Occupancy

About: Occupancy is a research topic. Over the lifetime, 2757 publications have been published within this topic receiving 68288 citations.

Evaluating the effects of landscape configuration on site occupancy and movement dynamics of odonates in Iowa

Abstract: Odonates contribute highly to global biodiversity and are considered good indicators of environmental quality, but they are under-studied and quantitative information on their habitat associations is lacking. Our objective was to examine the effects of landscape configuration on site occupancy and movement dynamics of four odonate species in Iowa: Tramea onusta, Epitheca princeps, Pantala flavescens, and Calopteryx maculata. We conducted standardized visual encounter surveys for odonates at 233 public properties in Iowa from 2007 to 2011 and computed landscape variables within a 200, 600 m, and 1 km radius of each surveyed site. Using a robust design occupancy model in Program MARK, we estimated detection probability and site occupancy, site extinction, and site colonization probabilities for each species. We found few significant effects of landscape variables on site occupancy, extinction, or colonization, although landscape variables at 600 m were included in the best model for all species. Detection probability (SE) ranged from 0.30 (0.04) for Pantala flavescens to 0.49 (0.04) for Calopteryx maculata. Our study provides information to aid habitat restoration and management efforts on sites having suitable characteristics in the surrounding landscape and ultimately help conserve odonates.

The Farmed Landscape and the Occupancy Change Process

Abstract: In this paper the relationships between change in farm occupancy and changes in the farmed landscape are examined by reporting on evidence collected from an in-depth resurvey of farm businesses in three study areas in lowland England (West Dorset, East Bedfordshire, and parts of the London Greenbelt). The significance of ‘occupancy events’ in affecting land management and landscape change is indicated. Changes in land area, tenure, business structure, and decisionmaking personnel are assessed as being significant occupancy events which can promote management and landscape alteration. This suggests the need for more sharply focused conservation policy and advice which is tailored to the specific needs of the farm business.

Temporal patch occupancy dynamics of the Siberian flying squirrel in a boreal forest landscape

Abstract: Ability to predict species distribution in a landscape is of crucial importance for natural resource management and species conservation. Therefore, the understanding of species habitat requirements and spatio-temporal dynamics in occurrence is needed. We examined patch occupancy patterns of the Siberian flying squirrel Pteromys volans in northern Finland across a seven year study period. Forest patches dominated by mature spruce (Picea abies) in a study area (375 km 2 ) were surveyed to monitor the presence or absence of the flying squirrel. The patch occupancy pattern was dynamic: about half of the habitat patches were occupied at least once during the study period and more patches were colonised than were abandoned. Patches that were continuously occupied (i.e. occupied during all sample periods) were typically of high quality (based on habitat and landscape characteristics), continuously unoccupied patches were usually of low quality, and intermediate quality patches were occupied intermittently. The variables explaining patch occupancy were similar each year, and a statistical model based on data from the year 2000 also predicted occupancy in 2004 with similar accuracy. However, data from a single survey were inadequate for identifying patches used intermittently by flying squirrels. Despite inconsistent occupancy, these patches may be important for the local persistence of flying squirrels. The dynamic occupancy pattern may thus affect estimates of suitable habitat area and identification of functional patch networks for landscape planning. These results emphasise the need for follow-up studies to better understand population patterns and processes in time.

The effect of industrial noise on owl occupancy in the boreal forest at multiple spatial scales

Abstract: Noise in natural environments can mask important acoustic signals used for animal communication. Owls use vocal communication to attract mates and defend territories, and also rely on acoustic cues to locate their prey. Industrial noise has been shown to negatively affect owl hunting success and reduce foraging efficiency by affecting their ability to detect prey, but it is not known if this results in reduced habitat suitability for owls in areas near industrial noise sources. To determine if owls avoid areas surrounding industrial noise sources in northeastern Alberta and at what scale, we acoustically surveyed for owls at sites with chronic industrial noise, sites with intermittent traffic noise, and sites with no noise. We deployed autonomous recording units at multiple stations within each site to detect territorial individuals vocalizing. Detections of owls were extracted from the recordings using automated species recognition and analyzed using occupancy models at two spatial scales. Barred Owls (Strix varia), Great Horned Owls (Bubo virginianus), and Boreal Owls (Aegolius funereus) were equally likely to occupy both types of noisy sites compared to sites with no noise, indicating that site level occupancy (representing a home range scale) was unaffected by the presence of noise sources on the landscape. On a smaller scale, there was no decline in station level occupancy (representing use of the area surrounding recording stations) at stations with higher noise levels for either of the three owl species. Our study contributes to research on the effects of anthropogenic noise, but suggests the effect on owls is minimal, and unlikely to result in a population change. Effets du bruit industriel sur l'occupation de l'habitat par des hiboux dans la forêt boréale à de multiples échelles spatiales RÉSUMÉ. Le bruit dans l'environnement naturel peut masquer d'importants signaux acoustiques de communication animale. Les hiboux utilisent les communications vocales afin d'attirer un partenaire et pour défendre un territoire, et aussi ils dépendent de leur acuité auditive afin de localiser leurs proies. Il a été démontré que le bruit industriel affecte négativement le succès de chasse des hiboux et diminue l'efficacité d'acquisition de nourriture en affectant leur capacité à détecter les proies, mais on ne sait pas si cela se traduit par une réduction de l'habitat convenable pour les hiboux dans les zones près des sources de bruit industriel. Afin de déterminer si les hiboux évitent les zones entourant les sources de bruit industriel au nord-est de l'Alberta, et à quelle échelle, nous avons échantillonné acoustiquement des sites à bruits industriels chroniques, des sites à bruits intermittents, ainsi que des sites sans bruit. Nous avons déployés des unités autonomes d'enregistrement à plusieurs stations dans chaque site afin de détecter des individus vocalisant dans leur territoire. Les vocalisations de hiboux détectées furent extraites des enregistrements par un système de reconnaissance de l'espèce automatisé et analysé par modèles d'occupation de l'habitat sur deux échelles spatiales. La Chouette Rayée (Strix varia), le Grand-duc d'Amérique (Bubo virginianus), et le Nyctale de Tengmalm (Aegolius funereus) occupaient également les deux types de sites bruyants comparativement aux sites sans bruit, ce qui indique qu'une occupation au niveau du site (échelle du domaine vital) n'a pas été affecté par la présence de bruit au niveau du paysage. À une plus petite échelle, aucune dimunition de l'occupation au niveau de la station (représentant l'utilisation de l'habitat autour des stations d'enregistrements) dans les stations affichant des niveaux de bruit plus élevés pour l'une ou l'autre des trois espèces. Notre étude contribue à la recherche sur les effets du bruit anthropique, mais suggère que l'effet sur les hiboux est minime et qu'il soit peu probable de que ceci contribu à un changement de population.