Showing papers on "Diversity index published in 1997"
TL;DR: The results suggest that SCSU may be used to assess the impact of forestry practices on microbial diversity and community structure by using a subset of carbon substrates.
Abstract: The impact of clear-cutting, scarification, and prescribed burning on forest soil microbial community structure was assessed using sole-carbon-source utilization (SCSU). Organic and mineral soil samples were collected on two dates from Pinus banksiana plots that had been clear-cut, clear-cut followed by prescribed burning, clear-cut followed by scarification, or had not been harvested. Microorganisms were extracted from the soil samples and used to inoculate Gram-negative Biolog® plates. Patterns of substrate metabolism were used to calculate Shannon, Simpson, McIntosh, and related evenness indices. Principal component analysis (PCA) resolved organic and mineral soils. Organic soil exhibited higher metabolic diversity than mineral soil. Scarified plots showed lower diversity on one date, when diversity indices were calculated using all carbon sources, and on both dates when calculated using carboxylic acids, only. The results suggest that SCSU may be used to assess the impact of forestry practices on microbial diversity and community structure by using a subset of carbon substrates.
162 citations
TL;DR: Possible reasons for the high degree of intraspecific genetic variation within this species are discussed and the implications for the conservation and use of its genetic resources are described.
Abstract: Cedrela odorata L. (Spanish cedar), an economically important timber species native to the American tropics, is the focus of increasing conservation concern due to high rates of deforestation within its native range. To assess the extent of the genetic diversity within and between populations of this species, samples were obtained from 10 widely dispersed populations within Costa Rica and analysed for random amplified polymorphic DNA (RAPD) variation. Fourteen 10-mer primers were used to generate 97 polymorphic RAPD bands. Presence/absence data for all bands were subjected to a pairwise genetic distance analysis, according to Jaccard's coefficient, then neighbour-joining cluster analysis was performed on these distances, as was an analysis of molecular variance (AMOVA), to assess levels of differentiation between populations and regions, and Shannon's Diversity Index was used to quantify levels of diversity within and between populations. Results indicated highly significant genetic differentiation (P < 0.004, AMOVA) between populations originating from the North Pacific and Atlantic/South Pacific regions of Costa Rica, with 35.3% of the total variation attributable to a difference between these areas. Little differentiation was recorded between populations from within the same region (P= 0.757, AMOVA), and 65.1% of the total variance was attributable to variation within populations. Estimated values for within-population diversity, calculated as Hpop/Hsp by means of Shannon's Diversity Index, were found to vary greatly between primers, but the overall within-population component of genetic diversity was 0.45. Possible reasons for the high degree of intraspecific genetic variation within this species are discussed and the implications of these results for the conservation and use of its genetic resources are described.
121 citations
TL;DR: Herbicide treatments had high efficacy on the target weed, shifting the plant communities back to a grass-dominated structure, and late season applications, made after most herbicide-susceptible forbs had entered summer drought-induced dormancy, minimized impacts on plant community diversity.
Abstract: A field experiment compared the effects of herbicide treatments (picloram, clopyralid and clopyralid + 2,4-D, each at two timings, at the recommended rates for control of the exotic forb Centaurea maculosa) on the structure and species diversity of native plant communities during an 8-year period in western Montana, USA. Floristic composition of replicated treatment plots was sampled before spraying and for 3 years after the initial herbicide applications at two grassland and two early seral forest sites. Following the third year post-spray measurements, half the treatment plots were randomly selected to be resprayed and community sampling was continued for two more years. Diversity was quantified as species richness and Shannon Diversity Index. Standing crops by growth form were estimated by double sampling at the conclusion of the experiment. Herbicide treatments had high efficacy on the target weed, shifting the plant communities back to a grass-dominated structure. Depressions in plant community diversity were small and transitory. In the third year after the initial applications, there were no significant differences among treatments and some herbicide-treated plots had begun to surpass the untreated plots in community diversity measures. With most treatments, respraying 3-4 years after the initial applications did not reduce plant diversity compared to untreated levels. Late season applications, made after most herbicide-susceptible forbs had entered summer drought-induced dormancy, minimized impacts on plant community diversity. The behaviour of herbicide residues in the soil is described in relation to community-level effects. Implications of the results for exotic weed management in conservation settings are discussed.
100 citations
TL;DR: The log-normal relationship linking species diversity and abundance is an objective standard against which applied ecologists can test ecosystemic integrity, disruption, health, ill-health, and reconstitution.
Abstract: When considered together, the diversity and abundance of biologically similar organisms (e.g. pollinators) within a community, are more powerful in assessing the effects of disruption than when taken separately. The log-normal model of abundance and diversity is illustrated as a tool in applied ecology. Data were collected from sampling pollinating bees over 8 years in 13 blueberry fields in New Brunswick, Canada. These data were used to test the log-normality of the species diversity and abundance relationships with respect to the disruption of communities by applications of the insecticide fenitrothion to nearby forests. Ecosystemic integrity (health) of the lowbush blueberry fields was assessed by using species diversity and abundance in Sugihara's (1980) sequential breakage model. This model was used to test the log-normality of data sets from fields which were affected and unaffected by fenitrothion. On both spatial and temporal bases, fields unaffected by the pesticide fitted well to the log-normal model of species diversity and abundance, whereas affected fields departed from that pattern. Thus, the relationship is useful because the samples from fields affected by fenitrothion presumably represent compromised integrity and decline in ecosystemic health. Shannon-Wiener's hierarchical diversity indices and Jaccard's indices of similarity were found to have little value in measuring ecosystemic health. For the former, none of the indices calculated showed any difference between communities with a log-normal pattern of species diversity and abundance, and those without it. Jaccard's index of similarity was low and similar in all the cases. In general, ecosystemic health should not be narrowly assessed through biodiversity but must include taxonomic and population changes together. The log-normal relationship linking species diversity and abundance is an objective standard against which applied ecologists can test ecosystemic integrity, disruption, health, ill-health, and reconstitution.
97 citations
TL;DR: Investigation of the influence of liquid dairy manure and mineral fertilizer, as well as chisel and moldboard plow tillage systems, in a spring barley monoculture and a 3-yr spring barley-forage rotation found that reduced frequency of tillage and herbicide application; management of the forage stands, especially with regard to their termination; and improved soil resource availability likely explained the increased but more stable diversity of the weed communities in the barley- forage rotation.
Abstract: The development of sustainable farming systems depends on our ability to predict and manage the response of weed communities to changes in cropping practices. A study was established at Normandin, Quebec, Canada, to investigate the influence of liquid dairy manure and mineral fertilizer, as well as chisel and moldboard plow tillage systems, in a spring barley monoculture and a 3-yr spring barley-forage rotation that included red clover and timothy. Weed species richness (Margalef's DMG), evenness (Shannon's E), and diversity (Shannon's H') were examined in these treatments from 1992 to 1995. Nutrient source had no effect on any of the three diversity indices. Evenness values were extremely low in all years, suggesting dominance of a few weed species in most treatments. Weed species richness and diversity generally were greater in the barley-forage rotation compared with the monoculture. Tillage effects on richness and diversity varied with crop rotation. Margalef's DMG and Shannon's H' were greater in 1993 and 1995, but they were lower in 1994 when chisel was compared with moldboard plowing in the monoculture. In 1994, chickweed density was about five times greater in the chisel-plowed monoculture compared with other treatment combinations of rotation and tillage. In 1995, only one species with a density of six plants m−2 occurred in the moldboard-plowed monoculture compared with three to six species and densities of 51 to 832 plants m−2 in the other rotation by tillage treatments. Climatic conditions and herbicide use patterns in the different crop rotation treatments may have contributed to the more dynamic nature of weed species diversity in the barley monoculture. Reduced frequency of tillage and herbicide application; management of the forage stands, especially with regard to their termination; and improved soil resource availability likely explained the increased but more stable diversity of the weed communities in the barley-forage rotation.
90 citations
01 Apr 1997
TL;DR: In this article, the authors used data from fisheries research trawl surveys to examine spatial patterns of species richness, Shannon-Wiener diversity index, and evenness of demersal fish communities in relation to latitude and depth from 80 to 898 m off south-east New Zealand.
Abstract: Recent studies of basin-scale patterns of diversity of benthic macrofauna reported strong latitudinal gradients of diversity in the deep North Atlantic, in contrast to regionally variable patterns in the Southern Hemisphere. Here we use data from fisheries research trawl surveys to examine spatial patterns of species richness, Shannon-Wiener diversity index, and evenness of demersal fish communities in relation to latitude and depth from 80 to 898 m off south-east New Zealand. We found species richness decreased latitudinally within regions in the poleward direction, and increased with depth. Areas of high species richness were concentrated along the margins of the Chatham Rise and were associated with current intensification in regions of enhanced surface phytoplankton pigment concentration. Species richness was highest between the 500 and 1000 m contours on the Chatham Rise, where enhanced surface phytoplankton pigment is associated with a major oceanographic feature, the Subtropical convergence. A predominance of species-rich locations was found on the more steeply shelving northern margin of the Chatham Rise. The regional latitudinal pattern of diversity appears to be correlated with regional production, and to be influenced by mesoscale oceanographic features constrained by the bathymetry, although the proximal causes for high diversity remain speculative.
83 citations
TL;DR: Use of RAPD markers may optimize sampling of genetically divergent accessions for introgression into breeding pools, and identify races and regions with maximum genetic diversity.
Abstract: Analysis of the extent and distribution of genetic diversity in crop plants is essential for optimizing sampling and breeding strategies. We used random amplified polymorphic DNA (RAPD) markers to assess genetic diversity and taxonomic relationships in 190 accessions sampled to represent the cultivated races of sorghum [Sorghum bicolor (L.) Moench]. A high level of variation was detected among cultivated genotypes. Partitioning the genetic variation in cultivated sorghum with Shannon's diversity index revealed that 86% of the total genetic variation occurred among accessions and 14% among races. We also examined the degree of association of accessions with their geographic areas of origin by using Shannon's diversity index. The results indicated that only 13% of the total genetic variation was attributable to divergence among regions. Further tests using principal component analysis also failed to show separation of accessions into discrete racial or geographic groups. Despite such limited differentiation among races or regions, RAPD markers successfully identified races and regions with maximum genetic diversity. For example, accessions within races bicolor and guinea had greater genetic diversity than accessions from race kafir. Accessions from southern Africa had a lower level of genetic diversity than accessions from Far and Middle East, Central and Eastern Africa, and Western Africa. Thus, use of RAPD markers may optimize sampling of genetically divergent accessions for introgression into breeding pools.
71 citations
TL;DR: The natural forests of Yanbaru, in the northern part of Okinawa Island, harbor many endemic and endangered birds and mammals, and are dominated by an evergreen oak, Castanopsis sieboldii, which shows high species diversity and diversity indices tended to increase with forest age.
Abstract: The natural forests of Yanbaru, in the northern part of Okinawa Island, harbor many endemic and endangered birds and mammals, and are dominated by an evergreen oak, Castanopsis sieboldii. The Simpson diversity (D) and equitability index (J′) were calculated using survey data on number of stems (≥ 4.5 cm DBH) of each species found in sample plots. Near-climax old forests (age ≥ 50 yr, without pine trees) showed high species diversity of trees, 0.92 ± 0.01 in D and 0.83 ± 0.05 in J′ for trees of which DBH ≥ 4.5 cm, and 0.81 ± 0.04 in D and 0.75 ± 0.05 in J′ for trees of DBH ≥ 10 cm. These high values are comparable to those of tropical rain forests. Although even young forests showed high species diversity, diversity indices tended to increase with forest age. The U.S. Marine Corps leases the eastern half of Yanbaru which contains most of these near-climax forests. Conservation of natural forests in this area is recommended.
62 citations
TL;DR: It is argued that, when mixing two habitat types A and B, the ratio of these habitats that maximize avian diversity depends on the ratios of species confined to habitat A andB, as well as the number of species favoured by the mixture of A and A.
61 citations
TL;DR: The Hartland Shale biofacies of the Western Interior basin of the United States have been studied in this paper, where the authors used numerical faunal data to assess species abundance patterns, and a new method of analyzing diversity is introduced that incorporates species richness, Shannon index, and equitability into a single plot.
Abstract: Questions concerning the application of established biofacies models to mid-Cretaceous black shales prompted a study of diversity characteristics in a fauna from the Late Cenomanian Hartland Shale Member, Western Interior basin. Numerical faunal data are used to assess species abundance patterns, and a new method of analyzing diversity is introduced that incorporates species richness, Shannon index, and equitability into a single plot. In addition, numerical simulations designed to emulate the sampling of species-abundance distributions are used to improve data interpretation. The study illustrates how measured diversity results from the combination of primary ecological controls and sampling effects. Proximal offshore assemblages are characterized by high diversity and log series species-abundance patterns, interpreted as truncated (incompletely sampled) log-normal distributions. Primary ecological controls include variable physical/chemical parameters, biological factors such as predation and competition, and intermediate disturbance frequency. Distal offshore assemblages are characterized by low diversity with patterns of species abundance resembling geometric series. These are interpreted as truncated log-series distributions (sampling effect) that reflect dominance of multiple opportunists, abundant resources in a dysoxic environment, and high disturbance frequency. The data are used to develop an ecological model for diversity levels in basinal black shale facies based on the interplay of recruitment, growth rate, tolerance to low oxygen and sulphide, and disturbance frequency (due to fluctuations of the redox boundary). Although certain taxa (chiefly Inoceramidae) evolved highly opportunistic life strategies to exploit basinal paleoenvironments, it was the unpredictable interaction of these four factors that determined diversity patterns. Analysis of Hartland Shale biofacies illustrates the difficulties in applying a strictly linear relationship between paleo-oxygen levels and diversity.
54 citations
TL;DR: Community structure and species abundance patterns suggested that the maturity and species richness increased gradually from south to north, and a low diversity index and evenness were observed in the area of the Antarctic Divergence, whereas the convergence zone showed high diversity andevenness.
Abstract: The present paper describes latitudinal and vertical changes in the composition, abundance and diversity of copepods in the Indian sector of the Antarctic Ocean, during the end of austral summer along a transect on 66°30′E between 43 and 62°S, within three layers (600–0, 200–0, 100–0 m). Highest copepod densities were noted in the central part of the transect, between the Antarctic Divergence and the Antarctic Convergence, with a maximum in the Antarctic Divergence zone, particularly in the upper levels of the water column. A total number of 80 copepod species were identified over the entire survey area. The south end and the central part of the transect comprised a small number of species. North of the Antarctic Convergence, this number increased markedly with the progressive disappearence of those species characteristic of Antarctic waters and their replacement by temperate and subtropical species. Generally, small copepods, particularly Oithona similis, Oithona frigida and Ctenocalanus citer, dominated in numbers in both Antarctic and sub-Antarctic areas. The contribution of large species to total copepod numbers was much lower, with Calanus simillimus in the central part of the transect, Pleuromamma borealis in the subtropical zone and Calanus propinquus in the southern part. Correspondence analysis showed a marked latitudinal gradient in population structure with four groups of samples and species corresponding to four latitudinal zones. Community structure (species richness, relative dominance index, evenness, Shannon species diversity index) and species abundance patterns (as rank-frequency diagrams) suggested that the maturity and species richness increased gradually from south to north. A low diversity index and evenness were observed in the area of the Antarctic Divergence, whereas the convergence zone showed high diversity and evenness. Conversely, the frontal zone showed high diversity and evenness. Distribution appeared unrelated to chlorophyll concentrations and on the large scale was related to the hydrologic characteristics.
01 Jan 1997
TL;DR: The Simpson diversity (D) and equitability index (f) were calculated using survey data on number of stems (> 45 cm DBH) of each species found in sample plots as discussed by the authors.
Abstract: The natural forests of Yanbaru, in the northern part of Okinawa Island, harbor many endemic and endangered birds and mammals, and are dominated by an evergreen oak, Castanopsis sieboldii The Simpson diversity (D) and equitability index (f) were calculated using survey data on number of stems (> 45 cm DBH) of each species found in sample plots Near-climax old forests (age > 50 yr, without pine trees) showed high species diversity of trees, 092 ? 001 in D and 083 ? 005 in / for trees of which DBH > 45 cm, and 081 ? 004 in D and 075 ? 005 in / for trees of DBH> 10 cm These high values are comparable to those of tropical rain forests Although even young forests showed high species diversity, diversity indices tended to increase with forest age The US Marine Corps leases the eastern half of Yanbaru which contains most of these near-climax forests Conservation of natural forests in this area is recommended
TL;DR: In this paper, the distribution and abundance of small mammals in Swaziland in relation to quantified habitat features was described. But the authors did not report any species capture at more than three sites.
Abstract: This paper describes the distribution and abundance of small mammals in Swaziland in relation to quantified habitat features. Eighteen habitat sites were sampled at seven different locations in all four geographical regions of Swaziland. Small mammal diversity (as described by the Shannon diversity index) was positively correlated with vegetation density. A total of twelve species of rodents and seven species of shrews were captured; however, only six species were caught at more than three sites. Small mammal biomasses and densities were highest at the highveld and middleveld sites. Tall grassland at all elevations supported a high diversity of small mammals. Highveld montane forest supported a high biomass and diversity of species, while no species were captured in moist forest in the Lubombo mountains.
TL;DR: In this paper, a measure of divergence (NAD) between the distribution of individuals in a community and a target distribution is presented, and the trade-off between ecological and economic objectives is investigated.
Abstract: A measure of divergence (NAD) between the distribution of individuals in a community and a target distribution is presented. When the latter is uniform, NAD measures evenness and exhibits a strong correlation with the widely used Shannon index. However, NAD offers the capability to incorporate an arbitrary composition in an economic optimization model where the Shannon index is not applicable. An empirical application to optimum management of a multispecies forest is presented, and the trade-off between ecological and economic objectives is investigated.
TL;DR: The evenness and richness components of diversity have been examined and optimal choices of α and β discussed, particularly for the equiprobable and broken-stick models of abundance as discussed by the authors.
TL;DR: A survey was carried out to determine the density and species composition of germinable seed in the surface soil layers of 30 plots within a coniferized lowland woodland in East Kent in order to establish the resources available for habitat creation in the event of some areas being modified during a proposed holiday village development as mentioned in this paper.
Abstract: A survey was carried out to determine the density and species composition of germinable seed in the surface soil layers of 30 plots within a coniferized lowland woodland in East Kent in order to establish the resources available for habitat creation in the event of some areas being modified during a proposed holiday village development. The selected plots included conifer plantations (up to 69 years old), broad-leaved plantations and the semi-natural broad-leaved edges that remain on parts of the perimeter of the site which were used as the control. A total of 13 682 seedlings emerged from the soil samples during the four-month germination trials. Fifty-two species were identified of which eight were ancient woodland indicator species for south-east England. The most abundant species represented in the seed banks were: Juncus effusus, Rubus fruticosus, Carex sylvatica, Betula pendula and Agrostis tenuis. Between-site comparisons of coniferous plots of different ages revealed a marked reduction in the seed species and seed density in plantations over 65 years old. Results of soil nutrient and texture analyses ruled out the likelihood of edaphic factors being responsible for between-site differences in seed bank composition. Seed species richness and diversity (Shannon-Wiener diversity index) were greatest in the semi-natural broad-leaved edges, but the diversity index used also showed that two replanted conifer sites had high values despite few species being present. The usefulness and limitations of diversity indices in the context of seed bank studies is discussed. From the results of the study, management proposals for the site have been put forward in order to maintain floristic diversity and mitigate the impact of the proposed development.
TL;DR: In this article, the authors analyzed landscape elements using aerial photographs taken in different years in the primary and coppice forests in the Fagus crenata forest region of central Japan.
Abstract: In order to clarify the effects of both the social and natural environment on the changes in landscape structure we analyzed landscape elements using aerial photographs taken in different years in the primary and coppice forests in theFagus crenata forest region of central Japan. The present landscape diversity calculated by Shannon's diversity index (H′) appeared to be higher than that observed in photographs from the earlier year. The site with no residential areas and dominated by primary forests had a lower level of landscape diversity than the site which included some residential areas and coppice forests. These results show that the intensity of human activities contributes to changes in landscape diversity. The landscape diversity on private land was higher than that in the national forest, and the changes in landscape structure in the national forest were different from those seen on private land. This suggests that land ownership significantly affects the changes in landscape structure. Topographic factors also affect the changes in landscape structure. Consequently, not only the natural environment (topography), but also the social environment (intensity of human activity and land ownership) strongly influence the changes in landscape structure.
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TL;DR: In this article, the community diversity at different secondary successional stages on the abandoned cropland in Taibaishan,the peak of Qinling Mountains, was measured and studied using the methods of species abundance, Shannon-Wienner index, Pielou's evenness index and Alatalo index.
TL;DR: A significant and positive association was found between diversity of predators and diversity of collector-gatherers, which may be interpreted as the diversity response of predators to the diversity of prey.
Abstract: The longitudinal distribution of predatory macroinvertebrates and their diversity were investigated on boulder, cobble and gravel substrates along the River Kupa, a karstic river in the NW Dinarid area (Croatia). Depending on substrate type and river section, the predator biomass constituted 6.9 % to 20.2 % of the total macro-invertebrate biomass. In the headwater streams more than 80 % of predator biomass was represented by rhyacophilid, perlid and perlodid larvae. In the upper river section Hirudinea species, rhyacophilids and the dipteran larva, Atherix ibis, constituted approximately equal percentages of total predators. In the lower river section Hirudinea species, Odonata larvae, tanipod and ceratopogonid larvae were the most dominant predators. Along the river gradient the increase of predator biomass corresponded with the increase of scraper, collector-gatherer and filterer biomass. The Shannon index of diversity showed that the diversity of predators increased from the source area to the downstream reaches. A significant and positive association was found between diversity of predators and diversity of collector-gatherers. This positive relationship between predators and collector-gatherers may be interpreted as the diversity response of predators to the diversity of prey.
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TL;DR: Large areas of permanent pasture include a large array of environments favourable to the development of the free-living stages of various species of nematodes and age of the farm is unfavourable to the maintenance of all introduced species.
Abstract: Gastrointestinal nematode communities (12 species) of dairy goats were studied in four regions located in the centre of the western part of France. These regions had very similar annual mean temperatures (11 to 12.5 degrees C) but had rainfall accumulations ranging from 600 to 1330 mm per year. Breeding management (area of pastures, number of goats in the flock, the age of the farm, and the size of the initial goat population) was investigated only in the driest region. The number of helminth species and Shannon diversity index were positively correlated to the permanent pasture area and negatively to the age of the farm. Evenness was negatively correlated to the age of the farm and increased with the increasing levels of rainfall. The results are interpreted in the following terms: i) large areas of permanent pasture include a large array of environments favourable to the development of the free-living stages of various species of nematodes; ii) age of the farm is unfavourable to the maintenance of all introduced species as the farms are helminth-isolated and infestation can only occur during the grazing season thus imposing the necessity of successive annual recolonization of the pastures; and iii) free-living stages are very susceptible to dryness and survive better in areas with heavy rainfall.
TL;DR: Monogeneans were the most common parasites in all species of fish examined from all study sites, and fish of the same species showed a high degree of similarity of its parasite fauna regardless of study site, but different hosts had a low similarity of their parasite f flora even within the same study site.
Abstract: The parasite communities of fish in three reservoirs (Temengor, Kenering and Cenderuh) along the Perak River, as well as in the lower Perak, are compared. A total of 36 species, 51 species, 61 species and 58 species of metazoan parasites from six types of fishes common in all studied locations, were obtained in Temengor, Kenering, Cenderuh Reservoirs, and downstream Perak River, respectively. The various criteria (prevalence, mean intensity, diversity index, similarity index and evenness) of the parasite community were highest at the Cenderuh Reservoir, followed by the downstream river, Kenering, and Temengor Reservoirs. Monogeneans were the most common parasites in all species of fish examined from all study sites. Fish of the same species showed a high degree of similarity of its parasite fauna regardless of study site, but different hosts had a low similarity of their parasite fauna, even within the same study site.
TL;DR: In this article, the influence of geographical location on floristic composition, horizontal structure, biomass, species richness, species diversity and values of phytoindicators of the herb layer in pine and mixed pine forest communities along a climatic gradient was investigated.
01 Jan 1997
TL;DR: In this study habitat selection by birds was largely a function of habitat structure and bird foraging methods.
Abstract: The bird communities of four high elevation plant communities were studied at Tatachia, Yushan National Park, Taiwan. The plant communities included a mature primary spruce forest and three seral stages of secondary vegetation that grow after a fire, grassland, pine woodland and mixed coniferous forest. The densities of all 30 bird species found in the four plant communities were estimated by the circular-plot method in July and August, 1990. Each community at different sites shows distinct pattern in species composition, guild structure and bird density. Most species show preference in habitat selection. The avian community parameters roughly followed the succession pattern. Total number of species and total density increase along the succession gradient. The bird community in spruce forest had the highest Shannon diversity index, followed by pine woodland, mixed coniferous forest, and grassland. Evenness indices were highest in pine woodland and grassland, and lowest in mixed coniferous forest and spruce forest. The Bray-Curtis index of similarity between two bird communities decreased as the successional difference between plant communities increased. The bird communities in pine woodland and mixed coniferous forest, intermediate successional stages, had the highest index of similarity (0.55), while the bird communities, grassland and spruce forest, the extreme ends of pyrosere, were least similar (0.25). In this study habitat selection by birds was largely a function of habitat structure and bird foraging methods.
TL;DR: In this paper, the authors used local biota and their ecological attributes as indicators of changing conditions in aquatic ecosystems to classify the Bernam River, Malaysia using a biological diversity index and a pollution index.
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TL;DR: The results indicated that the forest communities showed rich floristic composition, and high diversity index being up to 5.8-6.3 for 2 primary stands and 4.5-4.8 for 3 regenerated stands as calculated by the Shannon-Wiener diversity index as discussed by the authors.
Abstract: Some basic characteristics of tropical mountain rain forest communities with emphasis only on tree layer of primary and regenerated stands in Jianfengling, Hainan Island, were studied since 1983. The results indicated that the forest communities showed rich floristic composition, and high diversity index being up to 5.8-6.3 for 2 primary stands and 4.5-4.8 for 3 regenerated stands as calculated by the Shannon-Wiener diversity index.Over 8O% of the total genera in the conununities were of tropical components. The diameter at breast height and tree height classes showed a reasonable distribution in the primary and regenerated stands. Based on the results of frequency measurement, the frequency va1ues of most tree populations (more than 8o% of the totals) were less than O.2 in the communities,and the frequency distribution showed the special pattern that was different from the Raunkiaer's Frequency Law.
01 Jan 1997
TL;DR: The spiders inhabiting the ground surface of a citrus orchard were studied by using_fall traps for two years and the diversity index and species richness increased during the warmer months of the year while the evenness index value was low during these months.
Abstract: The spiders inhabiting the ground surface of a citrus orchard were studied by using_fall traps for two years. A total of 912 specimens representing 29 species and eight families was collected. Nearly 86% of population was due to family Lycosidae alone. Three species viz. Pardosa birmanica (31.9%), Pardosa oakleyi (20.5%) and Lycosa vulgaris (2.8%) were the most dominant species which jointly constituted 74.2% of the total number of the spiders caught. The diversity index and species richness increased during the warmer months of the year while the evenness index value was low during these months.
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TL;DR: In the tropics, communities of subcortical arthropods were more diverse in La Selva, Costa Rica, than on Barro Colorado Island, Panama, and compared to Panamanian communities, Costa Rican ones supported higher measures of both species richness and evenness.
Abstract: Species diversity of subcortical arthropod communities were assessed in two tropical regions and two temperate regions. In the tropics, communities of subcortical arthropods were more diverse in La Selva, Costa Rica, than on Barro Colorado Island, Panama. Costa Rican communties yielses higher values of both Shannon and Simpson diversity indices than Panamanian communities. Compared to Panamanian communities, Costa Rican ones supported higher measures of both species richness and evenness. Between the two temperate regions, communities of subcortical arthropods in Korea scored consistently higher values of both Shannon and Simpson indices than the ones in eastern Massachusetts, U.S.A. When individual diversity components were compared, however, Korean communities yielded exceptionally high evenness measures but lower species richness than the communities in the U.S.A. Unusually high evenness values of Korean subcortical arthropods were due to extremely low population densities of all component species.
Journal Article•
TL;DR: A census to bird species diversity was conducted in fragmented rainforest patches at Xishuangbanna,Yunnan Province, China from October to November,1993, and from March to May,1994 as mentioned in this paper.
Abstract: A census to bird species diversity was conducted in fragmented rainforest patches at Xishuangbanna,Yunnan Province,China from October to November,1993,and from March to May,1994.The sample localities were Mane Holy Hill (3 ha) and Chengzi Holy Hill (4 ha) at Menglun,Mengla county,and Manyangguang Holy Hill (20 ha) at Xiaojie,Jinghong County.The control locality was a part of Xishuangbanna National Nature Reserve at Menglun (census area was about 100 ha).104 species,which belonged to 27 families (4 subfamilies),8 orders,were recorded in above localities.In the reserve,89 species were observed.At Manyangguang Holy Hill,30 species were found.Both at Mane and Chengzi Holy Hills 38 species were recorded.The Shannon index was highest at the reserve,while it was lowest at Manyangguang.At Mane the Shannon index was slightly higher than at Chengzi,but a t-test showed they were not significantly different.The change in trend of evenness was similar to that of Shannon index.11 species were common at all four localities.The species found at all three holy hills were also those 11 species.The number of species recorded at both the reserve and Chengzi were the highest (36 species),while the number of species recorded at both Manyangguang and Chengzi was the lowest (13 species).A dendrogram constructed by using the Jaccard index showed that similarity between Chengzi and the reserve was the highest (0.3956),while similarity between Mane and Manyangguang was the second highest (0.3878).This is probably because habitats around Mane and Manyangguang were similar to each other.Both sites were surrounded by farm land and rubber plantation.There was a large secondary forest at one side of Chengzi.This showed that the more similar the surrounding habitats,the more common the species at the two localities were.A dendrogram constructed by using the Sorenson quantitative index also showed that similarity of Mane to Manyangguang were the highest,Chengzi had a higher similarity to them than to the reserve.The reason for this was that the size of all three holy hills were small and the species number were low.However,Mane(3 ha) was more similar to Manyangguang (20 ha) than to Chengzi (4 ha).This showed the surrounding habitat also was one of factors affecting the Sorenson quantitative index,at least in small rainforest patches.A dendrogram constructed by using the Morisita-Horn index showed that there was highest similarity between Mane and reserve.Chengzi had a higher similarity to them.Manyangguang had the lowest similarity to all other localities.The change in trends of similarity was similar to that of their distance to larger primitive rainforest.Bird species number and Shannon index had the similar change trend as the plant species number and Shannon index.The 5 factors,pathch size,the distance to large primitive forest,plant community and diversity,human disturbance,and the habitats surrounding the patches,had influence on bird abundance and diversity in small rainforest patches.