Analysis of long-term ecological status of Lake Balaton based on the ALMOBAL phytoplankton database

Lake Balaton (Hungary), one of the largest lakes in Europe, has undergone eutrophication and restoration during the last two decades. The first quantitative phytoplankton records date back to the 1930s, and since that time thousands of data have been published or accumulated in counting protocols or computer sheets. These data provide material for both scientific analyses (e.g. effects of global change) and applications (e.g. estimation of reference state for the Water Framework Directive). The ALMOBAL phytoplankton database was developed to provide computing support for these applications. It stores data in standardized forms, handles synonyms and allows analyses to be conducted on the basis of floral records, numbers or biomass. The analysis includes records of about 3000 phytoplankton samples taken during the past 60 years from two representative basins in Lake Balaton. This article represents the first attempt at historical reconstruction of the ecological status and compares it with changes in trophic state and current water quality. The results indicate that the phytoplankton biomass and community structure found in the early 1960s could be regarded as reference conditions. Statistical analyses support the view that late summer phytoplankton assemblages are the most sensitive indicators of trophic change, and clearly show the eutrophication of the lake that occurred from the mid-1970s to the mid-1990s and the restoration during the last decade. An additional advantage is that, since quality estimation is based on relative biomass, the method can be used to reconstruct water quality in cases when counting protocols are available, but some basic data for quantitative estimates are missing.     

Predicting extinction risk of butterflies and moths (Macrolepidoptera) from distribution patterns and species characteristics

An extensive follow-up study of day- and night-active Macrolepidoptera was performed during 2004 at the Kullaberg Nature Reserve located in the south-western part of Sweden. Butterflies were surveyed in an area of 100 km² and night-active moths were trapped in the core area of the reserve. Macrolepidopteran species resident in the area in the 1950s were compared with species resident in the area in 2004. As much as 159 of 597 species (27%) resident in the area in 1950s were not found at all in 2004 and 22 species (4%) had colonised the area. Butterflies exhibited a disastrous decline with a loss of 45% of the fauna, and day-active species had declined more than night-active species had. Species distribution pattern and species characteristics were used to predict the probability that a species had become extinct or colonised the area. Species limited to one or a few food plants, with a short flight-period or restricted to non-forest habitats were all associated with a high extinction risk. Species occurring in fewer European countries and recorded from few provinces in Sweden were all associated with a higher extinction risk compared with ubiquitous species. For expanding species (colonisers), the best predictor was their distribution area in Sweden and colonising species were more likely to be limited to a few provinces in the southernmost part of Sweden. Species extinct from Kullaberg also have decreased in Finland and species that had colonised Kullaberg also have increased in Finland, while the species with no change in Kullaberg are also relatively constant in Finland. Indeed, the macrolepidopteran fauna was severely reduced in the last 50 years and almost 70% of the habitat specialists were lost. For red-listed species the situation was found to be alarming. Almost 70% of red-listed species, resident in the area in the 1950s, was not found in 2004. This study highlights that species composition changes rapidly even in protected nature reserves and that similar changes in the macrolepidopteran fauna seem to occur over large areas.     

Pelagic cephalopods from eastern Australia: species composition, horizontal and vertical distribution determined from the diets of pelagic fishes

The distribution and relative biomass of cephalopods from pelagic waters off eastern Australia was examined between 1997 and 2004 from stomach contents of swordfish, yellowfin tuna and dolphinfish taken in the domestic longline fishery. A total of 38 taxa from 19 families were identified. Comparison of the species composition of the three predators indicated pronounced differences in cephalopod species composition. In swordfish, species of the family Ommastrephidae, particularly Ommastrephes bartramii (Lesueur 1821) and Nototodarus gouldi (McCoy 1888) dominated, whereas a more diverse mix of species was identified from yellowfin-sampled cephalopods. Todaropsis eblanae (Ball 1841) was the main cephalopod sampled from the surface-dwelling dolphinfish. For swordfish-sampled cephalopods, significant relationships were found between biomass and season, fluorescence and year. In yellowfin tuna, cephalopod biomass was significantly correlated with season, area and sea surface temperature. Significant factors differed between predator-sampler, possibly reflecting the limits of the predator, but could also give insights into individual cephalopod species distributions. However, the increase in cephalopod biomass over summer in both swordfish and yellowfin tuna suggested cephalopod biomass was higher over summer in the region.     

Patterns of extinction and persistence of Arctotertiary flora in Iberia during the Quaternary

The native or allochthonous nature of certain extant species of the Iberian Peninsula is a matter of some controversy given our lack of knowledge regarding the survival and extinction processes to which they have been subject. The aim of the present work is to provide a review of the current knowledge regarding these processes during the Quaternary. The Middle Pleistocene Transition was a period of noticeable disappearance of Arctotertiary taxa in the Iberian Peninsula, related to the alteration in glacial cyclicity and climate change, including an increase in the severity of glaciations, a reduction in the length of the interglacial periods, and increased dryness during the coldest times. It is difficult to maintain that human activities played any important part in the complete or near-complete disappearance of some taxa during the Quaternary. In the Late Pleistocene and Holocene, however, the extinction of Cedrus, Picea and Carpinus might be related to climate change, competition with other taxa, and anthropogenic disturbances. In contrast, the extreme reduction or even complete disappearance of Platanus or Syringa seems to be due to natural causes alone. The available geological, molecular and palaeobotanical data suggest that some Arctotertiary taxa persisted over long periods of time during the Quaternary in the Iberian Peninsula. Indeed, the fossil record of one important group of taxa, including Castanea, Ceratonia, Carpinus and Juglans, shows its continued presence throughout the Quaternary.     

崇明岛上沙地区蜘蛛种类及其动态分析

于2011年4月初到2013年10月底,在崇明岛上沙地区选择6个代表性区域,采用捕捉、扣管、扫网和陷阱法对蜘蛛种类进行系统调查和定点采集,共采集蜘蛛标本700头,初步鉴定出蜘蛛63种,隶属13科38属,另有8种鉴定到属。该地区蜘蛛优势种类是跳蛛科、肖蛸科、园蛛科、狼蛛科。文章介绍了蜘蛛种群年度消长规律,同时探讨了不同环境因子的变化对蜘蛛种群的影响,分析表明：蜘蛛种群密度与生境和农药的使用存在显著差异,蜘蛛适宜生存的温度在15℃～35℃,适易的相对湿度在65％-85％。     

Habitat selection by recruits establishes local patterns of adult distribution in two species of damselfishes: Stegastes dorsopunicans and S. planifrons

Local patterns of adult distribution in organisms that disperse young as pelagic larvae can be determined at the time of recruitment through habitat selection or, shortly thereafter, through post-recruitment processes such as differential juvenile survivorship and interspecific competition. This study addresses the importance of habitat selection by recruits in establishing the local pattern of adult distribution in two sympatric Caribbean damselfish species, Stegastes dorsopunicans and S. planifrons. Both species inhabit shallow reefs but show little overlap in their distribution; S. dorsopunicans predominates in the reef crest and S. planifrons occurs primarily on the reef slope. Furthermore, S. dorsopunicans is associated with rocky substrate, while S. planifrons occupies live coral. The substrate cover follows a similar pattern with coral being much less common on the reef crest than on the reef slope. Monitoring recruitment every other day in reciprocal removal experiments and artificial reefs indicates that the observed pattern of local adult distribution is a product of habitat selection for both species. The presence or absence of conspecifics did not influence recruitment patterns for either species. Stegastes dorsopunicans recruited primarily to shallow, rocky areas, appearing to cue on both substratum type and depth. Stegastes planifrons recruited exclusively to coral substratum independent of depth. These results indicate that local adult patterns of distribution can be explained by habitat selection at recruitment, and that substrate type and depth may be important cues. Received: 27 May 1997 / Accepted: 4 January 1998     

Divergent environmental preferences and areas of sympatry of tick species in the Amblyomma cajennense complex (Ixodidae)

Four species of Neotropical ticks, Amblyomma mixtum, Amblyomma cajennense, Amblyomma tonelliae and Amblyomma sculptum (formerly included in the catch-all name A. cajennense), have an allopatric distribution in much of their range, with areas of parapatry for at least two of them. We inferred the abiotic niches of these organisms using coefficients of a harmonic regression of the temperature and the Normalized Difference Vegetation Index (NDVI, reflecting plant stress) from remotely sensed data from MODIS satellites with 0.05° spatial resolution. Combinations of coefficients describing the phenology of these two variables pointed to divergent niche preferences, compatible with previous events of vicariance among the species. Amblyomma cajennense has been recorded in areas with small variations in temperature and NDVI. The remaining species were recorded in areas with large variations. The maximum environmental niche overlap was ∼73.6% between A. mixtum and A. cajennense and 73.5% between A. tonelliae and A. sculptum. Projecting these inferences on the geographical space revealed probable areas of sympatry or parapatry between A. mixtum and A. cajennense or between A. tonelliae and A. sculptum, the latter of which was confirmed with field collections. The A. sculptum distribution overlaps with that of A. tonelliae in northern Argentina and Paraguay; parapatry occurs at one extreme of the conditions occupied by both species. Compared with areas of allopatry, sites with both species had consistently lower temperatures, except for 10–12 weeks during the summer, and higher NDVI values throughout the year. We hypothesise that the overlap between A. tonelliae and A. sculptum resulted from secondary contact between populations, with A. sculptum adapting to sites with high water availability to balance high summer temperatures. Additional surveys of the areas of spatial overlap among these species are necessary to elucidate the forces driving their evolution and their adaptation to the environment.     

Management and micro-scale landform determine the ground flora of secondary woodlands and their verges in the Tama Hills of Tokyo,Japan

We investigated the influence of management and micro-scale landform on the species composition and richness of ground flora in secondary woodlands and their verges next to paddy fields in the Tama Hills, Tokyo, Japan. Sites representing various micro-scale landforms and different management regimes were sampled. The results of Detrended Correspondence Analysis and Indicator Species Analysis showed that there was no significant difference between management regimes on species composition in head hollow sites. However, species composition was unique in other landform types having the same management regimes. Micro-scale landform units had less effect on species composition than management regime on crest slopes and side slopes of secondary woodlands. A large variation in species composition of verges, all on the lowermost side slopes, was found within sites, but the composition was different when compared with other sites. We recognized five habitat types associated with species composition that resulted from the combined effects of landform and management regimes. Among habitat types, the verges and the well-managed woodlands had high species richness. Management practices within woodlands have enhanced the species richness on crest slopes and side slopes. High beta diversity of ground flora could be due to the variation in micro-scale landform along soil moisture regimes. Intensive management involving clear-cutting on the lower side slopes (an ecotone of mesic and wet environments) accompanied by paddy cultivation on valley bottoms enhanced the diversity of herbaceous vegetation in the verges.     

Local coexistence of tree species and the dynamics of global distribution pattern along an environmental gradient: a simulation study

A spatially explicit tree-based model was used to demonstrate the effects of a mechanism promoting multiple-species coexistence on the development of vegetation zonation and its response to climate change. Temporal fluctuation in reproduction was incorporated as the mechanism, which facilitates the persistence of less competitive species. Four hypothetical tree species with different temperature dependencies of seed production were randomly located over a landscape represented by 2,000×40 cells. Each cell can sustain a single tree at most. A zonal distribution pattern emerged corresponding to the temperature gradient along the long axis of the landscape. When there was a temporal variation in seed production, species became distributed over a wider range than that when seed production was constant. When the whole landscape was warmed, the distribution range of each species shifted towards the cool end of the landscape. However, the migration was retarded due to competition for vacant spaces with the remnant species which had dominated the location before the warming. Temporal fluctuation in reproduction facilitated the migration because it enhanced the persistence of minority species and, thus, the invasion and establishment of new species in the area dominated by other species.     

Predicting and mapping the spatial distribution of Chamaecyparis formosensis in central Taiwan in a GIS with species distribution models

Analyzing the relationship between species and environment is always a focal question of ecological research. In recent years species distribution models (SDMs) has been widely used to predict the spatial distribution of species. SDMs are numerical tools that combine observations and species occurrence or abundance with environmental variables to predict the spatial distribution of species across landscapes, sometimes requiring extrapolation in space and time. Chamaecyparis formosensis (Taiwan red cypress, TRCs) is a coniferous species endemic to Taiwan, where it natural grows in the central mountains at moderate to high altitudes of 800–2800 m, and most stands in the range of 1500–2150 m. It is threatened by habitat loss and over-cutting for its valuable timber. To preserve TRCs species and achieve sustainable use of biological resources, we choose TRCs as a target for the study to predict its distribution in central Taiwan.The pure forests of TRCs in the study area were mainly located in Pachsienshan (P), Shouchentashan (S) and Baigou Mountain (B) in central Taiwan, and the distribution data were originally obtained by The Third Survey of Forest Resources and Land Use in Taiwan. Elevation, slope, aspect, and three vegetation indices were derived from both SPOT-5 satellite images and DEM. GIS technique was used to overlay those factors. Discriminant analysis (DA), decision tree (DT) and maximum entropy (MAXENT), three commonly used SDMs, were applied based on above-mentioned six variables to predict the suitable habitat of TRCs, and to evaluate which the best model is in terms of accuracy and efficiency. Three experiment designs (ED1, ED2 and ED3) with different combinations of samples were used for model building and validation. The 200 target samples were collected from the site P–B, B–S and P–S for model building under ED1, ED2 and ED3 respectively, while the 100 samples were collected from the site S, P and B for model validation. All experiment designs had same 1350 background samples. The results showed that the overall accuracy and kappa coefficient of DT (96%, 0.88) was higher than that of MAXENT (91%, 0.70), and their accuracies were better than that of DA (84%, 0.58). All the three models were highly efficient in implementation of model construction and evaluation, while the DT model was difficult for generating the entire predicted map of potential habitat due to its complex conditional sentence. Vegetation indices derived from SPOT-5 satellite images could not improve model accuracy because of its insufficiency of spectral resolution and spatial resolution. High spatial resolution and spectral resolution remotely sensed imagery should be used in our future research to improve model performance and reliability.     

Edaphic factors and plant species distribution in a protected area in the desert of Bahrain Island

Effects of edaphic factors (salinity, pH, Na⁺, K⁺, Ca⁺⁺, CaCO₃, water holding capacity, and grain size) on the spatial distribution of plants were investigated. Soil was sampled at 22 stands. Sixteen plant species were recorded from these stands. Relation between edaphic factors and plant distribution was investigated using correlation statistical analysis. Distribution of some plants was found to be highly correlated with edaphic factor(s).     

Spatio-temporal variation in environmental features predicts the distribution and abundance of Ixodes scapularis

Many species have experienced dramatic changes in both geographic range and population sizes in recent history. Increases in the geographic range or population size of disease vectors have public health relevance as these increases often precipitate the emergence of infectious diseases in human populations. Accurately identifying environmental factors affecting the biogeographic patterns of vector species is a long-standing analytical challenge, stemming from a paucity of data capturing periods of rapid changes in vector demographics. We systematically investigated the occurrence and abundance of nymphal Ixodes scapularis ticks at 532 sampling locations throughout New York State (NY), USA, between 2008 and 2018, a time frame that encompasses the emergence of diseases vectored by these ticks. Analyses of these field-collected data demonstrated a range expansion into northern and western NY during the last decade. Nymphal abundances increased in newly colonised areas, while remaining stable in areas with long-standing populations over the last decade. These trends in the geographic range and abundance of nymphs correspond to both the geographic expansion of human Lyme disease cases and increases in incidence rates. Analytic models fitted to these data incorporating time, space, and environmental factors, accurately identified drivers of the observed changes in nymphal occurrence and abundance. These models accounted for the spatial and temporal variation in the occurrence and abundance of nymphs and can accurately predict nymphal population patterns in future years. Forecasting disease risk at fine spatial scales prior to the transmission season can influence both public health mitigation strategies and individual behaviours, potentially impacting tick-borne disease risk and subsequently human disease incidence.     

Occurrence and ecological characteristics of C4 dicot and Cyperaceae species in the Hungarian flora

The non-graminaceous wild flora of Hungary was screened for C₄ plants by using the stable carbon isotope ratio, the leaf anatomy and the photosynthetic carbon dioxide compensation concentration to determine the photosynthetic pathway type. On the whole, 31 C₄ species (native or naturalized) were found in the Amaranthaceae, Chenopodiaceae, Cyperaceae, Euphorbiaceae, Portulacaceae and Zygophyllaceae families. Together with the 26 C₄ grass species (Poaceae) reported earlier (Kalapos 1991), a total of 57 wild C₄ species occur in Hungary, which forms 2.6 % of the country's angiosperm flora. This figure is somewhat higher than what was expected on climatic grounds, a fact probably due to certain edaphic conditions favouring C₄ plant growth. In Hungary, the C₄ species are predominantly annuals growing in open habitats such as dry grasslands, inland saline areas, temporarily exposed riverbeds and disturbed sites. In comparison with C₃ plants, the C₄ species have higher temperature and light preferences, and their phenology lags behind that of the C₃ plants. These differences might account for C₄ plants being usually excluded from productive biotopes in Hungary, where the C₃ canopy may become closed during the growing season before C₄ plants can start their ontogenetic development. Ecological properties of C₃ and C₄ plants differ considerably in the Cyperaceae, but much less in the Chenopodianceae family. Among C₄ annuals naturalized aliens are common, most of which colonized hungary in the last two centuries. Increasing preponderance of C₄ plants is anticipated in the future as a consequence of possible climate changes and the ever increasing human impact on terrestrial vegetation. This revised version was published online in August 2006 with corrections to the Cover Date.     

Habitat characteristics and the distribution of Odonata in a lowland river catchment in eastern England

The influence of habitat characteristics on the distribution of larval and adult Odonata communities in a lowland river in eastern England was studied. There was a longitudinal distribution of Odonata, with larval assemblages being influenced directly by marginal flow velocity, biochemical oxygen demand (BOD) and phosphate concentrations and indirectly by shade and cover of floating vegetation. Adult populations responded directly to shade, reed cover, amenity-managed land use and bank height, and indirectly to BOD and ammonia concentrations. Distribution patterns were strongly associated with both natural changes along the river system and management impacts. River management practices locally disrupted the natural displacement of species along the river, but whilst some forms of human interference on river systems were beneficial to species richness, the effects on stenotopic species were disadvantageous. To conserve Odonata management emphasis should be on the maintenance of suitable conditions for river specialists.     

Altitudinal distribution patterns of bryophytes in the Canary Islands and vulnerability to climate change

We report the pattern of bryophyte distribution through the elevation gradient of three Canary Islands (Fuerteventura, Tenerife and Gomera) assessing their vulnerability risk to climate change. We considered a conservative scenario of upslope climatic shift of 200–400 m and a drop in the upper limit of the cloud belt from 1500 to 1000 m. Climate change vulnerability was analyzed from the overlap between the predicted shift in isotherms or cloud-belt edges and the current species range, following the Colwell and colleagues's model.Liverworts show narrower ranges and tend to live at lower elevations than mosses. Perennials and long-lived shuttle species establish in the upper localities. Many perennials and most of the long-lived shuttle species grow in cloud forests. Many annual shuttle species and colonists establish in the lowest localities. Colonists also occupy the harsh summit in the highest islands.In accordance with the Colwell model, most elements of this bryoflora appears vulnerable to rapid climatic change. Upland extinction and contraction challenges the bryoflora on the driest, lowest island Fuerteventura; range-shift gaps do this on the highest island Tenerife. Liverworts tend to be more vulnerable to range-shift gaps; mosses are more vulnerable to upland extinction. On the lowest island, perennials and long-lived shuttle species are more vulnerable to upland extinction; perennials are also vulnerable to range-shift gaps. Colonists are most vulnerable to upland contraction or extinction on the high islands Gomera and Tenerife. Annual shuttle species tend to be more vulnerable to lowland attrition on these high, most humid islands. Many elements of the bryoflora of the upper limit of the cloud forests appear to be vulnerable, while most of the flora of other cloud forest areas presumably will not be so affected, with the exception of the most restricted species.A simple model illustrates the feasibility of preliminary assessments of climate change on organisms which show a lack of published detailed information on their distribution and biology. This assessment gains by incorporating estimates of biological attributes.     

Endemic flora biodiversity in the south of the Iberian Peninsula: altitudinal distribution,life forms and dispersal modes

The south of the Iberian Peninsula, with an altitudinal range varying from sea level to 3482m and annual average rainfall ranging from 206 to 2223mm, has 516 vascular endemic species or subspecies, that is, an endemicity rate of 13%. This survey deals with parameters such as species richness, originality, life forms and dispersal modes of these plants, in relation to altitudinal and rainfall gradients. Although most of the endemic plants occur between 600 and 1400m a.s.l. and in the range of 600–1000mm annual average rainfall, floristic originality (rate of endemic taxa per area unit) increases exponentially with altitude. The biological spectrum of this endemic flora does not follow the usual patterns observed either in local floras in the south of the Iberian Peninsula or in other regions of the Mediterranean Basin. Chamaephytes (46.08%) and hemicryptophytes (31.37%) are very abundant, whereas therophytes (11.96%) and phanerophytes (0.98%) are comparatively rare. There is a statistically significant correlation between life form and both altitudinal and rainfall gradients. Chamaephytes reach their highest density rates within 1400–2000m a.s.l., but these records tend to decrease as rainfall rates increase. Abundance of hemicryptophytes is directly dependent on rainfall rates and inversely dependent on temperature. The altitudinal distribution pattern of therophytes is opposite to that of hemicryptophytes, but there is no clear correlation as far as rainfall gradient is concerned. Considering both the endemic plants as a whole and each of the life form groups, the relationships between the dispersal modes used and the altitudinal and rainfall gradients are analysed. Up to 44.51% of the endemic plants do not present evident adaptations to promote the dispersion of their diaspores. However, only in the group of therophytes, whose occurrence is positively related to areas of minor altitude, does this difficulty of dispersion play a significant role in the maintenance of stenochory.     

Tempo-spatial distribution and species diversity of green algae micro-propagules in the Yellow Sea during the large-scale green tide development

From 2008 to 2013, vast green tides mainly composed of Ulva prolifera consecutively invaded the coast of Qingdao (36°06′N, 120°25′E, PR China) in June and July. Previous studies have shown that the early green tides initially formed in the Porphyra yezoensis aquaculture area of the Subei Shoal, southern Yellow Sea. To date, multiple studies have demonstrated that green algae micro-propagules play an important role in the formation of green tides. In this study, we aimed to assess the temporal and spatial distribution of green algae micro-propagules in an extensive area of the Yellow Sea and to determine the species diversity of propagules during the development of the large-scale green tide. We found that the quantity of micro-propagules increased with the free-floating biomass from the initial generation to the development phase of the green tide in mid May. From late May to mid June, the micro-propagule density decreased sharply despite a continuous increase of the floating macroalgae biomass. In addition, our data indicate that the coastal area of the Subei Shoal has always been the distribution center of the micro-propagules, even prior to the large-scale green tide formation. Furthermore, diverse green algae species, including Ulva prolifera, Ulva linza, Ulva flexuosa, Ulva compressa, Ulva pertusa and Blidingia sp., were identified among the micro-propagules in the survey sea area. Finally, we determined that the distribution of U. prolifera micro-propagules is closely related to the floating algal mats and attached macroalgae on Porphyra aquaculture rafts.     

The frequency, distribution and reproductive biology of dioecious species in the native flora of Britain and Ireland

The proportion of dioecious species in the flora of the British Isles has been underestimated in the past, partly because the total number of native species was overestimated and partly because some dioecious species were omitted for various reasons. We estimate that, in a total native angiosperm flora of 1377 species and species-equivalents, 4.3% (59 species) are dioecious, a substantially higher percentage than the previous estimates of 2, 3.1 and 3%. If gymnosperms are included, 4.4% (61 of 1380 species of seed plant) are dioecious. A review of published work shows that few of these dioecious species have been well-studied, and that for some little or no information is available about their sex ratios and reproductive biology.