Effects of temperature and N:P ratio on the invasion success of the cyanobacterium Raphidiopsis raciborskii

Research that connects the effects of urbanization on biodiversity and ecosystem services is lacking. Ants perform multifarious ecological functions that stabilize ecosystems and contribute to a number of ecosystem services. We studied responses of ant communities to urbanization in the Lake Tahoe basin by sampling sites along a gradient of urban land development. We sampled ant communities, measured vegetation characteristics, quantified human activities, and evaluated ant-community responses by grouping ants into service-providing units (SPUs), defined as a group of organisms and their populations that perform specific ecosystem services, to provide an understanding of urbanization impacts on biodiversity and their delivery of ecosystem services. Species richness and abundance peaked at intermediate levels of urban development, as did the richness of 3 types of ant SPUs (aerators, decomposers, and compilers). With increasing land development aerator and decomposer ants significantly declined in abundance, whereas compiler ants significantly increased in abundance. Competing models demonstrated that precipitation was frequently among the strongest influences on ant community structure; however, urban development and human activities also had a strong, negative influence on ants, appearing in most models with DeltaAIC(c) < 2 for species richness and abundance patterns of SPUs and generalists. Response diversity was observed within SPUs, which suggests that the corresponding ecosystem services were maintained until development reached 30-40%. Our data provide evidence that ecosystem functions, such as water infiltration and soil productivity, may be diminished at sites subject to greater levels of urbanization and that conserving ant communities and the ecosystem services they provide could be an important target in land-use planning and conservation efforts.

Ecosystem-based management requires the promotion and integration of locally relevant ecosystem services. This needs an understanding of which ecosystem services local people value and how local valuation varies with socio-cultural and market factors. We convened ten focus group discussions and performed 105 household surveys from major indigenous groups and recent settlers about local values of various forest-based ecosystem services in changing landscapes of southwest Ethiopia. We found that the extent of ecosystem service use and assessment depends on socio-cultural background and gender of the informants, as well as income and cultural contributions of these services. Ecosystem service values vary in space and time where local people reported that they increasingly value services as they become scarce or in response to increased demands due to emerging markets or changes in production systems. Local people mostly appreciated a few services of high market value while most ecosystem services are not traded in local markets and hence not highly valued. Some low-rated ecosystem services such as fodder and medicinal plants were nonetheless widely used demonstrating the need to also conserve low rated ecosystem services that are used universally. We suggest promoting socio-cultural and other non-marketable ecosystem services to reduce the over-exploitation or exclusion of specific biodiversity components in conservation activities.

As a result of our study, data were obtained on the structure of the epilithon and the physicochemical parameters of the waters in the Chusovaya river near the town of Chusovoy for 2017–2018. The taxonomic structure, quantitative characteristics, dominant species, features of the distribution of the main groups of algae were studied. The algal flora includes 191 infrageneric algal taxa (168 species) from 6 divisions, 10 classes, 24 orders, 51 families and 86 genera. The taxonomic spectrum is based on diatoms (67.5% of the total numbers), green algae (21%), and cyanobacteria (9%). In the environmental and geographical aspects, the epilithon is mainly represented by widespread salinityindifferent benthic and plankton-benthic species, having an optimum in slightly alkaline or neutral waters. The epiliton of the Chusovaya river has reached a fairly high level of development. The values of the total biomass varied from 1.46 to 46.32 g/m2, and the abundance did from 1.5 to 31.7 billion cells/m2. The species diversity index (an average of 3.22±0.18) indicates species-rich and balanced algocenoses of the Chusovaya river, while in summer the indices are 1.9–2.2 times lower than in autumn. The dominant algae species differed in seasons, they were represented by diatoms or cyanobacteria in terms of their number, and by diatoms in terms of their biomass. In water samples with epilithon flushing, higher concentrations of chemical substances (NH4+, NO3-, PO43-, and Fetot) were noted than in river water, indicating the ability of the epilithon to accumulate substances. Significant changes in the biomass and/or abundance of epilithon as a function of the content of chemical substances in water and fouling washes were revealed. By the value of the saprobity index (from 1.34 to 2.27), the sanitary-biological state of the water in the Chusovaya river is assessed as satisfactorily pure (II–III water quality classes), the saprobity zone is ο-β-, β-mesosaprobic.

Mitten crab aquaculture is prevalent in China, however, knowledge about the threat of cyanobacteria in mitten crab aquaculture-impacted water bodies is limited. Here, seasonal variations of cyanobacteria and their relationships with environmental factors were investigated for Lake Guchenghu area. Results suggested the changes of cyanobacteria community in crab ponds distinguished from the adjacent lake. In the lake, cyanobacterial biomass (3.86 mg/L, 34.6% of the total phytoplankton) was the highest in autumn with the dominance of Oscillatoria, Aphanocapsa and Pesudanabaena. By contrast, in crab ponds, cyanobacteria (46.80 mg/L, 97.2% of the total phytoplankton biomass) were the most abundant in summer when Pesudanabaena and Raphidiopsis were the dominant species. Of particular note was that obviously higher abundance of filamentous and potentially harmful species (e.g., Raphidiopsis raciborskii and Dolichospermum circinale) were observed in ponds compared to the lake. Specifically, water depth (WD), permanganate index (CODMn), total phosphorus (TP), N:P ratio, and NO 2 −-N were the key environmental variables affected cyanobacteria composition. For crab ponds, N:P ratio, water temperature (WT) and TP were the potential environmental drivers of cyanobacteria development. This study highlighted the fact that mitten crab culture had non-negligible influences on the cyanobacteria community and additional attention should be paid to the cyanobacteria dynamics in mitten crab culture-impacted water bodies, especially for those potentially harmful species.

Toxic and non-toxic strains of Raphidiopsis raciborskii coexist widely in natural water bodies, with the dominance of toxic strains directly influencing bloom toxicity. This study investigates how temperature affects the relative dominance of toxic R. raciborskii strains and the production of cylindrospermopsin (CYN). We conducted monoculture and co-culture experiments in nutrient-rich BG11 medium at three temperatures (16 °C, 24 °C, and 32 °C) using two pairs of strains (CS506/CS510 from Australia and QDH7/N8 from China). The results revealed that the Australian strains failed to grow at 16 °C, while the Chinese strains thrived. In a co-culture experiment, the Australian toxic strain CS506 exhibited the fastest growth at 24 °C, whereas the Chinese toxic strain QDH7 reached similar maximum cell densities across all temperatures but peaked more quickly at 24 °C and 32 °C compared to 16 °C. Regardless of temperature and strain pairs, toxic strains consistently maintained a higher relative abundance than their non-toxic counterparts. Analysis using the rate of competitive displacement (RCD) model indicated that higher temperatures accelerated the displacement of non-toxic strains by toxic ones. Total CYN concentrations in co-cultures increased with temperature, although the cell quota of CYN (QCYN) did not vary significantly across temperatures. In co-culture, the CYN production rate during the exponential phase was positively correlated with cell growth rate, but this correlation weakened or reversed in the stationary phase, likely due to changes in nutrient availability. These findings suggest that rising temperatures under eutrophic conditions may enhance the growth and competitive advantage of toxic R. raciborskii strains, thereby exacerbating bloom toxicity.

The impact of solar cycles on forest stands, while important in the development of the forest environment during climate change, has not yet been sufficiently researched. This work evaluates the radial growth of European beech (Fagus sylvatica L.) in the mountain areas of southern Italy and central Europe (Czech Republic, Poland) in correlation to solar cycles (sunspot number), extreme climatic events, air temperatures and precipitation totals. This research is focused on the evaluation of the radial growth of beech (140 dendrochronological samples with 90–247 years of age) from 1900 to 2019. The time span was divided into the following three periods: (1) a period of regular harvesting (1900–1969), (2) a period of air pollution crisis (1970–1985) and (3) a period of forest protection (1986–2019). The results indicate that the solar cycle was significantly involved in radial growth on all research plots. With regard to the evaluated precipitation totals, seasonal temperatures and the sunspot number, the latter was the most significant. Temperatures had a positive effect and precipitation had a negative effect on the radial increment of beech in central Europe, while in southern Italy, the effect of temperature and precipitation on the increment is reversed. In general, the limiting factor for beech growth is the lack of precipitation during the vegetation season. The number of negative pointer years (NPY) with an extremely low increment rose in relation to the decreasing southward latitude and the increasing influence of climate change over time, while a higher number of NPY was found in nutrient-richer habitats compared to nutrient-poorer ones. Precipitation and temperature were also reflected in the cyclical radial growth of European beech. The relationship between solar cycles and the tree ring increment was reversed in southern Italy and central Europe in the second and third (1970–2019) time periods. In the first time period (1900–1969), there was a positive relationship of the increment to solar cycles on all research plots. In the tree rings of European beech from southern Italy and central Europe, a relationship to the 11-year solar cycle has been documented. This study will attempt to describe the differences in beech growth within Europe, and also to educate forest managers about the relevant influence of solar cycles. Solar activity can play an important role in the growth of European beech in central and southern Europe, especially during the recent years of global climate change.

Policies and research increasingly focus on the protection of ecosystem services (ESs) through priority-area conservation. Priority areas for ESs should be identified based on ES capacity and ES demand and account for the connections between areas of ES capacity and demand (flow) resulting in areas of unique demand-supply connections (flow zones). We tested ways to account for ES demand and flow zones to identify priority areas in the European Union. We mapped the capacity and demand of a global (carbon sequestration), a regional (flood regulation), and 3 local ESs (air quality, pollination, and urban leisure). We used Zonation software to identify priority areas for ESs based on 6 tests: with and without accounting for ES demand and 4 tests that accounted for the effect of ES flow zone. There was only 37.1% overlap between the 25% of priority areas that encompassed the most ESs with and without accounting for ES demand. The level of ESs maintained in the priority areas increased from 23.2% to 57.9% after accounting for ES demand, especially for ESs with a small flow zone. Accounting for flow zone had a small effect on the location of priority areas and level of ESs maintained but resulted in fewer flow zones without ES maintained relative to ignoring flow zones. Accounting for demand and flow zones enhanced representation and distribution of ESs with local to regional flow zones without large trade-offs relative to the global ES. We found that ignoring ES demand led to the identification of priority areas in remote regions where benefits from ES capacity to society were small. Incorporating ESs in conservation planning should therefore always account for ES demand to identify an effective priority network for ESs.

Mapping ecosystem services: The supply and demand of flood regulation services in Europe

气候变化已对物种分布范围和丰富度产生了极大的影响。荒漠生态系统对气候变化的反应可能更加敏感。作为荒漠生态系统的重要组成者,了解荒漠啮齿动物特别是优势鼠种将对气候变化如何响应,对于荒漠地区生物多样性的维持将具有重要意义。2002-2010年,采用标志重捕法对阿拉善荒漠4种不同生境下啮齿动物优势种群进行了研究,分别利用Spearman相关分析以及典范对应分析(Canonical Correspondence analysis,CCA)对啮齿动物优势种群动态与年平均温度和年降水量的相关性进行了分析。结果表明,不同啮齿动物优势种对温度和降雨的响应不同,尤其以子午沙鼠表现最为显著。跳鼠对温度的适宜性要高于仓鼠科的子午沙鼠和黑线仓鼠,而仓鼠科啮齿动物对降雨的适宜性高于跳鼠。较小尺度上的人为干扰更可能从改变食性和生境的途径上加剧或缓冲降雨对荒漠啮齿动物优势种的影响,而不是改变温度对啮齿动物的作用。

Phytoplankton community composition of Saginaw Bay, Lake Huron, during the zebra mussel ( Dreissena polymorpha) invasion: A multivariate analysis

Phytoplankton is a vital and important organism as a producer of the primary food supply of the marine and freshwater food webs. This study is conducted to investigate the variability of phytoplankton abundance related to environmental variables in the Terengganu River Estuary, by using statistical analysis. Total of ten water samples were collected, of which three stations were in the estuary and seven stations were in the coastal water. A total of 124 taxa of 55 genera, belonging to six taxonomic classes were observed at the study area. The order of phytoplankton abundance was diatoms > blue-green algae > golden-brown algae > dinofalgellates > green algae > euglenoids. The phytoplankton abundance was higher in the coastal area compared to the estuary, with the maximum density 764.10 cells mL-1 and 157.40 cells mL-1 respectively. It was recorded that 10.96% of the total abundance from the data collection was registered in the estuary, while the remaining 89.04% were logged in the coastal region. The freshwater phytoplankton was dominated by golden-brown algae (Chrysophyceae), while marine phytoplankton was governed by diatoms and blue-green algae. It was observed that the water temperature and salinity were positively correlated with marine phytoplankton but negatively related to freshwater phytoplankton. High levels of water temperature and hypersalinity at the coastal region was observed to enhance the production rate in the coastal region. In contrast, the nutrients were positively related to freshwater phytoplankton, but negatively correlated to the marine phytoplankton, which results in low concentrations of nutrients in the coastal region that could be caused by intensive uptake by the abundance of marine phytoplankton. This study revealed that environmental variables are an important element in determining the phytoplankton community compositions in the tropical region.

Sasi is one of the local wisdom from Maluku as a form of prohibition for the community in taking natural products based on a certain time that has been determined by the authorized customary institution in an area. However, local wisdom is often ignored and considered outdated in the development of environmental conservation programs. Whereas in practice, armed with local knowledge capital such as biological and ecological knowledge, indigenous people have been able to successfully protect potential ecological processes and regenerate various varieties of plants and animals that are sasi. In addition, Sasi implementation activities can also have an impact on local ecosystem services so that the sustainability of local communities can take place economically, socially, culturally, and ecologically. The purpose of this research is to find out the implementation activities of Sasi and the ecosystem services that are produced sustainably for the people of Maluku. The method used in this research is a systematic literature review. The results of this study show that Sasi implementation activities have a positive impact on ecosystem services in an area.

Metrics for a nature-positive world: A multiscale approach for absolute environmental sustainability assessment

Microcystis aeruginosa is the dominant alga forming cyanobacteria blooms, the growth of which is limited by available nutrients. Thus, it is necessary to study cyanobacteria blooms and explore the growth of Microcystis aeruginosa under different nutrient conditions. In this paper, we take Microcystis aeruginosa, including toxic Freshwater Algae Culture of Hydrobiology Collection (FACHB)-905 and non-toxic FACHB-469 strains, into account. The strains were cultured using a simulation device under different nutrient conditions. Ultraviolet spectra, three-dimensional fluorescence spectra, and kinetic parameter indicators of the two species are studied. Compared to FACHB-469, the results show that the specific growth rate of FACHB-905 is much higher, in particular, FACHB-905 is the dominant species under low nutrient conditions. Furthermore, the UV spectral characteristics indicate that the molecular weight of dissolved organic matter in the culture tank of toxic FACHB-905 is greater than that of FACHB-469. Additionally, the humification index of toxic FACHB-905 is slightly higher as well, which suggests that it is more stable in the presence of dissolved organic matter during blooms. Therefore, the toxic Microcystis strain is more likely to become the dominant species in water blooms under lower eutrophic conditions and water blooms formed by the toxic Microcystis strain may be more difficult to recover from.

Urban environmental quality and wellbeing in the context of incomplete urbanisation in Brazil: Integrating directly experienced ecosystem services into planning