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Human Population Density (human + population_density)

Distribution by Scientific Domains

Life Sciences	91%
2 Other Domains	9%

Distribution within Life Sciences

Conservation Science	32%
Ecology & Organismal Biology	23%

Selected Abstracts

Could we live with reintroduced large carnivores in the UK?

MAMMAL REVIEW, Issue 3 2004
CHARLES J. WILSON
ABSTRACT 1.,Literature on the wolf Canis lupus, brown bear Ursus arctos and lynx Lynx lynx is reviewed to determine if sufficient semi-natural habitat exists in the UK for a viable population of any of these species and to assess the potential risks to human safety, livestock and economically valuable wildlife. Public attitudes to the recovery and reintroduction of some other mammals are also briefly reviewed. 2.,The large home range sizes and low population densities of large carnivores mean that the Scottish Highlands is the only UK region with the potential to support a viable population. Human population density is also lower in the Highlands and the density of wild ungulate prey higher than in many parts of Europe where large carnivores survive. 3.,Attacks on people have been recorded in Europe for healthy bears and for rabid bears and wolves but there are no reports of attacks by lynx. Bears are more carnivorous in the north of their range than in the south and although wild mammals seldom appear to be important prey serious predation of livestock can occur. Livestock predation is also reported for the wolf and the lynx but they appear to prefer wild prey if available. However, mass kills of up to 100 or more sheep are occasionally recorded for wolves. 4.,Attitudes to reintroductions and carnivores generally tend to be favourable amongst the general public, but negative amongst those most likely to be adversely affected. Fears for human safety and significant livestock predation with bears and wolves, respectively, suggest that reintroduction of these species is unlikely to be acceptable in the foreseeable future. Reintroduction of the lynx may be feasible but habitat suitability and potential impact on vulnerable native wildlife need to be assessed. Socio-economic and legal issues also need to be addressed before such a reintroduction is considered. [source]

The demography of introduction pathways, propagule pressure and occurrences of non-native freshwater fish in England

AQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 5 2010
G. H. Copp
Abstract 1.Biological invasion theory predicts that the introduction and establishment of non-native species is positively correlated with propagule pressure. Releases of pet and aquarium fishes to inland waters has a long history; however, few studies have examined the demographic basis of their importation and incidence in the wild. 2.For the 1500 grid squares (10×10,km) that make up England, data on human demographics (population density, numbers of pet shops, garden centres and fish farms), the numbers of non-native freshwater fishes (from consented licences) imported in those grid squares (i.e. propagule pressure), and the reported incidences (in a national database) of non-native fishes in the wild were used to examine spatial relationships between the occurrence of non-native fishes and the demographic factors associated with propagule pressure, as well as to test whether the demographic factors are statistically reliable predictors of the incidence of non-native fishes, and as such surrogate estimators of propagule pressure. 3.Principal coordinates of neighbour matrices analyses, used to generate spatially explicit models, and confirmatory factor analysis revealed that spatial distributions of non-native species in England were significantly related to human population density, garden centre density and fish farm density. Human population density and the number of fish imports were identified as the best predictors of propagule pressure. 4.Human population density is an effective surrogate estimator of non-native fish propagule pressure and can be used to predict likely areas of non-native fish introductions. In conjunction with fish movements, where available, human population densities can be used to support biological invasion monitoring programmes across Europe (and perhaps globally) and to inform management decisions as regards the prioritization of areas for the control of non-native fish introductions. © Crown copyright 2010. Reproduced with the permission of her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd. [source]

Abundance and distribution of fish in the lower Mnembo River, Malawi-Mozambique

AFRICAN JOURNAL OF ECOLOGY, Issue 3 2007
Leanda M. Delaney
Abstract Endorheic Lake Chilwa is one of the most productive lakes for fisheries in Africa. High human population densities and agricultural practices in the Chilwa catchment have been linked to observed declines of the annual fish catch in the lake. The Mnembo River is a major inflow into Lake Chilwa which has received little scientific study to date. In 2003/2004, fish diversity, abundance and distribution were monitored monthly at three sites in the Mnembo River. Twelve fish species were collected, a subset of the fourteen fish species present in Lake Chilwa. Although Barbus spp. were the most abundant species sampled in the Mnembo, total biomass was higher for Labeo cylindricus (6709 and 10,434 g, respectively). Total biomass of Pareutropius longifilis (1741 g) and Brycinus imberi (1174 g) were also high in the river. Catches of Barbus and Labeo were highly correlated (r = 0.763). Compared with other inflows into Lake Chilwa (Likangala and Domasi), the Mnembo River appears to be less adversely influenced by human populations, with high abundance of Barbus and strong presence of the riverine species Labeo, Pareutropius and Brycinus. Résumé Le lac Chilwa est endorhéique. C'est un des lacs les plus productifs d'Afrique. De fortes densités de population humaine et les pratiques agricoles du bassin de Chilwa sont liées au déclin des prises annuelles de poisson que l'on a observé. La rivière Mnembo est un des affluents majeurs du lac; elle a fait l'objet de peu d'études scientifiques jusqu'à présent. En 2003,2004, on a surveillé la diversité, l'abondance et la distribution du poisson de façon régulière, chaque mois, à trois endroits le long de la Mnembo. On a récolté douze espèces de poissons, une partie des quatorze espèces trouvées dans le lac Chilwa. Même si Barbus spp. était l'espèce la plus abondante récoltée dans la Mnembo, la biomasse totale était plus forte pour Labeo cylindricus (6.709 g et 10.434 g, respectivement). La biomasse totale de Pareutropius longifilis (1.741 g) et deBrycinus imberi (1.174 g) était aussi élevée dans la rivière. Les prises de Barbus et de Labeoétaient en forte corrélation (r = 0,763). Comparée aux autres affluents du lac Chilwa (Likangala et Domasi), la Mnembo semble moins souffrir de l'influence des populations humaines, avec la grande abondance de Barbus et une présence affirmée des espèces de rivage que sont Labeo, Pareutropius et Brycinus. [source]

Grassland diversity related to the Late Iron Age human population density

JOURNAL OF ECOLOGY, Issue 3 2007
MEELIS PÄRTEL
Summary 1Species-rich semi-natural grasslands in Europe developed during prehistoric times and have endured due to human activity. At the same time, intensive grassland management or changes in land use may result in species extinction. As a consequence, plant diversity in semi-natural calcareous grasslands may be related to both historical and current human population density. 2We hypothesize that current vascular plant diversity in semi-natural calcareous grasslands is positively correlated with the Late Iron Age (c. 800,1000 years ago) density of human settlements (indicated by Late Iron Age fortresses and villages) due to enhancement of grassland extent and species dispersal, and negatively correlated with current human population density due to habitat loss and deterioration. 3We described the size of the community vascular plant species pool, species richness per 1 m2 and the relative richness (richness divided by the size of the species pool) in 45 thin soil, calcareous (alvar) grasslands in Estonia. In addition to historical and current human population density we considered simultaneously the effects of grassland area, connectivity to other alvar grasslands, elevation above sea level (indicating grassland age), soil pH, soil N, soil P, soil depth, soil depth heterogeneity, geographical east,west gradient, precipitation and spatial autocorrelation. 4Both the size of the community species pool and the species richness are significantly correlated with the Late Iron Age human population density. In addition, species richness was unimodally related to the current human population density. The relative richness (species ,packing density') was highest in the intermediate current human population densities, indicative of moderate land-use intensity. 5Community species pool size decreased non-linearly with increasing soil N, and was highest at intermediate elevation. Small-scale richness was greater when sites were well connected and when the elevation was intermediate. Spatial autocorrelation was also significant for both species pool size and small-scale richness. 6In summary, human land-use legacy from prehistoric times is an important aspect in plant ecology, which could be an important contributor to the current variation in biodiversity. [source]

The demography of introduction pathways, propagule pressure and occurrences of non-native freshwater fish in England

Emerging and poorly known viral inflammatory eye diseases

ACTA OPHTHALMOLOGICA, Issue 2009
M KHAIRALLAH
Arthropod vector borne diseases are among the most important emergent infections. They include a wide variety of bacterial, viral, and parasitic diseases that are transmitted to humans by the bite of mosquito, tick, or other arthropod. Most of them are prevalent in tropical and subtropical areas, but they tend to spread into new regions mainly due to increasing temperatures worldwide, movement of people, increasing human population densities, wider dispersal of competent vectors, and transportation of goods and animals. Numerous arthropod vector borne diseases have been associated with uveitis. Among them, specific viral diseases recently emerged as important causes of uveitis in the developing and developed world. They include West Nile virus (WNV) infection, Rift Valley fever (RVF) , dengue fever (DF), and Chikungunya. These viral diseases have been recently associated with an array of ocular manifestations, including anterior uveitis, retinitis, chorioretinitis, retinal vaculitis, and optic nerve involvement. Proper clinical diagnosis of any of these infectious diseases is based on epidemiological data, history, systemic symptoms and signs, and the pattern of uveitis. The diagnosis is usually confirmed by detection of specific antibody in serum. A systematic ocular examination, showing fairly typical findings, can help establish an early clinical diagnosis of a specific systemic viral infection while serologic testing is pending. Prevention remains the mainstay for control of arthropod vector borne viral diseases. [source]

Disentangling the relative effects of environmental versus human factors on the abundance of native and alien plant species in Mediterranean sandy shores

DIVERSITY AND DISTRIBUTIONS, Issue 4 2010
Marta Carboni
Abstract Aim, Mediterranean coastal sand dunes are characterized by both very stressful environmental conditions and intense human pressure. This work aims to separate the relative contributions of environmental and human factors in determining the presence/abundance of native and alien plant species in such an extreme environment at a regional scale. Location, 250 km of the Italian Tyrrhenian coast (Region Lazio). Methods, We analysed alien and native plant richness and fitted generalized additive models in a multimodel-inference framework with comprehensive randomizations to evaluate the relative contribution of environmental and human correlates in explaining the observed patterns. Results, Native and alien richness are positively correlated, but different variables influence their spatial patterns. For natives, human population density is the most important factor and is negatively related to richness. Numbers of natives are unexpectedly lower in areas with a high proportion of natural land cover (probably attributable to local farming practices) and, to a lesser degree, affected by the movement of the coastline. On the other hand, alien species richness is strongly related to climatic factors, and more aliens are found in sectors with high rainfall. Secondarily, alien introductions appear to be related to recent urban sprawl and associated gardening. Main conclusions, Well-adapted native species in a fragile equilibrium with their natural environment are extremely sensitive to human-driven modifications. On the contrary, for more generalist alien species, the availability of limited resources plays a predominant role. [source]

Threats and biodiversity in the mediterranean biome

DIVERSITY AND DISTRIBUTIONS, Issue 2 2009
Emma C. Underwood
ABSTRACT Aim, Global conservation assessments recognize the mediterranean biome as a priority for the conservation of the world's biodiversity. To better direct future conservation efforts in the biome, an improved understanding of the location, magnitude and trend of key threats and their relationship with species of conservation importance is needed. Location, Mediterranean-climate regions in California-Baja California, Chile, South Africa, Australia and the Mediterranean Basin. Methods, We undertook a systematic, pan-regional assessment of threats in the mediterranean biome including human population density, urban area and agriculture. To realize the full implications of these threats on mediterranean biodiversity, we examined their relationship with species of conservation concern: threatened mammals at the global scale and threatened plants at the subecoregional scale in California, USA. Results, Across the biome, population density and urban area increased by 13% and agriculture by 1% between 1990 and 2000. Both population density and urban area were greatest in California-Baja California and least in Australia while, in contrast, agriculture was greatest in Australia and least in California-Baja California. In all regions lowlands were most affected by the threats analysed, with the exception of population density in the Chilean matorral. Threatened species richness had a significant positive correlation with population density at global and subecoregional scales, while threatened species were found to increase with the amount of urban area and decrease as the amount of natural area and unfragmented core area increased. Main conclusions, Threats to mediterranean biodiversity have increased from 1990 to 2000, although patterns vary both across and within the five regions. The need for future conservation efforts is further underlined by the positive correlation between species of conservation concern and the increase in population density over the last decade. Challenges to reducing threats extend beyond those analysed to include human,environmental interactions and their synergistic effects, such as urbanization and invasive species and wildfires. [source]

Range-wide patterns of greater sage-grouse persistence

DIVERSITY AND DISTRIBUTIONS, Issue 6 2008
Cameron L. Aldridge
ABSTRACT Aim, Greater sage-grouse (Centrocercus urophasianus), a shrub-steppe obligate species of western North America, currently occupies only half its historical range. Here we examine how broad-scale, long-term trends in landscape condition have affected range contraction. Location, Sagebrush biome of the western USA. Methods, Logistic regression was used to assess persistence and extirpation of greater sage-grouse range based on landscape conditions measured by human population (density and population change), vegetation (percentage of sagebrush habitat), roads (density of and distance to roads), agriculture (cropland, farmland and cattle density), climate (number of severe and extreme droughts) and range periphery. Model predictions were used to identify areas where future extirpations can be expected, while also explaining possible causes of past extirpations. Results, Greater sage-grouse persistence and extirpation were significantly related to sagebrush habitat, cultivated cropland, human population density in 1950, prevalence of severe droughts and historical range periphery. Extirpation of sage-grouse was most likely in areas having at least four persons per square kilometre in 1950, 25% cultivated cropland in 2002 or the presence of three or more severe droughts per decade. In contrast, persistence of sage-grouse was expected when at least 30 km from historical range edge and in habitats containing at least 25% sagebrush cover within 30 km. Extirpation was most often explained (35%) by the combined effects of peripherality (within 30 km of range edge) and lack of sagebrush cover (less than 25% within 30 km). Based on patterns of prior extirpation and model predictions, we predict that 29% of remaining range may be at risk. Main Conclusions, Spatial patterns in greater sage-grouse range contraction can be explained by widely available landscape variables that describe patterns of remaining sagebrush habitat and loss due to cultivation, climatic trends, human population growth and peripherality of populations. However, future range loss may relate less to historical mechanisms and more to recent changes in land use and habitat condition, including energy developments and invasions by non-native species such as cheatgrass (Bromus tectorum) and West Nile virus. In conjunction with local measures of population performance, landscape-scale predictions of future range loss may be useful for prioritizing management and protection. Our results suggest that initial conservation efforts should focus on maintaining large expanses of sagebrush habitat, enhancing quality of existing habitats, and increasing habitat connectivity. [source]

The rich generally get richer, but there are exceptions: Correlations between species richness of native plant species and alien weeds in Mexico

DIVERSITY AND DISTRIBUTIONS, Issue 5-6 2004
Francisco J. Espinosa-García
ABSTRACT Studies on the resistance of communities to plant invasions at different spatial scales have yielded contradictory results that have been attributed to scale-dependent factors. Some of these studies argue either for or against Elton's notion of biotic resistance against invasions through diversity. We studied the correlation between alien weeds and native species, dividing the latter group into weedy and non-weedy species, integrating various factors that influence diversity into an analysis on the scale of the federal states of Mexico. The resulting multiple-regression models for native and alien weed species are robust (adjusted R2 = 0.87 and R2 = 0.69, respectively) and show a strong partial correlation of the number of weed species (native and alien) with the number of non-weed native species. These results agree with studies showing a positive correlation between the number of native and alien species on larger scales. Both models also include human population density as an important predictor variable, but this is more important for alien weeds (, = 0.62) than for native weeds (, = 0.32). In the regression model for native weed species richness, the non-cultivated (fallow) area (, = 0.24) correlated positively with native weed richness. In the model for alien weed species richness, the native weed species richness was an important variable (, = ,0.51), showing a negative partial correlation (rpart = ,0.4). This result is consistent with Elton's biotic resistance hypothesis, suggesting that biotic resistance is scale independent but that this may be masked by other factors that influence the diversity of both weeds and non-weeds. [source]

Contrasting spatial and temporal global change impacts on butterfly species richness during the 20th century

ECOGRAPHY, Issue 6 2006
Peter White
Regional patterns of species richness are often explained by models using temperature or measures habitat suitability. Generally, species richness is positively associated with temperature, and negatively associated with habitat degradation. While these models have been well tested across spatial scales, they have rarely been tested on a temporal scale , in part due to the difficulty in ascertaining accurate historical data at an appropriate resolution. In this study, we compared the results of temporal and spatial models, each incorporating two predictors of species richness: temperature, and human population density (as a surrogate of human-related habitat impacts). We found that the change in species richness from the early to late part of the 20th century was positively correlated with temperature change, and negatively correlated with human population density change. When we compared these results to two spatial models using contemporary and historic data, the spatial effects of temperature on butterfly richness were similar to its temporal effects, while the effect of human population density through time is the opposite of its spatial effect. More generally, the assumption that spatial patterns are equivalent to temporal ones when applying macroecological data to global change is clearly unreliable. [source]

Polybrominated diphenyl ether flame retardants in Chesapeake Bay region, USA, peregrine falcon (Falco peregrinus) eggs: Urban/rural trends,,

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 5 2009
Katherine E. Potter
Abstract A total of 23 peregrine falcon (Falco peregrinus) eggs were obtained between 1993 and 2002 from 13 nests, encompassing 11 locations in the Chesapeake Bay region, USA. When multiple eggs were available from the same clutch, average clutch contaminant concentrations were calculated. An overall median total polybrominated diphenyl ether (PBDE) level of 201 ng/g wet weight was determined for the eggs/clutches examined. The maximum in an individual egg, from an urban highway bridge site, was 354 ng/g. This egg also exhibited the highest BDE 209 burden (48.2 ng/g). Compared to distributions reported in fish and piscivorous birds, falcon eggs were enriched in the more brominated congeners. The BDE congeners 153, 99, and 100 constituted 26.0, 24.8, and 13.1%, respectively, of total PBDEs. In most aquatic species, BDE 47 is the most abundant congener reported; however, it constituted only 4.4% of total PBDEs in the eggs of the present study. The median BDE 209 concentration was 6.3 ng/g. The sum of the octa- to nonabrominated congeners (BDEs 196, 197, 206, 207, and 208) contributed, on average, 14.0% of total PBDEs, exceeding the contribution of BDE 209 (5.9%). Concentrations of polychlorinated biphenyls (PCBs) and 1,1-dichloro-2,2-bis(p -chlorophenyl)ethylene (4,4,-DDE) also were determined in a subset of 16 eggs (collected in 2001,2002 from six nests) and were an order of magnitude greater than the corresponding PBDEs. Median BDE 209 concentrations were significantly correlated (p < 0.01, Spearman R = 0.690) with the human population density of the area surrounding the nest. Total PBDEs, total PCBs, and 4,4,-DDE levels were not correlated to human population density. [source]

Contrasting response of native and alien plant species richness to environmental energy and human impact along alpine elevation gradients

GLOBAL ECOLOGY, Issue 6 2009
Lorenzo Marini
ABSTRACT Aim, We tested whether the species,energy and species,human relationships vary between native and both naturalized and casual alien species richness when other environmental variables had been taken into account. Location, Trento Province, a region (c. 6200 km2) on the southern border of the European Alps (Italy), subdivided into 156 contiguous (c. 37.5 km2) cells and ranging in elevation from 66 to 3769 m. Methods, Data were separated into three subsets, representing richness of natives, naturalized aliens and casual aliens and separately related to temperature, human population and various environmental correlates of plant species diversity. We applied ordinary least squares and simultaneous autoregressive regressions to identify potential contrasting responses of the three plant status subsets and hierarchical partitioning to evaluate the relative importance of the predictor variables. Results, Variation in alien plant species richness along the region was almost entirely explained by temperature and human population density. The relationships were positive but strongly curvilinear. Native species richness was less strongly related to either factor but was positively related to the presence of calcareous bedrock. Native species richness had a decelerating positive relationship with temperature (R2= 55%), whereas naturalized and casual aliens had a positive accelerating relationship explaining 86% and 62% of the variation in richness, respectively. Native species richness had a positive decelerating relationship with population density (R2= 42%), whilst both alien subsets had a positive accelerating relationship. Main conclusions, Alien species richness was higher in areas with the most rich and diverse assemblages of native species. Areas at high altitudes are not especially prone to alien invasion due to energy constraints, low propagule pressure and disturbance, even considering a potential increased in temperature. Thus, if we consider future environmental change, we should expect a stronger response of aliens than natives in the currently warm, urbanized, low-altitude areas than in cold, high-altitude areas where human population density is low. [source]

The coincidence of people and biodiversity in Europe

GLOBAL ECOLOGY, Issue 1 2003
Miguel B. Araújo
ABSTRACT A positive correlation between human population density and species richness has been recorded across the tropics. Here I investigate whether this correlation holds true for Europe. Analyses reveal a positive correlation between human population density and plant (rho = 0.505), mammal (rho = 0.471) and reptile and amphibian (rho = 0.556) species richness. The results are largely concordant with those obtained in similar studies for Africa. However, contrary to previous analyses, the correlation found between people and breeding bird species richness (rho = 0.186) was weak. Of three measures of endemism used, only combined European endemic species richness correlated with human density (rho = 0.437). Richness among combined restricted-range European endemics was not correlated (rho = 0.095) with human density, while richness among all combined restricted-range species was only weakly correlated with human density (rho = 0.167). The results partially support the idea of a correlation between people and biodiversity, although there are some important exceptions. Discussion of possible mechanisms underling the observed patterns is undertaken. [source]

Does designation of protected areas ensure conservation of tree diversity in the Sudanian dry forest of Burkina Faso?

AFRICAN JOURNAL OF ECOLOGY, Issue 2 2010
Souleymane Paré
Abstract The importance of conservation status of the forest (protected versus unprotected) at two sites with differing human population density (high versus low) on the tree diversity of a Sudanian dry forest in Burkina Faso was studied. All woody species were recorded in 127 circular plots (area = 456.16 m2), and density, dominance, frequency, importance value indices and a variety of diversity measures were calculated to assess the species composition, structure and heterogeneity. A total of 69 species, representing 26 families and 52 genera, were found. Combretaceae, Leguminosae subfamily Caesalpinioideae and Rubiaceae were the dominant families. Neither human pressure nor forest conservation status significantly influenced the tree species richness. Stem density and basal area were significantly higher at the site with high population density than otherwise. Fisher's diversity index revealed the unprotected forest at the site with low population density as the most diverse. We identified species with high conservation importance that should be enriched to maintain a viable population size. In conclusion, the current designation of protected areas seems inefficient at ensuring the conservation of tree diversity in the forest reserve. Thus, participatory conservation programme should be initiated. Résumé À deux endroits où la densité de population humaine est différente (forte versus faible), nous avons étudié l'importance du statut de conservation de la forêt (protégée ou non) pour la diversité d'une forêt soudanienne sèche du Burkina Faso. On a enregistré toutes les espèces ligneuses sur 127 parcelles circulaires (superficie = 456,16 m²), et on a calculé la densité, la dominance, les indices de valeurs d'importance value et une variété de mesures de diversité pour évaluer la composition, la structure et l'hétérogénéité des espèces. On a découvert un total de 69 espèces, représentant 26 familles et 52 genres. Les familles dominantes étaient Combretaceae, Leguminosae de la sous-famille Caesalpinioideae, et Rubiaceae. Ni la pression humaine, ni le statut de conservation des forêts n'influençaient significativement la richesse en espèces d'arbres. La densité des troncs et la surface terrière à la base étaient significativement plus élevées sur le site à forte densité de population. L'indice de diversité de Fisher a permis de révéler que la forêt non protégée du site à faible densité de population était la plus diversifiée. Nous avons identifié des espèces de haute valeur de conservation qui devraient être enrichies pour préserver une taille de population viable. En conclusion, la désignation actuelle d'aires protégées semble inefficace pour assurer la conservation de la diversité des arbres dans la réserve forestière. Donc, il faudrait initier un programme de conservation participative. [source]

Grassland diversity related to the Late Iron Age human population density

Assessment Tools for Urban Catchments: Developing Stressor Gradients,

JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 2 2009
David W. Bressler
Abstract:, This is the first in a series of three articles designed to establish empirically defined biological indicators and thresholds for impairment for urbanized catchments, and to describe a process by which the biological condition of waterbodies in urbanized catchments can be applied. This article describes alternative gradients of urbanization for assessing and selecting a nationally applicable biological index (article 2 ,Purcell et al., this issue) and defining the potential of biological communities within a gradient of cumulative stressors (article 3 ,Paul et al. this issue). Gradients were designed to represent the most prominent mosaic of stressors found in urban settings. A primary urban gradient was assembled based on readily obtained information of urbanization to include three broad-scale parameters: percent urban land use/land cover, population density, and road density. This gradient was used as the standard by which alternative urban gradients, which included fine-scale instream chemical and hydrologic parameters, were assessed. Five alternative gradients were developed to provide numerous environmental management options based on availability of data from water program resources. The urban gradients were developed with the intent that they be applied throughout the country; therefore, data from three different regions of the United States (Mid-Atlantic, Midwest, and Pacific Coast) were used to validate the urban gradient model. Our study showed that a relatively straightforward stressor gradient consisting of human population density, road density, and urban land use is useful in providing a framework for developing relevant biological indicators and evaluating the potential of biological communities as a basis for assessing attainment of designated aquatic life use. [source]

A transcriptomic analysis of land-use impacts on the oyster, Crassostrea virginica, in the South Atlantic bight

MOLECULAR ECOLOGY, Issue 11 2009
ROBERT W. CHAPMAN
Abstract Increasing utilization and human population density in the coastal zone is widely believed to place increasing stresses on the resident biota, but confirmation of this belief is somewhat lacking. While we have solid evidence that highly disturbed estuarine systems have dramatic changes in the resident biota (black and white if you will), we lack tools that distinguish the shades of grey. In part, this lack of ability to distinguish shades of grey stems from the analytical tools that have been applied to studies of estuarine systems, and perhaps more important, is the insensitivity of the biological end points that we have used to assess these impacts. In this study, we will present data on the phenotypic adjustments as measured by transcriptomic signatures of a resilient organism (oysters) to land-use practices in the surrounding watershed using advanced machine-learning algorithms. We will demonstrate that such an approach can reveal subtle and meaningful shifts in oyster gene expression in response to land use. Further, the data show that gill tissues are far more responsive and provide superior discrimination of land-use classes than hepatopancreas and that transcripts encoding proteins involved in energy production, protein synthesis and basic metabolism are more robust indicators of land use than classic biomarkers such as metallothioneins, GST and cytochrome P-450. [source]

Is the human population a large-scale indicator of the species richness of ground beetles?

ANIMAL CONSERVATION, Issue 5 2010
A. M. Barbosa
Abstract Empirical evidence has often shown a large-scale positive co-occurrence of biodiversity-rich and densely populated regions. This biogeographical pattern has important implications for conservation biology. Previous studies have supported two of the potential mechanisms behind this pattern: the distributions of biodiversity and of human beings tend to match climatic patterns, and human beings have settled in regions of higher habitat heterogeneity or they may have increased it. There has been little testing and evidence for an artefactual explanation: more populated regions may show more species only because of a more thorough sampling. Using a new country-wide dataset, we tested whether the human population density correlates with the species richness of ground beetles in Italy's regions, provinces and 10 × 10 km (UTM) grid cells. As expected, the observed and estimated (Chao index) number of species increases significantly with increasing human population density for regions, while there is no significant variation for provinces. But this is not the case when controlling for sampling effort. Variations in observed and estimated species richness are primarily associated with the available number of records, which is in turn well correlated with human population size. These results were confirmed for endemic and widespread species richness. At the UTM level, when controlling for sampling effort and area, there was a significant positive correlation between the total/widespread species richness and variation in the human population size, while the correlation was negative for endemic species. We found no significant role of habitat heterogeneity in the above relationships. The available distributional data of Carabidae in Italy suggest (1) that the species richness of bio-indicators may not be a reliable measure for regional biological assessment; (2) that some broad-scale human population,biodiversity correlations can be artefactual. [source]

Effects of human,carnivore conflict on tiger (Panthera tigris) and prey populations in Lao PDR

ANIMAL CONSERVATION, Issue 4 2006
A. Johnson
Abstract Unique to South-east Asia, Lao People's Democratic Republic contains extensive habitat for tigers and their prey within a multiple-use protected area system covering 13% of the country. Although human population density is the lowest in the region, the impact of human occurrence in protected areas on tiger Panthera tigris and prey populations was unknown. We examined the effects of human,carnivore conflict on tiger and prey abundance and distribution in the Nam Et-Phou Louey National Protected Area on the Lao,Vietnam border. We conducted intensive camera-trap sampling of large carnivores and prey at varying levels of human population and monitored carnivore depredation of livestock across the protected area. The relative abundance of large ungulates was low throughout whereas that of small prey was significantly higher where human density was lower. The estimated tiger density for the sample area ranged from 0.2 to 0.7 per 100 km2. Tiger abundance was significantly lower where human population and disturbance were greater. Three factors, commercial poaching associated with livestock grazing followed by prey depletion and competition between large carnivores, are likely responsible for tiger abundance and distribution. Maintaining tigers in the country's protected areas will be dependent on the spatial separation of large carnivores and humans by modifying livestock husbandry practices and enforcing zoning. [source]