scholarly journals Food plant diversity as broad-scale determinant of avian frugivore richness

2007 ◽  
Vol 274 (1611) ◽  
pp. 799-808 ◽  
Author(s):  
W. Daniel Kissling ◽  
Carsten Rahbek ◽  
Katrin Böhning-Gaese
Keyword(s):  
Species Richness ◽  
Habitat Heterogeneity ◽  
Spatial Scales ◽  
Fruit Size ◽  
Food Plant ◽  
Sub Saharan Africa ◽  
Food Plants ◽  
Close Relationship ◽  
Avian Frugivores ◽  
Sub Saharan

The causes of variation in animal species richness at large spatial scales are intensively debated. Here, we examine whether the diversity of food plants, contemporary climate and energy, or habitat heterogeneity determine species richness patterns of avian frugivores across sub-Saharan Africa. Path models indicate that species richness of Ficus (their fruits being one of the major food resources for frugivores in the tropics) has the strongest direct effect on richness of avian frugivores, whereas the influences of variables related to water–energy and habitat heterogeneity are mainly indirect. The importance of Ficus richness for richness of avian frugivores diminishes with decreasing specialization of birds on fruit eating, but is retained when accounting for spatial autocorrelation. We suggest that a positive relationship between food plant and frugivore species richness could result from niche assembly mechanisms (e.g. coevolutionary adaptations to fruit size, fruit colour or vertical stratification of fruit presentation) or, alternatively, from stochastic speciation–extinction processes. In any case, the close relationship between species richness of Ficus and avian frugivores suggests that figs are keystone resources for animal consumers, even at continental scales.

Processes, Products & Policy: Investigating how drought events are perceived differently across spatial scales

2020 ◽  
Author(s):  
Josie Baulch ◽  
Justin Sheffield ◽  
Jadu Dash
Keyword(s):  
High Resolution ◽  
Spatial Scales ◽  
Sub Saharan Africa ◽  
Scaling Analysis ◽  
Technological Advancement ◽  
High Resolution Data ◽  
New Era ◽  
Drought Assessment ◽  
Satellite Technology ◽  
Sub Saharan

<p>Traditionally, availability of consistent, high quality, high-resolution data for Sub-Saharan Africa (SSA) has been limited, with political barriers, poverty and slow technological advancement all contributing to this issue. Over the past 30 years, a rapid increase in the advancement of satellite technology has led to the new era of ‘big data’, which includes a number of high-resolution, global remote sensing datasets. With an overwhelming amount of data now being downloaded and processed, we need to be sure that the best products are being used, in the most appropriate way, to determine the onset and evolution of extreme hydrological events and to influence policy implementation. This study uses scaling analysis of a number of hydrological and agricultural variables to investigate how spatial resolution influences monitoring of drought events. By studying the 2016/17 drought in Kenya, and assessing the drought footprint at various resolutions, it is evident that the data and its scale largely influences the apparent drought signal. Across all the variables, coarser data showed a significantly reduced drought extent than finer data, with a number of regions appearing to not fall below the drought threshold, when in reality, that area was experiencing drought. The implications of these scale issues could be significant, as drought policies in Kenya are implemented on a county level basis. By understanding the importance of effective scaling between the decision-making scale (policy), the data used for drought assessment (products) and the impacts of drought on the ground (processes), updated drought management and mitigation techniques can be used, with potential to reduce vulnerability to future drought events.</p>

Incorporating local habitat heterogeneity and productivity measures when modelling vertebrate richness

2019 ◽  
Vol 47 (1) ◽  
pp. 7-14 ◽  
Author(s):  
W Justin Cooper ◽  
William J McShea ◽  
David A Luther ◽  
Tavis Forrester
Keyword(s):  
Species Richness ◽  
Habitat Heterogeneity ◽  
Spatial Scales ◽  
Model Performance ◽  
Remotely Sensed ◽  
Habitat Characteristics ◽  
Measurement Scale ◽  
Terrestrial Mammals ◽  
Declining Species ◽  
Monitoring Technologies

SummaryDeclining species richness is a global concern; however, the coarse-scale metrics used at regional or landscape levels might not accurately represent the important habitat characteristics needed to estimate species richness. Currently, there exists a lack of knowledge with regard to the spatial extent necessary to correlate remotely sensed habitat metrics to species richness and animal surveys. We provide a protocol for determining the best scale to use when merging remotely sensed habitat and animal survey data as a step towards improving estimates of vertebrate species richness on broad scales. We test the relative importance of fine-resolution habitat heterogeneity and productivity metrics at multiple spatial scales as predictors of species richness for birds, frogs and mammals using a Bayesian approach and a combination of passive monitoring technologies. Model performance was different for each taxonomic group and dependent on the scale at which habitat heterogeneity and productivity were measured. Optimal scales included a 20-m radius for bats and frogs, an 80-m radius for birds and a 180-m radius for terrestrial mammals. Our results indicate that optimal scales do exist when merging remotely sensed habitat measures with ground-based surveys, but they differ between vertebrate groups. Additionally, the selection of a measurement scale is highly influential to our understanding of the relationships between species richness and habitat characteristics.

scholarly journals PPMaP: Reproducible and Extensible Open-Source Software for Plant Phenological Phase Duration Prediction and Mapping in Sub-Saharan Africa

Agriculture ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 515
Author(s):  
Henri E. Z. Tonnang ◽  
Ritter A. Guimapi ◽  
Anani Y. Bruce ◽  
Dan Makumbi ◽  
Bester T. Mudereri ◽  
...  
Keyword(s):  
Open Source ◽  
Open Source Software ◽  
Field Experiments ◽  
Spatial Scales ◽  
Crop Protection ◽  
Plant Phenology ◽  
Sub Saharan Africa ◽  
Phase Duration ◽  
Sub Saharan ◽  
Landscape Level

Understanding the detailed timing of crop phenology and their variability enhances grain yield and quality by providing precise scheduling of irrigation, fertilization, and crop protection mechanisms. Advances in information and communication technology (ICT) provide a unique opportunity to develop agriculture-related tools that enhance wall-to-wall upscaling of data outputs from point-location data to wide-area spatial scales. Because of the heterogeneity of the worldwide agro-ecological zones where crops are cultivated, it is unproductive to perform plant phenology research without providing means to upscale results to landscape-level while safeguarding field-scale relevance. This paper presents an advanced, reproducible, and open-source software for plant phenology prediction and mapping (PPMaP) that inputs data obtained from multi-location field experiments to derive models for any crop variety. This information can then be applied consecutively at a localized grid within a spatial framework to produce plant phenology predictions at the landscape level. This software runs on the ‘Windows’ platform and supports the development of process-oriented and temperature-driven plant phenology models by intuitively and interactively leading the user through a step-by-step progression to the production of spatial maps for any region of interest in sub-Saharan Africa. Maize (Zea mays L.) was used to demonstrate the robustness, versatility, and high computing efficiency of the resulting modeling outputs of the PPMaP. The framework was implemented in R, providing a flexible and easy-to-use GUI interface. Since this allows for appropriate scaling to the larger spatial domain, the software can effectively be used to determine the spatially explicit length of growing period (LGP) of any variety.

Patterns of species richness in two African-centered, aridity-adapted flightless weevil lineages (Coleoptera: Curculionoidea)

Zootaxa ◽  
2017 ◽  
Vol 4323 (4) ◽  
pp. 593 ◽  
Author(s):  
TAYLOR HICKMAN ◽  
ŞERBAN PROCHEŞ ◽  
SYD RAMDHANI
Keyword(s):  
Species Richness ◽  
Plant Diversity ◽  
Cape Floristic Region ◽  
Sub Saharan Africa ◽  
Eastern Africa ◽  
African Origin ◽  
Succulent Karoo ◽  
Multiple Factors ◽  
The Family ◽  
Sub Saharan

Weevils (Coleoptera: Curculionoidea) represent a remarkable proportion of global biodiversity, yet studies addressing their biogeography remain scarce. The arid parts of sub-Saharan Africa harbour several interesting weevil lineages, the most spectacular being the larger flightless weevils such as the Microcerinae and Brachycerus. Here we map the species richness of these two groups to identify hotspots in their diversity, and make inferences regarding the factors that may have contributed to the observed patterns. Exceptional richness values in both groups are found in southern Africa, and more specifically in the Nama Karoo, which is unremarkable in terms of plant diversity. By comparisons, plant diversity hotspots such as the Succulent Karoo and the Cape Floristic Region appear to have high, but not exceptional, weevil richness. Species richness levels were also high in the grassland and savanna areas of south-eastern Africa, which are not arid. The representation of genera considered here and their closest relatives, suggest an African origin for both lineages. This, combined with recent insights into weevil evolution, raise the possibility that advanced weevils as a whole (the family Curculionidae) originated in Africa and that some of its earliest offshoots survived and subsequently diversified here thanks to multiple factors, relating to climate and plant diversity alike. 

Crossroads Regions

2016 ◽  
Author(s):  
Judith Scheele
Keyword(s):  
Empty Space ◽  
Sub Saharan Africa ◽  
Close Relationship ◽  
Sub Saharan ◽  
And Migration

While the Sahara was long seen as a barrier between sub-Saharan Africa and the Maghrib, it has more recently been described as a bridge: scholarship has thus focused on trans-Saharan trade and migration. Both images exclude internal Saharan production, consumption, and agency: the “desert” remains an empty space that needs to be crossed and whose history is dictated by outside patterns of movement. This article suggests a different approach. It focuses on the circulation of goods, people, and ideas, traces patterns of internal connectivity, and denotes the close relationship among mobility, outside connections, and the making of place.

scholarly journals Using empirical and simulated data to study the influence of environmental heterogeneity on fish species richness in two biogeographic provinces

2014 ◽  
Author(s):  
Philippe Massicotte ◽  
Raphael Proulx ◽  
Gilbert Cabana ◽  
Marco Rodriguez
Keyword(s):  
Species Richness ◽  
Fish Species ◽  
Habitat Heterogeneity ◽  
Environmental Variables ◽  
Spatial Scales ◽  
Simulated Data ◽  
Aquatic Communities ◽  
Modeling Framework ◽  
Heterogeneous Habitats ◽  
Biogeographic Provinces

Loss of species richness in aquatic ecosystems is occurring rapidly and many factors, including habitat heterogeneity, have been suggested to affect the diversity of aquatic communities. We used fish community data (> 200 species) from extensive surveys conducted in two biogeographic provinces (extent > 1000 km) in North America to test the hypothesis that fish species richness is greater in more heterogeneous habitats (grain < 10 km2). Our tests are based on samples collected at nearly 800 stations over a period of five years. Using a set of environmental variables routinely measured by monitoring programs and a random placement model of community assembly, we demonstrate that fish species richness in coastal ecosystems is associated locally with the spatial heterogeneity of environmental variables but not with their magnitude. The observed effect of heterogeneity on species richness was substantially greater than that generated by simulations. Our modeling framework opens avenues for targeted conservation of habitat heterogeneity at broader temporal and spatial scales.

scholarly journals Assessing the Spatial Concentration of Urban Crime: An Insight from Nigeria

2020 ◽  
Author(s):  
Faisal Umar ◽  
Shane D. Johnson ◽  
James A. Cheshire
Keyword(s):  
Spatial Scales ◽  
Secondary Data ◽  
Sub Saharan Africa ◽  
Primary Data ◽  
Crime Victimization ◽  
Crime Concentration ◽  
Household Level ◽  
Law Of Crime Concentration ◽  
The Law ◽  
Sub Saharan

Abstract Objective Research demonstrates that crime is concentrated. This finding is so consistent that David Weisburd refers to this as the “law of crime concentration at place”. However, most research on crime concentration has been conducted in the US or European cities and has used secondary data sources. In this study, we examine whether the law of crime concentration applies in the context of sub-Saharan Africa using primary data. Methods A crime victimization survey was used to collect data in the city of Kaduna (Nigeria). Using these data, the concentration of crime (breaking-and-entering and domestic theft) was examined at the household, street segment, and neighborhood levels. Specifically, variants of a Lorenz curve and the Gini index (GI) were used to examine whether crime concentrates at these different spatial scales and if such concentration reflects anything beyond the spatial distribution of opportunity for these types of offenses. Results Crime was found to concentrate at all spatial scales, and having accounted for expectation, given the distribution of opportunity, crime was most concentrated at the household level, closely followed by street segments. It was relatively less concentrated at the neighborhood level. Conclusion The current study extends previous research in a number of ways. It shows that the law of crime concentration at place applies in a very different context to most previous work. Unlike previous studies, we use primary data collected specifically to test the law, avoiding problems associated with the dark figure of crime. Moreover, the findings persist after accounting for crime opportunity.

Evaluating spatial scales of climate variability in sub-Saharan Africa

2006 ◽  
Vol 88 (3-4) ◽  
pp. 169-177 ◽  
Author(s):  
M. Jury ◽  
H. Rautenbach ◽  
M. Tadross ◽  
A. Philipp
Keyword(s):  
Climate Variability ◽  
Spatial Scales ◽  
Sub Saharan Africa ◽  
Sub Saharan
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