A new species of rail (Aves: Rallidae) from the Upper Pleistocene and Holocene of Eivissa (Pityusic Islands, western Mediterranean)

A new species of rail is described from a Pleistocene and Holocene cave deposit on the island of Eivissa, Pityusic Islands (western Mediterranean Sea). Rallus eivissensis sp. nov. was an insular relative of the European Water Rail Rallus aquaticus . Compared with the extant Water Rail, the new species was smaller and stouter, had shorter and more robust hind limbs and shorter wings, with probably reduced flight ability. The Pityusics were the only Mediterranean islands with a vertebrate Quaternary fauna lacking terrestrial mammals, and this absence is no doubt related to the Eivissan rail evolution. The chronology of the Rallus eivissensis sp. nov. extinction overlaps broadly with a period of uncertainty for the arrival of humans at Eivissa, suggesting a relationship between the two events.     

Microevolutionary patterns and processes of the Native Hawaiian colonizing fern Odontosoria chinensis (Lindsaeaceae)

Abstract.— The vascular‐plant flora of the Hawaiian Islands is characterized by one of the highest rates of species endemism in the world. Among flowering plants, approximately 89% of species are endemic, and among pteridophytes, about 76% are endemic. At the single‐island level, however, rates of species endemism vary dramatically between these two groups with 80% of angiosperms and only 6% of pteridophytes being single‐island endemics. Thus, in many groups of Hawaiian angiosperms, it is possible to link studies of phylogeny, evolution, and biogeographic history at the interspecific and interisland levels. In contrast, the low level of single‐island species endemism among Hawaiian pteridophytes makes similar interspecific and interisland studies nearly impossible. Higher levels of interisland gene flow may account for the different levels of single‐island endemism in Hawaiian pteridophytes relative to angiosperms. The primary question we addressed in the present study was: Can we infer microevolutionary patterns and processes among populations within widespread species of Hawaiian pteridophytes wherein gene flow is probably common? To address this broad question, we conducted a population genetic study of the native Hawaiian colonizing species Odontosoria chinensis. Data from allozyme analyses allowed us to infer: (1) significant genetic differentiation among populations from different islands; (2) historical patterns of dispersal between particular pairs of islands; (3) archipelago‐level patterns of dispersal and colonization; (4) founder effects among populations on the youngest island of Hawaii; and, (5) that this species primarily reproduces via outcrossing, but may possess a mixed‐mating system.     

Low reproductive success of the endangered Takahe Porphyrio mantelli on offshore island refuges in New Zealand

Many of New Zealand's endangered birds have been transferred from the “mainland” of the North and South Islands to smaller coastal islands free from introduced predators and competitors. The transfer of Takahe Porphyrio mantelli (Plate 1) to offshore islands is unique because these highly endangered, flightless rails are being moved from alpine-tussock habitat of Fiordland, the last remaining natural population, to substantially different lowland habitat on island refuges. Despite the fact that 30% of the approximately 160 Takahe left in the wild now live on coastal islands, a detailed analysis on the success of the island populations has never been undertaken. Using data available from New Zealand's Department of Conservation, we found that while adult survivorship of Takahe on islands is high, reproductive success is significantly lower than in Fiordland. Most factors examined, including inbreeding and nutrient deficiency, had no significant effect on reproductive success of Takahe breeding on islands. Island pairs produced fewer eggs and juveniles in the first year of their pair bond relative to all other years. Hence the large number of transfers of birds between islands during the initial stages of the relocation program may have resulted in a higher frequency of pair formation and thus may have contributed to the islands' lower reproductive success. Why first clutches did so poorly (four juveniles from 43 clutches) compared with second (11 from 36) and third (six from 13) clutches is not known but was one of the main contributing factors for island pairs making greater nesting effort but significantly lower returns than birds breeding in Fiordland. In addition, some individual birds have been very successful in producing young relative to other birds, suggesting that important differences in quality of some breeders may also exist. We expect island productivity will improve over time as the number of interisland transfers of Takahe decreases and as the proportion of breeding birds raised in the island environment increases.     

The orthopteroids of the Seychelles: a threatened island fauna

Although they are conspicuous components of the native fauna, the orthopteroid insects of the Seychelles islands have attracted little attention from ecologists and conservationists throughout most of the twentieth century. Yet, at a complex crossroads, where the Afro-tropical, Malagasy and Oriental faunal regions overlap, they are potentially valuable biogeographical indicators in a region with an extremely complex palaeogeography. The taxonomic isolation of a number of species, incipient speciation among others, as well as possible interisland divergence in some cases make them worthy subjects of evolutionary studies. Most of the endemic species are indicators of undisturbed habitats and some play a role in food chains as the prey of endemic birds and hunting wasps (Sphecidae). The Seychelles orthopteroids are vulnerable to habitat disturbance caused by human activity and are now mainly confined to patches of native vegetation. They are threatened by further encroachment and by introduced predators and competitors.     

Herbivore-deterring secondary compounds in heterophyllous woody species of the Mascarene Islands

Heterophylly (juvenile-adult leaf dimorphism) is widespread among native woody species of the Mascarene Islands, but the causes to this phenomenon have so far not been fully explained. The absence of mammals and dominance of now extinct giant tortoises and flightless birds are characteristics of the original Mascarene fauna. The present study investigates the hypothesis that the distinct morphology and colouration of juvenile leaves signalled unpalatability to browsing giant tortoises or birds. Juvenile and adult leaves of 28 heterophyllous woody species endemic to the islands of Mauritius and Rodrigues were screened for possible chemical defences against herbivory. The screening comprised the following classes of secondary compounds: alkaloids, cyanogenic constituents, saponins, simple phenolics, tannins and anthocyanins. The screening showed that there are no consistent significant differences between juvenile and adult leaves regarding any of the studied secondary compound classes, with the exception of the level of anthocyanins, which was significantly higher in juvenile leaves. This difference was also clearly reflected in a generally high degree of red patterning of juvenile leaves. Based on comparisons with floras of other oceanic islands once inhabited by tortoises and birds, and an evaluation of feeding habits of these herbivores, we suggest that the reduced lamina and partly red colouration of juvenile leaves may be an evolutionary response to selective herbivory by birds.     

Radiocarbon evidence for a prehistoric deliberate translocation: the weasel (Mustela nivalis) of Mallorca

We present radiocarbon evidence for the presence of the weasel (Mustela nivalis) on Mallorca prior to the Roman colonization of the Balearics. Bone collagen from a single specimen recovered at Cova del Ninot, Mallorca rendered two radiocarbon ages, independently obtained at two laboratories (2σ interval: 386–206 cal BC). These dates indicate that the translocation of the weasel to Mallorca occurred in Late Prehistory. The inhabitants of Mallorca at that time were the Talaiotic people (Iron Age settlers of the Balearics). The weasel appears to have been introduced by Talaiotic mercenaries returning to the island on Carthaginian ships. This is the first documented case of the translocation of a wild carnivorous mammal to the Gymnesic Islands (i.e., Mallorca and Menorca) in prehistoric times. Some ecological consequences of this invasion are outlined.     

Terrestrial vertebrates of the New Hebrides: origin and distribution.

The known terrestrial vertebrate fauna of the New Hebrides consists of 16 species of mammals (excluding feral domestic stock), 61 species of resident land- and freshwater birds, 20 species of reptiles and one amphibian. Of these, three, five, four and one species respectively have apparently been introduced by man. The non-introduced fauna is clearly Indo-Australian in origin, but some species have an exclusively Pacific island distribution and others (two bats, seven birds, and four lizards) are endemic. On the six islands visited 95 out of the possible 98 vertebrate species occur. Santo, the largest and most northerly island, supports the richest fauna. The comparative impoverishment of more southerly islands is not directly attributable to the progressive increase in isolation and distance from presumptive source area, nor to decrease in island area or maximum height.     

Inter-island movements and population differentiation in a pelagic seabird

We used mark-resight data and amplified fragment length polymorphism (AFLP) markers to assess movements and gene flow between Central Pacific breeding colonies of the great frigatebird, Fregata minor. Of 715 adult frigatebirds marked on Tern Island and Johnston Atoll, 21.3% were resighted at other frigatebird colonies at least 582 km away. Mark-resight data indicated regular movement of males and females between Tern Island and Johnston Atoll (873 km apart), and less frequent movements to other islands; no birds marked on Tern or Johnston were seen on Christmas Island, but one was seen in the Philippines, 7627 km from where it was marked. Despite the regular occurrence of interisland movements, Bayesian analyses of AFLP data showed significant genetic differentiation between Tern Island and Johnston Atoll, and more pronounced differentiation between these two islands and the more distant Christmas Island. The AFLP profiles of three birds breeding on Tern Island fell within the profile-cluster typical for Christmas Island birds, both in a nonmetric multidimensional scaling analysis and in a population assignment test, suggesting dispersal events from Christmas Island to Tern Island. Several factors could explain the persistence of genetic structure despite frequent movements between colonies: many movements occurred during the nonbreeding season, many breeding-season movements did not involve mate-acquisition behaviours and individuals that do disperse may be selected against, as suggested by morphometric differences between colonies. The persistence of genetic structure among breeding colonies despite significant interisland movements suggests limits to the effectiveness of migration as a homogenizing force in this broadly distributed, extremely mobile species.     

Diversification of the forest beetle genus Tarphius on the Canary Islands, and the evolutionary origins of island endemics

The flightless beetle genus Tarphius Erichson (Coleoptera: Colydiidae) is a distinctive element of the beetle fauna of the Canary Islands with 29 species distributed across the five western islands. The majority of Tarphius species are rare and intimately associated with the monteverde forest and only two species occur on more than one island. In this study we investigate the phylogeography of the Canary Island Tarphius, and their relationship to Tarphius from the more northerly archipelagos of Madeira and the Azores using maximum parsimony and Bayesian inference analysis of mitochondrial cytochrome oxidase I and II sequence data. We use geological datings for the Canary Islands, Azores, and Madeira to calibrate specific nodes of the tree for the estimation of divergence times using a penalized likelihood method. Data suggest that the Canary Island species assemblage is of some antiquity, however, much of this species diversity is relatively recent in origin. The phylogenetic relationships of species inhabiting the younger islands of El Hierro and La Palma indicate that colonization events between islands have probably been a significant factor in the evolutionary history of the Canary Island species assemblage. A comparison of molecular phylogenetic studies of arthropods on the Canary Islands suggests that, in the evolution of the arthropod species community of an island, the origin of endemic species is initially the result of colonizing lineages differentiating from their source populations. However, as an island matures a greater proportion of endemic species originate from intra-island speciation.     

First record of potential bird pollination in the holoparasitic genus Orobanche L.

Pollinators play an important role in the reproduction of zoophilous plants. A shift in pollinators has often been observed for oceanic island plants, probably because of the differences in fauna. In this study, we obtained data on pollinator shifts from insects to birds in Orobanche boninsimae (Orobanchaceae), a holoparasitic plant species endemic to the Bonin (Ogasawara) Islands, oceanic islands in the Pacific. We observed pollination and measured seed viability in O. boninsimae and its continental sister species O. coerulescens. We found that two passerine birds, the Japanese white-eye (Zosterops japonicus) and bulbul (Hypsipetes amaurotis squameiceps), visited the flowers and sucked the nectar of O. boninsimae, while only insects visited those of O. coerulescens. Viable seeds were produced under pollinator-excluded treatments in the two Orobanche species, indicating that the seeds were produced by automatic self-pollination and/or apomixis. These results suggest that O. boninsimae may be pollinated by birds and can produce seeds by automatic self-pollination/apomixis. This is the first record of visitation of the genus Orobanche by birds. Studies of pollination systems in native plants on the Bonin Islands are few compared to those on other oceanic islands, and O. boninsimae may provide a valuable example of pollinator shifts in the Bonin Islands.     

THE AVIAN ECOLOGY OF A TUSSOCK ISLAND IN THE FALKLAND ISLANDS

In the windswept and treeless Falkland Islands, the natural vegetation has been seriously depleted by two centuries of extractive farming. One habitat—mature Tussock-grass—is of vital importance to the resident birds, and those Tussock-covered islands that remain in a nearly natural state can support a far greater density and variety of bird species than any areas on the mainland.
Kidney Island maintains a diverse avian fauna because it offers abundant cover, nest-sites, nest materials and food. In and around the dense mature Tussock-grass which covers about 90% of the surface, 28 bird species nest on the island; 18 of them occupy one or other of the six minor habitats which can be distinguished in the Tussock-grass. The nest-sites and interrelationships of these breeding species are described.     

Genetic variation of pantropical Terminalia catappa plants with sea‐drifted seeds in the Bonin Islands: suggestions for transplantation guidelines

The Bonin Islands are endowed with endemic species. However, these species are at risk of extinction because of the exuberance of invasive alien plants. Therefore, native plant species should be revegetated after eradicating alien plants. We investigated the genetic variation of Terminalia catappa populations in the Bonin Islands by using nuclear (n) microsatellites (simple sequence repeats [SSRs]) and chloroplast (cp) DNA. No significant differences were observed in the genetic diversity of nSSRs among 22 populations. However, recent bottlenecks were detected in three populations on the Chichijima Island group. nSSR variation and cpDNA haplotypes suggested the presence of two genetically distinct groups in the Mukojima and Chichijima Island groups and the Hahajima Island group. A similar genetic structure was observed in plants and animals in the Bonin Islands. Populations on the three islands, which were separated from other islands in each island group when the water depth was 50‐m lower than the present level, were dominated by unique nSSRs clusters, suggesting that historical changes in island connections during the Pleistocene era affected genetic substructuring. These results suggested that different factors contributed to the genetic structure of T. catappa on different geographic scales. At the whole‐island level, the genetic structure was determined by long‐distance seed dispersal by ocean currents. At the island‐group level, the genetic structure was determined by historical changes in island connections caused by changes in the sea level due to glacial–interglacial transition. These findings would help in establishing transplantation zone borders for revegetating T. catappa on the Bonin Islands.     

Biodiversity in the Gulf of Guinea: an overview

Patterns of species-richness and endemism in the Gulf of Guinea reflect the region's biogeographic history. Bioko is a continental-shelf island that was recently connected to the African mainland, whereas Príncipe, São Tomé and Annobón are truly oceanic and have never been connected with each other or with the mainland. As a result, Bioko supports a much more diverse flora and fauna but with relatively low levels of endemism at the species level, whereas the oceanic islands are relatively depauperate because of their isolation but rich in endemic taxa. Species endemism is 0–3% on Bioko for angiosperms, bats, birds, reptiles and amphibians, compared with much higher values on Principe for these same taxa of 8% (plants) to 100% (amphibians), on São Tomé between 14% (plants) and 100% (amphibians), and on Annobón 0% (bats) to 71% (reptiles). On a global scale, for their size both Príncipe and São Tomé support unusually high numbers of single-island endemic species of birds, reptiles and amphibia. For its tiny size, Annobón is also notable for its endemic birds and reptiles. Among terrestrial molluscs the rates of endemism are in general higher than for plants and vertebrates, from ca 50% on Bioko to ca 80% on the oceanic islands. In contrast and as might be expected, only Bioko supports a rich freshwater fish fauna and it contains many endemic taxa, whereas the oceanic islands support only a few salt-tolerant species. The Gulf of Guinea islands are also important for their marine organisms, amongst which coral reef fish and marginellid molluscs show high levels of endemism, though they are not especially species-rich. The Gulf of Guinea islands are of great interest to conservationists and evolutionary biologists. Each island, of greatly differing size and degree of isolation, has acquired its unique sub-set of plants and animals separately from the neighbouring mainland, followed by adaptive radiations in situ. For this reason the conservation value of the archipelago as a whole is greater than the sum of the biodiversity contained in its individual islands. Conservation initiatives in the Gulf of Guinea should therefore ensure that representative terrestrial, freshwater and marine habitats and groups of organisms are targeted in a co-ordinated manner among the islands.     

Molecular phylogenetics of the Macaronesian-endemic genus Bystropogon (Lamiaceae): palaeo-islands, ecological shifts and interisland colonizations

Abstract A molecular phylogenetic study of Bystropogon L'Her. (Lamiaceae) is presented. We performed a cladistic analysis of nucleotide sequences of the internal transcribed spacers (ITS), of the nuclear ribosomal DNA, and of the trnL gene and trnL-trnF intergenic spacer of the chloroplast DNA. Bystropogon odoratissimus is the only species endemic to the Canary Islands that occurs in the three palaeo-islands of Tenerife. This species is not part of an early diverging lineage of Bystropogon and we suggest that it has a recent origin. This phylogenetic pattern is followed by most of the species endemic to the palaeo-islands of Tenerife. The two sections currently recognized in Bystropogon form two monophyletic groups. Taxa belonging to the section Bystropogon clade show interisland colonization limited to the Canary Islands with ecological shifts among three ecological zones. Taxa from the section Canariense clade show interisland colonization both within the Canary Islands and between the Canary Islands and Madeira. Speciation events within this clade are mostly limited to the laurel forest. The genus has followed a colonization route from the Canaries towards Madeira. This route has also been followed by at least five other plant genera with species endemic to Macaronesia. Major incongruences were found between the current infrasectional classification and the molecular phylogeny, because the varieties of Bystropogon origanifolius and Bystropogon canariensis do not form two monophyletic groups. The widespread B. origanifolius appears as progenitor of the other species in section Bystropogon with a more restricted distribution.     

Extinction of the autochthonous small mammals of Mallorca (Gymnesic Islands, Western Mediterranean) and its ecological consequences

Aim To investigate the chronology, causes and consequences of the extinction of the autochthonous Pleistocene small mammals of Mallorca. Location Mallorca (Gymnesic Islands, Balearics, Western Mediterranean). Methods We have obtained the first direct ¹⁴C ages from the bone collagen of selected samples of two extinct endemic small mammals from Mallorca: the Balearic dormouse, Eliomys morpheus (Rodentia: Myoxidae) and the Balearic shrew, Asoriculus hidalgoi (Soricomorpha: Soricidae). We also present evidence for the absence of both endemics from the earliest Mallorcan archaeological sites and for the introduction of the garden dormouse, Eliomys quercinus, and the wood mouse, Apodemus sylvaticus. Combined information from direct dating of bone collagen of E. quercinus and A. sylvaticus and from cultural associations provides an adequate framework to establish the chronology of the faunal change and to compare it with the chronological information available on climatic change and the first arrival of humans on the islands. Results The chronological record includes the latest evidence available for the survival of endemic species and the earliest introduction of small mammals into Mallorca. We present ‘uncertainty periods for extinction’ (UPEs) of both endemic mammals based on the chronology of their last occurrence and on the inferred timing of their extinction (restricted UPEs). Main conclusions Possible causes for the extinction of autochthonous small mammals on Mallorca are discussed. Once we have discarded climatic causes, predation by invasive species, competition with newcomers and habitat deterioration, the introduction of diseases emerges as the most reasonable explanation for these extinctions. Based on the identification of changes in keystone species in Mallorcan ecosystems, we propose a tentative schedule of key ecological changes that have taken place over the past 5 millennia.     

Relationships between floral morphology and pollinator fauna in insular and main island populations of Hosta longipes (Liliaceae)

We compared the floral morphologies and pollinator fauna and morphologies of Hosta longipes var. longipes on the main Japanese island of Honshu and var. latifolia on the Izu Islands to examine the differentiation processes of H. longipes in the island system. The corolla length was shorter on the southern Izu Islands than on the main island and northern Izu Islands. However, the size of other flower parts of H. longipes did not simply decrease across main island Honshu and the Izu Islands, unlike other Izu endemic plant species studied previously. Instead, the floral morphology showed a complicated variation pattern. Pollinator fauna of H. longipes on the Izu Islands varied more widely than those on the main island. The diverse pollinator fauna may have influenced the morphological differentiation of H. longipes on these islands.     

Genetic variation tracks ecological segregation in Pacific island black flies

Geographic isolation is widely viewed as a key component of insular radiations on islands. However, strong ecological affinities may also reinforce isolation and promote genetic divergence. The black fly fauna in the Society Islands French Polynesia is notable for the number of closely related endemic species (31), and the morphological and habitat diversity of the larvae. Here, we measure ecological and morphological differences within and between two closely related species, Simulium oviceps and Simulium dussertorum and relate these differences to genetic distance. Phylogenetic analyses of a 920 bp fragment of the cytochrome oxidase I (COI) gene revealed a well-supported, ecologically divergent S. oviceps clade (larvae found in rivers instead of cascades) that shows little morphological differentiation. For both S. oviceps and S. dussertorum, genetic distance among populations is related to larval habitat, with cascade populations showing greater isolation from each other than river populations. Our data support the hypothesis that larval ecological shifts have played a role in the radiation of this black fly fauna.     

Population genetics of threatened wild plants in Japan

Approximately one-fourth of Japan's native plant species are threatened with extinction. To conserve these species, it is critical to evaluate genetic diversity at species-level and population-level. Some factors, including population size and geographic distribution, are known to influence the population genetic diversity of wild plant species. This article briefly reviews the population genetic studies that have been conducted on wild threatened plants in Japan. A large population size or wide geographic distribution does not always lead to large genetic diversity, suggesting that historical factors such as speciation processes and population expansion often play more important roles in determining genetic diversity than the number of remnant individuals. The mating system of a species also affects genetic diversity; predominantly selfing species tend to have smaller genetic diversity than outcrossing congeners. Another issue of concern in the conservation genetics of wild plants in Japan is the genetic diversity of insular endemics, because Japan consists of many islands, and the insular flora contains many endemic and threatened species. Previous studies on endemic plants on the Bonin and the Ryukyu Islands are reviewed. Compared to the cases of the Bonin Islands or other oceanic islands, there is much larger genetic diversity in plants endemic to the Ryukyu Islands. This difference is probably the result of the differences in the geological history of these islands. Electronic Publication     

High levels of genetic diversity in island populations of the island endemic Suzukia luchuensis (Labiatae)

Genetic diversity and genetic differentiation within and among island populations was examined by allozyme electrophoresis in Suzukia luchuensis (Labiatae), which is endemic to four of the Ryukyu Islands, southern Japan, and one island near Taiwan. Intrapopulation allozyme diversity was very low in all the four Ryukyu Islands, probably due to the effects of random drift in small populations. In contrast, genetic diversity at the species level was high, possibly because of an ancient origin of populations and/or multiple colonization of the species on different islands. Genetic differentiation among the overall populations was high (G(ST)=0.863), while gene flow (Nm) as estimated from allozyme frequency data was 0.041, suggesting that its occurrence among populations is highly restricted. Hierarchical analysis of genetic differentiation indicated that a high proportion of the total allelic variance is attributed to variation among islands, corresponding to the fact that several alleles were fixed on only one island. However, intraisland genetic differentiation was small on all islands except Yonaguni Island, where S. luchuensis is relatively widely distributed. Most diversity was thus due to differences among islands.     

Molecular biogeography and diversification of the endemic terrestrial fauna of the Hawaiian Islands

Oceanic islands have played a central role in biogeography and evolutionary biology. Here, we review molecular studies of the endemic terrestrial fauna of the Hawaiian archipelago. For some groups, monophyly and presumed single origin of the Hawaiian radiations have been confirmed (achatinelline tree snails, drepanidine honeycreepers, drosophilid flies, Havaika spiders, Hylaeus bees, Laupala crickets). Other radiations are derived from multiple colonizations (Tetragnatha and Theridion spiders, succineid snails, possibly Dicranomyia crane flies, Porzana rails). The geographic origins of many invertebrate groups remain obscure, largely because of inadequate sampling of possible source regions. Those of vertebrates are better known, probably because few lineages have radiated, diversity is far lower and morphological taxonomy permits identification of probable source regions. Most birds, and the bat, have New World origins. Within the archipelago, most radiations follow, to some degree, a progression rule pattern, speciating as they colonize newer from older islands sequentially, although speciation often also occurs within islands. Most invertebrates are single-island endemics. However, among multi-island species studied, complex patterns of diversification are exhibited, reflecting heightened dispersal potential (succineids, Dicranomyia). Instances of Hawaiian taxa colonizing other regions are being discovered (Scaptomyza flies, succineids). Taxonomy has also been elucidated by molecular studies (Achatinella snails, drosophilids). While molecular studies on Hawaiian fauna have burgeoned since the mid-1990s, much remains unknown. Yet the Hawaiian fauna is in peril: more than 70 per cent of the birds and possibly 90 per cent of the snails are extinct. Conservation is imperative if this unique fauna is to continue shedding light on profound evolutionary and biogeographic questions.