scholarly journals Alligator presence influences colony site selection of long-legged wading birds through large scale facilitative nest protector relationship

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wray Gabel ◽  
Peter Frederick ◽  
Jabi Zabala

AbstractPositive ecological relationships, such as facilitation, are an important force in community organization. The effects of facilitative relationships can be strong enough to cause changes in the distributions of species and in many cases have evolved as a response to predation pressure, however, very little is known about this potential trend in vertebrate facilitative relationships. Predation is an important selective pressure that may strongly influence breeding site selection by nesting birds. The American Alligator (Alligator mississippiensis) facilitates a safer nesting location for wading birds (Ciconiiformes and Pelecaniformes) by deterring mammalian nest predators from breeding sites. However, alligators do not occur throughout the breeding range of most wading birds, and it is unclear whether alligator presence affects colony site selection. We predicted that nesting wading birds change colony site preferences when alligators are not present to serve as nest protectors. Within the northern fringe of alligator distribution we compared colony characteristics in locations where alligator presence was either likely or unlikely while controlling for availability of habitat. Wading birds preferred islands that were farther from the mainland and farther from landmasses > 5 ha when alligator presence was unlikely compared to when alligators were likely. These findings indicate that wading birds are seeking nesting locations that are less accessible to mammalian predators when alligators are not present, and that this requirement is relaxed when alligators are present. This study illustrates how a landscape-scale difference between realized and fundamental niche can result from a facilitative relationship in vertebrates.

2014 ◽  
Vol 71 (10) ◽  
pp. 1498-1507 ◽  
Author(s):  
Steven M. Clark ◽  
Jason B. Dunham ◽  
Jeffrey R. McEnroe ◽  
Scott W. Lightcap

The fitness of female Pacific salmon (Oncorhynchus spp.) with respect to breeding behavior can be partitioned into at least four fitness components: survival to reproduction, competition for breeding sites, success of egg incubation, and suitability of the local environment near breeding sites for early rearing of juveniles. We evaluated the relative influences of habitat features linked to these fitness components with respect to selection of breeding sites by coho salmon (Oncorhynchus kisutch). We also evaluated associations between breeding site selection and additions of large wood, as the latter were introduced into the study system as a means of restoring habitat conditions to benefit coho salmon. We used a model selection approach to organize specific habitat features into groupings reflecting fitness components and influences of large wood. Results of this work suggest that female coho salmon likely select breeding sites based on a wide range of habitat features linked to all four hypothesized fitness components. More specifically, model parameter estimates indicated that breeding site selection was most strongly influenced by proximity to pool-tail crests and deeper water (mean and maximum depths). Linkages between large wood and breeding site selection were less clear. Overall, our findings suggest that breeding site selection by coho salmon is influenced by a suite of fitness components in addition to the egg incubation environment, which has been the emphasis of much work in the past.


2007 ◽  
Vol 34 (1) ◽  
pp. 59 ◽  
Author(s):  
M. Semeniuk ◽  
F. Lemckert ◽  
R. Shine

Previous research on cane toads (Bufo marinus) has documented non-random selection of breeding sites by this invasive species. In the wet–dry tropics of the Northern Territory, toads selected spawning sites in open areas with gently sloping banks and shallow water. If consistent, such biases may present opportunities for toad control via waterbody manipulation – but first we need to know whether such criteria for spawning-site selection (1) are consistent across other parts of the toad’s extensive Australian range, and (2) differ from those of native anurans breeding at the same waterbodies. We quantified the attributes of potential and actual spawning-sites in north-eastern New South Wales, in temperate-zone habitat where cane toads have been present for many decades; our study area thus differs in many ways from the previously studied tropical site. We compared habitat and water chemistry variables between 23 cane toad breeding sites and 23 nearby unused sites. To examine habitat use at an even finer scale, we conducted nocturnal surveys of microhabitat use by calling male toads and native anurans. Our results revealed that cane toads in this region were highly selective in their choice of breeding sites, and that the criteria they used in this respect were similar to those used by toads in the Northern Territory. Calling male cane toads also used microhabitats non-randomly within each pond, apparently based on similar criteria to those used when selecting among ponds. Toads differed significantly from native anurans in these respects, suggesting that it may be feasible to manipulate waterbody attributes to impact on invasive toads without disrupting reproduction by native anurans.


2011 ◽  
Vol 32 (1) ◽  
pp. 105-112 ◽  
Author(s):  
Gerardo Leynaud ◽  
Julián Lescano ◽  
Laura Pereyra

AbstractDifferences among wetlands can have important consequences on reproductive success of amphibians; therefore habitat selection is expected to be of particular importance for anurans inhabiting heterogeneous environments. To investigate if the red-belly toad (Melanophryniscus stelzneri; Anura: Bufonidae) uses available habitats differentially and to determine the main factors influencing the use of certain water bodies as breeding habitat, we surveyed 30 spawning sites used by red-belly toads, and 30 adjacent unused sites, in an area of the Sierras of Córdoba, Argentina. We evaluated the relative importance of morphological and biotic features of ponds, and the presence of other organisms within the water body on the use of ponds as breeding sites by red-belly toads. Eight habitat variables related to important water body features were recorded and were used to fit a habitat selection model with GLM. Red-belly toads presented a positive selection to mallines, a wetland characteristic of the Sierras of Córdoba. They were associated with small, shallow ephemeral ponds with muddy banks and a high percent of vegetation cover. In general, the ponds used did not host other anuran species or potential predators. Breeding site selection by red-belly toads is largely consistent with records for other species of the genus in other parts of Argentina.


2016 ◽  
Vol 25 (12) ◽  
pp. 1281 ◽  
Author(s):  
Anna Weier ◽  
Ian J. Radford ◽  
Sofia L. J. Oliveira ◽  
Michael J. Lawes

Frequent and extensive fires are becoming increasingly common throughout the tropical savannas of northern Australia. This fire regime has been implicated in both habitat alteration and losses of biodiversity. Granivorous birds are particularly affected because of the effect of fire on grass seed availability. The endemic Gouldian finch (Erythrura gouldiae) has experienced population declines in recent decades, potentially in response to changed fire regimes. Using breeding data from monitored artificial nest-boxes, this study examined the choice of breeding site by Gouldian finches in response to several attributes of the prevailing fire regime. The fire regime was characterised using remote sensing analysis of annual fire scars. Time since last fire and fire frequency were the most useful predictors of breeding site occupancy. Gouldian finches favoured recently burnt sites (previous dry season), but also sites that were infrequently burnt (return time of 2–3 years). Consequently, under the current regime of many frequent fires, Gouldian finches move among breeding sites and display low seasonal site fidelity. Our findings provide support for the notion that the Gouldian finch favours a fine-grain patch-mosaic fire regime and that contemporary large-scale fire regimes are likely contributing to their decline.


2017 ◽  
Vol 39 (2) ◽  
pp. 161 ◽  
Author(s):  
Bradley Smith ◽  
Anne-Louise Vague

Little is known about reproduction and den site selection by free-ranging dingoes. We present observations of den sites used by dingoes inhabiting a large-scale mining operation located in the Great Sandy Desert, Western Australia. We observed 24 dens concentrated within a 1-km radius. Den sites were generally situated in elevated positions overlooking the surrounding area, were a short distance from food and water resources, required vegetation (particularly spinifex grass) to provide a firm foundation and stable ceiling in the soft sand, and had single den openings that faced away from the rising and daytime sun. Distance to human structures or activity did not appear to influence site selection. Four of the dens were active, containing a total of 37 pups aged between two and four weeks of age. One den contained 18 pups of different ages, indicating that communal denning was also occurring. The high number of breeding females within close proximity suggests that multiple family groups are able to share resources and live in close proximity. Our findings highlight the importance of human-modified areas and abundance of resources in the reproduction and breeding site selection of dingoes.


2020 ◽  
Vol 3 (5) ◽  
pp. 100-107
Author(s):  
Marina Camargo de Sousa ◽  
◽  
Julia Ronzani Vial ◽  
Rodrigo Hidalgo Friciello Teixeira ◽  
Andrea Cristina Higa Nakaghi ◽  
...  

Birds of the psittaciform order, composed by the Psittacidae and Loridae family have several characteristics making them more frequently kept as companion animals, promoting the increase of breeding sites in Brazil. The present study aimed to analyze the specificity and sensitivity of three different coproparasitological tests, Willis, Hoffman and Direto de feces, through statistical tests: Chi-Square and Kappa. 70 fecal samples of exotic parrots were collected from a commercial breeding site and these were submitted to the three tests, totaling 210 coproparasitological exams. Among the tests performed, 29,5% were positive for nematode eggs, cestodes and oocysts. Coproparasitological exams are inexpensive, have clinical importance, indicating the population of endoparasites and therapeutic treatments.


2013 ◽  
Vol 29 (2) ◽  
pp. 357-367 ◽  
Author(s):  
Onicio Batista Leal Neto ◽  
Elainne Christine de Souza Gomes ◽  
Fernando José Moreira de Oliveira Junior ◽  
Rafael Andrade ◽  
Diego Leandro Reis ◽  
...  

Schistosomiasis has expanded to the coast of Pernambuco State, Brazil, where there are frequent reports of Biomphalaria glabrata snails and human cases of the disease. This study analyzes factors related to schistosomiasis transmission risk in Porto de Galinhas. A one-year malacological survey was conducted to identify biological, abiotic, and environmental factors related to the host snail breeding sites. Data analysis used Excel 2010, GTM Pro, and ArcGis 10. A total of 11,012 B. glabrata snails were captured in 36 breeding sites, and 11 schistosomiasis transmission foci were identified. A negative correlation was found between breeding site temperature and snail density and infection rate, and a positive correlation with pH and salinity. The rainy season showed a positive correlation with snail density and infection rate. The study emphasizes the factors involved in the maintenance of schistosomiasis breeding sites, in light of persistence of this disease in Porto de Galinhas for more than 10 years.


Sign in / Sign up

Export Citation Format

Share Document