A new genus, three new species and two new records of extinct Holocene birds from Réunion Island, Indian Ocean

Benthic foraminiferal extinctions linked to late Pliocene–Pleistocene deep-sea circulation changes in the northern Indian Ocean (ODP Sites 722 and 758)

AimThe islands of the south‐western Indian Ocean region are home to many endemic bird species, with their closest relatives occurring in Africa and Madagascar, Eurasia, the Sunda Islands, and the Australasian region. Among owls, the extant endemic scops owls (genus Otus) from Madagascar, Comoros, Seychelles, and Socotra are related to the Southeast Asian species, O. sunia, the Oriental scops owl. Three owl species, presumably Otus derivatives, twice the size of standard scops owls and now extinct, once inhabited the Mascarene Islands, and have been placed in a separate genus, Mascarenotus. Insular apomorphies have made their precise relationships difficult to determine. Here we investigate the phylogenetic position of these enigmatic owls.LocationThe Mascarene Islands (Réunion, Mauritius, Rodrigues) in the south‐western Indian Ocean.MethodsPhylogenetic relationships were reconstructed using ancient DNA extracted from subfossil remains. Fragments of cytochrome b gene were amplified and sequenced. The ancient sequences were analysed with modern sequences of 19 ingroup Otus taxa using Bayesian and Maximum Likelihood methods.ResultsThe Mauritian extinct species M. sauzieri was reconstructed as the sister to both O. pauliani (Grand Comoro) and O. rutilus (Madagascar). The Rodrigues extinct species M. murivorus was the sister, in a star‐like differentiation, to the preceding clade as well as the remaining Comorian species and a clade formed by O. insularis (Seychelles) and O. sunia.Main conclusionsThe ancestor of O. sunia simultaneously colonized Rodrigues Island (evolving into Otus murivorus), Madagascar, and part of the Comoros Islands around 3 million years ago. Later, presumably from Madagascar, new lineages colonized Grand Comoro and Mauritius (O. sauzieri). Independently, a more recent O. sunia ancestor colonized the Seychelles Islands and Socotra. These colonizations were probably favoured by Pliocene cyclonic events, stronger and more frequent than today. Several features, including giantism, wing reduction, and a relative decrease in skull and orbit size evolved convergently in the polyphyletic species O. sauzieri and O. murivorus.

Amphisamytha (Annelida: Ampharetidae) from Indian Ocean hydrothermal vents: Biogeographic implications

Irregular distributions of planktonic foraminifera and stratigraphic correlation

AimThe aim was to document the impact of the globalization of human activity on the biodiversity and biogeographical patterns of reptilian and amphibian faunas across islands worldwide.LocationIslands worldwide.Time periodFrom the 15th century to the present time.Major taxa studiedReptiles and amphibians.MethodsWe compiled lists of the reptilian and amphibian species that occurred on islands before the 15th century and of those that occur currently. For each species group, we calculated differences in species richness and in compositional similarities among islands, between the two periods. Regression models were used: (a) to associate the observed differences with spatial patterns of geographical, climatic, biotic and human factors; and (b) to quantify changes in the relative importance of non‐human factors in explaining the spatial patterns of species richness and compositional similarity.ResultsThe richness of reptile and amphibian species increased consistently across islands worldwide. Hotspots of increase were detected in the Caribbean and the Indian Ocean. The composition of species assemblages was substantially homogenized; this was particularly true for amphibians within the Caribbean Sea and for reptiles within the Caribbean Sea and Indian Ocean and between the Indian and the Pacific Oceans. Our results showed that spatial patterns of change in species richness and compositional similarity are driven by human and natural factors. The driving role of mean annual temperature is particularly consistent, and current reptile richness and compositional similarity patterns for both species groups are increasingly being shaped by the global temperature gradient.Main conclusionsThe globalization of human activity is eroding the regionalized character of insular herpetofaunas and leading to the emergence of global‐scale gradients of taxonomic composition and species richness. Projections of increasing rates of biological invasions, extinctions and climate change suggest that these changes are likely to be aggravated even further in the coming decades.

Almost 90% of global bird extinctions have occurred on islands. The loss of endemic species from island systems can dramatically alter evolutionary trajectories of insular species biodiversity, resulting in a loss of evolutionary diversity important for species adaptation to changing environments. The Western Indian Ocean islands have been the scene of evolution for a large number of endemic parrots. Since their discovery in the 16th century, many of these parrots have become extinct or have declined in numbers. Alongside the extinction of species, a number of the Indian Ocean islands have experienced colonization by highly invasive parrots, such as the Ring‐necked Parakeet Psittacula krameri. Such extinctions and invasions can, on an evolutionary timescale, drive changes in species composition, genetic diversity and turnover in phylogenetic diversity, all of which can have important impacts on species potential for adaptation to changing environmental and climatic conditions. Using mtDNA cytochrome b data, we resolve the taxonomic placement of three extinct Indian Ocean parrots: the Rodrigues Psittacula exsul, Seychelles Psittacula wardi and Reunion Parakeets Psittacula eques. This case study quantifies how the extinction of these species has resulted in lost historical endemic phylogenetic diversity and reduced levels of species richness, and illustrates how it is being replaced by non‐endemic invasive forms such as the Ring‐necked Parakeet. Finally, we use our phylogenetic framework to identify and recommend a number of phylogenetically appropriate ecological replacements for the extinct parrots. Such replacements may be introduced once invasive forms have been cleared, to rejuvenate ecosystem function and restore lost phylogenetic diversity.

Well versed in natural history, particularly geology and ornithology, Hugh Edwin Strickland (1811–53) became fascinated by the dodo and mankind's influence on its extinction. Seeking to investigate this flightless bird and other extinct species from islands in the Indian Ocean, he invited the comparative anatomist Alexander Gordon Melville (1819–1901) to help him separate myth from reality. Divided into two sections, this 1848 monograph begins with Strickland's evaluation of the evidence, including historical reports as well as paintings and sketches, many of which are reproduced. Melville then analyses the osteology of the dodo and Rodrigues solitaire, describing his findings from dissections of the few available specimens and making comparisons with similar species. A seminal work, it correctly concluded that the dodo was more closely related to pigeons than vultures, and the book also inspired others to take up the search for new fossil evidence.

Devil rays (Mobula spp.) are caught in fisheries across the Indian Ocean, with reports of significant recent declines in catch and sightings. Globally, the few populations studied have extremely low population growth rates due to low fecundity and long reproductive cycles, making them highly vulnerable to overfishing. To allow for assessment of the current sustainability of devil ray catch in the Indian Ocean, we provide estimates of age using the caudal vertebrae; somatic growth using a Bayesian, multi-model approach; maximum intrinsic rate of population increase (rmax); and fishing mortality for Endangered Spinetail Devil Ray (Mobula mobular) and Bentfin Devil Ray (M. thurstoni) sampled from small-scale fisheries catch in Indonesia, Kenya, and Pakistan. The oldest individuals of Spinetail Devil Ray (n = 79) and Bentfin Devil Ray (n = 59) were 17.5 and six years, respectively. Both species had relatively low growth coefficients (k = 0.05 and g = 0.19 year−1, respectively), with the von Bertalanffy and logistic models providing the best fitting growth models, and low rmax (0.109 and 0.107 year−1, respectively) indicating that they are highly sensitive to overexploitation. Fishing mortality F estimates (0.16 and 0.18 year−1, respectively) were higher than rmax and exploitation ratio E (0.77 and 0.80, respectively) were higher than an optimum value of 0.5 for biological sustainability for both species, suggesting that the fisheries catches of the species are unsustainable. We demonstrate an approach to assess data-poor species and apply this to two Indian Ocean devil ray species. The results highlight the urgent need for better management actions to reduce the catch of all devil rays to prevent species extinction and aid in population recovery.

The Greater Himalayas hold the largest mass of ice outside polar regions and are the source of the 10 largest rivers in Asia. Rapid reduction in the volume of Himalayan glaciers due to climate change is occurring. The cascading effects of rising temperatures and loss of ice and snow in the region are affecting, for example, water availability (amounts, seasonality), biodiversity (endemic species, predator-prey relations), ecosystem boundary shifts (tree-line movements, high-elevation ecosystem changes), and global feedbacks (monsoonal shifts, loss of soil carbon). Climate change will also have environmental and social impacts that will likely increase uncertainty in water supplies and agricultural production for human populations across Asia. A common understanding of climate change needs to be developed through regional and local-scale research so that mitigation and adaptation strategies can be identified and implemented. The challenges brought about by climate change in the Greater Himalayas can only be addressed through increased regional collaboration in scientific research and policy making.

Climate change and coral reef bleaching: An ecological assessment of long-term impacts, recovery trends and future outlook

Flying-foxes (Pteropodidae) show a high rate of island endemism, but island-endemic taxa have shown a high rate of decline and extinction, mostly because their small population sizes are susceptible to hunting pressure and habitat loss. The Christmas Island flying-fox is restricted to the 135 Km2 Christmas Island (Indian Ocean), as either an endemic species Pteropus natalis or a markedly distinct subspecies of Pteropus melanotus. Given recent declines and extinctions of other native vertebrate species on this Island, this study sought to monitor population trends for this taxon. Monitoring flying-foxes at roost sites is difficult because they are highly vagile, not all roost sites may be known to observers, and dense vegetation at some sites may make counts inaccurate. These constraints are particularly evident on Christmas Island. In this study, we sought to establish a monitoring program complementary to roost counts, and to assess changes in reporting rate from a baseline sampling of 107 sites spaced across the Island in 2006 to a repeat sampling of those sites in 2012. Every site was visited four times, at night, over a period of 4–6 weeks in June–July of 2006 and of 2012, and observers reported whether or not they heard or saw flying-foxes around the sample site. A reporting incidence measure (varying from 0 to 4) was derived for every site. This measure showed a significant decline (of 39%) between the 2006 and 2012 sampling. The observed rate of decline suggests that this taxon is of considerable conservation concern, and merits further conservation action: indeed in 2014 its Australian conservation status was changed from not listed to Critically Endangered. The cause of the current decline is not yet known, but this study indicates that factors additional to hunting and habitat loss may affect island flying-fox species.

<em><span style="text-decoration: underline;">Lysmata debelius</span></em><strong>, </strong>commonly known as the Fire Shrimp or Scarlet Cleaner Shrimp is a highly demanded, pricy marine crustacean exported from Sri Lanka. However, information on captive breeding technology has not been reported so far in the country. Currently, majority of <em><span style="text-decoration: underline;">L. debelius</span></em> exported from Sri Lanka, is captured from the Indian Ocean, thus creating a threat of extinction of this indigenous species if not sustainably managed. Even in the global scale, the major obstacle in commercial production of <em><span style="text-decoration: underline;">L. debelius</span></em> is the poor survival of larvae accompanied by the lengthy larval life. Hence, this study was conducted with the objective of developing a captive breeding protocol and a larviculture technology as viable solutions to those problems. Purified natural sea water was used and natural environment was simulated. An effective broodstock diet was identified. Spawning chamber where water was conditioned with the diatom <em><span style="text-decoration: underline;">Chaetoceros gracillis</span></em> was used for spawning. Larviculture was performed in glass aquariums of 108 L. Feeding regime was developed for day 1-4, day 5-12, and day 13 to juvenile stage. Under the newly developed protocol, the duration of metamorphosis of larvae to juveniles was 50-90 days post hatching with the survival rate of 12.7 ± 0.1% to 18.35 ± 0.15%, reporting the lowest larval duration and the highest survival rate reported so far for captive breeding of <em><span style="text-decoration: underline;">L. debelius</span></em> anywhere in the world. Survival of juvenile shrimps was 100%. Experience of larviculture trials over the years was instrumental in developing this successful methodology. These results lay a firm foundation for future research and development of marine ornamental shrimp culture technology in Sri Lanka.

The Eocene-Oligocene is a time of transition from a warm early Tertiary world with low vertical and latitudinal thermal gradients to the Neogene world with steep vertical oceanic gradients and high latitudinal gradients between equator and poles. The transition between these two regimes occurred primarily between the middle Eocene and middle Oligocene and can be observed in faunal and floral assemblage changes, associated paleotemperature changes, periodic current intensification as implied by increased carbonate dissolution and hiatuses, eustatic sea level changes, and the curious association of microtektites and iridium anomalies with several of these intervals. Population studies of planktonic foraminifers in 14 DSDP sites in the Atlantic, Pacific, and Indian Oceans indicate a general cooling trend between the middle Eocene and Oligocene. Major faunal changes indicating cooling episodes occur, however, at discrete intervals: middle Eocene 44 to 43 Ma (P13); middle/late Eocene boundary 41 to 40 Ma (P14/P15); late Eocene 39 to 38 Ma (P15/P16); Eocene/Oligocene boundary 37 to 36 Ma (P18); and late Oligocene 31 to 29 Ma (P20/P21). Each cooling episode resulted in the extinction of warmer water species and evolution and dominance of cooler water species. This trend is associated with the development of a steep vertical thermal gradient and resulting stratification in the upper water masses (0 to 300 m, 1,000 ft) in the latest Eocene. 18The presence of microtektites and iridium anomaly in latest Eocene sediments has resulted in the scenario of catastrophic extinctions due to a bolide impact. The present study reveals multiple microtektite occurrences at 43 Ma, 40 Ma, 38 Ma, 34 Ma, and 30 Ma. Moreover, these microtektite occurrences coincide with intervals of increased carbonate dissolution and/or hiatuses. This suggests that microtektites are concentrated as a result of carbonate dissolution and selective winnowing of sediments at these intervals. Consequently, a concentration of microtektites in deep-sea sediments may not always imply a bolide impact, nor is there any evidence of catastrophic extinctions during Eocene-Oligocene time. End_of_Article - Last_Page 494------------

The Eastern Arc Mountains of Tanzania and Kenya, a montane archipelago of 13 uplifted fault blocks (sky islands) isolated by lowland arid savanna, are a center of exceptional biological endemism. Under the influence of humid winds from the Indian Ocean, forests and associated species may have persisted in this region since the final uplift of these blocks in the late Miocene. Today, these mountains are inhabited by a remarkable diversity of bird species. To better understand the evolutionary processes behind this diversity, we combined molecular phylogenetic studies of East African montane birds with paleoclimate modeling of its montane forests. Across its largest lowland barrier, the 125 km between the Usambara and Nguru/Nguu Mountains, 10 of the 14 bird lineages exhibited a phylogeographic break. Using Bayesian methods, we established that at least three periods of forest contraction and expansion affected the diversification of Eastern Arc birds. Habitat distribution models suggest that lower-elevation hills may have acted as stepping-stones connecting isolated highlands to allow for the dispersal of montane forest-dependent species across them. Periods of vicariance during paleoclimatic cycles extending back through the Last Glacial Maximum would have then isolated these populations within the highlands they had reached. The broad distribution of neoendemic species across the mountains of East Africa provides evidence of climate cycling as a driver of lineage diversification. The high incidence of narrow-range endemism of paleoendemic species on the Usambara, Uluguru, and Udzungwa Mountains of this region is harder to explain. Our paleoclimate models retrodicted the persistence of montane forest during climate cycles on several Eastern Arc sky islands but not on the Southern Tanzania Volcanic Highlands. Consistent with recent theoretical work, different rates of local extinction rather than increased rates of lineage diversification may explain the pattern of excessive narrow-range endemism on some sky islands over others. Thus, a regional filtering effect is generated, with paleoendemics maintaining populations through time only in areas where habitat persisted, providing a credible explanation for the dramatic variance in levels of endemism among different East African sky islands.

Plant–animal mutualisms such as seed dispersal can play an important role in enabling some species to become invasive. For example, an introduced species could become invasive because birds prefer its fruits to those of native plants. To investigate this possibility, we compared various measures of fruit quality of 22 of the most common native and invasive woody species on the oceanic island Mahé (Seychelles, Indian Ocean).Individual measures of food quality tended to vary much more amongst invasive species than amongst native species; thus, whereas for particular traits the fruits of some invasive species had higher values than any native species, others had relatively low values. However, invasive species consistently produced fruits with a lower water content, resulting in a higher relative yield (i.e. dry pulp weight to total wet fruit weight ratio), and a higher energy content. The fruits of the most abundant invasive tree Cinnamomum verum (Lauraceae) were of particularly high nutritional quality, with individual berries containing 3.5 times more protein and 55 times more lipid than the median values of the native species.We suggest that our results may reflect a general tendency for island plants to produce fruits of low energy content, perhaps reflecting reduced competition for dispersal agents on isolated islands. In addition, we argue that inconsistent results on the relevance of fruit quality for plant invasions reported in the literature may be resolved by comparing the widths of trait spectra for native and alien floras rather than average values. Gaps in the native fruit trait spectrum may provide opportunities for particular invasive species, and weaken the resistance of regional floras to invasions. Such empty niche opportunities may occur for several reasons, including generally broader trait spectra in globally assembled alien than regional native floras (especially on oceanic islands), or the loss of native species due to human activities. More generally, a focus on trait variation rather than average trends may help to advance generalisation in invasion biology.