scholarly journals Sources and Expectations for Hierarchical Structure in Bird-habitat Associations

The Condor ◽  
2006 ◽  
Vol 108 (1) ◽  
pp. 5-12 ◽  
Author(s):  
William B. Kristan
Keyword(s):  
Hierarchical Structure ◽  
Environmental Variables ◽  
Spatial Scales ◽  
Ground Level ◽  
Threshold Level ◽  
Habitat Associations ◽  
Habitat Characteristics ◽  
Coarse Grained ◽  
Fine Grained ◽  
Bird Habitat

Abstract Hierarchical structure in bird-habitat associations can arise from hierarchical structure in environmental variables and from the scale-dependent responses of birds to habitat. Hierarchical structure in environmental variables is expected to result from interactions between variables that differ in grain size (spatial resolution) and frequency, and should occur commonly. Birds cannot accurately sample habitat characteristics at all spatial scales simultaneously, and the habitat chosen for a given purpose may differ depending on whether a bird samples from high above the ground (which is best for sampling coarse-grained variables) or from ground level (which is best for sampling fine-grained variables). Additionally, birds may exhibit an absolute response to a habitat variable, if it is unsuitable beyond some threshold level, or a relative response, if all available habitat is suitable but some is preferred. Models that can represent hierarchical structure in habitat, as well as hierarchical, scale-dependent responses by birds, should provide researchers the best chance of understanding avian habitat associations.

Scrub–Shrub Bird Habitat Associations at Multiple Spatial Scales in Beaver Meadows in Massachusetts

The Auk ◽  
2009 ◽  
Vol 126 (1) ◽  
pp. 186-197 ◽  
Author(s):  
Richard B. Chandler ◽  
David I. King ◽  
Stephen Destefano
Keyword(s):  
Spatial Scales ◽  
Habitat Associations ◽  
Multiple Spatial Scales ◽  
Bird Habitat

Issues Based on Species Life History and Behavior

2021 ◽  
pp. 89-94
Author(s):  
Joseph A. Veech
Keyword(s):  
Life History ◽  
Habitat Use ◽  
Life Histories ◽  
Radio Telemetry ◽  
Spatial Scales ◽  
Habitat Associations ◽  
Habitat Characteristics ◽  
Habitat Analysis ◽  
The Individual ◽  
And Behavior

Species vary tremendously in their life histories and behavior. The particular life history traits and behavior of the focal species must be considered when designing a study to examine habitat associations. For some species, individuals use different areas (of the landscape or territory) for breeding and foraging. As such, the important characteristics for the foraging and breeding habitats may be different. The dramatically different life stages of some organisms (e.g., amphibians and some insects) often correspond to equally dramatic differences in habitat use between juveniles and adults. For some species, habitat use differs among seasons. Species that are highly mobile and have individuals that move around substantially on a daily or weekly basis are particularly challenging for a habitat analysis. For these species, the most efficient and appropriate study design may be one that tracks individuals (through radio-telemetry or GPS) and analyzes the environmental or habitat characteristics at locations where the individual has stopped, rather than trying to survey for the species in pre-established and insufficiently small survey plots. In addition, individual movement and the issues mentioned above may necessitate that environmental variables are measured and analyzed at multiple spatial scales.

Goals of Characterizing a Species Habitat

2021 ◽  
pp. 73-80
Author(s):  
Joseph A. Veech
Keyword(s):  
Carrying Capacity ◽  
Species Interactions ◽  
Environmental Variables ◽  
Species Coexistence ◽  
Habitat Associations ◽  
Habitat Characteristics ◽  
Habitat Requirements ◽  
Distribution Models ◽  
Habitat Analysis ◽  
Great Utility

There are several reasons for conducting a habitat analysis and identifying the environmental (habitat) characteristics that a species associates with. (1) Knowledge of a species’ habitat requirements is crucial in restoring and managing habitat for the species. (2) Carrying capacity informs us about the potential (or lack thereof) for future population growth based on resource availability. Knowledge of a species’ habitat requirements allows us to interpret the importance of carrying capacity in a habitat-specific way. (3) The study of species interactions and the potential for species coexistence is supported by having knowledge of the habitat of each species under investigation. (4) Habitat preference and selection as eco-evolutionary processes continue to be widely studied by ecologists—interpretation of the results of such studies is best done with knowledge of the species–habitat associations. Such knowledge can also be useful in the design of preference and selection studies. (5) Knowledge of species–habitat associations can also be of great use in selecting the environmental variables to use in species distribution models. All five of these goals point to the great utility of conducting a habitat analysis as a supporting investigation or as a way to obtain knowledge to put to a practical purpose.

Spatial variations in sediment systems

2009 ◽  
Author(s):  
John S. Gray ◽  
Michael Elliott
Keyword(s):  
Spatial Scales ◽  
Coarse Grained ◽  
Anthropogenic Effects ◽  
Individual Species ◽  
Physical Disturbance ◽  
Fine Grained ◽  
The Past ◽  
The Individual ◽  
General Physical

In this chapter the primary emphasis is on spatial scales of disturbances, and we will follow on from our earlier discussions on the mechanisms of competition and predation and the controversy over their importance in controlling species richness. Huston (1994) realized that the effects of competition, predation, and general physical disturbance were similar in that individuals were removed from the assemblage. We now show that there is a need to link these aspects with the tolerances of individual species, for example to determine in which of these cases the organisms are absent because the conditions now fall outside the optimal tolerance ranges. Thus we discuss disturbance as a general phenomenon which includes the effects of any processes that lead to a reduction in numbers of individuals and/or biomass. Disturbance includes physical disturbance as well as biological processes such as the effects of competition and predation on assemblages. The spatial scales covered range from micrometres to many hundreds of kilometres for the effects of bottom trawling, which is now considered to be one of the most serious and damaging threats to sediment habitats and assemblages. Disturbance effects caused by trawling and by pollution are considered in the following chapters. First, it is necessary to consider scale since many new insights have developed in the past few years of research. In the past couple of decades a new branch of ecology, landscape ecology, has developed, devoted to considering patterns over large areas, and a terminology of spatial scales has been defined. Grain is the first level of spatial resolution; it relates to the individual data unit and can be described as fine-grained to coarse-grained. Extent refers to the overall size of the study area. A map of 100 km2 and one of 100 000 km2 differ in extent by a factor of 1000. Grain and extent are illustrated in Fig. 6.1. A third component is lag, which is the betweensample distance. Figure 6.2 summarizes temporal and spatial scales of disturbances (modified from Zajac et al. 1998). The figure shows the main types of disturbances affecting soft-sediment systems, and separates them into natural and anthropogenic effects (see also Chapter 11, which indicates some of the management responses to these effects).

Multi-scale habitat associations of the black-footed rock-wallaby in north-western South Australia

2017 ◽  
Vol 44 (3) ◽  
pp. 207
Author(s):  
Laura Ruykys
Keyword(s):  
Vegetation Type ◽  
Spatial Scales ◽  
Regional Scale ◽  
Habitat Type ◽  
South Australia ◽  
Habitat Associations ◽  
Coarse Grained ◽  
Scale Parameters ◽  
Multi Scale ◽  
Core Areas

Context Research on species’ habitat associations is strengthened if it combines coarse-grained landscape data with finer-scale parameters. However, due to the effort required to measure fine-scale parameters, studies on threatened species that unite these two scales remain relatively rare. Aim This study aimed to undertake a multi-scale analysis of the habitat association of the threatened Petrogale lateralis (MacDonnell Ranges race) in the Anangu Pitjantjatjara Yankunytjatjara (APY) Lands, South Australia. Method Analyses were conducted at four spatial scales: (1) across the Central Ranges IBRA Region (regional scale); (2) on hills in the APY Lands at which P. lateralis is extant and extinct (site scale); (3) at ‘core’ and ‘non-core’ areas within those hills (hillside scale); and (4) at rocky refuges. The maximum entropy approach through the software MaxEnt was used for the analysis at the regional scale. At the remaining scales, fieldwork was used to collect, and regression modelling to analyse, data. Key results At the regional scale, presence was associated with slope and geology. At the site scale, aspect, rock abundance and habitat type are likely to have facilitated animal persistence at extant sites. At the hillside scale, the aspect, vegetation type and rock complexity of core areas are likely to have contributed to their higher use. Size, exposure and accessibility were significant predictors of the use of rocky refuges. Conclusions All four spatial scales yielded novel information on the habitat associations of P. lateralis, supporting previous researchers’ suggestions that habitat modelling should be conducted at multiple spatial scales. Implications The study exemplifies the utility of combining MaxEnt modelling with fieldwork-derived data. The results may have conservation implications for this threatened race, and may also provide a model for other studies of faunal habitat associations.

scholarly journals A NOVEL MULTI GRANULARITY LOCKING SCHEME BASED ON CONCURRENT MULTI -VERSION HIERARCHICAL STRUCTURE

2021 ◽  
Vol 9 (1) ◽  
pp. 932-947
Author(s):  
Ms. Swati, Dr. Shalini Bhaskar Bajaj, Dr. Vivek Jaglan
Keyword(s):  
Hierarchical Structure ◽  
State Of The Art ◽  
Critical Section ◽  
Coarse Grained ◽  
Hierarchical Data ◽  
Trade Off ◽  
Fine Grained ◽  
Locking Mechanism ◽  
Locking Protocol ◽  
Multiple Granularity

We present an efficient locking scheme in a hierarchical data structure. The existing multi-granularity locking mechanism works on two extremes: fine-grained locking through which concurrency is being maximized, and coarse grained locking that is being applied to minimize the locking cost. Between the two extremes, there lies several pare to-optimal options that provide a trade-off between the concurrency that can be attained. In this work, we present a locking technique, Collaborative Granular Version Locking (CGVL) which selects an optimal locking combination to serve locking requests in a hierarchical structure. In CGVL a series of version is being maintained at each granular level which allows the simultaneous execution of read and write operation on the data item. Our study reveals that in order to achieve optimal performance the lock manager explore various locking options by converting certain non-supporting locking modes into supporting locking modes thereby improving the existing compatibility matrix of multiple granularity locking protocol. Our claim is being quantitatively validated by using a Java Sun JDK environment, which shows that our CGVL perform better compared to the state-of-the-art existing MGL methods. In particular, CGVL attains 20% reduction in execution time for the locking operation that are being carried out by considering, the following parameters: i) The number of threads ii) The number of locked object iii) The duration of critical section (CPU Cycles) which significantly supports the achievement of enhanced concurrency  in terms of  the number of concurrent read accesses.

Modeling freshwater mussel distribution in relation to biotic and abiotic habitat variables at multiple spatial scales

2014 ◽  
Vol 71 (10) ◽  
pp. 1483-1497 ◽  
Author(s):  
Ericka E. Hegeman ◽  
Scott W. Miller ◽  
Karen E. Mock
Keyword(s):  
Large Scale ◽  
Freshwater Mussels ◽  
Spatial Scales ◽  
Freshwater Mussel ◽  
Habitat Associations ◽  
Habitat Characteristics ◽  
Physical Habitat ◽  
Lotic Ecosystem ◽  
Unit Scale ◽  
Channel Unit

The habitat requirements of many native freshwater mussels remain unclear despite their imperiled status and ecological importance. To explore scale-specific habitat associations in the three genera of mussels found in the western United States (Anodonta, Gonidea, and Margaritifera) we used a multiscale random forest modeling approach to assess functional habitat parameters throughout a 55 km segment of the upper Middle Fork John Day River in northeastern Oregon. We characterized mussel occurrence and density with respect to the hierarchical, hydrogeomorphic structure by sampling reaches of varying valley confinement and channel units nested within individual reaches. Each genus exhibited unique longitudinal trends and channel unit-use patterns. In particular, the large-scale longitudinal trends in Margaritifera occurrence were associated with hydrogeomorphic characteristics at the reach and channel unit scale, with Margaritifera densities peaking in narrow valley segments and in riffles and runs. At the scale of the channel unit, all mussel genera responded to variation in physical habitat characteristics, particularly those that indicated more stable parts of the channel. Our results suggest that spatial patterns in freshwater mussels are associated with the hierarchical structuring of the lotic ecosystem and may provide guidance to restoration efforts.

scholarly journals The blending region hybrid framework for the simulation of stochastic reaction–diffusion processes

2020 ◽  
Vol 17 (171) ◽  
pp. 20200563
Author(s):  
Christian A. Yates ◽  
Adam George ◽  
Armand Jordana ◽  
Cameron A. Smith ◽  
Andrew B. Duncan ◽  
...  
Keyword(s):  
Diffusion Processes ◽  
Particle Density ◽  
Spatial Scales ◽  
Scale Up ◽  
Computational Cost ◽  
Reaction Diffusion ◽  
Coarse Grained ◽  
Reaction Diffusion Systems ◽  
Fine Grained ◽  
Stochastic Reaction

The simulation of stochastic reaction–diffusion systems using fine-grained representations can become computationally prohibitive when particle numbers become large. If particle numbers are sufficiently high then it may be possible to ignore stochastic fluctuations and use a more efficient coarse-grained simulation approach. Nevertheless, for multiscale systems which exhibit significant spatial variation in concentration, a coarse-grained approach may not be appropriate throughout the simulation domain. Such scenarios suggest a hybrid paradigm in which a computationally cheap, coarse-grained model is coupled to a more expensive, but more detailed fine-grained model, enabling the accurate simulation of the fine-scale dynamics at a reasonable computational cost. In this paper, in order to couple two representations of reaction–diffusion at distinct spatial scales, we allow them to overlap in a ‘blending region’. Both modelling paradigms provide a valid representation of the particle density in this region. From one end of the blending region to the other, control of the implementation of diffusion is passed from one modelling paradigm to another through the use of complementary ‘blending functions’ which scale up or down the contribution of each model to the overall diffusion. We establish the reliability of our novel hybrid paradigm by demonstrating its simulation on four exemplar reaction–diffusion scenarios.

scholarly journals TOPONYMS AS PROXY OF CULTURAL ECOSYSTEM SERVICES: AN EXAMPLE USING CHILEAN MUNICIPALITY NAMES

2018 ◽  
Author(s):  
Gastón O Carvallo ◽  
María J. Escalona
Keyword(s):  
Species Richness ◽  
Ecosystem Services ◽  
Spatial Scales ◽  
Native People ◽  
Coarse Grained ◽  
Cultural Ecosystem Services ◽  
Fine Grained ◽  
Relationship Of ◽  
Human Assessment ◽  
The Relationship

Ecosystem services, the benefits people obtain from ecosystems, have been shown to have a positive relationship with biodiversity. The relationship of cultural ecosystem services (CES) with biodiversity is unclear because CES requires subjective evaluations that are difficult to quantify. Toponyms, the places name, reflect human assessment of the natural environment components, such as species composition, that may be reflexed in the place designation. Therefore, regions with greater biodiversity (e.g. species richness) might be expected to exhibit a greater proportion of toponyms related to biotic elements that places with lower biodiversity. We assessed this prediction using the meaning of 346 municipalities in Chile. Specifically, we analyzed the relationship between species richness and the proportion of toponyms that reference biotic elements at two spatial scales: coarse-grained (regions) and fine-grained (municipalities) scales. Toponyms were categorized according to language origin as being either native (non-Spanish, mainly from Mapuche and Quechua people) or non-native (Spanish). At the coarse-grained scale, we found a positive correlation between species richness and the proportion of toponyms associated with biotic elements (e.g. species names). This relation was maintained when only native language toponyms were considered. At the fine-grained scale, only toponyms with native origin showed a marginal relationship between species richness and the probability that toponyms carry a meaning related to biotic elements. We observed that biodiversity is reflected in the name of places, reinforcing the cultural importance of biodiversity, especially among native people. We propose that toponyms could be incorporated into models used to measure the relative importance of Cultural Ecosystem Services.

Sign in / Sign up

Export Citation Format

Share Document