两种相手蟹对不同红树植物叶片取食的偏好性

大型底栖动物是红树林生态系统中重要的消费者,在红树林的营养物质转化和能量传递过程中具有重要作用。通过设置室内模拟饲喂实验,研究了华南沿海红树林大型底栖动物的常见种--无齿相手蟹(Sesarma dehaani)和双齿相手蟹(S.bidens)对外来红树植物无瓣海桑(Sonneratia apetala)和乡土红树植物秋茄(Kandelia obovata)、桐花树(Aegiceras corniculatum)凋落叶片的取食特性。结果表明,随着淋溶作用的进行,各树种叶片中单宁含量和C/N均逐渐降低,两个数值的变化幅度以秋茄叶片最大,分别达(45.85±7.74)g·kg-1和11.24%,无瓣海桑为(45.15±11.14)g·kg-1和2.43%,桐花树则为(18.75±15.15)g·kg-1和-1.36%。随着叶片中单宁含量和C/N的降低,两种相手蟹的取食量相应地呈逐渐上升的趋势,双齿相手蟹从3.097g到10.079g和无齿相手蟹则从2.480g到8.723g。两种相手蟹种间的取食特性差异不显著(P0.05),但对不同树种的取食上却存在显著差异,其中对桐花树的取食偏好性显著差于无瓣海桑和秋茄(P0.01),这主要与桐花树叶片的高单宁含量和低营养价值有关。研究结论说明大面积引种外来物种无瓣海桑将可能对华南沿海红树林生态系统的食物链结构产生潜在影响,并为红树林的生态恢复和科学造林提供了参考。     

四种红树植物根茎叶的碳氮磷化学计量特征

以漳江口红树林的秋茄(Kandelia candel)、木榄(Bruguiera gymnorrhiza)、桐花树(Aegiceras corniculatum)和老鼠簕(Acanthus ilicifolius)为研究对象,对其根、茎、叶中的碳(C)、氮(N)、磷(P)含量以及生态化学计量学特征进行分析。结果表明:秋茄、桐花树、老鼠簕3种植物各器官中的C含量均表现为茎、叶显著大于根,秋茄、木榄、桐花树3种植物的N、P含量均表现为叶茎根;桐花树、老鼠簕不同器官的C含量变异系数均表现为根叶茎,秋茄、木榄、老鼠簕3种植物N含量的变异系数均表现为根、茎大于叶,秋茄、木榄、桐花树3种植物P含量的变异系数均表现为根、茎大于叶;秋茄、木榄、老鼠簕C∶N的变异系数为根、茎大于叶; 4种植物中,老鼠簕根、叶的P含量显著高于其他3种植物,茎的P含量略高于其他3种植物,根C、N、P与叶C、P的变异系数均大于其他3种植物; 4种红树植物叶的C∶N∶P质量比(151∶9∶1)显著小于根(187∶4∶1)和茎(239∶5∶1),叶的C、N和P的生态化学计量特征相对稳定。分析红树植物不同器官养分元素间的分配规律,可为大尺度的红树林生态化学计量学研究提供理论基础,并为红树植物的保护与可持续经营提供科学依据。     

闽江口秋茄凋落叶分解碳氮磷元素动态特征与水解酶活性

凋落物水解酶活性和环境要素对凋落物的分解有重要影响。为研究秋茄凋落叶分解过程中碳(C)、氮(N)、磷(P)元素动态特征及水解酶活性变化,采用凋落物分解袋法,以闽江口粗芦岛红树林湿地20年生秋茄(Kandelia obovata)为研究对象,探讨秋茄凋落叶在秋茄(主场)和互花米草(Spartina alterniflora Loisel.)(客场)生境分解的差异。结果表明:①整个分解期间,主场生境秋茄凋落叶累计质量损失率显著高于客场生境(P0.05),两生境下累计质量损失率和分解速率随分解时间变化差异性明显(P0.01)。主客场生境对比下,凋落叶C、N、P含量及其化学计量比没有显著性差异(P0.05),但均随分解时间推移发生显著性变化(P0.01)。②凋落物累计质量损失率与TC含量、C/N、酸性磷酸酶(AP)活性呈显著负相关关系(P0.01)、与TN显著正相关(P0.01),分解速率与TP呈显著正相关关系(P0.01)。③AP活性与凋落物C、N、P含量及C/N、C/P显著相关(P0.05),与土壤温度呈显著正相关关系(P0.01)。β-葡萄糖苷酶(βG)和β-N-乙酰氨基葡萄糖苷酶(NAG)均与N/P呈显著正相关关系(P0.01)、与土壤电导率负相关关系明显(P0.05),纤维素水解酶(CBH)与TC呈显著正相关关系(P0.05)。说明秋茄凋落叶的分解与部分水解酶活性和自身养分含量相关,并受到土壤环境因子的影响较大;凋落物分解过程中,水解酶活性会受到分解底物和土壤环境因子环境限制。     

泉州湾互花米草入侵滩涂中人工种植秋茄幼苗的叶片营养元素动态特征

于福建泉州湾洛阳江河口湿地保护区内互花米草入侵红树林生态修复滩涂内,采集并测定了种植后第2年的红树植物秋茄(Kandelia obovata)生长周期内(2017年6月—2018年3月)的叶片C、N、P含量及地上生物量,以阐明2年生秋茄的C、N、P营养元素含量与化学计量比随时间动态特征及其控制因子,了解红树植物秋茄在互花米草入侵地区生长第2年的养分利用与元素限制条件。结果显示:2年生秋茄叶片全碳含量为363.12～425.75 g·kg^-1;叶全氮含量为17.37～18.22 g·kg^-1;叶全磷含量为1.33～4.06 g·kg^-1。秋茄叶片C∶N、C∶P、N∶P随季节时间变化均呈现先下降后上升的趋势。研究表明,泉州湾滨海湿地秋茄在第2年生长周期内对营养元素的利用效率较好,氮元素可能是泉州湾河口湿地2年生秋茄的主要限制元素。研究结果为利用秋茄替代互花米草的生态入侵综合治理及红树林的人工种植养护提供了科学依据。     

杉木人工林下杉木、楠木和木荷叶凋落物分解特征及营养元素含量变化的动态分析

采用网袋法,对0～360 d内杉木[Cunninghamia lanceolata (Lamb. ) Hook. ]、楠木[Phoebe bournei (Hemsl. ) Yang]和木荷(Schima superba Gardn. et Champ. )叶凋落物在杉木人工林下的分解特征及营养元素(N、P、K和C)含量的变化动态进行了比较分析.结果显示,经过360 d的分解,杉木、楠木和木荷叶凋落物的干质量损失率分别为40.6%、42.0%和51.6%,平均腐解率分别为0.001 3、0.001 6和0.002 0 d-1,叶凋落物的分解半衰期分别为537、482和372 d.在整个分解过程中,3个树种叶凋落物中P含量总体上均呈波动且缓慢的上升趋势;K含量在分解过程前期均急剧下降,然后随分解时间的延长变化趋缓;N含量变化差异较大,随分解时间的延长,杉木叶凋落物中N含量呈缓慢上升趋势,另外2个树种叶凋落物中N含量总体上呈先下降后上升的变化趋势;C含量基本上呈前期上升、中期下降、后期又略有上升的趋势,而C/N比则呈前期略上升而后期逐渐下降的趋势.3个树种叶凋落物分解过程中N、P、K和C的释放率及其动态变化也存在一定差异.3个树种叶凋落物中K的释放率均较高、变化趋势较接近,且均处于净释放状态;杉木叶凋落物中N、P和C的释放率总体上低于另2个树种,且木荷叶凋落物中N、P和C基本均处于单调净释放状态,而杉木叶凋落物中N、P和C以及楠木叶凋落物中P和C在分解过程前期均略呈净富集状态,之后N和C基本上呈净释放状态、P则呈波动式净释放状态.结果表明,在杉木人工林下,阔叶树种(楠木和木荷)叶凋落物比针叶树种(杉木)叶凋落物易分解,且阔叶树种叶凋落物中的营养元素也较易释放.     

岩溶区和非岩溶区两种优势植物凋落叶分解的比较研究

应用野外分解网袋法对岩溶地区和非岩溶地区两种优势树种桂花和青冈栎凋落叶的分解速率和养分释放规律进行研究。结果表明:分解1年后,凋落叶失重率桂花大于青冈栎,同一物种岩溶区大于非岩溶区。凋落叶各元素浓度随分解时间变化也有一定差异,C含量均表现为初期上升,后下降,最后上升的趋势;N含量前半年呈波动状态,后半年逐渐上升;P含量处波动状态,总体呈上升趋势。N、P含量和凋落叶失重率均表现为极显著正相关,而C:N、C:P、N:P与凋落叶失重率呈极显著负相关(P<0.01),说明凋落叶分解过程中失重率与N、P含量及C:N、C:P、N:P关系密切。凋落叶桂花N、P含量比青冈栎高,分解速率也比较快。     

几种水生植物腐解过程的比较研究

研究水生植物腐烂分解过程及其养分动态对认识水生态系统物质循环过程具有重要意义。通过室内植物分解模拟试验,对6种水生植物的腐解过程及腐解残余物成分的变化进行了比较研究。结果表明,在64 d的腐解过程中,浮叶植物的分解速率最快,沉水植物其次,挺水植物最慢;同种植物的分解速率及残余物成分变化在不同生物量密度组间存在一定差异,但总体趋势一致。分解过程中,植物残余物中P、纤维素、木质素含量的变化趋势种间差异较小,总体上P含量先迅速下降后缓慢上升,纤维素含量先下降后趋于稳定,木质素含量先上升后趋于稳定;植物残余物中C、N、半纤维素含量在分解初期种间的变化趋势不同,而分解后期则均为C含量上升,N、半纤维素含量趋于稳定。相关性分析结果表明,总体上,在整个分解周期中,初始N、P含量越大分解越快,初始纤维素、半纤维素、木质素含量、C/N、C/P、木质素/N等越大分解越慢;植物腐解不同阶段的质量指标对分解速率的影响有所不同,在分解前期,残余物中N含量越高分解越快,半纤维素含量、C/N、木质素/N越高,分解越慢,而后期木质素含量越高分解越慢,其它因子影响较小。     

两种红树叶的几种酶的生理特性与海滩盐度的相关性初探

本文是福建九龙江口红树林研究的一部分,主要讨论两种红树植物(秋茄,桐花树)叶片中的几种酶对海滩盐度(3—12‰范围内)变化的反应,测定结果如下：1,桐花树叶片过氧化物酶同工酶和细胞色素氧化酶同工酶的含量对土壤盐度变化的反应表明：土壤盐度(3—12‰)提高,过氧化物酶和细胞色素氧化酶同工酶的谱带加深、加宽,而且谱带中出现新酶带。 2．当海滩盐度提高时,桐花树叶片的过氧化物酶的活性提高,秋茄叶片的乙醇酸氧化酶的活性减弱。 3．两种红树植物叶绿素含量与土壤盐度相关性显示出：当土壤盐度在3—8‰范围时,叶绿素含量变化不大;8—10‰时有一个高峰,大于10‰时又下降。可能红树植物对海滩盐度适应有一个临界值。     

黄土丘陵区人工林刺槐和油松凋落叶在不同降雨时期的分解特征

凋落物分解是维持生态系统养分循环和能量流动的关键过程,但在雨热同期的黄土丘陵区,不同降雨时期凋落物基质质量动态对该区不同树种凋落物分解速率的影响还不清楚。采用凋落物分解袋法,基于野外原位分解实验分析黄土丘陵区主要人工林刺槐（Robinia pseudoacacia Linn.）和油松（Pinus tabulaeformis Carr.）凋落叶在不同降雨时期的分解特征和分解过程中凋落叶基质质量的变化与分解速率之间的关系。研究结果发现：（1）经过391 d的分解,刺槐凋落叶的平均质量损失速率为（51.0±8.44）mg/d,显著地高于油松凋落叶（36.7±4.83）mg/d;雨季期间两树种凋落叶的质量损失速率均显著地高于旱季,其中夏季多雨期间凋落叶的质量损失速率最高,冬季微量降雨期间质量损失速率最低。（2）在整个分解过程中两树种凋落叶C和N含量都表现为净释放且主要发生在雨季,P含量表现为释放与富集交替进行;刺槐凋落叶C/N比、C/P比和N/P比呈波动的趋势,油松凋落叶C/N比则显著地增加且在夏季多雨期出现峰值,C/P比呈波动的状态,N/P比变化较小。（3）不同降雨时期刺槐凋落叶的质量损失速率与凋落叶P含量动态显著正相关,与C含量、C/P比和N/P比动态显著负相关。油松凋落叶质量损失速率与C/N比动态显著正相关,与C、N含量动态显著负相关,与N/P比动态呈负二次函数的关系。这些结果说明黄土丘陵区刺槐和油松凋落叶在不同降雨时期分解速率之间的差异显著且两树种凋落叶的分解都集中在雨季期间;此外凋落叶分解主要受到凋落叶N含量和N/P比动态变化的制约,与刺槐凋落叶相比,N含量与N/P比对油松凋落叶的限制作用更强。     

广西北部湾典型海岛红树林的结构特征、空间格局及种间种内关联性

为研究广西北部湾茅尾海自然保护区海岛红树林群落的空间点格局和演替规律,在典型红树林海岛设置调查样地,以样地内的桐花树(Aegiceras corniculatum)、秋茄(Kandelia obovata)、白骨壤(Avicennia marina)等红树植物为研究对象,构建单变量函数的完全空间随机模型、异质泊松模型与双变量函数的环形转变模型,分析3种红树林种群的结构特征、空间格局及种内种间关联性。结果发现：(1)桐花树种群的小树和中树的个体数目较多,种群年龄结构呈金字塔型,种群处于增长状态;秋茄种群的中树个体数目较多,种群结构呈钟型,种群数量处于稳定状态;白骨壤个体数相对较少,且幼树较少老树较多,种群更新受阻,种群结构呈纺锤型,属于衰退型种群。(2)红树林群落整体上呈现出空间集聚的分布特征,从不同种群的集聚程度来看：桐花树>白骨壤>秋茄。(3)随着空间尺度的增大,红树林群落在空间分布上依次表现出聚集、随机和均匀3种特征。(4)桐花树与秋茄、白骨壤的种间关系随着尺度增加均表现为空间无关联性-空间负关联性-空间无关联性的演变特征,秋茄与白骨壤的种间关系则为全尺度的空间无关联性。(5)桐花树种内不同龄级之间存在空间正关联性、空间无关联性和空间负关联性,秋茄种内不同龄级之间均表现出空间无联性,白骨壤种群则在不同龄级之间均出现空间正关联性。(6)红树植物种群的空间格局受到自身繁殖特性、生境异质性、种内和种间竞争、病虫害等多种因素的影响。红树林人工种植和恢复需要结合沿海地区的自然生态条件,按照红树林种群的适应形态学特点、群落类型和自然演替规律,种植乡土红树植物,适当引进外来物种,研制出近似天然的人工红树林林分结构,提高群落的生物多样性和群落稳定性,发挥红树林湿地生态系统的生态环境效应。     

人工生境条件下几种红树植物的净初级生产力比较研究

选择3种红树植物海桑(Sonneratia caseolaris)、秋茄(Kandelia candel)和桐花树(Aegiceras corniculatum),每种分别按45%、30%和15%的面积比例种植于滩涂海水养殖塘.种植后连续2年对红树植物进行生态监测.结果表明,海桑增高457.0cm,基径增加86.1mm,成活率92.9%;桐花树高、基径分别增长2.1cm和36.5mm,成活率93.9%;秋茄成活率44.7%,增高20.4cm、基径增加2.4mm,说明在不受自然潮汐影响的人工生境条件下,海桑和桐花树对环境的适应能力强,生长较好,秋茄的生长适应性较差.据不同时期树高、基径与干、枝、叶、根的生物量,求得植物各器官生物量与树高、基径的回归方程,分析了3种红树植物的生物量与净初级生产力.海桑单位面积生物量5597.8g·m^-2,桐花树962.5g·m^-2,秋茄66.0g·m^-2.生物量在植物各器官的分配按大小排序,海桑为树干＞树枝＞树根＞树叶;桐花树为树叶＞树枝＞树干＞树根;秋茄为树干＞树根＞树叶＞树枝.单位面积净初级生产力海桑为7051.5g·m^-2,桐花树1105.8g·m^-2,秋茄93.0g·m^-2.高生产力伴随高归还量,凋落物归还量占净初级生产力的比重为海桑20.5%、桐花树15.4%、秋茄7.%.     

秋茄红树植物落叶分解的碎屑能量研究

测定了红树植物秋茄（Ｋａｎｄｅｌｉａ ｃａｎｄｅｌ （Ｌ．） Ｄｒｕｃｅ）落叶在不同季节分解过程中碎屑的热值和富能有机化合物的变化。结果表明,季节间落叶的热值差别不大,平均为１９．６３ ｋＪ／ｇ干重或２１．５５ ｋＪ／ｇ 去灰分干重。各季节的落叶在其分解后的碎屑的热值均明显提高,且夏秋季快于冬春季,但它们与分解程度有相应的相关关系：分解初期上升,后期稍降,最大值出现在半分解期（失重５０％ ）附近。碎屑的最大热值平均比落叶的热值提高１７．６７％ （干重热值）或１４．３５％ （失灰分干重热值）。分解中总能量的耗散稍慢于干物质的损失。随分解的进行,碎屑中粗蛋白、粗脂肪、粗纤维的能量增大,而无氮浸出物的能量减少。     

Studies on Detritus Energy During the Decomposition of Kandelia candel Leaf Litter

Changes of caloric values and energy-rich organic compounds were studied in the detritus derived from mangrove Kandelia candel (L.) Druce leaf litter during the various in situ seasonal decomposition in Jiulong River Estuary, Fujian, China. The results showed that the caloric values varied little among the seasonal fallen leaves being a mean of 19.63 kJ/g dry wt or 21.55 kJ/g AF dry wt, the caloric values of detritus increased remarkably after decomposition but they more rapidly in summer and autumn than in winter and spring. The change was well in agreement with the degree of decomposition, being increased in the early decomposition period and slightly decreased in the later, with a peak at about the half-time of decomposition (50% weight loss). The maximum was averagely 17.67% of dry weight and 14.35 % of ash-free dry; weight basis over the initial values. The dissipation of total energy was somewhat slower than the loss of dry matter. As decomposition proceeds the energy of detritus was more and more contributed by raw protein, raw fat, raw fibers rather than by N-free extract. Therefore it is suggested that detritus at half-time of decomposition should be more important to marine detritivores from the viewpoint of energy supplement.     

Decomposition of leaf and root litter of Avicennia marina at Westernport Bay,Victoria, Australia

After 3 days in sea water, leaching losses caused a 13% reduction in the weight of new leaf litter of Avicennia marina (Forsk.) Vierh., and a 20% reduction of N, 35–40% of P, 60–85% of K, 30–40% of Mg and 0–12% of Ca. In the field, leaf litter in litter bags lost 80–90% of its initial weight and 89–99% of its initial K, 90–95% of its Mg, 85–90% of its P, 70–80% of its Ca and 60–80% of its N after 230–270 days. During this same period, Avicennia fibrous- and main-root litter in bags buried at a depth of 10–15 cm lost an average of 10–15% and 60% of their initial weight, respectively. Fibrous roots lost 80% of their K, 40–50% of their P, 15% of their N, 10–15% of their Mg and 5–10% of their Ca. Elemental losses from main roots ranged from 90% for K to 30% for Mg, with P, Ca and N losses of 70, 70 and 50%, respectively. Litter decomposition curves for leaf litter and fibrous-root litter begun at different times were not significantly different. A study with unbagged leaf litter indicated that crabs ate about 50% of the litter retained in the mangrove zone. Unbagged litter not eaten by crabs lost weight more rapidly than bagged litter because it lost leaf fragments more readily as it aged. We estimate from our studies and field observations that about 40% of the leaf litter produced each summer is exported from the mangrove zone in the form of whole leaves, particulate organic matter and dissolved organic matter. Root litter is neither exported from the mangrove zone nor eaten by crabs.     

盐度对秋茄凋落叶分解过程中物质与能量动态的影响

在室内人工模拟潮汐, 研究了4种盐度(0、10‰、25‰和35‰, 分别代表淡水、低盐、中盐和高盐)下秋茄(Kandelia candel)凋落叶分解过程中物质与能量动态的差异。结果表明, 高盐处理下的失重率和平均分解速率显著低于淡水和低盐处理, 而高盐下的半分解理论值则高于其他处理; 盐度对分解过程中的残叶氮磷变化动态有显著影响, 其中, 残叶氮的释放速率在实验后期会随着盐度的升高而上升, 高盐度下残叶总氮含量显著低于低盐或淡水处理; 而在分解第1周, 淡水或低盐处理能加速磷的释放, 但中高盐度残叶中总磷含量最终会低于淡水和低盐处理; 盐度同样能对残叶热值产生显著影响, 淡水和低盐处理下的碎屑热值要显著高于高盐处理下的残叶热值, 但不同盐度下分解的能量损失差异不显著。     

人工红树林中黑口滨螺和黑线蜒螺分布的差异性

研究了福建九龙江河口不同林龄、不同红树种类的人工林中黑口滨螺（Littoraia elanostoma）和黑线蜒螺（Nerita lineata）的分布情况.结果表明,黑线蜒螺主要分布于秋茄林内,且其生物量随林龄增加而增加;桐花树林内黑口滨螺的生物量和密度均大于林龄相近的秋茄林,但个体大小则小于秋茄林.黑口滨螺的生物量在桐花树林内随林龄增加呈现先增加后减少的趋势,而在秋茄林内则随林龄增加而减少.这种差异性反映了人工红树林植物种类及其演替过程对腹足类动物分布的影响.     

Phosphorus dynamics during decomposition of mangrove (Rhizophora apiculata) leaves in sediments

Rhizophora apiculata leaf litter decomposition and the influence of this process on phosphorus (P) dynamics were studied in mangrove and sand flat sediments at the Bangrong mangrove forest, Phuket, Thailand. The remaining P in the mangrove leaf litter increased with time of decomposition to 174% and 220% of the initial amount in the litter in sand flat and mangrove sediment, respectively, although about 50% of the dry weight had been lost. The incorporation of P into the litter was probably associated with humic acids and metal bridging, especially caused by iron (Fe), which also accumulated in considerable amounts in the litter (5-10 times initial concentration). The addition of leaves to the sediment caused increased concentrations of dissolved reactive phosphate (DRP) in the porewater, especially in sand flat sediment. The DRP probably originated from Fe-bound P in the sediment, because decomposition of buried leaf litter caused increased respiration and reduced the redox potential (E_h) in the sediments. Binding of P to refractory organic material and oxidized Fe at the sediment-water interface explains the low release of DRP from the sediment. This mechanism also explains the generally low DRP concentration in the mangrove porewater, the low nutrient content of the R. apiculata leaves, but also the higher total sediment P concentration of the mangrove sediment as compared to sediments outside the mangrove. Both the low release rates for DRP from the sediment and the accumulation of P associated with leaf litter decomposition tend to preserve P in the sediments.     

Effects of leaf litter addition on meiofaunal colonization of azoic sediments in a subtropical mangrove in Hong Kong

The responses of major meiofaunal taxa and nematode species assemblage to the decaying leaf litter of the mangrove Kandelia candel were investigated through a field colonization experiment in subtropical Hong Kong. Sixty-four replicate azoic and organic-free sediment cores were treated with leaf litter additions of 0x, 0.5x, 1x and 2x natural sediment organic concentration, respectively, and retrieved 1, 10, 30 and 60 days post-placement. Replicate cores of ambient sediment were also taken at each sampling date to provide baseline information. Results of ANOVAs suggested that either different meiofaunal taxa responded to the leaf litter in different ways or the response of the same taxon changed over decomposition time. Multivariate ordination performed on nematodes revealed an alteration in community structure after 10, 30 and 60 days between controls and treatments. This alteration was attributed to some deposit feeding nematodes, particularly a bacterivorous species, Diplolaimella sp., which bloomed in all the cores treated with leaf litter, testifying to the important role such meiofauna plays in the process of detritus decomposition.     

无瓣海桑、海桑、秋茄红树人工林群落动态及物种多样性研究

对红树植物无瓣海桑、海桑、秋茄3种人工林群落动态及物种多样性特征的系统研究结果表明,无瓣海桑群落和海桑群落的乔木层明显分为上层和中层两个亚层,上层木为无瓣海桑或海桑,中层木主要为秋茄和桐花树;秋茄群落的乔木层为单一层次,基本由秋茄组成．在无瓣海桑群落和海桑群落中,优势种群无瓣海桑或海桑仅有高龄级个体存在,未出现自然更新现象;秋茄和桐花树为旺盛增长种群,有可能成为优势种群,表明无瓣海桑和海桑为先锋造林树种,在裸滩种植可以促进其它红树植物的天然定居生长;在秋茄群落中,秋茄为旺盛增长种群,能够自然：更新演替,桐花树和海莲属初生增长种群．无瓣海桑群落和海桑群落的物种组成和物种多样性指标较接近,基本包含秋茄群落中的主要物种秋茄、桐花和海莲。表明无瓣海桑和海桑能与这些物种协调共生,同时种植无瓣海桑或海桑可以形成多样化的红树林群落;无瓣海桑群落和海桑群落在形成初期,种植密度较大时,物种多样性较高;密度相近时。形成初期随林龄的增加。其物种多样性略有提高．     

Litter decomposition of woody species in shrublands of NW Patagonia: how much do functional groups and microsite conditions influence decomposition?

The study examined the effects of leaf traits, soil microsite, and microclimate characteristics on litter decomposition of the dominant species in two functional groups (FG), deciduous and evergreen, in shrublands in NW Patagonia, Argentina. Leaf traits considered were nutrient concentration (C, N, P, C/N, and N/P) and physical characteristics (area, strength, specific leaf area, and dry matter content). Soil microsite characteristics measured were pH, C, N, P, C/N and water retention capacity, while soil microclimate characteristics recorded were soil and air, temperature and moisture, and solar radiation. Five evergreen and five deciduous woody shrub species were selected. During 1 year, litter and microsite properties were measured below canopy: (i) senescent leaf chemical and physical properties, and the quantity as well as field decomposition of litter and (ii) soil chemistry, and soil and air physical properties. The factors controlling litter decomposition were different for each FG. In deciduous species, C/N ratio had a negative effect on decomposition. In evergreen species, decomposition was affected negatively by leaf carbon and dry matter content. Litter decomposition depended exclusively on the inherent senescent leaves traits. The common decomposition pattern between species of both FG could be attributed to similar leaf traits and the correlation between variables that control decomposition in both groups. Plant nutrient inputs associated with the litter decomposition process did not explain the soil nutrient content. These results suggest that other organic matter sources (roots, branches, and fruits) are more important than leaves on soil fertility.