Showing papers on "Diversity index published in 2015"

Pollen diversity captures landscape structure and diversity

Abstract: Summary 1. Past changes in plant and landscape diversity can be evaluated through pollen analysis, however, pollen-based diversity indexes are potentially biased by differential pollen production and deposition. Studies examining the relationship between pollen and landscape diversity are therefore needed. The aim of this study was to evaluate how different pollen-based indexes capture aspects of landscape diversity. 2. Pollen counts were obtained from surface samples of 50 small- to medium-sized lakes in Brandenburg (north-east Germany) and compiled into two sets, with one containing all pollen counts from terrestrial plants and the second restricted to wind-pollinated taxa. Both sets were adjusted for the pollen production/dispersal bias using the REVEALS model. A high-resolution biotope map was used to extract the density of total biotopes and different biotopes per area as parameters describing landscape diversity. In addition, tree species diversity was obtained from forest inventory data. 3. The Shannon index and the number of taxa in a sample of 10 pollen grains are highly correlated and provide a useful measure of pollen type diversity which corresponds best to landscape diversity within one km of the lake and the proportion of non-forested area within seven km. Adjustments of the pollen production/dispersal bias only slightly improve the relationships between pollen diversity and landscape diversity for the restricted data set as well as for the forest inventory data and corresponding pollen types. 4. Using rarefaction analysis, we propose the following convention: pollen type diversity is represented by the number of types in a small sample (low count e.g. 10), pollen type richness is the number of types in a large sample (high count e.g. 500), and pollen sample evenness is characterized by the ratio of the two. 5. Synthesis. Pollen type diversity is a robust index that captures vegetation structure and landscape diversity. It is ideally suited for between site comparisons as it does not require high pollen counts. In concert with pollen type richness and evenness, it helps evaluating the effect of climate change and human land use on vegetation structure on long timescales.

The Link between Microbial Diversity and Nitrogen Cycling in Marine Sediments Is Modulated by Macrofaunal Bioturbation.

Abstract: Objectives : The marine benthic nitrogen cycle is affected by both the presence and activity of macrofauna and the diversity of N-cycling microbes. However, integrated research simultaneously investigating macrofauna, microbes and N-cycling is lacking. We investigated spatio-temporal patterns in microbial community composition and diversity, macrofaunal abundance and their sediment reworking activity, and N-cycling in seven subtidal stations in the Southern North Sea. Spatio-Temporal Patterns of the Microbial Communities : Our results indicated that bacteria (total and beta-AOB) showed more spatio-temporal variation than archaea (total and AOA) as sedimentation of organic matter and the subsequent changes in the environment had a stronger impact on their community composition and diversity indices in our study area. However, spatio-temporal patterns of total bacterial and beta-AOB communities were different and related to the availability of ammonium for the autotrophic beta-AOB. Highest bacterial richness and diversity were observed in June at the timing of the phytoplankton bloom deposition, while richness of beta-AOB as well as AOA peaked in September. Total archaeal community showed no temporal variation in diversity indices. Macrofauna, Microbes and the Benthic N-Cycle : Distance based linear models revealed that, independent from the effect of grain size and the quality and quantity of sediment organic matter, nitrification and N-mineralization were affected by respectively the diversity of metabolically active beta-AOB and AOA, and the total bacteria, near the sediment-water interface. Separate models demonstrated a significant and independent effect of macrofaunal activities on community composition and richness of total bacteria, and diversity indices of metabolically active AOA. Diversity of beta-AOB was significantly affected by macrofaunal abundance. Our results support the link between microbial biodiversity and ecosystem functioning in marine sediments, and provided broad correlative support for the hypothesis that this relationship is modulated by macrofaunal activity. We hypothesized that the latter effect can be explained by their bioturbating and bio-irrigating activities, increasing the spatial complexity of the biogeochemical environment.

Mapping and determinism of soil microbial community distribution across an agricultural landscape

Abstract: Despite the relevance of landscape, regarding the spatial patterning of microbial communities and the relative influence of environmental parameters versus human activities, few investigations have been conducted at this scale. Here, we used a systematic grid to characterize the distribution of soil microbial communities at 278 sites across a monitored agricultural landscape of 13 km². Molecular microbial biomass was estimated by soil DNA recovery and bacterial diversity by 16S rRNA gene pyrosequencing. Geostatistics provided the first maps of microbial community at this scale and revealed a heterogeneous but spatially structured distribution of microbial biomass and diversity with patches of several hundreds of meters. Variance partitioning revealed that both microbial abundance and bacterial diversity distribution were highly dependent of soil properties and land use (total variance explained ranged between 55% and 78%). Microbial biomass and bacterial richness distributions were mainly explained by soil pH and texture whereas bacterial evenness distribution was mainly related to land management. Bacterial diversity (richness, evenness, and Shannon index) was positively influenced by cropping intensity and especially by soil tillage, resulting in spots of low microbial diversity in soils under forest management. Spatial descriptors also explained a small but significant portion of the microbial distribution suggesting that landscape configuration also shapes microbial biomass and bacterial diversity.

Evaluation of functional trait diversity for marine zooplankton communities in the Northeast subarctic Pacific Ocean

Abstract: Functional trait diversity relates variation in the structure of biological communities to function and ecosystem processes. Zooplankton occupy a central position in marine food webs, modulating energy availability to higher trophic levels, while themselves affected by environmental variation. The use of traits with functional diversity potentially enables a more mechanistic understanding of variation and regulation of zooplankton communities than is possible with taxonomic diversity alone. Traits for 42 zooplankton species from the northeast subarctic Pacific were assembled from the literature and applied to a 16-year time series from the oceanographic Line P. We assembled traits on body size, ontogeny, habitat and feeding behaviours. Six major functional groupings were identified via a trait-based cluster dendrogram. Several functional diversity indices were also calculated, and compared with analogous taxonomic diversity indices. Analogue diversity indices were significantly correlated. Both types of diversity indices revealed some year-specific “anomalies” which were associated with broad-scale oceanographic and climatic regime shifts. We propose that the functional diversity approach may represent an additional ecological tool with which we can gain further understanding of zooplankton function and trophic linkages in a changing ocean, in part because functional traits are often based on easily measured morphological characters.

Phenotypic diversity in Ethiopian durum wheat (Triticum turgidum var. durum) landraces

Abstract: The phenotypic diversity of 274 Ethiopian durum wheat accessions was analyzed, taking their geographic origins into account. The aim was to assess the extent and patterns of agronomically important phenotypic variation across districts of origin and altitude classes for major qualitative traits using diversity index and multivariate methods. Eight qualitative and three quantitative traits were scored for 2740 plants and analyzed for diversity. The Shannon–Weaver diversity ( H ′) index was used to estimate phenotypic diversity. The estimated H ′ ranged from monomorphic for glume hairiness to highly polymorphic for other traits. The highest (0.86) H ′ was obtained for seed degree of shriveling, possibly indicating the differential responses of the genotypes to water deficit during later growth stages. With respect to district of origin, the highest (0.72) and lowest (0.44) H ′ values were obtained for the Bale and SNNP districts, respectively. With respect to altitude, the highest (0.76) and lowest (0.62) H ′ values were recorded for altitudes 1600–2000 and > 3000 m above sea levels, respectively. Principal components analysis explained substantial variation contributed by district of origin and altitude range. Genotypes were clustered into three groups by districts of origin and altitude class, with relatively strong bootstrap values of 57 and 62 for the former and latter, respectively. It could be concluded that Ethiopian durum wheat landraces are very diverse both within and among districts of origin and altitude classes. This wealth of genetic diversity should be exploited for wheat improvement of yield and for resistance to biotic and abiotic stresses, particularly terminal drought.

Effects of Conservation Agriculture and Fertilization on Soil Microbial Diversity and Activity

Abstract: Soil microbial communities perform critical functions in ecosystem processes These functions can be used to assess the impact of agricultural practices on sustainable crop production In this five-year study, the effect of various agricultural practices on soil microbial diversity and activity was investigated in a summer rainfall area under South African dryland conditions Microbial diversity and activity were measured in the 0–15 cm layer of a field trial consisting of two fertilizer levels, three cropping systems, and two tillage systems Using the Shannon–Weaver and Evenness diversity indices, soil microbial species richness and abundance were measured Microbial enzymatic activities: β-glucosidase, phosphatase and urease, were used to evaluate ecosystem functioning Cluster analysis revealed a shift in soil microbial community diversity and activity over time Microbial diversity and activity were higher under no-till than conventional tillage Fertilizer levels seemed to play a minor role in determining microbial diversity and activity, whereas the cropping systems played a more important role in determining the activity of soil microbial communities Conservation agriculture yielded the highest soil microbial diversity and activity in diversified cropping systems under no-till

The community-level response to sewage impact in intertidal mytilid beds of the Southwestern Atlantic, and the use of the Shannon index to assess pollution

Abstract: A study of an intertidal mytilid community in the Southwestern Atlantic shore was carried out in order to characterize the mytilid bed s response to an intertidal sewage discharge. Four Stations were sampled around the outfall, with a Control site. Total Weight and Organic Carbon content of sediments among mussels, as well as water quality variables were measured. All macrofauna were counted, and species number, Shannon s diversity index and evenness were calculated. The mytilid Brachidontes rodriguezi increases it density inversely to distance to the effluent. The polychaetes Capitella capitata and Boccardia polybranchia characterized the most impacted Stations, while crustaceans (Corophium insidiosum, Jassa falcata and Caprella sp.) were dominant at medial distances. Both environmental and biological data show significative differences between Stations. The most impacted Station has the lowest species number, but the highest values of both diversity and evenness; while control Station has the lowest values of diversity and evenness. The study reject the use of univariate indices to assess organic pollution in this community, being the presence of indicator species with mytilid proportion the best tool for sewage impact assessment.

Diversidade e equitabilidade de Plantas Alimentícias Não Convencionais na zona rural de Viçosa, Minas Gerais, Brasil

Abstract: This study analyzed the diversity and the equity of unconventional food plants (UFPs) in the rural area of Vicosa, Minas Gerais, Brazil. The research was performed using the Snowball sampling with semi-structured interviews, applied to 20 residents from nine rural communities. We evaluated the relative frequency of citation of the species (Fr); the diversity and equity of the same species, using the Shannon-Wiener (H’) and Pielou (J’) indexes, respectively. The species were listed by its family, scientific name, common denominations, propagation environment, growth habit, application methods, domestication state, production cycle and finally registration through consultation in herbaria in the Atlantic Forest biome. We found 59 species of UFPs, distributed in 30 botanical families and 48 genera. The Asteraceae family and the Myrtaceae one stood out for their floristic richness, contributing to 11 and 7 species, respectively. Species from the Asteraceae family got the highest relative frequencies (32.2). It was obtained the Shannon-Wiener diversity index of 1.65 (Base 10), and the Pielou equity index of 0.93. The results are similar to other studies developed in the Atlantic Forest biome, where there was a wide diversity of UFPs in the study area, and the knowledge of these plants is evenly distributed among the residents.

The conservation status and anthropogenic impacts assessments of Mediterranean coastal dunes

Abstract: Mediterranean coastal dunes have been highly modified by human impacts and understanding their conservation status is crucial to preserve these extremely vulnerable habitats. In the present study three different diversity indices elaborated by Grunewald and Schubert (H dune , a modified version of the Shannon diversity index, E dune , a modified Evenness index, and N, the Naturalness index) were applied in order to assess the conservation status and anthropogenic impacts on Is Arenas dune system (CW Sardinia), one of the widest and most important in the Western Mediterranean Basin. Within the system, two sites with different anthropic disturbance conditions were selected; 25 permanent plots were seasonally monitored and the cover of each vascular plant present was visually estimated. The H dune values were similar between sites and differences were not significant; E dune showed higher value in the North than in the South site with relevant statistical differences. Moreover a seasonal variation in the indices values was recorded, which could be linked to presence of annual plants rather than the touristic pressure. Instead, the small variability of N index suggests that the application of this index may be an important tool to assess human impact on coastal dunes, but better discriminates between sites with different disturbance degrees. Our results highlight the usefulness of H dune and E dune indices to assess the conservation status of a Mediterranean coastal dune system, while these indices are less influenced by the human trampling at finer scale (sites within the beach). Spring and summer are the best seasons when the main plant diversity of Mediterranean coastal dune can be captured. The diversity indices applied, although need to be developed through further researches, could be a quickly tool allowing to assess the integrity of the coastal dunes in order to plan management actions of these complex and threatened ecosystems.

Fish diversity in the southern coastal waters of bangladesh: present status, threats and conservation perspectives

Abstract: Despite the enormous anthropogenic and environmental hazards affecting wild fisheries resources, southern coastal waters are still considered one of the aquatic biodiversity hotspots in Bangladesh. Therefore, the present study was conducted to make a complete account of fishes and to assess their condition and conservation status in the rivers spread across four southern coastal districts of Bangladesh. During the study period from January to December 2014, a total of 98 species of fish were recorded belonging to 81 genera, 48 families and 13 orders. Perciforms were recorded as the most diverse fish group in terms of both number and individuals of species observed. Of the 98 species, 26.53% were listed as Locally Threatened in Bangladesh, including 11.22% species listed as Vulnerable, 10.20% as Endangered and 5.10% as Critically Endangered. Four population indices viz, Shannon–Wiener index (H), Simpson’s dominance index (D), Simpson’s index of diversity (1-D) and Margalef’s index (d) were applied to demonstrate the species diversity, richness and evenness of fish in sampling areas and their overall values were 3.54-3.70, 0.04-0.05, 0.95-0.96 and 7.48-8.67, respectively. To sustain the prospect of fisheries biodiversity in the southern coastal areas of Bangladesh, management and conservation strategies like restocking economically important fish species, establishing and maintaining fish sanctuaries, banning indiscriminate fishing and destructive fishing gears, identification and protection of the breeding and nursery grounds should be taken into consideration with utmost priority.

Woody Species Diversity in Traditional Agroforestry Practices of Dellomenna District, Southeastern Ethiopia: Implication for Maintaining Native Woody Species

Abstract: The major impact of humans on forest ecosystems including loss of forest area, habitat fragmentation, and soil degradation leads to losses of biodiversity. These problems can be addressed by integration of agriculture with forests and maintaining the existing forests. This study was initiated to assess woody species diversity of traditional agroforestry practices. Three study sites (Burkitu, Chire, and Erba) were selected based on the presence of agroforestry practice. Forty-eight (48) sample quadrants having an area of 20 m × 20 m, 16 sample quadrants in each study site, were systematically laid using four transect lines at different distance. The diversity of woody species was analyzed by using different diversity indices. A total of 55 woody species belonging to 31 families were identified and documented. There were significantly different ( ) among the study Kebeles (peasant associations). Mangifera indica, Entada abyssinica, and Croton macrostachyus were found to have the highest Important Value Index. The results confirmed that traditional agroforestry plays a major role in the conservation of native woody species. However, threats to woody species were observed. Therefore, there is a need to undertake conservation practices before the loss of species.

Assessment of diversity indices for the characterization of the soil prokaryotic community by metagenomic analysis

Abstract: The diversity indices used in ecology for assessing the metagenomes of soil prokaryotic communities at different phylogenetic levels were compared. The following indices were considered: the number of detected taxa and the Shannon, Menhinick, Margalef, Simpson, Chao1, and ACE indices. The diversity analysis of the prokaryotic communities in the upper horizons of a typical chernozem (Haplic Chernozem (Pachic)), a dark chestnut soil (Haplic Kastanozem (Chromic)), and an extremely arid desert soil (Endosalic Calcisol (Yermic)) was based on the analysis of 16S rRNA genes. The Menhinick, Margalef, Chao1, and ACE indices gave similar results for the classification of the communities according to their diversity levels; the Simpson index gave good results only for the high-level taxa (phyla); the best results were obtained with the Shannon index. In general, all the indices used showed a decrease in the diversity of the soil prokaryotes in the following sequence: chernozem > dark chestnut soil > extremely arid desert soil.

Functional Trait Changes, Productivity Shifts and Vegetation Stability in Mountain Grasslands during a Short-Term Warming

Abstract: Plant functional traits underlie vegetation responses to environmental changes such as global warming, and consequently influence ecosystem processes. While most of the existing studies focus on the effect of warming only on species diversity and productivity, we further investigated (i) how the structure of community plant functional traits in temperate grasslands respond to experimental warming, and (ii) whether species and functional diversity contribute to a greater stability of grasslands, in terms of vegetation composition and productivity. Intact vegetation turves were extracted from temperate subalpine grassland (highland) in the Eastern Pyrenees and transplanted into a warm continental, experimental site in Lleida, in Western Catalonia (lowland). The impacts of simulated warming on plant production and diversity, functional trait structure, and vegetation compositional stability were assessed. We observed an increase in biomass and a reduction in species and functional diversity under short-term warming. The functional structure of the grassland communities changed significantly, in terms of functional diversity and community-weighted means (CWM) for several traits. Acquisitive and fast-growing species with higher SLA, early flowering, erect growth habit, and rhizomatous strategy became dominant in the lowland. Productivity was significantly positively related to species, and to a lower extent, functional diversity, but productivity and stability after warming were more dependent on trait composition (CWM) than on diversity. The turves with more acquisitive species before warming changed less in composition after warming. Results suggest that (i) the short-term warming can lead to the dominance of acquisitive fast growing species over conservative species, thus reducing species richness, and (ii) the functional traits structure in grassland communities had a greater influence on the productivity and stability of the community under short-term warming, compared to diversity effects. In summary, short-term climate warming can greatly alter vegetation functional structure and its relation to productivity.

Biodiversity of culicid mosquitoes in rural Neka township of Mazandaran province, northern Iran.

Abstract: Background & objectives: This paper presents the results of a study on ecological parameters including diversity indices applied on populations of Culicidae mosquitoes (Diptera: Culicidae) from three rural areas (Darvishan, Chalmardi and Khairabad) of Neka township in Mazandaran province, northern Iran. Methods: Adult and larval stages of mosquitoes were systematically sampled to obtain data required for measuring diversity of mosquitoes in these areas. Alfa and beta indices were analyzed to compare mosquito diversity. A total of 5270 specimens belonging to four genera and 14 different species were collected and identified. Results: Evaluation of dominance structure of species showed that culicid mosquitoes of Neka rangelands include one eudominant species, two dominant species, two subdominant species, two rare species and eight subrare species when Heydemann classification was used. Interpretation & conclusion: Data analysis revealed a higher diversity of mosquitoes in Khairabad with a low degree of interspecific dominance, while Darvishan and Chalmardi recorded the lowest observed diversity and a high degree of interspecific dominance. The cluster analysis based on Jaccard’s index indicated the relationship between the categories and indicates that Darvishan and Khairabad are the closest categories in their specific composition.

Taxonomic distinctness and conservation of a new high biodiversity subterranean area in Brazil

Abstract: Subterranean environments, even though they do not possess a primary production (photosynthesis), may present high biodiversity, faunistic originality, endemism, phylogenetic isolations and unique ecological and/or evolution events, in addition to rare taxa. Studies investigating the biological diversity in Neotropical caves are relatively rare and recent, and most of them have been conducted in Brazil. We sampled caves from the state of Bahia, northeastern Brazil, and through sampling sufficiency tests and richness estimators, we demonstrate that the normatization for the Brazilian cave laws is not adequate for its conservation and that only α diversity index is not enough to verify faunistic patterns. We suggest that a phylogenetic diversity index be more robust and accurate for conservation purposes, particularly the Taxonomic Distinctness index. Moreover, we propose that the sandstone complex caves from Chapada Diamantina National Park need to be classified as being of high subterranean biodiversity in a global scope.

The diversity, abundance and habitat association of medium and large-sized mammals of Dati Wolel National Park, Western Ethiopia

Abstract: Knowledge of the faunal diversity, abundance and habitat preference are basics for the status determination and proposing appropriate conservation measures. A survey was conducted to assess the diversity, relative abundance and habitat association of medium and large-sized mammals of the Dati Wolel National Park, Western Ethiopia from September 2012 to April 2013. It was hypothesized that the area is rich in mammalian species that prefer to live in grassland and woodland close to water source. Four habitat types were assessed during the study (wetland, woodland, riverine forest and grassland). Line transect survey method was used to collect data in the four sampled habitats. A total of 28 mammalian species were recorded. Woodland was the habitat with the most diversity of mammals (H’ =2.643) followed by riverine forest (H’ = 1.60677), and the wetland was considered the habitat with the least diversity of species (H’= 1.04086). Hippopotamus amphibius (hippopotamus; 43.92%) and Syncerus caffer (African buffalo; 33.3%) were the most abundant species, while Mellivora capensis (honey badger) and Ichneumia albicauda (black backed jackal) were the least observed (0.099%, each). The greatest species similarity was recorded between woodland and grassland (SI=0.76) and the lowest was between woodland and wetland (SI= 0.4). Thorough inventory for faunal diversity, involving multiple seasons and all vertebrates, strengthening the now loose park management by involving the local people will ensure the sustainability of the ecosystem in supporting the riche biodiversity components. Key words: Diversity indices, evenness, habitat preference, mammals, species richness, transect lines.

Conservation Tillage Affects Species Composition But Not Species Diversity: A Comparative Study in Northern Italy

Abstract: Conservation tillage (CT) is widely considered to be a practice aimed at preserving several ecosystem functions In the literature, however, there seems to be no clear pattern with regard to its benefits on species diversity and species composition In Northern Italy, we compared species composition and diversity of both vascular plants and Carabids under two contrasting tillage systems, ie, CT and conventional tillage, respectively We hypothesized a significant positive impact of CT on both species diversity and composition We also considered the potential influence of crop type The tillage systems were studied under open field conditions with three types of annual crops (ie, maize, soybean, and winter cereals), using a split-plot design on pairs of adjacent fields Linear mixed models were applied to test tillage system, crop, and interaction effects on diversity indices Plant and Carabids communities were analyzed by multivariate methods (CCA) On the whole, 136 plant and 51 carabid taxa were recorded The two tillage systems studied did not differ in floristic or carabid diversity Species composition, by contrast, proved to be characteristic for each combination of tillage system and crop type In particular, CT fields were characterized by nutrient demanding weeds and the associated Carabids The differences were especially pronounced in fields with winter cereals The same was true for the flora and Carabids along the field boundaries For studying the effects of CT practices on the sustainability of agro-ecosystems, therefore, the focus should be on species composition rather than on diversity measures

Bacterial diversity of Drass, cold desert in Western Himalaya, and its comparison with Antarctic and Arctic.

Abstract: Drass is the coldest inhabited place in India and the second coldest, inhabited place in the world, after Siberia. Using the 16SrDNA amplicon pyrosequencing, bacterial diversity patterns were cataloged across the Drass cold desert. In order to identify the ecotype abundance across cold desert environment, bacterial diversity patterns of Drass were further compared with the bacterial diversity of two other cold deserts, i.e., Antarctic and Arctic. Acidobacteria, Proteobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria and Gemmatimonadetes were among the highly abundant taxonomic groups present across all the three cold deserts and were designated as the core phyla. However, Firmicutes, Nitrospirae, Armatimonadetes (former candidate division OP10), Planctomycetes, TM7, Chloroflexi, Deinococcus-Thermus, Tenericutes and candidate phyla WS3 were identified as rare phyla in Drass, Antarctic and Arctic samples. Differential abundance patterns were also computed across all the three samples, i.e., Acidobacteria (32.1 %) were dominant in Drass and Firmicutes (52.9 ± 17.6 %) and Proteobacteria (42 ± 1.3 %) were dominant in Antarctic and Arctic reference samples, respectively. Alpha diversity values Shannon’s (H) and Simpson’s (1-D) diversity indices were highest for Antarctic samples, whereas richness estimators (ACE and Chao1) were maximum for Drass soil suggesting greater species richness in bacterial communities in Drass than the Antarctic and Arctic samples.

Effects of farm size and on-farm landscape heterogeneity on biodiversity-case study of twelve farms in a swedish landscape

Abstract: In this study in Sweden, six small ( 135 ha) participated. The aims of the study were to a) measure differences between small and large farms regarding on-farm landscape heterogeneity, and b) evaluate relations between on-farm landscape heterogeneity and biodiversity, measured as numbers of breeding bird species, bird territories, butterflies, bumblebees, and herbaceous plant species. Sample area of the same size, placed on each farm, was used for the biodiversity assessments and on-farm landscape heterogeneity studies. On-farm landscape heterogeneity was classified with the Shannon–Wiener diversity index. Linear regression was applied to analyze relationships between on-farm landscape heterogeneity and biodiversity indicators. Multivariate regression was used to analyze relations between single bird species and specific on-farm habitats. Small farms had significantly higher on-farm landscape heterogeneity than large farms. Strong positive relations between on-farm landscape h...

Diversity, distribution and vegetative structure of mangroves of the Andaman and Nicobar Islands, India

Abstract: The present study was carried out to determine the diversity, distribution and vegetative structure of mangroves of the Andaman and Nicobar Islands (ANI). The results suggest that mangroves of the ANI consist of 38 mangrove species belonging to 12 families and 19 genera, which includes 4 hybrids and 34 species. In other words, about 50% of the global mangrove species are present in ANI. Andaman Islands have 35 species and Nicobar Islands have 21 mangrove species. The average tree density in ANI is 1746/per hectare and varies from 487 to 2383 per hectare. The Shannon diversity index for the whole ANI is 2.94 and Simpson index is 0.07. Family Rhizophoraceae constitutes an important vegetative component in the mangroves of the ANI followed by Acanthaceae, Lythraceae and Malvaceae. Rhizophora spp. constitutes 19% of the Important Value Index (IVI) and R. apiculata is dominant in ANI. Among the eight forest divisions, mangrove diversity is high in South Andaman (30 species) followed by Middle Andaman (28), Mayabunder (25), Diglipur (25), Nicobar (21), Little Andaman (20), Havelock (20) and Baratang (20). The average mangrove plant density and Shannon diversity index (H’) is high in Middle Andaman (2101/hectare; H’ = 2.93). Species richness index (d’) is high in South Andaman (3.32). Evenness index (J’) is high in Little Andaman (0.92). Simpson dominance index (D) ranged between 0.07–0.1, and this agrees with the high diversity in mangroves of ANI. In all the divisions Rhizophora spp. constitutes a major vegetative component except, Diglipur and Nicobar. In Diglipur Bruguiera spp. are dominant, while in Nicobar Sonneratia spp. are dominant. The low similarity value of the Nicobar division with other divisions indicates the difference in floristic structure of mangroves of the Andaman Islands and Nicobar Islands. The present study also indicates that mangrove of ANI are more diverse in its species composition than the other mangrove habitats in India.

Plant Functional Diversity Can Be Independent of Species Diversity: Observations Based on the Impact of 4-Yrs of Nitrogen and Phosphorus Additions in an Alpine Meadow.

Abstract: Past studies have widely documented the decrease in species diversity in response to addition of nutrients, however functional diversity is often independent from species diversity. In this study, we conducted a field experiment to examine the effect of nitrogen and phosphorus fertilization ((NH4)2 HPO4) at 0, 15, 30 and 60 g m-2 yr-1 (F0, F15, F30 and F60) after 4 years of continuous fertilization on functional diversity and species diversity, and its relationship with productivity in an alpine meadow community on the Tibetan Plateau. To this purpose, three community-weighted mean trait values (specific leaf area, SLA; mature plant height, MPH; and seed size, SS) for 30 common species in each fertilization level were determined; three components of functional diversity (functional richness, FRic; functional evenness, FEve; and Rao’s index of quadratic entropy, FRao) were quantified. Our results showed that: (i) species diversity sharply decreased, but functional diversity remained stable with fertilization; (ii) community-weighted mean traits (SLA and MPH) had a significant increase along the fertilization level; (iii) aboveground biomass was not correlated with functional diversity, but it was significantly correlated with species diversity and MPH. Our results suggest that decreases in species diversity due to fertilization do not result in corresponding changes in functional diversity. Functional identity of species may be more important than functional diversity in influencing aboveground productivity in this alpine meadow community, and our results also support the mass ratio hypothesis; that is, the traits of the dominant species influenced the community biomass production.

Drivers and Patterns of Ground-Dwelling Beetle Biodiversity across Northern Canada.

Abstract: Many macroecological patterns of biodiversity, including the relationship between latitude and species richness, are well-described. Data collected in a repeatable, standardized manner can advance the discipline beyond the description of patterns and be used to elucidate underlying mechanisms. Using standardized field methods and a hyper-diverse focal taxon, viz. Coleoptera, we aim to (1) describe large-scale latitudinal patterns of taxonomic diversity, functional diversity, and assemblage structure across northern Canada, and (2) determine which climatic, spatial, and habitat variables best explain these patterns. We collected terrestrial beetles at twelve locations in the three northernmost ecoclimatic zones in North America: north boreal, subarctic, and high arctic (51–81°N, 60–138°W). After identifying beetles and assigning them to a functional group, we assessed latitudinal trends for multiple diversity indices using linear regression and visualized spatial patterns of assemblage structure with multivariate ordinations. We used path analysis to test causal hypotheses for species and functional group richness, and we used a permutational approach to assess relationships between assemblage structure and 20 possible climatic and environmental mechanisms. More than 9,000 beetles were collected, representing 464 species and 18 functional groups. Species and functional diversity have significant negative relationships with latitude, which are likely explained by the mediating effects of temperature, precipitation, and plant height. Assemblages within the same ecoclimatic zone are similar, and there is a significant relationship between assemblage structure and latitude. Species and functional assemblage structure are significantly correlated with many of the same climatic factors, particularly temperature maxima and minima. At a large spatial extent, the diversity and assemblage structure of northern beetles show strong latitudinal gradients due to the mediating effects of climate, particularly temperature. Northern arthropod assemblages present significant opportunities for biodiversity research and conservation efforts, and their sensitivity to climate make them ideal targets for long-term terrestrial diversity monitoring.

Culicidae community composition and temporal dynamics in Guapiaçu Ecological Reserve, Cachoeiras de Macacu, Rio de Janeiro, Brazil.

Abstract: A temporal observational study was conducted of the Culicidae fauna in a remnant area of Atlantic Forest within a private reserve (Guapiacu Ecological Reserve-REGUA) presenting typical vegetation cover of dense rain forest, with some patches recovering a floristic composition similar to that of the original community. Research was carried out to analyze the influence of climatic factors (mean monthly temperature, rainfall, and air relative humidity) on the temporal dynamics of the mosquito communities that occur in the reserve. The completeness of the mosquito inventory was assessed with individual-based rarefaction-extrapolation curves. Differences in species composition between sites and months were tested with PERMANOVA. True diversities of orders 0, 1, and 2 (effective numbers) were estimated and compared between sites, months, and years. Multiple stepwise regressions were used to assess relationships between climatic variables, measures of diversity, and abundances of the most common species. There were significant interactive effects between year and site on measures of diversity. However, diversity estimates showed little variation among months, and these were weakly correlated with climatic variables. Abundances of the most common species were significantly related to temperature or relative humidity, but not rainfall. The presence of mosquito species known to be vectors of human diseases combined with an intermittent flow of visitors to the study area suggests there is a risk of disease transmission that warrants further monitoring.

Spatiotemporal diversity, structure and trophic guilds of insect assemblages in a semi-arid Sabkha ecosystem

Abstract: The current study highlights some knowledge on the diversity and structure of insect communities and trophic groups living in Sabkha Djendli (semi-arid area of Northeastern Algeria). The entomofauna was monthly sampled from March to November 2006 using pitfall traps at eight sites located at the vicinity of the Sabkha. Structural and diversity parameters (species richness, Shannon index, evenness) were measured for both insect orders and trophic guilds. The canonical correspondence analysis (CCA) was applied to determine how vegetation parameters (species richness and cover) influence spatial and seasonal fluctuations of insect assemblages. The catches totalled 434 insect individuals classified into 75 species, 62 genera, 31 families and 7 orders, of which Coleoptera and Hymenoptera were the most abundant and constant over seasons and study stations. Spring and autumn presented the highest values of diversity parameters. Individual-based Chao-1 species richness estimator indicated 126 species for the total individuals captured in the Sabkha. Based on catch abundances, the structure of functional trophic groups was predators (37.3%), saprophages (26.7%), phytophages (20.5%), polyphages (10.8%), coprophages (4.6%); whereas in terms of numbers of species, they can be classified as phytophages (40%), predators (25.3%), polyphages (13.3%), saprophages (12%), coprophages (9.3%). The CCA demonstrated that phytophages and saprophages as well as Coleoptera and Orthoptera were positively correlated with the two parameters of vegetation, especially in spring and summer. While the abundance of coprophages was positively correlated with species richness of plants, polyphage density was positively associated with vegetation cover. The insect community showed high taxonomic and functional diversity that is closely related to diversity and vegetation cover in different stations of the wetland and seasons.