Distinct geographical structure across species units evidenced by chloroplast DNA haplotypes and nuclear ribosomal ITS genotypes of Corylopsis (Hamamelidaceae) in the Japanese islands

The geographical distribution of chloroplast DNA (cpDNA) haplotypes and nuclear ribosomal internal transcribed spacer (nrITS) genotypes of Japanese Corylopsis (Hamamelidaceae), which consists of four species, was investigated. Two hundred and five individuals belonging to four species from 30 populations, covering the entire geographical range, were studied. Based on approximately 1108 bp of the three non-coding regions of cpDNA, nine haplotypes were detected, and each was distinguished from adjacent haplotypes by one substitution. Based on approximately 507-bp nrITS sequences, 47 genotypes were detected, for which three clades were identified in the phylogenetic analysis. There was inconsistency between the cpDNA haplotypes, nrITS genotypes, and classification of Corylopsis taxa, possibly because of incomplete lineage sorting or introgressive hybridization. The distribution of the haplotypes was highly structured geographically, and N _ST (0.893) was significantly greater than G _ST (0.819), implying that the current distribution of Corylopsis species was structured phylogeographically during Quaternary climatic oscillations. The haplotype composition and results of analysis of molecular variance showed that the populations in Hokuriku were highly divergent, suggesting that they are long-term persistent populations arising from refugia during the Quaternary climatic oscillations. Refugial populations in Chugoku and Shikoku may have lost genetic diversity because of a bottleneck resulting from a small population size, followed by post-glacial range expansion. Pre-existing refugia may have been so small that the subsequent range expansion replaced the pre-existing genetic structure.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 157 , 501–518.     

The coincidence of climatic and species rarity: high risk to small-range species from climate change

Why do areas with high numbers of small-range species occur where they do? We found that, for butterfly and plant species in Europe, and for bird species in the Western Hemisphere, such areas coincide with regions that have rare climates, and are higher and colder areas than surrounding regions. Species with small range sizes also tend to occur in climatically diverse regions, where species are likely to have been buffered from extinction in the past. We suggest that the centres of high small-range species richness we examined predominantly represent interglacial relict areas where cold-adapted species have been able to survive unusually warm periods in the last ca 10 000 years. We show that the rare climates that occur in current centres of species rarity will shrink disproportionately under future climate change, potentially leading to high vulnerability for many of the species they contain.     

Baobabs and elephants in Kruger National Park: nowhere to hide

Baobab size class distributions were surveyed in the Limpopo National Park (LNP), Mozambique, and the Kruger National Park (KNP), South Africa. There are very few elephants in the LNP and the baobab population there had a reverse J-shaped size class distribution with many small baobabs. In contrast, the elephant-impacted baobab population of KNP displayed a mono-modal size-class distribution, with a lack in recruitment. Within KNP, elephant impact (percentage bark stripped up to the height of 3 m) decreased with increasing rockiness and slope steepness. We interpret this to suggest that steep rocky slopes are inaccessible to elephants and therefore these sites may act as a refuge for baobabs. In such inaccessible areas, the baobab population has a similar size-class distribution to that of the populations in the LNP. However, these baobab refugia are restricted in the northern KNP landscape and are therefore probably not large enough to sustain a viable baobab population.     

The biogeographical assignment of a west Kenyan rain forest remnant: further evidence from analysis of its reptile fauna

Aim The Kakamega Forest, western Kenya, has been biogeographically assigned to both lowland and montane forest biomes, or has even been considered to be unique. Most frequently it has been linked with the Guineo‐Congolian rain forest block. The present paper aims to test six alternative hypotheses of the zoogeographical relationships between this forest remnant and other African forests using reptiles as a model group. Reptiles are relatively slow dispersers, compared with flying organisms (Aves and Odonata) on which former hypotheses have been based, and may thus result in a more conservative biogeographical analysis. Location Kakamega Forest, Kenya, Sub‐Saharan Africa. Methods The reptile diversity of Kakamega Forest was evaluated by field surveys and data from literature resources. Faunal comparisons of Kakamega Forest with 16 other African forests were conducted by the use of the ‘coefficient of biogeographic resemblance’ using the reptile communities as zoogeographic indicators. Parsimony Analysis of Endemism and Neighbour Joining Analysis of Endemism were used to generate relationship trees based on an occurrence matrix with paup *. Results The analysis clearly supports the hypothesis that the Kakamega Forest is the easternmost fragment of the Guineo‐Congolian rain forest belt, and thus more closely related to the forests of that Central–West African complex than to any forest further east, such as the Kenyan coastal forests. Many Kenyan reptile species occur exclusively in the Kakamega Forest and its associated forest fragments. Main conclusions The Kakamega Forest is the only remnant of the Guineo‐Congolian rain forest in the general area. We assume that the low degree of resemblance identified for the Guineo‐Congolian forest and the East African coastal forest reflect the long history of isolation of the two forest types from each other. Kenyan coastal forests may have been historically connected through forest ‘bridges’ of the southern highlands with the Congo forest belt, allowing reptile species to migrate between them. The probability of a second ‘bridge’ located in the region of southern Tanzanian inselbergs is discussed. Although not particularly rich in reptile species, the area should be considered of high national priority for conservation measures.     

Genetic divergences pre-date Pleistocene glacial cycles in the New Zealand speckled skink, Oligosoma infrapunctatum

Aim To examine the hypothesis raised by Graham S. Hardy that Pleistocene glacial cycles suffice to explain divergence among lineages within the endemic New Zealand speckled skink, Oligosoma infrapunctatum Boulenger. Location Populations were sampled from across the entire range of the species, on the North and South Islands of New Zealand. Methods We sequenced the mitochondrial genes ND2 (550 bp), ND4 + tRNAs (773 bp) and cytochrome b (610 bp) of 45 individuals from 21 locations. Maximum likelihood, maximum parsimony and Bayesian methods were used for phylogenetic reconstruction. The Shimodaira–Hasegawa test was used to examine hypotheses about the taxonomic status of morphologically distinctive populations. Results Our analysis revealed four strongly supported clades within O. infrapunctatum. Clades were largely allopatric, except on the west coast of the South Island, where representatives from all four clades were found. Divergences among lineages within the species were extremely deep, reaching over 5%. Two contrasting phylogeographical patterns are evident within O. infrapunctatum. Main conclusions The deep genetic divisions we found suggest that O. infrapunctatum is a complex of cryptic species which diverged in the Pliocene, contrary to the existing Pleistocene‐based hypothesis. Although Pleistocene glacial cycles do not underlie major divergences within this species, they may be responsible for the shallower phylogeographical patterns that are found within O. infrapunctatum, which include a radiation of haplotypes in the Nelson and Westland regions.     

Historical climate modelling predicts patterns of current biodiversity in the Brazilian Atlantic forest

Aim We aim to propose validated, spatially explicit hypotheses for the late Quaternary distribution of the Brazilian Atlantic forest, and thereby provide a framework for integrating analyses of species and genetic diversity in the region. Location The Atlantic forest, stretching along the Brazilian coast. Methods We model the spatial range of the forest under three climatic scenarios (current climate, 6000 and 21,000 years ago) with BIOCLIM and MAXENT. Historically stable areas or refugia are identified as the set of grid cells for which forest presence is inferred in all models and time projections. To validate inferred refugia, we test whether our models are matched by the current distribution of the forest and by fossil pollen data. We then investigate whether the location of inferred forest refugia is consistent with current patterns of species endemism and existing phylogeographical data. Results Forest models agree with pollen records and predict a large area of historical forest stability in the central corridor (Bahia), as well as a smaller refuge (Pernambuco) along the Brazilian coast, matching current centres of endemism in multiple taxa and mtDNA diversity patterns in a subset of the species examined. Less historical stability is predicted in coastal areas south of the Doce river, which agrees with most phylogeographical studies in that region. Yet some widely distributed taxa show high endemism in the southern Atlantic forest. This may be due to limitations of the modelling approach, differences in ecology and dispersal capability, historical processes not contemplated by the current study or inadequacy of the available test data sets. Main conclusions Palaeoclimatic models predict the presence of historical forest refugia in the Atlantic rain forest and suggest spatial variation in persistence of forests through the Pleistocene, predicting patterns of biodiversity in several local taxa. The results point to the need for further studies to document genetic and species endemism in the relatively poorly known and highly impacted areas of Atlantic rain forests of north‐eastern Brazil.     

Are Polyommatus hispana and Polyommatus slovacus bivoltine Polyommatus coridon (Lepidoptera: Lycaenidae)? The discriminatory value of genetics in taxonomy

Taxonomic confusion exists in several sibling species groups. The Polyommatus coridon species complex (Chalk Hill Blues) serves as a model group of sibling species in which genetic analyses provide suitable means for taxonomic clarification. We studied the allozyme patterns of the two described bivoltine species of this complex, Polyommatus hispana and Polyommatus slovacus, and compared them to the two genetic lineages of the univoltine P. coridon. P. hispana is well distinguished from P. coridon (genetic distance: 0.081), and most probably is a sibling species that has evolved during glacial isolation on the Iberian Peninsula. P. slovacus is genetically indistinguishable from the eastern, Pontic–Mediterranean lineage of P. coridon; therefore we suggest that it represents a local bivoltine population only. Since the spring generation of P. slovacus was much less common than the summer generation and showed less genetic diversity, it is probable that uni-/bivoltinism is a dimorphism affecting only part of the whole population. We suggest that the higher genetic diversity of the second generation may be a consequence of gene flow from adjacent single-brooded populations.     

Reproductive ecology of Rhododendron ponticum (Ericaceae) in relict Mediterranean populations

In the southern Iberian Peninsula, Rhododendron ponticum occurs in restricted and vulnerable populations as a Tertiary relict. Population structure and the main phases of the reproductive process were examined in order to shed light on recruitment patterns and limitations. Rhododendron ponticum flowers are self-compatible and attract a diverse array of insects, which are responsible for a considerable number of seeds set in the populations. Nevertheless, only adults form populations, whilst seedlings are scarce and saplings virtually absent (only two juveniles out of 2489 adults sampled). Non-specialized vegetative multiplication by layering was observed. Recruitment failure seems to depend on the scarcity of safe microsites, which are free from drought, for seedling establishment. The observations contrast with R. ponticum 's reputation as an aggressive invader in temperate Atlantic areas. It is proposed that the species shows a variable balance between sexual reproduction and vegetative multiplication depending on environmental conditions. At present, only the latter seems to be prevailing in relict populations in the Iberian Peninsula. This flexible reproductive strategy is also discussed as a mechanism allowing persistence during geological climatic oscillations.  © The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 140 , 297–311.