinea via the Bismarcks and Solomons, with a minor route from Fiji. From the New Hebrides, birds in turn colonized New Caledonia, Fiji and Polynesia, the Solomons in a strikingly stratified pattern, the Bismarcks scarcely and New Guinea and Australia not at all. The concept of faunal dominance is supported by the asymmetry of these fluxes of species: the ratio of species exchanged between two archipelagos deviates further from 1.0 than does the ratio of the archipelagos’ areas. Species that colonize archipelagos ‘upstream’ towards the source of colonization often become restricted to small or remote islands, poor in species, thereby generating many of the supertramps of the Pacific. Appendices summarize sources of information about New Hebridean birds and, for each species, its island-by-island distribution within the New Hebrides, extralimital range, closest relatives and references to taxonomic studies.
We surveyed birds on seven small (<3 km2) offshore islands in the Independent State of Samoa to investigate the distribution and abundance of landbirds relative to abiotic and biotic features of these islands. We recorded 17 of the 28 indigenous species of landbirds that reside in Independent Samoa. Species richness among the islands ranged from 3 to 12 species. Other than the domestic chicken, none of the non-native species common on the large islands of ‘Upolu and Savai'i was recorded on offshore islands. Nu'utele, the third-largest of the seven islands, had the greatest proportion of native forest and harbored the most species of landbirds, including five not found on any other offshore island (Tooth-billed Pigeon [Didunculus strigirostris], West Polynesian Ground-Dove [Gallicolumba stairi], Pacific Pigeon [Ducula pacifica], Samoan Whistler [Pachycephala flavifrons], and Samoan Flycatcher [Myiagra albiventris]). The similarly sized Apolima, which is inhabited and extensively cultivated, had only six species, about the same as the much smaller but forested Namua. Manono, the largest island, also has the largest human population, and harbored 10 landbird species. These included two species not recorded on Nu'utele (Banded Rail [Gallirallus philippensis] and Purple Swamphen [Porphyrio porphyrio]), both of which prefer disturbed habitats to native forest. Habitat and human disturbance, rather than abiotic variables such as area and distance to the nearest island, are the primary factors influencing the distribution of birds on small offshore islands, especially those >1.0 km2.
(1) This paper interprets the distributional ecology of breeding land and fresh-water birds of the New Hebrides, in the light of immigration-extinction equilibria. (2) The species-area relation has a lower slope (z=0.05) for the New Hebrides than for archipelagoes nearer the colonization sources of New Guinea and Australia. This difference is attributed to higher intra-archipelagal immigration rates in the New Hebrides, because superior overwater colonizing species are increasingly overrepresented among colonist individuals at increasing distances from the sources. (3) Isolated New Hebridean islands have fewer species than similar-sized central ones. The decrease in species number with distance is steeper on smaller islands. (4) Assignment of species to so-called incidence categories shows that most species are widely distributed geographically as well as ecologically within the archipelago. These categories are correlated with species' habitat preference and level of endemism. Few species have passed beyond the stage of recent colonists in a taxon cycle. (5) A model of incidence functions based on immigration-extinction equilibria for a single species may explain the otherwise puzzling restriction of some species to the larger islands. (6) Many species show untidy distributional gaps along the island chain, while other cases of tidy linear distributions cannot reasonably be attributed to arrested invasions. These patterns suggest that present-day distributions are simply one snapshot of a kaleidoscopic sequence of distributions, generated by immigrations and extinctions. Changes in the intra-archipelagal distributions of a few species on even medium-sized and large islands can be detected on a time scale of decades.
People have lived on tropical Pacific islands over the past 30,000 years (Bismarcks, Solomons) or 3000 to 1000 years (the rest of Oceania). Their activities have led to the loss of many thousands of populations and as many as 2000 species of birds that probably otherwise would exist today. This extinction event is documented by avian fossils from archaeological (cultural) and paleontological (noncultural) sites from nearly 70 islands in 19 island groups. Extinction of birds in Oceania rivals the late Pleistocene loss of large mammals in North America as the best substantiated rapid extinction episode in the vertebrate fossil record. Some avian extinctions in Oceania occurred within a century or less after human arrival, while others required millennia or even tens of millennia. Any of these time frames is rapid in an evolutionary or geochronological sense. Inter-island differences in the speed and extent of extinction can be explained by variation in abiotic (A), biotic (B), and cultural (C) factors. Levels of extinction on large, near islands can be comparable to those on small, remote islands when C factors (such as high human population density and introduction of invasive plants and animals) override A factors (such as large land area or little isolation) or B factors (such as rich indigenous floras and faunas). An innovative, proactive conservation strategy is needed not only to prevent further extinctions of birds in Oceania, but also to restart evolution of some of the lineages that have suffered the most loss, such as flightless rails. This strategy should focus on islands with ABC traits that retard rather than enhance extinction.
Mt Korobaba, near Suva, Fiji, is a steep breccia cone 422 m high, covered by largely unmodified tropical forest. Fifteen percent of the indigenous vascular flora of Fiji was recorded from 15 plots. in a transect located to encompass the marked physiognomic variation in these forests. Agglomerative classifications of floristic and abundance data for the tree, sapling, shrub, herb, and dependent synusiae indicated five strong, but intergrading, types. The major forest types vary structurally from a multi-layered forest, with emergents up to 35 m and a rich development of epiphytes and climbers, to a 4–14 m tall broken-canopied scrub. poor in epiphytes and climbers. The forests along the transect show evidence of continuous regeneration. The “massenerhebung” effect on the Mt Korobaba forests appears to be associated with soil shallowness and exposure to strong winds. as does much of the variation in the vegetation.
The avifauna of Western Samoa is dominated by indigenous species, including several endemic ones. They are primarily birds of the rainforest and, since the islands have already suffered severe loss of this habitat and there is likely to be increased pressure on it in the future, their long-term prospects are not good. At present, introduced, non-native birds are not a threat to indigenous species, being confined largely to urban habitats, and there is little interaction with forest species. Several indigenous species exploit manmodified habitats, however, and it is possible that, as has occurred elsewhere, some of them may adapt fully to urban life.
In February 1990, tropical cyclone Ofa struck Western Samoa with very strong winds (in excess of 200 km/hr). In December 1991, less than 22 months later, tropical cyclone Val struck the same area with similar intensity. In the moist lowland forest of the Tafua Rain Forest Reserve, Savai'i, Western Samoa, we examined the effects of the two cyclones on forest structure, tree mortality, and interspecific differences in damage. Average mortality of trees was high after both cyclones (28% and 33%, respectively). In one forest area, subject to a fire after the first storm, mortality was more than 90 percent. The frequency of uprooted trees was 31 percent after Ofa, but only 16 percent after Val. Uprooting was significantly more frequent among species lacking buttresses or stilt roots. As a combined effect of the two cyclones, the lowland forest of Tafua suffered a 53 percent tree mortality, with remaining standing trees being severely damaged (topped and with a substantial reduction of main branches). Average tree density dropped from an estimated 476 trees/ha (>5 cm DBH), before Ofa to 225 trees/ha after Val. Existent gap sizes are reflected by the changes in mean canopy cover which decreased from nearly 100 percent before Ofa to 27 percent after Val. Post-cyclone recovery is often observed to be very rapid, but the very large gaps created in the Tafua forest and the simultaneous loss of the whole guild of vertebrate seed dispersers (flying foxes and fruit pigeons) suggests it will be a long time before the upper canopy is once again closed.
Owing to extensive prehistoric extinctions of large frugivores, Pacific Pigeons (Ducula pacifica) are thought to be one of the most important seed dispersers of large-seeded plants in Tonga, yet little is known about their interactions with their food plants. We reviewed their known food plants and recorded defaecations, regurgitations, and movement patterns of this species over 11 months in Tonga. The fruit of at least 38 native plant species and the leaf buds of one species are eaten by Pacific Pigeons in Tonga. Most defaecations and all regurgitations contained a single seed of a single species. Pigeons usually regurgitated seeds larger than 20 mm in diameter whereas smaller seeds were typically defaecated. On the basis of observed movement patterns in Tonga and retention times for Ducula, most seeds are probably dispersed away from fruiting trees (85% of regurgitated seeds, 99% of defaecated seeds), but within 50 m of the crown. Distances of more than 100 km are theoretically possible for defaecated seeds, although pigeon behaviour is likely to limit this maximum. Results from this study suggest Pacific Pigeons are excellent seed dispersers in Tonga.
The parrot (Psittaciformes) show many highly distinctive features of head morphology. Jaw and tongue musculature have been investigated in seven other orders, for most of which parrot affinities have been postulated. The functional properties and evolution of various modifications found in parrots are discussed. Several features seen in the Tooth-billed pigeon (Didunculus strigirostris) show a significant trend towards conditions in parrots, favouring the view that the Columbiformes are the order mostly closely related to the Psittaciformes. These features also set Didunculus apart from other pigeons, and it is strongly urged that it be given full family rank.
Archaeological sites in the northern Ha'apai Group of central Tonga occur on small islands within the uplifted forearc belt of the Tonga-Kermadec arc-trench system. The present inland positions of occupation sites that probably once occupied coastal settings imply significant expansion of some island shorelines during late Holocene time (ca. 3250 B.P. to present). Geologic processes leading potentially to enlargement of the islands include continuing forearc uplift, eustatic or glacio-hydro-isostatic fall in sea level following a mid-Holocene highstand, and progressive accretion of beach ridges to island coasts, with or without changes in relative sea level. Radiometric dates for uplifted coral terraces in Tonga indicate that forearc uplift has been negligible during Holocene time. By contrast, theoretical considerations, regional analysis of shoreline indicators throughout the South Pacific, and limited empirical data from Tonga itself all imply that regional sea level has declined locally by 1–2 m since a mid-Holocene highstand (ca. 6000-3000 B.P.), which was a hydro-isostatic response to transfer of water mass from Pleistocene ice caps to the ocean basins. Emergence of originally coastal sites is thus expected since initial settlement of the islands by Lapita peoples. Accretionary coastal flats composed of multiple beach ridges are 250–500 m wide on favorable leeward shores and the flanks of sand cays, but some presently unknown proportion of this incremental island growth may have occurred prior to the post-mid-Holocene decline in relative sea level. Ash falls from tephra eruptions at Tongan volcanoes also modified island environments through Quaternary time. Evidence for significant change in the configuration and morphology of islands in Ha'apai during the period of human settlement highlights the need for systematic interdisciplinary archaeological and geological research in the study of Pacific prehistory. © 1994 John Wiley & Sons, Inc.
Recent excavations in caves and rockshelters on the islands of Tinian, Aguiguan, and Rota (Commonwealth of the Northern Mariana Islands) have yielded a history of vertebrates over the past 2500 years. Bones from these and other sites document these extinct or locally extir-pated species of birds: Tinian: new sp. The bones also portray the loss of nine populations of lizards, one of snake, and two of bats. It appears that chicken, dog, and pig, which occur prehistorically through much of Oceania, were not intro-duced to the Mariana Islands until after European contact. The only non-native, non-human vertebrate with good evidence of living prehistori-cally in the Mariana Islands is the Pacific Rat Rattus exulans, which nev-ertheless is absent in strata older than ca. AD 1000-1200. That flightless rails, especially Gallirallus spp., survived in the Mariana Islands for mil-lennia after human arrival may be related to the lack of chicken, dog, and pig, combined with a 2000–2500 year delay in the introduction of Rattus exulans.
The species richness, taxonomic diversity, and geographic distribution of pigeons and doves (Columbidae) have been altered irreversibly in Polynesia by 3500 years of human activity. Natural (without human influence) columbid faunas are estimated primarily by studying prehistoric bones. In all Polynesian island groups studied (except outlying Easter Island, Hawaiian Islands, or New Zealand), the prehistoric columbid faunas had more species, more genera, and more species per genus than modern faunas from the same island. Congeneric species pairs or triplets occurred on many islands for Ducula, Ptilinopus, and Gallicolumba. The losses of Polynesian columbids include the extinction of at least 9 species in the genera Ducula, Ptilinopus, Macropygia, Caloenas, Gallicolumba, and Didunculus as well as the extirpation of numerous island populations of extant species. If not for human impact, a typical East Polynesian island would support at least 5–6 species of columbids in 3–4 genera (compared to 0–3 species in 0–3 genera today). A typical West Polynesian island would support at least 6–7 species in 4–5 genera (compared to 1–6 species in 1–5 genera today). Since all Polynesian pigeons and doves are frugivorous and/or granivorous, their decline in recent millennia probably has affected the composition of Polynesian forests by limiting inter- and intra-island dispersal of plant propagules.
The Tooth-billed PigeonDidunculus strigirostris (Jardine 1845) shows considerable differences in the morphology of its stout curved bill in comparison to all other pigeon species. The aberrant bill construction is explained as an adaption to the use of specific food plants. The Tooth-billed Pigeon preferably feeds on fruits of theDysoxylum genus (Meliaceae). However, exclusively pea-sized seeds are taken by cutting the viscous fruits by hooking the tip of the upper jaw into the fruit, while the lower jaw with its projections performs a sawing movement. In connexion with this sawing movement of the mandible the unique feature of the quadrate and articulare showing an antero-posterior condyle and cavity instead of the transversal one being present in all other members of the Columbidae this is explicable by considering the feeding habits of this species. Studies in Tooth-billed Pigeon habitats on the Island of Western Samoa revealDidunculus as a tree-living species. The total number of individuals is estimated at 4800 to 7200; the species is threatened by clearcutting of native forest as well as by hunting.
Patterns in species occurrences on islands have been analyzed by several authors. At issue is the number of non-occurring
pairs of species (also known as checkerboards). Previous authors have suggested that if the number of checkerboards differs
from what is expected by chance, then island communities might have been structured by competition. Investigators have pursued
this problem by first generating random (or null) matrices and then testing a metric derived from the collection of null matrices
against the metric calculated from the actual species co-occurrence matrix. The random matrices were constrained by requiring
the number of species on each island, and the number of islands on which each species occurred to be equal to their observed
values. We show that results from previous studies are generally flawed. We present a fast, efficient algorithm to generate
null matrices for any set of fixed row and column sums, and propose a modification of a previously proposed metric as a test
statistic. We evaluated the efficacy of our construction method for null creation and our metric using incidence matrices
from the avifauna of Vanuatu (formerly New Hebrides).
The study of bones from archaeological sites in Eastern Polynesia has revealed much late Holocene extinction of birds. Because this extinction has been found in all Eastern Polynesian archipelagos where bird bones are part of the archaeological record (Marquesas, Society, Pitcairn, and Cook island groups), similar levels of extinction are likely to be found in other Eastern Polynesian island groups (Line, Tuamotu, Gambier, Austral, Easter), if the evidence is sought. Human impact is the most plausible explanation for these extinctions, which begin immediately after peopling of the islands about 2000 years ago and diminish only after the avifaunas are largely depleted.
We evaluate the preservational attributes (element frequency, breakage, burning, cut-marks, rodent gnawing, and age) of ca. 500 bird bones from three prehistoric archaeological sites on the Polynesian islands of Foa and Lifuka in the Ha‘apai Group, Kingdom of Tonga. Two of the sites lie in calcareous beach sands whereas the third is the refuse infilling of a well. Although differing in age, all three sites are unequivocally cultural in origin, as evidenced by rich artifact assemblages and various sedimentological features (pits, hearths, etc.) that reflect human activities. The sites also contain bones from a diverse assemblage of marine fish, marine and terrestrial reptiles (sea turtles, iguanas), and terrestrial mammals (fruit bats, rats, pigs, dogs). We find no evidence for deposition of bones (bird or otherwise) in these Tongan sites by non-human agents. This is expected given that we are unaware of any non-human species or geological process that would concentrate the bones of fishes, reptiles, birds, and mammals on a beach ridge or in a well in Tonga. This is especially the case since the species range from very small to very large, and represent marine, fresh water, coastal, and forested habitats. Nevertheless, clear evidence of cultural involvement cannot be discerned on most individual bones, whether bird or non-bird. Furthermore, most taphonomic attributes (element frequency, breakage, burning, and cut-marks) of bones of a domesticated species (the chicken, Gallus gallus) resemble those found on bones of indigenous landbirds. We believe that all bones in any zooarchaeological assemblage should be evaluated carefully to determine who or what was responsible for their deposition. We see no reason, however, why bird bones should be held to some standard higher than those applied to the bones of other taxa, as some have suggested.
Sprinkled across the tropical Pacific, the innumerable islands of Oceania are home to some of the most unique bird communities on the planet, and they sustain species found nowhere else on earth. Many of the birds that live in this region are endangered, however; many more have become extinct as a result of human activity, in both recent and prehistoric times. Reconstructing the avian world in the same way archeologists re-create ancient human societies, David Steadmanâa leading authority on tropical Pacific avian paleontologyâhas spent the past two decades in the field, digging through layers of soil in search of the bones that serve as clues to the ancient past of island bird communities. His years of indefatigable research and analysis are the foundation for Extinction and Biogeography of Tropical Pacific Birds, a monumental study of the landbirds of tropical Pacific islandsâespecially those from Fiji eastward to Easter Islandâand an intricate history of the patterns and processes of island biology over time. Using information gleaned from prehistoric specimens, Steadman reconstructs the birdlife of tropical Pacific islands as it existed before the arrival of humans and in so doing corrects the assumption that small, remote islands were unable to support rich assemblages of plants and animals. Easter Island, for example, though devoid of wildlife today, was the worldâs richest seabird habitat before Polynesians arrived more than a millennium ago. The forests of less isolated islands in the Pacific likewise teemed with megapodes, rails, pigeons, parrots, kingfishers, and songbirds at first human contact. By synthesizing data from the distant past, Steadman hopes to inform present conservation programs. Grounded in geology, paleontology, and archeology, but biological at its core, Extinction and Biogeography of Tropical Pacific Birds is an exceptional work of unparalleled scholarship that will stimulate creative discussions of terrestrial life on oceanic islands for years to come.
The lizard fauna of Polynesia consists mainly of skinks and geckos that are believed to have reached many of the islands by way of human assistance beginning with the early Polynesian voyagers. Documenting the natural versus human-assisted origins of lizards in the Pacific would be greatly enhanced by a fossil record, but that record for lizards has been limited to a few archaeological and noncultural sites that postdate human arrival. This study reports fossil remains of eight, possibly nine, species of lizards screened from cave sediments on 'Eua, Tonga. One of these deposits is precultural, the deepest layers of which were excavated from below a calcite lens dated at ca. 60,000 to 80,000 yr B.P. Fossils from the precultural strata include a gecko referred to Perochirus sp., a genus known today no nearer than Vanuatu; a skink representing either an undescribed species of Emoia or Emoia trossula Brown & Gibbons; and remains of the widespread Emoia cyanura (Lesson). A single bone of an unidentified large (> 150mm snout-vent length) skink (cf. Emoia, Eugongylus) was recovered from deposits of post-human arrival age, but no such large skinks are currently known from the island. Additional cave sites yielded essentially contemporaneous remains of species extant on 'Eua: Gehyra oceanica (Lesson), Lepidodactylus cf. lugubris (Dumeril & Bibron), Nactus pelagicus (Girard), Cryptoblepharus poecilopleurus (Wiegmann), and Lipinia noctua (Lesson). No fossil evidence was found of the Crested Iguana, Brachylophus fasciatus (Brongniart), whose presence on 'Eua never has been verified by specimens.
Based on fieldwork in 1995 and 1996, I assess the distribution, relative abundance, and habitat requirements of indigenous species of land birds on 13 islands in the Ha'apai Group, Kingdom of Tonga. Among the islands visited, primary forest still exists only on the large (46.6 km2), high (558 m) volcanic island of Tofua. Vegetation on the 12 smaller (0.15-13.3 km ), lower (6-45 m) islands is dominated by a mosaic of active and abandoned agricultural plots, nearly all with an overstory of coconut trees. Because of cultivation practices, very little of this vegetation is reverting to secondary forest. Of the 15 resident species of land birds that survive on these islands, nine are widespread and at least locally common within Ha'apai, although only four (Gallirallus philippensis, Ptilinopus porphyraceus, Halcyon chloris, Aplonis tabuensis) certainly or probably occur nowadays on all 13 islands. Three species (Gallicolumba stairii, Ptilinopus perousii, Clytorhynchus vitiensis) are extirpated or extremely rare on all islands surveyed except Tofua. Overall species richness and abundance of land birds are much greater on Tofua than on the other islands. This difference may be due more to the presence of primary forest on Tofua than to Tofua's greater area and elevation.
Molecular systematic studies generally assume that gene trees are reasonable estimates of species trees. We tested the validity of this assumption in the pigeons and doves (Aves: Columbiformes) by comparing phylogenies derived from nuclear (beta-fibrinogen intron 7) and mitochondrial (cytochrome b) genes. Trees derived from the two genes when analyzed separately contained many nodes in common. A partition homogeneity test revealed no significant incongruence between trees derived from the two genes; so, we combined nuclear and mitochondrial data in subsequent phylogenetic analyses. The resulting tree, which was highly resolved and generally well supported, contained a strong biogeographic component. The rate of nucleotide substitution for the nuclear intron was approximately six times slower than that of cytochrome b. This resulted in a much higher consistency index for trees derived from the intron because of the low level of multiple substitution. However, the degree of resolution and support for trees reconstructed from the two genes was similar. We also examined the transition and transversion substitution rates for the genes. Third position transversions for cytochrome b accumulated linearly with intron divergence, suggesting low levels of multiple substitution for third position transversions.