Food-niche relationships and guild structure of diurnal birds of prey: competition versus opportunism

1983 ◽  
Vol 61 (10) ◽  
pp. 2230-2241 ◽  
Author(s):  
Fabian M. Jaksić ◽  
H. Elizabeth Braker
Keyword(s):  
Niche Breadth ◽  
Niche Overlap ◽  
Single Species ◽  
Feeding Guilds ◽  
Guild Structure ◽  
Food Size ◽  
Food Niche ◽  
Very High ◽  
Opportunistic Feeding ◽  
Niche Relationships

Food-niche relationships of diurnal raptors have been claimed to be shaped by either competitive interactions or opportunistic feeding. We confront these alternatives by analyzing the patterns of prey use of five assemblages of falconiforms. Our results show that food-niche breadth is not a species property but is determined by the food resources locally available; neither does it become narrower in larger assemblages nor is it correlated with raptor size. Food-niche overlaps are frequently very high and do not become smaller in larger assemblages. Mean weight of prey taken is positively correlated with raptor weight within assemblages, but varies widely across assemblages, with a single species showing manyfold differences. Weight ratios between raptors contiguous in the size axis fall well below the 2.2–3.4 expected figures, nor are they negatively correlated with the amount of food-niche overlap. Normalized distance ratios (d/w) of spacing between raptors along the food-size axis are usually smaller than the expected 1. The five assemblages are organized in feeding guilds whose size is larger where fewer prey categories are available per raptor species. In most cases we found little support for predictions based on competition-structured assemblages. This is probably because of the opportunistic feeding behavior of raptors, and perhaps also because food might not be a limiting resource for them.

scholarly journals Investigating Carnivore Guild Structure: Spatial and Temporal Relationships amongst Threatened Felids in Myanmar

2021 ◽  
Vol 10 (12) ◽  
pp. 808
Author(s):  
Pyae Phyoe Kyaw ◽  
David W. Macdonald ◽  
Ugyen Penjor ◽  
Saw Htun ◽  
Hla Naing ◽  
...  
Keyword(s):  
Resource Competition ◽  
Niche Overlap ◽  
Single Species ◽  
Temporal Association ◽  
Guild Structure ◽  
Mesopredator Release ◽  
Temporal Dimension ◽  
Temporal Behaviour ◽  
Niche Differences ◽  
Spatio Temporal

The co-occurrence of felid species in Southeast Asia provides an unusual opportunity to investigate guild structure and the factors controlling it. Using camera-trap data, we quantified the space use, temporal activity, and multi-dimensional niche overlap of the tiger, clouded leopard, Asiatic golden cat, marbled cat, and leopard cat in the Htamanthi Wildlife Sanctuary, Myanmar. We hypothesised that the spatio-temporal behaviour of smaller cats would reflect the avoidance of the larger cats, and similar-sized guild members would partition their niches in space or time to reduce resource competition. Our approach involved modelling single-species occupancy, pairwise spatial overlap using Bayesian inference, activity overlap with kernel density estimation, and multivariate analyses. The felid assembly appeared to be partitioned mainly on a spatial rather than temporal dimension, and no significant evidence of mesopredator release was observed. Nonetheless, the temporal association between the three mesopredators was inversely related to the similarity in their body sizes. The largest niche differences in the use of space and time occurred between the three smallest species. This study offers new insight into carnivore guild assembly and adds substantially to knowledge of five of the least known felids of conservation concern.

scholarly journals Investigating carnivore guild structure: Spatial and temporal relationships amongst threatened felids in Myanmar

2020 ◽  
Author(s):  
Pyae Kyaw ◽  
David Macdonald ◽  
Ugyen Penjor ◽  
Saw Htun ◽  
Hla Naing ◽  
...  
Keyword(s):  
Niche Overlap ◽  
Single Species ◽  
Temporal Association ◽  
Guild Structure ◽  
Mesopredator Release ◽  
Occupancy Modelling ◽  
Temporal Dimension ◽  
Temporal Behaviour ◽  
Clouded Leopard ◽  
Leopard Cat

At least nine felid species can co-occur in Southeast Asia, thus providing an unusual opportunity to investigate poorly known guild structure and the factors controlling it. Using camera-trap data, we quantified space use, temporal activity, and multi-dimensional niche overlap of tiger, clouded leopard, marbled cat, leopard cat, and Asiatic golden cat in Htamanthi Wildlife Sanctuary of Myanmar. We hypothesized that the spatio-temporal behaviour of smaller cats can reflect avoidance of the larger cats, which are both potential competitors and predators, and similar-sized guild members would partition their niches in space or time to reduce competition for resources. Our approach involved single-species occupancy modelling to identify site covariates, pairwise spatial overlap using Bayesian inference, and activity overlap with Kernel density estimation and multivariate analyses to test hypotheses. We found tiger and marbled cats were primarily diurnal, clouded leopard and leopard cat were nocturnal and golden cat exhibited cathemeral activity. We observed a complex pattern of guild assembly and potential competition involving strong niche displacement between the golden cat and marbled cat, but high overlap between the relatively similarly-sized pairing of clouded leopard and golden cat, and the markedly differently-sized tiger – golden cat pairing. No significant evidence of mesopredator release was observed and the felid assembly in Northern Myanmar appeared to be partitioned mainly on a spatial, rather than temporal, dimension. Nonetheless, the temporal association between the three mesopredators was inversely related to the similarity in their body sizes. The insights into this felid guild revealed that the largest niche differences in the use of space and time occurred between the three smaller species, most evidently between the Asiatic golden cat-marbled cat pairing, followed by marbled cat - leopard cat pairing. This study offers new insight into carnivore guild assembly and, adds substantially to knowledge of five of the least known felids of conservation concern.

scholarly journals The impact of Sosnowsky’s Hogweed on feeding guilds of birds

2021 ◽  
Author(s):  
Emilia Grzędzicka ◽  
Jiří Reif
Keyword(s):  
Negative Impact ◽  
Bird Community ◽  
Plant Invasions ◽  
Bird Communities ◽  
Feeding Guilds ◽  
Guild Structure ◽  
Feeding Guild ◽  
Potential Impact ◽  
Underlying Mechanisms ◽  
The Impact

AbstractPlant invasions alter bird community composition worldwide, but the underlying mechanisms still require exploration. The investigation of feeding guild structure of bird communities can be informative in respect to the potential impact of invasion features on the availability of food for birds. For this purpose, we focused on determining the influence of the invasive Sosnowsky’s Hogweed Heracleum sosnowskyi on the abundance of birds from various feeding guilds. In spring and summer 2019, birds were counted three times on 52 pairs of sites (control + Heracleum) in southern Poland, at various stages of Sosnowsky’s Hogweed development (i.e. sprouting, full growth and flowering, all corresponding to respective bird counts). We have shown that the presence of invader negatively affected the abundance of birds from all feeding guilds. However, a closer examination of the invaded sites uncovered that responses of particular guilds differed in respect to development stages expressed by a set of characteristics of the invader. Ground and herb insectivores were more common on plots with a higher number of the invader, while the abundance of bush and tree insectivores was negatively correlated with hogweeds’ height. Granivores were not affected by the invader’s features, while the abundance of omnivores was negatively related to the number of flowering hogweeds. Besides showing the general negative impact of the invader on different feeding guilds, our research has shown that certain aspects of Sosnowsky’s Hogweed invasion may support or depress occurrence of different birds on invaded plots. Knowledge of these aspects may facilitate our capacity for coping with challenges the invasive plants put in front of bird conservationists.

scholarly journals Ecology of colonizing populations of the figfly Zaprionus indianus (Diptera, Drosophilidae) in Porto Alegre, Southern Brazil

2005 ◽  
Vol 95 (3) ◽  
pp. 233-240 ◽  
Author(s):  
Norma Machado da Silva ◽  
Carina da Conceição Fantinel ◽  
Vera Lucia da Silva Valente ◽  
Vitor Hugo Valiati
Keyword(s):  
Niche Breadth ◽  
Niche Overlap ◽  
Trophic Niche ◽  
Survival Strategies ◽  
Porto Alegre ◽  
Zaprionus Indianus ◽  
Feeding Sites ◽  
Substrate Choice ◽  
Oviposition Substrate ◽  
Feeding Substrate

Ecological parameters such as trophic niche overlap and niche breadth were computed from the frequency of all drosophilid species collected in 2001 and 2002, in the urban area of Porto Alegre city, Brazil. Independently of place, drosophilids community composition and components breeding or feeding sites, the highest frequencies of Zaprionus indianus (Gupta, 1970) were obtained during seasons with higher average temperatures, especially during summer. From a total of the 19,146 individuals of Z. indianus sampled, 80% were found in this season. The data of trophic niche breadth suggest a higher opportunism of adult flies in feeding substrate use, but the females are still selective in oviposition substrate choice. For the values of niche overlap, only for some species, did we find any correlation between these and species richness and/or number of resources, and the most of the correlation values considering breeding and feeding sites were positive. The colonization of Z. indianus in Porto Alegre could be leading to adjustments in the survival strategies of the resident species, but it is possible that many species have conditions for coexisting with the invader.

scholarly journals Trophic interactions among sympatric zooplanktivorous fish species in volume change conditions in a large, shallow, tropical lake

2011 ◽  
Vol 9 (1) ◽  
pp. 169-176 ◽  
Author(s):  
Rodrigo Moncayo-Estrada ◽  
Owen T Lind ◽  
Carlos Escalera-Gallardo
Keyword(s):  
Niche Breadth ◽  
Temporal Distribution ◽  
Niche Overlap ◽  
Species Interaction ◽  
Trophic Relationships ◽  
Water Volume ◽  
Species Flock ◽  
Small Range ◽  
Mean Values ◽  
Significant Difference

Significant reductions in the water volume of shallow lakes impose a restriction on species segregation promoting more interactions in the trophic relationships. The diets of three closely related zooplanktivorous silversides belonging to the Atherinopsidae species flock of lake Chapala , Mexico, were analyzed at two sites (Chirostoma jordani, C. labarcae, and C. consocium). Diets were described in critical shallow (August 2000) and volume recovery conditions (August 2005). Diets included mainly cladocerans (Bosmina, Ceriodaphnia, and Daphnia) and copepods (Cyclops). A significant difference in diets was detected when comparing years (MRPP analysis, A = 0.22, p < 0.0001) and sites at different years (MRPP analysis, A = 0.17, p = 0.004). According to niche breadth mean values, species were classified as specialized and intermediate feeders. In shallow conditions, the small range of niche breadth (1.72 to 3.64) and high diet overlap values (D = 0.64, L = 8.62) indicated a high potential for interspecific exploitative interaction. When the lake volume recovered, an increase in the niche breadth range (1.04 to 4.96) and low niche overlap values (D = 0.53, L = 2.32) indicated a reduction of the species interaction. The Mann-Whitney U-test supported this pattern by showing a significant difference between years for niche overlap (p = 0.006). The increased interaction during the low volume suggests alternative segregation in life-history variations and other niche dimensions such as spatial or temporal distribution.

Summer food composition and food niche overlap of the raccoon dog, red fox and badger in Finland

Ecography ◽  
1998 ◽  
Vol 21 (5) ◽  
pp. 457-463 ◽  
Author(s):  
Kaarina Kauhala ◽  
Paula Laukkanen ◽  
Inez Rége
Keyword(s):  
Red Fox ◽  
Niche Overlap ◽  
Food Composition ◽  
Raccoon Dog ◽  
Food Niche

Diets of three sympatric Neotropical small cats: Food niche overlap and interspecies differences in prey consumption

2011 ◽  
Vol 76 (3) ◽  
pp. 308-312 ◽  
Author(s):  
José E. Silva-Pereira ◽  
Rodrigo F. Moro-Rios ◽  
Diego R. Bilski ◽  
Fernando C. Passos
Keyword(s):  
Niche Overlap ◽  
Prey Consumption ◽  
Interspecies Differences ◽  
Food Niche

scholarly journals Wetland selection, niche breadth and overlap in 10 duck species wintering in northern Campania (Italy)

2018 ◽  
Vol 87 (2) ◽  
pp. 3-8
Author(s):  
Stefano Giustino ◽  
Marcello Bruschini ◽  
Elio Esse ◽  
Silvana Grimaldi ◽  
Danila Mastronardi ◽  
...  
Keyword(s):  
Niche Breadth ◽  
Selection Index ◽  
Niche Overlap ◽  
Campania Region ◽  
Duck Species ◽  
Wintering Area ◽  
Morisita Index ◽  
Species Preferences

Analysis of the selection index, the niche breadth and the niche overlap of 10 species of wintering ducks in 11 wetland areas of the Campania region between January 2003 and 2015 revealed that the distribution of the species in the examined sites was not casual. In fact, each species actively chose their wintering area. Using selection index, we were able to measure the species’ preferences and non-preferences for the 11 examined sites. By calculating Shannon-Wiener entropy and its normalized value (Evenness), we determined niche breadth; the Morisita index allowed us to check niche overlap.

Assessing the diet and trophic niche breadth of an omnivorous fish (Glanidium ribeiroi) in subtropical lotic environments: intraspecific and ontogenic responses to spatial variations

2019 ◽  
Vol 70 (8) ◽  
pp. 1116 ◽  
Author(s):  
B. C. K. Kliemann ◽  
M. C. Baldasso ◽  
S. F. R. Pini ◽  
M. C. Makrakis ◽  
S. Makrakis ◽  
...  
Keyword(s):  
Forest Cover ◽  
Agricultural Land ◽  
Niche Breadth ◽  
Intraspecific Variability ◽  
Niche Overlap ◽  
Trophic Niche ◽  
Main Channel ◽  
Size Classes ◽  
Intraspecific Variations ◽  
Environmental Variations

The diet of Glanidium ribeiroi was investigated in lotic stretches downstream from a cascade of reservoirs to determine how it responds to intraspecific and environmental variations. Monthly sampling was performed from 2013 to 2016 at sites including the main channel of the Iguaçu River and tributaries in preserved basins and agricultural land. The diet of individuals in the preserved tributaries was primarily associated with allochthonous resources, whereas in the non-preserved tributaries and main channel the diets were primarily associated with autochthonous resources. Trophic niche breadth and intraspecific variability differed significantly among sampling areas and size classes. Trophic niche overlap among size classes and sampling areas was low. Positive and negative relationships between the trophic niche breadth and the standard length of individuals were also found in different sampling areas. Intraspecific and ontogenic variations were strongly and consistently associated with forest cover. Individuals responded differently to local environmental variations due to differences in landscape gradients and life cycle changes. Therefore, the effects of spatial heterogeneity on diet composition and intraspecific variations therein appear to be crucial to the success of the populations evaluated. These results may help with the implementation of conservation measures for this and other endemic species.

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