Coexistence of Juncus articulatus L. and Glyceria australis C. E. Hubb. in a temporary shallow wetland in Australia.

Juncus articulatus, a species introduced to Australia, is codominant over large areas of Mother of Ducks Lagoon but is rare in other lagoons. It occurs widely within the lagoon but is concentrated in lower, wetter areas that are more disturbed by birds and cattle. This suggests that J. articulatus may be separated over elevation (and therefore water regime) and disturbance gradients from the native grass Glyceria australis, the dominant species in the lagoon. This paper compares the growth and interaction of G. australis and J. articulatus under different water regimes. The species responded differently to water regime both in monoculture and in mixture. Above ground production of J. articulatus was greatest under fluctuating water levels, least under a damp water regime and intermediate under flooded conditions. G. australis production was greatest under the damp, least under the flooded and intermediate under the fluctuating water regime. The outcome of interaction is dependent on water regime and time. After one year J. articulatus was the superior competitor under all water regimes. At the end of two years J. articulatus was still the superior competitor under fluctuating and flooded water regimes but not under the damp regime. The change in outcome after two years was due to the competitive superiority of G. australis during the second year under all water regimes. The relative importance and the management implications for the invasive potential of J. articulatus are assessed in shallow Australian wetlands with fluctuating water regimes.     

Consequence of ramet defoliation on plant clonal propagation and biomass allocation: Example of five rhizomatous grassland species

We investigated the effects of ramet defoliation frequency on clonal propagation and the patterns of biomass production and allocation on five rhizomatous species (Carex divisa Hude., Eleocharis palustris L., Juncus articulatus L., Juncus gerardii Lois. and Elytrigia repens L.). Plants were grown during an 18-week experiment in greenhouse conditions. The above ground parts of ramets were clipped following three treatments: frequent (every 2 weeks), moderate (every 4 weeks) and unclipped (control). The growth of C. divisa, J. articulatus and E. repens was strongly affected by defoliation whereas E. palustris and J. gerardii maintained a similar performance when defoliated. The latter were able to compensate for the biomass loss even after six consecutive clippings. Defoliation frequency had a significant effect on total biomass production for C. divisa, J. articulatus and E. repens while J. gerardii and E. palustris maintained total biomass production. Most of the studied species showed a decrease in clonal traits when defoliated. Clipped plants displayed fewer and shorter rhizomes. Defoliation had a strong influence in biomass production with a decrease in rhizome mass in all clipped species. A greater allocation to aerial parts and a lower to rhizomes were also detected. Moderate defoliation entailed intermediate response in 1/3 of detected significant effects of defoliation on plant traits. Finally, in the experimental conditions, E. palustris and J. gerardii were the most tolerant species to defoliation, while J. articulatus was intermediate and C. divisa and E. repens had the lowest tolerance.     

Germination potential,growth patterns and reproductive effort of Juncus articulatus and Glyceria australis in temporary shallow wetlands in Australia

Juncus articulatus is an exotic aquatic species occuring over large areas of Mother of Ducks Lagoon, a shallow and temporary wetland in northern New South Wales, Australia. The other dominant perennial species at the site is the native Glyceria australis. Little is known of the ecology of either species or of the potential of J. articulatus to invade wetlands. The germination potential, growth patterns and reproductive effort of J. articulatus and G. australis were compared in response to water regime, grazing and competition. Both species have persistent seed banks from which only a small percentage of seeds germinate in repeated wetting events and from sediment stored dry. J. articulatus germinated in very high numbers from Mother of Ducks Lagoon sediment, but was rare in other lagoons in the region. G. australis germinated in comparatively lower numbers from Mother of Ducks Lagoon sediment and was rare in other lagoon sediments despite being present in the extant vegetation in several lagoons. The introduced J. articulatus has several life cycle characteristics that differ from G. australis, notably a high allocation of biomass to inflorescences under all water regimes. Clipping stimulated above ground vegetative and sexual reproduction for J. articulatus and high numbers of tillers facilitate the sexual reproductive effort. Because J. articulatus is ubiquitous in the region, our results suggest that management of this exotic species should be directed towards minimizing recruitment opportunities and that this could be achieved by increasing variation in water regimes in combination with reduced disturbance from grazing.     

Differential responses to salinity help explain the replacement of native Juncus kraussii by Typha orientalis in Western Australian salt marshes

The influence of salinity on Typha orientalis and Juncus kraussii was documented in experiments on germination of seeds and on growth of seedlings and adult, rhizome-bearing plants. Juncus was more salt-tolerant than Typha at all three life-history stages, but salt tolerance increased with plant age for both species. Although seeds of both species germinated at 0 and 5 ppt, the germination data overestimated salt tolerance for Typha. Only the newly emerged seedlings of Juncus were capable of growth after removal from the 5 ppt NaCl solution to fresh water. Typha seedlings that initiated growth at 0 ppt grew well at 5 ppt but not at 10 ppt, while Juncus seedlings were tolerant of 10 ppt. Although the 20 ppt treatment caused high mortality of Juncus seedlings, the 10 ppt treatment mainly reduced growth. Adult plants of Typha, which were collected from the field, survived the 20 ppt treatment, while adult Juncus survived the 40 ppt treatment. The presence of salt (10–40 ppt) shortened the growing season for adult, rhizome-bearing plants of both Juncus and Typha, with a lower maximum and earlier peak in total leaf length and maximum leaf number. Thus, the greater biomass in fresh water was achieved primarily through a longer growth period, rather than a greatly accelerated growth rate. Interactions between the two species were explored in mixed-species culture of both seedlings and adult rhizome-bearing plants. Interspecific interactions were present at low salinity, but results differed for seedlings and adult plants. Typha seedlings failed to outgrow Juncus seedlings (at 5 ppt) but adult plants of Typha outgrew Juncus (at 0 ppt). Relative yields (biomass in mixed/pure pots) for Juncus and Typha seedlings were 0.85 and 0.26 at 5 ppt. Relative yields of adult plants were 0.24 for Juncus and 1.20 for Typha at 0 ppt. For both seedlings and adults, the species that ultimately dominated the mixed-species pots produced just as much total biomass as in pure-species pots, even though initial planting density was half as high. Extrapolating findings to the field situation, it appears that Typha has a narrow regeneration niche. The indication is that Typha could invade Juncus stands only following salinity reduction (allowing seed germination and early seedling growth) and after disturbance disrupts the native vegetation. The combined conditions of prolonged low salinity and open habitat occur where street drains are cut through the salt marsh. The probability of Typha becoming established would be highest in such areas. vegetative expansion would follow with continued freshwater influx, as rhizome-bearing plants gain an interspecific advantage.     

三江平原七星河流域湿地植物多样性及影响因素

湿地植物多样性是生物多样性的重要组成部分,在维护湿地生态功能和湿地生态系统稳定性方面发挥着极其重要的作用。为研究七星河流域湿地植物的多样性,选择七星河流域的七星河国家级自然保护区和三环泡国家级自然保护区,分别于2016年和2017年,对该流域内湿地植物进行了实地植物样方调查,共计调查194个样方,利用TWINSPAN进行了样方群落划分,并采用广义线性模型分析了影响植物多样性的影响因素。结果表明七星河流域湿地植物共有532种,隶属于80科,212属,主要群落类型为湿苔草-隐果苔草群丛;狭叶甜茅群丛;萍蓬草-狐尾藻群丛;漂筏苔草群丛;小叶章-臌囊苔草群丛;甜茅-芦苇群丛;芦苇群丛;貉藻群丛等,狭叶甜茅群丛物种多样性较单一,芦苇群丛的物种多样性较丰富。广义线性模型分析结果得出物种多样性与植被密度密切相关,植被密度越大,物种的多样性越小。为七星河流域物种多样性研究提供了重要的基础数据。     

The effect of flooding on carbon and nutrient standing stocks of helophyte biomass in rewetted fens

Rewetting can strongly affect the matter balance of peatlands. Owing to evidence of increasing CH₄ emissions and P mobilisation after rewetting, the effects of peatland restoration on climate, eutrophication risks and related controversies are discussed. Our study focuses on the role of helophytes in the carbon and nutrient balance of rewetted fen grasslands of NE Germany. We hypothesise that the helophytes Carex riparia, Glyceria maxima, Phalaris arundinacea, Phragmites australis and Typha latifolia differ in biomass production and nutrient standing stock according to site conditions and harvest time. We analysed the helophyte biomass three times a year and continuously measured water levels and quality. Biomass production, nutrient standing stock and litter accumulation were highly species specific and depended on nutrient availability, mean water levels and harvesting time. We conclude that helophytes store considerable amounts of carbon and temporarily improve the water quality by withdrawing high amounts of nutrients from the top soil during the growing season, and by reducing nutrient discharges. Restoring peatlands as effective nutrient and carbon sinks in the landscape should favour highly productive potentially peat-forming helophytes as Phragmites australis by establishing adequate water levels. If nutrients are to be removed from the degraded peatland, then management can combine the restoration of helophyte stands by rewetting with harvesting measures.     

The influence of water level fluctuations on the growth of four emergent macrophyte species

The influence of the amplitude of cyclic water level fluctuations on the growth of four species of emergent macrophyte (Cyperus vaginatus, Phragmites australis, Triglochin procerum and Typha domingensis) was studied in a controlled, pond-based experiment. The amplitudes of water level fluctuations were static, ±15, ±30 and ±45 cm, each cycling over a forty-day period. In all treatments the water level fluctuated around an initial water depth of 60 cm. Within each amplitude treatment, plants were grown at three elevations with the sediment surface at 20, 40 or 60 cm. Only T. domingensis and P. australis showed a significant response to amplitude. Biomass of T. domingensis was similar in the static, ±15 and ±30 cm amplitude treatments but dropped by ca. 52% when grown in amplitudes of ±45 cm. In contrast, the largest biomass for P. australis occurred in the ±30 cm amplitude treatment suggesting this species prefers moderately fluctuating water levels. The response of P. australis to amplitude was contingent upon elevation with plants growing in the ±45 cm amplitude, low elevation treatment having particularly low biomasses. C. vaginatus biomass increased with increasing elevation but did not respond to amplitude while T. procerum did not respond to either amplitude or elevation likely due to the ability of the species to photosynthesise under water. The relative growth rate and the average emergent surface area were logarithmically related in C. vaginatus suggesting flooding of the photosynthetic canopy was limiting the ability of this species to acquire atmospheric carbon. No clear relationship was found for T. domingensis or P. australis indicating that a factor other than access to atmospheric carbon was restricting the growth of these species.     

Reproductive allocation,seed dispersal and germination of <Emphasis Type="Italic">Myricaria laxiflora</Emphasis>, an endangered species in the Three Gorges Reservoir area

Myricaria laxiflora is an endangered plant that grows in the flood zone along the Yangtze River in the Three Gorges area from 70 m to 155 m above sea level. To understand the spatial distribution patterns of the species and to provide information for developing conservation strategies, we used field surveys to study its seed reproduction and dispersion, and used growth chambers to study seed germination. Results showed that M. laxiflora produced many flowering branches, inflorescences and seeds. Seeds were very small and output was high although biomass allocation to reproduction was low (∼4%). Reproductive allocation was strongly correlated with the biomass of stems and leaves. Seeds were dispersed either by the wind or the river current. Wind-dispersed seeds usually settled within 25 m from parent plants leading to a clumped distribution of individuals in populations. Water-dispersed seeds often landed and established on strands of firth where the fine sediment and gentle sloping were available. Seedlings that emerged from water-dispersed seeds were distributed along the water flood line. The life-span of M. laxiflora seeds was about 7 days. Seeds could germinate within 24 h when they absorbed adequate amounts of water. Soil water content was a key factor limiting the establishment ability of M. laxiflora. Experiments showed that the minimum soil water content for germination to occur was 10% on sand or 17% on sandy soil substrates, and the optimal conditions were on saturated soils. The water content of sandy soils on the riverbank was lower than 10% in autumn, the dry season, and seeds were able to germinate only on sandy beaches that were intermittently inundated by the fluctuating river current. These characteristics of seed dispersal and germination limit the ability for M. laxiflora to expand its distribution. These results provide information essential for the conservation and reintroduction of this endangered species.     

How do depth,duration and frequency of flooding influence the establishment of wetland plant communities?

In many temporary wetlands such as those on the Northern Tablelands of New South Wales Australia, the development of plant communities is largely the result of germination and establishment from a long-lived, dormant seed bank, and vegetative propagules that survive drought. In these wetlands the pattern of plant zonation can differ from year to year and season to season, and depth is not always a good indicator of the plant community composition in different zones. In order to determine which aspects of water regime (depth, duration or frequency of flooding) were important in the development of plant communities an experiment using seed bank material from two wetlands was undertaken over a 16 week period in late spring–early summer 1995–1996. Seed bank samples were exposed to 17 different water-level treatments with different depths, durations and frequencies of flooding. Species richness and biomass of the communities that established from the seed bank were assessed at the end of the experiment and the data were examined to determine which aspects of water regime were important in the development of the different communities. It was found that depth, duration and frequency of inundation influenced plant community composition, but depth was least important, and also that the duration of individual flooding events was important in segregating the plant communities. Species were grouped according to their ability to tolerate or respond to fluctuations in flooding and drying. The highest biomass and species richness developed in pots that were never flooded. Least biomass and species richness developed in pots that were continuously flooded. Short frequent floods promoted high species richness and biomass especially of Amphibious fluctuation-tolerator species and Amphibious fluctuation-responder species that have heterophylly. Terrestrial species were able to establish during dry phases between short floods. Depth was important in determining whether Amphibious fluctuation-tolerator or Amphibious fluctuation-responder species had greater biomass. Longer durations of flooding lowered species richness and the biomass of terrestrial species. Experiments of this kind can assist in predicting vegetation response to water-level variation in natural and modified wetlands.     

The role of water level and salinity in the regulation of Juncus gerardi populations in former ricefields in southern France

Abstract. In the Rhône delta (southern France) Juncus gerardi is a dominant, strongly aggregating species in artificially flooded former rice fields. In order to explain this pattern, the effects of water depth, salinity and their interaction were measured on (1) seed germination and seedling development and (2) vegetative growth of J. gerardi in a controlled-environment experiment. The germination pattern of J. gerardi was affected by salinity. Low salinity (2 g/l NaCl) delayed germination while moderate salinity (12 g/l NaCl) reduced germination rate. In contrast, the germination of J. gerardi was not affected in the range of water depths tested (i.e. 0–10cm). Salinity negatively affected the development of below-ground parts, shoots and inflorescences. This negative effect of salinity on the vegetative growth of J. gerardi was amplified when combined with flooding. Flooding with fresh water (0–20 cm depth) did not limit biomass production during the experiment. However, a decrease in the ratio of below-ground/above-ground dry weight at deeper water depths suggests a limitation of the vegetative propagation of J. gerardi under prolonged flooding conditions. This hypothesis is supported by the negative correlation between the cover of J. gerardi and water depth found in an abandoned rice field. The limitation on seedling recruitment imposed by salinity and the depression of vegetative growth of J. gerardi due to a combination of salinity and water depth could explain the aggregate distribution of J. gerardi in former rice fields.     

Effect of soil moisture and sowing density on population growth ofEupatorium adenophorum andE. riparium

Summary Efect of sowing density on germination, establishment and growth of two perennial weeds,Eupatorium adenophorum spreng. andE. riparium Regel, was studied by sowing varying number of seeds of each species in pots. At high sowing density, seedling emergence did not proportionately increase with seed input. The yield and seed output per unit area was independent of sowing density. Survival of established plants was independent of soil moisture stress. The dry matter yield of both species declined at low moisture regime, the reduction being more inE. riparium. E. adenophorum produced more seeds at low moisture level, whileE. riparium at high moisture level. The resource allocation to roots was reduced due to moisture stress, especially inE. andenophorum.     

Reproductive efficiency and growth of Emex australis in relation to stress

The reaction of Emex australis to different degrees of stress was examined in a pot experiment by varying pot size and in a field experiment by varying density. In pots, the proportion of energy in seeds was more stable to the imposition of stress than in roots and stems; that in roots increasing with increasing stress and that in stems declining. Similarly in the field, there was little difference between densities of 1–32 plants m^?2 in the proportion of seeds in biomass. There were no significant differences in mean individual seed weights in either experiment and all plants set seed. Again in both experiments, high stress plants were more precocious than low stress ones. In pots, this took the form of earlier attainment of maxima in calorific values, ‘reproductive effort’, root, stem and seed weights and in the field, a shorter life cycle and earlier senescence. In pots, estimates of the overall mean reproductive effort were 62% for the low and medium stress plants and 36% for the high stress plants. The results are discussed in terms of the high values for reproductive effort, the plasticity and precocity of E. australis under stress and the implications for weed control.     

The influence of soil moisture on losses of buried seeds to fungi

Although soil fungi are likely to be a major cause of mortality for buried seeds, few ecological studies have examined the role these pathogens play in natural systems. In particular, few studies have investigated whether losses of seeds to soil fungi are habitat-dependent. We used fungicide treatments to investigate whether losses of buried seeds of four grasses (Bromus inermis, Danthonia spicata, Glyceria striata, and Poa pratensis) to soil fungi differed among meadows differing in soil moisture. We also applied water to some treatments, to determine whether this increased losses of seeds to fungi. For all four grasses, fungicide additions improved one or more measures of seed viability, though this effect was small. For Danthonia and Glyceria, fungicide was less likely to improve viability in dry meadows than in wet and/or mesic meadows. Adding water reduced some measures of viability of seeds of Danthonia and Poa in dry meadows, but fungicide partly counteracted these negative effects, suggesting that adding water reduced performance by increasing fungal attack. These results indicate that fungi represent a hazard for buried seeds of these species, particularly in wetter soils, and potentially may contribute to the reduction of populations of vulnerable species in wetter sites.     

Oviposition in Culicoides impunctatus under laboratory conditions

We present a laboratory-based examination of oviposition preference in the Scottish biting midge, Culicoides impunctatus (Diptera: Ceratopogonidae). A variety of oviposition substrates were screened in no-choice and choice bioassays for efficacy in eliciting an egg-laying response. Both upper-layer photosynthetic Sphagnum spp. moss and Juncus articulatus infusions were identified as producing increased oviposition under no-choice conditions. During choice trials against a control of damp cottonwool, upper-layer Sphagnum spp. moss produced a significantly greater egg-laying response. These conclusions are interpreted in terms of possible cues involved in oviposition site selection and assessed for future use in colonisation of this troublesome species.     

The impact of flooding and drought on seeds of Cnidium dubium, Gratiola officinalis, and Juncus atratus, three endangered perennial river corridor plants of Central European lowlands

The effects of flooding and drought on the post-flooding survival and germinability of seeds in the soil were investigated for three endangered river corridor angiosperms Cnidium dubium (Schkuhr) Thell., Gratiola officinalis L. and Juncus atratus Krocker. Freshly matured seeds were placed in small nylon bags and were buried in pots filled with soil collected from a wetland along the Lower Havel River. The pots were subjected to different winter/spring flooding treatments (30, 60, 120, and 180 days) and to drought for up to 3 years. Every year in spring, after drawdown, the seeds were exhumed, counted and tested for germination. Seed mortality of flooded seeds was low, except for C. dubium. Flooding did not affect germination of seeds of J. atratus. Flooding of seeds of C. dubium and G. officinalis had inconsistent, but no beneficial effects on germination of either. The year of harvest and the interannual variability of weather are found to be the main factors affecting germinability of C. dubium and G. officinalis in the course of the three consecutive years.The experiment showed that the capacity of the flooded seed bank to maintain germination ability and viability for extended periods of time could be directly related to the flooding duration of natural habitats of the three species. The three species are resilient to variable flooding. Seeds appeared desiccation tolerant, and single flooding events do not deplete their seed bank.     

Effects of an organic sediment on performance of young Phragmites australis clones at different water depth treatments

Performance of young Phragmites australis plants was examined after 7 weeks on an artificial nutrient-enriched inorganic substrate and on the same substrate to which an organic sediment from a eutrophic lake was added, at three different water depth treatments. Growth decreased, and proportional allocation of biomass to roots increased, with the addition of sediment. These differences were significant in shallow and deep water, but not at a medium depth. Concentrations of phosphorus and nitrogen in plant biomass decreased, and concentration of iron increased, with addition of sediment.The effects of sediment addition may have resulted from a decreased availability of nutrients in the substrate or from an impaired root functioning. Nutrient exhaustion in the substrate, due to a fast plant growth, can explain the relatively strong effects in shallow water. Deep water, on the other hand, probably restricted oxygen transport to the roots, resulting in an impaired root functioning in the low-redox sediment environment. The results show that, especially in relatively deep water, growth of undisturbed plants of P. australis may be inhibited by eutrophication of sediments, probably because of an impaired root functioning in sediments containing reduced toxic compounds (e.g. ferrous iron).     

EFFECTS OF WATER DEPTH ON TYPHA LATIFOLIA AND TYPHA DOMINGENSIS

The two species of Typha common in the southeastern United States, T. latifolia and T. domingensis differ substantially in their tolerance to deep water. The objective of this study was to examine the morphology and biomass allocation of these two species to determine if they have similar phenotypic responses to water depth. Replicate monocultures of the two species were established at a range of water depths in an artificial pond and allowed to grow for three growing seasons. At the end of the experiment, subsamples were harvested for determination of plant morphology as well as above- and belowground biomass. Both species of Typha showed increases in maximum height with increasing depth. The species less tolerant to deep water (T. latifolia) allocated more of its biomass to leaves with increasing water depth. In contrast, the deep water species (T. domingensis) showed increased total size of each ramet but a fixed percentage of biomass in leaves with increasing water depth. Both species had a decreasing incidence of flowering and decreasing shoot density with increasing water depth. In general, these species conform to expectations based on considerations of how their carbon budgets would be affected by water depth.     

Growth rates of selected Australian tropical rainforest tree species under controlled conditions

Controlled environment treatments were applied to assess the effects of temperature on the seedling mortality and growth rates of Toona australis and Flindersia brayleyana, two tropical rainforest tree species from northeast Queensland, Australia. Past workers have assigned these two species to the same ecological niche in terms of their response to canopy disturbance and gap-phase regeneration; however, their geographic ranges are very different. The hypothesis was that the species confined to the warm tropics (F. brayleyana) would have higher seedling mortality and a slower growth rate at lower temperatures than the species that occurs over a wide latitudinal range from the warm tropics to cooler temperate environments (T. australis). Significant differences were found in the growth rates of these two species in the warm (29/22° C) and cool (22/10°C), but not the intermediate (24/16° C), day/night temperature regimes. Their growth rates both decreased with decreasing temperature, but the decrease was significantly less for F. brayleyana which had the faster growth rate and lower seedling mortality in the cool regime. These results led to the rejection of the hypothesis and a test of the assignment of these two species to the same ecological niche. The test involved monitoring their growth to sapling-size in the intermediate temperature regime together with four other co-occurring tropical rainforest tree species belonging to different ecological niches. The growth rates and proportions of above-ground biomass allocated to woody tissue distinguished T. australis and a fast-growing pioneer species from F. brayleyana and three primary forest species. The stem heights and aboveground biomass of T. australis and the pioneer species exceeded the other four species by factors ranging from two to five. It is concluded that T. australis does not belong to the same ecological niche as F. brayleyana, and it is recommended that more research be conducted on the ecotypic temperature responses of the taxon T. australis.     

Reproductive strategies may explain plant tolerance to inundation: A mesocosm experiment using six marsh species

We investigated the impact of inundation duration on sexual and asexual reproduction strategies in six hygrophilic angiosperm species (2 annuals - Ranunculus sardous and Ranunculus ophioglossifolius, 2 rhizomatous - Juncus articulatus and Eleocharis palustris, and 2 stoloniferous species - Glyceria fluitans and Agrostis stolonifera). Plant growth during three inundation durations (natural, +3 weeks, +6 weeks) was assessed in 20 mesocosms. Biomass and reproductive traits were measured at the onset of flowering and at seed set.The six species maintained or increased their total mass in response to increased inundation period, suggesting a good tolerance to inundation stress. No changes were recorded in flowering time for the five species that flowered. The two annual species increased the number of flowers and mass allocated to sexual reproduction with increased duration of inundation, promoting extensive seed production. The response was species-specific in perennial species with an either a positive or a negative Gaussian curve of both traits in response to the increased duration of inundation. The duration of inundation affected ramet production in all perennial species except A. stolonifera, promoting ramet production in two out of the three species. In all species except E. palustris, the length and number of stolons or rhizomes were maintained, suggesting the importance of these connections in the resistance of perennial plants to flooding stress. These species occurring in repeatedly inundated habitats thus appeared to be tolerant to long inundations thanks to both sexual reproduction and vegetative propagation.     

Environmental changes affect ecosystem services of the intermittent Lake Cerknica

Lake Cerknica is an intermittent wetland with seasonal water level fluctuations. This paper discusses the possible changes of ecosystem services due to altered ecosystem functions caused by regional climate change. For this purpose, the lake's water regime was analysed and biomass production of common reed (Phragmites australis), the prevailing species, was related to ambient temperatures and water level. The effect of the latter was also examined for reed transpiration rate and plant diversity. The results revealed a gradual loss of seasonality of floods and droughts. High water level in winter months and temperatures at the beginning as well as the end of vegetation period were found to have a significant influence on reed biomass. The plant diversity research in six subsequent years in three different aquatic habitats revealed trends of a decrease due to increased water depth during the vegetation period. The complexity of the system and consequently ecosystem services might also be affected due to changes of other processes, which revealed to be related to water level; namely transpiration rate, plant mycorrhizal colonisation and soil mineralisation.