Showing papers on "Occupancy published in 2009"

Energy efficient building environment control strategies using real-time occupancy measurements

Abstract: Current climate control systems often rely on building regulation maximum occupancy numbers for maintaining proper temperatures However, in many situations, there are rooms that are used infrequently, and may be heated or cooled needlessly Having knowledge regarding occupancy and being able to accurately predict usage patterns may allow significant energy-savings by intelligent control of the L-HVAC systems In this paper, we report on the deployment of a wireless camera sensor network for collecting data regarding occupancy in a large multi-function building The system estimates occupancy with an accuracy of 80% Using data collected from this system, we construct multivariate Gaussian and agent based models for predicting user mobility patterns in buildings Using these models, we can predict room usage thereby enabling us to control the HVAC systems in an adaptive manner Our simulations indicate a 14% reduction in HVAC energy usage by having an optimal control strategy based on occupancy estimates and usage patterns

Modeling species occurrence dynamics with multiple states and imperfect detection

Abstract: Recent extensions of occupancy modeling have focused not only on the distribution of species over space, but also on additional state variables (e.g., reproducing or not, with or without disease organisms, relative abundance categories) that provide extra information about occupied sites. These biologist-driven extensions are characterized by ambiguity in both species presence and correct state classification, caused by imperfect detection. We first show the relationships between independently published approaches to the modeling of multistate occupancy. We then extend the pattern-based modeling to the case of sampling over multiple seasons or years in order to estimate state transition probabilities associated with system dynamics. The methodology and its potential for addressing relevant ecological questions are demonstrated using both maximum likelihood (occupancy and successful reproduction dynamics of California Spotted Owl) and Markov chain Monte Carlo estimation approaches (changes in relative abundance of green frogs in Maryland). Just as multistate capture-recapture modeling has revolutionized the study of individual marked animals, we believe that multistate occupancy modeling will dramatically increase our ability to address interesting questions about ecological processes underlying population-level dynamics.

Tigers on trails: occupancy modeling for cluster sampling.

Abstract: Occupancy modeling focuses on inference about the distribution of organisms over space, using temporal or spatial replication to allow inference about the detection process. Inference based on spatial replication strictly requires that replicates be selected randomly and with replacement, but the importance of these design requirements is not well understood. This paper focuses on an increasingly popular sampling design based on spatial replicates that are not selected randomly and that are expected to exhibit Markovian dependence. We develop two new occupancy models for data collected under this sort of design, one based on an underlying Markov model for spatial dependence and the other based on a trap response model with Markovian detections. We then simulated data under the model for Markovian spatial dependence and fit the data to standard occupancy models and to the two new models. Bias of occupancy estimates was substantial for the standard models, smaller for the new trap response model, and negligible for the new spatial process model. We also fit these models to data from a large-scale tiger occupancy survey recently conducted in Karnataka State, southwestern India. In addition to providing evidence of a positive relationship between tiger occupancy and habitat, model selection statistics and estimates strongly supported the use of the model with Markovian spatial dependence. This new model provides another tool for the decomposition of the detection process, which is sometimes needed for proper estimation and which may also permit interesting biological inferences. In addition to designs employing spatial replication, we note the likely existence of temporal Markovian dependence in many designs using temporal replication. The models developed here will be useful either directly, or with minor extensions, for these designs as well. We believe that these new models represent important additions to the suite of modeling tools now available for occupancy estimation in conservation monitoring. More generally, this work represents a contribution to the topic of cluster sampling for situations in which there is a need for specific modeling (e.g., reflecting dependence) for the distribution of the variable(s) of interest among subunits.

Occupancy estimation and the closure assumption

Abstract: Summary 1. Recent advances in occupancy estimation that adjust for imperfect detection have provided substantial improvements over traditional approaches and are receiving considerable use in applied ecology. To estimate and adjust for detectability, occupancy modelling requires multiple surveys at a site and requires the assumption of ‘closure’ between surveys, i.e. no changes in occupancy between surveys. Violations of this assumption could bias parameter estimates; however, little work has assessed model sensitivity to violations of this assumption or how commonly such violations occur in nature. 2. We apply a modelling procedure that can test for closure to two avian point-count data sets in Montana and New Hampshire, USA, that exemplify time-scales at which closure is often assumed. These data sets illustrate different sampling designs that allow testing for closure but are currently rarely employed in field investigations. Using a simulation study, we then evaluate the sensitivity of parameter estimates to changes in site occupancy and evaluate a power analysis developed for sampling designs that is aimed at limiting the likelihood of closure. 3. Application of our approach to point-count data indicates that habitats may frequently be open to changes in site occupancy at time-scales typical of many occupancy investigations, with 71% and 100% of species investigated in Montana and New Hampshire respectively, showing violation of closure across time periods of 3 weeks and 8 days respectively. 4. Simulations suggest that models assuming closure are sensitive to changes in occupancy. Power analyses further suggest that the modelling procedure we apply can effectively test for closure. 5. Synthesis and applications. Our demonstration that sites may be open to changes in site occupancy over time-scales typical of many occupancy investigations, combined with the sensitivity of models to violations of the closure assumption, highlights the importance of properly addressing the closure assumption in both sampling designs and analysis. Furthermore, inappropriately applying closed models could have negative consequences when monitoring rare or declining species for conservation and management decisions, because violations of closure typically lead to overestimates of the probability of occurrence.

Occupancy detection through an extensive environmental sensor network in an open-plan office building

Abstract: Contemporary office buildings commonly experience changes in occupancy patterns and needs due to changes in business practice and personal churns. Hence, it is important to understand and accurately capture the information of such trends for applications in building design and subsequent building operations. Detection of occupant presence has been used extensively in built environments for applications such as demand-controlled ventilation and security, and occupancy profiles are widely used in building simulations. However, the ability to discern the actual number of people in a space is often beyond the scope of current sensing techniques. This paper presents a study to develop algorithms for occupancy number detection based on the analysis of environmental data captured from existing sensors and ambient sensing networks. Both wireless and wired sensor networks are deployed in the Robert L. Preger Intelligent Workplace (IW) at Carnegie Mellon University, comprising six different types of sensors. An average of 80% accuracy on the occupancy number detection was achieved by Hidden Markov Models during testing periods. The findings also offer encouraging possibilities for incorporating the algorithms into building management systems for optimizing energy use while maintaining occupant comfort.

A sensor-utility-network method for estimation of occupancy in buildings

Abstract: We introduce the sensor-utility-network (SUN) method for occupancy estimation in buildings Based on inputs from a variety of sensor measurements, along with historical data regarding building utilization, the SUN estimator produces occupancy estimates through the solution of a receding-horizon convex optimization problem State-of-the-art on-line occupancy algorithms rely on indirect measurements, such as CO 2 levels, or people counting sensors which are subject to significant errors and cost The newly proposed method was evaluated via experiments in an office building environment Estimation accuracy is shown to improve significantly when all available data is incorporated in the estimator In particular, it is found that the average estimation error at the building level is reduced from 70% to 11% using the SUN estimator, when compared to the naive approach that relies solely on flow measurements

Modeling the effects of environmental disturbance on wildlife communities: avian responses to prescribed fire

Abstract: Prescribed fire is a management tool used to reduce fuel loads on public lands in forested areas in the western United States. Identifying the impacts of prescribed fire on bird communities in ponderosa pine (Pinus ponderosa) forests is necessary for providing land management agencies with information regarding the effects of fuel reduction on sensitive, threatened, and migratory bird species. Recent developments in occupancy modeling have established a framework for quantifying the impacts of management practices on wildlife community dynamics. We describe a Bayesian hierarchical model of multi-species occupancy accounting for detection probability, and we demonstrate the model's usefulness for identifying effects of habitat disturbances on wildlife communities. Advantages to using the model include the ability to estimate the effects of environmental impacts on rare or elusive species, the intuitive nature of the modeling, the incorporation of detection probability, the estimation of parameter uncertainty, the flexibility of the model to suit a variety of experimental designs, and the composite estimate of the response that applies to the collection of observed species as opposed to merely a small subset of common species. Our modeling of the impacts of prescribed fire on avian communities in a ponderosa pine forest in Washington indicate that prescribed fire treatments result in increased occupancy rates for several bark-insectivore, cavity-nesting species including a management species of interest, Black-backed Woodpeckers (Picoides arcticus). Three aerial insectivore species, and the ground insectivore, American Robin (Turdus migratorius), also responded positively to prescribed fire, whereas three foliage insectivores and two seed specialists, Clark's Nutcracker (Nucifraga columbiana) and the Pine Siskin (Carduelis pinus), declined following treatments. Land management agencies interested in determining the effects of habitat manipulations on wildlife communities can use these methods to provide guidance for future management activities.

Bayesian Occupancy grid Filter for dynamic environments using prior map knowledge

Abstract: Building a model of the environment is essential for mobile robotics. It allows the robot to reason about its sourroundings and plan actions according to its intentions. To enable safe motion planning it is vital to anticipate object movements. This paper presents an improved formulation for occupancy filtering. Our approach is closely related to the Bayesian Occupancy Filter (BOF) presented in [4]. The basic idea of occupancy filters is to represent the environment as a 2-dimensional grid of cells holding information about their state of occupancy and velocity. To improve the accuracy of predictions, prior knowledge about the motion preferences is used, derived from map data that can be obtained from navigation systems. In combination with a physically accurate transition model, it is possible to estimate the environment dynamics. Experiments show that this yields reliable estimates even for occluded regions.

An investigation of the effect of eco-labeling on office occupancy rates

Abstract: This paper investigates the effect of eco-labeling on the occupancy rates of commercial offices in the United States. The occupancy rates of LEED and ENERGY STAR-labeled offices are compared to a s...

Estimating Brown Hyaena Occupancy Using Baited Camera Traps

Abstract: 2 , occupancy at 1.0 and model-averaged detection probability at 0.1. Using a fish lure increased detection probability to 0.2 and significantly increased encounter rates. We also found that brown hyaenas are more likely to be detected in areas of scrub or woodland rather than grassland. Our results suggest that 13 camera sites would be needed to achieve an occupancy estimate with S.E. of 0.05, and a minimum of 16-34 sampling occasions (with and without the fish lure) should be used in comparable study areas. We conclude that camera trapping is a viable method of estimating brown hyaena occupancy at local and landscape scales and capture-recapture analysis is also possible at a local scale.

Inference About Species Richness and Community Structure Using Species-Specific Occupancy Models in the National Swiss Breeding Bird Survey MHB

Abstract: Species richness is the most widely used biodiversity measure. Virtually always, it cannot be observed but needs to be estimated because some species may be present but remain undetected. This fact is commonly ignored in ecology and management, although it will bias estimates of species richness and related parameters such as occupancy, turnover or extinction rates. We describe a species community modeling strategy based on species-specific models of occurrence, from which estimates of important summaries of community structure, e.g., species richness, occupancy, or measures of similarity among species or sites, are derived by aggregating indicators of occurrence for all species observed in the sample, and for the estimated complement of unobserved species. We use data augmentation for an efficient Bayesian approach to estimation and prediction under this model based on MCMC in WinBUGS. For illustration, we use the Swiss breeding bird survey (MHB) that conducts 2–3 territory-mapping surveys in a systematic sample of 267 1 km2 units on quadrat-specific routes averaging 5.1 km to obtain species-specific estimates of occupancy, and estimates of species richness of all diurnal species free of distorting effects of imperfect detectability. We introduce into our model species-specific covariates relevant to occupancy (elevation, forest cover, route length) and sampling (season, effort). From 1995 to 2004, 185 diurnal breeding bird species were known in Switzerland, and an additional 13 bred 1–3 times since 1900. 134 species were observed during MHB surveys in 254 quadrats surveyed in 2001, and our estimate of 169.9 (95% CI 151–195) therefore appeared sensible. The observed number of species ranged from 4 to 58 (mean 32.8), but with an estimated 0.7–11.2 (mean 2.6) further, unobserved species, the estimated proportion of detected species was 0.48–0.98 (mean 0.91). As is well known, species richness declined at higher elevation and fell above the timberline, and most species showed some preferred elevation. Route length had clear effects on occupancy, suggesting it is a proxy for the size of the effectively sampled area. Detection probability of most species showed clear seasonal patterns and increased with greater survey effort; these are important results for the planning of focused surveys. The main benefit of our model, and its implementation in WinBUGS for which we provide code, is its conceptual simplicity. Species richness is naturally expressed as the sum of occurrences of individual species. Information about species is combined across sites, which yields greater efficiency or may even enable estimation for sites with very few observed species in the first place. At the same time, species detections are clearly segregated into a true state process (occupancy) and an observation process (detection, given occupancy), and covariates can be readily introduced, which provides for efficient introduction of such additional information as well as sharp testing of such relationships.

The consistency and stability of abundance-occupancy relationships in large-scale population dynamics.

Abstract: Summary 1. Abundance‐occupancy relationships comprise some of the most general and well-explored patterns in macro-ecology. The theory governing these relationships predicts that species will exhibit a positive interspecific and intraspecific relationship between regional occupancy and local abundance. Abundance‐occupancy relationships have important implications in using distributional surveys, such as atlases, to understand and document large-scale population dynamics and the consequences of environmental change. A basic need for interpreting such data bases is a better understanding of whether changes in regional occupancy reflect changes in local abundance across species of varying life-history characteristics. 2. Our objective was to test the predictions of the abundance‐occupancy rule using two independent data sets, the New York State Breeding Bird Atlas and the North American Breeding Bird Survey. The New York State Breeding Bird Atlas consists of 5332 25-km 2 survey blocks and is one of the first atlases in the USA to be completed for two time periods (1980‐85 and 2000‐05). The North American Breeding Survey is a large-scale annual survey intended to document the relative abundance and population change of songbirds throughout the USA. 3. We found that regional occupancy was positively correlated with relative abundance across 98 ( β = 0·60 ± 0·11 SE, P < 0·001, R 2 = 0·60) and 85 species ( β = 0·67 ± 0·06 SE, P < 0·001, R 2 = 0·57) in two separate time periods. This relationship proved stable over time and was notably consistent between breeding habitat groups and migratory guilds. 4. Between 1980 and 2005, changes in regional occupancy were highly correlated with long-term abundance trend estimates for 75 species ( β = 5·73 ± 0·24 SE, P < 0·001, R 2 = 0·88). Over a 20-year period, woodland and resident birds showed an increase in occupancy while grassland species showed the greatest decline; these patterns were mirrored by changes in local abundance. 5. Although exceptions existed, we found most changes in occupancy parallel changes in local abundance. These findings support the basic predictions of the abundance‐occupancy rule and demonstrate its consistency and stability in species and groups of varying life-history characteristics.

Patch occupancy in the endangered butterfly Lycaena helle in a fragmented landscape: effects of habitat quality, patch size and isolation

Abstract: While there is agreement that both habitat quality and habitat network characteristics (such as patch size and isolation) contribute to the occupancy of patches by any given species, the relative importance of these factors is under debate. This issue is of fundamental ecological importance, and moreover of special concern for conservation biologists aiming at preserving endangered species. Against this background we investigated patch occupancy in the violet copper Lycaena helle, one of the rarest butterfly species in Central Europe, in the Westerwald area (Rhineland-Palatinate, Western Germany). Occupied (n = 102) differed from vacant (n = 128) patches in altitude, size, connectivity, availability of wind shelter, in the abundance of the larval host-plant, in the abundance of a grass species indicating favorable habitat conditions and in the abundance of nitrophilous plants. Overall, patch occupancy was primarily determined by patch size, connectivity and the abundance of the larval host plant, while all other parameters of habitat quality were of subordinate importance. Therefore, our findings suggest that even for extremely sedentary species such as L. helle habitat networks are decisive and—next to the preservation of habitat quality—need to be an integral part of any conservation management for this species.

Salamander occupancy in headwater stream networks

Abstract: Summary 1. Stream ecosystems exhibit a highly consistent dendritic geometry in which linear habitat units intersect to create a hierarchical network of connected branches. 2. Ecological and life history traits of species living in streams, such as the potential for overland movement, may interact with this architecture to shape patterns of occupancy and response to disturbance. Specifically, large-scale habitat alteration that fragments stream networks and reduces connectivity may reduce the probability a stream is occupied by sensitive species, such as stream salamanders. 3. We collected habitat occupancy data on four species of stream salamanders in first-order (i.e. headwater) streams in undeveloped and urbanised regions of the eastern U.S.A. We then used an information–theoretic approach to test alternative models of salamander occupancy based on a priori predictions of the effects of network configuration, region and salamander life history. 4. Across all four species, we found that streams connected to other first-order streams had higher occupancy than those flowing directly into larger streams and rivers. For three of the four species, occupancy was lower in the urbanised region than in the undeveloped region. 5. These results demonstrate that the spatial configuration of stream networks within protected areas affects the occurrences of stream salamander species. We strongly encourage preservation of network connections between first-order streams in conservation planning and management decisions that may affect stream species.

What factors influence rapid post-fire site re-occupancy? A case study of the endangered Eastern Bristlebird in eastern Australia

Abstract: We quantified the post-fire recovery of the endangered Eastern Bristlebird (Dasyornis brachypterus) at Booderee National Park, south-eastern Australia. Occurrence was recorded on 110 sites a year before, and for 3 years after a major unplanned fire in 2003. Although the Eastern Bristlebird is thought to be sensitive to wildfire, data indicated that the species either persisted continuously on burned sites or returned to previously occupied sites within 2 years. Post-fire site occupancy was associated with several factors: (1) pre-fire site occupancy; (2) vegetation type; (3) spatial heterogeneity in fire and the amount of unburned vegetation surrounding a site; and (4) site-level vegetation structure (e.g. diversity of understorey and midstorey plants). The most likely mechanism underpinning rapid re-occupancy was movement by resident birds to unburned parts elsewhere within their territories. The addition of intensive feral predator baiting within the present study suggests that predation may have a more important effect on populations after unplanned fires than formerly recognised. Our results have significant implications for fire management in areas where the Eastern Bristlebird occurs. Care should be taken with back-burning during unplanned fires and the spatial and temporal arrangement of prescribed fires to ensure unburned vegetation remains as refugia to facilitate bird persistence.

Performance Analysis of Government and Public Buildings Via Post Occupancy Evaluation

Abstract: The government has an important obligation to ensure that the public buildings and facilities should be well managed to maintain building sustainability. Evaluation after occupancy in buildings is vitally needed to ensure that building performance is sustained. Post Occupancy Evaluation (POE) of buildings is of utmost importance in building performance evaluation as it comprises the technique that is used to evaluate whether a building meets the user’s requirement. By using occupants as benchmark in evaluation, the potential of improving the performance of building is enormous. This paper discusses about a research with the broad aim of developing a general guideline for the POE practice specifically for government and public buildings in Malaysia. The entailing objectives are firstly, to review and analyze the government and public building performance, secondly, to determine the occupants’ satisfaction level, and thirdly, to determine the correlation between building performance and occupants’ satisfaction level. The study has revealed that 74% of the aspects of building performance are in high correlation with the occupants’ satisfaction. The study concludes that the proposed guideline of POE is effective, relevant and beneficial to be used by public sector in evaluating the performance of government and public buildings in Malaysia.

Systems and methods for predictive building energy monitoring

Abstract: A system and method for predictive modeling of building energy consumption provides predicted building energy load values which are determined using kernel smoothing of historical building energy load values for a building using defined scaling factors for scaling predictor variables associated with building energy consumption. Predictor variables may include temperature, humidity, windspeed or direction, occupancy, time, day, date, and solar radiation. Scaling factor values may be defined by optimization training using historical building energy load values and measured predictor variable values for a building. Predicted and measured building energy load values are compared to determine if a preset difference threshold has been exceeded, in which case an alert signal or message is generated and transmitted to electronically and/or physically signal a user. The building energy monitoring system may be integrated with a building automation system, or may be operated as a separate system receiving building energy and predictor variable values.

The value of post-occupancy evaluation for building occupants and facility managers

Abstract: User satisfaction studies and measured performance studies reveal that there are significant gaps between the design intent and the performance of buildings and systems over time and occupancy shifts. Whether this gap is due to failures in the design, construction, management or use of buildings is often unclear, user satisfaction studies, augmented by as-built records and measured performance studies to fully understand the performance of buildings and building systems over time. The article introduces the General Services Administration's (GSA) National Environmental Assessment Toolkit (NEAT) field study tools and database and their contributions to advancing the goals of high-performance buildings that meet ongoing occupancy needs and management resources. The NEAT studies undertaken by Carnegie Mellon University's Center for Building Performance GSA have been used to illustrate the value of instrumented post-occupancy evaluation to: promote occupants as sensors and controllers; identify technologies a...

Impact of hurricanes on habitat occupancy and spatial distribution of beach mice

Abstract: Recent increases in hurricane activity along the Gulf of Mexico lend urgency to understanding storm impacts on beach mice (Peromyscus polionotus) that occupy dune systems along this coast in Florida and Alabama. We documented changes in occupancy patterns of the Santa Rosa beach mouse (P. p. leucocephalus) from Hurricane Ivan and examined predictors of habitat use before and after the hurricane. The hurricane removed 68% of frontal dune area occupied by beach mice and only 15% of scrub dune area. Occupancy of frontal dunes by beach mice dropped from 100% before to the hurricane to 60% after the hurricane. Occupancy of scrub habitat was lower than occupancy of frontal dune habitat before the hurricane (,75% occupancy) and did not change with the hurricane. Occupancy of frontal dunes after the hurricane was influenced by percent cover of woody vegetation, dune height, and distance to nearest occupied dune. Probability of occupancy of scrub habitat was positively correlated with individual dune area and amount of surrounding dune habitat before and after the hurricane. Our study supports recent efforts to define scrub dunes as Critical Habitat for beach mice and points to the importance of enhancing dune height and reducing dune isolation in coastal restoration programs.

An Investigation of the Effect of Eco-Labeling on Office Occupancy Rates

Abstract: This paper investigates the effect of eco-labeling on the occupancy rates of commercial offices in the US. The occupancy rates of LEED and Energy Star labeled offices are compared to a sample of non-labeled offices. Using OLS and quantile regression analyses, a significant positive relationship is found between occupancy rate and the eco-label. Controlling for differences in age, height, building class and quality, the results suggest that occupancy rates are approximately 8% higher in LEED labeled offices and 3% higher in Energy Star labeled offices. However, for Energy Star labeled offices effects are concentrated in certain market segments.

Perturbation analysis for patch occupancy dynamics.

Abstract: Perturbation analysis is a powerful tool to study population and community dynamics. This article describes expressions for sensitivity metrics reflecting changes in equilibrium occupancy resulting from small changes in the vital rates of patch occupancy dynamics (i.e., probabilities of local patch colonization and extinction). We illustrate our approach with a case study of occupancy dynamics of Golden Eagle (Aquila chrysaetos) nesting territories. Examination of the hypothesis of system equilibrium suggests that the system satisfies equilibrium conditions. Estimates of vital rates obtained using patch occupancy models are used to estimate equilibrium patch occupancy of eagles. We then compute estimates of sensitivity metrics and discuss their implications for eagle population ecology and management. Finally, we discuss the intuition underlying our sensitivity metrics and then provide examples of ecological questions that can be addressed using perturbation analyses. For instance, the sensitivity metrics lead to predictions about the relative importance of local colonization and local extinction probabilities in influencing equilibrium occupancy for rare and common species.

Relationship between avifaunal occupancy and riparian vegetation in the central great basin (Nevada, U.S.A.)

Abstract: In western North America, riparian vegetation is being lost in response to changes in land use and climate. We examined the relationship between obligate riparian species of songbirds and environmental and riparian habitat factors in three mountain ranges in the central Great Basin (Nevada, U.S.A.). We estimated patterns of occupancy, colonization, and local extinction for three species detected during the breeding seasons of 2001–2006: MacGillivray's Warbler (Oporornis tolmiei), Broad-tailed Hummingbird (Selasphorus platycercus), and Song Sparrow (Melospiza melodia). We used model selection and multimodel inference to identify functional relationships between the occupancy of each species and multiple habitat variables, including the structure and composition of riparian vegetation. Among all years and species, we observed considerable variation in estimates of detection probability. For MacGillivray's Warbler, annual occupancy rates were relatively constant. Occupancy rates for Broad-tailed Hummingbird and Song Sparrow increased during the first 3–4 years of our study and then decreased. Each species experienced its highest rate of local extinction during 2005. Different components of riparian vegetation were good predictors of occupancy, colonization, and local extinction for each species. Typically, elevation and latitude also were strong predictors. Establishing functional relationships between avifauna and vegetation is essential to predicting how land-cover change may affect the occupancy of riparian areas and other habitats for birds. The conservation of breeding birds in riparian areas in the central Great Basin is more likely to succeed if the quality of their understory habitat as well as the canopy is maintained and restored.

Territorial occupancy and breeding performance in a migratory raptor do not follow ideal despotic distribution patterns

Abstract: It has commonly been argued that many territorial species select their breeding sites following an ideal despotic distribution model, in which the most productive, high-quality territories are more frequently occupied Theoretical and empirical studies have shown that this occupancy pattern may have population regulatory consequences, leading to density dependence in heterogeneous habitats During a 9-year research project in a forested area of south-eastern Spain, we tested some of the predictions of the ideal despotic distribution model and the site-dependent population regulation theory in a migratory raptor species, the booted eagle Hieraaetus pennatus Contrary to the predictions of the despotic model, our results showed that the temporal pattern of territorial occupation did not differ from randomness, and that the territory occupancy rate was not significantly related to the reproductive parameters considered At population level, the breeding variables were density independent, suggesting the absence of site-dependent regulation In addition, we were unable to find significant differences in the habitat characteristics between high-quality and low-quality territories, classified according to the criteria of both occupancy frequency and average productivity Overall, our results suggest that booted eagles select their territories at random, probably due to the lack of strong environmental heterogeneity, and that occupancy rate is not a good measure of territory quality for the population studied

The importance of ant‐rich habitats for the persistence of the Wryneck Jynx torquilla on farmland

Abstract: The frequency of territory occupancy is a good indicator of territory quality. We studied territory occupancy in a Swiss population of the Wryneck Jynx torquilla, a declining farmland woodpecker, with the aim of identifying key habitat features for conservation management. Both static and dynamic approaches were applied using data on nest-site occupancy of 100 territories from six successive years. The static approach models the probability of territory occupancy; the dynamic approach estimates territory colonization and extinction. Frequently occupied territories were settled earlier in the season, suggesting that they may be of better quality, and birds settling in these territories had higher breeding success. Probability of territory occupancy increased with the area of old pear orchards and decreased with the area of vegetable cultivation. Both the area of old pear orchards and the presence of conspecifics within a territory were positively related to territory colonization, whereas territory extinction was negatively related to habitat heterogeneity. Old pear orchards were characterized by having both the highest density of ant nests and the greatest amount of bare ground. The latter is likely to facilitate access to ant prey. To ensure persistence of Wryneck populations in farmland, heterogeneous habitat matrices with high ant nest density and bare ground should be promoted. Finally, provision of artificial nesting cavities is likely to enhance territory occupancy. Providing that these key resources are present, Wrynecks are likely to persist even in intensively farmed areas.