scholarly journals Changes in niche differentiation and environmental filtering over a hydric stress gradient

2020 ◽  
Vol 13 (2) ◽  
pp. 185-194
Author(s):  
Alejandra Martínez-Blancas ◽  
Carlos Martorell
Keyword(s):  
Interspecific Competition ◽  
Interspecific Interactions ◽  
General Pattern ◽  
Stress Gradient ◽  
Niche Differentiation ◽  
Intraspecific Interactions ◽  
Soil Pathogens ◽  
Southern Mexico ◽  
Environmental Filter ◽  
Hydric Stress

Abstract Aims Diversity in communities is determined by species’ ability to coexist with each other and to overcome environmental stress that may act as an environmental filter. Niche differentiation (ND) results in stronger intra- than interspecific competition and promotes coexistence. Because stress affects interactions, the strength of ND may change along stress gradients. A greater diversity of plant growth forms has been observed in stressful habitats, such as deserts and alpine regions, suggesting greater ND when stress is strong. We tested the hypothesis that niche differences and environmental filters become stronger with stress. Methods In a semiarid grassland in southern Mexico, we sowed six annual species in the field along a hydric stress gradient. Plants were grown alone (without interactions), with conspecific neighbors (intraspecific interactions) or with heterospecific neighbors (interspecific interactions). We analyzed how the ratio of intra- to interspecific competition changed along the gradient to assess how water availability determines the strength of ND. We also determined if hydric stress represented an environmental filter. Important Findings We observed stronger intra- than interspecific competition, especially where hydric stress was greater. Thus, we found ND in at least some portion of the gradient for all but one species. Some species were hindered by stress, but others were favored by it perhaps because it eliminates soil pathogens. Although strong ND was slightly more frequent with stress, our species sample was small and there were exceptions to the general pattern, so further research is needed to establish if this is a widespread phenomenon in nature.

scholarly journals Foraging niche partitioning in sympatric seabird populations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Christina Petalas ◽  
Thomas Lazarus ◽  
Raphael A. Lavoie ◽  
Kyle H. Elliott ◽  
Mélanie F. Guigueno
Keyword(s):  
Interspecific Competition ◽  
Niche Partitioning ◽  
Niche Differentiation ◽  
Sympatric Species ◽  
Foraging Strategies ◽  
Gps Tracking ◽  
Seabird Species ◽  
Foraging Range ◽  
Common Murre ◽  
Prey Items

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.

scholarly journals Do syntopic host species harbour similar symbiotic communities? The case ofChaetopterusspp. (Annelida: Chaetopteridae)

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e2930 ◽  
Author(s):  
Temir A. Britayev ◽  
Elena Mekhova ◽  
Yury Deart ◽  
Daniel Martin
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Host Species ◽  
Interspecific Interactions ◽  
Single Species ◽  
Intraspecific Interactions ◽  
Mean Intensity ◽  
Species Dominance ◽  
High Species Richness ◽  
Symbiotic Community

To assess whether closely related host species harbour similar symbiotic communities, we studied two polychaetes,Chaetopterussp. (n = 11) andChaetopteruscf.appendiculatus(n = 83) living in soft sediments of Nhatrang Bay (South China Sea, Vietnam). The former harboured the porcellanid crabsPolyonyxcf.heokandPolyonyxsp., the pinnotherid crabTetriassp. and the tergipedid nudibranchPhestillasp. The latter harboured the polynoid polychaeteOphthalmonoe pettiboneae, the carapid fishOnuxodon fowleriand the porcellanid crabEulenaios cometes, all of which, exceptO. fowleri, seemed to be specialized symbionts. The species richness and mean intensity of the symbionts were higher inChaetopterussp. than inC.cf.appendiculatus(1.8 and 1.02 species and 3.0 and 1.05 individuals per host respectively). We suggest that the lower density ofChaetopterussp. may explain the higher number of associated symbionts observed, as well as the 100% prevalence (69.5% inC.cf.appenciculatus). MostChaetopterussp. harboured two symbiotic species, which was extremely rare inC.cf.appendiculatus, suggesting lower interspecific interactions in the former. The crab and nudibranch symbionts ofChaetopterussp. often shared a host and lived in pairs, thus partitioning resources. This led to the species coexisting in the tubes ofChaetopterussp., establishing a tightly packed community, indicating high species richness and mean intensity, together with a low species dominance. In contrast, the aggressive, strictly territorial species associated withC.cf.appendiculatusestablished a symbiotic community strongly dominated by single species and, thus, low species richness and mean intensity. Therefore, we suggest that interspecific interactions are determining species richness, intensity and dominance, while intraspecific interactions are influencing only intensity and abundance. It is possible that species composition may have influenced the differences in community structure observed. We hypothesize that both host species could originally be allopatric. The evolutionary specialization of the symbiotic communities would occur in separated geographical areas, while the posterior disappearance of the existing geographical barriers would lead to the overlapped distribution.

Habitat use and coexistence of three territorial herbivorous damselfish on different-size patch reefs

2013 ◽  
Vol 93 (8) ◽  
pp. 2265-2272 ◽  
Author(s):  
Akihisa Hattori ◽  
Takuro Shibuno
Keyword(s):  
Species Richness ◽  
Habitat Use ◽  
Interspecific Interactions ◽  
Patch Reef ◽  
Back Reef ◽  
Intraspecific Interactions ◽  
Reef Area ◽  
Patch Reefs ◽  
Significant Difference ◽  
Random Placement

In local reef fish communities, species richness increases with increasing reef area. At Ishigaki Island, Japan, species richness is much lower on large reefs in the shallow back reef than that expected from random placement model simulations (RPMS). As three aggressive territorial herbivorous damselfish, Stegastes nigricans, Stegastes lividus and Hemiglyphidodon plagiometopon, coexist only on such large reefs, we focused on these species and examined patterns of their distribution and abundance on 84 patch reefs of various sizes (area and height). We also examined their aggressive intra- and interspecific behavioural interactions and habitat use on the two large reefs (the largest complex patch reef and the large flat patch reef) among the 84 patch reefs. While the abundance of both S. lividus and H. plagiometopon was highly correlated with patch reef area, that of S. nigricans was closely correlated with patch reef height. For S. nigricans and S. lividus, interspecific interactions occurred significantly more frequently than intraspecific interactions on the large flat patch reef. However, there was no significant difference in frequencies of the two interaction types on the largest complex patch reef, where they three-dimensionally segregated conspecific territories. This study suggested that reef height as well as reef area influence the distribution and abundance of these territorial herbivorous damselfish in the shallow back reef. As large patch reefs cannot be tall allometrically in shallow back reefs, relatively flat patch reefs may not have the high species richness expected from RPMS based on reef area.

scholarly journals Coexistence of surface and cave amphipods in an ecotone environment

2011 ◽  
Vol 80 (2) ◽  
pp. 133-141 ◽  
Author(s):  
Roman Luštrik ◽  
Martin Turjak ◽  
Simona Kralj-Fišer ◽  
Cene Fišer
Keyword(s):  
Leaf Litter ◽  
Species Interactions ◽  
Interspecific Interactions ◽  
Habitat Choice ◽  
Intraspecific Interactions ◽  
Size Dependent ◽  
Predation Effects ◽  
Similar Body ◽  
Subterranean Species

Interspecific interactions between surface and subterranean species may be a key determinant for species distributions. Until now, the existence of competition (including predation) between these groups has not been tested. To assess the coexistence and potential role of interspecific interactions between surface Gammarus fossarum and subterranean Niphargus timavi, and to determine their micro distributions, we conducted a series of field and laboratory observations. We aimed to determine: (1) species substrate preference, (2) whether the presence of G. fossarum influences the habitat choice of N. timavi, and (3) possible predation effects on micro habitat choice of small juveniles. Throughout a small river in SW Slovenia, N. timavi was predominantly found in leaf litter and gravel, but rarely in sand. In the sand however, we exclusively found juveniles. In contrast, surface G. fossarum sheltered mainly in leaf litter. A similar, body size dependent, micro distribution was observed in G. fossarum, where small individuals were generally found in gravel and sand. The presence of G. fossarum affected the micro distribution of juvenile, but not adult, N. timavi. In the laboratory we observed predation and cannibalism in both species. Niphargus timavi, however, appeared to be a more efficient predator than G. fossarum. In particular, juvenile N. timavi were most vulnerable to preying by adults of both species. This probably affected the distribution of juvenile N. timavi that chose finer substrates when placed with adult individuals in an aquarium with granules of different size. To understand the distribution of subterranean species, the summed effect of intraspecific interactions, as well as surface – subterranean species interactions, in particular between individuals of different size, should be taken into account.

Effect of nitrate supply on the facilitation between two salt-marsh plants (Suaeda salsa and Scirpus planiculmis)

2020 ◽  
Vol 13 (2) ◽  
pp. 204-212
Author(s):  
Hua Ma ◽  
Li-Juan Cui ◽  
Xu Pan ◽  
Wei Li ◽  
Yu Ning ◽  
...  
Keyword(s):  
Salt Marsh ◽  
Plant Species ◽  
Salt Marshes ◽  
Interspecific Interactions ◽  
Stress Gradient ◽  
Interactive Effects ◽  
Suaeda Salsa ◽  
Environmental Drivers ◽  
Salt Marsh Plant ◽  
Nitrate Supply

Abstract Aims In estuarine salt-marshes, nitrate supply and soil salinity, which are known as two main environmental drivers, simultaneously affect the interspecific interactions between plant species. However, to date, their interactive effects on interspecific interactions have not been closely examined for salt-marsh plant species. Methods Juvenile plants of Suaeda salsa L. (Chenopodiaceae) and Scirpus planiculmis Fr. (Cyperaceae) were grown in rinsed river sand to conduct a greenhouse experiment with three treatment categories: interspecific interaction (mixed culture or monoculture), three salinity levels (1, 50 and 100 mmol L−1) and three nitrate levels (0.5, 5 and 10 mmol L−1). First, height and biomass of all plants were measured. Then, the growth data, relative interaction index and competitive important index of the two species were analyzed. Important Findings The interspecific interactions between S. salsa and S. planiculmis were facilitation across the salinity gradients. The promotion of S. salsa growth with high nitrate supply did not enhance the facilitative effect of the species, especially at low salinity. However, high nitrate supply significantly shifted the interspecific interactions of S. planiculmis from facilitation to competition at high salinity. Our results suggest that excessive nitrate application changes the prediction of the stress-gradient hypothesis along a salinity gradient, leading to collapse of the two species coexistence in the salt-marshes. These findings make a contribution to the understanding of how S. salsa and S. planiculmis, as well as salt-marsh communities, respond to the human modification of estuarine nutritional levels.

Interspecific and intraspecific interactions in the monogenean communities of fish: a question of study scale?

Parasitology ◽  
2007 ◽  
Vol 134 (9) ◽  
pp. 1237-1242 ◽  
Author(s):  
A. KARVONEN ◽  
A. M. BAGGE ◽  
E. T. VALTONEN
Keyword(s):  
Crucian Carp ◽  
Competitive Exclusion ◽  
Interspecific Interactions ◽  
Species Level ◽  
Small Scale ◽  
Carassius Carassius ◽  
Intraspecific Interactions ◽  
Mate Finding ◽  
Gill Filaments ◽  
High Parasite

SUMMARYMonogenean communities of fish have generally been considered non-interactive as negative interspecific interactions have rarely been reported. Most of the earlier studies on monogenean communities, however, have been conducted not only in systems with relatively low parasite abundances but, more importantly, at study scales where microhabitat-level interactions between the parasites are easily overlooked. We examined the communities of 3 abundant Dactylogyrus (Monogenea) species on the gills of crucian carp (Carassius carassius) by analysing the interactions at the scale of individual gill filaments, where interactions between the species, if any, should most likely take place. Contrary to our expectations, we did not find evidence for competitive exclusion between the species, which suggests that monogenean communities are non-interactive even in high parasite abundances. At the species level, individual parasites were highly aggregated within the filaments, essentially showing a strong tendency to occur at either end of a filament. This, together with the result of differences in the distribution of juvenile parasites within the filaments compared to adults, suggests that these parasites are able to actively seek out their conspecifics in small-scale microhabitats during maturation, which again could enhance their mate-finding.

Multivariate Time Series Analysis of the Canadian Fisheries System in Lake Superior

1987 ◽  
Vol 44 (S2) ◽  
pp. s171-s181 ◽  
Author(s):  
Y. Cohen ◽  
J. N. Stone
Keyword(s):  
Time Series ◽  
Fish Species ◽  
Lake Trout ◽  
Interspecific Interactions ◽  
Lake Superior ◽  
Multivariate Time Series ◽  
Policy Decision ◽  
Trophic Relationships ◽  
Catch Per Unit Effort ◽  
Intraspecific Interactions

Data for the Canadian fisheries system in Lake Superior were organized into monthly time series of catch and effort from January 1963 through December 1976 for six fish species. Multivariate, autoregressive (ARMA) models were identified for the system based on data for the first 140 mo. Forecasts were compared to data for the last 28 mo. The structure of the models indicate that (1) within the system, AR processes, as opposed to MA processes, were of overriding importance, (2) intraspecific interactions (inferred from data on catch-per-unit-effort, CPUE) were more prevalent than interspecific interactions, (3) interactions within the system occurred with lags of 1, 4, 12, 24, 25, 28, and 36 mo, (4) some of the trophic relationships among the fish species were revealed by the models, and (5) CPUE time series of lake trout (Salvelinus namaycush) affected, but was not affected by, the CPUE time series of other species. The models were used to forecast catch and CPUE for the last 28 mo, and the data were generally within one standard error of the forecasts. The models may help policy decision makers to explore the effects of inputs (e.g. quota regulations) and feedbacks within the fisheries' system on outputs (e.g. production, CPUE).

scholarly journals A general model of population dynamics accounting for multiple kinds of interaction

2020 ◽  
Author(s):  
Luciano Stucchi ◽  
Juan Manuel Pastor ◽  
Javier García-Algarra ◽  
Javier Galeano
Keyword(s):  
Population Dynamics ◽  
Interspecific Interactions ◽  
Order Term ◽  
Complex Model ◽  
Equilibrium Solutions ◽  
Intraspecific Interactions ◽  
Intraspecific Interaction ◽  
Population Dynamics Models ◽  
Dynamics Models ◽  
Simple Picture

ABSTRACTPopulation dynamics has been modelled using differential equations almost since Malthus times, more than two centuries ago. Basic ingredients of population dynamics models are typically a growth rate, a saturation term in the form of Verhulst’s logistic brake, and a functional response accounting for interspecific interactions. However intraspecific interactions are not usually included in the equations. The simplest models use linear terms to represent a simple picture of the nature, meanwhile to represent more complex landscapes, it is necessary to include more terms with higher order or analytically more complex. The problem to use a simpler or more complex model depends on many factors: mathematical, ecological, or computational. To address it, here we discuss a new model based on a previous logistic-mutualistic model. We have generalised the interspecific terms (for antagonistic and competitive relationships) and we have also included new polynomial terms to explain any intraspecific interaction. We show that by adding simple intraspecific terms, new free-equilibrium solutions appear driving a much richer dynamics. These new solutions could represent more realistic ecological landscapes by including a new high order term.

Habitat and nest-site partitioning in splendid and variegated fairy-wrens (Aves : Maluridae)

1999 ◽  
Vol 47 (4) ◽  
pp. 317 ◽  
Author(s):  
Elizabeth Tibbetts ◽  
Stephen Pruett-Jones
Keyword(s):  
Life History ◽  
Habitat Use ◽  
Interspecific Competition ◽  
Similar Pattern ◽  
Foraging Behaviour ◽  
Nest Site ◽  
Interspecific Interactions ◽  
Territory Size ◽  
Sympatric Populations ◽  
Nest Placement

Territory size, interspecific interactions, foraging behaviour, habitat use, and nest placement were examined in sympatric populations of splendid (Malurus splendens melanotus) and variegated (M. lamberti assimilis) fairy-wrens. Although these species have similar patterns of life history and biology, they utilise different microhabitats within overlapping territories. Splendid fairy-wrens spent more time on the ground and in open areas, whereas variegated fairy-wrens generally preferred higher and more protected locations. The two species exhibited a similar pattern of separation with respect to foraging behaviour, as splendid fairy- wrens mainly foraged on the ground whereas variegated fairy-wrens preferred bushes. They also partitioned nesting habitat, with splendid fairy-wrens building nests in areas with a greater density of trees than variegated fairy-wrens. Further, splendid fairy-wrens built nests in larger shrubs and farther from the edge of these bushes than variegated fairy-wrens. We suggest that these differences in habitat use decrease interspecific competition between the two species.

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