Small-scale species patterns and associations in an alvar limestone grassland on Öland, Sweden

This paper reports on the results of a transect analysis carried out in order to detect small-scale patterns ofAvenetum species in a limestone grassland on the Great Alvar on the Baltic island of Öland, Sweden. Three transects consisting of 500 10×10 cm quadrats were used. The cover and number of flowering stalks (if any) of the 21 most common species were recorded. In addition the total cover of vascular plants, cover of mosses and lichens, cover of cow dung and soil depth in each quadrat were recorded. Ellenberg indicator values for light, moisture, reaction and nitrogen were calculated for each quadrat as weighted averages of the values for the species included in the analysis. Patch size frequency analysis, PASFRAN, a new method for detecting patches and their sizes, revealed that 42% of all significant species patches detected had mean patch sizes (diameter) in the range of 26–50 cm, which matched the size of dung patches—49 cm in transect 1 and 30 cm in transect 2. Results of association analysis revealed correlations for several species pairs and between species and environmental factors with similar patch sizes. Combination of PASFRAN and association analysis is recommended as an effective method for pattern detection.     

Periodic droughts and long-term dynamics of alvar grassland vegetation on Öland,Sweden

Dynamics of vegetation was studied on Stora Alvaret in Öland, Sweden, in comparison with precipitation in the May–July part of the growing period. Three data sets representing three main life forms (shrub, dwarf-shrub, and herbs) were collected. species composition eight grassland permanent plots (1969–1993, ass.Veronica spicata-Avenula pratensis), survival and health status ofJuniperus communis (1975–1993), andCalluna vulgaris cover at two permanent plots for the same period. Mortality ofJuniperus andCalluna and proportion of annual species were synchronized and correlated with severe droughts. *** DIRECT SUPPORT *** A02DO006 00003     

Is vascular plant species diversity a predictor of bryophyte species diversity in Mediterranean forests?

This study aimed to (i) investigate the congruence among the species composition and diversity of bryophytes and vascular plants in forests; (ii) test if site prioritization for conservation aims by the maximization of the pooled number of vascular plant species is effective to maximize the pooled number of bryophyte species. The study was performed in six forests in Tuscany, Italy. Four-hundred and twenty vascular plant species (61 of which were woody) and 128 bryophyte species were recorded in 109 plots. Despite the good predictive value of the compositional patterns of both woody plants and total vascular with respect to the compositional pattern of bryophytes, the species richness of the latter was only marginally related to the species richness of the former two. Bryophyte rare species were not spatially related to rare plant species and neither coincided with the sites of highest plant species richness. The species accumulation curves of bryophytes behaved differently with respect to those of woody plants or total vascular plants. Reserve selection analysis based on the maximization of the pooled species richness of either woody plants or total vascular plants were not effective in maximizing the pooled species richness of bryophytes. This study indicates that species diversity of vascular plants is not likely to be a good indicator of the bryophyte species diversity in Mediterranean forests.     

Typing late prehistoric cows and bulls--osteology and genetics of cattle at the Eketorp ringfort on the Öland island in Sweden

Human management of livestock and the presence of different breeds have been discussed in archaeozoology and animal breeding. Traditionally osteometrics has been the main tool in addressing these questions. We combine osteometrics with molecular sex identifications of 104 of 340 morphometrically analysed bones in order to investigate the use of cattle at the Eketorp ringfort on the ?land island in Sweden. The fort is dated to 300-1220/50 A.D., revealing three different building phases. In order to investigate specific patterns and shifts through time in the use of cattle the genetic data is evaluated in relation to osteometric patterns and occurrence of pathologies on cattle metapodia. Males were genotyped for a Y-chromosomal SNP in UTY19 that separates the two major haplogroups, Y1 and Y2, in taurine cattle. A subset of the samples were also genotyped for one SNP involved in coat coloration (MC1R), one SNP putatively involved in resistance to cattle plague (TLR4), and one SNP in intron 5 of the IGF-1 gene that has been associated to size and reproduction.The results of the molecular analyses confirm that the skeletal assemblage from Eketorp is dominated by skeletal elements from females, which implies that dairying was important. Pathological lesions on the metapodia were classified into two groups; those associated with the use as draught animals and those lesions without a similar aetiology. The results show that while bulls both exhibit draught related lesions and other types of lesions, cows exhibit other types of lesions. Interestingly, a few elements from females exhibit draught related lesions. We conclude that this reflects the different use of adult female and male cattle.Although we note some variation in the use of cattle at Eketorp between Iron Age and Medieval time we have found little evidence for the use of different types of animals for specific purposes. The use of specific (genetic) breeds seems to be a phenomenon that developed later than the Eketorp settlement.     

Tree population dynamics,stand structure and species composition in the montane virgin forest of Vallibäcken,northern Sweden

The population dynamics of Betula pubescens and Picea abies in a boreal forest near Kvikkjokk, northern Sweden, are governed by a process of storm gap regeneration similar to the gap regeneration described for boreo-nemoral forests. Cumulative age distribution curves, interpreted as static survivorship curves, lead to a simple theory of differential survival based on properties of the species, i.e. shade tolerance and relative growth rate. The theory is sustained by diameter and height distributions and by the spatial distributions of logs and of trees in different life-phases. Species of the field and ground layers respond differentially to gap formation and the ensuing successional stages. Browsing by moose (Alces alces) may prevent tree species, mainly Sorbus aucuparia, Betula pubescens and Pinus sylvestris, from developing into a tree layer. The regeneration ability for tree species growing in a stand at 460 m a.s.l. is limited compared with the regeneration at 330 m a.s.l., and typical storm gap formation involving more than one tree seems to occur rarely if at all, while overthrown trees with exposed rootplates are uncommon. Spruce at 460 m a.s.l. shows also a lower growth rate and a lower height/diameter ratio compared to the lower situated stands.     

The pristine rain forest? Remnants of historical human impacts on current tree species composition and diversity

Abstract Aim Tropical rain forests are often regarded as pristine and undisturbed by humans. In Central Africa, community‐wide disturbances by natural causes are rare and therefore current theory predicts that natural gap phase dynamics structure tree species composition and diversity. However, the dominant tree species in many African forests recruit poorly, despite the presence of gaps. To explain this, we studied the disturbance history of a species‐rich and structurally complex rain forest. Location Lowland rain forest in Southern Cameroon. Methods We identified the recruitment conditions of trees in different diameter classes in 16 ha of species‐rich and structurally complex ‘old growth’ rain forest. For the identification of recruitment preference we used independent data on the species composition along a disturbance gradient, ranging from shifting cultivation fields (representing large‐scale disturbance), to canopy gaps and old growth forest. Results In nine of sixteen 1‐ha forest plots the older trees preferred shifting cultivation fields for recruitment while younger trees preferred gaps and closed forest conditions. This indicates that these nine sites once experienced large‐scale disturbances. Three lines of evidence suggest that historical agricultural use is the most likely disturbance factor: (1) size of disturbed and undisturbed patches, (2) distribution of charcoal and (3) historical accounts of human population densities. Main conclusions Present‐day tree species composition of a structurally complex and species‐rich Central African rain forest still echoes historical disturbances, most probably caused by human land use between three to four centuries ago. Human impact on African rain forest is therefore, contrary to common belief, an issue not of the last decades only. Insights in historical use will help to get a more balanced view of the ‘pristine rain forest’, acknowledging that the dualism between ‘old growth’ and ‘secondary’ forest may be less clear than previously thought.     

An unusual process structure in Tresarcus, a new acritarch genus from the Ordovician of Öland, Sweden

Tresarcus, a new monospecific acritarch genus, is established along with the type-species Tresarcus suecicus sp. nov. It was found in samples from the upper Arenig (Lenodus sp. A conodont Zone) of the Hagudden and Horns Udde sections, ?land, Sweden. The three-arched process tip is a peculiar characteristic of Tresarcus. This structure recalls, from a morphological point of view (though at a different dimensional scale), the four-arched termination of the epidermal hairs that ornate the adaxial (upper) surface of the assimilating leaves of Salvinia natans, Adanson, 1785 (Pteridophyta). This species has an aquatic habit and the four-arched structure as the tip of the epidermal is interpreted as a device that favours buoyancy by trapping air on the leaf surface. A similar function is hypothesized for the three-arched processes of Tresarcus.     

New light on the floristic composition and diversity of indigenous territory and national park Isiboro-Sécure, Bolivia

A floristic inventory of woody plants was conducted in the tropical forest vegetation of Indigenous Territory and National Park Isiboro-Sécure, Bolivia. All stems with a diameter at breast height ≥2.5 cm were sampled in two terra firme and two floodplain 0.1 ha forest transects, resulting in a total of 447 species and 1,564 individuals. Results correspond fairly well with other Bolivian and neotropical studies in terms of species distribution patterns, physiognomy, family distribution, growth forms, as well as species and family richness. Our finding that only 6% of all species occurred in all four transects, while 69% was found in only one transect, supports the hypothesis that Amazonian plant communities are dominated by a limited set of species, whereas the large majority of species follows a patchy distribution. However, Fisher’s Alpha index values were much higher than was expected from literature data. It is hypothesized that this might be related to high local precipitation levels and/or natural and (historical) anthropogenic disturbance regimes. Although much more research is necessary, our results suggest that TIPNIS represents a strongly underestimated local center of plant diversity.     

Tree diversity,congruence and endemism: Himalaya ‘The land of diversity’

Trees are acknowledged as most valued gift of nature and saviour of earth, enhancing and protecting landscapes, ecosystems and production systems. An authentic database of tree flora missing from local to global scale has immense value. Formulation of conservation and management policies are difficult owing to huge variation in number of species, lack of tree cover and quantification of tree diversity. To endow with a pragmatic groundwork for quantification of tree diversity of IHR, we had published an inventory of 1466 tree species (Angiosperms and Gymnosperms) along with their taxonomically vetted scientific name, distributional range, phenological attributes (leaf persistence and flower colour), use value, congruence, endemism and threatened species. One more database on tree diversity of Western Himalaya was also published with an annotated list of tree flora compiled from unrestricted literature and e-floras related to the regions. The present paper is an attempt to bring out the overall representation of tree flora of IHR, its distributional pattern, congruence, and endemism criterion in Western and Eastern Himalaya along with correlation between the regions as well as states.

     

Structure,zonation, and species diversity of the mayfly communities of the Belá River basin,Slovakia

Four mayfly taxocoena which correspond to zones in the river continuum concept of Vannote et al. (1980) and to the zonation concept of Illies & Botoaneanu (1963), were distinguished by cluster analysis in the Belá River basin, Slovakia.By principal components analysis, taxocoena were shown to be separated along a complex gradient dominated by altitude and slope.An increase of species diversity was observed downstreams. The species-diversity data can be fitted to a geometric series, and interpreted by the niche preemption hypothesis. Equitability and the ratio of Baetidae to Heptagenidae are supposed to indicate ecological conditions.     

The influence of species diversity on ecosystem productivity: how,where, and why?

The effect of species diversity on ecosystem productivity is controversial, in large part because field experiments investigating this relationship have been fraught with difficulties. Unfortunately, there are few guidelines to aid researchers who must overcome these difficulties and determine whether global species losses seriously threaten the ecological and economic bases of terrestrial ecosystems. In response, I offer a set of hypotheses that describe how diversity might influence productivity in plant communities based on three well-known mechanisms: complementarity, facilitation, and the sampling effect. Emphasis on these mechanisms reveals the sensitivity of any diversity-productivity relationship to ecological context (i.e., where this relationship should be found); ecological context includes characteristics of the surrounding environment, temporal and spatial scales of observation, and the intensity of human management. In particular, the legitimacy of the sampling effect as a mechanism of productivity enhancement is dependent upon the degree to which stochastic events influence immigration and extinction processes in a given ecosystem. A mechanistic approach also requires that the three mechanisms be separated and quantified in diversity experiments, and I examine the most appropriate analyses for doing so, focusing on the overyielding technique. Finally, I question why productivity per se is a relevant management concern in non-agricultural systems once relationships among diversity, productivity, and the qualities of the surrounding environment are considered.     

Effect of land use on the structure and diversity of riparian vegetation in the Duero river watershed in Michoacán,Mexico

Riparian vegetation performs important ecosystem functions, since it maintains regional biodiversity and provides a range of environmental services. However, anthropogenic activity, land use type, and edge effects are factors that modify the riparian species assemblage and properties. The present study analyzes the influence of adjacent land use on the structure and diversity of riparian vegetation in four hydrographic regions that form the watershed of the river Duero, in the state of Michoacán, Mexico. Using a survey of woody plants of dbh ≥ 2.5 cm in ten different 0.1 ha sites, we found that the average number of stems and individuals was lower under agricultural (AGR) and urban (URB) land use, compared to forested areas (FOR). The proportion of multistemmed plants differs among land uses: this value was greater in AGR than in the FOR and URB categories. This proportion also differed among the four hydrographic regions. The land use type FOR presented the highest alpha and beta diversity, with a high number of native species occurring only in areas defined by this land use. The results indicate that the category FOR plays an important role in the conservation of regional flora and is a possible source of germplasm for restoration programs in sites degraded by human disturbance. This study shows how anthropogenic activities affect riparian vegetation and highlights the importance of further study of this ecosystem to apply sustainable management strategies that are compatible with its conservation.     

Using the Zeta (ζ) diversity approach for understanding the effects of variations in climatic covariates,vegetation patterns,and human influence on species composition of arboreal frogs in India

The biodiversity patterns of an ecosystem provide an opportunity for understanding the drivers of the community structure and, together, interpreting better conservation strategies for the species. Here we map the patterns in compositional turnover of the arboreal frog species (Anura: Rhacophoridae) in India and explore the impacts of climatic covariates, vegetation patterns, and human influence on driving their species composition. Using the previously published data, we compiled the occurrence matrix for the species of nine genera of the family Rhacophoridae from India. The species turnover trends were analyzed using the zeta diversity decline and retention-rate analysis. We further used the multisite generalized dissimilarity modeling (MS-GDM) to test the variations in climatic, vegetational, and anthropogenic drivers that better explain the species turnover. The results suggested a low nestedness among the genera of arboreal frogs barring Polypedates and Raorchestes. The difference in the mean temperature of the warmest quarter in the colder temperature regime is the primary driver of the compositional turnover of arboreal frog species. Also, differences in the precipitation seasonality of the lower and higher precipitation regime emerged as a driver of the compositional turnover for some genera. The differences in diversity patterns and their corresponding drivers are ideally only species-specific or group-specific. We suggest their utility while designing conservation efforts for co-occurring groups in a region.     

What is the impact of Impatiens parviflora on diversity and composition of herbal layer communities of temperate forests?

The aim was to estimate the impacts of invasive Impatiens parviflora on forests' herbal layer communities. A replicated Before-After-Control-Impact field experiment and comparisons with adjacent uninvaded plots were used. The alien's impact on species richness was tested using hierarchical generalized mixed effect models with Poisson error structure. Impact on species composition was tested using multivariate models (DCA, CCA, RDA) and Monte-Carlo permutation tests. Removal plots did not differ in native species richness from neither invaded nor adjacent uninvaded plots, both when the treatment's main effect or its interaction with sampling time was tested (Chi(2)?=?0.4757, DF?=?2, p?=?0.7883; Chi(2)?=?7.229, DF?=?8, p?=?0.5121 respectively). On the contrary, ordination models revealed differences in the development of plots following the treatments (p?=?0.034) with the invaded plots differing from the adjacent uninvaded (p?=?0.002). Impatiens parviflora is highly unlikely to impact native species richness of invaded communities, which may be associated with its limited ability to create a dense canopy, a modest root system or the fact the I. parviflora does not represent a novel and distinctive dominant to the invaded communities. Concerning its potential impacts on species composition, the presence of native clonal species (Athyrium filix-femina, Dryopteris filix-mas, Fragaria moschata, Luzula luzuloides, Poa nemoralis) on the adjacent uninvaded plots likely makes them different from the invaded plots. However, these competitive and strong species are more likely to prevent the invasion of I. parviflora on the adjacent uninvaded plots rather than being themselves eliminated from the invaded communities.     

Sedimentation of river-transported particles in the Öre estuary,northern Sweden

Sedimentation of river transported particles in the Öre Estuary was studied during spring flow (April–May, 1989). River input was calculated as the product of discharge and particle concentration in the river water. The concentration of suspended matter in the estuary water was determined with a light-scattering probe at 25 depth profiles throughout the estuary. The sedimentation was measured using sediment traps on 5 stations along a line from the river mouth to the mouth of the estuary. Sampling was carried out on four dates with different water discharge.The extension of the particle plume varied during the observation period mainly due to variation in river discharge. The maximum extension of the river plume occurred during the peak of the spring flow and covered approximately 70% of the estuary area. The sedimentation rates were generally high and the average retention time for a particle in the water column was less than 1 day which verifies that the river transported fine-grained particles are primary deposited within the estuary. The major part of the river input of suspended matter was deposited near the river mouth. There was a surplus of the total sedimentation compared to the river input which was due to wave-induced resuspension, especially in the eastern part of the estuary.     

What determines species composition and diversity of hypogeous fungi in the diet of small mammals? A comparison across mammal species,habitat types and seasons in Central European mountains

Interactions between diverse groups of organisms influence the functioning and diversity of ecosystems. Salient examples of such relationships are those among hypogeous fungi, trees and mycophagous mammals. To investigate the role of small mammals in transporting fungal spores within and outside forests as well as the influence of seasons, habitats and species on small mammal mycophagy, we set up a study in the Pieniny Mts, Western Carpathians (Southern Poland). The droppings of small mammals were collected during live trapping in July and September 2016 and 2017, to analyze richness, composition and frequency of fungal spores present in faeces. The yellow-necked mouse Apodemus flavicollis, the bank vole Myodes glareolus and the common vole Microtus arvalis were the most frequently trapped. Spores of 27 fungal taxa from 16 genera were retrieved from nearly 70% of faecal samples of rodents and shrews, with up to 9 spore taxa recorded per sample. Spore diversity in samples was higher in September than in July, although seasonal variation was year and animal dependent. The highest mean number of fungal taxa per sample was recorded for the bank vole and the yellow-necked mouse, with the former species showing a higher degree of mycophagy. The two rodents differed in the average frequencies of consumed fungi in samples, which could result from some degree of specialization in the choice of particular fungal species, as shown by the laboratory-based experiment. Within particular animal species, differences in the fungal diet were found between seasons. The spores of hypogeous fungi were transported from forests to meadows mostly by the yellow-necked mouse and, to a lesser extent, by the common vole. However, both, the diversity and the number of transported spores diminished with distance from the forest edge.     

El Niño droughts and their effects on tree species composition and diversity in tropical rain forests

In this study I investigated the effects of the extreme, 1997/98 El Niño related drought on tree mortality and understorey light conditions of logged and unlogged tropical rain forest in the Indonesian province of East Kalimantan (Borneo). My objectives were to test (1) whether drought had a significant effect on tree mortality and understorey light conditions, (2) whether this effect was greater in logged than in undisturbed forest, (3) if the expected change in tree mortality and light conditions had an effect on Macaranga pioneer seedling and sapling densities, and (4) which (a)biotic factors influenced tree mortality during the drought. The 1997/1998 drought led to an additional tree mortality of 11.2, 18.1, and 22.7% in undisturbed, old logged and recently logged forest, respectively. Mortality was highest in logged forests, due to extremely high mortality of pioneer Macaranga trees (65.4%). Canopy openness was significantly higher during the drought than during the non-drought year (6.0, 8.6 and 10.4 vs 3.7, 3.8 and 3.7 in undisturbed, old logged and recently logged forest, respectively) and was positively correlated with the number of dead standing trees. The increase in light in the understorey was accompanied by a 30 to 300-fold increase in pioneer Macaranga seedling densities. Factors affecting tree mortality during drought were (1) tree species successional status, (2) tree size, and (3) tree location with respect to soil moisture. Tree density and basal area per surface unit had no influence on tree mortality during drought. The results of this study show that extreme droughts, such as those associated with El Niño events, can affect the tree species composition and diversity of tropical forests in two ways: (1) by disproportionate mortality of certain tree species groups and tree size classes, and (2) by changing the light environment in the forest understorey, thereby affecting the recruitment and growth conditions of small and immature trees.