| 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 field 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 groups 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 groups of a forest ecosystem according to dominant species, therefore, is a viable approach 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. Its ecosystem 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, 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. PFGs 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 PFGs. PFG1: Q. variabilis, Q. aliena, Aldizzia kalkora, Castanea seguinii (under 1000m); PFG2: Q. glandulifera, Platycarya strobilacea, Pistacia chinensis (1100m-1400m); PFG3: Q. acutidentata, Carpinus cordata, Toxicodendron vernicifluum (1400-1800m); PFG4: P. armandi, P. tabulaeformis, Abelia biflora, Betula platyphylla, B. albo-sinensis (above 1800m). By analyzing dynamics of these plant functional groups along the moisture and temperature gradients, we have discovered that while these PFGs have similarities in several important morphological characteristics, they differ in many other vital morphological traits such as leaf size and cork thickness. Some evolutionary connections and differentiations also appear to exist among these PFGs. Highly responsive to changes in environmental conditions, herbaceous plants are very useful to the study of vegetation-environment dynamics. Following the investigation protocol applied to the tree species, seven PFGs of herbaceous plants were identified: I. anthropophilic, II. montane, III. sciophilic, IV. drought-tolerant, V. forest gap,â…¥. foundational, and VII. primordial.The dominant species showed clumped distribution patterns. Species that scored high on importance value and niche width had relatively high levels of niche overlap with other species. Species that scored low on importance value and niche width had relatively low levels of niche overlap with other species. There were however a few exceptions to these general observations.Daily photosynthetic changes and light responses of the dominant species were measured using the Li-6400 system. Photosynthetic efficiency characteristics of these species were analyzed. The results showed that the photosynthetic characteristics were mainly influenced by PAR, the plant species were adapted to light intensity ranges that were greater than expected, and there was no obvious midday depression of photosynthesis.Soil fertility is determined primarily by pH value and fractions of organic matter, available nitrogen, phosphorus and potassium. In this study, the distribution of plant functional groups appeared to be closely correlated with attributes of the forest soil. Organic matter content, available nitrogen content and available potassium content all increased with elevation, while available phosphor content peaked at medium and low altitudes. Apparently nutrient content was determined by vegetation attributes, perhaps due to nutrient recycling by plants. |
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