Species Composition and Diversity Analysis of Lava Flow in Different Periods in Wudalianchi Nature Reserve, China

Huang Qing-yang , Zhu Dao-guan , Cao Hong-jie , Xie Li-hong , and Ni Hong-wei *

1 Institute of Natural Resources and Ecology, Heilongjiang Academy of Sciences, Harbin 150040, China

2 National and Provincial Joint Engineering Laboratory of Wetlands and Ecological Conservation, Harbin 150040, China

Abstract: The species composition and succession discipline after eruption of volcanoes in Wudalianchi Nature Reserve, China,including new volcanoes, such as Huoshao and Laohei Mountains, and old volcanoes, such as East Jiaodebu, Wohu and North Gelaqiu Mountains, in different historical periods were investigated by adopting the concept of space as a substitute for time. The species composition, community characteristics and diversity analysis in the remains of volcanic lava flow at various stages were analyzed. The results showed that 192 types of vascular plants that belonged to 50 families and 126 genera in the survey areas existed in the restoration process of primary succession. At the same time, the agglomeration process of plant community succession and the diversity of dominant community were investigated, and the changes in plant diversity at different succession stages were calculated using Margalef, Simpson, Shannon–Wiener, Pielou, Jaccard and Cody indices.

Key words: plant diversity, species composition, succession, volcano

Introduction

Wudalianchi Nature Reserve is an area in the region near Greater Khingan Mountains, Lesser Khingan Mountains and Songnen Plain in Heilongjiang Province; in this area, seven large-scale volcanic eruptions and 14 volcano types, which are the bestpreserved inland volcano relics in China in different periods, have been observed in the past two million years (Zhou et al., 2011). Researches on volcanoes in Wudalianchi Nature Reserve focus on geological and geomor-phological features and mineral springs(Gui et al., 2012; Xiao and Wang, 2009; Xu et al., 2013).

Several studies on volcanic vegetation have been conducted by the United States, Russia, Japan and New Zealand because of the increasing occurrence of volcanic activities abroad in modern times, such as in Krakatoa volcano in Kamchatka Peninsula,Russia in 1907 (Jones, 2003), Usu volcano in Japan in 1943 (Tsuyuzaki and Goto, 2001) and Mount St.Helens volcano in the United States in 1980 (Dale and Adams, 2003). In recent years, the distribution and characteristics of volcanic vegetation, mainly in the the vegetation community in new volcanoes, including Jingpo Lake, Changbai Mountain and Wudalianchi Nature Reserve (Hong et al., 2002; Zhang, 2005;Shen et al., 2011), attracted the interest of researchers in China. However, valuable researches on plant succession regarding volcanoes have not been reported in China.

Stages in lava bare ground, such as lichen, moss,herb, shrub and tree, are required, because the primary succession caused by volcanic eruptions is complex,due to the moisture and weathering of exposed lava.Succession to the climax community takes hundreds or even millions of years of evolutionary process in Wudalianchi Nature Reserve. This study investigated the diversity of community and the constitution of plants after the eruption of Wudalianchi volcano in different historical periods and revealed the unique evolution and ecological succession of plants after the eruption in two million years, thereby providing important scientific bases for temperate forest and unique vegetation successions.

Materials and Methods

Natural survey of plot

Wudalianchi Nature Reserve was located in Heihe City, Heilongjiang Province (elevation 248-600 m,126.00-126.25'N, 48.30'-48.50'E). The core area of Wudalianchi Nature Reserve was 517.59 km2with a buffer area of 471.07 km2; thus, the total area covered approximately 988.66 km2. The protection area had a temperate continental monsoon climate with an average temperature of -0.5℃. The average yearly precipitation was 476.33 mm, the average relative humidity over the years is 69.2%, and the annual frostfree period was 121 days. Table 1 shows the general situation of the plot.

Experimental method infield

The sampling survey on the diversity of community species in different succession stages in Wudalianchi Nature Reserve was conducted by using "space replacing time" method. Samples were set in different volcanic lava areas, and samples of tree, shrub and herb were investigated.

The survey was conducted using the pulling line method. A standard plot was set for every 20 m, three 10 m×10 m tree plots were selected, and four 2 m×2 m shrub plots andfive 1 m×1 m herb plots in each tree plot were set. The height, quantity, DBH (diameter at breast height) and canopy breadth of the tree, as well as the degree of development of the community, were recorded; the height, coverage and species of shrubs and herbs, the number of trees and habitat factors, such as altitude, aspect, slope and slope position, were also recorded, while plotted the study.

Table 1 Site conditions in different eruption periods of volcanoes in Wudalianchi Nature Reserve

Calculation method

1. Importance value of shrubs and herbs

Importance value (IV)=(relative abundance+relative height+relative coverage)/3

Importance value of trees

Importance value (IV)=(relative abundance+relative height+relative diameter at breast height)/3

Pielou evenness index (JP) J=H/lnS

Margalef richness index (Ma) dMa=(S–1)/lnN

Where, Niwas the importance value of species I in the quadrants; N was the total importance value of all the species within the quadrant; Pi=Ni/N and S was the total number of species within the quadrant (Ma,1994).

3. Index of β diversity

Jaccard comparability index: CJ=c/(a+b–c)

Cody index: β=(g(H)+l(H))/2=(a+b–2c)/2

Where, a and b were the numbers of species in the communities, c was the total number of species in two communities, g(H) was the number of species that increased along the habitat gradient H, and l(H) was the number of species that were lost along the habitat gradient H (Whittaker, 1972).

Results

Species constitution of community at different stages

A total of 192 types of vascular plants, including 50 families and 126 genera (Table 2), were discovered in the lava flow plot after the volcanic eruption. The recovery time after the eruption of Laohei Mountain and Huoshao Mountain in 1791 was short, the weathering of rocks was new, and the exposed degree of rock was heavy. Most plants belonged to mesophytes and xerophytes in the new-period volcano (Fig. 1). Most of the trees were Populus koreana, Populus davidiana and Betula platyphylla, which formed a sparse dwarf forest. Shrubs and herbs were mostly Rubus matsumuranus, Spiraea media, Dryopteris fragrans, Potentilla asperrima, Sedum aizoon and Artemisia sacrorum.

Rich plant species existed in an old-period volcano,such as North Gelaqiu mountain, and mid-period volcanoes, such as East Jiaodebu and Wohu mountains.Trees were mainly typical broad-leafed mixed forests consisting of Quercus mongolica, Tilia amurensis and Betula davurica. Undergrowth plants, which had a huge canopy density, such as Schisandra chinensis,Corylus heterophylla, Artemisia stolonifera and A. sylvatica.

Gathering progress of natural recovery succession of family, genus and species of plants

Fig. 2 showed that the number of family, genus, and species of plants in the gathering progress of natural recovery succession increasedfirst and then decreased in succession over time. The time of abscissa in Fig. 2 meant the period of vokanic eruption (years ago, the same as below).

Table 2 Plants composition of volcanic lava flow at different stages

Fig. 1 Life style of vascular plants in Huoshao and Laohei Mountains

Fig. 2 Change course of family, genus and species during natural recovery process of vegetation

Characteristics of α diversity changes at different stages

α diversity was an important indicator to describe the constitution of plants in the community. The succession progress of Wudalianchi Nature Reserve showed that the diversity, evenness and richness indices of the herb layer were higher than those of the tree layer. The tree layer was significantly higher than the shrub layer, showing that in the progress of plant succession, the change of plant diversity in the spatial structure was herb layer＞tree layer＞shrub layer.

In general, the change of plant diversity was not synchronized at different levels of community.The four α diversity indexes of the herb layer had an increasing trend, that was in succession to two million years, the diversity index would reach the maximum. The four α diversity indexes of the shrub layer would gradually decrease after reaching the maximum at 200 000 years with the increase of succession time. Although the four α diversity indexes of the tree layer was increasing at the earlier stage, the change was not significant at the latter stage (Fig. 3).

Fig. 3 Change of α diversity index during natural recovery process of vegetation

Characteristics of β diversity changes at different stages

β diversity was the rate of species replacement along environmental gradient change (Whittaker, 1972),which also reflected the differences in species composition among various communities. Table 3 showed that Jaccard (CJ) and Cody indices (βC) were used to investigate the change rules of various plant species in Wudalianchi Nature Reserve.

Table 3 Change of β diversity index during natural recovery process of vegetation

Discussion

Three methods of plant recovery succession and community dynamics

Space replacing time method had been a common approach in the research on community succession because time was irreversible. The trend and rate of recovery succession would be presumed by using several plots (Elgersma, 1998). New, middle-aged and old volcanoes, which have space homogeneity in topography and geomorphology, were selected to ensure the accuracy of the survey when plant succession was investigated. In addition, the repeat features of plots were selected in the selection of plots to ensure the objectivity and typicality of the information, thereby ensuring the reliability of "space replacing time".

Relationship between diversity and community succession of species

Relationship between the diversity and community succession of species was complex.

The common perspectives were the following:(1) The stability of the community and plant diversity had a close relationship, and the succession of community was developed toward higher species diversity and a more stable direction (Margalef, 1958). (2) In the early and middle stages of the succession, the diversity of species gradually increased and the maximum level was achieved at the middle stage; however,in the late period of the succession, that was, in the climax community stage, diversity gradually slowed down and stabilized (Zhu et al., 2006). (3) The variation of plant diversity showed a rapid increase at the early stage, and then decreased at the middle stage and stabilized to a certain level at the late stage (Wen et al., 1998).

In the study, during the plant recovery progress after the eruption of Wudalianchi Nature Reserve,the richness of community species, Simpson index,and Shannon–Wiener index all reached the highest in the middle stage of plant succession (200 000 years);the four α diversity indexes were relatively small in the early and middle stages of succession, which was the same as the second view, thereby confirming the middle interference hypothesis, which suggested that the middle stage of recovery succession had higher species diversity (Collins et al., 1995).

Characteristics of α diversity changes at different stages

During the formation of the old-period volcanic succession, the change of four α diversity indexes in the shrub and tree layers would decrease or slowdown,which provided the development space to the herb,thereby increasing the herbaceous diversity index further.

The diversity index of the shrub layer significantly decreased in the succession process, that was, in 1 000 000 to 2 000 000 years, when the tree layer in the old-period volcano was formed and the trees were mainly typical broad-leafed mixed forests consisting of Quercus mongolica and Betula davurica. Species of the shrub layer could not adapt to habitat changes and werefinally eliminated as the forest stand density increases, thereby decreasing the quantity of species.In the formation of the climax community, the tree layer entered into a more stable state because of being forced by the competition for sunlight and space.

Characteristics of β diversity changes at different stages

Jaccard index re flected the similarity of species composition among the communities, that was, when the Jaccard index was high, species in different communities and differences in the environmental gradient were also high (Jaccard, 1990). Jaccard index could reach the maximum of 0.6517 in 200 000 years (East Jiaodebu Mountain) and one million years after the eruption (Wohu Mountain),indicating that both species had the largest quantities and the plant community environment was similar. At 290 (Huoshao Mountain) and one million years after the eruption (Wohu Mountain), the total number of species was relatively low. The Jaccard index was only 0.0891 (Table 3).

The Cody index re flected the rate of species replacement along environmental gradient changes in the constitution of species in the community (Magurran,1988). The Cody index (species replacement rate)was 71.5, which was the maximum Cody value at 290 years (Huoshao Mountain) and 200 000 years after the volcanic eruption (East Jiaodebu Mountain).This result indicated that the evolution rate of the plant species was high and the richness of species increased, which was also consistent with the trend of Margalef richness index. The species replacement rate (Cody index) slowed down gradually 200 000(East Jiaodebu Mountain) to two million years(North Gelaqiu Mountain) after the volcanic eruption because of the recovery of the succession of volcanic eruption.

Defined of lava flow in volcano

Fourteen volcanoes in Wudalianchi Nature Reserve had seven eruption cycles and had erupted several times, thereby forming a lava relic in different periods.Records andfield researches suggested that the lava flow relic in this study was a late-period lava flow(Hou, 2005). The growth of plants in this period was totally natural, that was, plants grew under primary conditions not affected by the lava of erupted volcanoes. The research discussed the diversity change of the plant community in Wudalianchi Nature Reserve relics in different historical periods from the perspective of lava flow. The diversity change was significant,and further research should be conducted to obtain a complete understanding of the plants in Wudalianchi Nature Reserve.

Conclusions

A total of 192 species of vascular plants from 50 families and 126 genera were recorded during volcanic eruptions. The number of family, genus and species of plants in the gathering progress of natural recovery succession increasedfirst and then decreased successively over time. The change of diversity in various layers was asynchronous. Diversity indices were increased in the herb layer. However, in the tree and herb layers, the diversity index increasedfirst and then decreased or no clear trend was observed. Jaccard and Cody indices suggested that species in Huoshao and East Jiaodebu Mountains were few, and differences in the environment were large. However, the species replacement rate was high and the species richness was significant.

Acknowledgments

We are grateful to Li Hong-guang and all the researchers at the Wudalianchi Nature Reserve for their dedication to the work.