Patterns of diversity and range size of selected plant groups along an elevational transect in the Bolivian Andes

Patterns of point, -, and -diversity, and of an index of range size were studied for Acanthaceae, Araceae, Bromeliaceae, Melastomataceae, Palmae, and Pteridophyta in 204 vegetation plots of 400 m² along an elevational gradient in humid montane forest at 220–3950 m in central Bolivia. Zonal forest point-diversity (mean species number per plot) and -diversity (extrapolated total species number) showed either hump-shaped curves or constant values from lowlands to mid-elevations, followed by a steep decline. These patterns correspond to the hypothesis of maximum diversity at intermediate levels of productivity, while for pteridophytes and epiphytic Bromeliaceae they also fitt a null-model of random distribution within bounded geographical ranges. The ratio of point to -diversity was surprisingly constant across study groups and elevation with values of 0.2–0.4. Range size index (mean inverse range size of all species recorded at a given elevation) either increased with elevation, showed hump-shaped patterns, or remained roughly constant. Non-zonal habitats (ravines, ridge-tops, rock faces, roadsides, pastures) contributed significantly to overall species number for terrestrial herbs and shrubs of Bromeliaceae, Melastomataceae, and Pteridophyta, but not for Acanthaceae, Araceae, and epiphytic taxa. With few exceptions, endemism was most pronounced in zonal forests. These results imply that conservation measures should focus on zonal forests in a few large reserves at low and mid-elevations and in many smaller reserves at higher elevations.     

Diversity and endemism of Murinae rodents in Thai limestone karsts

This study aims to investigate the species diversity of rodents living in karst ecosystems of Thailand. A survey has been conducted throughout Thailand, 122 karsts sampled and 477 Murinae rodents live-trapped. Phylogenetic reconstructions were carried out using two mitochondrial markers (cytb, COI). A sequence-based species delimitation method completed by the analysis of the level of genetic divergence was then applied to define species boundaries within our dataset. The phylogenetic position of Niviventer hinpoon was also investigated and sequences obtained from the holotype specimen of this species were used to reliably identify samples of N. hinpoon. A total of 12 described Murinae species, corresponding to 17 deeply divergent genetic lineages, were encountered in limestone karsts of Thailand. Our study revealed an important genetic diversity within the traditionally recognized species Maxomys surifer (four highly divergent genetic lineages), Leopoldamys neilli (two highly divergent genetic lineages) and Berylmys bowersi (two highly divergent genetic lineages). These species could be considered as species complex and require further taxonomic work. This study also provides valuable information on the distribution of the two rodent species endemic to limestone karsts of Thailand, L. neilli and N. hinpoon. Leopoldamys neilli was the most abundant species encountered in Thai karsts during our survey. However, L. neilli specimens from western Thailand are genetically highly divergent from the remaining populations of L. neilli and could represent a separate species. Niviventer hinpoon, phylogenetically closely related to N. fulvescens, is much rarer and its distribution limited to central Thailand. Most of the other captured species are typically associated with forest ecosystems. This study suggests that limestone karsts play a key role in the preservation of the rodent species endemic to such habitat, but they would also provide refuges for the forest-dwelling Murinae rodents in deforested regions.     

The geography of diversification in mutualistic ants: a gene's-eye view into the Neogene history of Sundaland rain forests

We investigate the geographical and historical context of diversification in a complex of mutualistic Crematogaster ants living in Macaranga trees in the equatorial rain forests of Southeast Asia. Using mitochondrial DNA from 433 ant colonies collected from 32 locations spanning Borneo, Malaya and Sumatra, we infer branching relationships, patterns of genetic diversity and population history. We reconstruct a time frame for the ants' diversification and demographic expansions, and identify areas that might have been refugia or centres of diversification. Seventeen operational lineages are identified, most of which can be distinguished by host preference and geographical range. The ants first diversified 16-20 Ma, not long after the onset of the everwet forests in Sundaland, and achieved most of their taxonomic diversity during the Pliocene. Pleistocene demographic expansions are inferred for several of the younger lineages. Phylogenetic relationships suggest a Bornean cradle and major axis of diversification. Taxonomic diversity tends to be associated with mountain ranges; in Borneo, it is greatest in the Crocker Range of Sabah and concentrated also in other parts of the northern northwest coast. Within-lineage genetic diversity in Malaya and Sumatra tends to also coincide with mountain ranges. A series of disjunct and restricted distributions spanning northern northwest Borneo and the major mountain ranges of Malaya and Sumatra, seen in three pairs of sister lineages, further suggests that these regions were rain-forest refuges during drier climatic phases of the Pleistocene. Results are discussed in the context of the history of Sundaland's rain forests.     

Postglacial migration supplements climate in determining plant species ranges in Europe

The influence of dispersal limitation on species ranges remains controversial. Considering the dramatic impacts of the last glaciation in Europe, species might not have tracked climate changes through time and, as a consequence, their present-day ranges might be in disequilibrium with current climate. For 1016 European plant species, we assessed the relative importance of current climate and limited postglacial migration in determining species ranges using regression modelling and explanatory variables representing climate, and a novel species-specific hind-casting-based measure of accessibility to postglacial colonization. Climate was important for all species, while postglacial colonization also constrained the ranges of more than 50 per cent of the species. On average, climate explained five times more variation in species ranges than accessibility, but accessibility was the strongest determinant for one-sixth of the species. Accessibility was particularly important for species with limited long-distance dispersal ability, with southern glacial ranges, seed plants compared with ferns, and small-range species in southern Europe. In addition, accessibility explained one-third of the variation in species' disequilibrium with climate as measured by the realized/potential range size ratio computed with niche modelling. In conclusion, we show that although climate is the dominant broad-scale determinant of European plant species ranges, constrained dispersal plays an important supplementary role.     

Vascular Plant Species Inventory of a Philippine Lowland Rain Forest and its Conservation Value

The Philippines are one of the most important biodiveristy hotspots on earth. Due to the extraordinary rate of environmental destruction, leaving only 3% of the land with primary forest, this biodiversity is at high risk. Despite that situation information on Philippine forest vegetation is fragmentary and focused on trees. This study aimed at analysing forest remnants in the Leyte Cordillera on the Island of Leyte, and at evaluating their role as refuge to the largely destroyed lowland forest vegetation. A total of 49 plots (100 m² each) between 55 and 520 m a.s.l. were studied. All vascular plant species except epiphytes were included. Records include 685 taxa from 289 genera and 111 families, representing nearly 8% of the known Philippine vascular plant species. More than half (52%) of the species are Philippine endemics. A number of 41 tree species, or 6% of all taxa recorded, are included in the IUCN red list, either as vulnerable, endangered, or critically endangered. Life form composition was dominated by phanerophytes (65.3%), followed by lianas and chamaephytes (17.1 and 16.9%, respectively). The most common families were the Rubiaceae with 35 and the Euphorbiaceae with 32 species. All five Philippine dipterocarp forest types as well as the molave forest type were represented by typical tree species. The area provides an important gene bank of the highly threatened Philippine lowland forest vegetation and is of high value for biodiversity conservation. Additionally, it can play an important role as seed source of valuable tree species for the increasing initiatives to rehabilitate and reforest degraded land with native species.     

西双版纳地区六种林型地表蜘蛛多样性比较研究

为探索地表蜘蛛多样性及其变化与森林类型和管理方式的关系, 在西双版纳勐仑自然保护区选择热带季节雨林、石灰山季节雨林和山地常绿阔叶林, 在自然保护区附近选择人工纯林、胶茶群落和橡胶林, 共6种林型, 每种林型选择3块样带, 共设置研究样地18块, 分别于2006年12月上旬（雾凉季）、2007年3月下旬（干热季）和2007年7月上旬（雨季）, 以单位地表面积法收集地表蜘蛛的物种组成和数量数据, 并以蜘蛛种类和数量分布为属性进行典范对应分析（CCA）, 探讨不同类型植被与地表蜘蛛多样性的关系。共采集蜘蛛标本9 849头, 用于统计分析的成熟蜘蛛3 119头, 归属于30科, 其中幽灵蛛科、皿蛛科、球蛛科和小密蛛科是地表蜘蛛的优势类群。各林型科的数量为: 热带季节雨林24科, 石灰山季节雨林22科, 山地常绿阔叶林22科, 人工纯林20科, 胶茶群落21科, 橡胶林19科; 各林型特有科数量: 热带季节雨林2科, 山地常绿阔叶林2科, 橡胶林1科; 而仅在雨林中分布的科4个（占全部30个科的13.3%）, 仅在自然林中分布的科6个（20.0%）, 仅在人工林中分布的科1个（3.3%）。从蜘蛛的数量分布看, 个体密度在热带季节雨林显著高于其他5种林型; 橡胶林多样性指数和丰富度指数显著低于3种自然林, 而均匀度指数的最低值也同样在橡胶林出现。CCA分析和聚类分析的结果表明, 6种林型趋于分成2组, 即: 自然林和人工林; 在自然林中两种次生林的相似程度更高; 人工林中人工纯林（非橡胶林）与胶茶群落的相似程度更高。以上结果表明: （1）森林砍伐后种植人工林措施改变了该地区地表蜘蛛群落的物种分布格局; （2）蜘蛛多样性随着人为干扰程度增加有减少的趋势; （3）减少人为干扰和增加植被群落多样性（橡胶林中种植茶树）对保护和恢复物种多样性有重要意义。     

Species richness of gall-forming insects in a tropical rain forest: correlations with plant diversity and soil fertility

We tested two hypotheses to explain changes in species richness ofgall-forming insects. The first hypothesis proposes that gall-forming insectspecies richness increases as more potential host–plant species areavailable. The second hypothesis implies that soil fertility affects plantcolonization by gall-forming insects. Seven sites, representing strongdifferences in vegetation and soil were chosen at the Lacandona tropical rainforest region, Chiapas, Mexico. Overall, we found 1522 individual plantsbelonging to 340 different plant species. From this, we found gall-forminginsects on 737 (43.9%) plants and on 74 (22%) of total plant species. We found asignificant negative correlation between gall-forming insect species richnessand species richness of plants, which does not support the hypothesis that plantspecies richness is an important factor in generating the radiation ofgall-forming insects. Using phosphorus as an indicator of soil fertility, wefound the lowest number of plants with gall-forming insects and the smallestgall-forming insect load per individual plant in the more fertile soil(alluvial). In contrast, the highest number of plants with galls and the highestgall-forming insect load per plant were found at a savanna-like vegetationsite, where the poorest soil was recorded. These results did not support thesoil fertility hypothesis in terms of species richness, but did with respect toabundance of plants with galls.