China is a country rich in diverse forest ecosystems due to the large span of the country, complex topography, and multiple climate regimes. In this paper, the basic information of forest resources in China was briefly introduced and the current state in the measurements of forest biodiversity and the establishment of forest biodiversity index systems in related studies were reviewed. The results showed that a lot of studies on forest biodiversity have been conducted mostly at landscape or stand level in China and the commonly used biodiversity indicators were identified and compared. Several comprehensive forest biodiversity index systems were proposed. However, there are still some problems during the construction of forest biodiversity assessment system. Due to the late establishment of biodiversity monitoring system in China, the availability of data that could be included in a forest biodiversity index system is limited, which hurdles the precise assessment of forest biodiversity. It is suggested to develop long-term monitoring stations and keep data recording consistently. Concerns should also be given to the construction of the framework of the forest biodiversity index system and the determination of the indicators’ weight. The results will provide reference for the establishment of national or regional forest biodiversity evaluation indicator systems in China.
Forest biodiversity refers to all forms of life found in forests, including plants, animals, fungi, and microorganisms, and their roles in nature. It may be the richest of all the terrestrial ecosystems. Tropical forests alone contain some 50 percent of all known vertebrates, 60 percent of plant species, and possibly 90 percent of the world’s total species [
China is one of the megadiverse countries in the world, which has more than 35,000 species of higher plants (ranking 3rd in the world) and 6,347 species of vertebrates (13.7 percent of the total in the world) [
The objectives of this paper are to briefly introduce the basic information of forest resources in China and then review the evaluation indicators and forest biodiversity index systems in related studies. The results will provide reference for the establishment of national or regional forest biodiversity evaluation indicator systems in China.
China is a country rich in diverse forest ecosystems due to the large span of the country (from south to north 5500 km and from east to west 5200 km), complex topography, and multiple climate regimes. The distribution of forests across the country is uneven. The majority of forests are distributed in the northeastern and southern parts of China and in the southeastern periphery of the Tibetan Plateau, with a few forested areas scattered in the higher mountains and along the rivers in the desert area of the western part of China [
Coniferous forests are distributed widely throughout the country. However, zonal coniferous forests occur mainly in northeast and northwest China, as well as in the subalpine areas of southwest and southeast Tibet. They include boreal coniferous and subalpine coniferous forests, warm-temperate coniferous forests, subtropical coniferous forests, and tropical coniferous forests.
The mixed forest of
Broadleaved forests include deciduous broadleaved forests, evergreen broadleaved forests, sclerophyllous forests, mixed deciduous and evergreen broadleaved forests, monsoon forests, tropical rain forests, and seasonal rain forests [
Over the past two decades, the rapid industrialization and urbanization processes placed heavy pressure on forest resources in China. Forest degradation, resource depletion, loss of biodiversity, and resilience in ecosystems become the major environmental issues. To conserve natural forests in the specified regions of China, the logging ban was imposed in 1998 to cover the natural forests in the upper reaches of the Yangtze River, the middle and upper reaches of the Yellow River, and the upper reaches of the Songhuajiang River, Sichuan, Yunnan, Chongqing, Gansu, Shaanxi, and Qinghai Provinces, which is also called the Natural Forest Conservation Program (NFCP) [
According to China’s 4th National Report to the Convention on Biological Diversity, the forest resources are continuously increasing since 1989, and China has become the fastest growing country in forest resources in the world, with an increase of 4 million hectares on average per year [
Changes of forest cover and coverage over time in China.
Biodiversity includes diversity within species, between species, and of ecosystems. Three main components of biodiversity have been widely recognized, including composition, structure, and function [
Alpha diversity indices are commonly used in the studies of forest biodiversity assessment in China compared to other indices. Alpha diversity indices can be classified into four categories: species richness index, species evenness index, species diversity index, and species dominance index. Species dominance, evenness, and diversity are closely related to each other, which reflect the composition, structure, and levels of a community. Species richness can be expressed as the number of species, Margalef richness index, Gleason richness index, or Menhinick richness index [
Alpha diversity indices have been applied in different types of forests at different geographical locations in China. For example, Hao et al. [
The commonly used beta diversity indices include Whittaker index, Cody index, Routledge index, and Wilson and Shmida index [
Since many native forests in China have been altered by management of varying intensities, it is necessary to compare biodiversity between managed and unmanaged forests in order to maintain biodiversity and sustainable forest management. Old-growth forests are well known for their high biodiversity [
In addition to the measurement of forest biodiversity, several biodiversity evaluation systems have been put forward. The Pressure-State-Response (PSR) model was developed by Anthony Friend in the 1970s, and subsequently adopted by the OECD’s State of the Environment (SOE) group. The PSR model provides a classification into indicators of environmental pressures, indicators of environmental conditions (state) and indicators of societal responses. The researchers in China combined the theory thought in PSR model and the characteristics of biodiversity in China, and established a series of evaluation index systems. For example, Yang et al. [
Besides the PSR model, other methods such as Analytical Hierarchy Process (AHP) and Delphi method were used in the establishment of forest biodiversity index system. For example, Zeng et al. [
A forest biodiversity index system was established at forestry bureau level [
Wan et al. [
Cheng [
In short, the establishment of forest biodiversity index system mainly focuses on the evaluation of forest ecosystem diversity and the variations of species diversity within the ecosystems. However, due to the limited knowledge of genetic biodiversity, the understanding on the species in the forest and forest ecosystem diversity are still insufficient, which present some difficulties in evaluating the entire forest biodiversity [
Due to the late establishment of biodiversity monitoring system in China, there exist some problems associated with data collection for biodiversity assessment and policy-making. The data used in most studies were from publications, government statistics, institute owned data, or field collection [
With regard to the study method, the selection of the measurement indices for forest biodiversity is still vague and unclear. There is a diversity of alpha diversity indices, including log alpha, log normal lambda, Q-statistic, Simpson, McIntosh, Berger-Parker, Shannon-Wiener, and Brillouin. However, how to choose these indices should be considered before applying them directly in any research. Several principles can be applied while selecting the indices, including appropriateness of each index for the data, discriminant ability of the index, statistical comparability, and widespread utility of the index [
Currently, several forest biodiversity index systems have been proposed; however, there are still some problems in determining the weights of the evaluation criteria. On one hand, researchers continuously put forward new indices in order to perfect the index system but enlarge the number of indices, which will result in the difficulties of evaluation. On the other hand, due to the lack of effective and scientific method of indicator selection, most indices were chosen based on the experience of the researchers, which make the selection prone to be subjective. In recent years, with the application of linear algebra, fuzzy mathematics, and set theory, the determination of the indices’ weight is changing from qualitative and subjective to quantitative and objective, which can help determine the weights of indices more scientifically and reasonably [
The research on the assessment of forest biodiversity is diverse and very complicated; therefore it is nearly impossible to elaborate all the aspects of this issue. In this paper, the forest ecosystems and their current status in China were briefly introduced and some related studies on evaluation system of forest biodiversity were reviewed. The results showed that a lot of studies on forest biodiversity have been conducted mostly at landscape or stand level in China and the commonly used biodiversity indicators were identified. Several comprehensive forest biodiversity index systems were proposed. However, there are still some problems associated with forest biodiversity assessment. Due to the late establishment of biodiversity monitoring system in China, the availability of data that could be included in a forest biodiversity index system are limited, which hurdles the precise assessment of forest biodiversity. It is suggested to develop long-term monitoring stations and keep data recording consistently. Concerns should also be given to the construction of the framework of the forest biodiversity index system and the determination of the indicators’ weight. The results will provide reference for the establishment of national or regional forest biodiversity evaluation indicator systems in China.
This research was financially supported by a Grant from the National Key Technology R&D Program of China during the 12th Five-Year plan period (2012BAC01B03-3). In addition, the authors would like to give thanks to the anonymous reviewers and editor for providing helpful comments to the paper.