scholarly journals Coexistence of three sympatric cormorants ( Phalacrocorax spp.); partitioning of time as an ecological resource

2016 ◽  
Vol 3 (5) ◽  
pp. 160175 ◽  
Author(s):  
Mylswamy Mahendiran
Keyword(s):  
Resource Partitioning ◽  
Resource Competition ◽  
Physiological Stress ◽  
Sympatric Species ◽  
Freshwater Wetlands ◽  
Foraging Habitat ◽  
Phalacrocorax Carbo ◽  
Late Afternoon ◽  
Temporal Partitioning ◽  
Foraging Time

Resource partitioning is well known along food and habitat for reducing competition among sympatric species, yet a study on temporal partitioning as a viable basis for reducing resource competition is not empirically investigated. Here, I attempt to identify the mechanism of temporal partitioning by intra- and interspecific diving analyses of three sympatric cormorant species at different freshwater wetlands around the Delhi region. Diving results indicated that cormorants opted for a shallow diving; consequently, they did not face any physiological stress. Moreover, diving durations were linked with seasons, foraging time and foraging habitats. Intraspecific comparison suggested that cormorants spent a longer time underwater in early hours of the day. Therefore, time spent for dive was higher in the forenoon than late afternoon, and the interspecific analysis also yielded a similar result. When Phalacrocorax niger and Phalacrocorax fuscicollis shared the same foraging habitat, they tended to differ in their foraging time (forenoon/afternoon). However, when P. niger and Phalacrocorax carbo shared the same foraging time, they tended to use different foraging habitats (lentic/lotic) leading to a mechanism of resource partitioning. Thus, sympatric cormorants effectively use time as a resource to exploit the food resources and successful coexistence.

scholarly journals Diet Drives Differences in Reproductive Synchrony in Two Sympatric Mountain Ungulates in the Himalaya

2021 ◽  
Vol 9 ◽  
Author(s):  
Tanushree Srivastava ◽  
Ajith Kumar ◽  
Vinod Kumar ◽  
Govindhaswamy Umapathy
Keyword(s):  
Diet Quality ◽  
Seasonal Variations ◽  
Vegetation Index ◽  
Resource Competition ◽  
Physiological Stress ◽  
Sympatric Species ◽  
Plant Phenology ◽  
Musk Deer ◽  
Reproductive Synchrony ◽  
Diet Type

Ungulates in higher latitudes and altitudes experience sharp seasonal changes in forage abundance and quality. In response, ungulates show varying degrees of synchrony in reproduction. Diet type has been hypothesized to be a determinant of differences in reproductive synchrony. Analyses at global scales using proxies of plant phenology such as climate, latitude and Normalized Difference Vegetation Index (NDVI) have found no evidence in support because such proxies do not capture differences in phenology among plant taxa at local scales. We compared seasonal variations in diet quality with reproductive synchrony in the Himalayan musk deer (Moschus chrysogaster), a browser, and the Himalayan goral (Naemorhedus goral), a grazer, in mid-altitude Himalaya. We also compared seasonal variations in physiological stress using fecal glucocorticoid metabolite (FGM). We identified different stages of female reproductive cycle using fecal concentrations of metabolites of estradiol, pregnanediol-3-glucuronide (PdG) and testosterone and used fecal crude protein (CP) as an indicator of diet quality. In musk deer, fecal estradiol and PdG concentrations showed a dispersed estrous and parturition, respectively. Goral had a more synchronized estrous and parturition. Estrous cycles in both species occurred when diet quality was poor, but parturition occurred when diet quality was high. Greater seasonality in reproduction in goral is driven by sharp phenological changes in graminoids on which it feeds, compared to slow changes in browse on which musk deer feeds. Thus, we show that diet type drives the differences in reproductive synchrony in these two sympatric species. Spring and summer with highest diet quality were times of highest stress in both the ungulates. We hypothesize predation pressure from feral dogs and resource competition with livestock as plausible explanations for this, which need to be tested in future. Our findings also highlight the need for studying relationships among plant phenology, diet type and reproductive biology of ungulates at local scales if we are to understand species responses to global phenomena such as climate change.

Resource partitioning and overlap in three sympatric species of Ips bark beetles (Coleoptera: Scolytidae)

Oecologia ◽  
2001 ◽  
Vol 128 (3) ◽  
pp. 443-453 ◽  
Author(s):  
Bruce D. Ayres ◽  
Matthew P. Ayres ◽  
Mark D. Abrahamson ◽  
Stephen A. Teale
Keyword(s):  
Resource Partitioning ◽  
Bark Beetles ◽  
Sympatric Species

Another new, diminutive Rock Gecko (Cnemaspis Strauch) from Peninsular Malaysia and a discussion of resource partitioning in sympatric species pairs

Zootaxa ◽  
2010 ◽  
Vol 2569 (1) ◽  
pp. 55 ◽  
Author(s):  
L. LEE GRISMER ◽  
CHAN KIN ONN ◽  
EVAN QUAH ◽  
MOHD ABDUL MUIN ◽  
ANNA E. SAVAGE ◽  
...  
Keyword(s):  
New Species ◽  
Body Size ◽  
Endemic Species ◽  
Resource Partitioning ◽  
Sympatric Species ◽  
Southeast Asian ◽  
Peninsular Malaysia ◽  
Activity Period ◽  
Species Pairs

A new, diminutive species of Rock Gecko, Cnemaspis shahruli sp. nov. from Penang Island, Penang; Pulau Jerejak, Penang; Pulau Pangkor, Perak; and the adjacent mainland at Sungai Sedim, Kedah was previously confused with juveniles of the sympatric, endemic species C. affinis (Stoliczka) on Penang Island. Cnemaspis shahruli sp. nov. is diagnosed from all other Southeast Asian Cnemaspis on the basis of several unique aspects of squamation, coloration, and body size. It is proposed that this new species has a more extensive mainland distribution than is presented here based on its southernmost record on Pulau Pangkor, Perak. A pattern of resource partitioning on the basis of body size, habitat, and activity period among sympatric species pairs of Cnemaspis is discussed.

Foraging-habitat selection by bats at an urban–rural interface: comparison between a successful and a less successful species

2004 ◽  
Vol 82 (7) ◽  
pp. 1157-1164 ◽  
Author(s):  
Joseph E Duchamp ◽  
Dale W Sparks ◽  
John O Whitaker, Jr.
Keyword(s):  
Habitat Selection ◽  
Habitat Use ◽  
Compositional Analysis ◽  
Sympatric Species ◽  
Eptesicus Fuscus ◽  
Foraging Habitat ◽  
Tree Cavities ◽  
Urban Rural ◽  
Regional Population ◽  
Suburban Development

We compared habitat use of two sympatric species of bat in a rural area undergoing suburban development. The two species are similar in diet and foraging-habitat use but differ in current roosting habitat, and exhibit contrasting regional population trends. Evening bat, Nycticeius humeralis (Rafinesque, 1818), populations are declining in central Indiana, whereas big brown bat, Eptesicus fuscus (Beauvois, 1796), populations are increasing. We assessed habitat selection by 22 adult female bats using radiotelemetry and compositional analysis. Eptesicus fuscus used several roosts across the study area; all but one roosted in human-made structures. Nycticeius humeralis clustered roosts within a small group of woodlots; all roosted in tree cavities. Eptesicus fuscus foraged for longer periods of time and nonreproductive individuals of this species had larger foraging ranges than N. humeralis. Both species foraged primarily in agricultural and wooded areas. During foraging, N. humeralis showed greater foraging-site fidelity and a stronger selection for agricultural and wooded areas than E. fuscus. We suggest that N. humeralis in our study area is probably more sensitive to suburban development near their roosts than E. fuscus.

scholarly journals Resource Partitioning of Scots Pine (Pinus sylvestris L.) by Pine Shoot Beetles in Stands under Stress Conditions

Forests ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1336
Author(s):  
Andrzej Borkowski
Keyword(s):  
Scots Pine ◽  
Resource Partitioning ◽  
Multiple Linear Regression Model ◽  
Significant Degree ◽  
Sympatric Species ◽  
Site Quality ◽  
Explanatory Variables ◽  
Use Of Resources ◽  
Pine Shoot Beetles ◽  
Spatial Specialization

The pine shoot beetles Tomicus piniperda L. and T. minor Hartwig are sympatric species that occur on Scots pine in two habitats. Feeding by the beetles in tree crowns causes significant losses in tree growth and disturbs the crown’s proper development. A review of the subject literature showed that there had been no previous studies of interspecific competition in stands with different degrees of crown damage. The aim of this work was to assess the resource partitioning of stems by the two species in stands with damaged and undamaged crowns. Data were collected in the years 1992–2008 in stands containing Scots pine located at different distances from timber yards. A total of 259 natural traps were laid, and measurements of height and diameter at breast height were made for 900 pines. The surface area of each stem was divided into 20 equal sections by making a division lengthwise (into units) and laterally (into an upper and lower part). In total, 90,501 egg galleries of pine shoot beetles were counted on 9560 stem sections. Feeding by pine shoot beetles in the crowns of pines reduces site productivity and the nutritional suitability of stems. The results of niche segregation indicate pine shoot beetles exhibited spatial specialization in the use of resources. prefers the thicker part of the stem, and T. minor the thinner part. The population of T. piniperda on the trap logs was described using a multiple linear regression model with three explanatory variables. As a result of regression modelling, from the set of variables representing characteristics of habitats, trees and trap logs and the parameters of infestation, the following explanatory variables were selected: range of colonisation of a trap log (rc), site quality class (sqc), and crown undamaged (cu). The explanatory variables included in the MLRM model explain to a significant degree (p < 0.05) the niche breadth of T. piniperda on trap logs. In all validated plots, the mean real and model values for the niche of T. piniperda on the trap logs are similar (p > 0.5), confirming the high accuracy of the developed model.

Niche overlap and sett-site resource partitioning for two sympatric species of badger

2009 ◽  
Vol 21 (2) ◽  
pp. 89-100 ◽  
Author(s):  
L. Zhang ◽  
Y.-B. Zhou ◽  
C. Newman ◽  
Y. Kaneko ◽  
D.W. Macdonald ◽  
...  
Keyword(s):  
Resource Partitioning ◽  
Niche Overlap ◽  
Sympatric Species

scholarly journals Effects of Intraguild Predation: Evaluating Resource Competition between Two Canid Species with Apparent Niche Separation

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Adam J. Kozlowski ◽  
Eric M. Gese ◽  
Wendy M. Arjo
Keyword(s):  
Habitat Use ◽  
Resource Competition ◽  
Sympatric Species ◽  
Distribution Data ◽  
Niche Separation ◽  
Behavioral Strategies ◽  
Dietary Preferences ◽  
Kit Fox ◽  
Prey Resources ◽  
Species Specific

Many studies determine which habitat components are important to animals and the extent their use may overlap with competitive species. However, such studies are often undertaken after populations are in decline or under interspecific stress. Since habitat selection is not independent of interspecific stress, quantifying an animal's current landscape use could be misleading if the species distribution is suboptimal. We present an alternative approach by modeling the predicted distributions of two sympatric species on the landscape using dietary preferences and prey distribution. We compared the observed habitat use of kit foxes (Vulpes macrotis) and coyotes (Canis latrans) against their predicted distribution. Data included locations of kit foxes and coyotes, carnivore scat transects, and seasonal prey surveys. Although habitats demonstrated heterogeneity with respect to prey resources, only coyotes showed habitat use designed to maximize access to prey. In contrast, kit foxes used habitats which did not align closely with prey resources. Instead, habitat use by kit foxes represented spatial and behavioral strategies designed to minimize spatial overlap with coyotes while maximizing access to resources. Data on the distribution of prey, their dietary importance, and the species-specific disparities between predicted and observed habitat distributions supports a mechanism by which kit fox distribution is derived from intense competitive interactions with coyotes.

Habitat and food resource partitioning among four species of darters (Percidae: Etheostoma) in a southern Ontario stream

1982 ◽  
Vol 60 (7) ◽  
pp. 1635-1641 ◽  
Author(s):  
Michael D. Paine ◽  
Julian J. Dodson ◽  
Geoffrey Power
Keyword(s):  
Relative Abundance ◽  
Resource Partitioning ◽  
Food Resource ◽  
Habitat Utilization ◽  
Foraging Habitat ◽  
Southern Ontario ◽  
Food Partitioning ◽  
Benthic Prey ◽  
Food Resource Partitioning

Resource partitioning among four species of darters (Percidae: Etheostoma) in an Ontario stream was investigated by determining diet and relative abundance in two habitats. The four species partitioned both food and habitat resources. E. caeruleum and E. flabellare dominated the riffles; the former took prey from rock surfaces, the latter took prey from between and beneath rocks. Etheostoma microperca and E. nigrum dominated the weed beds; the former feeding on prey on and around plants, the latter feeding on benthic prey. Diets were closely related to morphology, but habitat utilization was not. Determining the importance of habitat versus food partitioning is difficult, because microhabitat and foraging habitat may be nearly identical.

Resource partitioning among five sympatric species of freshwater turtles from the wet–dry tropics of northern Australia

2017 ◽  
Vol 44 (3) ◽  
pp. 219 ◽  
Author(s):  
Michael A. Welsh ◽  
J. Sean Doody ◽  
Arthur Georges
Keyword(s):  
Resource Partitioning ◽  
Niche Overlap ◽  
Sympatric Species ◽  
Dry Season ◽  
Gut Contents ◽  
Microhabitat Use ◽  
Freshwater Turtles ◽  
Northern Australia ◽  
Dietary Shift ◽  
Dry Tropics

Context Resource partitioning of diet and microhabitat was examined for five sympatric species of freshwater turtles in the Daly River in the northern end of Northern Territory (Top End) in Australia. The Daly River supports a high diversity of freshwater turtles, making it the ideal place to study a freshwater turtle community. Aims To determine the dry-season diet and microhabitat use of Carettochelys insculpta, Elseya dentata, Chelodina oblonga, Emydura victoriae and Emydura subglobosa worrelli and examine intraspecific and interspecific niche overlap and ontogenetic dietary shift. Methods Gut contents were collected by stomach flushing, and microhabitat use was determined by recording where each turtle was first seen before capture. Diet and microhabitat use were compared using an index of relative importance. Niche overlap was measured with Horn’s overlap index. Key results Carettochelys insculpta is an opportunistic omnivore that feeds mostly on ribbonweed (Vallisneria spiralis) and aquatic snails. Elseya dentata is herbivorous, feeding primarily on aquatic algae. The diets of C. insculpta and E. dentata overlapped moderately, but the overall niche overlap was low because they occupied different microhabitats within the river. Chelodina oblonga fed very little, and may use the Daly River as a dry-season refuge. Emydura victoriae is molluscivorous, consuming more molluscs as it grows. This ontogenetic dietary shift was associated with megacephaly (extreme broadly expanded head that is too large to fit into the carapace) and expanded triturating surfaces. This specialisation allows adult E. victoriae to feed exclusively on molluscs and so their diet overlapped little with other species. Emydura subglobosa worrelli was omnivorous, consuming mostly freshwater sponge and apparently preferring more lentic water. Conclusions The freshwater turtles of the wet–dry tropics are usually reported as being heavily reliant on the seeds, fruits and leaves of riparian vegetation; however, the present study showed that the dry-season diet in perennial rivers is primarily of aquatic origin. Implications The study suggested that populations of C. insculpta, E. dentata and E. victoriae could be threatened by broad-scale development in northern Australia if there were substantive impacts on aquatic macrophytes and molluscs in the Daly River system.

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