Species delimitation and biogeography of the gnatcatchers and gnatwrens (Aves: Polioptilidae)

Molecular phylogeny and diversification of a widespread Neotropical rainforest bird group: The Buff-throated Woodcreeper complex, Xiphorhynchus guttatus/susurrans (Aves: Dendrocolaptidae)

Nutrient enrichment is increasingly affecting many tropical ecosystems, but there is no information on how this affects tree biodiversity. To examine dynamics in vegetation structure and tree species biomass and diversity, we annually remeasured tree species before and for six years after repeated additions of nitrogen (N) and phosphorus (P) in permanent plots of abandoned pasture in Amazonia. Nitrogen and, to a lesser extent, phosphorus addition shifted growth among woody species. Nitrogen stimulated growth of two common pioneer tree species and one common tree species adaptable to both high- and low-light environments, while P stimulated growth only of the dominant pioneer tree Rollinia exsucca (Annonaceae). Overall, N or P addition reduced tree assemblage evenness and delayed tree species accrual over time, likely due to competitive monopolization of other resources by the few tree species responding to nutrient enrichment with enhanced establishment and/or growth rates. Absolute tree growth rates were elevated for two years after nutrient addition. However, nutrient-induced shifts in relative tree species growth and reduced assemblage evenness persisted for more than three years after nutrient addition, favoring two nutrient-responsive pioneers and one early-secondary tree species. Surprisingly, N + P effects on tree biomass and species diversity were consistently weaker than N-only and P-only effects, because grass biomass increased dramatically in response to N + P addition. The resulting intensified competition probably prevented an expected positive N + P synergy in the tree assemblage. Thus, N or P enrichment may favor unknown tree functional response types, reduce the diversity of coexisting species, and delay species accrual during structurally and functionally complex tropical rainforest secondary succession.

Nutrient enrichment is increasingly affecting many tropical ecosystems, but there is no information on how this affects tree biodiversity. To examine dynamics in vegetation structure and tree species biomass and diversity, we annually remeasured tree species before and for six years after repeated additions of nitrogen (N) and phosphorus (P) in permanent plots of abandoned pasture in Amazonia. Nitrogen and, to a lesser extent, phosphorus addition shifted growth among woody species. Nitrogen stimulated growth of two common pioneer tree species and one common tree species adaptable to both high- and low-light environments, while P stimulated growth only of the dominant pioneer tree Rollinia exsucca (Annonaceae). Overall, N or P addition reduced tree assemblage evenness and delayed tree species accrual over time, likely due to competitive monopolization of other resources by the few tree species responding to nutrient enrichment with enhanced establishment and/or growth rates. Absolute tree growth rates were elevated for two years after nutrient addition. However, nutrient-induced shifts in relative tree species growth and reduced assemblage evenness persisted for more than three years after nutrient addition, favoring two nutrient-responsive pioneers and one early-secondary tree species. Surprisingly, N + P effects on tree biomass and species diversity were consistently weaker than N-only and P-only effects, because grass biomass increased dramatically in response to N + P addition. The resulting intensified competition probably prevented an expected positive N + P synergy in the tree assemblage. Thus, N or P enrichment may favor unknown tree functional response types, reduce the diversity of coexisting species, and delay species accrual during structurally and functionally complex tropical rainforest secondary succession.

The evolutionary history of vines in a neotropical biodiversity hotspot: Phylogenomics and biogeography of a large passion flower clade (Passiflora section Decaloba)

The Middle East contains a great diversity of Capoeta species, but their taxonomy remains poorly described. We used mitochondrial history to examine diversity of the algae‐scraping cyprinid Capoeta in Iran, applying the species‐delimiting approaches General Mixed Yule‐Coalescent (GMYC) and Poisson Tree Process (PTP) as well as haplotype network analyses. Using the BEAST program, we also examined temporal divergence patterns of Capoeta. The monophyly of the genus and the existence of three previously described main clades (Mesopotamian, Anatolian‐Iranian, and Aralo‐Caspian) were confirmed. However, the phylogeny proposed novel taxonomic findings within Capoeta. Results of GMYC, bPTP, and phylogenetic analyses were similar and suggested that species diversity in Iran is currently underestimated. At least four candidate species, Capoeta sp4, Capoeta sp5, Capoeta sp6, and Capoeta sp7, are awaiting description. Capoeta capoeta comprises a species complex with distinct genetic lineages. The divergence times of the three main Capoeta clades are estimated to have occurred around 15.6–12.4 Mya, consistent with a Mio‐Pleistocene origin of the diversity of Capoeta in Iran. The changes in Caspian Sea levels associated with climate fluctuations and geomorphological events such as the uplift of the Zagros and Alborz Mountains may account for the complex speciation patterns in Capoeta in Iran.

The taxonomic placements of Chaenomeles Lindl. (Rosaceae) and their intrageneric species have long been controversial. This research aims to explore the palynomorphological characters of all Chaenomeles extant species in detail and to compare the results with phylogenetic relationships and the taxonomic classification scheme. The pollen morphology of 30 individuals of six taxa of Chaenomeles was investigated using both light microscopy and scanning electron microscopy. The pollens were measured, observed and statistically analyzed for 12 quantitative features and 2 qualitative ones. The study revealed that the Chaenomeles pollens are monad, tri-colporate, medium in size (P = 32.78–42.74 μm, E = 30.42–36.31 μm) and prolatespheroidal to subprolate in shape (P/E = 0.98–1.35). Based on exine ornamentation observed under SEM, two sexine sculpture types (type I—striate with microperforations, type II—striate with macroperforations) and two subtypes (twisted-striate, reticulate-striate) were recognized in the genus. Statistical analysis identified some pollen characteristics with diagnostic importance, including pollen shape, colpus dimension, length or direction of striae and diameter of perforation. These characteristics may have diagnostic and taxonomic value for the genus Chaenomeles and the family Rosaceae. An artificial key to studied species, based on pollen micromorphological attributes, is also provided. The obtained result was basically consistent with that of molecular studies published earlier. This study, for the first time, provides palynological evidence for the hybrid origin hypothesis of C. sinensis and supports the placement of this species in the monotypic genus Pseudocydonia.

Patterns of plant diversity and plant–environmental relationships across three riparian corridors

This research focuses on the urban tree species population and diversity within Ibadan metropolis as a means of creating biodiversity database for the urban centre in South west, Nigeria.This was determined by assessing urban forest tree abundance, species diversity and growth yield.All trees with diameter at breast height (dbh) ≥ 10 cm were identified, dbh measured and their frequencies taken in all the area enumerated within Ibadan.There are 155 tree stems belonging to 26 families and 54 tree species within Ibadan built-up areas and 101 tree stems belonging to 16 families and 19 tree species in peri-urban centre of Ibadan.The two most abundant species and families were Delonix regia of Fabaceae family and Terminalia ivorensis of Combretaceae family (18 and 17 stems) respectively while Fabaceae family has (7 species).The value of the Shannon's max diversity index (H max ) of (3.99 and 2.94), Shannon-Wiener diversity index (3.35 and 2.48) and species evenness 0.84 were the same for peri-urban centre, while the growth variable were basal area and volume of (22.8m 2 and 18.5m 2 ) and (284.8m 3 and 275.3m 3 ) respectively.This study provide information on the level of tree species biodiversity due to infrastructure development that has reduced forest cover within the built-up areas of Ibadan which can expose the city to lot of environmental hazard.

Ruagea (Meliaceae) comprises c. 15 species of small or medium-sized trees distributed in Central and South America, predominantly in montane rain forest and cloud forest of the Andes. The taxonomic position of Ruagea has changed several times in the past, and it was previously included in Guarea. Ruagea is currently accepted as a separate genus based on morphology and molecular phylogenetic analyses at the family level. However, its monophyly has not been accurately tested, and phylogenetic relationships among species are still largely unknown. In addition, delimitation of species boundaries is not straightforward due to morphological diversity within species. Here, we present the first phylogenetic reconstruction of Ruagea based on two nuclear ribosomal (ITS, ETS) and two plastid DNA regions (rps4-trnT, psbA-trnH). Our results show that Ruagea is monophyletic and composed of four main clades (A, B, C and D). Clade D, comprising the Ecuadorian endemic R. membranacea and a potentially new species from Colombia, is sister to the rest of the genus. Our results demonstrate that R. membranacea and R. insignis are monophyletic and provide support for the recognition of two new species with divergent morphologies. The delimitation of the remaining species remains unresolved as they are recovered as either poly- or paraphyletic. Our results highlight the complexity of the taxonomy of Ruagea, as found in other rainforest taxa, and the need for further detailed analyses to delimit these taxa. This study provides the first and most extensive phylogenetic analysis of the genus so far, representing a contribution towards understanding the evolutionary history of Ruagea.

The role of sacred forest/sacred groves in the conservation of biodiversity is well recognised and documented. Despite the importance of sacred forests in conservation, data of flora species composition and diversity in many sacred forests still remain scanty. The study was conducted to provide baseline data on tree species composition and diversity of Ipinu-Igede sacred forest with a view to promote the role of sacred forest in flora conservation in the area. Systematic sampling technique was adopted for the study. A base line transect of 2 km long was established and five (5) other transects 2 km long were laid at regular interval of 500 km apart. On each transect, 4 sampling plots of 50 mx50 m were established at a regular interval of 500m apart. Within the 50 m x50 m plots, trees with diameter at breast height (DBH)≥10 cm were identified and enumerated. Species Important Value Index (IVI), species richness, species evenness and species diversity were estimated. A total number of 50 tree species in 19 families were recorded. Cola gigantea was the most important tree species with IVI of 14.56, this was followed by Harungana madagascariensis with 13.14. Caesalpinioideae was the dominant family with 6 species, 48.15% of the families were represented by only one species. The species richness was D=9.436, Species Evenness was E´=0.7668 and species diversity was H=3.646. Thirty percent (30%) of the tree species were in the DBH class of 1-40cm indicating good regeneration status of the sacred forest. Acknowledgement of the traditional practices by scientists and other actors in natural resources conservation will help in promoting forest conservation.

Socioeconomic and spatial inequalities of street tree abundance, species diversity, and size structure in New York City

This study examined differences in stand structure, tree species richness, and tree species diversity in relation to population density in Kampong Thom Province, Cambodia. Tree data were obtained from a 1997 forest inventory involving 60 clusters (540 plots) systematically distributed over 30% of the provincial forest area. Spatially referenced population data were obtained from the 1998 national population census. The average number of trees per cluster was 356/ha, the average basal area, 23 m2/ha, the average stand volume, 217 m3/ha, and the average aboveground biomass, 273 Mg/ha for all trees of DBH 10 cm and larger. The average species richness per cluster was 37 species, while average species diversity was measured as 0.916 using Simpson’s index and 2.98 by Shannon’s index. Significant negative correlations were generally found between population density surrounding clusters and tree density, basal area, stand volume, aboveground biomass, and species richness and diversity for three examined diameter classes (DBH of 10–30, ≥30, and ≥10 cm). As the distance from clusters for calculating population density increased, the correlation levels increased up to 5 or 7 km, depending on the variables and diameter class, and then stayed relatively constant for stand structure variables and decreased for species richness and diversity. The results indicate that evidence of disturbance was more pronounced at higher population density up to around 5 to 7 km. We suggest that introduction of greater controls on human disturbance should be a high priority for resource management and conservation in Kampong Thom Province and, presumably, Cambodia as a whole.

Tripodanthus consists of three species that are endemic to South America. While T. acutifolius and T. flagellaris have east-west distributions in tropical and subtropical South America, T. belmirensis is restricted to its type locality in the region of Belmira, Colombia. The objective of the present study was to reconstruct the phylogeny of the genus using molecular markers (nrDNA ITS and plastid atpB-rbcL and trnL-F regions) and to examine morphological characters in the variable species T. acutifolius. A total of 23 individuals of Tripodanthus, representing all species currently recognized in the genus, were sampled in the molecular phylogeny, while 73 individuals were measured for the morphological component of this study. Phylogenetic analyses of the combined ITS and plastid markers reconstructed two main clades within T. acutifolius that correspond to two geographic areas: the Andes and the eastern region of southern South America. This analysis also yielded a monophyletic T. flagellaris, although no geographic structure was obtained within this clade. Tripodanthus belmirensis and T. acutifolius together formed a clade that was sister to T. flagellaris. A principal component analysis of 70 individuals of T. acutifolius showed great variability in leaf morphological characters, leading to overlapping clusters for Andean and eastern mistletoes. The morphologically variable T. acutifolius was not well supported as monophyletic and possessed overlapping morphological features with T. belmirensis, calling into question whether T. belmirensis should be recognized as a distinct species. Keywords—Amphiphagy, Andes, Brazil, biogeography, host plant, parasitic plant, Santalales.

Phylogenomic data resolve higher-level relationships within South American Liolaemus lizards

Research Highlights: Using a long-term dataset on temperate forests in South Korea, we established the interrelationships between tree species and structural diversity and forest productivity and stability, and identified a strong, positive effect of structural diversity, rather than tree species diversity, on productivity and stability. Background and Objectives: Globally, species diversity is positively related with forest productivity. However, temperate forests often show a negative or neutral relationship. In those forests, structural diversity, instead of tree species diversity, could control the forest function. Materials and Methods: This study tested the effects of tree species and structural diversity on temperate forest productivity. The basal area increment and relative changes in stand density were used as proxies for forest productivity and stability, respectively. Results: Here we show that structural diversity, but not species diversity, had a significant, positive effect on productivity, whereas species diversity had a negative effect, despite a positive effect on diversity. Structural diversity also promoted fewer changes in stand density between two periods, whereas species diversity showed no such relation. Structurally diverse forests might use resources efficiently through increased canopy complexity due to canopy plasticity. Conclusions: These results indicate reported species diversity effects could be related to structural diversity. They also highlight the importance of managing structurally diverse forests to improve productivity and stability in stand density, which may promote sustainability of forests.