| Plant functional groups (PFGs) link plant functional traits and environmental variations with great clarity. Most of the studies on PFGs of terrestrial ecosystems to date have concentrated on grasslands and forests.The PFGs concept has facilitated studies on complex plant communities. It allows us to describe an entire terrestrial ecosystem in a very finite number of distinct plant functional types instead of thousands of plant species, thus vastly simplifying studies on highly complex plant communities by reducing variables that require investigation phenomenally. Currently, the extent and width of researches on PFGs have far exceeded the PFGs concept itself. Indeed, researches on PFGs have evolved and coalesced into a self-sustaining academic discipline. The PFGs concept groups plant species into distinct clusters according to similarities in their functions and responses to environmental conditions. Plants respond to environmental conditions in various ways that are subject to specific circumstances, however, and their functional characteristics are far from absolute and simple, therefore different definitions and classification methods of PFGs exist. Many researchers have studied Plant Functional Types from different perspectives and on varying scales. Focused on differing topics, these studies are designed to answer a wide range of scientific questions in relation with PFGs. The processes and results of these studies can provide much insight into plant functional groups, thus significantly facilitating our comprehension of complex terrestrial ecosystems. The PFGs concept has by now permeated the entire filed of ecosystem ecology so thoroughly that researchers almost always use this concept while studying terrestrial ecosystems, either explicitly or implicitly. Consequently the application of the PFGs concept has been much broadened. Having conducted numerous studies on PFGs and thus accumulated large amounts of relevant data, researchers working on plant functional groups and related topics all over the world now need a universal, standardized, and unequivocal research protocol. Such a protocol will allow a comprehensive integration of research projects on PFGs globally, which in turn can provide a significant boost to future researches on PFGs and deepen our understanding of plant functional groups.Forest ecosystems are characterized by extraordinary structural complexity and phenomenal plant species richness. While making forest ecosystems fascinating, these characteristics complicate the task of understanding the interconnections and functions of forest plant species. Dividing the species rich and functionally complex vegetation of a forest ecosystem into plant functional types can significantly facilitate studies on the structure and functioning of such an ecosystem by vastly reducing variables that require investigation. Dominant species control the structure and functioning of a forest ecosystem. Delimiting plant functional types of a forest ecosystem according to dominant species, therefore, is a viable path to gaining a clear understanding of the functions, structural framework, and species distributions of such an ecosystem. Straddling the subtropical and warm-temperate zones of East China, the FuNiu Mountain National Natural Reserve is representative of north-south climatic transition zones. There is composed mainly of a few dominant species whose abundances clearly vary along altitudinal gradients. Using community ecology techniques, we investigated plant assemblages on both the north and south slopes of the FuNiu Mountain. Results of this investigation were used to calculate species importance values, which in turn were used to identify dominant species. In all, (1)thirty-seven tree species were studied. X2 test, together with association coefficient (AC) and percentage co-occurrence (PC), were used to measure interspecific associations of the dominant tree species. PFTs were defined according to interspecific associations and altitudinal distributions of the dominant species. Four dominant tree species are identified (Quercus variabilis, Q. glandulifera, Q. acutidentata, Pinus armandi), forming the basis of four PFTs. PFT1: Quercus variabilis, Quercus aliena, Aldizzia kalkora, Castanea seguinii(under 1000m);PFT2: Quercus glandulifera, Platycarya strobilacea, Pistacia chinensis(1100m~1400m); PFT3: Quercus acutidentata, Carpinus cordata, Toxicodendron vernicifluum(1400~1800m); PFT4: Pinus armandi, Pinus tabulaeformis, Abelia biflora, Betula platyphylla, Betula albo-sinensis(up 1800m). By analyzing dynamics of these plant functional types along moisture and temperature gradients, we have discovered that while these PFTs have similarities in several important morphological characteristics, they differ in many other vital morphological traits such as leaf size and phellem (cork) thickness. Some evolutionary connections and differentiations also appear to exist among these PFTs. (2)Highly responsive to changes in environmental conditions, herbaceous plants are very useful to the study of vegetation-environment dynamics.Use the same means, seven PFTs were confirmed:â… "with people",â…¡"mountain",â…¢"wet",â…£"drought",â…¤"gap",â…¥"foundation",â…¦" primitive type. " The seven types of herbs functional group basically reflects the distribution of herbaceous vegetation which have different structure and function under different environmental conditions.Mensurate photosynthetic day changes and light response with li-6400 in various typical sample of dominant species, and analysis photosynthetic efficiency characteristics of different plant functional groups'dominant species. The results showed that: In forest ecosystems, trees and herbs'photosynthetic characteristics are main impacted by PAR as adaptive mechanism not the same; under the same light intensity, in a short time, herbage and tree species's photosynthetic rate have little difference, the plant-light adaptation is more fargoing than people have imagined; As the impact of external conditions in forest ecosystems, plant "photosynthetic morning" phenomenon is not obvious.pH value of the forest soil,organic matter content,effective nitrogen content,available phosphorus and potassium content represents the basic content of the soil nutrient status, these factors have the closest relations with PFTs. Quantity and distribution of different PFTS (trees, shrubs, herbs) and the forest soil have certain law:pH value,organic matter content,effective nitrogen content,available phosphorus and potassium content of the southern slope are higher than that of the North Slope basically content; pH value have little changes in elevation; pH value,organic matter content,effective nitrogen content and potassium content are rising along altitude rise; Available phosphorus have high content in the low-altitude; Qrganic matter content,effective nitrogen content,available phosphorus and potassium content are lower in deep soil, pH values have little changes.The distribution of plant functional groups is closely correlated with attributes of the forest soil. Organic matter content, available nitrogen content and available potassium content all increase with elevation, while available phosphor content peaks at medium and low altitudes. Apparently nutrient content is determined by vegetation attributes, perhaps due to nutrient recycling by plants.
|
PDF Full Text Request