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.     

Hormonema schizolunatum, a new species of dothideaceous black yeasts from phyllosphere

Two black yeast isolates from plants from the Canary Islands (Spain) are described and illustrated. Absence of Woronin bodies at simple septal pores, local coralloid terminal hyphal cells, indeterminate thallus maturation, the presence of budding cells and local conversion to meristematic growth all indicate a relationship to the Dothideaceae (Dothideales, Ascomycota). Morphological properties were consistent with the genus Hormonema Lagerberg & Melin, as defined by presence of percurrent conidiogenous loci alongside undifferentiated hyphae, and results of PCR-ribotyping supported this classification. The isolates were judged to belong to a hitherto undescribed species, characterized in particular by curved conidia soon developing transverse septa. The physiological profile of this species is also described.     

Geographic variation in scalation of the lizard Gallotia stehlini within the island of Gran Canaria

The lacertid lizard ( Gallotia stehlini ), an endemic of Gran Canaria, shows no visually obvious geographic variation, yet all seven scalation characters that were examined exhibit significant geographic variation. The number of collar scales, scales along the ventral trunk and femoral pores are correlated with habitat type, while the number of femoral pores is correlated negatively with altitude. Mantel tests were used to compare simultaneously an observed pattern with three hypothesized patterns (habitat type, altitude and proximity). They indicate that, while several individual characters are significantly associated with the putative causal factors of habitat type and altitude, there is no association between an overall scalation distance matrix and habitat type, or altitude when the effect of proximity is removed. Consequently, one should consider the individual characters as well as the multivariate generalized distances. Some of the observed patterns of geographic variation in scalation are very similar to those of the small scincid lizard Chalcides sexlineatus on Gran Canaria and also parallel the altitudinal and latitudinal variation in the scalation of the Tenerife lacertid ( Galotia galloti ). The low level of congruence in patterns of geographic variation in individual characters (i.e. some vary with latitude, some with altitude and one varies with longitude) is consistent with the hypothesis that ecogenetically caused geographic variation may result in lower inter-character congruence than phylogenetically caused geographic variation.     

Progressive island colonization and ancient origin of Hawaiian Metrosideros (Myrtaceae)

Knowledge of the evolutionary history of plants that are ecologically dominant in modern ecosystems is critical to understanding the historical development of those ecosystems. Metrosideros is a plant genus found in many ecological and altitudinal zones throughout the Pacific. In the Hawaiian Islands, Metrosideros polymorpha is an ecologically dominant species and is also highly polymorphic in both growth form and ecology. Using 10 non-coding chloroplast regions, we investigated haplotype diversity in the five currently recognized Hawaiian Metrosideros species and an established out-group, Metrosideros collina, from French Polynesia. Multiple haplotype groups were found, but these did not match morphological delimitations. Alternative morphologies sharing the same haplotype, as well as similar morphologies occurring within several distinct island clades, could be the result of developmental plasticity, parallel evolution or chloroplast capture. The geographical structure of the data is consistent with a pattern of age progressive island colonizations and suggests de novo intra-island diversification. If single colonization events resulted in a similar array of morphologies on each island, this would represent parallel radiations within a single, highly polymorphic species. However, we were unable to resolve whether the pattern is instead explained by ancient introgression and incomplete lineage sorting resulting in repeated chloroplast capture. Using several calibration methods, we estimate the colonization of the Hawaiian Islands to be potentially as old as 3.9 (-6.3) Myr with an ancestral position for Kaua'i in the colonization and evolution of Metrosideros in the Hawaiian Islands. This would represent a more ancient arrival of Metrosideros to this region than previous studies have suggested.     

Significance of new records of Tridacna squamosa Lamarck, 1819, in the Tuamotu and Gambier Archipelagos (French Polynesia)

The giant clam subfamily Tridacninae (family Cardiidae) is an important group of bivalve molluscs found throughout the Red Sea and Indo-Pacific, from East Africa to the Eastern Pacific biogeographic region. The Tridacna genus is currently revised with numerous cryptic species identified with molecular markers. New Tridacna records from the fringe of the known distribution areas are extremely useful to identify genetically unique species, geographic ranges, and to examine processes associated with species differentiation. While Tridacna maxima is abundant in French Polynesia (Central South Pacific Ocean) the larger fluted giant clam Tridacna squamosa was formerly reported only in the Austral Islands in the south. Following a recent survey that spanned 23 islands and atolls of the Society, Tuamotu and Gambier Archipelagos, the presence of T. squamosa between the Cook Islands and Pitcairn Islands is confirmed using both morphological and molecular information, suggesting a relic distribution across the Central Pacific Ocean. Tridacna squamosa is rare, but present throughout Tuamotu and Gambier. However, it remained undetected from the Society Islands, probably due to historical over-fishing. This species is valued by local inhabitants, and is sought after mainly as gifts and also for a limited local shell trade. The rarity of T. squamosa may call for conservation measures in the near future.     

Implications of goat eradication on the survivorship of the Galapagos hawk

Non-native mammals cause ecological disasters in island ecosystems and their eradication is usually considered beneficial to native biodiversity. Goats (Capra hircus) were introduced to Santiago Island, Galapagos, Ecuador, in the early 1800s, and their numbers increased to about 100,000 by 1970. A goat eradication campaign initiated in 2002 was successful, eliminating the last individuals in 2006. To evaluate the effects of goat eradication, between 1998 and 2010 we studied the Galapagos hawk (Buteo galapagoensis) population on Santiago Island before, during, and after eradication. We used a 12-year data set in a capture–mark–recapture analysis to estimate the apparent survivorship of territorial adults in 33 breeding territories, and a 5-year data set to estimate the population sizes of the floater (non-territorial) fraction of the population. Juvenile floaters showed a drastic decline starting in 2006 and continuing in 2007, 2008, and 2010, which we attribute to the completion of goat eradication in 2006, and subsequent habitat changes. We found a significant decline in adult survivorship after the goat eradication program. Additionally, group size positively affected adult survivorship in this cooperatively polyandrous raptor, presumably reflecting the benefit of shared defense and offspring provisioning during harsher conditions. The changes in the hawk population after goat eradication are an example of unforeseen consequences of a restoration program, and we hypothesize that these changes are adjustments towards a new equilibrium under the current ecosystem characteristics and capacity. © 2012 The Wildlife Society.     

Islands within islands: a molecular phylogenetic study of the Leucocroton alliance (Euphorbiaceae) across the Caribbean Islands and within the serpentinite archipelago of Cuba

Aim Our aim was to investigate the historical biogeography of the three genera of the Leucocroton alliance (i.e. Garciadelia Jestrow & Jiménez Rodr., Lasiocroton Griseb., and Leucocroton Griseb., Euphorbiaceae). Location  The alliance is restricted to the Bahamas, Cuba, Hispaniola and Jamaica. Methods Members of the Leucocroton alliance, along with representatives from tribe Adelieae (Adelia L. and Philyra Klotzsch.), were included in a molecular phylogenetic analysis based upon nucleotide sequences of the internal transcribed spacer region of the nuclear ribosomal DNA and the non‐coding chloroplast regions psbM–trnD and ycf6–pcbM. The program s‐diva was used to calculate ancestral areas based on the phylogenetic trees and present species distributions. Results Phylogenetic analyses support the monophyly of the three genera. The ancestral area of the Leucocroton alliance is eastern Cuba and Hispaniola. Ancestral forms of Leucocroton arose on eastern Cuba and underwent two migrations across the island. The ancestor of Lasiocroton also originated on eastern Cuba followed by later dispersal to and speciation events on the other islands. Our study also suggests that ancestral forms of the Leucocroton alliance probably occurred on limestone soils. Main conclusions Our study concurs with previous hypotheses suggesting that the flora of serpentinite regions of the Caribbean derives from other types of soils. The serpentine endemics of the Leucocroton alliance have a single origin and represent one of the most extraordinary examples of speciation in this unique environment of the New World. The high colonization success achieved by the members of Leucocroton on serpentine soils was not attained by the other genera of the alliance, which occur on limestone areas.