Shuguang Jian

Wild Plant Species with Extremely Small Populations Require Conservation and Reintroduction in China

For reintroduction of rare and endangered plants, plants protected and propagated via ex situ conservation are returned to their original natural and semi-natural ecosystems or to suitable wild habitats. The goal is to establish a population with sufficient numbers and genetic resources to enable it to adapt to change and to be self-sustaining and self-renewing (Griffith et al. 1989; IUCN 1998). International organizations have also published guidelines for the reintroduction of wild species, and at least 249 reintroduction trials involving 172 taxa have been conducted worldwide (Godefroid et al. 2011). More than 890 papers related to reintroduction have been published (Polak and Saltz 2011). To date, there have been 62 successful reintroduction cases in the world (Albrecht et al. 2011). Based on ex situ conservation and research on threatened plants, China has performed several reintroduction experiments. Until now, 38 plant species have been successfully reintroduced. Reintroduced herbs include Primulina tabacum, Paphiopedilum wardii, Paphiopedilum armeniacum, Paraisometrum mileense, Tigridiopalma magnifica, Metabriggsia ovalifolia, Paphiopedilum malipoense, and Doritis pulcherrima. Reintroduced shrubs include Myricaria laxiflora (Chen et al. 2005), Loropetalum subcordatum, and Cycas debaoensis (Ren et al. 2008). Reintroduced trees include Disanthus cercidifolius subdp longipes, Nageia nagi, Manglietia longipedunculata, Bretschneidara sinensis, Parakmeria lotungensis, Davidia involucrate, Dipteronia sinensis, Lirianthe odoratissima, Manglietia aromatica, Euryodendron excelsum, Formanodendron doichangensis, Pachylarnax sinica, Cyclobalanopsis sichourensis, Nyssa yunnanensis, and Diploknema yunnanensis (Sun et al. 2006; Zheng and Sun 2009). The lower plant Adiantum reniforme. var. sinense has also been successfully reintroduced (Ren 2012). The reintroduction of plant species with extremely small populations in China involves a number of main features and problems. Botanical gardens play an important role in the early stage of wild plant reintroduction because such gardens research introduction techniques are related to ex situ conservation. The government is important because it promotes interactions with international organizations and it develops and implements the relevant laws and regulations. For example, the State Forestry Administration approved the “Implementation Plan for Saving Wild Plants of Extremely Small Populations” in 2012; Botanical Garden Conservation International launched a “10 species program” in China aiming at insuring species survival and population recovery. Those works are conducted mainly in relatively developed areas, such as Guangdong and Zhejiang provinces, or biodiversity-rich regions (such as Yunnan province), and over a short period of time, but few related papers have been published. The plant species that have been systematically studied include Primulina tabacum, Tigridiopalma magnifica, Bretschneidara sinensis, Pachylarnax sinica, and Cyclobalanopsis sichourensis. The species that have been reintroduced are confined to those in single-species families and genera, and relic species or rare and endangered species. With respect to the reintroduction of wild plants, researchers in China have studied the ecological characteristics, population genetics, and breeding biology of 28 species. The research has confirmed that these species have narrow distribution areas and shrinking population sizes related to anthropogenic disturbance and climate change. Primulina tabacum, Tigridiopalma magnifica, and Cycas changjiangensis have had 3, 1, and 2 wild distribution points (populations), respectively, that became extinct in the past decade (Ren et al. 2010, 2012). The genetic diversity of these plants is generally low. These plants have varying degrees of natural reproduction barriers (Jian et al. 2010). To increase the successful reintroduction of rare and endangered species, researchers have combined methods of biotechnology and ecological restoration. Our investigations showed that reintroduction of Primulina tabacum often required the use of bryophytes as nurse plants (Ren et al. 2010). Successful reintroduction of Tigridiopalma magnifica indicated that rare and endangered species can be transplanted and established with anthropogenic assistance under the conditions of global climate change, which clarified current academic debate (Ren et al. 2012). We have also successfully reintroduced some trees (including species of Magnoliaceae) and produced substantial numbers of plants from seeds. Some of these seedlings have been used for urban landscaping. Most importantly, we have established the following protocol for the reintroduction of rare and endangered plants: first, select the appropriate target plant species; second, conduct basic research on their breeding and other aspects of their biology and ecology; and then, reintroduce them to the wild while also developing their market-oriented production. By consulting with regional and national agencies concerned with ecological planning, we have promoted this protocol for the reintroduction of rare and endangered plants throughout China.

Mangrove succession enriches the sediment microbial community in South China.

Sediment microorganisms help create and maintain mangrove ecosystems. Although the changes in vegetation during mangrove forest succession have been well studied, the changes in the sediment microbial community during mangrove succession are poorly understood. To investigate the changes in the sediment microbial community during succession of mangroves at Zhanjiang, South China, we used phospholipid fatty acid (PLFA) analysis and the following chronosequence from primary to climax community: unvegetated shoal; Avicennia marina community; Aegiceras corniculatum community; and Bruguiera gymnorrhiza + Rhizophora stylosa community. The PLFA concentrations of all sediment microbial groups (total microorganisms, fungi, gram-positive bacteria, gram-negative bacteria, and actinomycetes) increased significantly with each stage of mangrove succession. Microbial PLFA concentrations in the sediment were significantly lower in the wet season than in the dry season. Regression and ordination analyses indicated that the changes in the microbial community with mangrove succession were mainly associated with properties of the aboveground vegetation (mainly plant height) and the sediment (mainly sediment organic matter and total nitrogen). The changes in the sediment microbial community can probably be explained by increases in nutrients and microhabitat heterogeneity during mangrove succession.

Changes in the Macrobenthic Faunal Community during Succession of a Mangrove Forest at Zhanjiang, South China

ABSTRACT Chen, Q.; Li, J.; Zhang, L.; Lu, H.; Ren, H., and Jian, S., 2015. Changes in the macrobenthic faunal community during succession of a mangrove forest at Zhanjiang, South China. A chronosequence was used to study the community structure of the macrobenthic faunal community during succession of the mangrove forest at Zhanjiang, South China. The four successional stages studied were (from primary to late) unvegetated shoal, the Avicennia marina community, the Aegiceras corniculatum community, and the Bruguiera gymnorrhiza + Rhizophora stylosa community. Faunal density, the diversity index, species richness, and evenness index were highest in the unvegetated shoal (189 individuals/m2, 1.97, 3.48, and 0.74, respectively, in the wet season; 105 individuals/m2, 1.77, 2.20, and 0.84, respectively, in the dry season) and lowest in the B. gymnorrhiza + R. stylosa community (35 individuals/m2, 1.04, 1.10, and 0.57, respectively, in the wet season; 46 individuals/m2, 0.86, 1.16, and 0.66, respectively, in the dry season). The values for these community parameters decreased with succession. Hierarchical clustering indicated that the distribution of the macrobenthic fauna closely corresponded with the successional stages. Correlation analysis and canonical redundancy analysis (RDA) indicated that the changes in the macrobenthic fauna with mangrove succession were associated with the aboveground vegetation (mainly crown breadth and tree height) and soil physicochemical properties (mainly soil organic matter and total nitrogen content). Several species of macrobenthic fauna were only detected in certain stages of succession, suggesting that they may be biological indicators of succession.

Distribution, status, and conservation of Camellia changii Ye (Theaceae), a Critically Endangered plant endemic to southern China

The distribution of the endemic threatened plant Camellia changii Ye (Family Theaceae) is restricted to a small area in southern China, and little else is known about its status in the wild. To provide information for the conservation of C. changii we investigated its distribution, population size and structure, and habitat, and assessed its conservation status. Surveys confirmed that the species grows in a narrow band along both sides of a 4 km long segment of a stream in Ehuangzhang Nature Reserve, under the discontinuous canopy of a secondary evergreen broadleaved forest on well-drained, acidic sandy loam soil. We found a total of 1,039 individuals of C. changii . The population has a high flowering rate but a low seed-setting rate. The population appears to be in decline because no seedlings and few young plants were evident. Our findings indicate that C. changii should be categorized as Critically Endangered on the IUCN Red List. We have recommended an integrated species-conservation plan for the species that includes patrolling the Ehuangzhang Nature Reserve to prevent plant removal, establishing an ex situ living collection that contains the entire wild genetic diversity (accomplished by grafting of short cuttings from all wild individuals), facilitating propagation for commercial use, and implementing reintroduction to augment the wild population.

Isolation and characterization of microsatellite loci in endangered Cycas changjiangensis (Cycadaceae).

Eight microsatellite loci were isolated from repetitive DNA enriched libraries for Cycas changjiangensis, an endangered endemic species in Hainan Island, China. The number of allele ranged from three to seven. The observed (HO) and expected (HE) heterozygosities ranged from 0.0000 to 0.8750 and from 0.2359 to 0.7582, respectively. These microsatellite loci will enrich our scientific understanding for C. changjiangensis conservation.

Spatial and Temporal Patterns of Carbon Storage in Forest Ecosystems on Hainan Island, Southern China

Spatial and temporal patterns of carbon (C) storage in forest ecosystems significantly affect the terrestrial C budget, but such patterns are unclear in the forests in Hainan Province, the largest tropical island in China. Here, we estimated the spatial and temporal patterns of C storage from 1993–2008 in Hainans forest ecosystems by combining our measured data with four consecutive national forest inventories data. Forest coverage increased from 20.7% in the 1950s to 56.4% in the 2010s. The average C density of 163.7 Mg C/ha in Hainans forest ecosystems in this study was slightly higher than that of Chinas mainland forests, but was remarkably lower than that in the tropical forests worldwide. Total forest ecosystem C storage in Hainan increased from 109.51 Tg in 1993 to 279.17 Tg in 2008. Soil C accounted for more than 70% of total forest ecosystem C. The spatial distribution of forest C storage in Hainan was uneven, reflecting differences in land use change and forest management. The potential carbon sequestration of forest ecosystems was 77.3 Tg C if all forested lands were restored to natural tropical forests. To increase the C sequestration potential on Hainan Island, future forest management should focus on the conservation of natural forests, selection of tree species, planting of understory species, and implementation of sustainable practices.

Genetic variation in Heritiera littoralis (Malvaceae) from east and south Asia revealed by AFLP markers

Abstract Heritiera littoralis Dryand (Malvaceae) is a mangrove tree that can grow in both intertidal wetland and inland habitats. Due to natural and human impacts, populations of this species have been fragmented. We used amplified fragment length polymorphism markers to determine the genetic variations in 13 natural populations of H. littoralis from China, Japan, and Thailand. Our results revealed a relatively high level of genetic variation (at population level: P = 35.71%, H = 0.127, and I = 0.190; at species level: P = 77.47%, H = 0.221, and I = 0.342) and a high level of genetic differentiation among populations (G ST = 0.336) in this species. The results also suggest that the origins of the current populations of H. littoralis in Asia lie in two gene pools. These findings imply that as many populations as possible should be preserved in situ for the conservation of this species. Given their genetic variability and origin, the Thai populations should be assigned priority for conservation.

Genetic diversity and population structure in Elephantopus scaber (Asteraceae) from South China as revealed by ISSR markers

Abstract We used inter-simple sequence repeat (ISSR) markers to investigate genetic variation in eight natural populations of Elephantopus scaber from South China, including Guangdong, Hainan and Hong Kong. Eleven primers produced 247 bands across all 184 individuals, of which 243 (98.4%) were polymorphic. The average genetic diversity at the species and population levels was estimated to be 0.283 and 0.103, respectively, using mean expected heterozygosity. The average gene differentiation (F ST) among populations was 0.725. AMOVA analysis showed that the partition of molecular variation between and within populations was 72.5% and 27.5%, respectively. The effective number of migrants among populations based on the F ST was relatively low (N m = 0.095). Cluster analysis based on Neis genetic distance and the neighbour-joining method revealed the genetic relationships among the populations of E. scaber. The Mantel test indicated that there was no significant correlation between population genetic and geographic distances. The results obtained from the AMOVA analysis, the cluster analysis, and the Mantel test all suggested that fragmented local environments and human disturbance might play important roles in shaping the population structure of E. scaber.

Development of microsatellite markers for Suriana maritima (Surianaceae) using next-generation sequencing technology.

Our objective was to develop microsatellite markers for use in assessing genetic variation in the small shrub or tree species Suriana maritima (Surianaceae). In China, this species is found only as a few fragmented populations and individuals on the Paracel Islands. Using next-generation genome sequencing methodology, we developed 17 novel microsatellite markers for S. maritima. Fifty-four individuals from six populations of S. maritima were examined for polymorphisms; only one allele was detected for each of the markers. Microsatellite loci developed indicate a complete absence of genetic diversity for S. maritima on the Paracel Islands in China. These markers will be useful for examining genetic variation among S. maritima populations in other areas of the world.

Development and Application of Transcriptome-Derived Microsatellites in Actinidia eriantha (Actinidiaceae)

Actinidia eriantha Benth. is a diploid perennial woody vine native to China and is recognized as a valuable species for commercial kiwifruit improvement with high levels of ascorbic acid as well as having been used in traditional Chinese medicine. Due to the lack of genomic resources for the species, microsatellite markers for population genetics studies are scarce. In this study, RNASeq was conducted on fruit tissue of A. eriantha, yielding 5,678,129 reads with a total output of 3.41 Gb. De novo assembly yielded 69,783 non-redundant unigenes (41.3 Mb), of which 21,730 were annotated using protein databases. A total of 8,658 EST-SSR loci were identified in 7,495 unigene sequences, for which primer pairs were successfully designed for 3,842 loci (44.4%). Among these, 183 primer pairs were assayed for PCR amplification, yielding 69 with detectable polymorphism in A. eriantha. Additionally, 61 of the 69 polymorphic loci could be successfully amplified in at least one other Actinidia species. Of these, 14 polymorphic loci (mean NA = 6.07 ± 2.30) were randomly selected for assessing levels of genetic diversity and population structure within A. eriantha. Finally, a neighbor-joining tree and Bayesian clustering analysis showed distinct clustering into two groups (K = 2), agreeing with the geographical distributions of these populations. Overall, our results will facilitate further studies of genetic diversity within A. eriantha and will aid in discriminating outlier loci involved in local adaptation.