Habitat use by corn mice (Calomys musculinus) in cropfield borders of agricultural ecosystems in Argentina

2012 ◽  
Vol 39 (2) ◽  
pp. 112 ◽  
Author(s):  
Ivana Simone ◽  
Cecilia Provensal ◽  
Jaime Polop
Keyword(s):  
Habitat Use ◽  
Land Surface ◽  
Linear Models ◽  
Management Strategies ◽  
Habitat Characteristics ◽  
Tree Cover ◽  
Small Rodent ◽  
Individual Plant ◽  
Calomys Musculinus ◽  
Rodent Abundance

Context Calomys musculinus (Cricetidae, Sigmodontinae) is a small rodent species widely distributed in Argentina and particularly abundant in agroecosystems of the Pampean region, where it is known to select border habitats over cropfields. Aims The aim of the present research was to assess habitat use by C. musculinus in cropfield borders. Assuming that the number of rodent captures in each border reflects the intensity of use, we intended to identify the habitat characteristics that would account for abundance differences among borders. Methods Seasonal trapping sessions were carried out in borders of the rural zone of Chucul, Córdoba. Environmental variables were registered from both field surveys and remote-sensing imagery. Generalised linear models were used to identify the habitat variables associated with C. musculinus habitat use. Key results General fit of the models was fairly good; spring, summer and autumn models explained more than 55% of the variation in C. musculinus abundance among borders. Individual plant species were significant predictors of C. musculinus abundance, but they varied with seasons, whereas tree cover and border width were significant predictors in most seasons studied. In general, rodent abundance was positively associated with peanut and maize crops or maize stubbles and negatively related to soybean or its stubbles. In the coldest seasons, rodent abundance increased with increasing land-surface temperature of the border. Conclusions Border use by C. musculinus appeared to respond to differences in border quality, which seems to be more affected by those environmental characteristics that entail a reduction of the predatory risk rather than by those that involve food supply. Crop-fields may partially afford C. musculinus food requirements. Implications Because C. musculinus is the natural reservoir of a zoonotic agent, the identification of the habitat characteristics affecting rodent population numbers in borders may be of crucial importance for the implementation of ecologically based rodent-management strategies aimed at reducing human–rodent contacts. We suggest that wide borders, particularly those contiguous to maize and peanut cropfields, should be understood as priority sites for the implementation of specific control actions.

scholarly journals Monitoring and conservation of the rare orchid Didimoplexis verrucosa in the face of change

Bothalia ◽  
2021 ◽  
Vol 51 (2) ◽  
Author(s):  
T.H.C. Mostert ◽  
R.E. Mostert
Keyword(s):  
Conservation Status ◽  
Management Strategies ◽  
Population Monitoring ◽  
Environmental Indicators ◽  
Habitat Characteristics ◽  
Similar Degree ◽  
Suitable Habitat ◽  
Individual Plant ◽  
Accurate Identification ◽  
Term Survival

Abstract Background: Didymoplexis verrucosa is a cryptic leafless saprophytic ground orchid (~70 mm tall) growing on the coastal forest floors of southern Zululand and classified as Vulnerable (D2). As part of a population monitoring programme, 960 man-hours of species specific searching over five consecutive flowering seasons were conducted, yielding only one individual plant. Objective: The aim of this study was to increase detection rate by developing a profile of environmental indicators for the accurate identification of suitable habitat. Methods: A detailed description of suitable habitat was compiled based on the Braun-Blanquet approach. Results: The results showed that key attributes shared by localities include similar topographic position in the landscape, hydrology, soils, vegetation composition and structure, forest age, leaf-litter composition of the forest floor, the co-occurrence of Isoglossa woodii, and a similar degree of protection from sunlight, wind and desiccation. Significance of the findings: This profile of essential habitat characteristics can be used as a surrogate in the absence of actual locality data when identifying target conservation areas and compiling management strategies for this very cryptic species. A by-product of this habitat analysis was the discovery of a long list of impacts on the long term survival of D. verrucosa. The combination of these stochastic and deterministic events will drive habitat change at rates beyond the species’ ability to adapt. Managing these variables forms the crux of its successful conservation. A conservation status revision, based on the formal IUCN criteria, indicate that D. verrucosa should be reclassified as Critically Endangered Category B2a and D.  

scholarly journals Responses of small mammals to habitat characteristics in Southern Carpathian forests

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ana Maria Benedek ◽  
Ioan Sîrbu ◽  
Anamaria Lazăr
Keyword(s):  
Habitat Use ◽  
Small Mammals ◽  
Management Practices ◽  
Geographical Location ◽  
Elevational Gradient ◽  
Abundant Species ◽  
Habitat Characteristics ◽  
Tree Cover ◽  
Myodes Glareolus ◽  
Wide Range

AbstractCompared to Northern Carpathians, the small mammal fauna of Southern Carpathian forests is poorly known, with no data on habitat use; our study seeks to fill this gap. To this end, we conducted a survey in the Southern Carpathians for five years, assessing habitat use by small mammals in forests along an elevational gradient. Trapping was done using live traps set in transects at elevations between 820 and 2040 m. For each transect we evaluated variables related to vegetation structure, habitat complexity, and geographical location. We considered abundance, species composition and species richness as response variables. The rodents Apodemus flavicollis and Myodes glareolus and the shrew Sorex araneus were common and dominant. Their abundance were positively correlated with tree cover, the best explanatory variable. Responses to other variables were mixed. The strong divergence in the relative habitat use by the three most abundant species may act as a mechanism that enables their coexistence as dominant species, exploiting the same wide range of habitat resources. Overall, habitat use in our study area was similar to that reported from Northern Carpathians, but we found also important differences probably caused by the differences in latitude and forest management practices.

scholarly journals Habitat modelling locates nesting areas of the Endangered Black-capped Petrel Pterodroma hasitata on Hispaniola and identifies habitat loss

2020 ◽  
pp. 1-18
Author(s):  
YVAN G. SATGÉ ◽  
ERNST RUPP ◽  
ADAM BROWN ◽  
PATRICK G. R. JODICE
Keyword(s):  
Habitat Loss ◽  
Forest Fires ◽  
Environmental Variables ◽  
Linear Models ◽  
Habitat Characteristics ◽  
Tree Cover ◽  
Suitable Habitat ◽  
Nesting Habitat ◽  
Understorey Vegetation ◽  
Breeding Sites

Summary The Black-capped Petrel or Diablotin Pterodroma hasitata has a fragmented and declining population estimated at c.1,000 breeding pairs. On land, the species nests underground in steep ravines with dense understorey vegetation. The only confirmed breeding sites are located in the mountain ranges of Hispaniola in the Caribbean, where habitat loss and degradation are continuing threats. Other nesting populations may still remain undiscovered but, to locate them, laborious in situ nest searches must be conducted over expansive geographical areas. To focus nest-search efforts more efficiently, we analysed the environmental characteristics of Black-capped Petrel nesting habitat and modeled suitable habitat on Hispaniola using openly available environmental datasets. We used a univariate generalized linear model to compare the habitat characteristics of active Black-capped Petrel nests sites with those of potentially available sites (i.e. random pseudo-absences). Elevation, distance to coast, and the influence of tree cover and density emerged as important environmental variables. We then applied multivariate generalized linear models to these environmental variables that showed a significant relationship with petrel nesting activity. We used the top performing model of habitat suitability model to create maps of predicted suitability for Hispaniola. In addition to areas of known petrel activity, the model identified possible nesting areas for Black-capped Petrels in habitats not previously considered suitable. Based on model results, we estimated the total area of predicted suitable nesting habitat for Black-capped Petrels on Hispaniola and found that forest loss due to hurricanes, forest fires, and encroachment from agriculture had severely decreased availability of predicted suitable habitat between 2000 and 2018.

scholarly journals The influence of habitat use on harvest vulnerability of cow elk (Cervus canadensis)

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0242841
Author(s):  
Maksim Sergeyev ◽  
Brock R. McMillan ◽  
Kent R. Hersey ◽  
Randy T. Larsen
Keyword(s):  
Habitat Selection ◽  
Home Range ◽  
Habitat Use ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Habitat Characteristics ◽  
Tree Cover ◽  
Selection Function ◽  
Hunting Season ◽  
Cervus Canadensis

Pressure from hunting can alter the behavior and habitat selection of game species. During hunting periods, cervids such as elk (Cervus canadensis) typically select for areas further from roads and closer to tree cover, while altering the timing of their daily activities to avoid hunters. Our objective was to determine the habitat characteristics most influential in predicting harvest risk of elk. We captured 373 female elk between January 2015 and March 2017 in the Uinta-Wasatch-Cache National Forest and surrounding area of central Utah, USA. We determined habitat selection during the hunting season using a resource selection function (RSF) for 255 adult cow elk. Additionally, we used a generalized linear mixed model to evaluate risk of harvest based on habitat use within home ranges (3rd order selection) as well as the location of the home range on the landscape to evaluate vulnerability on a broader scale. Female elk selected for areas that reduced hunter access (rugged terrain, within tree cover, on private land). Age, elevation and distance to roads within a home range were most influential in predicting harvest risk (top model accounted for 36.2% of AIC weight). Elevation and distance to trees were most influential in predicting risk when evaluating the location of the home range (top model accounted for 42.1% of AIC weight). Vulnerability to harvest was associated with proximity to roads. Additionally, survival in our landscape decreased with age of femaleelk.

scholarly journals Wild Steps in a Semi-wild Setting? Habitat Selection and Behavior of European Bison reintroduced to an Anthropogenic Landscape

2018 ◽  
Author(s):  
Pil Birkefeldt Møller Pedersen ◽  
Joanna B. Olsen ◽  
Brody Sandel ◽  
Jens-Christian Svenning
Keyword(s):  
Habitat Selection ◽  
Habitat Use ◽  
Ecological Impact ◽  
Spatial Models ◽  
Environmental Parameters ◽  
Habitat Characteristics ◽  
Tree Cover ◽  
European Bison ◽  
Agricultural Field ◽  
Release Area

AbstractRecently, several wild or semi-wild herds of European bison have been reintroduced across Europe. It is essential for future successful bison reintroductions to know how the European bison use different habitats, which environmental parameters drive their habitat selection, and whether their habitat use and behavioural patterns in new reintroduction sites differ from habitats where European bison have been roaming freely for a long time.Here, we address these questions for a 40-ha enclosed site that has been inhabited by semi-free ranging European bison since 2012. The site, Vorup Meadows, is adjacent to the Gudenå river in Denmark and consists of human-modified riparian meadows. During 2013 we monitored the behavioural pattern and spatial use of the 11 bison present and in parallel carried out floristic analyses to assess habitat structure and food quality in the enclosure. We tested habitat use and selection against environmental parameters such as habitat characteristics, plant community traits, topography, and management area (release area vs. meadow area) using linear regression and spatial models.The bison herd had comparable diurnal activity patterns as observed in previous studies on free-roaming bison herds. Topography emerged as the main predictor of the frequency of occurrence in our spatial models, with high-lying drier areas being used more. Bison did not prefer open areas over areas with tree cover when accounting for habitat availability. However, they spent significantly more time in the release area, a former agricultural field with supplementary fodder, than expected from availability compared to the rest of the enclosure, a meadow with tree patches. We wish to increase awareness of possible long-term ethological effects of the release site and the management protocols accomplished here that might reduce the ecological impact by the bison in the target habitat, and thereby compromise or even oppose the conservation goals of the conservation efforts.

Habitat Use of Woodpeckers in the Big Woods of Eastern Arkansas

2012 ◽  
Vol 3 (1) ◽  
pp. 89-97 ◽  
Author(s):  
David G. Krementz ◽  
Sarah E. Lehnen ◽  
Jason D. Luscier
Keyword(s):  
Habitat Use ◽  
Linear Models ◽  
Negative Relationship ◽  
Habitat Characteristics ◽  
Diameter At Breast Height ◽  
Use Patterns ◽  
Breast Height ◽  
Northern Flicker ◽  
Melanerpes Erythrocephalus ◽  
Colaptes Auratus

Abstract The Big Woods of eastern Arkansas contain some of the highest densities of woodpeckers recorded within bottomland hardwood forests of the southeastern United States. A better understanding of habitat use patterns by these woodpeckers is a priority for conservationists seeking to maintain these high densities in the Big Woods and the Lower Mississippi Alluvial Valley as a whole. Hence, we used linear mixed-effects and linear models to estimate the importance of habitat characteristics to woodpecker density in the Big Woods during the breeding seasons of 2006 and 2007 and the winter of 2007. Northern flicker Colaptes auratus density was negatively related to tree density both for moderate (>25 cm diameter at breast height) and larger trees (>61 cm diameter at breast height). Red-headed woodpeckers Melanerpes erythrocephalus also had a negative relationship with density of large (>61 cm diameter at breast height) trees. Bark disfiguration (an index of tree health) was negatively related to red-bellied woodpecker Melanerpes carolinus and yellow-bellied sapsucker Sphyrapicus varius densities. No measured habitat variables explained pileated woodpecker Dryocopus pileatus density. Overall, the high densities of woodpeckers observed in our study suggest that the current forest management of the Big Woods of Arkansas is meeting the nesting, roosting, and foraging requirements for these birds.

Modeling cetacean habitat use in an urban coastal area in southeastern Brazil

2020 ◽  
Vol 642 ◽  
pp. 227-240
Author(s):  
L Lodi ◽  
R Tardin ◽  
G Maricato
Keyword(s):  
Habitat Use ◽  
Protected Areas ◽  
Linear Models ◽  
Anthropogenic Activities ◽  
Buffer Zone ◽  
Humpback Whales ◽  
Southeastern Brazil ◽  
Major Influence ◽  
Cetacean Species ◽  
Few Data

Most studies of cetacean habitat use do not consider the influence of anthropogenic activities. We investigated the influence of environmental and anthropogenic variables on habitat use by humpback Megaptera novaeangliae and Bryde’s whales Balaenoptera brydei off the coast of the Brazilian city of Rio de Janeiro. Although there are 2 marine protected areas (MPAs) in this area, few data are available on cetacean habitat use or on the overlap of different cetacean species within these MPAs. Our aim was to evaluate the effectiveness of the MPAs and propose a buffer zone to better protect the biodiversity of the study area. We conducted systematic surveys and developed spatial eigenvector generalized linear models to characterize habitat use by the species in the study area. Habitat use by humpback whales was influenced only by depth, whereas for Bryde’s whales there was the additional influence of anthropogenic variables. For Bryde’s whales, which use the area for feeding, sea surface temperature and the distance to anchorages had a major influence on habitat use. We also showed that neither of the MPAs in the study area adequately protects the hotspots of either whale species. Most of the humpback whale grid cells with high sighting predictions were located within 2 km of the MPAs, while areas of high sighting prediction of Bryde’s whales were located up to 5 km from the MPAs, closer to beaches. Our findings provide important insights for the delimitation of protected areas and zoning of the MPAs.

scholarly journals Small rodent cycles influence interactions among predators in a boreal forest ecosystem

2021 ◽  
Vol 66 (4) ◽  
pp. 583-593
Author(s):  
Rocío Cano-Martínez ◽  
David Carricondo-Sanchez ◽  
Olivier Devineau ◽  
Morten Odden
Keyword(s):  
Structural Equation ◽  
Agricultural Land ◽  
Structural Equation Models ◽  
Red Fox ◽  
Interspecific Interactions ◽  
Small Rodent ◽  
Generalist Predator ◽  
Pine Marten ◽  
Mustela Nivalis ◽  
Rodent Abundance

AbstractCyclic fluctuations of prey have profound effects on the functioning of ecosystems, for example, by changing the dynamics, behavior, and intraguild interactions of predators. The aim of this study was to assess the effect of rodent cyclic fluctuations in the interspecific interactions of a guild of small- and medium-sized predators: red fox (Vulpes vulpes), pine marten (Martes martes), and weasels (Mustela erminea and Mustela nivalis) in the boreal ecosystem. We analyzed eight years (2007–2014) of snow tracking data from southeastern Norway using structural equation models to assess hypothesized networks of causal relationships. Our results show that fluctuations in rodent abundance alter the strength of predator’s interactions, as well as the effect of determinant environmental variables. Pine marten and weasel abundances were positively associated with rodent population growth rate, but not red fox abundance. All predators were positively associated with each other; however, the association between red fox and the other predators weakened when rodents increased. Rodent fluctuations had variable effects on the habitat use of the predators. The presence of agricultural land was important for all predators, but this importance weakened for the mustelids as rodent abundance increased. We discuss the shifting role of interference and exploitative competition as possible mechanisms behind these patterns. Overall, we highlight the importance of accounting for the dynamics of prey resources when studying interspecific interactions among predators. Additionally, we demonstrate the importance of monitoring the predator populations in order to anticipate undesirable outcomes such as increased generalist predator abundances to the detriment of specialists.

scholarly journals Quantifying Tree Cover Loss in Urban Forests within Nairobi City Metropolitan Area from Earth Observation Data

2020 ◽  
Vol 3 (1) ◽  
pp. 78
Author(s):  
Francis Oloo ◽  
Godwin Murithi ◽  
Charlynne Jepkosgei
Keyword(s):  
Land Cover ◽  
Metropolitan Area ◽  
Land Surface ◽  
Urban Forest ◽  
Urban Forests ◽  
Earth Observation ◽  
Tree Cover ◽  
Observation Data ◽  
Vegetation Health ◽  
Earth Observation Data

Urban forests contribute significantly to the ecological integrity of urban areas and the quality of life of urban dwellers through air quality control, energy conservation, improving urban hydrology, and regulation of land surface temperatures (LST). However, urban forests are under threat due to human activities, natural calamities, and bioinvasion continually decimating forest cover. Few studies have used fine-scaled Earth observation data to understand the dynamics of tree cover loss in urban forests and the sustainability of such forests in the face of increasing urban population. The aim of this work was to quantify the spatial and temporal changes in urban forest characteristics and to assess the potential drivers of such changes. We used data on tree cover, normalized difference vegetation index (NDVI), and land cover change to quantify tree cover loss and changes in vegetation health in urban forests within the Nairobi metropolitan area in Kenya. We also used land cover data to visualize the potential link between tree cover loss and changes in land use characteristics. From approximately 6600 hectares (ha) of forest land, 720 ha have been lost between 2000 and 2019, representing about 11% loss in 20 years. In six of the urban forests, the trend of loss was positive, indicating a continuing disturbance of urban forests around Nairobi. Conversely, there was a negative trend in the annual mean NDVI values for each of the forests, indicating a potential deterioration of the vegetation health in the forests. A preliminary, visual inspection of high-resolution imagery in sample areas of tree cover loss showed that the main drivers of loss are the conversion of forest lands to residential areas and farmlands, implementation of big infrastructure projects that pass through the forests, and extraction of timber and other resources to support urban developments. The outcome of this study reveals the value of Earth observation data in monitoring urban forest resources.

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