Algae plants are the most important primary producers on earth. The total amount of organic carbon produced by photosynthesis is about 7 times that of higher plants, and nitrogen-fixing algae (and nitrogen-fixing bacteria) can fix about 65.438+0.7 billion tons of nitrogen every year. Therefore, algae is not only an extremely important food source for humans and animals, but also the most important source of oxygen in the atmosphere. It goes without saying that they have a far-reaching impact on the material cycle and environmental quality of natural ecosystems.

Algae plants are widely distributed in the ocean and various inland waters (including lakes, reservoirs, rivers, streams, swamps, ponds, springs, ice and snow, etc.). ) and wetland surface, in which freshwater algae grow in inland freshwater bodies and saltwater algae are distributed in ocean and inland saltwater bodies. China algae include: cyanophyta in prokaryotes; Protozoa include Bacillariophyta, Dinophyta, Chrysophyta, Xanthophyta, Cryptophyta, Gymnophyta and Rhodophyta, Phaeophyta, Chlorophyta and Charophyta belonging to the plant kingdom, among which 2458 species of algae have been recorded (details will be discussed in the marine section). Only the diversity and threats of freshwater algae in China are discussed here.

1, freshwater algae diversity in China.

Due to the vast territory and complex natural environment of China, the freshwater algae resources in China are also very rich and diverse. The investigation in the past hundred years shows that all kinds of freshwater algae have been found in China, and the species are very rich. There are about 40,000 species of algae in the world, including about 25,000 species of freshwater algae, and about 9,000 species of freshwater algae have been found in China (including reported and identified but not reported). However, due to the fact that there are still many areas in China that have not been investigated for algae, even some areas that have been investigated for algae are not very comprehensive, and the investigation and study of most kinds of freshwater algae in China are still lacking in depth and breadth, the number of freshwater algae in China should far exceed 9000, and it is estimated that there are about 12000 ~ 15000 (accounting for 50% ~ 60% of the freshwater algae species in the world).

Freshwater red algae and brown algae that remain in fresh water during the evolution of land and ocean almost all grow in clean, low-temperature and relatively stable water environment, such as spring water, well water and stream water (especially spring water environment), and their distribution areas are quite narrow and have a certain degree of closure. Because they have adapted to these environments for a long time, many rare and unique species have been formed, which is of high academic value for studying the changes of the earth's environment and the evolution of organisms themselves. They are rarely distributed in fresh water all over the world. In China, after collecting and studying these algae for half a century, it is found that some species have been recorded only once. There are 65,438+02 species of this algae, including a freshwater brown algae. And freshwater red algae, such as Leuconostoc, Leuconostoc China, Porphyra China, Gracilaria lemaneiformis and Nitella var. Angusta should be listed as a rare species.

2. Threatened freshwater algae resources in China.

(1) Threatened Species Although China is rich in freshwater algae resources, some rare species have been extinct or endangered due to changes in the natural environment and human activities (especially the development of industry and cities), among which freshwater red algae and brown algae are the most seriously threatened. In recent decades, due to the climate drought or industrial development, groundwater has been over-exploited in many areas in northern China, which has led to the decline of groundwater level, making the water sources in some famous spring areas exhausted or on the verge of exhaustion. The springs in Jinan, Jinci in Shanxi and Niangziguan are famous examples. The depletion of spring water makes those endemic algae (especially freshwater red algae) that rely on spring water environment to grow face bad luck, and some have disappeared. Freshwater brown algae are even rarer. China was only found in Jialing River in Chongqing, Sichuan in the early 1940s, but it has disappeared for decades due to the evolution of the environment.

In recent 10 years, China's economy has developed rapidly and many spring water resources have been developed and utilized. However, due to people's lack of awareness of protecting the spring environment, freshwater red algae and other spring organisms growing in it are on the verge of extinction, and some even become extinct. Pearl Spring in Pukou, Nanjing was once rich in freshwater red algae: Batrachos-permum ectocarpum and Compsopogon spp. But with the development of tourist areas, the red algae there are almost extinct now. Leuconostoc deliciosa also grows in Jinci, Taiyuan, Shanxi, and some of them exist in 1994. 1995 has died out due to the exhaustion of spring water. We can imagine those springs (tourism or drinks) that are being developed. If we don't pay attention to protecting the environment in spring, algae and other spring creatures may face the same fate.

In other water bodies where large freshwater algae grow, environmental changes are often caused by human activities, leading to the disappearance of large freshwater algae, such as Yangcheng Lake in Jiangsu Province, where large charophytes die in pieces. Another example is desmids, the original main algae in Wuhan East Lake, which mainly grows in clean water. However, due to the intensification of eutrophication, it has been gradually replaced by anti-pollution algae such as cyanobacteria and Chlorella since the 1970s. Similar situations are already very common.

(2) The structure of species diversity was destroyed. Under normal circumstances, in an ecosystem (especially aquatic ecosystem), the species structure of algae community maintains a good state of diversity, that is, there are many species, but there are not many individuals in each species. At this time, the algae community plays a good ecological benefit-maintaining good water quality and abundant aquatic products. However, when the aquatic ecosystem undergoes reverse transformation-heavy metal pollution or high eutrophication, the species diversity of algae community is destroyed, and some species grow abnormally, leading to harmful red tides (in the ocean) or blooms (in fresh water), and causing pipeline blockage, water quality deterioration, endangering fishery production and even fish poisoning. With the acceleration of industrialization and urbanization, such serious environmental problems have become common occurrences. The common algae that can form harmful algal blooms in China are cyanobacteria, which are often toxic. Microcystis is the main algae, ANABAENA, ANABAENA, Tremella, Phaeocystis and so on. They occur in many places in China, which is very harmful. Prymnesium parvum is a kind of toxic dinoflagellate, and its proliferation has led to many poisoning incidents of farmed fish. Diatoms occasionally appear in a large area, among which Cyclotella meneghiniana, a diatom bloom about 200km from the Hanjiang River in Hubei Province, appears at the turn of winter and spring in 199 1. This water bloom has caused great harm and seriously affected the industrial production and residents' life in Wuhan and along the Yangtze River.

3. Protection of freshwater algae in China.

As can be seen from the above, although China's freshwater algae resources are abundant, they have been seriously threatened at present. If measures are not taken to protect them in time, many rare species may soon become extinct. In particular, at present, people's attention to biodiversity protection is mainly focused on large animals and plants, and little attention is paid to microorganisms such as algae. This situation must change. While protecting large animals and plants, we should strengthen the protection of small plants.

first

1, lichen diversity in China.

Lichen is a special kind of fungi, which can only survive in the ecosystem with algae or cyanobacteria in nature. So lichen itself is also the embodiment of the diversity of living ecosystem. There are about 20,000 known lichen species in the world, but there are less than 2,000 in China. Of these 2000 species, about 200 are endemic to China. However, there are many more lichens in the world or in China. Especially, the research on lichen species diversity in China has just started.

2. Rare and endangered lichens and their threatened status in China.

Due to air pollution and deforestation, lichen diversity in many areas of China is threatened. Species endemic to China and East Asia that depend on forest bark epiphysis, such as Trichophyton hypoconis, Trichophyton hypoconis, Trichophyton frost, Astragalus sinicus, Trichophyton transversalis and Tremella yunnanensis. Because their rise and fall are closely related to the rise and fall of forest ecosystem diversity. For example, Lasallia mayebarae is an endemic epiphytic species in China, which is of great significance in systematic evolution. However, in Lijiang, Yunnan, this rare species in the world was swallowed up by forest fires. With the large-scale development of tourism, the survival of Chinese umbilical scales, a rare lichen in the world, which grows exclusively on Huashan rocks, is also threatened. In addition, an edible lichen in East Asia, which has the potential of anti-cancer and anti-HIV, is on the verge of extinction in China Lushan and other places due to uncontrolled collection and trading. If necessary protective measures are not taken, lichens will survive, such as Dianthus longifolia and Dianthus brevifolia, Dianthus nigricans, Tannonia vermicularis and Dianthus spinosa related to anti-prostatitis drugs. Subuliformis, which can effectively lower blood pressure, is also inevitable.

3. Protection of lichens

Because human understanding of the nature of lichens has gone through a long process, lichens are still in a "virgin land" state in terms of development and utilization. Therefore, it is a treasure house of biological resources with great potential. In addition, lichens grow very slowly in nature, so it is an urgent task for us to strengthen the protection of lichens and realize sustainable utilization.

To protect the diversity of lichens, in addition to protecting the diversity of forest ecosystems on which they depend, we should also pay attention to the following protection and sustainable utilization measures:

(1) The daily chemical spices, medicinal and edible lichen resources should be mined in rotation by region and year in a planned and controlled manner.

(2) For the world's rare species with scientific significance, such as the Chinese umbilical scale in Huashan, Shaanxi, the Chinese blister umbilical coat in Lijiang, Yunnan, and the delicious tremella in Lushan, we should establish rare lichen protection communities in suitable places to protect the endemic species in China and East Asia.

(3) At the same time, some important lichens mentioned above should be cultured separately from bacteria and algae for indoor preservation. Taking a series of multi-level protection measures is an important direction of lichen species diversity protection and sustainable utilization.

(4) Strengthen the investigation, collection, separation, cultivation and research of lichen species diversity in China, and protect, study and make sustainable use of lichen diversity before it is destroyed.

Moss

1, bryophyte diversity

China is rich in bryophytes. There are 23,000 species of bryophytes in the world and 2,200 species in China, accounting for 9. 1% of the world.

The characteristics of bryophytes in China are:

(1) is rich in endemic taxa. According to the investigation results in recent decades, 35 species of endemic bryophytes are only distributed in China and East Asia (only a few are involved in neighboring areas), accounting for 7.09% of bryophytes in China. They contain 48 species, subspecies or varieties, accounting for 2.2% of the total species of bryophytes in China (table 1). These endemic genera and species have three distribution centers in Hengduan Mountain area in the southwest of China, the middle reaches of the Yangtze River basin and the southeast coastal mountainous area (Table 2).

(2) There are many groups that play a key role in the phylogeny, such as two species of the family Arachidae, the original types of the family Arachidae and the order Arachidae; Dryopteris lepidoptera and Dryopteris angustifolia are distributed in the mountains of Chayu, Bomi and Milin counties in China and Tibet.

(3) Tropical and subtropical components are dominant.

3. Bryophyte protection

Bryophytes not only have scientific value, but also have important economic value. In medicine, moss has been used as a Chinese herbal medicine for hundreds of years. In Ming Dynasty, Li Shizhen recorded Auricularia polytricha and Folium Ilicis in Compendium of Materia Medica, which have long been called "Anemone" in southwest China, and were used to treat cardiovascular diseases.

Traditionally, sphagnum or peat has been an important dressing material and horticultural fertilizer for flower seedling cultivation or transplantation, and there is no better substitute so far.

China has always been one of the major countries exporting gallnut in the world. After nearly half a century's research, Chinese scientists found that bryophytes, as overwintering hosts of gallnut aphids, are indispensable links in the production cycle of gallnut. So far, at least 20 species of bryophytes have been found to be winter host plants of gallnut aphids.

In addition, moss is a good indicator plant for monitoring environmental pollution. Moss and lichen are extremely sensitive to SO2, CO and HF in the atmosphere. In China, Cladosporium nudiflorum, humus and Cladosporium nudiflorum are common epiphytic species on tree trunks, which are sensitive to air pollution and can be used for environmental monitoring.

In a word, bryophytes are closely related to human survival, and we must attach great importance to their protection.

Sheep teeth

1. Diversity of pteridophytes in China

There are 10000 ~ 12000 species of pteridophytes in the world, and there are 2200 ~ 2600 species in China, accounting for 22% of the world's species. Due to China's vast territory and complex natural conditions, except for a few tropical families and genera, China has almost 95% of the families and genera in the world, which shows that the ferns in China are extremely diverse.

There are many important species in China, such as gymnosperms and Christensenia, the primitive groups of gymnosperms. Some genera, such as Cystoathyrium and Sinopteris, are endemic to China, and their discovery is of certain significance to the study of the evolutionary relationship of this family and genus. Adiantum lotus leaf, found along the Yangtze River in eastern Sichuan, is native to Madeira Islands in the Atlantic Ocean. The appearance of Adiantum lotus var. sinense in China provides a good material for studying the discontinuous distribution and genetic relationship of pteridophytes in China and Africa. Haloxylon glaciale is an important genus and species to study the relationship between fern morphology and ecological conditions, which can grow in the harsh environment of cold desert at an altitude of 4350m m. The fern (Struthiopteris eburnea) is an important species in typical calcareous soil, which only occurs in limestone walls in southwest China.

According to incomplete statistics, there are 500 ~ 600 species of pteridophytes endemic to China, accounting for about 25% of the known pteridophytes in China. The important endemic genera and representative species are shown in table 1.

2. Endangered ferns.

With the in-depth investigation of plants in various regions, new species of pteridophytes have been discovered continuously, but at the same time, some species have disappeared or are on the verge of extinction due to environmental changes or man-made destruction (Table 2). Except the endemic and endangered species mentioned above (table 1 and table 2). Other species are not confined to China, but only distributed in parts of China. For example, Platycerium wallichii is only produced in Yingjiang near the Myanmar border, and Marsilea aegyptica is only produced in local waters of Xinjiang. The number of individuals like these species is small and the distribution area is narrow. If they are not protected, they are easy to become extinct. There are many similar endangered species, accounting for about 30% of the total pteridophytes in China, among which 10 1 species is more important (Table 3).

There are many reasons why ferns are endangered:

(1) The destruction of forests leads to the decrease of air humidity and groundwater level, which changes the original ecological environment and affects the survival and reproduction of plant species. For example, 1984 found Pteris glabra in the forest at an altitude of 2450m in Tuanniuping, Erlang Mountain, Sichuan Province. It was found that the forest disappeared and the climate was dry, and only one plant was found in the bushes.

(2) The development of industrial and agricultural construction makes some plant species disappear in some areas, such as Isoetes sinensis and Clematis.

(3) Some ferns, such as ferns, have suffered devastating damage because they only publicize the value of some medicinal and ornamental plants without emphasizing the importance of protection, which has been difficult to see in recent years.

(4) Some small and rare plants in the tourist area, such as Hedyotis diffusa, are not protected, which leads to their being trampled and unable to grow.

3. Strengthen the protection of pteridophytes.

Pteridophytes are closely related to people's lives, many of which are traditional Chinese medicine and folk herbs, accounting for about 10% of all species. For example, Dryopteris crassirhizoma, Lygodium japonicum and Dryopteris Dryopteris can strengthen bones and tonify kidney, and Dryopteris crassirhizoma and Pyrrosia can also strengthen bones and tonify kidney. Another example is Golden Haired Dog Ridge, which has the functions of nourishing liver and kidney and strengthening waist and knees. In recent years, the export demand is great, exceeding 100 tons every year. Although this species is widely distributed, it cannot be exported indefinitely to protect it. Pteridophytes are mostly shade plants with thick leaves, which are suitable for leaf viewing plants and leaf cutting materials for flower arrangement. There are also a few kinds of leaf buds, such as fern and bracken. Can be processed into vegetables for export. Manjianghong is an excellent green fertilizer for rice, which has a structure similar to that of Nostoc commune in cyanobacteria and can fix nitrogen in the air. In a word, ferns, together with other green plants, have created the necessary environmental conditions for human survival on the earth's surface. Therefore, it is our unshirkable responsibility to strengthen the protection of pteridophytes. First of all, it is necessary to establish special reserves for some rare and endangered species that are in urgent need of protection, such as the Alsophila spinulosa nature reserve in Chishui, Guizhou. Secondly, for some special plants that can't survive in situ due to construction needs, such as the start of the Three Gorges Project on the Yangtze River, the threatened Adiantum lotus leaves need to establish experimental sites in safe places with the same or similar climate and soil environmental conditions to promote their ex situ reproduction in the wild. At the same time, it is also necessary to strengthen publicity, raise the awareness of biodiversity protection of the broad masses and cadres, and prohibit indiscriminate mining and digging of some ferns with economic value.

gymnosperm

Gymnosperms are primitive seed plants with a long history of occurrence and development. The earliest gymnosperms appeared in Paleozoic, and they were the main plants all over the continents from Mesozoic to Cenozoic. There are many kinds of gymnosperms in modern times, which appeared in the tertiary period, and then survived the ice age and have been propagated to this day. According to statistics, there are about 850 species of gymnosperms in the world, belonging to 79 genera 15 families. Although the number of species accounts for only 0.36% of angiosperms, they are distributed all over the world, especially in the cold temperate zone of the northern hemisphere and the subtropical Zhongshan-alpine zone, often forming a large area of coniferous forests.

1. Diversity of gymnosperms in China

China is a vast country with complicated climate and landform types. From Mesozoic to Cenozoic Tertiary, it has been a warm climate, and the Quaternary Ice Age was not directly damaged by the northern continental ice sheet, which basically maintained a relatively stable climate since Tertiary, resulting in the characteristics of rich species, ancient origins, many ancient remains, many endemic components and diverse types of coniferous forests in China.

According to statistics, there are about 250 species of gymnosperms 10 family, 34 genera in China, accounting for 66.6%, 4 1.5% and 29.4% of the total families, genera and species of gymnosperms in the world, respectively, making China the richest country in gymnosperms in the world. Many gymnosperms in China are ancient remnants or relict species that have long been extinct in other parts of the northern hemisphere, and they are often unique monotypic or oligotypic genera. For example, the unique haplotype family-Ginkgo biloba; The endemic monotypic genera are Metasequoia, Metasequoia, Cryptomeria, Dictyophora and Dictyophora. Semi-endemic monotypic and oligotypic genera include Taiwania, Cunninghamia lanceolata, Fokienia, Platycladus orientalis, Taxodium, Taxodium, Cycas and other remaining species. And fir.

Although gymnosperms account for only 0.8% of angiosperm species in China, the area of coniferous forest formed by them is slightly higher than that of broad-leaved forest, accounting for about 52% of the total forest area. There are few gymnosperms in coniferous forests in Northeast China, North China and Northwest China, but there are abundant gymnosperms in coniferous forests in Southwest China. In South China, Central China and East China, in addition to primary coniferous forests, large-scale artificial Chinese fir forests, Pinus massoniana forests and cypress forests are more common.

2. Threats and protection of gymnosperms in China.

Although there are abundant gymnosperms and forest resources in China, most gymnosperms have straight trunks, excellent materials and high wood yield, so the coniferous forests formed by them are often regarded as priority logging targets, which makes the resources threatened and destroyed by strong human activities. For example, in 1950s, the natural forests in Daxing 'anling, Xiaoxing 'anling and Changbai Mountain, the largest coniferous forest areas in China, were developed and utilized to varying degrees, while in 1960s and 1970s, the natural forests in Hengduan Mountain, another large coniferous forest area, were intensively cut down one after another, leaving only inaccessible mountains, deep slopes of river valleys and natural coniferous forests in nature reserves. In Central China, East China and South China, due to the demand of population density and economic development, all kinds of natural coniferous forests in Zhongshan are mostly cut down and replaced by artificial Pinus massoniana forest, Chinese fir forest and cypress forest. With the cutting and destruction of various natural coniferous forests, the original ecological environment has been changed, and the disappearance and endangerment of undergrowth creatures have been accelerated. At the same time, gymnosperms with important ornamental value and economic value have also been seriously damaged, such as Cycas Panzhihua, Cycas Guizhou, Cycas polymorpha (Cycas multiforme) and Cycas branchii (Cycas Michaelis), which have been seriously damaged after new distribution points have been published or discovered. Cephalotaxus fortunei and Taxus cuspidata were new anticancer medicinal plants discovered in 1960s, 1980s and early 1990s, and then they were destroyed by large-scale logging, resulting in a sharp decrease in resources.

China has a huge Qinghai-Tibet Plateau with an average elevation of more than 4,500 meters, as well as vast plains and lowlands, overlapping mountains, criss-crossing rivers, diverse climate and ancient geology. These are the main factors that determine the biodiversity of China, especially the richness and diversity of angiosperms. The diversity of angiosperms in China has at least the following three characteristics.

(1) The ecological types are complete. Plants with diverse life forms range from arbor, semi-arbor (such as Haloxylon ammodendron), shrub, semi-shrub (such as Calligonum Calligonum) and small semi-shrub (such as Artemisia annua) to perennial grass and annual grass. As far as ecological groups are concerned, they range from alpine tundra plants (such as Aralia octopetala and Aralia elata) to tropical rain forest species; From ultra-xerophytic desert plants to hygrophytic and aquatic species in humid lowlands; From cushion plants on the Qinghai-Tibet Plateau in the high cold wind environment to mangroves along the tropical coast of South China, all types are representative.

Each climatic zone has a large number of representative families and genera, such as betulaceae of Fagaceae and deciduous trees of Quercus, and Salicaceae, Caprifoliaceae and Berberidaceae are the representatives of temperate zones. Evergreen trees of Lauraceae, Magnoliaceae, Theaceae, Fagaceae, Hamamelidaceae, Ilex, Araliaceae, Orchidaceae, and a single species of Cercidae. As for the tropical forests in China, it is even more important for every household. The common families are Dipterocarpaceae, Annonaceae, Oliveceae, Araliaceae, Meliaceae, Garcinia, Quilicidaceae and Apiaceae.

(2) In the study of plant systematics, many primitive and ancient elements are considered as primitive or early angiosperm groups, many of which are distributed in China and some are only distributed in China. The plants of Magnoliaceae, Ranunculaceae, Hydrangeaceae, Saururaceae, Chloranthaceae, Hamamelidaceae and Akebiaceae in China are of great significance in studying the origin and phylogeny of angiosperms. In recent years, China has made great achievements in the discovery and research of angiosperm fossils, which is of great significance to reveal the species diversity of covering plants and the phylogeny of angiosperms.

(3) Abundant endemic types There are many types of angiosperms in China, among which endemic types account for a large proportion. Up to now, there are 246 genera 17000 endemic species of angiosperms in China. Ancient relict species Bole, Cercidiphyllum, Dipterocarpus, Lankun and Cabernet Sauvignon. Liriodendron chinense, Celastrus chinensis, Helianthus chinensis, Celastrus chinensis, Liriodendron chinense and Davidia involucrata are all endemic plants in China. The study of these plants is very important for understanding the historical process of angiosperm phylogeny and species diversity formation in China and even the world.

The endemic genera and species of angiosperms in China are mainly distributed in the south of Qinling-Dabie Mountain and the southeast of Hengduan Mountain, among which the endemic genera and species are relatively concentrated in three centers: (1) the center of eastern Sichuan-western Hubei-northwest Hunan, where almost all the endemic woody genera of angiosperms are deciduous trees or shrubs of temperate nature; (2) The center of western Sichuan-northwest Yunnan is the southern section of Hengduan Mountains, and herbaceous genera account for a high proportion of all genera. Almost all woody genera of angiosperms are deciduous trees or shrubs. The rapid and intense uplift of the Qinghai-Tibet Plateau has produced a large number of new endemic species in this area, which greatly enriched the diversity of angiosperms in China. (3) The center of Southeast Yunnan-West Guangxi is located near the Tropic of Cancer, and lives on the dividing line between pan-Arctic flora and paleotropical flora. Almost half of the tree cuttings are evergreen plants.

Endemic lianas are woody lianas, belonging to tropical families, showing obvious tropical characteristics.

3. Vigorously strengthen the protection of angiosperms in China.

Angiosperm is the largest of the large plants, and it is most closely related to human food, clothing, housing, transportation, medicine and industrial raw materials. The mass extinction of angiosperms will undoubtedly pose a great threat to human beings, so we must pay special attention to the protection of angiosperms. In order to protect them effectively, it is necessary to study the way, degree and extinction process of their threats, so as to formulate reasonable protection strategies. In this respect, analyzing the population viability (PVA) and determining the minimum survival population (MVP) are the core contents.

At present, there is no condition for in-depth PVA analysis of each species, and it is necessary to appropriately expand the scope of protection, otherwise a species will never recover after extinction.

At the same time, special attention should be paid to reducing the factors that cause endangered and extinct species, such as preventing forest destruction, prohibiting over-exploitation of economically valuable species, establishing as many protected areas as possible, strengthening the management of protected areas, and taking ex-situ protection measures (changing wild areas into farmland) when necessary, and so on. All these must be guaranteed by laws and policies. Only in this way can China's rich angiosperm species diversity be effectively protected, and it can make due contributions not only to the people of China, but also to the well-being of all mankind.