Environmental relations and ecological responses of some higher plant species on rock cliffs in northern Tasmania

Abstract Gravity, moisture availability and shade exert a major control over the distributions of vascular plant species on sandstone cliffs in the Great Western Tiers, northern Tasmania. The vegetation is dominated by ferns, some of which are almost always restricted to cliffs, with invasion of shrub and tree species where soil has been able to accumulate. Although it might be expected that species commonly found over a wide range of vegetation types could displace obligate cliff dwellers, this potential is rarely fulfilled. The vertical nature of the environment precludes the loss of cliff obligates, as soil-vegetation mats peel off in part of a truncated and cyclic successional process. Experimental work and field monitoring of growth and mortality in single species and mixed stands showed that the cliff obligate fern Blechnum vulcanicum (Blume) Kuhn is slower growing, more drought resistant and less responsive to fertilizer than its non-obligate associate, B. wattsii Tind.     

Fish community structure response to major habitat changes within the littoral zone of an estuarine coastal lake

Synopsis The littoral environment and fish fauna of Swartvlei, an estuarine lake, was monitored for four years during which major habitat changes occurred. Initially (1979) the zone was dominated by the submerged macrophytes Potamogeton pectinatus, Chara globularis and Lamprothamnium papulosum. This plant community was replaced by filamentous algal mats during 1980 and with the disappearance of these mats in 1981 the littoral zone was transformed into a sandy habitat. There was a highly significant decline in the numbers of fishes in the littoral zone between the macrophyte and sand phases but no significant decrease in fish biomass between the two phases. Analysis of gill net catches revealed an increase in the CPUE of the family Mugilidae between the macrophyte and sand phases but a decline in the CPUE of vegetation associated species such as Monodactylus falciformis and Rhabdosargus holubi over the same period. The increase in mullet stocks during the sand phase was attributed to epipsammic micro-algal production and the input of allochthonous detritus during the 1981 floods. The three fish species diversity indices used in this study showed minor fluctuations between the habitat phases and these variations were related to changes in the equitability of distribution between the individual species within each habitat type. The numbers of fish species recorded during the macrophyte, algal mat and sand phases varied by less than 20%. The resilience of estuarine fishes to major alterations in their environment was illustrated by the fact that all fish species recorded at the beginning of 1979 were present at the end of 1982, despite major habitat and food resource changes.     

Is succession in wet calcareous dune slacks affected by free sulfide?

Abstract. Consequences of sulfide toxicity on succession in wet calcareous dune slacks were investigated. Sulfide may exert an inhibitory effect on dune slack plants, but several pioneer species exhibit ROL (Radial Oxygen Loss) and thereby protect themselves against free sulfide. Under oxic conditions free sulfide will be oxiginated to harmless sulfate. However, successive species when not capable of ROL may be sensitive to free sulfide and cannot invade the area. Therefore, the occurrence of free sulfide may have a stabilizing effect on the pioneer vegetation. Data on the vertical distribution of oxygen, redox and sulfide were collected in mesocosms with Littorella uniflora or Carex nigra, with and without microbial mats and compared to control mesocosms. Also, in situ data were collected in a dune slack on the Frisian Island of Texel. In the mesocosms, free sulfide was detected only at nighttime in C. nigra populated mesocosms and in unvegetated units, but not in L. uniflora vegetated mesocosms. In the field, sulfide and redox profiles showed distinct differences between the groundwater exfiltration and infiltration site of the dune slack. At the exfiltration site, sulfide was only occasionally found; in contrast, measurable amounts of free sulfide were regularly found at the infiltration site of the slack. Since Phragmites australis dominates in the infiltration site of the slack, the results suggest that free sulfide accelerate the succession, rather than slowing it down by the exclusion of some plant species.     

Permanent swamp vegetation of the Upper Nile

This paper describes vegetation in the nothern Sudd area of the Sudan. A visit by boat was made in April 1978 along the White Nile from Malakal to Lake No; to the inflow regions of the Bahr el Jebel, the Bahr el Zeraf and to the Bahr el Ghazal. Only the vegetation along the fringe of the rivers was observed as plants were tall and dense and it was not possible to penetrate into the inner swamps.The outer edge of the vegetation was fringed by extensive mats of free-floating Eichhornia crassipes which was easily dislodged and formed floating islands to be carried downstream. The main rivers, excluding the Bahr el Ghazal, were too deep and turbid to support beds of submerged species but plants such as Ceratophyllum demersum could be found amongst floating plants. Vossia cuspidata usually produced a broad zone to the landward of Eichhornia. It dominated the shallow water with a floating raft of stems growing out from the shore over the water surface. Massive stands of Cyperus papyrus and/or Phragmites karka, over 5 metres tall, dominated the vegetation behind and sometimes excluded the Vossia zone. The papyrus could form dense, floating rafts of rhizomes at the water's edge, but Phragmites always remained firmly rooted to the bottom. Floating papyrus and Vossia would become detached from the main beds and drifted downstream with Eichhornia.Creepers were common amongst papyrus but less common amongst Phragmites where the vegetation was generally more dense. Large stands of Typa domingensis were observed behind the fringe vegetation.The vegetation of the Bahr el Ghazal, in marked contrast to the rest, was stunted, and reasons for this are suggested. Species diversity was greater and the less turbid waters allowed considerable development of floating-leaved and submerged species.Estimates of fresh weights and heights of dominant vegetation types were attained but methods were very laborious and alternative ways have been suggested. The fresh weight of Eichhornia from a one metre square quadrat in the White Nile was around 70 kg. The shoots of Phragmites weighed 18.5 kg and Cyperus papyrus, 11.0 kg m^–2.     

Floating mats: their occurrence and influence on shoreline distribution of emergent vegetation

1. A study was conducted on the northern shore of Lake Victoria (Uganda) to determine the factors controlling the occurrence of floating root mats and the influence of the floating mats on the distribution of emergent vegetation. 2. Environmental conditions within 78 bays in the study area were characterised using bay size, wave exposure, water depth, littoral slope, sediment characteristics and water level fluctuations. Emergent plants that form floating root mats occur along the shores of these bays. The way in which commonly occurring shoreline vegetation was distributed across a wave‐exposure gradient was compared with their distribution across a water level fluctuation gradient. 3. Results suggested that wind–wave action and water level fluctuations are important factors determining the occurrence of floating mats. Mat‐forming plants occur in the most sheltered locations along the shore and in waterbodies with modest water level fluctuations. 4. The ability to form mats facilitated the lakeward expansion of emergent plants. Plants forming floating root mats had a larger depth range than non‐mat forming plants. 5. The initiation mechanisms for the floating mats of emergent vegetation in Lake Victoria appear to be: (i) invasion of mats of free‐floating plants by emergent vegetation; and (ii) detachment of emergent plants from the lake bed following flooding. 6. The formation of floating mats comes with a cost and benefit to emergent plants. The cost is increased vulnerability to damage by water level fluctuations or wind–wave action, leading to reduced horizontal distribution. The benefit is that deep flooding is avoided, thus increasing vertical distribution. The net effect may be to lead to dominance of mat‐forming plants in low‐energy environments and non‐mat‐forming plants in high‐energy environments.     

Effects of shallow flooding on vegetation and carbon pools in boreal peatlands

Question: What are the effects of shallow flooding on boreal peatlands on vegetation composition and size of carbon pools in the living and dead vegetation? Location: Lake 979, Experimental Lakes Area, northwestern Ontario, Canada. Methods: A boreal basin peatland complex with treed bog, open bog, and open water was experimentally flooded by raising water level ca. 1.3 m. Vegetation and above‐ground biomass were compared between pre‐flood conditions and those nine years after flooding. Peat accumulation since flooding was also quantified. Results: Flooding caused almost all trees to die, leading to a net loss of 86% of the above‐ground living plant biomass after nine years of the flooding. Floating up of peat was rapid in the central part of the basin, and the floating peat mats were characterized by newly established open bog community. Wetland types were diversified from bog into open bog, fen, and marsh, accompanied with great species turnover. Floating open bog community accumulated the greatest amount of peat since flooding. Conclusions: This study shows that shallow flooding of bog vegetation can lead to quick re‐establishment of open bog vegetation upon the floating up of peat mats as well as changes to more diverse vegetation over decadal time spans. We estimate that the carbon pools in 2002 in living and dead plant biomass since 1992 are comparable to what they were in the above‐ground biomass in 1992. Flooding caused an initial net decrease in carbon stores, but carbon in the pre‐flood living plant biomass was replaced by both carbon in dead biomass of the pre‐flood vegetation and newly sequestered carbon in new peat growth and post‐flood living plant biomass. Possible vegetation change toward bog‐dominated system could lead to increasing rate of new peat growth, which could affect future carbon sink/source strength of the system.     

Epiphyte associations and canopy soil volume: nutrient capital and factors influencing soil retention in the canopy

• Canopy soil (CS) volume reflect epiphyte community maturity, but little is known about the factors that retain CS or species succession within it. Humus fern species (e.g. Phlebodium areolatum) appear capable of retaining CS.
• In ten Quercus spp. we sampled 987 epiphyte mats to examine the role of the common epiphyte species and crown traits determining CS volume, in order to infer successional stages and identify pioneer and late successional species. Branch traits (height, diameter and slope), CS volume and cover of the epiphyte species were determined for each mat. Nutrient content was determined in CS random samples of 12 epiphyte associations and sizes (one sample from each size quintile).
• A total of 60% of the mats lack CS. Cover of P. areolatum was the main variable explaining CS volume, and this species was present in 46.8% of those with CS. Epiphyte composition was highly variable, but pioneer (species appearing in monospecific mats, without CS) and late successional species could be identified. Canopy soil nutrient content was similar among the associations of epiphytes. Magnesium, Ca and pH decreased with CS volume, while P and N increased.
• Phlebodium areolatum is associated with high CS volumes and could act as a key species in its retention. Monospecific mats of pioneer species lack CS or have low volumes, while CS is much higher in mats with late successional species, but the mechanisms of CS formation and nutrient retention in response to interactions between epiphyte species remain to be tested.

     

Vegetation development on extensive vegetated green roofs: Influence of substrate composition, establishment method and species mix

Technology for establishment of vegetated roofs (green roofs) has developed rapidly over recent years but knowledge about how these systems will develop over time is still limited. This study investigates vegetation development on unfertilised thin extensive vegetated roofs during a 3-year period. The vegetation systems investigated were designed to be low maintenance and had a saturated weight of 50 kg/m², a thickness of 4 cm and drought-resistant succulent and bryophyte vegetation.Vegetation development was investigated in relation to: establishment method, species mixture and substrate composition in a factorial experiment. Vegetation cover was investigated using point intercept.Moss was found to develop on most substrates and reached more than 80% cover on some plots. Sedum album and Sedum acre were the dominant species on the roofs. S. acre was found to decrease drastically after 2 years. The lack of difference found in this study between the establishment techniques shows that there are other possible marketable ways to construct vegetated roofs in Sweden, as an alternative to vegetation mats. Uniform extensive vegetated roofs with a high dominance of succulent species have limited value for plant biodiversity, as few species establish spontaneously.     

城市遗存山体植被群落特征对不同人为干扰方式及强度的响应

快速城市化发展对城市内植被和生物多样性产生了显著的影响,研究植物群落特征对人为干扰的响应规律可为城市残余生境生态恢复、生物多样性保护及植被的合理开发利用提供科学依据。以典型的喀斯特多山城市贵阳市为研究区域,城市遗存山体为研究对象,基于遥感解译与群落生态学调查和分析等方法,探讨了不同人为干扰方式及强度对城市遗存山体植被特征、群落物种组成和多样性的影响。结果表明：（1）中度人为干扰强度下城市遗存山体植被覆盖度（FVC）和植被净初级生产力（NPP）数值最高;复垦干扰下FVC和NPP值相一致且为最高,中小型公园化利用山体FVC和NPP值完全不一致且NPP最低。（2）不同人为干扰强度和方式下城市遗存山体间的平均物种数和生活型构成均存在显著性差异。整体上城市遗存山体的平均物种数在不同干扰强度下表现为轻度人为干扰 > 中度人为干扰 > 重度人为干扰;不同干扰方式下的平均物种数呈现为人为踩踏 > 构筑物 > 工程建设 > 公园化利用 > 复垦 > 工程开挖的趋势;重度干扰下城市遗存山体的落叶乔木、灌木占比最高,中度干扰下常绿灌木和多年生草本为主。（3）不同干扰强度下城市遗存山体植物群落垂直结构各层次物种多样性指数均偏低且存在显著性差异,乔木层、灌木层Shannon-Wiener （H''）、Simpson （D）、Margelf （R）指数在中度干扰强度最大,而在草本层均最小;均匀度Pielou （Jh）指数在乔木层和草本层中表现为轻度人为干扰 > 中度人为干扰 > 重度人为干扰,而在灌木层完全相反。（4）乔木层4种多样性指数在不同干扰方式下的差异较大;灌木层和草本层的多样性指数在人为踩踏和构筑物建设干扰方式下显著高于其它干扰方式,工程开挖为主的干扰方式下灌木层和草本层多样性各指数均偏低且存在显著性差异。总体而言,轻中度人为干扰对城市遗存山体植物群落物种组成和多样性的影响不突出,且中度干扰对植物群落物种多样性具有一定的促进作用,但重度干扰对城市遗存山体植物群落特征存在明显的负面影响。     

不同更新方式对林地植被生长及土壤性状的影响

本文研究天然次生林采伐迹地的三种更新方式对林地植被及土壤性状的影响。结果表明,炼山人工造林对林地植被和土壤有一定的破坏作用,是影响林木生长、导致物种丧失、引起林地水土流失和地力衰退的重要原因。不同林分物种丰富度为:天然更新 >人促更新 >炼山人工造林;林下植被生物量为:人促更新 >天然更新 >炼山人工造林。不炼山的天然更新和人促更新,有利于物种多样性保护、植被生长、林地土壤理化性状改善和土壤肥力提高,并具有更高的经济效益。     

Net woody vegetation increase confined to seasonally inundated lowlands in an Australian tropical savanna,Victoria River District,Northern Territory

Abstract Georeferenced digital aerial photographs were used to assess changes in overstorey vegetation cover since 1948 in the Victoria River District, Northern Territory, Australia, across a range of lowland tropical savanna habitats and with explicit consideration of known and variable site‐specific grazing and fire management histories. Vegetation surveys at corresponding locations on the ground identified five distinct woody vegetation communities defined primarily by water drainage and secondarily by soil characteristics. Air‐photo analyses revealed that, contrary to popular perceptions and in contrast to results from other habitats, there has been no generalized net increase in overstorey woody vegetation cover across the full range of lowland savanna habitats. Rather, different habitats exhibited distinctly different vegetation change mechanisms: low‐lying seasonally inundated ‘wet’ habitats have experienced woody vegetation increase since 1948, whereas well‐drained ‘dry’ habitats have experienced overstorey vegetation stability or loss. In almost every instance woody vegetation increase could be attributed to the invasion or proliferation of a single species, Melaleuca minutifolia F.Muell. The extent of M. minutifolia increase was unrelated to historical grazing/fire regime. Demographic analyses for this species revealed that recruitment was often episodic and that synchronized recruitment events occurred uniformly across the full range of historical management treatments, most likely as a consequence of favourable climatic conditions in years with an extended wet season. Heavy grazing facilitated juvenile survival and/or recruitment, most likely by reducing grassy fuel loads and eliminating landscape fire. We conclude that while there has been no generalized net increase in overstorey woody vegetation cover in lowland environments, savanna dynamics are complex, and multiple change mechanisms have occurred simultaneously in different habitats, some of which have been significantly transformed since 1948. Where net woody vegetation increase has occurred it is primarily a natural consequence of episodic M. minutifolia establishment in climatically favourable years, but the extent and magnitude of this effect is likely mediated by fire/grazing regime.     

Sampling plant functional traits: What proportion of the species need to be measured?

Question: Understanding functional change in vegetation and how it might impact on vegetation change and ecosystem function entails measuring plant traits and attributes in situ. However, it is not realistically possible to sample every species for every trait, hence we need to address the consequences of not sampling all species. Location: Nine arable and grassland sites from the machair of the Western Isles, UK and twenty grassland and woodland sites from Nynäs Nature Reserve, southern Sweden. Methods: The effects of progressively reducing the proportion of species used to estimate the weighted mean of a range of continuous and qualitative traits were assessed. Results: Relative abundance and species traits were related, and hence there is a cost in accuracy in reducing the number of species sampled in estimating the weighted mean for the vegetation. This cost was higher for qualitative traits than quantitative ones. Conclusion: The analysis suggested that for the quantitative traits a minimum of those species that make up at least 80% of the vegetation should be sampled if traits do not vary greatly between species. If this variability is high and the trait is likely to be correlated to abundance then greater effort in sampling species for traits is required. Qualitative information on the rarer species should still be entered into the analysis if it can be accessed in any way, even if quantitative information for that species is unavailable.     

半干旱黄土小流域不同恢复方式对生态系统多功能性的影响

在黄土高原大规模退耕还林（草）背景下,植被恢复对生态系统功能会产生极大影响。以往研究多为比较不同恢复方式或植被类型的单一生态系统功能,对生态系统多功能性的研究亟待加强。因此,基于甘肃定西龙滩流域3种恢复方式（天然荒草、自然恢复、人工恢复）6种植被类型（长芒草草地、赖草草地、苜蓿草地、柠条灌丛、油松林、山杏林）38个样地调查数据,选取与土壤养分储存与循环、水源涵养、初级生产力、多样性维持等相关的23个功能指标利用平均值法量化生态系统多功能性。研究结果显示,（1）除营养物转化与循环功能外,其余土壤相关的生态系统功能在不同恢复方式与植被类型间均具有显著性差异（P<0.05）。人工恢复植被的土壤肥力显著高于自然恢复植被;人工恢复植被中土壤肥力从高到低依次为柠条灌丛、苜蓿草地、山杏林、油松林。自然恢复植被的水源涵养功能显著高于人工恢复植被。（2）除植物生长策略外,其余植物相关的生态系统功能在不同恢复方式与植被类型间均具有显著性差异（P<0.05）。人工恢复植被中地上初级生产力从高到低依次为山杏林、油松林、柠条灌丛、苜蓿草地,并显著高于自然恢复植被。人工恢复植被中植物养分吸收能力从高到低依次为苜蓿草地、柠条灌丛、油松林、山杏林,并显著高于自然恢复植被。自然恢复植被的物种多样性显著高于人工恢复植被。（3）生态系统多功能性在不同恢复方式与植被类型间均具有显著性差异（P<0.05）。生态系统多功能性表现为人工恢复植被高于自然恢复植被,但人工恢复植被的水源涵养功能与物种多样性均低于自然恢复植被,不利于生态系统的可持续发展。研究认为,在植被恢复具体实践中,应针对不同的恢复目标,根据各植被类型的功能特征,制定因地制宜的植被恢复战略。     

Community structure and pigment organisation of cyanobacteria-dominated microbial mats in Antarctica

Benthic microbial mat communities were sampled from 20 lakes, ponds and streams of the McMurdo Sound region, Antarctica. At least five distinct assemblages could be differentiated by their cyanobacterial species composition, pigment content and vertical structure. The most widely occurring freshwater communities were dominated by thin-trichome (0·5–3 µm) oscillatoriacean species that formed benthic films up to several millimetres thick. ‘Lift-off mats’ produced mucilaginous mats 1–5 cm thick at the surface and edge of certain ponds. Another group of oscillatoriacean communities was characteristic of hypersaline pond environments; these communities were dominated by species with thicker trichomes such as Oscillatoria priestleyi. Black mucilaginous layers of Nostoc commune were widely distributed in aquatic and semi-aquatic habitats. Dark brown sheath pigmentation was also characteristic of less cohesive mats and crusts dominated by Pleurocapsa, Gloeocapsa and Calothrix. High performance liquid chromatography analysis of the lipophilic pigments showed that the upper region of most of the Antarctic mats was enriched in sheath pigments (scytonemin) and/or certain carotenoids such as myxoxanthophyll and canthaxanthin. Most of the chlorophyll a (Chla), as well as phycocyanin, β-carotene and echinenone, was located in the lower strata of the mat profiles. In many of these communities most of the photosynthetic biomass occurred in a ‘deep Chla maximum’ that was well protected from short-wavelength radiation by the surface layer of light-screening pigments.     

Disturbance of salt marsh vegetation by wrack mats in Great Sippewissett Marsh

To quantify disturbance to salt marsh vegetation, and to test the notion that disturbance and species richness are related, we studied disturbance of vegetation by 195 wrack mats that had become stranded over Great Sippewissett Marsh. The mats varied in area, thickness, residence time, and elevation of stranding. Mats that were large, that had residence times of 3–4 months, and were stranded at higher elevations produced the most damage, ranging from total eradication to a decrease in shoot density of underlying vegatation. Thickness had no effect. About 70% of mats caused no damage, and of those that did, damage was usually 50% or less of the area beneath the mat. Plant species were differentially distributed along the tidal excursion within the marsh, and there were more species (8–9) high in the intertidal range than lower (4–6 species). Vertical distribution of species, species richness, and rate of annual disturbance were not well correlated, although highest and lowest disturbance rates corresponded to highest and lowest species richness. Most of the increases in species richness, however, occurred over a very small range of disturbance, so narrow that it seemed unlikely that disturbance affected richness. It seems more likely that factors other than disturbance rate control vertical position of species in salt marshes. It also appears that the effect of disturbance by wrack is less important than has been claimed.     

Confocal Laser Scanning Microscopy Image Analysis for Cyanobacterial Biomass Determined at Microscale Level in Different Microbial Mats

We recently published a new method based on determining cyanobacterial biomass by confocal laser scanning microscopy image analysis (CLSM-IA) (Solé et al., Ultramicrosc 107:669–673, 2007). CLSM-IA allows biomass calculation for microorganisms of a small size, since the limit of the technique’s resolution is that generated by a voxel, the smallest unit of a three-dimensional digital image, equivalent to 1.183 × 10⁻³ mgC/cm³ of sediment. This method is especially suitable for the quantitative analysis of a large number of CLSM images generated from benthic sediments in which complex populations of cyanobacteria are abundant, such as microbial mats. In order to validate the new CLSM approach, mats with varying structural characteristics were studied. We have grouped them into three types: Microcoleus mats (laminated), sandy mats (nonlaminated and composed of well-sorted quartz sands), and oil-polluted mats. In this work, we applied CLSM-IA in natural [the Ebro delta and Sant Jordi colony (Spain), Salins-de-Giraud and Etang de Berre (France), and Orkney Islands (Scotland)] and artificial [mesocosms (Israel)] microbial mats. A total of 4,103 confocal images were obtained in order to determine total and individual cyanobacteria biomass profiles, at microscale level. The data presented in this paper show the efficacy of the method, as it can be applied to highly diverse mat samples.     

乌兰布和沙漠东北缘荒漠-绿洲过渡带植被地上生物量估算

干旱区荒漠植被地上生物量是植被生长状况评价与荒漠化监测的重要指标。在乌兰布和沙漠东北缘的荒漠-绿洲过渡带选取典型区,基于地面调查数据构建主要植物种的异速生长方程,对样方内的植被地上生物量进行估算;基于样方调查数据和Quick Bird影像数据,分别建立植被指数与人工固沙林和荒漠植被地上生物量的回归模型,并对研究区植被地上生物量进行估算。结果表明:植冠体积V是较好的预测变量,所得荒漠植物异速生长方程精度较高,能够满足样方内荒漠植被地上生物量估算需要;采用RVI对数模型估算人工固沙林地上生物量的效果最好(R~2=0.72,RMSEP=56.15),采用RVI线性模型估算荒漠植被地上生物量的效果最好(R~2=0.82,RMSEP=15.07);研究区内荒漠植被和人工固沙林的单位面积地上生物量分别为90.73g/m~2和105.28g/m~2。该研究可以为荒漠化监测和荒漠植被遥感信息提取提供参考。     

Propagule input,transport and deposition in riparian environments: the importance of connectivity for diversity

Question: How important is hydrochory for dispersing propagules along riverbanks and to what extent do the quantity and species composition of deposited propagules reflect the riparian vegetation, represent “new” species that are not present in the vegetation, and vary with river flow and season? Location: River Frome, Dorset, UK. Methods: Over 13 consecutive 6‐week time periods, during which river water levels were continuously monitored, aerial inputs of propagules to riverbanks were sampled using funnels, hydrochorous propagule transport was sampled using drift nets, and deposition across the riverbanks was sampled using astroturf mats. A survey of the riparian vegetation enabled comparison between samples and the standing vegetation, so that “new” species could be identified. Differences in propagule abundance and diversity between sampling methods, time periods and locations were tested using Mann‐Whitney U‐tests and Kruskall‐Wallis ANOVA. DCA established contrasts in the floristic composition of all deposited propagules and “new” propagules between different sample types, time periods and locations. Results: Aerial seed fall generated few propagules of low species richness. Hydrochory introduced large numbers of propagules and new species, resulting in high propagule deposition on the riverbank. The number and diversity of deposited propagules was governed by seasonal patterns of seed release and the hydrological regime. Propagule deposition was significantly greater on the most frequently inundated parts of the riverbank and autumn floods were particularly important for transporting “new” species to the study site and for remobilizing previously released propagules. Conclusions: The abundance and diversity of propagules deposited along riverbanks is dependent upon high river flows, which facilitates connectivity between the channel and the riparian zone.     

The urban matrix and artificial light restricts the nightly ranging behaviour of Gould's long‐eared bat (Nyctophilus gouldi)

Cities are heterogeneous landscapes, with remnant vegetation interspersed amongst areas designed for human use. Native wildlife remaining in urban areas are only likely to thrive and persist if they incorporate human altered areas into what they perceive as habitat. Many sensitive species may be lost if they are restricted to remnant vegetation, and cannot use the urban matrix. In this study, we quantify spatial aspects of the ranging behaviour of Gould's long‐eared bat (Nyctophilus gouldi) using radio‐telemetry and acoustic surveys to determine use of the suburban–bushland interface. This species represents a group prone to extinction due to biological attributes that adapt it to flight within cluttered vegetation, making it more specialized. We radio‐tracked 19 individuals in Cumberland State Forest (CSF), a 40‐ha remnant located in north‐west Sydney, New South Wales, Australia. The nightly range (95% Kernel Density Estimator) was small and localized, and was no greater than 80 ha, where individuals moved on average less than 300 m from roosts each night. All individual N. gouldi tracked used bushland in an almost obligate manner, where up to 100% of used habitat was within local bushland, with little to no use of areas classified as ‘urban’ (residential, commercial and educational land uses). Small open spaces exposed to artificial lighting within the main ranging area of CSF had significantly lower activity (bat passes) of Nyctophilus spp. and significantly higher activity of other species more tolerant of urbanization (P < 0.05). Our results demonstrate that artificial lighting can ‘spill‐over’ into bushland and alter the use of preferred habitat. We conclude that large patches (>40 ha) of protected remnant vegetation must be managed to reduce further degradation, and smaller isolated patches could be restored to provide habitat, particularly in narrow bushland corridors, to assist these species to tolerate urban areas.     

Secondary Succession and Natural Habitat Restoration in Abandoned Rice Fields of Central Korea

Floristic composition and soil characteristics (moisture, pH, nutrient contents) in abandoned upland rice paddies of different ages were analyzed to clarify the regenerative aspects of succession as a tool for habitat restoration. The study sites represented five seral stages: newly abandoned paddy fields; successional paddy fields abandoned for 3, 7, and 10 years; and a 50‐year‐old Alnus japonica forest. A vegetation sere was apparent in changes of dominant plant species in the order Alopecurus aequalis var. amurensis (annual grass), Aneilema keisak (annual forb), Juncus effusus var. decipiens (rush), Salix koriyanagi (willow), and Alnus japonica (alder) communities. These temporal stages resemble the spatial zonation of vegetation in local riparian floodplain ecosystems, indicating a hydrosere, with soil moisture decreasing over time. Age distributions and life forms of the dominant plant species support a “tolerance” model of secondary succession, in which the established species persist into later successional stages. Persistence of earlier colonizers led to a net cumulative increase in species richness and a more even distribution of species cover with increasing field age. Between 10 and 50 years, vegetation stabilizes as an alder community. Soil moisture content decreased steadily with paddy field age after an initial rise immediately after their abandonment, whereas pools of organic matter, N, P, K, Ca, and Mg, increased with field age. The pace and direction of recovery of native vegetation and natural soil properties in these abandoned rice paddies resembled classic old field succession, a form of secondary succession that often serves as a template for guiding restoration efforts. Active intervention, in particular dismantling artificial levees, could accelerate the recovery process, but natural habitat recovery generally appears sufficiently robust to achieve “passive” restoration of this rare community without intervention.