scholarly journals Foraging Success and Foraging Habitat Use by Cattle Egrets and Little Egrets in the Camargue, France

The Condor ◽  
2001 ◽  
Vol 103 (1) ◽  
pp. 38-44 ◽  
Author(s):  
Katia Lombardini ◽  
Robert E. Bennetts ◽  
Christophe Tourenq
Keyword(s):  
Habitat Use ◽  
Habitat Type ◽  
Foraging Success ◽  
Foraging Habitat ◽  
Mixed Species ◽  
Habitat Types ◽  
Southern France ◽  
Bubulcus Ibis ◽  
Egretta Garzetta ◽  
Selection Of

Abstract We examined habitat use by Little Egrets (Egretta garzetta) and Cattle Egrets (Bubulcus ibis) that nest together in mixed-species colonies in the Camargue of southern France. We explored the relative use of seven habitat types in relation to their availability and tested the hypothesis that selection of habitat types was related to foraging success, with the prediction that increased foraging success in a given habitat corresponded with increased use of that habitat type. Ricefields and other agricultural habitats were used more than expected by Cattle Egrets, an invasive species in southern Europe; whereas Little Egrets, which are native to the Camargue, tended to select natural freshwater marshes and lagoons. Results were consistent with the hypothesis that increasing use of habitats corresponded with higher foraging success for both species. However, when this analysis was restricted to habitats with sufficient numbers of birds to enable estimates of biomass intake, the association was no longer apparent for Little Egrets.

A 28-years-long monitoring study suggests heavy decline and habitat shifts in three populations of a Mediterranean tortoise species

2020 ◽  
Vol 71 (1) ◽  
pp. 21-35
Author(s):  
Lorenzo Rugiero ◽  
Massimo Capula ◽  
Daniele Dendi ◽  
Fabio Petrozzi ◽  
Massimiliano Di Vittorio ◽  
...  
Keyword(s):  
Habitat Use ◽  
Linear Models ◽  
Central Italy ◽  
Habitat Type ◽  
Thermal Ecology ◽  
Ecological Studies ◽  
Monitoring Study ◽  
Testudo Hermanni ◽  
Selection Of

Abstract Long-term ecological studies are important for understanding wild populations’ dynamics and processes and the actual factors that can determine their decline. Here, we report the results of a 28-years-long (1992–2019) monitoring of three distinct populations of a tortoise, Testudo hermanni, in Central Italy, with an emphasis on their population abundance trends and on the eventual variation in their habitat use across years and among the study areas. Samplings were conducted by Visual Encounter Survey (VES) methodology, and using a suite of statistical analyses including correlations and Generalized Linear Models analyses. Our data showed a statistically significant decline in tortoise sightings through time, and concurrently also a variation in habitat use by tortoises. In all the three study areas, we observed a significant increase of tortoise sighting frequency in the habitat type characterized by high (>taller than 200 cm) shrubby and wooded vegetation. Since our analyses revealed no significant change in the habitat type availability by year in each study area, we suggest that T. hermanni was increasingly selecting closed vegetation spots throughout the years. We hypothesize that this observed trend of shift in habitat selection could be due to lowering their body temperatures to prevent overheating. So, the selection of more covered spots would be a thermal ecology adaptive consequence of the ongoing global warming.

Habitat use by female western roe deer (Capreolus capreolus): influence of resource availability on habitat selection in two contrasting years

2010 ◽  
Vol 88 (11) ◽  
pp. 1052-1062 ◽  
Author(s):  
M. Pellerin ◽  
C. Calenge ◽  
S. Saïd ◽  
J.- M. Gaillard ◽  
H. Fritz ◽  
...  
Keyword(s):  
Habitat Selection ◽  
Habitat Use ◽  
Resource Availability ◽  
Roe Deer ◽  
Habitat Type ◽  
Capreolus Capreolus ◽  
Home Ranges ◽  
Distribution Of Resources ◽  
The Relationship ◽  
Selection Of

In most previous studies of habitat selection, the use of a given habitat type is assumed to be directly proportional to its availability. However, the use and (or) the selection of a given habitat may be conditional on the availability of that habitat. We aim here to (i) identify the environmental variables involved in habitat selection, (ii) identify classes of individuals with similar patterns of habitat selection, and (iii) assess whether habitat use changes with changing availability of habitat types, within monthly home ranges of female western roe deer ( Capreolus capreolus (L., 1758)). We found that some females adjust their habitat use according to the distribution of resources within habitats. Females with similar home ranges in terms of resource quantity and quality showed similar patterns of habitat selection. Differences in habitat use between 2 years with contrasting resource availability showed that temporal changes of environmental conditions influenced the pattern of habitat selection by female roe deer. Habitat selection also differed between periods of the life cycle likely because of contrasted energy requirements. This study shows that the relationship between habitat use by herbivores and habitat availability is nonproportional, and that the availability of resources influences use mostly at intermediate values.

Habitat selection by adult female eastern grey kangaroos

2002 ◽  
Vol 29 (5) ◽  
pp. 439 ◽  
Author(s):  
Benjamin D. Moore ◽  
Graeme Coulson ◽  
Sarah Way
Keyword(s):  
Habitat Selection ◽  
Adult Female ◽  
Compositional Analysis ◽  
Home Range Size ◽  
Radio Tracking ◽  
Foraging Habitat ◽  
Habitat Types ◽  
Spring Period ◽  
Night And Day ◽  
Selection Of

We determined patterns of habitat selection in the winter–spring period by adult female eastern grey kangaroos (Macropus giganteus) at Yan Yean Reservoir Catchment near Melbourne, Victoria, during 1994–95. We assessed habitat selection at two levels by radio-tracking 11 adult female kangaroos. The 95% isopleth harmonic mean home-range size (mean = 62.3 ha) was the smallest recorded for female eastern grey kangaroos. No range encompassed all of the habitat types available in the study area, and the mix and rankings of habitats selected at this level varied amongst individuals when compared by compositional analysis with available habitats. Selection of habitats at the within-range level also varied among individuals and differed between night and day for many individuals, but not for the population mean. Individuals selected strongly for good foraging habitat within their ranges. In particular, grassy clearings were used by all individuals and were selected strongly by day, night or at both times.

Habitat use by sympatric female mallards and American black ducks breeding in a forested environment

1994 ◽  
Vol 72 (9) ◽  
pp. 1538-1542 ◽  
Author(s):  
Chris P. Dwyer ◽  
Guy A. Baldassarre
Keyword(s):  
New York ◽  
Habitat Use ◽  
Habitat Type ◽  
Home Ranges ◽  
Habitat Types ◽  
Black Duck ◽  
Disturbed Areas ◽  
Forested Areas ◽  
American Black ◽  
The Difference

There has been much speculation regarding whether breeding mallards (Anas platyrhynchos) and American black ducks (A. rubripes) use similar habitat types in forested areas, which could lead to increased interspecific contact. To study this issue, we used radiotelemetry during 1990–1991 on sympatric female mallards and black ducks breeding in the western Adirondack Mountains of New York. Mallard and black duck pairs occupied the general area at a density of 0.7 and 0.6/km2, respectively. Black duck home ranges tended to be larger than those of mallards, although the difference was not significant. Habitat composition within the home ranges of mallards and black ducks was similar, upland forest being the dominant habitat type, followed by wetlands, disturbed areas, and active residential sites. Within home ranges, mallards and black ducks were similar in their use of four major wetland habitat types. Our data suggest that undisturbed forest and habitat use within such areas may not serve as an isolating mechanism between breeding mallards and black ducks.

Habitat use and selection by takin in the Qinling Mountains, China

2016 ◽  
Vol 43 (8) ◽  
pp. 671 ◽  
Author(s):  
Wen-Bo Yan ◽  
Zhi-Gao Zeng ◽  
Hui-Sheng Gong ◽  
Xiang-Bo He ◽  
Xin-Yu Liu ◽  
...  
Keyword(s):  
Habitat Selection ◽  
Home Range ◽  
Habitat Use ◽  
Landscape Scale ◽  
Conservation Strategies ◽  
Large Species ◽  
Qinling Mountains ◽  
Habitat Types ◽  
Forest Habitats ◽  
Selection Of

Context Understanding habitat use and selection by threatened ungulates is a crucial prerequisite to prioritise management areas and for developing effective conservation strategies. Aims The aim of our research was to determine the habitat use and selection of takins (Budorcas taxicolor) in the middle range of the Qinling Mountains, China. Methods The study was conducted from August 2013 to August 2015. Global positioning system (GPS) radio-tracking was used to monitor 10 collared takins to gain their location information. The Manly–Chesson selectivity index and Bonferroni-adjusted 95% confidence intervals were applied to determine which habitats were selected. Key results Habitat use and selection by takins showed obvious individual differences. At the landscape scale, all of the four most common habitat types were preferred by takins. However, all takins avoided artificially planted larch forest, and farmland and village. Available habitats within the home ranges also mostly included the four common habitat types. At the home-range scale, all individuals had significant habitat selectivity during the entire tracking period and each season. The habitat use and selection within the home range varied obviously with season and showed sexual differences to a certain extent. Conclusions The habitat selection by takins is scale-dependent. At the landscape scale, takins are most likely to occur at sites covered by forest. At both landscape and home-range scales, our results indicated that takins need more diverse forest habitats, but none of the four most common forest habitats is essential for survival of this species. Implications The present work has provided more insight into the habitat use and habitat selection of takins in mountainous forest landscapes. Many measures such as maintaining a diversity of forest habitats, avoiding habitat alteration by invasion of exotic plants, and increasing the area of available habitats by relocating the villages from within to outside of the reserve are recommended to conserve this large species.

scholarly journals Nationwide inventory of mosquito biodiversity (Diptera: Culicidae) in Belgium, Europe

2012 ◽  
Vol 103 (2) ◽  
pp. 193-203 ◽  
Author(s):  
V. Versteirt ◽  
S. Boyer ◽  
D. Damiens ◽  
E.M. De Clercq ◽  
W. Dekoninck ◽  
...  
Keyword(s):  
Correspondence Analysis ◽  
Bird Migration ◽  
Mosquito Species ◽  
Habitat Type ◽  
Natural Areas ◽  
Habitat Types ◽  
Industrial Sites ◽  
Urban Rural ◽  
Urban Sites ◽  
Selection Of

AbstractTo advance our restricted knowledge on mosquito biodiversity and distribution in Belgium, a national inventory started in 2007 (MODIRISK) based on a random selection of 936 collection points in three main environmental types: urban, rural and natural areas. Additionally, 64 sites were selected because of the risk of importing a vector or pathogen in these sites. Each site was sampled once between May and October 2007 and once in 2008 using Mosquito Magnet Liberty Plus traps. Diversity in pre-defined habitat types was calculated using three indices. The association between species and environmental types was assessed using a correspondence analysis. Twenty-three mosquito species belonging to traditionally recognized genera were found, including 21 indigenous and two exotic species. Highest species diversity (Simpson 0.765) and species richness (20 species) was observed in natural areas, although urban sites scored also well (Simpson 0.476, 16 species). Four clusters could be distinguished based on the correspondence analysis. The first one is related to human modified landscapes (such as urban, rural and industrial sites). A second is composed of species not associated with a specific habitat type, including the now widely distributed Anopheles plumbeus. A third group includes species commonly found in restored natural or bird migration areas, and a fourth cluster is composed of forest species. Outcomes of this study demonstrate the effectiveness of the designed sampling scheme and support the choice of the trap type. Obtained results of this first country-wide inventory of the Culicidae in Belgium may serve as a basis for risk assessment of emerging mosquito-borne diseases.

Host Selection as an Adaptation To Host-Dependent Foraging Success in the Cattle Egret (Bubulcus Ibis)

Behaviour ◽  
1982 ◽  
Vol 79 (2-4) ◽  
pp. 212-229 ◽  
Author(s):  
Michael Gochfeld ◽  
Joanna Burger
Keyword(s):  
Host Selection ◽  
Past Century ◽  
General Area ◽  
Foraging Success ◽  
Cattle Egret ◽  
Feeding Success ◽  
Bubulcus Ibis ◽  
Preferred Hosts ◽  
Wide Population ◽  
Selection Of

AbstractIn southern Africa, the commensal foraging cattle egret has a wide variety of potential ungulate species from which to select its hosts. We found that the preferred hosts involved just a few of the available species. We predicted that ultimately the selection of hosts should be adapted to maximize egret foraging success. Selection is hierarchical with birds first choosing a general area in which one or more host species may be present. They then choose a host herd, and finally select an individual which they accompany as long as its actions are suitable and prey items are disturbed. The decision process remains flexible. Egrets freely switch hosts moving from one cow or wildebeest to another. We found the predicted correlation between egret and host walking rate (steps/min.), and also that feeding success was related to number of egret steps. We looked for evidence that egrets would select species and individuals that allowed them to move at the optimum rate for foraging. We found egrets achieving maximum success at walking rates between 10 and 30 steps per minute. When hosts moved more slowly or more quickly, feeding success was low, and egrets switched hosts more frequently. We censused wild animals in game parks and domestic animals on farms, and found a similar overall abundance (individuals/km). Wild animal herds provided fewer suitable hosts (individuals moving at the optimal rate for the egrets). We conclude that there are three components to host selection. Hosts must be available in adequate numbers and must be easy to locate. They must be suitable in terms of providing egrets with good foraging situations. They must be reliable in terms of remaining in the same general area day after day and in terms of consistent rates of locomotion. Although wildebeest, zebras, and buffalo fit one or two of the criteria, cattle fulfill all three. We speculate that the widespread increase in cattle farming in the past century may have facilitated the world wide population explosion of the cattle egret.

scholarly journals How to Select Potential Sites of Community Importance to the Natura 2000 Network: The Issue of Criteria

2014 ◽  
Vol 33 (2) ◽  
Author(s):  
Stanisław Tworek ◽  
Małgorzata Makomaska-Juchiewicz ◽  
Grzegorz Cierlik
Keyword(s):  
National Level ◽  
Habitat Type ◽  
Natura 2000 ◽  
Habitats Directive ◽  
Habitat Types ◽  
Natura 2000 Network ◽  
Practical Usefulness ◽  
Relative Value ◽  
Level Of Knowledge ◽  
Selection Of

AbstractTworek S., Makomaska-Juchiewicz M., Cierlik G.: How to select potential sites of community importance to the NATURA 2000 network: the issue of criteria. Ekológia (Bratislava), Vol. 33, No. 2, p. 127-137, 2014.In this paper, on the basis of experience gained at the elaboration of the Proposal of Natura 2000 network in Poland, we analyse the usefulness of criteria recommended in Annex III of the Habitats Directive (HD) for selecting proposed Sites of Community Importance (pSCI), i.e. potential Special Areas of Conservation. These are sites important for conservation of habitat types and species (except for birds), listed in Annexes I and II of the HD. The recommendations should allow arriving at the estimates of relative value of the selected areas vis-a-vis the national resources of each habitat type and species. These are, however, neither objective and quantified nor easy to apply criteria; because most of them rely on best expert judgement, which is subjective to a great extent. Moreover, the practical usefulness of the criteria is related to the level of knowledge of the distribution and size of resources of the habitat types and species of European importance. Our experience of selecting pSCI at national level indicates that this stage of work calls for more precise criteria than these recommended in the HD. We present our proposal of domestic criteria, which make easier the preliminary selection of pSCI that were tested in work with local experts responsible for regional proposals of sites to the Natura 2000 network in Poland. Because of the far-reaching consequences entailing the designation of Natura 2000, we would like to encourage a widespread discussion on criteria for selecting pSCI.

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