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 ◽  
...  

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.

Author(s):  
Sergio Alejandro Terán-Juárez ◽  
Eduardo Pineda ◽  
Jorge Víctor Horta-Vega ◽  
José Rogelio Cedeño-Vázquez ◽  
Alfonso Correa-Sandoval ◽  
...  

2020 ◽  
Vol 71 (1) ◽  
pp. 21-35
Author(s):  
Lorenzo Rugiero ◽  
Massimo Capula ◽  
Daniele Dendi ◽  
Fabio Petrozzi ◽  
Massimiliano Di Vittorio ◽  
...  

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.


2014 ◽  
Vol 12 (4) ◽  
pp. 803-810 ◽  
Author(s):  
Vinicius J. Giglio ◽  
Johnatas Adelir-Alves ◽  
Leopoldo C. Gerhardinger ◽  
Fabiano C. Grecco ◽  
Felippe A. Daros ◽  
...  

Developing survey strategies for threatened species is often limited by access to sufficient individuals to acquire information needed to design appropriate conservation measures. The goliath grouper (Epinephelus itajara) is a large reef fish, globally classified as critically endangered. In Brazil, fishing has been prohibited since 2002. Herein we investigated habitat use and abundance of E. itajara in Brazil drawn from a participative survey, which engaged volunteer divers in data-collection. A total of 188 reports were recorded between 2005 to 2011 throughout 13 Brazilian states. Our results revealed that habitat type influenced the relationship between total length and depth of occurrence of E. itajara. We observed a significant difference between habitats, artificial presented a nonlinear and natural an asymptotic relationship. This study underscores the importance of developing conservation measures addressing specific habitats and locations to enhance population recovery. Artificial structures (shipwrecks and manmade reefs) are critical habitats that must be considered as highly sensitive areas to E. itajara strategic conservation policies. We suggest the creation and implementation of marine protected areas, as key strategies for E. itajaraconservation, especially for artificial habitats and aggregation sites.


The Condor ◽  
2001 ◽  
Vol 103 (1) ◽  
pp. 38-44 ◽  
Author(s):  
Katia Lombardini ◽  
Robert E. Bennetts ◽  
Christophe Tourenq

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.


2003 ◽  
Vol 37 (2) ◽  
pp. 292-300 ◽  
Author(s):  
James W. Watson ◽  
Kelly R. McAllister ◽  
D. John Pierce

2008 ◽  
Vol 86 (3) ◽  
pp. 170-176 ◽  
Author(s):  
I. Barja ◽  
S. Rosellini

We examined whether group size in red deer ( Cervus elaphus L., 1758) and roe deer ( Capreolus capreolus (L., 1758)) under predation risk by Iberian wolves ( Canis lupus L., 1758) is affected by the type of habitat in which the deer reside. We hypothesized that group size (i) would be larger in open than in closed habitats, since it is an antipredator response, and (ii) would vary more with habitat type in the species that had higher wolf predation rates. In the study area, wolves were the only predator of wild ungulates, with roe deer being the main target prey. We performed monthly transects along paths to observe the group size of red and roe deer. In roe deer, the mean group size was significantly higher in open than in closed habitats, serving as an antipredator response. However, in red deer, habitat type did not affect group size. The results indicate that under predation risk by wolves the habitat type influences the grouping behavior of roe deer but not red deer. Furthermore, compared with forests, heaths offer less protection from predators and species in this habitat would benefit from larger group sizes.


2005 ◽  
Vol 83 (7) ◽  
pp. 983-988 ◽  
Author(s):  
Javier A Rodríguez-Robles ◽  
Manuel Leal ◽  
Jonathan B Losos

Habitat selection can directly affect the fitness of an individual and the evolutionary dynamics of the population to which that organism belongs. We studied habitat use of the Puerto Rican yellow-chinned anole (Anolis gundlachi Peters, 1876) to examine whether this arboreal lizard uses its environment in a nonrandom manner. Males and females preferred woody vegetation substrates over nonwoody plants and sierra palms (Prestoea acuminata var. montana (Graham) A. Henderson and G. Galeano) as perching sites, and they also selected wider vegetation than what was randomly available. Selection for minimizing conspicuousness to potential predators and for increased locomotion capacity may help explain the preference for woody substrates and broader surfaces, respectively. Anolis gundlachi relies almost exclusively on visual cues for foraging and social interactions, and using wider perches also increases an individual's ability to scan a larger proportion of its territory. Our findings thus indicate that the nonrandom habitat use of free-ranging A. gundlachi leads to the selection of perching substrates that may increase performance of ecologically relevant capabilities.


1988 ◽  
Vol 66 (4) ◽  
pp. 919-924 ◽  
Author(s):  
Hélène Jolicoeur ◽  
Michel Crête

Survival, movements, home ranges, habitat selection, and diets of 13 orphaned and 13 non-orphaned moose calves were compared during their first winter. Survival of four other calves that became separated from their mothers was also monitored. The study took place during three winters between December 1978 and April 1983. Overall, winter survival rates between the two groups did not differ. When mortality did occur, it involved solitary (orphaned and separated) calves during a severe winter. Movements and home-range sizes of the two groups were also similar. Biomass of forage on winter sites, forage utilization, and importance of tree cover were similar on sites chosen by orphaned and non-orphaned calves. Minor differences were observed in the order of preference of browse species. Five solitary calves were involved in either temporary or permanent associations with other moose.


1999 ◽  
Vol 77 (5) ◽  
pp. 776-783 ◽  
Author(s):  
Atle Mysterud ◽  
Per Kristian Larsen ◽  
Rolf Anker Ims ◽  
Eivind Østbye

Habitat ranking is often assumed to reflect food availability, but habitat selection may involve trade-offs, for example, between selecting for food or cover. We tested whether the habitat selection of 27 radio-collared European roe deer (Capreolus capreolus) and 10 free-ranging domestic sheep (Ovis aries) on a forest range in southern Norway reflected resource availability. We predicted that ruminants of different feeding types would use habitats according to the main forage class, but that antipredator behavior might remove the correlation between habitat selection and food availability, thus making temporal and spatial scaling crucial. As predicted, habitat selection by sheep was highly correlated with grass availability on both the home-range and study-area scales. The habitat ranking of roe deer habitat selection did not correlate with the availability of herbs on either scale, but rather was correlated with the availability of canopy cover. We found a clear effect of temporal scale on habitat selection by roe deer. During summer, roe deer used forest habitats with more forage to a greater extent when they were active than when they were inactive, and tended to use habitats with greater availability of herbs at night. We conclude that scale-dependent trade-offs in habitat selection may cause inconsistent habitat rankings when pooled across temporal and spatial scales.


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