Spatial patterns of a Southern Bell Frog Litoria raniformis population in an agricultural landscape

2007 ◽  
Vol 13 (2) ◽  
pp. 104 ◽  
Author(s):  
Skye Wassens ◽  
David A. Roshier ◽  
Robyn J. Watts ◽  
Alistar I. Robertson
Keyword(s):  
Spatial Patterns ◽  
Spatial Organization ◽  
Agricultural Landscape ◽  
Spatial Scales ◽  
Temporal Changes ◽  
Breeding Period ◽  
Apparent Location ◽  
Ripley’S K ◽  
K Function ◽  
Flooded Areas

We investigated changes in the spatial organization of individuals within a population of endangered Southern Bell Frogs Litoria raniformis over an eight-month period. Our results identified strong temporal changes in both spatial organization and the apparent location of L. raniformis within the study site. Ripley's K Function analyses showed that the position of individuals relative to one another shifted from random immediately after the study site was flooded (p < 0.005), to strongly clustered at spatial scales between 0-1500 m during the peak breeding period (p < 0.005). The majority of flooded areas were dry by April and May and individuals again became aggregated within the remaining waterbodies.

scholarly journals Environmental determinants of haemosporidian parasite prevalence in a declining population of Tree swallows

Parasitology ◽  
2017 ◽  
Vol 145 (7) ◽  
pp. 961-970 ◽  
Author(s):  
Audrey Turcotte ◽  
Marc Bélisle ◽  
Fanie Pelletier ◽  
Dany Garant
Keyword(s):  
Forest Cover ◽  
Agricultural Landscape ◽  
Parasite Prevalence ◽  
Landscape Composition ◽  
Breeding Period ◽  
Tree Swallows ◽  
Environmental Determinants ◽  
Negative Effects ◽  
Haemosporidian Parasite ◽  
Haemosporidian Parasites

AbstractThe prevalence of vector-borne parasites such as haemosporidian species is influenced by several environmental factors. While the negative effects of parasitism on hosts are well documented, these can also be amplified by interactions with environmental stressors, many of which are anthropogenic. Yet, we know little about the possible effects of anthropogenic perturbations on parasite prevalence. The goals of this study were to assess the prevalence and environmental determinants of haemosporidian parasites in a declining population of Tree swallows (Tachycineta bicolor) living in an agricultural landscape in southern Québec, Canada. Overall, a low prevalence and a moderate lineage diversity were identified in both adults and nestlings, confirming that transmission can occur during the breeding period. Anthropic areas, extensive cultures (hayfields and pastures) and forest cover within 500 km of nest boxes, as well as daily temperature fluctuations, were all related to infection by haemosporidian parasites. These findings suggest that anthropogenic alterations of landscape composition can modulate the prevalence of haemosporidian parasites in Tree swallows. Our results represent a baseline for future comparative studies assessing haemosporidian parasite prevalence in human-modified landscapes.

Spatiotemporal Point Pattern Analysis Using Ripley's K Function

2017 ◽  
pp. 155-176
Author(s):  
Alexander Hohl ◽  
Minrui Zheng ◽  
Wenwu Tang ◽  
Eric Delmelle ◽  
Irene Casas
Keyword(s):  
Pattern Analysis ◽  
Point Pattern Analysis ◽  
Point Pattern ◽  
Ripley’S K Function ◽  
Ripley’S K ◽  
Ripley's K ◽  
K Function

scholarly journals The Nine Forms of the French Riviera: Classifying Urban Fabrics from the Pedestrian Perspective.

2017 ◽  
Author(s):  
Alessandro Araldi ◽  
Giovanni Fusco
Keyword(s):  
Spatial Patterns ◽  
Urban Space ◽  
Metropolitan Area ◽  
Urban Form ◽  
Spatial Organization ◽  
Spatial Relations ◽  
Urban Morphology ◽  
Urban Fabric ◽  
Central Cities ◽  
French Riviera

The Nine Forms of the French Riviera: Classifying Urban Fabrics from the Pedestrian Perspective. Giovanni Fusco, Alessandro Araldi ¹Université Côte-Azur, CNRS, ESPACE - Bd. Eduard Herriot 98. 06200 Nice E-mail: [email protected], [email protected] Keywords: French Riviera, Urban Fabrics, Urban Form Recognition, Geoprocessing Conference topics and scale: Tools of analysis in urban morphology     Recent metropolitan growth produces new kinds of urban fabric, revealing different logics in the organization of urban space, but coexisting with more traditional urban fabrics in central cities and older suburbs. Having an overall view of the spatial patterns of urban fabrics in a vast metropolitan area is paramount for understanding the emerging spatial organization of the contemporary metropolis. The French Riviera is a polycentric metropolitan area of more than 1200 km2 structured around the old coastal cities of Nice, Cannes, Antibes and Monaco. XIX century and early XX century urban growth is now complemented by modern developments and more recent suburban areas. A large-scale analysis of urban fabrics can only be carried out through a new geoprocessing protocol, combining indicators of spatial relations within urban fabrics, geo-statistical analysis and Bayesian data-mining. Applied to the French Riviera, nine families of urban fabrics are identified and correlated to the historical periods of their production. Central cities are thus characterized by the combination of different families of pre-modern, dense, continuous built-up fabrics, as well as by modern discontinuous forms. More interestingly, fringe-belts in Nice and Cannes, as well as the techno-park of Sophia-Antipolis, combine a spinal cord of connective artificial fabrics having sparse specialized buildings, with the already mentioned discontinuous fabrics of modern urbanism. Further forms are identified in the suburban and “rurban” spaces around central cities. The proposed geoprocessing procedure is not intended to supersede traditional expert-base analysis of urban fabric. Rather, it should be considered as a complementary tool for large urban space analysis and as an input for studying urban form relation to socioeconomic phenomena. References   Conzen, M.R.G (1960) Alnwick, Northumberland : A Study in Town-Planning Analysis. (London, George Philip). Conzen, M.P. (2009) “How cities internalize their former urban fringe. A cross-cultural comparison”. Urban Morphology, 13, 29-54. Graff, P. (2014) Une ville d’exception. Nice, dans l'effervescence du 20° siècle. (Serre, Nice). Yamada I., Thill J.C. (2010) “Local indicators of network-constrained clusters in spatial patterns represented by a link attribute.” Annals of the Association of American Geographers, 100(2), 269-285. Levy, A. (1999) “Urban morphology and the problem of modern urban fabric : some questions for research”, Urban Morphology, 3(2), 79-85. Okabe, A. Sugihara, K. (2012) Spatial Analysis along Networks: Statistical and Computational Methods. (John Wiley and sons, UK).

scholarly journals Multi-scale data on intertidal macrobenthic biodiversity and environmental features in three New Zealand harbours

2019 ◽  
Author(s):  
Casper Kraan ◽  
Barry L. Greenfield ◽  
Simon F. Thrush
Keyword(s):  
New Zealand ◽  
Environmental Variables ◽  
Spatial Organization ◽  
Spatial Scales ◽  
Species Distributions ◽  
Sediment Grain Size ◽  
High Resolution Data ◽  
Multi Scale ◽  
Grain Size Distributions ◽  
Patterns And Processes

Abstract. Understanding how the plants and animals that live in the seafloor vary in their spatial patterns of diversity and abundance is fundamental to gaining insight in the role of biodiversity in maintaining ecosystem functioning in coastal ecosystems, as well as advancing the modelling of species distributions under realistic assumptions. Yet, it is virtually unknown how the relationships between abundance patterns and different biotic and environmental processes change depending on spatial scales, which is mainly due to a lack of data. Within the project Spatial Organization of Species Distributions: Hierarchical and Scale-Dependent Patterns and Processes in Coastal Seascapes at the National Institute for Water and Atmospheric Research (NIWA) in New Zealand we collected multi-scale and high-resolution data on macrobenthic biodiversity. We found 146 species, i.e. bivalves, polychaetes and crustaceans (> 500 μm) that live hidden in marine sandflats, and collected point measurements of important environmental variables (sediment grain-size distributions, chlorophyll a concentration, and visible sandflat parameters) in three large intertidal Harbours (Kaipara, Tauranga and Manukau). In each Harbour we sampled 400 points for macrobenthic community composition and abundances, as well as the full set of environmental variables. Using an elaborate sampling design, we were able to cover scales from 30 centimetres to a maximal extent of 1 km. All data and extensive metadata are available from the data publisher PANGAEA via the persistent identifier https://doi.org/10.1594/PANGAEA.903448.

scholarly journals Are Distribution Patterns Correlated with Plant Traits?

2021 ◽  
Author(s):  
◽  
Benjamin Magana-Rodriguez
Keyword(s):  
Life History ◽  
Leaf Area ◽  
Spatial Patterns ◽  
Life History Traits ◽  
Multiple Scales ◽  
Spatial Scales ◽  
Regional Scale ◽  
Distribution Patterns ◽  
Spatial Arrangement ◽  
Scaling Relationship

<p>The current crisis in loss of biodiversity requires rapid action. Knowledge of species' distribution patterns across scales is of high importance in determining their current status. However, species display many different distribution patterns on multiple scales. A positive relationship between regional (broad-scale) distribution and local abundance (fine-scale) of species is almost a constant pattern in macroecology. Nevertheless interspecific relationships typically contain much scatter. For example, species that possess high local abundance and narrow ranges, or species that are widespread, but locally rare. One way to describe these spatial features of distribution patterns is by analysing the scaling properties of occupancy (e.g., aggregation) in combination with knowledge of the processes that are generating the specific spatial pattern (e.g., reproduction, dispersal, and colonisation). The main goal of my research was to investigate if distribution patterns correlate with plant life-history traits across multiple scales. First, I compared the performance of five empirical models for their ability to describe the scaling relationship of occupancy in two datasets from Molesworth Station, New Zealand. Secondly, I analysed the association between spatial patterns and life history traits at two spatial scales in an assemblage of 46 grassland species in Molesworth Station. The spatial arrangement was quantified using the parameter k from the Negative Binomial Distribution (NBD). Finally, I investigated the same association between spatial patterns and life-history traits across local, regional and national scales, focusing in one of the most diverse families of plant species in New Zealand, the Veronica sect. Hebe (Plantaginaceae). The spatial arrangement was investigated using the mass fractal dimension. Cross-species correlations and phylogenetically independent contrasts were used to investigate the relationships between plant life-history traits and spatial patterns on both data bases. There was no superior occupancy-area model overall for describing the scaling relationship, however the results showed that a variety of occupancy-area models can be fit to different data sets at diverse spatial scales using nonlinear regression. Additionally, here I showed that it is possible to deduce and extrapolate information on occupancy at fine scales from coarse-scale data. For the 46 plantassemblage in Molesworth Station, Specific leaf area (SLA) exhibits a positive association with aggregation in cross-species analysis, while leaf area showed a negative association, and dispersule mass a positive correlation with degree of aggregation in phylogenetic contrast analysis at a local-scale (20 × 20 m resolution). Plant height was the only life-history trait that was associated with degree of aggregation at a regional-scale (100 × 60 mresolution). For the Veronica sect. Hebe dataset, leaf area showed a positive correlation with aggregation while specific leaf area showed a negative correlation with aggregation at a fine local-scale (2.5-60 m resolution). Inflorescence length, breeding system and leaf area showed a negative correlation with degree of aggregation at a regional-scale (2.5-20 km resolution). Height was positively associated with aggregation at national-scale (20-100 km resolution). Although life-history traits showed low predictive ability in explaining aggregation throughout this thesis, there was a general pattern about which processes and traits were important at different scales. At local scales traits related to dispersal and completion such as SLA , leaf area, dispersule mass and the presence of structures in seeds for dispersal, were important; while at regional scales traits related to reproduction such as breeding system, inflorescence length and traits related to dispersal (seed mass) were significant. At national scales only plant height was important in predicting aggregation. Here, it was illustrated how the parameters of these scaling models capture an important aspect of spatial pattern that can be related to other macroecological relationships and the life-history traits of species. This study shows that when several scales of analysis are considered, we can improve our understanding about the factors that are related to species' distribution patterns.</p>

Topographic disequilibrium, landscape dynamics and active tectonics: an example from the Bhutan Himalayas

2021 ◽  
Author(s):  
Martine Simoes ◽  
Timothée Sassolas-Serrayet ◽  
Rodolphe Cattin ◽  
Romain Le Roux-Mallouf ◽  
Matthieu Ferry ◽  
...  
Keyword(s):  
Spatial Organization ◽  
Spatial Scales ◽  
Active Tectonics ◽  
Recent Change ◽  
Climatic Conditions ◽  
Landscape Dynamics ◽  
Drainage Basins ◽  
Equilibrium Conditions ◽  
Longitudinal Band ◽  
Active Tectonic

&lt;p&gt;The quantification of active tectonics from geomorphological and morphometric approaches most often implies that erosion and tectonics have reached a certain balance. Such equilibrium conditions may however be seldom found in nature, in particular because drainage basins may be quite dynamic even though tectonic and climatic conditions remain constant. Here, we document this drainage dynamics from the particular case example of the Bhutan Himalayas. Evidence for out-of-equilibrium morphologies have for long been noticed in Bhutan, from major (&gt; 1 km high) river knickpoints and from the existence of high-altitude low-relief regions within the mountain hinterland. These peculiar morphologies were generally interpreted as representing a recent change in climatic and/or tectonic conditions. To further characterize these morphologies and their dynamics, and from there discuss their origin and meaning, we perform field observations and a detailed quantitative morphometric analysis using Chi plots and Gilbert metrics of drainages over various spatial scales, from major Himalayan rivers to local streams draining the low-relief regions. We first find that the river network is highly dynamic and unstable. Our results emphasize that the morphology of Bhutan does not result from a general wave of incision propagating upstream, as expected from most previous interpretations. Also, the specific spatial organization in which all major knickpoints and low-relief regions are located along a longitudinal band in the Bhutan hinterland, whatever their spatial scale and the dimensions of the associated drainage basins, calls for a common local supporting mechanism most probably related to active tectonic uplift. Our results emphasize the need for a precise documentation of landscape dynamics and disequilibrium over various spatial scales as a first-order step in morpho-tectonic studies of active landscapes.&lt;/p&gt;

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