scholarly journals Habitat loss in the restricted range of the endemic Ghanaian cichlid Limbochromis robertsi

2019 ◽  
Author(s):  
A. Lamboj ◽  
O. Lucanus ◽  
P. Osei Darko ◽  
J.P Arroyo-Mora ◽  
M Kalacska
Keyword(s):  
Remote Sensing ◽  
Forest Fragmentation ◽  
Habitat Degradation ◽  
Spatial Scales ◽  
Satellite Image ◽  
Freshwater Ecosystems ◽  
Habitat Characteristics ◽  
Small Scale ◽  
Mining Operations ◽  
Continental Scale

ABSTRACTRemote sensing, through satellite image analysis has become an integral and invaluable tool to inform biodiversity conservation and monitoring of habitat degradation and restoration over time. Despite the disproportionately high levels of biodiversity loss in freshwater ecosystems worldwide, ichthyofauna are commonly overlooked in favor of other keystone species. Freshwater fish, as indicators of overall aquatic ecosystem health can also be indicators of larger scale problems within an ecosystem. If endemic and specialized fishes are at risk, the forest and landscape around their habitat is also undergoing change. As a case study demonstrating the utility of multi-temporal, multi-resolution satellite imagery, we examined deforestation and forest fragmentation around the Atewa Forest Reserve, south eastern Ghana. Within small creeks, Limbochromis robertsi, a unique freshwater cichlid with an extremely limited distribution range can be found. Historically, the land cover in the area has undergone substantial deforestation for agriculture and artisanal small-scale mining, primarily for gold. We found deforestation accelerated along with increased forest fragmentation in the 2014 – 2017 period with the majority of the forest loss along the river and creek banks due to small-scale mining operations and increased agriculture. Field visits indicate a decrease in the total population by approximately 90% from the early 1990s to 2018. We illustrate the benefits of determining landscape metrics from local scale remote sensing studies as proxies to assess the decline of endemic species with restricted ranges, whose habitat characteristics and the subsequent pressures they face require detailed analysis at fine temporal and spatial scales not captured by global or continental scale datasets.

scholarly journals Remote Sensing Reveals Lasting Legacies of Land-Use by Small-Scale Foraging Communities in the Southwestern Indian Ocean

2021 ◽  
Vol 9 ◽  
Author(s):  
Dylan S. Davis ◽  
Kristina Douglass
Keyword(s):  
Remote Sensing ◽  
Land Use ◽  
Evolutionary Dynamics ◽  
Environmental Changes ◽  
Spatial Scales ◽  
Small Scale ◽  
Environment Interaction ◽  
Human Environment ◽  
Landscape Modification ◽  
Geochemical Properties

Archaeologists interested in the evolution of anthropogenic landscapes have productively adopted Niche Construction Theory (NCT), in order to assess long-term legacies of human-environment interactions. Applications of NCT have especially been used to elucidate co-evolutionary dynamics in agricultural and pastoral systems. Meanwhile, foraging and/or highly mobile small-scale communities, often thought of as less intensive in terms of land-use than agropastoral economies, have received less theoretical and analytical attention from a landscape perspective. Here we address this lacuna by contributing a novel remote sensing approach for investigating legacies of human-environment interaction on landscapes that have a long history of co-evolution with highly mobile foraging communities. Our study is centered on coastal southwest Madagascar, a region inhabited by foraging and fishing communities for close to two millennia. Despite significant environmental changes in southwest Madagascar’s environment following human settlement, including a wave of faunal extinctions, little is known about the scale, pace and nature of anthropogenic landscape modification. Archaeological deposits in this area generally bear ephemeral traces of past human activity and do not exhibit readily visible signatures of intensive land-use and landscape modification (e.g., agricultural modifications, monumental architecture, etc.). In this paper we use high-resolution satellite imagery and vegetative indices to reveal a legacy of human-landscape co-evolution by comparing the characteristics – vegetative productivity and geochemical properties – of archaeological sites to those of locations with no documented archaeological materials. Then, we use a random forest (RF) algorithm and spatial statistics to quantify the extent of archaeological activity and use this analysis to contextualize modern-day human-environment dynamics. Our results demonstrate that coastal foraging communities in southwest Madagascar over the past 1,000 years have extensively altered the landscape. Our study thus expands the temporal and spatial scales at which we can evaluate human-environment dynamics on Madagascar, providing new opportunities to study early periods of the island’s human history when mobile foraging communities were the dominant drivers of landscape change.

scholarly journals Downstream Changes in Odonate (Insecta: Odonata) Communities along a Suburban to Urban Gradient: Untangling Natural and Anthropogenic Effects

Insects ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 201
Author(s):  
Wade B. Worthen ◽  
R. Kile Fravel ◽  
Connor P. Horne
Keyword(s):  
Large Scale ◽  
Spatial Scales ◽  
Principal Component ◽  
Open Water ◽  
Information Criteria ◽  
Habitat Characteristics ◽  
Small Scale ◽  
Larval Abundance ◽  
Percent Cover ◽  
Surrounding Landscape

The community structure of lotic odonates (Insecta: Odonata) changes downstream, but it is difficult to untangle natural and anthropogenic causes. We surveyed larvae and adults at 15 sites along the Reedy River in Greenville Co., SC, USA, from sites in forested suburban landscapes through the urban core of the city of Greenville. We used principal component analyses and Akaike information criteria models to describe the relationships between larval and adult community descriptors (abundance, richness, and diversity) and habitat characteristics at several spatial scales, including water chemistry, sediment and detritus, aquatic and streamside vegetation, and the percent cover of landforms in the surrounding landscape. At all scales, larval abundance, richness, and diversity correlated with the amount of detritus. At a small scale, adult indices correlated with the amount of sunlight and streamside vegetation. Zygopteran community composition was nested at a large scale; richness and diversity did not correlate with changes in the landscape but increased downstream. Anisopteran composition was also nested, but richness correlated with the percent cover of field, wetland, and open water in the habitat and was unrelated to downstream site position. Landscape transformation affected anisopterans more than zygopterans by opening habitats that facilitate these generalist heliotherms.

scholarly journals River Flood Detection Using Passive Microwave Remote Sensing in a Data-Scarce Environment: A Case Study for Two River Basins in Malawi

2021 ◽  
Vol 9 ◽  
Author(s):  
Lone C. Mokkenstorm ◽  
Marc J. C. van den Homberg ◽  
Hessel Winsemius ◽  
Andreas Persson
Keyword(s):  
Remote Sensing ◽  
River Discharge ◽  
Spatial Scales ◽  
Time Lag ◽  
Microwave Remote Sensing ◽  
River Basins ◽  
Passive Microwave ◽  
Small Scale ◽  
Passive Microwave Remote Sensing ◽  
The Impact

Detecting and forecasting riverine floods is of paramount importance for adequate disaster risk management and humanitarian response. However, this is challenging in data-scarce and ungauged river basins in developing countries. Satellite remote sensing data offers a cost-effective, low-maintenance alternative to the limited in-situ data when training, parametrizing and operating flood models. Utilizing the signal difference between a measurement (M) and a dry calibration (C) location in Passive Microwave Remote Sensing (PMRS), the resulting rcm index simulates river discharge in the measurement pixel. Whilst this has been demonstrated for several river basins, it is as of yet unknown at what ratio of the spatial scales of the river width vs. the PMRS pixel resolution it remains effective in East-Africa. This study investigates whether PMRS imagery at 37 GHz can be effectively used for flood preparedness in two small-scale basins in Malawi, the Shire and North Rukuru river basins. Two indices were studied: The m index (rcm expressed as a magnitude relative to the average flow) and a new index that uses an additional wet calibration cell: rcmc. Furthermore, the results of both indices were benchmarked against discharge estimates from the Global Flood Awareness System (GloFAS). The results show that the indices have a similar seasonality as the observed discharge. For the Shire River, rcmc had a stronger correlation with discharge (ρ = 0.548) than m (ρ = 0.476), and the former predicts discharge more accurately (R2 = 0.369) than the latter (R2 = 0.245). In Karonga, the indices performed similarly. The indices do not perform well in detecting individual flood events when comparing the signal to a flood impact database. However, these results are sensitive to the threshold used and the impact database quality. The method presented simulated Shire River discharge and detected floods more accurately than GloFAS. It therefore shows potential for river monitoring in data-scarce areas, especially for rivers of a similar or larger spatial scale than the Shire River. Upstream pixels could not directly be used to forecast floods occurring downstream in these specific basins, as the time lag between discharge peaks did not provide sufficient warning time.

scholarly journals A continental measure of urbanness predicts avian response to local urbanization

2019 ◽  
Author(s):  
Corey Thomas Callaghan ◽  
Richard E. Major ◽  
William K. Cornwell ◽  
Ailstair G. B. Poore ◽  
John Wilshire ◽  
...  
Keyword(s):  
Citizen Science ◽  
Spatial Scales ◽  
Environmental Parameters ◽  
Local Scale ◽  
Systematic Sampling ◽  
Small Scale ◽  
Science Data ◽  
Continental Scale ◽  
Specific Variation ◽  
Species Specific

Understanding species-specific relationships with their environment is essential for ecology, biogeography, and conservation biology. Moreover, understanding how these relationships change with spatial scale is critical to mitigating potential threats to biodiversity. But methods which measure inter-specific variation in responses to environmental parameters, generalizable across multiple spatial scales, are lacking. We used broad-scale citizen science data, over a continental scale, integrated with remotely-sensed products, to produce a measure of response to urbanization for a given species at a continental-scale. We then compared these responses to modelled responses to urbanization at a local-scale, based on systematic sampling within a series of small cities. For 49 species which had sufficient data for modelling, we found a significant relationship (R2 = 0.51) between continental-scale urbanness and local-scale urbanness. Our results suggest that continental-scale responses are representative of small-scale responses to urbanization. We also found that relatively few citizen science observations (~250) are necessary for reliable estimates of continental-scale urban scores to predict local-scale response to urbanization. Our method of producing species-specific urban scores is robust and can be generalized to other taxa and other environmental variables with relative ease.

Are frog calls modulated by the environment? An analysis with anuran species from Bolivia

2004 ◽  
Vol 82 (6) ◽  
pp. 880-888 ◽  
Author(s):  
J Bosch ◽  
I De la Riva
Keyword(s):  
Large Scale ◽  
Spatial Scales ◽  
Dominant Frequency ◽  
Taxonomic Position ◽  
Habitat Characteristics ◽  
Acoustic Properties ◽  
Small Scale ◽  
Anuran Species ◽  
Opposite Sex ◽  
Habitat Acoustics

Studies have shown that long-range songs of birds and primates are structurally adapted to local habitat acoustics. The evolution of frog calls, however, seems to be less influenced by habitat. Frogs are extremely dependent on energetically costly acoustic signals, which frequently have to be transmitted over large distances to elicit an encounter with the opposite sex. Different acoustic properties of advertisement calls from 95 Bolivian anuran species were analyzed according to their taxonomic position and the habitat characteristics where each species occurred. The majority of call characteristics, such as diversity of notes, number of pulses per note, or dominant frequency, appear strongly related to taxonomic position. Large-scale habitat characteristics (ecoregion and macrohabitat type) were not related to call characteristics, whereas small-scale habitat (microhabitat) complexity appeared to explain some of the variation in dominant frequency modulation. Species that call in closed microhabitats are more likely to use frequency-modulated calls, which may allow for more efficient sound transmission. To further the understanding of frog-call evolution in response to habitat selection, this and other studies have indicated that studies at finer spatial scales are needed, as well as additional studies restricted to the genus or species level.

Faunal relationships with seagrass habitat structure: a case study using shrimp from the Indo-Pacific

2007 ◽  
Vol 58 (11) ◽  
pp. 1008 ◽  
Author(s):  
Richard K. F. Unsworth ◽  
Sammy De Grave ◽  
Jamaluddin Jompa ◽  
David J. Smith ◽  
James J. Bell
Keyword(s):  
Habitat Complexity ◽  
Positive Impact ◽  
Spatial Scales ◽  
Assemblage Structure ◽  
Habitat Characteristics ◽  
Individual Species ◽  
Small Scale ◽  
Seagrass Habitat ◽  
Generalist Species ◽  
Shrimp Abundance

Caridean shrimp were used as a model group to investigate the effects of seagrass floral habitat complexity on Indo-Pacific fauna. Relationships between shrimp and seagrass habitat characteristics were explored using both multivariate and multiple linear regression modelling approaches. Epifaunal shrimp assemblages were sampled in the Wakatobi Marine National Park, Indonesia. Seagrass habitat complexity had a significant positive impact on shrimp abundance (F3,59 = 17.51, P < 0.001) and species richness (F3,59 = 10.88, P < 0.001), while significantly altering shrimp assemblage structure (ANOSIM global R = 0.397, P < 0.001). In contrast to studies from other bioregions and faunal groups, species diversity and evenness were inversely related to habitat complexity. Changes in shrimp abundance, diversity and assemblage structure with habitat complexity are considered to reflect changes in individual species habitat specialisation. High complexity habitats were dominated by habitat specialists, whereas low complexity seagrass had higher numbers of habitat generalists. Generalist species may be more adapted to the reduced food availability and increased predatory pressures associated with reduced habitat complexity. Although similar patterns were observed at all sites, inter-site differences in shrimp abundance were observed. This indicates that although the present study demonstrates the importance of small-scale changes in seagrass habitat complexity to faunal assemblages, other factors related to larger spatial-scales are also important.

scholarly journals Infrared Quantitative Imaging Technique (IR-QIV) for Remote Sensing of River Flows

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Edwin Alfred Cowen ◽  
Seth Avram Schweitzer
Keyword(s):  
Remote Sensing ◽  
Quantitative Imaging ◽  
Behavior Modeling ◽  
Small Scale ◽  
Time Data ◽  
Continental Scale ◽  
Spectral Bands ◽  
Infrared Spectral ◽  
Near Shore ◽  
Dynamics Models

Stage and discharge are some of the oldest measurements in environmental fluid mechanics and are vital in forecasting water supply and flood safety. These measurements are traditionally manpower intensive, hence expensive, and dangerous under high flow conditions. Considering climate change and the planet’s increasing population there is a critical need for better, more accurate, and frequent, in space and time, data for model and forecast guidance. This need spans monitoring small-scale turbulent processes to calibrating and nudging continental scale river dynamics models. Driven by applications from river gaging networks to fish behavior modeling to flood and erosion forecasting, and more generally, the near-shore environment of lakes, estuaries and the coasts, remote sensing with quantitative imaging tools is a rapidly expanding field. Such tools can be deployed from fixed platforms, drones, planes and satellites with valuable information contained within the visible to infrared spectral bands.

Small-scale effect of intertidal seagrass (Zostera muelleri) on meiofaunal abundance, biomass, and nematode community structure

2010 ◽  
Vol 91 (3) ◽  
pp. 579-591 ◽  
Author(s):  
Daniel Leduc ◽  
P. Keith Probert
Keyword(s):  
Organic Matter ◽  
Community Structure ◽  
Spatial Scales ◽  
Nematode Community ◽  
Habitat Characteristics ◽  
Small Scale ◽  
Seagrass Beds ◽  
Seagrass Bed ◽  
Feeding Groups ◽  
The Impact

Seagrass beds are common features of coastal ecosystems worldwide, and their associated infauna are often more productive and diverse than in unvegetated habitats. Little is known, however, about the ecology of meiofaunal communities living in seagrass sediments. We compared the abundance and biomass of sediment meiofauna inside and outside an intertidalZostera muelleribed in southern New Zealand to assess the impact of seagrass cover on meiofaunal distribution. Nematode community structure, diversity, and feeding groups were also compared between habitats and sediment depths (0–2, 2–5 and 5–10 cm) to evaluate the effect of seagrass on nematode communities. Meiofaunal biomass was significantly higher inside than outside theZ. muelleribed, but secondary productivity inside the bed is likely to have been limited by the availability of labile organic matter. There were significant differences in nematode community structure between unvegetated, sparsely vegetated, and densely vegetated sites (102 m scale), as well as between sediment depths (cm scale). No significant differences were found in depth-integrated (0–10 cm) nematode diversity between sites, but vertical gradients in diversity differed between vegetated and unvegetated sites. Epistrate feeders were the most common feeding group in unvegetated sediments whereas most feeding groups were common inside the seagrass bed. Findings from this study indicate that seagrass beds can have a marked impact on infaunal structure and function over small spatial scales through their effect on sediment characteristics and organic matter input. Some unexpected trends observed in the present study, i.e. low meiofaunal biomass at the vegetated sites, and lower abundance of copepods inside than outside the seagrass bed, suggest that the nature of seagrass–invertebrate interactions may depend on habitat characteristics and the identity and ecology of species considered.

Application of Remote Sensing in Agriculture

2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Jan Piekarczyk
Keyword(s):  
Remote Sensing ◽  
Precision Agriculture ◽  
Crop Production ◽  
Satellite Images ◽  
Crop Yields ◽  
Spatial Scales ◽  
Strong Relationship ◽  
Physical Parameters ◽  
Agricultural Crop ◽  
Remote Sensing Methods

AbstractWith increasing intensity of agricultural crop production increases the need to obtain information about environmental conditions in which this production takes place. Remote sensing methods, including satellite images, airborne photographs and ground-based spectral measurements can greatly simplify the monitoring of crop development and decision-making to optimize inputs on agricultural production and reduce its harmful effects on the environment. One of the earliest uses of remote sensing in agriculture is crop identification and their acreage estimation. Satellite data acquired for this purpose are necessary to ensure food security and the proper functioning of agricultural markets at national and global scales. Due to strong relationship between plant bio-physical parameters and the amount of electromagnetic radiation reflected (in certain ranges of the spectrum) from plants and then registered by sensors it is possible to predict crop yields. Other applications of remote sensing are intensively developed in the framework of so-called precision agriculture, in small spatial scales including individual fields. Data from ground-based measurements as well as from airborne or satellite images are used to develop yield and soil maps which can be used to determine the doses of irrigation and fertilization and to take decisions on the use of pesticides.

The Determinants of Entrepreneurship Development in Spatial Systems

2017 ◽  
Vol 13 ◽  
pp. 8-24
Author(s):  
Zbigniew Zioło
Keyword(s):  
Spatial Scales ◽  
Institutional Barriers ◽  
Entrepreneurship Development ◽  
Continental Scale ◽  
Spatial Systems ◽  
Business Conditions ◽  
Mutual Relations ◽  
Growth Shape ◽  
Strategic Goal

The processes of technological  progress create new opportunities for economic, social and cultural growth, shape new relations between economic  entities and their environment,  and influence changes in the determinants  of entrepreneurship development.  These processes vary significantly in certain geographic locations, characterised by an enormous  diversity of natural, social, economic and cultural structures. As a consequence, this creates different opportunities  and different conditions for the development of entrepreneurship in certain spatial scales, from the continental scale, through national and regional to local scales. The article presents complex conditions  for the development of entrepreneurship, highlights its limitations resulting from institutional  barriers, and the importance of knowing the mechanisms of mutual relations between spatial systems and the influence of control instruments. The quality of central and local government authorities is of particular significance here, which do not always properly use the mechanisms of rational business support. A serious barrier to the development of entrepreneurship is the low quality of social capital, manifested in a lack of trust in institutional authorities and reluctance to engage in entrepreneurship and business development. The conclusions point out that further research should be developed that will take into account changing business conditions, with a defined strategic goal of raising the quality and standard of living, international competitiveness of the country and products in different market categories.

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