Speciation and phylogeography of Hawaiian terrestrial arthropods

The Hawaiian archipelago is arguably the world's finest natural laboratory for the study of evolution and patterns of speciation. Arthropods comprise over 75% of the endemic biota of the Hawaiian Islands and a large proportion belongs to species radiations. We classify patterns of speciation within Hawaiian arthropod lineages into three categories: (i) single representatives of a lineage throughout the islands; (ii) species radiations with either (a) single endemic species on different volcanoes or islands, or (b) multiple species on each volcano or island; and (iii) single widespread species within a radiation of species that exhibits local endemism. A common pattern of phylogeography is that of repeated colonization of new island groups, such that lineages progress down the island chain, with the most ancestral groups (populations or species) on the oldest islands. While great dispersal ability and its subsequent loss are features of many of these taxa, there are a number of mechanisms that underlie diversification. These mechanisms may be genetic, including repeated founder events, hybridization, and sexual selection, or ecological, including shifts in habitat and/or host affiliation. The majority of studies reviewed suggest that natural selection is a primary force of change during the initial diversification of taxa.     

Biodiversity and biogeography of Henderson Island's insects

Henderson Island is an example of a raised coral atoll, and as such supports a much more diverse biota than geographically similar low atolls. It is also, due to its remote location, largely undisturbed by the activities of humans. It is therefore unique in the Pacific Ocean, and comparable to Aldabra in the Indian Ocean. Biogeographically it is also interesting as it is amongst the most easterly islands of the Indo-West Pacific region, and has been largely colonized by species dispersing from island to island across the ocean from the west. New and extensive collections of insects were made in 1991. Although not fully identified yet, it is clear that the fauna is depauperate, with only about 180 species known to date. Despite its easterly location almost all species are derived from the west, and much of the fauna is likely to be indigenous. The most diverse orders are the Lepidoptera ( c. 53 spp.), Coleoptera ( c. 38 spp.), Diptera ( c. 37 spp.), Hymenoptera ( c. 21 spp.), Homoptera ( c. 14 spp.) and Heteroptera (4 spp.). Of particular interest are the weevils, Heteroptera and Homoptera which exhibit considerable endemism with perhaps some examples of intra-island radiation. Although depauperate, Henderson supports a much larger insect fauna than that of nearby Ducie Atoll (total known insect fauna =15 spp).     

Behaviour, natural history, and annual cycle of the Henderson Island rail Porzana atra (Aves: Rallidae)

The little known endemic Henderson Island rail (or Henderson rail) Porzflna atra , inhabits forest on the coastal plain and upraised plateau of Henderson Island. Rails were studied for 15 months from January 1991 to March 1992. The population was estimated at c. 6200 individuals living in pairs or cooperative groups of 3–4 adults on territories averaging about 1 ha. Two or three eggs were laid in covered or open nests near the ground from mid-July to mid-February. Up to five consecutive nesting attempts were made in cases where eggs or young chicks were lost. Adults laid a second clutch when chicks were fully feathered at about one month of age. Both sexes incubated and helped rear the young. Older chicks sometimes helped feed younger siblings. Dispersal of juveniles from the natal territory took place in April. Adult birds underwent a rapid, simultaneous post-nuptial moult of the remiges in February-April; the post-juvenile moult involved body feathers only. Data on morphometries, breeding ecology, courtship behaviour and voice are compared with available information for the spotless crake P. tabuensis , the Henderson rail's closest relative and probable ancestor. These comparisons provide some information on how these two taxa have differentiated since rails arrived on Henderson Island some time in the last 380000 years.     

Island biogeography of the Mediterranean sea: the species–area relationship for terrestrial isopods

Aim We looked at the biogeographical patterns of Oniscidean fauna from the small islands of the Mediterranean Sea in order to investigate the species–area relationship and to test for area‐range effects. Location The Mediterranean Sea. Methods We compiled from the literature a data set of 176 species of Oniscidea (terrestrial isopods) distributed over 124 Mediterranean islands. Jaccard's index was used as input for a UPGMA cluster analysis. The species–area relationship was investigated by applying linear, semi‐logarithmic, logarithmic and sigmoid models. We also investigated a possible ‘small island effect’ (SIE) by performing breakpoint regression. We used a cumulative and a sliding‐window approach to evaluate scale‐dependent area‐range effects on the log S/log A regression parameters. Results Based on similarity indexes, results indicated that small islands of the Mediterranean Sea can be divided into two major groups: eastern and western. In general, islands from eastern archipelagos were linked together at similarity values higher than those observed for western Mediterranean islands. This is consistent with a more even distribution of species in the eastern Mediterranean islands. Separate archipelagos in the western Mediterranean could be discriminated, with the exception of islets, which tended to group together at the lowest similarity values regardless of the archipelago to which they belong. Islets were characterized by a few common species with large ranges. The species–area logarithmic model did not always provide the best fit. Most continental archipelagos showed very similar intercepts, higher than the intercept for the Canary island oceanic archipelago. Sigmoid regression returned convex curves. Evidence for a SIE was found, whereas area‐range effects that are dependent on larger scale analyses were not unambiguously supported. Main conclusions The Oniscidea fauna from small islands of the Mediterranean Sea is highly structured, with major and minor geographical patterns being identifiable. Some but not all of the biogeographical complexity can be explained by interpreting the different shapes of species–area curves. Despite its flexibility, the sigmoid model tested did not always provide the best fit. Moreover, when the model did provide a good fit the curves looked convex, not sigmoid. We found evidence for a SIE, and minor support for scale‐dependent area‐range effects.     

Initial checklist of fishes from Henderson Island, Pitcairn Group

Notes are given on the presence and distribution of reef fishes at Henderson Island (24^o21'S, 128^o19'W) from two separate visits in 1971 and 1991. Limited collections were made in 1971, whilst 1991 records are based on confirmed sightings and in situ photographs. 183 species from 49 families are listed, with museum numbers and lengths being given for collected specimens. This is thought to represent 80–90% of species present. The family with the greatest representation is the Labridae with 21 species. Only 31% of species appear to be shared with neighbouring Ducie Atoll, 390 km to the east, from where 138 species have been recorded, though this low percentage may simply reflect the greater recording effort undertaken at Henderson. Levels of endemism in the Pitcairn Group as a whole appear low (<2%).     

Biodiversity growth on the volcanic ocean islands and the roles of in situ cladogenesis and immigration: case with the reptiles

Models for biodiversity growth on the remote oceanic islands assume that in situ cladogenesis is a major contributor. To test this, we compiled occurrence data for 194 terrestrial reptile species on 53 volcanically‐constructed middle‐ to low‐latitude landmasses worldwide. Despite 273 native island‐species records, there are only 8–12 cases of the phenomenon, including just two radiations. Diversification frequencies are largely uncorrelated with island area, age, maximum altitude, and isolation. Furthermore, there is no indication that the presence of non‐sister congeners on an island stymies the process. Diversity on individual oceanic islands therefore results primarily from immigration and anageneis, but this is not a simple matter. Clusters that are difficult to reach (far or challenging to get to) or thrive upon (e.g. Canaries, Galápagos) have relatively few clades (3–8), some of which have many species (6–14), and all host at least one endemic genus. In these settings, diversity grows mainly by intra‐archipelago transfer followed by within‐island anagenetic speciation. In contrast, those island groups that are easier to disperse to (characterized by short distances and conducive transit conditions) and harbour more benign habitats (e.g. Comoros, Lesser Antilles) have been settled by many ancestor‐colonizers (≥ 14), but each clade has few derived species (≤ 4). These archipelagoes lack especially distinctive lineages. Models explaining the assembly and growth of terrestrial biotic suites on the volcanic ocean islands thus need to accommodate these new insights.     

Island ecology and contingent theory: the role of spatial scale and taxonomic bias

Scale, the scale dependency of patterns and processes, and the ways that organisms scale their responses to these patterns and processes are central to island and landscape ecology. Here, we take a database of studies in island ecology and investigate how studies have changed over a 40-year period with respect to spatial scale and organisms studied. We demonstrate that there have been changes in the spatial scale of islands studied and that there is taxonomic bias in favour of vertebrates in island ecological studies when compared to scientific publications as a whole. We discuss how such taxonomic bias may have arisen and discuss the implications for ecology and biogeography.     

Vouchering DNA‐barcoded specimens: test of a nondestructive extraction protocol for terrestrial arthropods

Morphology‐based keys support accurate identification of many taxa. However, identification can be difficult for taxa that are either not well studied, very small, members of cryptic species complexes, or represented by immature stages. For such cases, DNA barcodes may provide diagnostic characters. Ecologists and evolutionary biologists deposit museum vouchers to document the species studied in their research. If DNA barcodes are to be used for identification, then both the DNA and the specimen from which it was extracted should be vouchered. We describe a protocol for the nondestructive extraction of DNA from terrestrial arthropods, using as examples members of the orders Acarina, Araneae, Coleoptera, Diptera, and Hymenoptera chosen to represent the ranges in size, overall sclerotization, and delicacy of key morphological characters in the group. We successfully extracted sequenceable DNA from all species after 1–4 h of immersion in extraction buffer. The extracted carcasses, processed and imaged using protocols standard for the taxon, were distinguishable from closely related species, and adequate as morphological vouchers. We provide links from the carcasses and DNA vouchers to image (MorphBank) and sequence (GenBank) databases.     

Island biology: looking towards the future

Oceanic islands are renowned for the profound scientific insights that their fascinating biotas have provided to biologists during the past two centuries. Research presented at Island Biology 2014—an international conference, held in Honolulu, Hawaii (7–11 July 2014), which attracted 253 presenters and 430 participants from at least 35 countries¹—demonstrated that islands are reclaiming a leading role in ecology and evolution, especially for synthetic studies at the intersections of macroecology, evolution, community ecology and applied ecology. New dynamics in island biology are stimulated by four major developments. We are experiencing the emergence of a truly global and comprehensive island research community incorporating previously neglected islands and taxa. Macroecology and big-data analyses yield a wealth of global-scale synthetic studies and detailed multi-island comparisons, while other modern research approaches such as genomics, phylogenetic and functional ecology, and palaeoecology, are also dispersing to islands. And, increasingly tight collaborations between basic research and conservation management make islands places where new conservation solutions for the twenty-first century are being tested. Islands are home to a disproportionate share of the world''s rare (and extinct) species, and there is an urgent need to develop increasingly collaborative and innovative research to address their conservation requirements.     

岛屿生物地理学理论：模型与应用

前言岛屿有许多显著特征,如地理隔离,生物类群简单。这些特点为重复性研究和统计学分析奠定了基础,从而有利于许多深入而细致的生物学研究。因此,岛屿为发展和检验自然选择、物种形成及演化,以及生物地理学和生态学诸领域的理论和假设,提供了重要的自然实验室。岛屿生物地理学理论(MacArthurwilson学说)即为岛屿生物学研究中所产生的著名理论之一。该理论发展之     

Placing empirical limits on metapopulation models for terrestrial plants

Both island-biogeographic (dynamic) and niche-based (static) metapopulation models make predictions about the distribution and abundance of species assemblages. We tested the utility of these models concerning such predictions for terrestrial vascular plants using data from 74 landscapes across the globe. We examined correlations between species frequency and local abundance and shapes of the species frequency distribution. No data set met all of the predictions of any single island-biogeographic metapopulation model. In contrast, all data sets met the predictions of the niche-based model. We conclude that in predicting the distribution of species assemblages of plants over scales greater than 10–1 km, niche-based models are robust while current metapopulation models are insufficient. We discuss limitations in the assumptions of the various models and the types of empirical observations that they will each have to deal with in further developments.     

Biodiversity and biogeographic affiliation of Bryozoa from King George Island (Antarctica)

King George Island (KGI), which is located between the Antarctic and South American continents, may play a crucial role in the exchange of Bryozoa amongst the various Antarctic sectors and across the Polar Front. Knowledge regarding the biological diversity of this area could help us understand the evolution of the Antarctic ecosystem and its connectivity to the South American continent as well as the colonization ability of particular species. Here, we investigate the patterns of diversity and biogeographic affiliation of the cheilostome Bryozoa from KGI and the surrounding areas. Of 114 identified taxa from a depth range of 6–492 m, 26 species were reported for the first time in KGI. The most speciose genera were Camptoplites, Osthimosia, Smittina, and Cellarinella. Species richness at KGI consisted of 70% of the total bryozoans at the South Shetland Islands (SSI). Fifty-nine per cent of the bryozoans from KGI are endemic to Antarctica, which closely reflects the previously estimated endemism rate for bryozoans and other Antarctic taxa. Cluster analysis indicated that the strongest faunal links of SSI bryozoans were with Antarctic Peninsula assemblages, corresponding to the physical distance between both locations. The biogeographic similarities between SSI and South America confirm the broad trend of existing Antarctic–South American faunal links previously observed in bryozoans and many other taxa and indicate that SSI might be an important transitional zone between Antarctica and South America.     

The bark and ambrosia beetles (Curculionidae, Scolytinae) of Cocos Island, Costa Rica and the role of mating systems in island zoogeography

Cocos Island is a small oceanic island midway between Costa Rica and the Galápagos Archipelago; about 2 Myr in age, it is the only tropical oceanic island in the eastern Pacific with tropical wet forest. We identified several hundred bark beetle specimens collected during recent expeditions by INBio, the National Biodiversity Institute of Costa Rica, and re-examined all specimens from earlier collections. We report 19 species in ten genera, seven or eight of which are endemic, making scolytines the largest group of beetles known from the island. We describe as new Pycnarthrum pseudoinsulare , Xyleborinus cocoensis , and Xyleborus sparsegranulosus , resurrect Xyleborus bispinatus as separate from X. ferrugineus , and report six other species as new to Cocos Island. Three-quarters of the scolytines reproduce by brother–sister mating, and we argue that inbreeders are superior island colonists because they are less affected than are outbreeders by problems of mate location and inbreeding depression. The fauna and flora of Cocos Island arrived by dispersal and human transport. We examine natural colonization patterns for the fauna, using the distributions of the relatives of island endemics: most colonization came from the Americas, but the closest relatives to some endemics are found on Caribbean or Galápagos islands. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 89 , 729–743.     

Stream invertebrate communities of Campbell Island

Invertebrates at 20 sites on 19 Campbell Island streams were sampled over the Austral summer of 1996/97. Twelve of the 16 benthic invertebrate taxa known from the island were collected. The most abundant group was the Crustacea, which included an isopod (Notidotea lacustris) and two amphipods, one belonging to the family Eusiridae and one to the suborder Gammaridea. Five species of Diptera were found (three chironomids; Orthocladiinae sp., Chironominae sp. and Maoridiamesa insularis, as well as an empidid and a simuliid Austrosimulium campbellense). One trichopteran, the hydroptilid caddis Oxyethira albiceps and two plecopteran species Rungaperla campbelli and R. longicauda and unidentified Oligochaetes were also collected. In general, Campbell Island streams are stable, deeply incised, have unusually high salinity from wind-blown sea spray and a unique benthic invertebrate fauna. With the exception of high altitude streams with large boulders which had invertebrate communities dominated by Crustacea and the endemic stonefly of the genus Rungaperla, none of the measured environmental variables or geographic location could explain the distinctive communities found. The species-poor stream fauna and the absence of many invertebrate families commonly found on mainland New Zealand appears to be related to the extreme isolation and geological history of the island.     

Classification of the terrestrial habitats on Marion Island based on vegetation and soil chemistry

Abstract. Soil chemistry and vegetation data for 176 sites on sub‐Antarctic Marion Island (47° S, 38° E) were subjected to Canonical Correspondence Analysis. 21 habitats in six habitat complexes were recognized from a clustering analysis of the site scores on the canonical axes. Another two habitats and one habitat complex were added to this. The resultant habitat classification closely reflects the between‐habitat variation in the relative magnitudes of the main forcing variables that determine ecological succession on the island (moisture, exposure, parent soil material, salt‐spray and manuring and trampling by seals and seabirds). It can be used by persons with a minimum of botanical or soil expertise. The habitat complexes (number of habitats in complex) are: Coastal Salt‐spray Complex (2); Fellfield (2); Slope (6); Biotic Grassland (3); Biotic Herbfield (3); Mire (6); Polar Desert (1). A key is provided whereby the habitat to which a particular site belongs can be determined using botanical criteria, although infrequently soil moisture and pH information is also needed. Summaries of the soil chemistry and vegetation characteristics of the various habitats are also provided.