scholarly journals Niche partitioning and coexistence of two spiders of the genusPeucetia(Araneae, Oxyopidae) inhabitingTrichogoniopsis adenanthaplants (Asterales, Asteraceae): a population approach

2019 ◽  
Author(s):  
German Antonio Villanueva-Bonilla ◽  
Suyen Safuan-Naide ◽  
Mathias Mistretta Pires ◽  
João Vasconcellos-Neto

AbstractNiche theory suggests that the coexistence of ecologically similar species at the same site requires some form of resource partitioning that reduces or avoids interspecific competition. Here, we investigated the temporal and spatial niche differentiation of two sympatric congeneric spiders,Peucetia rubrolineataandP. flava, inhabitingTrichogoniopsis adenantha(Asteraceae) plants along an altitudinal gradient in various shaded and open areas in an Atlantic forest in Serra do Japi, SP, Brazil. In theory, the coexistence of twoPeucetiaspecies could be explained by: (1) temporal segregation; (2) differential use of the branches of the plant; (3) differential use of specific parts of the branches of the plant; (4) differential distribution in shaded and open areas; and (5) differential altitudinal distribution of the twoPeucetiaspecies. With respect to temporal niche, we observed that the two spider species had a similar age structure and similar fluctuation in abundance throughout the year. With respect to micro-habitat use, in both species, different instars used different plant parts, while the same instars of both species used the same type of substrate. However, the twoPeucetiaspecies segregated by meso-habitat type, withP. rubrolineatapreferringT. adenanthaplants in shaded areas andP. flavapreferring those in open areas. Our results support the hypothesis of niche partitioning begetting diversity, and highlight the importance of analysing habitat use at multiple scales to understand mechanisms related to coexistence.

2018 ◽  
Vol 32 (5) ◽  
pp. 1069 ◽  
Author(s):  
Stefano Mammola ◽  
Miquel A. Arnedo ◽  
Paolo Pantini ◽  
Elena Piano ◽  
Nicolò Chiappetta ◽  
...  

Speciation in subterranean habitats is commonly explained as the result of divergent selection in geographically isolated populations; conversely, the contribution of niche partitioning in driving subterranean species diversification has been rarely quantified. The present study integrated molecular and morphological data with a hypervolume analysis based on functional traits to investigate a potential case of parapatric speciation by means of niche differentiation in two sibling spiders inhabiting contiguous subterranean habitats within a small alpine hypogean site. Troglohyphantes giachinoi, sp. nov. and T. bornensis are diagnosed by small details of the genitalia, which are likely to be involved in a reproductive barrier. Molecular analysis recovered the two species as sister, and revealed a deep genetic divergence that may trace back to the Messinian (~6 million years ago). The hypervolume analysis highlighted a marginal overlap in their ecological niches, coupled with morphological character displacement. Specifically, T. giachinoi, sp. nov. exhibits morphological traits suitable for thriving in the smaller pores of the superficial network of underground fissures (Milieu Souterrain Superficiel, MSS), whereas T. bornensis shows a greater adaptation to the deep subterranean habitat. Our results suggest that different selective regimes within the subterranean environment, i.e. deep caves v. MSS, may either drive local speciation or facilitate contiguous distributions of independently subterranean adapted species.


2021 ◽  
Author(s):  
S. M. Glaser ◽  
R. M. Feitosa ◽  
A. Koch ◽  
N. Goß ◽  
F. S. do Nascimento ◽  
...  

AbstractTropical ants experience intense intra- and interspecific competition for food sources, which influences their activity pattern and foraging strategies. Even though different ant species can coexist through spatial and temporal niche partitioning, direct competition for food cannot be avoided. Recruitment communication is assumed to help colonies to monopolize and exploit food sources successfully, but this has rarely been tested under field conditions. We studied if recruitment communication helps colonies of the Neotropical ant Pachycondyla harpax to be more successful in a highly competitive tropical environment. Additionally, we explored if temporal and spatial niche differentiation helps focal colonies to avoid competition. Pachycondyla harpax competed with dozens of ant species for food. Mass-recruiting competitors were often successful in displacing P. harpax from food baits. However, when foragers of P. harpax were able to recruit nestmates they had a 4-times higher probability to keep access to the food baits. Colonies were unlikely to be displaced during our observations after a few ants arrived at the food source. Competition was more intense after sunset, but a disproportionate increase in activity after sunset allowed focal colonies to exploit food sources more successfully after sunset. Our results support the hypothesis that recruitment communication helps colonies to monopolize food sources by helping them to establish a critical mass of nestmates at large resources. This indicates that even species with a small colony size and a slow recruitment method, such as tandem running, benefit from recruitment communication in a competitive environment.


Mammalia ◽  
2020 ◽  
Vol 84 (6) ◽  
pp. 503-511
Author(s):  
Hayato Takada ◽  
Riki Ohuchi ◽  
Haruko Watanabe ◽  
Risako Yano ◽  
Risako Miyaoka ◽  
...  

AbstractDifferential resource use allows for diverse species to specialize in ecological niches and thus coexist in a particular area. In the Japanese archipelago, increasing sika deer (Cervus nippon, Temminck 1836) densities have excluded the Japanese serow (Capricornis crispus, Temminck 1836), but in places where deer population densities are low, the two species coexist. We wanted to better understand their habitats and how these two ungulates manage to coexist. We evaluated the role of habitat use in the coexistence of these two sympatric ungulates on Mt. Asama, central Japan. Deer frequently used the dwarf bamboo-rich communities in autumn and winter, and their habitat use was not associated with topography. Serows frequently used deciduous broadleaf shrub-rich communities and steep slopes throughout the year. Consequently, their habitat use was significantly different in terms of vegetation and topography. Niche breadth suggests that deer tend to be generalists, whereas serows tend to be specialists. Niche differentiation in habitat use between deer and serows may make the coexistence of these similarly sized ungulates possible in Japanese mountainous zones. Therefore, the fine-grained habitat mosaic of different vegetation and topography areas might be the underlying feature that allows the coexistence of these two species.


2005 ◽  
Vol 272 (1570) ◽  
pp. 1357-1364 ◽  
Author(s):  
Lindsay A Turnbull ◽  
Liz Manley ◽  
Mark Rees

Pioneer species are fast-growing, short-lived gap exploiters. They are prime candidates for neutral dynamics because they contain ecologically similar species whose low adult density is likely to cause widespread recruitment limitation, which slows competitive dynamics. However, many pioneer guilds appear to be differentiated according to seed size. In this paper, we compare predictions from a neutral model of community structure with three niche-based models in which trade-offs involving seed size form the basis of niche differentiation. We test these predictions using sowing experiments with a guild of seven pioneer species from chalk grassland. We find strong evidence for niche structure based on seed size: specifically large-seeded species produce fewer seeds but have a greater chance of establishing on a per-seed basis. Their advantage in establishment arises because there are more microsites suitable for their germination and early establishment and not directly through competition with other seedlings. In fact, seedling densities of all species were equally suppressed by the addition of competitors' seeds. By the adult stage, despite using very high sowing densities, there were no detectable effects of interspecific competition on any species. The lack of interspecific effects indicates that niche differentiation, rather than neutrality, prevails.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yuanxing Ye ◽  
Canshi Hu ◽  
Yiting Jiang ◽  
Geoffrey W. H. Davison ◽  
Changqing Ding

Abstract Background Interspecific competition is known to be strongest between those species that are both closely related and sympatric. Egrets are colonially nesting wetland birds that often overlap and can therefore be expected to compete in roosting and nesting habitat as well as in diet. According to the niche partitioning hypothesis, it is to be expected that these similar species would show differentiation in at least one of the main niche dimensions to reduce competition. We tested niche partitioning between the colonially nesting Little Egret (Egretta garzetta) and Cattle Egret (Bubulcus ibis) in temporal, spatial and trophic dimensions. Methods Field study was conducted in three mixed egret colonies in Yangxian County, southwest Shaanxi Province, central China. For each nest colony we recorded its spatial location, the height of nesting trees and of nests, the height of roosting trees and of roosting individuals within the trees. We determined the first egg-laying and first hatching dates of the two species. Craw dissection of storm-killed egret nestlings was used to measure the diet. Six transects were surveyed to study foraging habitat selection. Results We found that hatching time of Little Egrets peaked earlier (by about 1 month) than that of Cattle Egrets. Cattle Egrets nested and roosted higher than Little Egrets. The foraging habitats used by Little Egrets were dominated by river banks (73.49%), followed by paddy fields (13.25%) and reservoirs (10.84%), whereas Cattle Egret foraging sites were characterized by grasslands (44.44%), paddy fields (33.33%) and river banks (22.22%). Little Egrets consumed more fishes (65.66%) and Odonata larvae (13.69%) than Cattle Egrets, while Cattle Egrets were found feeding mainly on Coleoptera (29.69%) and Orthoptera (23.29%). Little Egrets preyed on larger mean biomasses of food items than Cattle Egrets. Conclusions Our results confirm the niche partitioning hypothesis as a mechanism for coexistence among ecologically similar species. In two coexisting egret species, niche partitioning is multidimensional, such that the two coexistent species occupy differing ecological space based on all three temporal, spatial and trophic niche dimensions.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Christina Petalas ◽  
Thomas Lazarus ◽  
Raphael A. Lavoie ◽  
Kyle H. Elliott ◽  
Mélanie F. Guigueno

AbstractSympatric species must sufficiently differentiate aspects of their ecological niche to alleviate complete interspecific competition and stably coexist within the same area. Seabirds provide a unique opportunity to understand patterns of niche segregation among coexisting species because they form large multi-species colonies of breeding aggregations with seemingly overlapping diets and foraging areas. Recent biologging tools have revealed that colonial seabirds can differentiate components of their foraging strategies. Specifically, small, diving birds with high wing-loading may have small foraging radii compared with larger or non-diving birds. In the Gulf of St-Lawrence in Canada, we investigated whether and how niche differentiation occurs in four incubating seabird species breeding sympatrically using GPS-tracking and direct field observations of prey items carried by adults to chicks: the Atlantic puffin (Fratercula arctica), razorbill (Alca torda), common murre (Uria aalge), and black-legged kittiwake (Rissa tridactyla). Although there was overlap at foraging hotspots, all species differentiated in either diet (prey species, size and number) or foraging range. Whereas puffins and razorbills consumed multiple smaller prey items that were readily available closer to the colony, murres selected larger more diverse prey that were accessible due to their deeper diving capability. Kittiwakes compensated for their surface foraging by having a large foraging range, including foraging largely at a specific distant hotspot. These foraging habitat specialisations may alleviate high interspecific competition allowing for their coexistence, providing insight on multispecies colonial living.


2021 ◽  
Author(s):  
Julia Duerschlag ◽  
Wiebke Mohr ◽  
Timothy G. Ferdelman ◽  
Julie LaRoche ◽  
Dhwani Desai ◽  
...  

AbstractOligotrophic ocean gyre ecosystems may be expanding due to rising global temperatures [1–5]. Models predicting carbon flow through these changing ecosystems require accurate descriptions of phytoplankton communities and their metabolic activities [6]. We therefore measured distributions and activities of cyanobacteria and small photosynthetic eukaryotes throughout the euphotic zone on a zonal transect through the South Pacific Ocean, focusing on the ultraoligotrophic waters of the South Pacific Gyre (SPG). Bulk rates of CO2 fixation were low (0.1 µmol C l−1 d−1) but pervasive throughout both the surface mixed-layer (upper 150 m), as well as the deep chlorophyll a maximum of the core SPG. Chloroplast 16S rRNA metabarcoding, and single-cell 13CO2 uptake experiments demonstrated niche differentiation among the small eukaryotes and picocyanobacteria. Prochlorococcus abundances, activity, and growth were more closely associated with the rims of the gyre. Small, fast-growing, photosynthetic eukaryotes, likely related to the Pelagophyceae, characterized the deep chlorophyll a maximum. In contrast, a slower growing population of photosynthetic eukaryotes, likely comprised of Dictyochophyceae and Chrysophyceae, dominated the mixed layer that contributed 65–88% of the areal CO2 fixation within the core SPG. Small photosynthetic eukaryotes may thus play an underappreciated role in CO2 fixation in the surface mixed-layer waters of ultraoligotrophic ecosystems.


2013 ◽  
Vol 59 (6) ◽  
pp. 707-717 ◽  
Author(s):  
Solomon A. Tadesse ◽  
Burt P. Kotler

Abstract We studied the habitat use of mountain nyala Tragelaphus buxtoni in the northern edge of the Bale Mountains National Park, Ethiopia. The aims of this study were to: (1) measure and quantify habitat-specific stem bite diameters of mountain nyala foraging on common natural plant species in two major habitat types (i.e. grasslands versus woodlands), and (2) quantify the bite rates (number of bites per minute) and the activity time budgets of mountain nyala as functions of habitat type and sex-age category. We randomly laid out three transects in each habitat type. Following each transect, through focal animal observations, we assessed and quantified stem diameters at point of browse (dpb), bite rates, and time budgets of mountain nyala in grasslands versus woodlands. Stem dpb provide a measure of natural giving-up densities (GUDs) and can be used to assess foraging costs and efficiencies, with greater stem dpb corresponding to lower costs and greater efficiencies. The results showed that stem dpb, bite rates, induced vigilance, and proportion of time spent in feeding differed between habitats. In particular, mountain nyala had greater stem dpb, higher bite rates, and spent a greater proportion of their time in feeding and less in induced vigilance in the grasslands. In addition, adult females had the highest bite rates, and the browse species Solanum marginatum had the greatest stem dpb. Generally, grasslands provide the mountain nyala with several advantages over the woodlands, including offering lower foraging costs, greater safety, and more time for foraging. The study advocates how behavioural indicators and natural GUDs are used to examine the habitat use of the endangered mountain nyala through applying non-invasive techniques. We conclude that the resulting measures are helpful for guiding conservation and management efforts and could be applicable to a number of endangered wildlife species including the mountain nyala.


Sign in / Sign up

Export Citation Format

Share Document