Annual Litter Research Articles

森林群落物种组成对凋落物组成的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 森林群落物种组成对凋落物组成的影响 DOI: 10.5846/stxb201404160742 作者: 作者单位: 海南大学热带作物种质资源保护与开发利用教育部重点实验室,海南大学热带作物种质资源保护与开发利用教育部重点实验室,海南大学热带作物种质资源保护与开发利用教育部重点实验室,海南大学热带作物种质资源保护与开发利用教育部重点实验室,海南大学热带作物种质资源保护与开发利用教育部重点实验室,海南大学热带作物种质资源保护与开发利用教育部重点实验室,海南大学热带作物种质资源保护与开发利用教育部重点实验室 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金(31460120);国家科技支撑计划(2012BAC18B04-3-1);海南大学中西部提升计划项目(研究生联合培养基地建设) Impact of forest community species composition on litter species composition Author: Affiliation: Key Laboratory of Protection and Development Utilization of Tropical Crop GermplasmResources,Hainan University,Minristry of Education,Key Laboratory of Protection and Development Utilization of Tropical Crop GermplasmResources,Hainan University,Minristry of Education,Key Laboratory of Protection and Development Utilization of Tropical Crop GermplasmResources,Hainan University,Minristry of Education,Key Laboratory of Protection and Development Utilization of Tropical Crop GermplasmResources,Hainan University,Minristry of Education,Key Laboratory of Protection and Development Utilization of Tropical Crop GermplasmResources,Hainan University,Minristry of Education,Key Laboratory of Protection and Development Utilization of Tropical Crop GermplasmResources,Hainan University,Minristry of Education,Key Laboratory of Protection and Development Utilization of Tropical Crop GermplasmResources,Hainan University,Minristry of Education Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:在海南铜鼓岭山麓灌木林和季雨矮林固定大样地的基础上,通过收集凋落物,比较两林型的凋落物数量及其器官组成、凋落叶物种组成,探讨森林群落物种组成与凋落物组成的关系.结果表明:(1)两林型的凋落物总量及其器官组成不同,山麓灌木林(6.227 t/hm2)比季雨矮林的年凋落量大(5.636 t/hm2);凋落叶是凋落物的主要组成部分,能反映凋落物的凋落情况.(2)山麓灌木林凋落物优势种和主要物种为贡甲、林仔竹、橄树等15个物种,凋落叶总量占77.72%;季雨矮林的凋落物优势种和主要物种为方枝蒲桃、肖蒲桃、贡甲等17个物种,凋落叶总量占71.84%;山麓灌木林中凋落物优势种和主要物种的叶凋落量与其组成物种的株数、总断面积、树冠面积极显著正相关,而季雨矮林的凋落物优势种和主要物种的叶凋落量与其组成物种的株数极显著正相关.山麓灌木林中两者的Jaccard 相似性系数为20%,季雨矮林为25.93%,两林型的群落物种组成与凋落叶物种组成不一致,热带森林群落优势种不一定是凋落物优势种. Abstract:Based on fixed sample plot data form the shrub and monsoon elfin forests in Tongguling on Hainan Island, we selected two permanent plots and set up litter traps to compare litter production, its organ composition, and leaf litter species compositions between the two forest types, as well as to assess the relationships between forest community and litter species composition. The results were as follows: (1) Some differences were noted between the two forest types in total litter and its organ composition. The annual litter amount obtained from shrub forest(6.227 t/hm2) was larger than that from monsoon elfin forests (5.636 t/hm2). Leaf litter was the main component of the litter in both the shrub and monsoon elfin forests, and it is reflective of the litter condition. (2) In the shrub forest, 15 dominant and main leaf litter species were noted, including Acronychia oligophlebia, Oligostachyum nuspiculum, and Aporosa yunnanensis; the leaf litter amount of these species accounted for 77.72% of the total litter. In the monsoon elfin forests, 17 dominant and main leaf litter species were noted, including Syzygium tephrodes, S.acuminatissima, and A.oligophlebia; these species accounted for 71.84% of the total litter. Thus, we showed that the dominant and main species of leaf litter greatly contribute to the total leaf litter in both forests. Relativity analysis of the leaf litter amount and stand characteristic indexes of the dominant and main species in the shrub forest showed significantly positive correlations between the leaf litter amount of both species and their individual numbers, total basal areas, and crown areas. However, in monsoon elfin forests, the leaf litter amount of the dominant and main species showed significant positive correlations with the number of individuals of the tree species. A comparison between community species composition and leaf litter composition showed that, in the shrub forest, the Jaccard similarity coefficient was 20%, while that in the monsoon elfin forests was 25.93%. The similarity coefficients of the two forest types were not high, suggesting that the species composition was not consistent between the community and leaf litter in either forest type. In other words, community species composition has little influence on the leaf litter species composition, showing that the dominant forest species may not be the same as the dominant litter species. 参考文献 相似文献 引证文献

Influence of Soil Moisture on Litter Respiration in the Semiarid Loess Plateau

Understanding the response mechanisms of litter respiration to soil moisture in water-limited semi-arid regions is of vital importance to better understanding the interplay between ecological processes and the local carbon cycle. In situ soil respiration was monitored during 2010–2012 under various conditions (normal litter, no litter, and double litter treatments) in a 30-year-old artificial black locust plantation (Robinia pseudoacacia L.) on the Loess Plateau. Litter respiration with normal and double litter treatments exhibited similar seasonal variation, with the maximum value obtained in summer (0.57 and 1.51 μmol m−2 s−1 under normal and double litter conditions, respectively) and the minimum in spring (0.27 and 0.69 μmol m−2 s−1 under normal and double litter conditions, respectively). On average, annual cumulative litter respiration was 115 and 300 g C m−2 y−1 under normal and double litter conditions, respectively. Using a soil temperature of 17°C as the critical point, the relationship between litter respiration and soil moisture was found to follow quadratic functions well, whereas the determination coefficient was much greater at high soil temperature than at low soil temperature (33–35% vs. 22–24%). Litter respiration was significantly higher in 2010 and 2012 than in 2011 under both normal litter (132–165 g C m−2 y−1 vs. 48 g C m−2 y−1) and double litter (389–418 g C m−2 y−1 vs. 93 g C m−2 y−1) conditions. Such significant interannual variations were largely ascribed to the differences in summer rainfall. Our study demonstrates that, apart from soil temperature, moisture also has significant influence on litter respiration in semi-arid regions.

Aboveground Forest Biomass and Litter Production Patterns in Atlantic White Cedar Swamps of Differing Hydroperiods

Ecosystems dominated by Chamaecyparis thyoides (Atlantic White Cedar) are critically endangered due to hydrologic alterations associated with ditching, logging, development, and agricultural conversion. Few studies have related structural and functional characteristics of this plant community to water tables, yet hydrologic management options may be critical to establish a peat-based seed refugium and allow Atlantic White Cedar self-maintenance in this ecosystem. In this study, we assessed aboveground forest biomass, litter production, and depth to water table at a mature (60–70 y) and an intermediate (20–35 y) age-class stand in two national wildlife refuges, Alligator River (AR) and Great Dismal Swamp (DS) in North Carolina. We calculated forest biomass from morphometric data gathered within randomized study plots. We made monthly litter collections at each study plot from November 1998 to April 2000; litter was sorted by species and type for the first 12 months. Wells installed at each study plot recorded water-table levels, which were at or near the surface at AR but >30 cm below the soil surface at DS throughout the study. Although Atlantic White Cedar was a dominant species at all sites, community structure differed between refuges. Total aboveground biomass was similar among age classes; however, Atlantic White Cedar stem density was greater and mean diameter at breast height was lower at AR. Mean annual litter production was higher at AR sites for each age class despite a persistently high water table. We conclude that the rates of primary production associated with high water tables at AR represent favorable conditions for Atlantic White Cedar self-maintenance.

Litter Production, Decomposition, and Nutrient Release in Subalpine Forest Communities of the Northwest Himalaya

Production, decomposition, and release of nutrients from leaf and nonleaf litter were investigated in four subalpine forests of North-West Himalaya, India. Total annual litter fall in four communities varied from 2950.00 to 4040.00 kg ha−1and was found significant (CD0.05= 118.2). Decomposition of leaf litter varied from 1.82–3.5% during autumn-winter to 36.14–45.51 during summer rainy season in all stands and percent of mass loss was significantly varied in stands (CD6.00). Similarly, decomposition in nonleaf litter was varied from 0.3–1.1% during autumn-winter to 19.59–30.05% during summer rainy season and was significantly varied irrespective of seasons. However, percent decomposition of leaf litter and the values of decay constant (k) were at par in all stands. Total standing state of nutrients in fresh litter as well as release of total nitrogen (N), phosphorus (P), and potassium (K) in due course of decomposition (12 months) was also varying significantly. The rate of nonleaf litter decomposition was significantly positively correlated with air temperature (r=0.63–0.74in all communities). The significant correlation(r=0.85)was observed only inRhododendron-Sorbusforest community (PRS). Study indicates that the air temperature is a major determinant for nonleaf litter decomposition in this region.

Litter production, decomposition and nutrient mineralization dynamics of Ochlandra setigera: A rare bamboo species of Nilgiri Biosphere Reserve, India

Litter production, decomposition and nutrient release dynamics of Ochlandra setigera, a rare endemic bamboo species of Nilgiri biosphere were studied during 2011–2012 using the standard litter bag technique. Annual litter production was 1.981 t·ha−1 and was continuous throughout the year with monthly variations. Litterfall followed a triphasic pattern with two major peaks in November, 2011 and January, 2012 and a minor peak in July, 2011. The rate of decomposition in O. setigera was a good fit to the exponential decay model of Olson (1963). Litter quality and climatic conditions of the study site (maximum temperature, monthly rainfall and relative humidity) influenced the rate of decomposition. Nutrient release from the decomposing litter mass was in rank order N = Mg > K = Ca > P. Nutrient release from litter was continuous and it was in synchrony with growth of new culms. Study of litter dynamics is needed before introduction of a bamboo species into degraded or marginal lands or Agroforestry systems.

Comparing Throughfall and Litterfall Nutrient Fluxes in a Rubber (Hevea brasiliensis willd. muell-arg) Plantation Agro-ecosystem at Ikenne, South-west Nigeria

This study compares nutrient fluxes (throughfall and litterfall) in a rubber (Hevea brasiliensisWilld. Muell-Arg) plantation agro-ecosystem at Ikenne, SW Nigeria. Throughfallsamples were collected bi-weekly under the rubber canopies (40-, 15-, and 5-year-old) using throughfall funnel collectors with 10 replicates. Litterfall was collected on a monthly basis in the three rubber stands using twenty-four 0.25 m2litter traps (eight replicates in each of the three rubber stands) positioned randomly to estimate total annual litter production (dry biomass)and its main fractions. Throughfall and litterfall samples were analyzed for total nitrogen, sodium, phosphorus, calcium, potassium and magnesium. The annual means of throughfall in the different stands were compared by solution type using one-way analysis of variance (ANOVA), followed by a post-hoc separation of means by the Scheffe-test (p<0.05).The litterfall data were analyzed using one-way analysis of variance based on the representative of 12 months. The results revealed a clear pattern of increased levels of base cations and fluxesof throughfall compared to those occurring in precipitation. Fluxes of Ca2+in throughfallare typically 1.5-2 times greater than those occurring in rainfall. Among the rubber stands, fluxes of K+are also greater in throughfall, consistent with previous studies. The enrichment of elements in throughfallhas been ascribed to the dissolution andwashout of atmospheric materials deposited on the canopy.Comparison of total annual litterfall nutrient budgets show that the 15-year-old rubber stand was cycling more Mg2+, N, Na+, K+, P, and Ca2+in litterfall than the 40-and 5-year-old rubber stands.

Long-term differences in annual litter production between alien (Sonneratia apetala) and native (Kandelia obovata) mangrove species in Futian, Shenzhen, China

Annual litter production in alien (Sonneratia apetala) and native (Kandelia obovata) mangrove forests in Shenzhen, China were compared from 1999 to 2010. S. apetala had significantly higher litter production than K. obovata, with mean annual total litter of 18.1tha−1yr−1 and 15.2tha−1yr−1, respectively. The higher litter production in S. apetala forest indicates higher productivity and consequently more nutrient supply to the estuarine ecosystems but may be more invasive due to positive plant-soil feedbacks and nutrient availability to this alien species. Two peaks were recorded in S. apetala (May and October), while only one peak was observed in K. obovata, in early spring (March and April). Leaf and reproductive materials were the main contributors to litter production (>80%) in both forests. These results suggest that the ecological function of S. apetala and its invasive potential can be better understood based on a long-term litter fall analysis.

Spatial Variability in Litterfall, Litter Standing Crop and Litter Quality in a Tropical Rain Forest Region

AbstractUnderstanding the spatial variability in plant litter processes is essential for accurate comprehension of biogeochemical cycles and ecosystem function. We assessed spatial patterns in litter processes from local to regional scales, at sites throughout the wet tropical rain forests of northern Australia. We aimed to determine the controls (e.g., climate, soil, plant community composition) on annual litter standing crop, annual litterfall rate and in situ leaf litter decomposability. The level of spatial variance in these components, and leaf litter N, P, Ca, lignin, α‐cellulose and total phenolics, was determined from within the scale of subregion, to site (1 km transects) to local/plot (~30 m2). Overall, standing crop was modeled with litterfall and its chemical composition, in situ decomposability, soil Na, and topography (r2 = 0.69, 36 plots). Litterfall was most closely aligned with plant species richness and stem density (negative correlation); leaf decomposability with leaf‐P and lignin, soil Na, and dry season moisture (r2 = 0.89, 40 plots). The predominant scale of variability in litterfall rates was local (plot), while litter standing crop and α‐cellulose variability was more evenly distributed across spatial scales. Litter decomposability, N, P and phenolics were more aligned with subregional differences. Leaf litter C, lignin and Ca varied most at the site level, suggesting more local controls. We show that variability in litter quality and decomposability are more easily accounted for spatially than litterfall rates, which vary widely over short distances possibly in response to idiosyncratic patterns of disturbance.

Effect of Altitude and Age of Chir Pine Stands on Litter Production in Mid Hills of Himachal Pradesh

The litterfall under different aged (sapling, pole and mature) Chir pine stands were studied at two sites viz. Nauni and Moti Kona (Kasauli) having altitudes 1250-1275m and 1720-1745m amsl., respectively in the mid hills of Himachal Pradesh throughout the year. The litter comprised of needles, twigs / branch and bark under sapling and pole stands of Chir pine whereas cones were also the part of the total litter production under mature stands at both sites. The litterfall was maximum under mature stands followed by pole and sapling stands at Site-I whereas it was maximum under pole stand followed by mature and sapling stands at Site-II. The needles had the maximum share (93 to 99%) in the total litter under all the Chir pine stands. The average annual litter production under sapling,pole and mature stands was 64.68, 73.49 and 102.01 q/ha, respectively at Site-I whereas at Site-II, it was 33.34, 55.20 and 37.84 q/ha, respectively. The needle fall was maximum in summer months i.e. April and May under all the Chir pine stands at both the sites and it was about 60 to 70 per cent of the total litterfall of the year. The information generated from the present study may be beneficial for devising management strategies for Chir pine needle litter and can also help in making the strategies for fire control in Chir pine forests of mid hills of Himalayas.

English

The present paper reports on the leaf litter, wood litter, miscellaneous litter and total litter fall in Quercus leucotrichophora forests of the Kumaun Himalaya. Peak values of leaf, wood and miscellaneous litter fall occurred in May, June and November and December respectively. The total annual litter fall was 538.85 g m-2, of which leaf, wood and miscellaneous litters accounted for 72.35, 23.04 and 4.53% respectively. Monthly leaf litter fall, wood litter fall and total litter fall was positively related to the monthly temperature of the site.   Key words:  Kumaun Himalaya, leaf Litter fall, wood litter fall, miscellaneous litter fall, total litter fall, seasonal variation.

磨盘山天然次生林凋落物数量及动态研究

This study investigated the composition and spatiotemporal dynamics of litterfall at the community scale,on the basis of 144 square traps distributed uniformly in a 5.76 hm2permanent plot located in the deciduous broad-leaved forest of Mopan Mountain. The litterfall samples were collected monthly from April to November in 2006. The results showed that the annual litter production was 3039.6 kg / hm2. The proportion of leaves( 2499.2 kg / hm2) was 82.22%,and that of branches was 9.92%. The combination of flowers,fruits and barks was less than 5%. The leaf litters were from 42 tree species, accounting for 91.30% of the total number( 46) of the tree species in the plot. The main sources of leaf litterfall were Fraxinus rhynchophylla,Juglans mandshurica and Quercus mongolica,accounting for 82.97% of the overall amount. The litterfall exhibited evident spatial heterogeneity,with 200—400g litters in 99 traps and 600g litters in 2 traps. Some traps collected as many as 19 species,but most( 29 traps) did only 12 species. A single-peaked curve described the dynamic of monthly litterfall,and 69. 78% of litterfall occurred in September and October. Leaf litterfall peaked in autumn andexhibited the same temporal trend as the overall litterfall. However,different species peaked in a different manner,with Juglans mandshurica at August and September,Ulmus japonica at September and October,Acer mono at October,and Quercus mongolica at October and November,respectively.

Historical patterns of exotic earthworm distributions inform contemporary associations with soil physical and chemical factors across a northern temperate forest

Understanding environmental factors related to exotic earthworm distributions across invasion stages (i.e., introduction, colonization, regional spread) is critical for assessing long-term impacts on previously earthworm-free forests. Studies following earthworm community establishment in North America, however, remain limited. We address this by characterizing historical and current exotic earthworm distributions in a regionally representative aspen-dominated forest, where their presence was first documented in the early 1900s. We map historic earthworm distribution records in a 360-km2 area surrounding our current study site, and re-analyze data collected nearly 60 years ago to inform contemporary associations between species densities and environmental factors. Field surveys were conducted over two years (2008–2010) using 10 permanent plots, with concurrent measurements of environmental ‘effect factors’ determined by large-scale ecosystem processes (leaf litter inputs, soil physical properties, soil C and N content), and environmental ‘response factors’ likely impacted by earthworm activity over short time scales (annual litter mass loss and soil isotopic values). Present-day communities included five exotic species with varying densities: Lumbricus rubellus ≥ Lumbricus terrestris >> Dendrobaena octaedra ≥ Aporrectodea spp. (Aporrectodea trapezoides + Aporrectodea caliginosa). These species were also present in the landscape in the early to mid-1900s though shifts in species composition, particularly the movement of L. terrestris into upland forest soils, were evident. Over two years, earthworm community composition did not show strong temporal or spatial trends characteristic of incipient invasions. However, species-specific associations with environmental factors were observed: L. terrestris and L. rubellus densities were positively associated with soil C and N content, Acer rubrum (red maple) inputs, and soil moisture; and were negatively associated with Pinus strobus (white pine) inputs. D. octaedra, and Aporrectodea spp. densities were positively associated with % sand; and negatively associated with plot-to-road distance. Soil moisture and texture were significant drivers of earthworm species abundance in historical surveys, though associations with soil C were only evident for Aporrectodea spp. Contemporary associations between earthworm species and soil C and N content suggest greater nutrient limitation in upland forest soils, while the importance of plot-to-road distance suggests the persistence of dispersal limitation and repeated introductions as a mechanism maintaining population densities. Species-specific associations with environmental response variables were also observed, where: surface soil δ13C depletion was associated with Aporrectodea spp. and D. octaedra biomass; δ15N enrichment was associated with total earthworm biomass, but negatively associated with L. rubellus biomass; and increased leaf litter mass loss was associated with L. terrestris and juvenile biomass. As soil C and N pools were not higher in plots with higher earthworm biomass, these results suggest earthworm activity may influence soil nutrient cycling by decreasing turnover times of nutrient pools over the long-term. Our results characterize exotic earthworm distributions at scales relevant to forest ecosystem processes, and allow for future extrapolation of laboratory and controlled field studies assessing impacts on soil nutrient cycling across northern temperate forests.

Resource Pulses in Desert River Habitats: Productivity-Biodiversity Hotspots, or Mirages?

Resource pulses in the world's hot deserts are driven largely by rainfall and are highly variable in both time and space. However, run-on areas and drainage lines in arid regions receive more water more often than adjacent habitats, and frequently sustain relatively high levels of primary productivity. These landscape features therefore may support higher biotic diversity than other habitats, and potentially act as refuges for desert vertebrates and other biota during droughts. We used the ephemeral Field River in the Simpson Desert, central Australia, as a case study to quantify how resources and habitat characteristics vary spatially and temporally along the riparian corridor. Levels of moisture and nutrients were greater in the clay-dominated soils of the riverine corridor than in the surrounding sand dunes, as were cover values of trees, annual grasses, other annual plants and litter; these resources and habitat features were also greater near the main catchment area than in the distal reaches where the river channel runs out into extensive dune fields. These observations confirm that the riverine corridor is more productive than the surrounding desert, and support the idea that it may act as a refuge or as a channel for the ingress of peri-desert species. However, the work also demonstrates that species diversity of invertebrates and plants is not higher within the river corridor; rather, it is driven by rainfall and the accompanying increase in annual plants following a rain event. Further research is required to identify the biota that depend upon these resource pulses.

Litter production and nutrient cycling in two plantations and a Podocarpus falcatus dominated natural forest ecosystems in south-eastern highlands of Ethiopia

The production of litter plays a fundamental role in the biogeochemical cycle of organic matter and mineral nutrients in forest ecosystems. The amount of litter produced and nutrients returned, and their accumulation in the organic layers of Eucalyptus globulus and Cupressus lusitanica plantations, and an adjacent Podocarpus falcatus dominated natural forest were monitored over a one year period in Ethiopia. The objective of the study was to asses the general trends of nutrient cycling by litter fall under the two plantations relative to the natural forest. The results showed that annual litter production was significantly highest in the natural forest (4.4 t ha-1year-1) and least in Cupressus plantation (2.2 t ha-1year-1). Litter fall in the natural forest was of high quality and richer in most nutrients than the two plantations which behaved similarly. The annual fluxes of N, S, P, Ca, Mg and K were 1.3 to 2.3 times as much in the natural forest as in Eucalyptus and Cupressus. The organic layer under Cupressus had poor quality litter compared to Eucalyptus and natural forest which behaved similarly mainly due to the influence of the understorey vegetation on Eucalyptus organic layer. Although statistically not significant, dry mass accumulation in the organic layer of Cupressus was higher than in Eucalyptus and lower than in the natural forest, but the approximate residence time was in the order: Cupressus >natural forest>Eucalyptus. The organic layer in the natural forest had always the maximum quantity of nutrients compared to the two plantations. Except for Ca in which Cupressus far better, the other elements were accumulated in larger quantity in the Eucalyptus organic layer than in Cupressus. Overall, the results show that the Cupressus plantation is poor self fertilizing owing to the low quality homogenous materials which could result in a gradual impoverishment of the soil. Key words: Cupressus, Ethiopia, Eucalyptus, litter fall, nutrient cycling, organic layer.

Role of Arthropods in Maintaining Soil Fertility

In terms of species richness, arthropods may represent as much as 85% of the soil fauna. They comprise a large proportion of the meso- and macrofauna of the soil. Within the litter/soil system, five groups are chiefly represented: Isopoda, Myriapoda, Insecta, Acari, and Collembola, the latter two being by far the most abundant and diverse. Arthropods function on two of the three broad levels of organization of the soil food web: they are plant litter transformers or ecosystem engineers. Litter transformers fragment, or comminute, and humidify ingested plant debris, which is deposited in feces for further decomposition by micro-organisms, and foster the growth and dispersal of microbial populations. Large quantities of annual litter input may be processed (e.g., up to 60% by termites). The comminuted plant matter in feces presents an increased surface area to attack by micro-organisms, which, through the process of mineralization, convert its organic nutrients into simpler, inorganic compounds available to plants. Ecosystem engineers alter soil structure, mineral and organic matter composition, and hydrology. The burrowing by arthropods, particularly the subterranean network of tunnels and galleries that comprise termite and ant nests, improves soil porosity to provide adequate aeration and water-holding capacity below ground, facilitate root penetration, and prevent surface crusting and erosion of topsoil. Also, the movement of particles from lower horizons to the surface by ants and termites aids in mixing the organic and mineral fractions of the soil. The feces of arthropods are the basis for the formation of soil aggregates and humus, which physically stabilize the soil and increase its capacity to store nutrients.

시화호 인공습지에서 수생식물의 유기물 생산과 낙엽 분해

To provide the information for the wetland management considering the water treatment ability of macrophytes, the growth characteristics and primary production by reed (Phragmites australis) and cattail (Typha angustifolia), and the decomposition rate of organic matter produced were investigated in two sub-wetlands (Banweol and Donhwa wetlands) of the Sihwa Constructed Wetland (CW) with different chemistry of inflows. The shoot height of P. australis and Typha angustifolia began to increase in March, and reached its peaks in July and August (340cm and 320cm, respectively). The shoot density of P. australis ranging was higher than that of T. angustifolia (max. ). Standing biomass of P. australis ranged from , with maximal biomass in Banwol Upper Wetland. And it was larger in upper wetlands than lower wetlands. On the other hand standing biomass of T. angustifolia () was similar to that of P. australis in Banwol Upper Wetland. Primary productivity of P. australis was in the order of Banwol Upper Wetland () > Donghwa Lower Wetland () > Banwol Lowerr Wetland () Donghwa Lower Wetland (), and that of T. angustifolia () was higher than P. australis. Annual production of organic matter produced by P. australis and T. angustifolia was 845 ton DM/yr (423 ton C/yr), and about 90% was comprised of that by P. australis. From the litter decomposition rate (k) (P. australis: leaf 0.0062/day, stem 0.0018/day; T. angustifolia: leaf 0.0031/day, stem 0.0018/day), leaf was rapid degraded compare to stem in both P. australis and T. angustifolia. The litter decomposition rate of leaf was two times rapid P. australis than T. angustifolia, whereas that of stem was same in both. Annual litter decomposition amount of P. australis than T. angustifolia was 285 ton C/yr(67.3% of organic matter produced by macrophytes), indicating that 32.7% of organic matter produced by macrophytes is accumulated in the Sihwa CW.

Rapid litter production and accumulation in Bornean mangrove forests

Litter fall and accumulation were measured weekly for one year (January–December 2007) at five mangrove forests within the Apar‐Adang Nature Reserve, East Kalimantan, Indonesia. Three forests were located near the sea edge, each co‐dominated by combinations of Sonnertia alba, Rhizophora apiculata, and Bruguiera parviflora; two forests were co‐dominated by Ceriops decandra, Exocoecaria agallocha, and Bruguiera sexangula (site IV), and by B. parviflora and B. sexangula (site V) and located further inland but subjected to intermittant freshwater inputs. Mean rates of annual litter production at forests I to V were 20.3, 19.7, 27.2, 24.2 and 27.6 Mg DW ha−1 yr−1 (mean of all forests = 23.7 Mg DW ha−1 yr−1) and rates of litter accumulation were 44.4, 50.2, 45.9, 61.3 and 66.2 Mg DW ha−1 yr−1 (mean of all forests = 57.8 Mg DW ha−1 yr−1), respectively, exhibiting peaks in the wet and dry seasons. Litter accumulation was greater than litter fall due to tidal advection of litter from forests closer to the sea edge coupled with slow decay rates. These rates of aboveground litter production and accumulation are the highest recorded for mangroves and higher than rates measured in tropical humid evergreen forests, suggesting that large expanses of equatorial mangrove forest, such as those on Borneo, may constitute an immense sink for coastal carbon.

Linking litter decomposition of above‐ and below‐ground organs to plant–soil feedbacks worldwide

Summary Conceptual frameworks relating plant traits to ecosystem processes such as organic matter dynamics are progressively moving from a leaf‐centred to a whole‐plant perspective. Through the use of meta‐analysis and global literature data, we quantified the relative roles of litters from above‐ and below‐ground plant organs in ecosystem labile organic matter dynamics. We found that decomposition rates of leaves, fine roots and fine stems were coordinated across species worldwide although less strongly within ecosystems. We also show that fine roots and stems had lower decomposition rates relative to leaves, with large differences between woody and herbaceous species. Further, we estimated that on average below‐ground litter represents approximately 33 and 48% of annual litter inputs in grasslands and forests, respectively. These results suggest a major role for below‐ground litter as a driver of ecosystem organic matter dynamics. We also suggest that, given that fine stem and fine root litters decompose approximately 1.5 and 2.8 times slower, respectively, than leaf litter derived from the same species, cycling of labile organic matter is likely to be much slower than predicted by data from leaf litter decomposition only. Synthesis. Our results provide evidence that within ecosystems, the relative inputs of above‐ versus below‐ground litter strongly control the overall quality of the litter entering the decomposition system. This in turn determines soil labile organic matter dynamics and associated nutrient release in the ecosystem, which potentially feeds back to the mineral nutrition of plants and therefore plant trait values and plant community composition.

Coarse Woody Debris Stimulates Soil Enzymatic Activity and Litter Decomposition in an Old-Growth Temperate Forest of Patagonia, Argentina

In most temperate forest ecosystems, tree mortality over time generates downed logs that accumulate as coarse woody debris (CWD) on the forest floor. These downed logs and trunks have important recognized ecosystem functions including habitat for different organisms and long-term organic C storage. Due to its recalcitrant chemical composition and slow decomposition, CWD can also have direct effects on ecosystem carbon and nutrient turnover. CWD could also cause changes indirectly through the physical and chemical alterations that it generates, although it is not well-understood how important these indirect effects could be for ecosystem processes and soil biogeochemistry. We hypothesized that in an old-growth mature forest, CWD affects carbon and nutrient cycles through its “proximity effects”, meaning that the forest floor near CWD would have altered soil biotic activity due to the environmental and biogeochemical effects of the presence of CWD. We conducted our study in an old-growth southern beech temperate forest in Patagonia, Argentina, where we estimated and classified the distribution and mass, nutrient pools and decay stage of CWD on the forest floor, and evaluated its impact on litter decomposition, soil mites and soil enzymatic activity of carbon and phosphorus-degrading enzymes. We demonstrate here that CWD in this ecosystem represents an important organic carbon reservoir (85 Mg ha−1) and nitrogen pool (0.42 Mg ha−1), similar in magnitude to other old-growth forests of the Northern Hemisphere. In addition, we found significant proximity effects of CWD, with increased C-degrading soil enzyme activity, decreased mite abundance, and more rapid litter decomposition beneath highly decayed CWD. Considered at the ecosystem scale in this forest, the removal of CWD could cause a decrease of 6% in soil enzyme activity, particularly in the summer dry season, and nearly 15% in annual litter decomposition. We conclude that beyond the established importance of CWD as a long-term carbon reservoir and habitat, CWD contributes functionally to the forest floor by influencing the spatial heterogeneity of microbial activity and carbon and nutrient turnover. These proximity effects demonstrate the importance of maintenance of this ecosystem component and should be taken into consideration for management decisions pertaining to carbon sequestration and functional diversity in natural forest ecosystems.

我国中东部不同气候带成熟林凋落物生产和分解及其与环境因子的关系

Production and decomposition of plant litter is one of the most important processes in terrestrial ecosystems.This process could be affected by climate,which elucidates that the spatial patterns and environmental regimes,which regulate the process,are essential to understand the mechanism of ecosystem functioning in both local and broad scales.However,the pattern of the process in large scales along environmental gradients in mid-and eastern China was poorly understood.The aim of the present work was to quantify litter production and its decomposition rate in forest ecosystems from subtropical to temperate zones with a view to gaining further insights into the recycling of above-ground organic matter.Data from 72 plots in six major forest types in China was used to clarify litter production and decomposition in six forest ecosystems and their relations with environmental factors in different climatic zones including Huzhong in Heilongjiang province,Mt.Changbai in Jilin province,Mt.Dongling in Beijing municipality,Mt.Gutian in Zhejinag province,Shennongjia in Hubei province,and Dujiangyan in Sichuan province.The storage of litter fall was in the sequence of: ShennongjiaDujiangyan Mt.gutianMt.DonglingMt.ChangbaiHuzhong.The annual litter production for Shennongjia,Dujiangyan,Mt.gutian,Mt.Dongling,Mt.Changbai,Huzhong were averaged at 910.98,830.18,574.06,396.19,374.64,and 249.29 gm-2a-1,respectively.Annual litter fall production was highly significant in relation to forest type and positively related to mean annual temperature,but was not significantly related to mean annual precipitation.There were two litter fall peaks in the subtropical forests in a year,one in spring(from April to May) and the other in autumn(October and November),while there was just on peak in the cold temperate,temperate and warm temperate forests,which occurred in autumn(from September to October).The litter decomposition rate(k) was consistent with litter fall production,and the k value decreased with increasing latitude.The annual litter decomposition rate(k) for Shennongjia,Dujiangyan,Mt.gutian,Mt.Dongling,Mt.Changbai,Huzhong were averaged at 0.13,0.26,0.36,0.79,0.92,and 0.8,respectively.A simple regression model was capable of explaining the majority of climatic effects on litter production and the decomposition rates of various litter types tested in different environments over geographical regions.In conclusion,mean annual temperature is the most important environment variable affecting litter decomposition rate,followed by mean annual precipitation.