Nocturnal Inshore Movement of the Mimic Shiner (Notropis volucellus): a Possible Predator Avoidance Behavior

1983 ◽  
Vol 40 (7) ◽  
pp. 888-894 ◽  
Author(s):  
David A. Hanych ◽  
Michael R. Ross ◽  
Robert E. Magnien ◽  
Amy L. Suggars

Diel seining documented a significant summer nocturnal inshore movement of the mimic shiner (Notropis volucellus) in Lake Itasca, Minnesota. This species initiated inshore movement at sunset, occupied the nearshore area throughout the night, and moved offshore by sunrise. Mimic shiners were collected in less than 1 m of water throughout inshore areas with sparsely developed macroscopic vegetation. Greatest relative abundance was observed at sites possessing the greatest expanse of sparsely or nonvegetated substrate. Relative abundance at inshore sites may be related to habitat characteristics of the sites or to the proximity of feeding habitat. These diel movements differed markedly from those exhibited by the mimic shiner in other lakes. The inshore movement in Lake Itasca may function to reduce crepuscular and nocturnal predation pressure. Our data support the hypothesis that freshwater fishes may possess behavioral plasticity sufficient to alter movement and distribution patterns according to prevailing conditions and that predation pressure may be important in altering prey behavioral patterns.

2021 ◽  
Vol 28 (6) ◽  
pp. 348-354
Author(s):  
Min Seock Do ◽  
Ki-Baek Nam

Studies on the distribution of species are important to understanding the interspecific ecological niche and habitat selection through geographic environmental information. Particularly, vipers in the same genus have been an important topic because they show differences in the preferred geographical environment, depending on the distance of the phylogenetic relationship. This study investigated the geographical environment of red-tongued pit vipers (Gloydius ussuriensis) and Central Asian pit vipers (Gloydius intermedius) in the mountainous area, Cheonmasan Mountain County Park, South Korea, from April 2012 to October 2014, to understand the relationships among their habitat characteristics and ecological niche. Red-tongued pit vipers mainly lived in low altitude, wet valley areas with a low solar reflectance, while Central Asian pit vipers inhabited high altitude, dry land with large amounts of sunshine. As a result, our study supports that the ecological niche of red-tongued pit vipers and Central Asian pit vipers, inhibiting in Cheonmasan Mountain was overlapped low according to the majority of geographical environmental variables. The differentiated diet preference might be took into consideration as one of the potential key factors to the ecological niche differentiation among two species.


Author(s):  
Fabio Stoch ◽  
Barbara Fiasca ◽  
Tiziana Di Lorenzo ◽  
Silvano Porfirio ◽  
Marco Petitta ◽  
...  

<p>In groundwater-fed springs, habitat characteristics are primarily determined by a complex combination of geomorphic features and physico-chemical parameters, while species assemblages are even more intricate. Springs host species either inhabiting the spring mouth, or colonizing spring habitats from the surface or from the aquifers which feed the springs. Groundwater species living in springs have been claimed as good candidates for identifying dual aquifer flowpaths or changes in groundwater pathways before reaching the spring outlets. However, the reliability of spring species as hydrological biotracers has not been widely investigated so far. Our study was aimed at analysing a large karstic spring system at three nested spatial scales in order: i) to assess, at whole spring system scale, the presence of a groundwater divide separating two aquifers feeding two spring units within a single spring system, by combining isotope analyses, physico-chemistry, and copepod distribution patterns; ii) to test, at vertical spring system scale, the effectiveness of copepods in discriminating surface and subsurface habitat patches within the complex mosaic spring environment; iii) to explore, at local spring unit level, the relative role of hydrochemistry and sediment texture as describers of copepod distribution among microhabitats. The results obtained demonstrated the presence of a hierarchical spatial structure, interestingly reflected in significant differences in assemblage compositions. Copepod assemblages differed between the two contiguous spring units, which were clearly characterized by their hydrochemistry and by significant differences in the groundwater flowpaths and recharge areas, as derived by the isotope analyses. The biological results suggested that stygobiotic species seem to be related to the origin of groundwater, suggesting their potential role as hydrological biotracers. At vertical scale, assemblage composition in surface and subsurface habitats was significantly different, both between spring units and among microhabitats, supporting strong habitat preferences of copepod species. At the smaller local scale, the response to habitat patchiness of subsurface copepod assemblages resulted in distribution patterns primarily defined by sediment texture, while the sensitivity to differences in hydrochemistry was negligible.</p>


The Auk ◽  
2006 ◽  
Vol 123 (4) ◽  
pp. 1069-1076 ◽  
Author(s):  
David A. Cimprich ◽  
Frank R. Moore

Abstract During migration, birds may store large quantities of fat to fuel long-distance flight. Because mass affects flight performance, fat migrants should behave with greater caution toward aerial predators than lean migrants. We tested a prediction of this hypothesis, namely, that fat birds will remain motionless longer than lean birds after a simulated encounter with a raptor. We captured Gray Catbirds (Dumetella carolinensis) during fall migration, classified their subcutaneous fat, exposed them to a model hawk, and then recorded the time until their first perch change. To determine whether the birds treated the simulated predator as a threat, we also tested them with a hexagon-shaped model and with no model. The birds remained motionless longer with the hawk model than either of the two other treatments. Fat birds remained motionless longer than lean birds when exposed to the hawk model, but we detected no difference with the other two treatments. These results provide evidence that fat affects the predator-avoidance behavior of Gray Catbirds during migratory stopover. That a difference between fat and lean groups was only apparent with the hawk model treatment suggests that the result is attributable to differences in the flight performance of the two groups rather than simply a difference in motivation to begin foraging. We suggest that fat should influence the behavior of a wide variety of migrant birds, particularly those species that typically carry greater fat reserves or that forage in more exposed situations than the Gray Catbirds we tested. La Grasa Afecta el Comportamiento de Evasión de Depredadores en Dumetella carolinensis durante las Paradas Migratorias


2018 ◽  
Vol 45 (2) ◽  
pp. 194
Author(s):  
K. A. Yao ◽  
E. A. Bitty ◽  
K. B. Kassé ◽  
Y. C. Kouakou ◽  
K. H. Yaokokoré-Beibro ◽  
...  

Context Duikers play a vital role in maintaining forest ecosystems, as both seed dispersers and prey. In West Africa, duikers are also an important source of food and income; however, it is likely that some species are now being hunted at unsustainable levels. So as to contribute to duiker conservation, we used line-transect data and additional information on dung and track counts to estimate relative abundance and establish distribution patterns of forest duikers in Côte d'Ivoire's Dassioko Sud Forest Reserve (DSFR), a poorly known, remnant coastal rainforest. We also collected basic information on hunting pressure. Methods Forest duiker counts were made twice per month from July 2013 to March 2014 on six line transects of varying lengths (5.6–6.7km) and in different regions of the DSFR, representing different habitat types. The number of sightings per kilometre walked, defined as ‘encounter rate', was used to compute an index of relative abundance. We recorded all evidence of poachers and used these data to generate a poaching index (# poaching signs per kilometre) for different habitat types. Key results The DSFR has lost three of seven total forest duiker species and populations of the four remaining species are declining. Encounter rates were greatest for Philantomba maxwellii (0.46 indices km–1) and accounted for 68% of total encounters. Cephalophus niger, C. dorsalis and C. silvicultor were encountered at similar (0.07 indices km–1) but much lower rates. For all species, mean encounter rates were highest in degraded forest (0.38–0.73 indices km–1), followed by secondary (0.2–0.44 indices km–1) and primary (0.19–0.44 indices km–1) forest. Conclusions Of the four forest duiker species still present in the DSFR, the black, bay and yellow-backed duikers are the most affected by anthropogenic pressures. Duiker abundance in the DSFR varies with habitat type. This variation is apparently influenced by differences in forest structure, poaching pressure and proximity to villages. Implications The study provides baseline data for future managing of ungulate populations in the DSFR. We recommend that a biomonitoring study of duiker populations be initiated immediately to help determine population trends, investigate habitat preferences, and help curb illegal hunting activities in this important forest reserve.


2014 ◽  
Vol 78 (7) ◽  
pp. 1272-1281 ◽  
Author(s):  
Rebecca Perkins ◽  
Clint Boal ◽  
Dale Rollins ◽  
Robert M. Perez

2008 ◽  
Vol 29 (2) ◽  
pp. 278-283 ◽  
Author(s):  
Mark Jordan ◽  
Howard Snell ◽  
Jennifer Hollis ◽  
Paul Stone

Abstract Gradients in habitat structure are expected to influence the outcome of selection on traits that contribute to communicative display. Galápagos lava lizards (Microlophus albemarlensis complex) on Isla Plaza Sur in the Galápagos Islands occur across a gradient of vegetative cover. Previous work in this population has shown that traits associated with predator avoidance are magnified in habitats with low vegetative cover. This pattern suggests that predation pressure differs by habitat and thus, may act to select against the elaboration of ornamentation. We measured the size of the chin patch, an ornament known to be used in intraspecific signaling, to test this hypothesis. The area of the chin patch was dependent on both snout-vent length and residual body mass. In contrast to expectation, males had larger chin patches in the sparsely vegetated habitat suggested to have high predation risk. This result raises questions about the presumed survival cost of ornament elaboration.


Sign in / Sign up

Export Citation Format

Share Document