Microhabitat selection in the potentially endangered wolf spider Donacosa merlini (Araneae, Lycosidae): implications for spider conservation

2008 ◽  
Vol 86 (11) ◽  
pp. 1280-1288 ◽  
Author(s):  
C. Fernández-Montraveta ◽  
M. Cuadrado
Keyword(s):  
Habitat Selection ◽  
Habitat Quality ◽  
Spatial Scales ◽  
Conservation Status ◽  
Regional Scale ◽  
Wolf Spider ◽  
Distribution Area ◽  
Suitable Habitat ◽  
Ecological Requirements ◽  
Trade Offs

Habitat quality affects many components of animal fitness and animals are expected to be distributed in the space accordingly. Mismatch between habitat preferences and fitness may relate to scale-dependent effects and trade-offs between costs and benefits of moving to high-quality habitats. We investigated the effects of habitat quality and habitat selection in Donacosa merlini Alderweireldt and Jocqué, 1991, a burrowing wolf spider included in the Spanish Invertebrates Red Data Book. Particularly, we compared burrow size and density and analysed the relationship between burrow presence and vegetation at two different scales. At a regional scale, we found strong differences in burrow size and density. Burrow density affected burrow aggregation, which was utmost under mean densities. At both spatial scales, burrows were found at relatively clear (or low-covered) patches, as scrubs were lower and nearest vegetation was farther from burrows than randomly expected. Our results suggest habitat selection and effects of habitat quality on the life history of D. merlini. In spite of the recent expansion of the species distribution area, our data support the need for suitable habitat management programs. Information about ecological requirements is paramount to correctly assess spider conservation status. This topic has received little attention in spite of the diversity and the relevance of spider ecological roles.

scholarly journals Surveys of wintering Little Bustards Tetrax tetrax in central Spain: distribution and population estimates at a regional scale

2007 ◽  
Vol 17 (1) ◽  
pp. 23-34 ◽  
Author(s):  
ELADIO L. GARCÍA DE LA MORENA ◽  
MANUEL B. MORALES ◽  
EDUARDO DE JUANA ◽  
FRANCISCO SUÁREZ
Keyword(s):  
Survey Methodology ◽  
Spatial Scales ◽  
Regional Scale ◽  
Suitable Habitat ◽  
Flock Size ◽  
Central Spain ◽  
Tetrax Tetrax ◽  
Potential Habitats ◽  
Available Information ◽  
Tagus Valley

Developing a standardized survey methodology to census and estimate the size of wintering populations is a main conservation priority for the endangered Little Bustard. We present a standard and repeatable methodology to census wintering Little Bustard populations at a regional scale, and the first statistically reliable population estimate of a Little Bustard wintering population in Spain. We carried out two surveys, in 2003 and 2004, using UTM 10 km × 10 km squares as census units, which were subjected to stratified sampling over the species' potential distribution range in the region of Madrid (Central Spain). Only the areas of potentially suitable habitat within squares of known winter presence of the species were considered. The species' winter distribution in Madrid was fairly constant between years, showing a fragmented pattern in three main nuclei. The number of Little Bustards observed was consistent between surveys (752 and 786 birds, respectively), with birds grouped in an average of 32 flocks (1 to 350 birds, mean = 27.9 birds). No between-winter differences in flock size were observed, although differences between sectors were significant. The highest densities were observed in the Tagus valley (mean density = 2.9 birds km−2, 293 birds), followed by north-eastern farmland (mean density = 0.6 bird km−2, 269 birds). The estimated size of the Little Bustard population wintering in the Madrid region was 1,051 (95% CI = 1,043–1,231). This calculation was based on recorded population density, measured as the number of birds per square kilometre, and considers the potential habitats available in each sector. We propose this methodology as adequate for surveying any Little Bustard wintering area, at both regional and smaller spatial scales. Survey results are consistent with previous tentative estimates for the region of Madrid, and with available information on Little Bustard movements. Sixty-five per cent of squares with Little Bustard presence were outside any protected area, which makes the wintering Little Bustard population of Madrid highly vulnerable to habitat disappearance and may affect the viability of breeding nuclei whose individuals winter in the region.

scholarly journals Habitat selection of Marbled Teal and White-headed Duck during the breeding and wintering seasons in south-eastern Spain

2012 ◽  
Vol 23 (3) ◽  
pp. 344-359 ◽  
Author(s):  
ESTHER SEBASTIÁN-GONZÁLEZ ◽  
CRISTINA FUENTES ◽  
MARCOS FERRÁNDEZ ◽  
JOSÉ L. ECHEVARRÍAS ◽  
ANDY J. GREEN
Keyword(s):  
Habitat Selection ◽  
Spatial Scales ◽  
Management Strategies ◽  
Open Water ◽  
Spatial Diversity ◽  
Suitable Habitat ◽  
Brood Rearing ◽  
South Eastern ◽  
Natural Park ◽  
Selection Of

SummaryUnderstanding habitat requirements is vital for developing successful management strategies for threatened species. In this study we analyse the habitat selection of two globally threatened waterbirds (Marbled Teal Marmaronetta angustirostris and White-headed Duck Oxyura leucocephala) coexisting in an internationally important wetland (El Hondo Natural Park, south-eastern Spain) at three spatial scales. We surveyed adults and broods of these species fortnightly during two consecutive years and we related density and presence of birds to several habitat variables. At a pond-selection scale, the density of both species was related to the surface area of the ponds, with Marbled Teal showing avoidance of medium-sized ponds, and White-headed Ducks strong selection for the largest ponds. Within ponds, Marbled Teal avoided open waters, and was mainly associated with Phragmites reedbeds, but also selected areas with saltmarsh and Scirpus vegetation, especially for brood-rearing. White-headed Duck made more use of deeper areas with open water, especially in winter, and Phragmites was the only emergent vegetation with which it associated. When breeding success was very high in 2000, strong creching of broods was observed in White-headed Duck, but not in Marbled Teal. In order to provide suitable habitat for both species, there is a need to maintain spatial diversity with a combination of large wetlands suitable for both species and small, vegetated ones suitable for the Marbled Teal.

Habitat selection by roe deer and sheep: does habitat ranking reflect resource availability?

1999 ◽  
Vol 77 (5) ◽  
pp. 776-783 ◽  
Author(s):  
Atle Mysterud ◽  
Per Kristian Larsen ◽  
Rolf Anker Ims ◽  
Eivind Østbye
Keyword(s):  
Habitat Selection ◽  
Food Availability ◽  
Resource Availability ◽  
Roe Deer ◽  
Antipredator Behavior ◽  
Spatial Scales ◽  
Ovis Aries ◽  
Domestic Sheep ◽  
Trade Offs ◽  
Temporal And Spatial

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.

scholarly journals Densities, plant sizes, and spatial distributions of six wild populations of Lophophora williamsii (Cactaceae) in Texas, U.S.A.

2021 ◽  
Vol 15 (1) ◽  
pp. 149-160
Author(s):  
Anna Ermakova ◽  
Carolyn V. Whiting ◽  
Keeper Trout ◽  
Colin Clubbe ◽  
Martin K. Terry ◽  
...  
Keyword(s):  
Regional Differences ◽  
Spatial Scales ◽  
Conservation Status ◽  
Regional Scale ◽  
Plant Size ◽  
South Texas ◽  
Wild Populations ◽  
Initial Information ◽  
West Texas ◽  
Plant Densities

Lophophora williamsii (Cactaceae) is thought to be threatened by habitat loss and overharvesting. However, basic demographic and habitat information to evaluate its conservation status have been lacking. We surveyed six wild populations of this species, three in South Texas and three in West Texas, to begin to address this gap. We found high levels of heterogeneity in plant presence and density at multiple spatial scales. While plant densities were not consistently different between South and West Texas, plants were significantly larger in West Texas. The two regions differ strongly in precipitation, temperature, elevation, and topography, all of which are correlated at the regional scale. Therefore, it was not possible to identify which of these variables, or other factors such as competition and human harvesting, may be responsible for the regional differences in plant size. However, our results provide initial information for determining the conservation status of this species.

scholarly journals Setting Favourable Habitat Reference Values for breeding birds: general principles and examples for passerine birds

2013 ◽  
Vol 24 (3) ◽  
pp. 263-271 ◽  
Author(s):  
MATTIA BRAMBILLA ◽  
CLAUDIO CELADA ◽  
MARCO GUSTIN
Keyword(s):  
Habitat Selection ◽  
Habitat Quality ◽  
Reference Values ◽  
Breeding Success ◽  
Suitable Habitat ◽  
Distribution Models ◽  
Species Population ◽  
Definition Of ◽  
Range Of Values

SummarySetting Favourable Reference Values (FRVs) can assist the definition of the conservation status of a species. FRVs may consider population, habitat, and range. FRVs can indicate a range of values for different parameters, which should allow the long-term persistence of a species/population. We propose a method for the definition of reference values for the habitat (FRV-H or HRV) of breeding bird species. HRV should cover habitat extent and quality, both required to ensure long-term persistence. Extent HRV should express a measure of suitable area, whereas quality HRV could be defined as the range of values for habitat variables known to affect habitat quality. To define an extent HRV, we built species distribution models (SDMs) and set extent HRV as the extent of potentially suitable habitat under a conservative approach. Quality HRV should refer to environmental determinants/correlates of occurrence and breeding success, and should be defined by the identification of the habitat factors affecting occurrence and reproduction. When habitat selection is adaptive, habitat suitability may approximate habitat quality, being correlated with breeding success. In that case, fine-scaled habitat/distribution models may be used to identify determinants/correlates of reproductive output, and such species-habitat relationships may help define quality HRV. We show examples using the Red-backed Shrike Lanius collurio as a model. The use of habitat selection models, which can be made spatially explicit generating distribution models, may assist the definition of both extension and quality HRVs. Species-habitat models can allow the individuation of factors and relative values affecting species occurrence/reproduction (quality HRV), and the definition of the spatial distribution and quantity of potentially suitable habitat (extent HRV). Our approach is one of the possible ones, aiming at finding a “suitable” trade-off between affordable data and scientific precision. HRVs should be used together with population and range FRVs to assess the status of a species/population.

scholarly journals Using Mountain Lion Habitat Selection in Management

2020 ◽  
Author(s):  
JA Dellinger ◽  
B Cristescu ◽  
J Ewanyk ◽  
DJ Gammons ◽  
D Garcelon ◽  
...  
Keyword(s):  
Habitat Selection ◽  
Endangered Species ◽  
Home Range ◽  
Multiple Scales ◽  
Puma Concolor ◽  
Spatial Scales ◽  
Suitable Habitat ◽  
Mountain Lions ◽  
Mountain Lion ◽  
Management And Conservation

© 2019 The Wildlife Society Wildlife agencies are generally tasked with managing and conserving species at state and local levels simultaneously. Thus, it is necessary for wildlife agencies to understand basic ecological processes of a given species at multiple scales to aid decision making at commensurately varied spatial and behavioral scales. Mountain lions (Puma concolor) occur throughout California, USA, and are at the center of a variety of management and conservation issues. For example, they are genetically and demographically at risk in 1 region yet apparently stable and negatively affecting endangered species in another. Currently, no formal plan exists for mountain lions in California to deal with these diverse scenarios involving issues of local mountain lion population viability and problems related to predation of endangered species. To facilitate development of a state-wide management and conservation plan, we quantified habitat selection by mountain lions at 2 spatial scales across the range of environmental conditions in which the species is found in California. Our analyses used location data from individuals (n = 263) collared across the state from 2001–2019. At the home range scale, mountain lions selected habitat to prioritize meeting energetic demands. At the within home range scale, mountain lions avoided areas of human activity. Further, our analyses revealed 165,350–170,085 km2, depending on season, of suitable mountain lion habitat in California. Fifty percent of the suitable habitat was on unprotected lands and thus vulnerable to development. These habitat selection models will help in the development of a state-wide conservation and management plan for mountain lions in California by guiding mountain lion population monitoring through time, prioritization of habitat to be conserved for maintaining demographic connectivity and gene flow, and efforts to mediate mountain lion-prey interactions. Our work and application area will help with wildlife policy and management decisions related to depredation problems at the local scale and issues of habitat connectivity at the statewide scale. © 2019 The Wildlife Society.

scholarly journals Using Mountain Lion Habitat Selection in Management

2020 ◽  
Author(s):  
JA Dellinger ◽  
B Cristescu ◽  
J Ewanyk ◽  
DJ Gammons ◽  
D Garcelon ◽  
...  
Keyword(s):  
Habitat Selection ◽  
Endangered Species ◽  
Home Range ◽  
Multiple Scales ◽  
Puma Concolor ◽  
Spatial Scales ◽  
Suitable Habitat ◽  
Mountain Lions ◽  
Mountain Lion ◽  
Management And Conservation

© 2019 The Wildlife Society Wildlife agencies are generally tasked with managing and conserving species at state and local levels simultaneously. Thus, it is necessary for wildlife agencies to understand basic ecological processes of a given species at multiple scales to aid decision making at commensurately varied spatial and behavioral scales. Mountain lions (Puma concolor) occur throughout California, USA, and are at the center of a variety of management and conservation issues. For example, they are genetically and demographically at risk in 1 region yet apparently stable and negatively affecting endangered species in another. Currently, no formal plan exists for mountain lions in California to deal with these diverse scenarios involving issues of local mountain lion population viability and problems related to predation of endangered species. To facilitate development of a state-wide management and conservation plan, we quantified habitat selection by mountain lions at 2 spatial scales across the range of environmental conditions in which the species is found in California. Our analyses used location data from individuals (n = 263) collared across the state from 2001–2019. At the home range scale, mountain lions selected habitat to prioritize meeting energetic demands. At the within home range scale, mountain lions avoided areas of human activity. Further, our analyses revealed 165,350–170,085 km2, depending on season, of suitable mountain lion habitat in California. Fifty percent of the suitable habitat was on unprotected lands and thus vulnerable to development. These habitat selection models will help in the development of a state-wide conservation and management plan for mountain lions in California by guiding mountain lion population monitoring through time, prioritization of habitat to be conserved for maintaining demographic connectivity and gene flow, and efforts to mediate mountain lion-prey interactions. Our work and application area will help with wildlife policy and management decisions related to depredation problems at the local scale and issues of habitat connectivity at the statewide scale. © 2019 The Wildlife Society.

scholarly journals DENSITIES, PLANT SIZES, AND SPATIAL DISTRIBUTIONS OF SIX WILD POPULATIONS OF LOPHOPHORA WILLIAMSII (CACTACEAE) IN TEXAS, U.S.A

2020 ◽  
Author(s):  
Anna Ermakova ◽  
Carolyn V. Whiting ◽  
Keeper Trout ◽  
Colin Clubbe ◽  
Martin K. Terry ◽  
...  
Keyword(s):  
Spatial Scales ◽  
Conservation Status ◽  
Regional Scale ◽  
Plant Size ◽  
South Texas ◽  
Wild Populations ◽  
Initial Information ◽  
West Texas ◽  
Plant Densities ◽  
Para Determinar

ABSTRACTLophophora williamsii (Cactaceae) is thought to be threatened by habitat loss and overharvesting. However, basic demographic and habitat information to evaluate its conservation status has been lacking. We surveyed six wild populations of this species, three in South Texas and three in West Texas, to begin to address this gap. We found high levels of heterogeneity in plant presence and density at multiple spatial scales. While plant densities were not consistently different between South and West Texas, plants were significantly larger in West Texas. The two regions differ strongly in precipitation, temperature, elevation, and topography, all of which are correlated at the regional scale. Therefore, it was not possible to identify which of these variables, or other factors such as competition and human harvesting, may be responsible for the regional differences in plant size. However, our results provide initial information for determining the conservation status of this species.RESUMENLophophora williamsii (Cactaceae) se considera amenazada por la pérdida de hábitat y cosecha excesiva. Sin embargo, se carece de información demográfica y ambiental básica para evaluar su estado de conservación. Para abordar este déficit, examinamos seis poblaciones salvajes de esta especie (tres en el sur y tres en el oeste de Texas respectivamente). Encontramos altos niveles de heterogeneidad en la presencia y densidad de plantas en múltiples escalas espaciales. Las densidades no son consistentemente diferentes entre el sur y el oeste, pero las plantas son significativamente más grandes en el oeste. Las dos regiones difieren notablemente en precipitación, temperatura, elevación y topografía. Todas estas variables están correlacionadas a escala regional, por lo que no es posible identificar cuál de ellas (u otros factores como la competencia y la cosecha humana) causan las diferencias regionales observadas en el tamaño de la planta. Nuestros resultados proporcionan información fundamental para determinar el estado de conservación de esta especie.

Spatial variability in diet, condition and growth of juvenile plaice (Pleuronectes platessa) at sandy beach nursery grounds on the south-west coast of Ireland

2010 ◽  
Vol 91 (6) ◽  
pp. 1215-1223 ◽  
Author(s):  
F. De Raedemaecker ◽  
J. Keating ◽  
D. Brophy ◽  
I. O'Connor ◽  
D. Mc Grath
Keyword(s):  
Habitat Quality ◽  
Large Scale ◽  
Spatial Scales ◽  
Condition Index ◽  
Spatial And Temporal Variation ◽  
Small Scale ◽  
Suitable Habitat ◽  
Pleuronectes Platessa ◽  
Wide Range ◽  
South West Coast

Characterization of suitable habitat for settlement of juvenile flatfish is important for the management of nursery areas. Food availability is one important determinant of habitat quality that can affect the condition and growth, and thus survival, of flatfish. Spatial and temporal variation in diet has been widely studied for several species of flatfish. However, levels of intraspecific variation in diet at small spatial scales are relatively unknown, with most studies focusing only on large scale variability. This study investigates how diet, growth and condition of juvenile plaice, Pleuronectes platessa, varies over two spatial scales (10s of kilometres and 100s of metres). Juvenile plaice were collected from three beaches and from three replicate hauls on each beach using a beach seine in September 2007 and 2008. Gut content analyses of 108 juvenile plaice within the size-range of 70–90 mm were carried out. Diet composition in plaice guts differed among beaches and hauls suggesting that food abundance and availability differed at both spatial scales. A significant positive correlation was observed between a morphological condition index and the prey diversity in the gut. This suggests that fish which specialize on a limited number of prey items (perhaps due to a greater abundance of certain prey) may do better than fish which feed on a wide range of prey types. Significant differences in condition were observed between hauls and between beaches, while recent and total otolith growth varied between beaches but not between hauls. The results highlight the importance of considering small scale variation when attempting to link habitat quality to feeding, growth and condition of juvenile flatfish.

scholarly journals Setting the Flow Accumulation Threshold Based on Environmental and Morphologic Features to Extract River Networks from Digital Elevation Models

2021 ◽  
Vol 10 (3) ◽  
pp. 186
Author(s):  
HuiHui Zhang ◽  
Hugo A. Loáiciga ◽  
LuWei Feng ◽  
Jing He ◽  
QingYun Du
Keyword(s):  
Spatial Scales ◽  
Digital Elevation Models ◽  
Regional Scale ◽  
Drainage Density ◽  
River Network ◽  
Landscape Patterns ◽  
Estimation Methods ◽  
River Networks ◽  
Flow Accumulation ◽  
Digital Elevation

Determining the flow accumulation threshold (FAT) is a key task in the extraction of river networks from digital elevation models (DEMs). Several methods have been developed to extract river networks from Digital Elevation Models. However, few studies have considered the geomorphologic complexity in the FAT estimation and river network extraction. Recent studies estimated influencing factors’ impacts on the river length or drainage density without considering anthropogenic impacts and landscape patterns. This study contributes two FAT estimation methods. The first method explores the statistical association between FAT and 47 tentative explanatory factors. Specifically, multi-source data, including meteorologic, vegetation, anthropogenic, landscape, lithology, and topologic characteristics are incorporated into a drainage density-FAT model in basins with complex topographic and environmental characteristics. Non-negative matrix factorization (NMF) was employed to evaluate the factors’ predictive performance. The second method exploits fractal geometry theory to estimate the FAT at the regional scale, that is, in basins whose large areal extent precludes the use of basin-wide representative regression predictors. This paper’s methodology is applied to data acquired for Hubei and Qinghai Provinces, China, from 2001 through 2018 and systematically tested with visual and statistical criteria. Our results reveal key local features useful for river network extraction within the context of complex geomorphologic characteristics at relatively small spatial scales and establish the importance of properly choosing explanatory geomorphologic characteristics in river network extraction. The multifractal method exhibits more accurate extracting results than the box-counting method at the regional scale.

Sign in / Sign up

Export Citation Format

Share Document