scholarly journals Information on population trends and biological constraints from bat counts in roost cavities: a 22-year case study of a pipistrelle bats (Pipistrellus pipistrellus Schreber) hibernaculum

2015 ◽  
Vol 42 (1) ◽  
pp. 35 ◽  
Author(s):  
Christian Kerbiriou ◽  
Jean François Julien ◽  
Sophie Monsarrat ◽  
Philippe Lustrat ◽  
Alexandre Haquart ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Population Size ◽  
Spatial Scales ◽  
Population Decline ◽  
Current Trend ◽  
Biodiversity Loss ◽  
Population Trends ◽  
Railway Tunnel ◽  
Biodiversity Indicators ◽  
Pipistrellus Pipistrellus

Context According to the current trend of biodiversity loss, information on population trends at large temporal and spatial scales is necessary. However, well documented animal population dynamics are generally based on intensive protocols requiring animal manipulation, which can be impossible to conduct in species for which conservation is a concern. Aims For many bat species, an alternative approach entails performing an appropriate analysis of counts in roost cavities. Because of managers’ perception of chaotic variations through time, relatively few count monitoring surveys are regularly analysed. Here, we present the analysis of a twenty-two-year survey of a large hibernaculum of pipistrelle bats (Pipistrellus pipistrellus) located in a railway tunnel in Paris, France. Methods We propose that using combinations of population-dynamics modelling using demographic parameters from the literature and statistical analyses helps with identifying the biological and methodological effects underlying the dynamics observed in census analyses. Key results We determined that some of the observed year-to-year variations of population size cannot be explained only by the intrinsic dynamics of the population. In particular, in 1993–94, the population size increased by >40%, which should have implied a massive immigration. This change coincided with the end of the operation of the railway line. After consideration of a drastic trend of population decline (7% year–1), we were able to detect this event and several environmental effects. Specifically, the winter conditions and the temperature in July affected the colony size, presumably because of aggregative behaviour and reproduction success, respectively. Conclusions Emigration–immigration processes might have preponderant effects on population dynamics. In addition, our analysis demonstrated that (1) the study population suffered a large decline, (2) a combination of human disturbance and meteorological variation explains these dynamics and (3) emigration–immigration processes have preponderant effects on the population dynamics. Implications To conduct a meaningful analysis of non-standard time series and provide a source of data for implementing biodiversity indicators, it is necessary to include (1) the local knowledge of the people involved in the field surveys in these analyses (the existence of disturbances and site protections) and (2) meteorological information for the appropriate seasons of the year.

scholarly journals A Call for Conservation Scientists to Empirically Study the Effects of Human Population Policies on Biodiversity Loss

2018 ◽  
Author(s):  
Niki Rust ◽  
Laura Kehoe
Keyword(s):  
Population Dynamics ◽  
Population Size ◽  
Human Population ◽  
Biodiversity Loss ◽  
Female Education ◽  
Population Abundance ◽  
Population Policies ◽  
The World ◽  
Consumption Rates ◽  
Education Initiatives

The world is changing more quickly now than it ever has before, predominantlydue to our large consumption rates and population size. Despite this epoch beingwell-accepted as the “Anthropocene”, it is surprising that there is still a lack ofwillingness by many conservation scientists to engage with the consequencesof human population dynamics on biodiversity. We highlight the importanceof addressing the effects of our population abundance, density and growthrate on conservation and note that environmental organisations are beginningto embrace this problem but the take-up amongst conservation researchers toempirically study their effect on biodiversity is slow. We argue that the lack ofpublished research may partly be because the topic is still considered taboo. Wetherefore urge conservation scientists to direct more of their research efforts onthis issue, particularly to examples that highlight the effects of Population, Healthand Environment (PHE) projects and female education initiatives on biodiversity.

scholarly journals Geoinformation and Cartographic Methods in the Research of the Rural Population Dynamics

2021 ◽  
pp. 20-26
Author(s):  
Natalya Khavanskaya
Keyword(s):  
Population Dynamics ◽  
Spatial Analysis ◽  
Population Size ◽  
Rural Population ◽  
Population Decline ◽  
Population Census ◽  
Rural Settlements ◽  
Automated Mapping ◽  
Eastern Zone ◽  
Volgograd Region

The article deals with the dynamics of the rural population of Volgograd region for 1969–2010. The source materials of the study were archival statistical data on the population size of villages and rural settlements in 1969 and the results of the 2010 All-Russian Population Census. The main purpose of the study has two components: the study of trends in the change of the rural population size and the spatial analysis of villages and rural settlements with different directions of the population dynamics. The main methods were the geoinformation and cartographic method, combining the possibilities of automated mapping according to classified indicators. The results of the work are two maps describing the dynamics of the population of villages and rural settlements. The author used such methods of cartographic representation as the method of cartodiagrams and the method of cartograms based on the classification of the numeric fields of attribute tables. The design and composition of maps was carried out in ArcGis 10.3 geographic information system. The generalized conclusion based on the materials of the work is the prevalence of population decline trends in villages and rural settlements, the strengthening of this trend in the direction from east to west of the region. Natural and geographical areas with a predominance of the tendency for the reduction of the rural population by 50% or more are highlighted: the coast of the rivers Khoper, Buzuluk, Tersa. An increase in the rural population is observed in the districts – suburban areas of Volgograd, the Volga-Ilovlinsky interfluve. The spatial analysis of the rural population dynamics made it possible to distinguish two zones: the western zone, in which the processes of the rural population reduction are the most intense, and the eastern zone, in which, along with a decrease in the population in a number of villages and settlements, its increase is observed.

scholarly journals Population trend inferred from aural surveys for calling anurans in Korea

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5568 ◽  
Author(s):  
Amaël Borzée ◽  
Desiree Andersen ◽  
Yikweon Jang
Keyword(s):  
Population Dynamics ◽  
Population Size ◽  
Population Trends ◽  
High Rate ◽  
Size Difference ◽  
Population Size Estimates ◽  
Key Factor ◽  
Species Dynamics ◽  
The Difference ◽  
The Republic

Amphibian populations fluctuate naturally in size and range and large datasets are required to establish trends in species dynamics. To determine population trends for the endangered Suweon Treefrog (Dryophytes suweonensis), we conducted aural surveys in 2015, 2016, and 2017 at each of 122 sites where the species was known to occur in the Republic of Korea. Despite being based on individual counts, the focus of this study was to establish population trends rather than population size estimates, and we found both environmental and landscape variables to be significant factors. Encroachment was also a key factor that influenced both the decreasing number of calling individuals and the negative population dynamics, represented here by the difference in the number of calling individuals between years. Generally, most sites displayed minimal differences in the number of calling males between years, although there was a large fluctuation in the number of individuals at some sites. Finally, when adjusted for the overall population size difference between years, we found the population size to be decreasing between 2015 and 2017, with a significant decrease in the number of calling individuals at specific sites. High rate of encroachment was the principal explanatory factor behind these marked negative peaks in population dynamics.

scholarly journals Analysis of 220 Years of Floodplain Population Dynamics in the US at Different Spatial Scales

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 141
Author(s):  
Firoza Akhter ◽  
Maurizio Mazzoleni ◽  
Luigia Brandimarte
Keyword(s):  
Population Dynamics ◽  
Large Scale ◽  
Spatial Scales ◽  
National Level ◽  
State Level ◽  
Economic Activities ◽  
Protection Measures ◽  
Management Planning ◽  
The Us ◽  
Over Time

In this study, we explore the long-term trends of floodplain population dynamics at different spatial scales in the contiguous United States (U.S.). We exploit different types of datasets from 1790–2010—i.e., decadal spatial distribution for the population density in the US, global floodplains dataset, large-scale data of flood occurrence and damage, and structural and nonstructural flood protection measures for the US. At the national level, we found that the population initially settled down within the floodplains and then spread across its territory over time. At the state level, we observed that flood damages and national protection measures might have contributed to a learning effect, which in turn, shaped the floodplain population dynamics over time. Finally, at the county level, other socio-economic factors such as local flood insurances, economic activities, and socio-political context may predominantly influence the dynamics. Our study shows that different influencing factors affect floodplain population dynamics at different spatial scales. These facts are crucial for a reliable development and implementation of flood risk management planning.

scholarly journals Cost-efficient factors in local public spending: Detecting relationships between local environments, population size and urban area category

2021 ◽  
pp. 239980832110038
Author(s):  
Hiroki Baba ◽  
Yasushi Asami
Keyword(s):  
Population Size ◽  
Urban Area ◽  
Urban Areas ◽  
Local Governments ◽  
Statistical Significance ◽  
Population Decline ◽  
Public Spending ◽  
Local Environment ◽  
Environment Factors ◽  
Major Factors

This study examines regional differences in local environment factors to better understand the sustainability of local governments indexed by per capita public spending. Under the condition of heterogeneous population size, we examine how factor characteristics differ depending on the spatial context represented by the urban area category. By employing a Cobb–Douglas cost function with congestion effects on public service provision, the estimated factors enable us to articulate major factors and differences in cost-efficiency between urban area categories. We found that statistical significance and even the signatures of local environment factors differ depending on the urban employment area category. Regarding factors such as the ratios of employees in secondary and tertiary industries, these did not tend to be statistically significant in small-sized urban areas, while small-sized cities in large-sized urban areas were likely to gain confidence intervals. Moreover, we did not observe any statistical significance for the ratio of elderly people due to the balance of spending between national and local governments. These findings could contribute to sustainable management of cities in the advent of population decline.

scholarly journals Large numbers of vertebrates began rapid population decline in the late 19th century

2016 ◽  
Vol 113 (49) ◽  
pp. 14079-14084 ◽  
Author(s):  
Haipeng Li ◽  
Jinggong Xiang-Yu ◽  
Guangyi Dai ◽  
Zhili Gu ◽  
Chen Ming ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Size ◽  
Threatened Species ◽  
Driving Forces ◽  
Population Decline ◽  
Cumulative Effect ◽  
Extinction Time ◽  
Time Period ◽  
Large Numbers ◽  
The Difference

Accelerated losses of biodiversity are a hallmark of the current era. Large declines of population size have been widely observed and currently 22,176 species are threatened by extinction. The time at which a threatened species began rapid population decline (RPD) and the rate of RPD provide important clues about the driving forces of population decline and anticipated extinction time. However, these parameters remain unknown for the vast majority of threatened species. Here we analyzed the genetic diversity data of nuclear and mitochondrial loci of 2,764 vertebrate species and found that the mean genetic diversity is lower in threatened species than in related nonthreatened species. Our coalescence-based modeling suggests that in many threatened species the RPD began ∼123 y ago (a 95% confidence interval of 20–260 y). This estimated date coincides with widespread industrialization and a profound change in global living ecosystems over the past two centuries. On average the population size declined by ∼25% every 10 y in a threatened species, and the population size was reduced to ∼5% of its ancestral size. Moreover, the ancestral size of threatened species was, on average, ∼22% smaller than that of nonthreatened species. Because the time period of RPD is short, the cumulative effect of RPD on genetic diversity is still not strong, so that the smaller ancestral size of threatened species may be the major cause of their reduced genetic diversity; RPD explains 24.1–37.5% of the difference in genetic diversity between threatened and nonthreatened species.

Influence of rainfall on population dynamics and survival of a threatened rodent (Pseudomys novaehollandiae) under a drying climate in coastal woodlands of south-eastern Australia

2017 ◽  
Vol 65 (1) ◽  
pp. 60 ◽  
Author(s):  
Mandy Lock ◽  
Barbara A. Wilson
Keyword(s):  
Population Dynamics ◽  
Population Decline ◽  
Resource Depletion ◽  
Mammal Species ◽  
Eastern Australia ◽  
Apparent Decrease ◽  
Mediterranean Systems ◽  
Precipitous Decline ◽  
Breeding Seasons ◽  
Successional Vegetation

In Mediterranean systems, such as south-east Australia, predictions of climate change including lower rainfall and extended drought, threaten vulnerable mammal species. We investigated the relationship between rainfall and population dynamics for a native rodent at risk of extinction, the New Holland mouse (Pseudomys novaehollandiae). In the eastern Otways, the species was significantly influenced by rainfall, exhibiting a population irruption (15–20 individuals ha–1) following six years of above-average rainfall and a precipitous decline to site extinction during subsequent drought. The decline was predominantly related to loss of adults before and during breeding seasons, together with an apparent decrease in juvenile survival. Population abundance was positively correlated with a rainfall lag of 0–9 months. We propose that the response of this omnivore to high rainfall was mediated through increased productivity and that rainfall decline resulted in resource depletion and population decline. Under a drying climate the direct impacts of rainfall decline will continue. However management of other threats may increase the species’ resilience. Burning to provide optimal successional vegetation, protection of refugia, and predator control are priorities. However, burning should be avoided during drought, as the likelihood of local extinctions is substantial.

scholarly journals Developing indicators for European birds

2005 ◽  
Vol 360 (1454) ◽  
pp. 269-288 ◽  
Author(s):  
Richard D Gregory ◽  
Arco van Strien ◽  
Petr Vorisek ◽  
Adriaan W Gmelig Meyling ◽  
David G Noble ◽  
...  
Keyword(s):  
National Level ◽  
Bird Species ◽  
Population Data ◽  
Biodiversity Loss ◽  
Farmland Birds ◽  
Conservation Action ◽  
Breeding Bird ◽  
Field Methods ◽  
Biodiversity Indicators ◽  
Farmland Bird

The global pledge to deliver ‘a significant reduction in the current rate of biodiversity loss by 2010’ is echoed in a number of regional and national level targets. There is broad consensus, however, that in the absence of conservation action, biodiversity will continue to be lost at a rate unprecedented in the recent era. Remarkably, we lack a basic system to measure progress towards these targets and, in particular, we lack standard measures of biodiversity and procedures to construct and assess summary statistics. Here, we develop a simple classification of biodiversity indicators to assist their development and clarify purpose. We use European birds, as example taxa, to show how robust indicators can be constructed and how they can be interpreted. We have developed statistical methods to calculate supranational, multi-species indices using population data from national annual breeding bird surveys in Europe. Skilled volunteers using standardized field methods undertake data collection where methods and survey designs differ slightly across countries. Survey plots tend to be widely distributed at a national level, covering many bird species and habitats with reasonable representation. National species' indices are calculated using log-linear regression, which allows for plot turnover. Supranational species' indices are constructed by combining the national species' indices weighted by national population sizes of each species. Supranational, multi-species indicators are calculated by averaging the resulting indices. We show that common farmland birds in Europe have declined steeply over the last two decades, whereas woodland birds have not. Evidence elsewhere shows that the main driver of farmland bird declines is increased agricultural intensification. We argue that the farmland bird indicator is a useful surrogate for trends in other elements of biodiversity in this habitat.

scholarly journals Population dynamics in northwestern China

2021 ◽  
Author(s):  
Xueyan Yang ◽  
Wanxin Li ◽  
Wen Jing ◽  
Chezhuo Gao ◽  
Rui Li ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Population Structure ◽  
Population Size ◽  
Ethnic Groups ◽  
Northwestern China ◽  
Average Level ◽  
Han Population ◽  
Sex Structure ◽  
Biological Sex

AbstractThis article analyzes the population dynamics in northwestern China from roughly 2010 to 2020. The area’s dynamics showed a slow, stable increase in population size, a stable increase in the population of non-Han ethnic groups, which increased at a more rapidly than the Han population, and population rejuvenation coupled with a population structure that aged. The biological sex structure fluctuated within a balanced range in northwestern China. Urbanization advanced in northwestern China, throughout this period, but the area’s level of urbanization is still significantly lower than the average level of urbanization nationally.

scholarly journals Contrasting responses of above- and belowground diversity to multiple components of land-use intensity

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Gaëtane Le Provost ◽  
Jan Thiele ◽  
Catrin Westphal ◽  
Caterina Penone ◽  
Eric Allan ◽  
...  
Keyword(s):  
Land Use ◽  
Forest Cover ◽  
Spatial Scales ◽  
Biodiversity Loss ◽  
Trophic Levels ◽  
Land Use Intensity ◽  
Trophic Groups ◽  
Multiple Components ◽  
Belowground Diversity ◽  
Landscape Level

AbstractLand-use intensification is a major driver of biodiversity loss. However, understanding how different components of land use drive biodiversity loss requires the investigation of multiple trophic levels across spatial scales. Using data from 150 agricultural grasslands in central Europe, we assess the influence of multiple components of local- and landscape-level land use on more than 4,000 above- and belowground taxa, spanning 20 trophic groups. Plot-level land-use intensity is strongly and negatively associated with aboveground trophic groups, but positively or not associated with belowground trophic groups. Meanwhile, both above- and belowground trophic groups respond to landscape-level land use, but to different drivers: aboveground diversity of grasslands is promoted by diverse surrounding land-cover, while belowground diversity is positively related to a high permanent forest cover in the surrounding landscape. These results highlight a role of landscape-level land use in shaping belowground communities, and suggest that revised agroecosystem management strategies are needed to conserve whole-ecosystem biodiversity.

Sign in / Sign up

Export Citation Format

Share Document