scholarly journals Arthropod Resource Partitioning Among Omnivorous Tanagers (Tangara SPP.) in Western Ecuador

The Auk ◽  
2007 ◽  
Vol 124 (1) ◽  
pp. 197-209 ◽  
Author(s):  
Kazuya Naoki
Keyword(s):  
Resource Use ◽  
Foraging Ecology ◽  
Bird Species ◽  
Sympatric Species ◽  
Factors Affecting ◽  
Use Patterns ◽  
Interspecific Differences ◽  
Fruit Species ◽  
Mixed Species Flocks ◽  
Different Characteristics

Abstract The distribution and abundance of food are primary factors affecting resource-use patterns in birds. Many bird species eat several food types, which may differ in their distribution and overall abundance. I studied foraging ecology of seven sympatric species of Tangara at Mindo, Ecuador, to determine whether the patterns of resource use differed between two food types: arthropods and fruits. Interspecific differences in arthropod-foraging were manifested in the fine segregation of microhabitat preference combined with different habitat use. By contrast, interspecific differences in fruit-foraging were manifested in preferences for different plant genera, often associated with different habitats. No evidence was found for spatial partitioning of the same fruit species. Interspecific overlap in fruit-for- aging was 3× higher than that in arthropod-foraging, and species of Tangara that frequently joined the same mixed-species flocks differed largely in arthropod-foraging but overlapped greatly in fruit-foraging. The differences in patterns between arthropod and fruit-foraging may be explained by the different characteristics of arthropods and fruits as food resources. High sympatry of species of Tangara and other omnivorous tanagers, in general, appears to be maintained not because fruits are abundant, resulting in little competition for them, but because these tanagers specialize on different microhabitats for foraging arthropods. Segregación de Artrópodos como Recurso Alimenticio de Tangaras Omnívoras (Tangara spp.) en el Oeste de Ecuador

Locomotor correlates of ecomorph designation in Anolis: an examination of three sympatric species from Jamaica

1992 ◽  
Vol 70 (4) ◽  
pp. 725-739 ◽  
Author(s):  
G. Lawrence Powell ◽  
Anthony P. Russell
Keyword(s):  
Body Size ◽  
Niche Partitioning ◽  
Sympatric Species ◽  
Limb Length ◽  
Greater Antilles ◽  
Adult Size ◽  
Allometric Models ◽  
Use Patterns ◽  
Interspecific Differences

Scaling of locomotor structures (limb length, scansor area, and intergirdle distance) in three Jamaican Anolis species (A. garmani, A. grahami, and A. opalinus) is examined. Reference to structural-niche use patterns and partitionings typical of these three species is made. Each species represents a separate Anolis ecomorph, differing from the others in adult size, shape, and structural niche. All are part of a single intra-island phyletic radiation. Allometric models indicate that intra- and inter-specific differences in proportion of locomotor structures are not necessarily ontogenetically invariant, but that all three species ontogenetically arrive at, or have attained, the differences in proportion typical of their adult sizes. Differences in adult proportion between two species are not functions of body size alone but are the products of different scaling trajectories. No intraspecific differences in structural-niche use are documented, but interspecific differences are well defined: the greater the number of differences in locomotor scaling between two species, the greater the structural-niche partitioning. We suggest that the locomotor structure scaling patterns observed in these three species are typical of the ecomorphs that they represent. Analogous ontogenetic patterns of development should be displayed by independently derived representatives of these ecomorphs from other Greater Antilles islands.

scholarly journals From hunters to nature observers: a record of 53 years of diver attitudes towards sharks and rays and marine protected areas

2011 ◽  
Vol 62 (6) ◽  
pp. 755 ◽  
Author(s):  
Sally Whatmough ◽  
Ingrid Van Putten ◽  
Andrew Chin
Keyword(s):  
Protected Areas ◽  
Marine Protected Areas ◽  
Resource Use ◽  
Scientific Data ◽  
Attitudinal Change ◽  
Use Patterns ◽  
Positive Effects ◽  
Economic Information ◽  
Perceptions And Attitudes ◽  
Conservation Awareness

Human values, perceptions, attitudes and interactions with the natural environment have been found to change over time, with social and economic information used to inform management decisions and actions. Content analysis is applied here to a 53-year long collection of the popular dive magazine, SportDiving, to identify recreational divers’ experiences with regard to sharks and rays, the Great Barrier Reef (GBR) and marine protected areas (MPAs). This analysis suggests there has been a diversification of diver activities with the emergence of passive-observational activities such as SCUBA diving. Attitudes towards sharks and rays have changed significantly, with recreational divers changing from a group that could be described as adventure-seeking hunters to a group that can be described as nature-appreciating observers, suggesting an increase in conservation awareness. The GBR continues to be a highly regarded dive destination, with divers perceiving positive effects of protection within MPAs. However, declines in the abundance of large fish and sharks and rays were occasionally reported throughout the 53 year period. Collectively, these types of data can show changes in resource-use patterns, perceptions and attitudes and provide information that supplements scientific monitoring data. These data may be valuable where scientific data is scarce, historical records difficult to obtain, and where attitudinal change can significantly affect future resource use.

scholarly journals Modeling Community-Scale Natural Resource Use in a Transboundary Southern African Landscape: Integrating Remote Sensing and Participatory Mapping

2021 ◽  
Vol 13 (4) ◽  
pp. 631
Author(s):  
Kyle D. Woodward ◽  
Narcisa G. Pricope ◽  
Forrest R. Stevens ◽  
Andrea E. Gaughan ◽  
Nicholas E. Kolarik ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Land Use ◽  
Resource Use ◽  
Training Data ◽  
Systems Science ◽  
Participatory Mapping ◽  
Land Use Patterns ◽  
Modeling Framework ◽  
Use Patterns ◽  
Human Habitation

Remote sensing analyses focused on non-timber forest product (NTFP) collection and grazing are current research priorities of land systems science. However, mapping these particular land use patterns in rural heterogeneous landscapes is challenging because their potential signatures on the landscape cannot be positively identified without fine-scale land use data for validation. Using field-mapped resource areas and household survey data from participatory mapping research, we combined various Landsat-derived indices with ancillary data associated with human habitation to model the intensity of grazing and NTFP collection activities at 100-m spatial resolution. The study area is situated centrally within a transboundary southern African landscape that encompasses community-based organization (CBO) areas across three countries. We conducted four iterations of pixel-based random forest models, modifying the variable set to determine which of the covariates are most informative, using the best fit predictions to summarize and compare resource use intensity by resource type and across communities. Pixels within georeferenced, field-mapped resource areas were used as training data. All models had overall accuracies above 60% but those using proxies for human habitation were more robust, with overall accuracies above 90%. The contribution of Landsat data as utilized in our modeling framework was negligible, and further research must be conducted to extract greater value from Landsat or other optical remote sensing platforms to map these land use patterns at moderate resolution. We conclude that similar population proxy covariates should be included in future studies attempting to characterize communal resource use when traditional spectral signatures do not adequately capture resource use intensity alone. This study provides insights into modeling resource use activity when leveraging both remotely sensed data and proxies for human habitation in heterogeneous, spectrally mixed rural land areas.

scholarly journals Demographic consequences of foraging ecology explain genetic diversification in Neotropical bird species

2021 ◽  
Author(s):  
Matthew J. Miller ◽  
Eldredge Bermingham ◽  
Benjamin L. Turner ◽  
Justin C. Touchon ◽  
Andrew B. Johnson ◽  
...  
Keyword(s):  
Foraging Ecology ◽  
Bird Species

Current state of cold hardiness research on fruit crops

1997 ◽  
Vol 77 (3) ◽  
pp. 399-420 ◽  
Author(s):  
Pauliina Palonen ◽  
Deborah Buszard
Keyword(s):  
Cold Hardiness ◽  
Cultural Practices ◽  
Limiting Factor ◽  
Screening Methods ◽  
Fruit Crops ◽  
Factors Affecting ◽  
Fruit Species ◽  
Current State ◽  
Deep Supercooling ◽  
Cold Hardy

This article gives an overview of the current state of cold hardiness research in fruit crops by reviewing the recently published studies on cold hardiness of both tree fruit and berry crops. Topics discussed include cold hardiness of fruit species, cultivars and different plant organs, biophysical and biochemical aspects of hardiness, evaluation of hardiness, as well as endogenous, cultural and environmental factors affecting cold hardiness in these species. Lack of cold hardiness is a major limiting factor for production of fruit crops in many regions of the world and improved cold hardiness one of the major objectives in numerous breeding programs and research projects. Screening cultivars or selections for cold hardiness is commonly done, and different methods applied to the evaluation of hardiness are discussed. The physical limit of deep supercooling may be a restricting factor for expanding the production of some fruit crops, such as Prunus species and pear. As for biochemical aspects, a relationship between carbohydrates and cold hardiness is most commonly found. Studies have also been made on different hardiness modifying cultural factors including rootstock, crop load, raised beds and application of growth regulators. The latter seems promising for some species. Cold hardiness is an extremely complex phenomenon and understanding different mechanisms involved is critical. Since hardiness is, however, primarily affected by genotype, developing cold-hardy fruit cultivars and effective screening methods for hardiness are essential. Finally, cultural practices may be improved to further enhance hardiness. Key words: Berries, cold hardiness, fruits, small fruits, stress, winter hardiness

scholarly journals Resource use and GHG emissions of eight tropical fruit species cultivated in Colombia

Fruits ◽  
2013 ◽  
Vol 68 (4) ◽  
pp. 303-314 ◽  
Author(s):  
Sophie Graefe ◽  
Jeimar Tapasco ◽  
Alonso Gonzalez
Keyword(s):  
Resource Use ◽  
Ghg Emissions ◽  
Tropical Fruit ◽  
Fruit Species

Endogenous biomarkers reveal diet partitioning among three sympatric species of swallows

The Auk ◽  
2021 ◽  
Author(s):  
Kaelyn H Bumelis ◽  
Michael D Cadman ◽  
Keith A Hobson
Keyword(s):  
Isotope Analysis ◽  
Sympatric Species ◽  
Tree Swallow ◽  
Population Declines ◽  
Interspecific Differences ◽  
Cliff Swallow ◽  
Aerial Insectivores ◽  
Breeding Grounds ◽  
Potential Factors ◽  
Δ 15N

Abstract Since the early 1990s, aerial insectivorous birds have shown serious population declines in North America, but it is not clear if factors common to all species within this guild account for these declines. Among sympatric swallows, population trends differ, and this may be due to differences in ecology operating throughout the annual cycle. Although these species all feed on aerial insects, prey taxa can differ tremendously in their “aeroecology” and use by swallows. We examined the potential for dietary differences among three species of swallows, Barn Swallow (Hirundo rustica), Cliff Swallow (Petrochelidon pyrrhonota), and Tree Swallow (Tachycineta bicolor), breeding sympatrically in southern Ontario, Canada. Potential interspecific differences in nestling diet were examined using two endogenous biomarkers, DNA barcoding of nestling feces and stable isotope analysis (δ 2H, δ 13C, δ 15N) of nestling feathers. We found evidence for differences in dietary sources of provisioned young where Barn Swallows provisioned more terrestrial-based prey, Cliff Swallows provisioned an intermediate diet, and Tree Swallows the most aquatic-emergent insect diet. We suggest this information may help to identify potential factors contributing to differential declines of aerial insectivores operating on the breeding grounds, including diet quality.

scholarly journals Color Differences Among Closely Related Species of Red-Breasted Meadowlarks (Sturnella)

The Condor ◽  
2007 ◽  
Vol 109 (3) ◽  
pp. 605-616
Author(s):  
Pilar Benites ◽  
Pablo L. Tubaro ◽  
Darío A. Lijtmaer ◽  
Stephen C. Lougheed ◽  
Muir D. Eaton
Keyword(s):  
Related Species ◽  
Short Wavelength ◽  
Visual Space ◽  
Color Discrimination ◽  
Threshold Value ◽  
Sympatric Species ◽  
Closely Related Species ◽  
Interspecific Differences ◽  
Sexually Selected Traits ◽  
Color Differences

Abstract Abstract. Interspecific differences in sexually selected traits may be important for maintaining reproductive isolation among closely related species living in sympatry. We present the first study of plumage color differences among males of partially sympatric species of South American red-breasted meadowlarks—the White-browed Blackbird (Sturnella superciliaris), the Pampas Meadowlark (S. defilippii), and the Long-tailed Meadowlark (S. loyca)—using reflectance spectrophotometry and the avian visual model of Vorobyev and Osorio (1998). Reflectance values of sexually dichromatic red plumage patches were measured on study skins. Total reflectance, reflectance in the short wavelength part of the spectrum, and several measures of spectral shape were extracted directly from the spectra. Our analyses revealed that S. loyca and S. defilippii were brighter and had higher reflectance in the short wavelength part of the spectrum than S. superciliaris. Minimum reflectance was located at higher wavelengths in breeding than in nonbreeding plumage. Interspecific distances in avian visual space obtained from the Vorobyev and Osorio (1998) model were considerably higher than the threshold value for color discrimination, indicating that the differences found are also detectable by birds. Taken together, these results show that the red plumage patches of these three species present significant color differences throughout the year, not only in the visible but also in the UV part of the spectrum.

Resource use by unexploited sympatric bobcats and coyotes in Oregon

1986 ◽  
Vol 64 (10) ◽  
pp. 2333-2338 ◽  
Author(s):  
G. W. Witmer ◽  
D. S. deCalesta
Keyword(s):  
Resource Use ◽  
Activity Patterns ◽  
Home Ranges ◽  
Felis Rufus ◽  
Clear Cut ◽  
Use Patterns ◽  
Mountain Beaver ◽  
Forested Areas ◽  
Aplodontia Rufa ◽  
Daily Activity Patterns

Unexploited populations of bobcats (Felis rufus) and coyotes (Canis latrans) were studied in the Elliott State Forest, Douglas and Coos counties, Oregon, from September 1981 to July 1982. A total of 633 radio locations of six bobcats and five coyotes were used to determine home ranges, activity, and habitat-use patterns. Twenty-five prey items were identified in bobcat and coyote scats. Diets of the two species were similar (overlap values were greater than 0.92 for all seasons). Mountain beaver (Aplodontia rufa) remains occurred in over 70% of the scats from both species. Home ranges for radio-collared animals averaged 14 km2 for male coyotes, 12 km2 for female coyotes, 11 km2 for one male bobcat, and 2 km2 for female bobcats. Bobcat and coyote home ranges overlapped in time as well as space. Radio-collared bobcats were detected on occasion within the same clear-cut sites concurrently with radio-collared coyotes, and daily activity patterns were nearly identical between the two predators. Bobcats and coyotes used open areas during nightly hunting activities and retired to forested areas during the day. Coyotes used grassy, more open clearings whereas bobcats favored brushy sites.

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