Plant Species Diversity In Forests Research Articles

Light‐demanding tree species are more susceptible to lianas than shade‐tolerant tree species in a subtropical secondary forest

Abstract Tree‐tree competition has been widely studied as a mechanism responsible for maintaining forest plant species diversity. Other common plant types, such as lianas, may influence tree species competition. Previous studies reported the negative effects of lianas on trees; however, variation in susceptibility to lianas among tree species and the species‐specificity of liana species for tree hosts remain unclear. If lianas have species‐specific interactions with trees, based either on tree or liana species identity, then lianas may influence tree‐tree interactions by altering tree species‐specific competitiveness. We surveyed 5676 lianas (DBH ≥ 0.5 cm) and 61,538 trees (DBH ≥ 1 cm) in a 12‐ha subtropical secondary forest plot to assess liana‐tree interactions. We tested variation among the 20 most common tree species in their susceptibility to lianas, including whether light‐demanding and shade‐tolerant tree species differed. We quantified liana‐tree network structure and evaluated the specificity between the 20 most common tree species and the 15 most common liana species. We expected that: (1) tree species would vary in their susceptibility to lianas, and the extent of this variation would be predicted by tree shade‐tolerance; and (2) liana species would have distinct species‐specific interactions with host trees. Tree species differed greatly in their susceptibility to lianas, with some tree species accumulating many more lianas than others. Light‐demanding tree species particularly had greater susceptibility to lianas than shade‐tolerant tree species. Both the liana‐tree network structure and the interaction intensity between the 15 liana species and 20 tree species showed distinct specialization of liana‐tree interactions. Synthesis. Variation in trees species' susceptibility to lianas implies that lianas may alter tree species‐specific competitive abilities by disproportionately affecting some tree species more than others. In contrast to studies in neotropical forests, light‐demanding tree species were more susceptible to lianas than shade‐tolerant tree species, suggesting that lianas could reduce light‐demanding tree performance in this forest. The distinct species specialization between liana and tree species suggests that increases in the relative abundance of liana species, which is occurring in many forests, may alter the tree community composition by reducing the relative abundance of preferred host tree species.

Main environmental variables influencing the abundance of plant species under risk category

Determining climatic and physiographic variables in Mexico's major ecoregions that are limiting to biodiversity and species of high conservation concern is essential for their conservation. Yet, at the national level to date, few studies have been performed with large data sets and cross-confirmation using multiple statistical analyses. Here, we used 25 endemic, rare and endangered species from 3610 sampling points throughout Mexico and 25 environmental attributes, including average precipitation for different seasons of the year, annual dryness index, slope of the terrain; and maximum, minimum and average temperatures to test our hypothesis that these species could be assessed with the same weight among all variables, showing similar indices of importance. Our results using principal component analysis, covariation analysis by permutations, and random forest regression showed that summer precipitation, length of the frost-free period, spring precipitation, winter precipitation and growing season precipitation all strongly influence the abundance of tropical species. In contrast, annual precipitation and the balance at different seasons (summer and growing season) were the most relevant variables on the temperate region species. For dry areas, the minimum temperature of the coldest month and the maximum temperature of the warmest month were the most significant variables. Using these different associations in different climatic regions could support a more precise management and conservation plan for the preservation of plant species diversity in forests under different global warming scenarios.

Selection of nuclear microsatellite loci for specific identification of Larix gmélinii Rupr. and comparison of genetic profiles of Larix to solve agricultural problems

Preservation and study of forest plant species diversity is one of the fundamental challenges of modern botany, genetics, and dendrology. Genetic structure determines variability and controls adaptation mechanisms, letting every population adapt to environmental conditions. The most topical issue is genetic study of valuable forest species to ensure their integrity, specific identification, and control over wood origin. One of such environmentally and economically important coniferous species in our country is larch (Larix). Currently, there is a problem to use azonal larch species for reforestation in Russia, particularly in the Russian Far East. In this regard, selection of genetic markers that let us detect differences between Larix gmélinii Rupr. and Larix sibírica Ledeb. and their subspecies is a crucial and relevant task.

散布後種子捕食と森林の種多様性( 菌類・植食者との相互作用が作り出す森林の種多様性)

散布後種子捕食と森林の種多様性( 菌類・植食者との相互作用が作り出す森林の種多様性)

Roles of non‐native species in large‐scale regeneration of moist tropical forests on anthropogenic grassland

AbstractThis paper presents a new synthesis of the role of native and non‐native species in diverse pathways and processes that influence forest regeneration on anthropogenic grassland in the moist tropics. Because of altered species composition, abiotic conditions and landscape habitat mosaics, together with human interventions, these successional pathways differ from those seen in pre‐clearing forests. However, representation of different functional life forms of plant (tree, vine, grass, herb and fern) and animal (frugivorous seed disperser, granivorous seed predator, seedling herbivore and carnivore) shows consistent global variation among areas of pasture, intact forest, and post‐grassland regrowth. Biotic webs of interaction involve complex indirect influences and feedbacks, which can account for wide observed variation in regeneration trajectories over time. Important processes include: limitation of tree establishment by dense grasses; recruitment and growth of pioneer pasture trees (shading grasses and facilitating bird‐assisted seed dispersal); and smothering of trees by vines. In these interactions, species’ functional roles are more important than their biogeographic origins. Case studies in eastern Australia show native rain forest plant species diversity in all life forms increasing over time when pioneer trees are non‐native (e.g., Cinnamomum camphora, Solanum mauritianum), concurrent with decreased grass and fern cover and increased abundance of trees and vine tangles. The global literature shows both native and non‐native species facilitating and inhibiting regeneration. However conservation goals are often targeted at removing non‐native species. Achieving large‐scale tropical forest restoration will require increased recognition of their multiple roles, and compromises about allocating resources to their removal.

The analysis of spatio-temporal forest changes (1775–2000) in Flanders (northern Belgium) indicates habitat-specific levels of fragmentation and area loss

Introduction Spatio-temporal forest changes can have a progressive negative impact on the habitat of species that need forest continuity, i.e. the continuous presence of forest. Long-term species data that demonstrate such an impact are often not available. Instead we applied a spatial analysis on maps of the historical and present-day forests, by calculating landscape indices that explain forest plant species diversity.

A spatially explicit empirical model on actual and potential ancient forest plant diversity in a fragmented landscape

Spatio-temporal forest cover changes often cause a change of forest plant species diversity. Slow colonizing ancient forest plant species (AFS) can be negatively affected, as they depend to a certain degree on the continuity of the forest cover in space and time. The implementation of conservation and restoration strategies for AFS can be supported by a map that represents the actual AFS diversity of the current forest, as well as the potential AFS diversity that open land can achieve when converted to forest. To create such a map for Flanders (northern Belgium), an empirical model was constructed using spatially explicit data on habitat suitability and continuity. The model calculated a high AFS diversity for suitable mesophilous sites covered by forest in 1775 and in the early 20th century. Sites near a concave edge of a forest patch in 2000, either inside or outside forest, were also rated high. This is the first operational landscape model on AFS diversity that can be used to select hotspots of AFS diversity in the present-day forest and sites with a high restoration potential in the open landscapes. Application of the AFS diversity map on a local scale should include additional information on linear landscape elements, soil conditions and forest management, as we assume that these factors account for a high proportion of the unexplained deviance.

High plant species richness indicates management-related disturbances rather than the conservation status of forests

There is a wealth of smaller-scale studies on the effects of forest management on plant diversity. However, studies comparing plant species diversity in forests with different management types and intensity, extending over different regions and forest stages, and including detailed information on site conditions are missing. We studied vascular plants on 1500 20m×20m forest plots in three regions of Germany (Schwäbische Alb, Hainich-Dün, Schorfheide-Chorin). In all regions, our study plots comprised different management types (unmanaged, selection cutting, deciduous and coniferous age-class forests, which resulted from clear cutting or shelterwood logging), various stand ages, site conditions, and levels of management-related disturbances. We analyzed how overall richness and richness of different plant functional groups (trees, shrubs, herbs, herbaceous species typically growing in forests and herbaceous light-demanding species) responded to the different management types. On average, plant species richness was 13% higher in age-class than in unmanaged forests, and did not differ between deciduous age-class and selection forests. In age-class forests of the Schwäbische Alb and Hainich-Dün, coniferous stands had higher species richness than deciduous stands. Among age-class forests, older stands with large quantities of standing biomass were slightly poorer in shrub and light-demanding herb species than younger stands. Among deciduous forests, the richness of herbaceous forest species was generally lower in unmanaged than in managed forests, and it was even 20% lower in unmanaged than in selection forests in Hainich-Dün. Overall, these findings show that disturbances by management generally increase plant species richness. This suggests that total plant species richness is not suited as an indicator for the conservation status of forests, but rather indicates disturbances.

Relationship between diversity of forest plant species and environmental gradient in eastern mountainous area of Heilongjiang Province, China

Twenty-three secondary forest communities with different structure were selected in Mao’er Mountain National Park of Heilongjiang Province, China to study the relationship between diversity of forest plant species and environmental gradient. The forest plant species diversity was analyzed by the diversity index, and the environmental factors was quantified by the method of Whittaker’s quantification of environmental gradient. Meanwhile, β-diversity indexes of communities were calculated with similar measurements. The results showed that the Shannon-wiener diversity index of forest plant species increased with the increase of the environmental gradient, and the β-diversity indexes of communities showed a liner increase along with the change of environmental gradient.

Soil Properties and Soil Nitrogen Dynamics of Prairie-like Forest Openings and Surrounding Forests in Kentucky's Knobs Region

Herbaceous communities located within forest openings increase plant species diversity of forests in the Knobs Region of Kentucky. Although these grass-dominated communities are protected and managed for rare plant species conservation, it is unclear how soil conditions may delineate the grassland-forest boundary. We compared soil chemical and physical properties and soil nitrogen pools and transformations of three forest openings with those in the surrounding forest and the wooded edge separating the grassland and forest communities. Soil pH, extractable cations, bulk density and silt content were higher in openings compared to forest soils and extractable phosphorus was lower. In forest-opening grasslands, total soil nitrogen and the availability and production of plant-available N were 25 to 50% of levels in adjacent forest. Soils of the woody edge were similar to the surrounding forest. Our results suggest that the presence of these calcareous glade openings is highly correlated with edaphic conditions, so that efforts to expand rare plant habitat may be constrained by the distinct soils of these forest openings.