Ecological strategies of a small hibernator, the western jumping mouse Zapus princeps

1983 ◽  
Vol 61 (1) ◽  
pp. 232-240 ◽  
Author(s):  
Jack A. Cranford

The seasonal emergence, reproduction, diet, fat deposition, and immergence of six wild populations of Zapus princeps from elevations of 1860–2900 m were studied by trap–recapture methods and laboratory observations from April 1974 to November 1978. Emergence timing varied widely between and within sites in different years. It was not related to increasing elevation but to site quality. Vegetative growth was an excellent predictor of emergence timing at all sites. Emergence of males and females was synchronous except above 2200 m where males preceded females by 3–9 days. Field and laboratory experiments and observations were made on Z. princeps, including habitat preferences, competitive relationships, population density (maximum = 32.4/ha), length and timing of the active cycle (87 days), reproductive activity (1 litter/year), litter size [Formula: see text], age structure of populations, growth rates, seasonal fat deposition (0.65 g/day),and home-range size(0.17–0.61 ha). This attempts to formulate a coherent picture of the system of strategies by which a small hibernator adapts to its environment.

2002 ◽  
Vol 23 (4) ◽  
pp. 495-504 ◽  
Author(s):  
Otavio Marques ◽  
Lígia Pizzatto

AbstractThe reproductive biology of the false coral snake, Oxyrhopus guibei, was studied through dissection of 496 specimens, combined with observations on captive individuals. Males mature with smaller body size than females, females attain much larger body size, and male-male combat is not expected. Clutch size ranged from 3 to 20, and was correlated with female length. Reproductive cycles in both males and females seem to be continuous, with vitellogenesis and spermatogenesis occurring throughout the year. Reproductive activity in both sexes decreased at the end of the rainy season possibly due to previous intense reproductive activity in more favorable climatic conditions. The smaller number of individuals collected at the end of the rainy season apparently occurs due to the decrease of reproductive activity of this snake.


1992 ◽  
Vol 13 (2) ◽  
pp. 121-133 ◽  
Author(s):  
Fabio M. Guarino ◽  
Vincenzo Caputo ◽  
Francesco Angelini

AbstractThis paper describes the reproductive cycle in male and female newts Triturus italicus (Peracca, 1898) from a mountain population living in southern Italy. The male shows a well-defined seasonal testicular cycle: spermatogenesis almost stops from November to March, resuming in April-May; the maturative stage of spermatogenesis occurs in summer and spermiohistogenesis is completed by late October. Spermiation starts in late autumn and culminates in the next spring. The female shows a seasonal ovarian cycle. Vitellogenesis starts in September; ovulation and egg deposition occur between late January and early June. Thus potentially long reproductive activity is demonstrated in both males and females of T italicus. Testicular and ovarian weights seem to be reliable indices of the reproductive status of an animal. Annual variation in gonadal weight appears unrelated to annual variation in fat body weight in both sexes.


2015 ◽  
Vol 36 (1) ◽  
pp. 13-25 ◽  
Author(s):  
Albert Vilardell-Bartino ◽  
Albert Vilardell-Bartino ◽  
Xavier Capalleras ◽  
Albert Vilardell-Bartino ◽  
Xavier Capalleras ◽  
...  

To avoid the possible extinction of the last native population of western Hermann’s tortoise in the Iberian Peninsula it is essential to make sound management decisions. Knowledge of macro and microhabitat use and home range size has considerable practical value for land managers. With this aim we first studied the home range and habitat preferences in western Hermann’s tortoises by radio tracking 15 adults weekly from March 2008 to May 2009 in three localities within the Albera population range (NE Iberian Peninsula). We estimated home ranges with Fixed Kernel estimator (FK) and Minimum Convex Polygon (MCP) after checking tortoise site fidelity. We observed that home range size did not differ significantly between males and females (mean FK = 2.01 ha, mean MCP = 3.01 ha). Secondly, we studied macrohabitat selection using a vegetation map. Preferred habitats were open shrubland, open forest and barren land during the activity period, and dense forest, dense shrubland and open shrubland during the hibernation. Next, we assessed microhabitat selection along five periods of the annual cycle: hibernation, emergence from hibernation, spring, summer and autumn. We then located marked tortoises weekly and classified the plant species observed in each location. Principal component analyses showed that tortoises selected shrubs with trees during hibernation, bramble during summer and herbaceous habitat during the breeding season. All these results can provide guidelines for management programs that set aside areas of habitat critical to conserve viable populations, although it is also important to prevent mortality from forestry works. We therefore tested a new brush cutter head accessory to achieve tortoise-safe undergrowth clearing. To this aim we distributed 52 frozen hybrid tortoises among eight plots of 100 m2, cleared six of these plots with the accessory and two without it, and evaluated the scars of the blade on caparaces. We observed no damage in plots that were cleared with the accessory but scars in most carapaces in the plots cleared without it (with potential mortality ranging from 40% in neonates to 100% in adults). These results outline the importance of supporting habitat management decisions with proper field studies.


1982 ◽  
Vol 60 (11) ◽  
pp. 2641-2645 ◽  
Author(s):  
Michael Berrill ◽  
Michael Arsenault

In southern Ontario in the springs of 1980, 1981, and 1982 the crayfish Orconectes rusticus bred explosively when water temperatures rose above 4 °C. Copulations occurred frequently as sexually mature males and females wandered over the substrate at night. Males fought with each other and interrupted copulating pairs. In 1980 and 1981, females began to sequester themselves and extrude their eggs 11–12 days after copulations began. Males then gradually wandered and fought less, began feeding, and the breeding period ended approximately 4 weeks after the initiation of frequent copulations. In 1982, a delayed spring resulted in a far shorter breeding period. Laboratory experiments indicated that although a rise in water temperature initiated breeding events, including egg extrusion, the degree of necessary temperature increase may be inversely correlated with the duration of lengthening photoperiod to which females are exposed. Females which did not copulate in spring extruded eggs which were mostly infertile, emphasizing the importance of spring copulation in this northern orconectid.


2012 ◽  
Vol 62 (4) ◽  
pp. 381-396 ◽  
Author(s):  
Florencia Bonatto ◽  
Daniela Gomez ◽  
Andrea Steinmann ◽  
José Priotto

Patterns of space use and sexual dimorphism are frequently used to infer mating systems. We examined body size and home range size and intra- and intersexual overlap degree in order to elucidate mating strategy of Akodon azarae males. We studied spacing patterns using 113 and 129 home ranges established by males and females, respectively, in four 0.25 ha enclosures during the breeding season. Significant differences between sexes in home range size and overlap degree were found. Male home ranges were always larger than those of females. We observed exclusive space use among males and among females. Considering only those males that shared their home ranges with females, average intersexual overlap value was about 50%. Males mainly overlap their home ranges with home ranges of two or three females. Significant differences in body size were found between males and females, with males being larger. We concluded that space use and sexual dimorphism in this species is consistent with patterns characteristic of polygynous rodents, and we propose a polygynous system in A. azarae.


Agronomy ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2132
Author(s):  
Andraž Čarni ◽  
Mirjana Ćuk ◽  
Daniel Krstonošić ◽  
Željko Škvorc

Since grasslands provide many ecosystem services, there are often different opinions on their management (e.g., agronomy, ecology, botany). Multidisciplinary research on this topic is therefore needed. This article focuses on the impact of ecological conditions, functional groups, ecological strategies, floristic composition (through habitat preference of species), major floristic gradients (presented as first two NMDS axes), and the management of forage quality. We estimated the forage quality using indicator values. All of the available vegetation plots in the region on wet and mesic meadows, managed pastures, and tall-herb meadow/pasture fringes on deeper or shallower soils (i.e., grasslands) were collected, organized in a database, and elaborated according to standard procedure. We used a widely accepted grassland classification system that uses floristic composition to define grassland types. Based on an NMDS ordination diagram and according to functional groups, ecological strategies, and habitat preferences (behavior of species) and management, we defined three major groups: mesic meadows (mowed), wet meadows (mowed), and pastures (grazed). We correlated all groups’ functional groups, ecological strategies, habitat preferences (behavior of species), major floristic gradients, management, and forage quality. We found that forage quality mainly depends on moisture conditions and that nutrients and grazing are less important. Within the grasslands under consideration, mesic meadows and mesic pastures have the highest forage quality.


1971 ◽  
Vol 2 (2) ◽  
pp. 132-138 ◽  
Author(s):  
Hans Dreisig

AbstractThe activity of the cockroach Ectobius lapponicus was found to differ in males and females in the field, the males being active during the afternoon, the females after sunset. The difference was thought to be due to an inhibition by low temperatures in the males, displacing the activity towards an earlier period of the day. This is in accordance with a theory concerning sensitization, and different thresholds of release dependent on light and temperature as established for the stridulation in Orthoptera Ensifera and the locomotion in a domestic cockroach. A relationship between the amount of activity and the relative humidity was found in the nymphs. Laboratory experiments showed that the activity at constant temperature was released by a change from light to darkness. If low temperatures were applied during the dark period, the activity was displaced to the latter half of the light period. The influence of illumination on the activity was investigated, a faint illumination being more favourable than total darkness.


1992 ◽  
Vol 19 (2) ◽  
pp. 137 ◽  
Author(s):  
GW Arnold ◽  
DE Steven ◽  
A Grassia ◽  
J Weeldenburg

The home ranges were studied from 1977 to 1981 of western grey kangaroos (Macropus fuliginosus) living in a 300-ha remnant of wandoo [Eucalyptus wandoo] surrounded by farmland at Baker's Hill, Western Australia. The M. fuliginosus population varied from 140 to 200 animals during the study. In 1979, four females (>30 kg) and 2 adult males (31 kg and 47 kg) were fitted with radio-transmitters and their movements recorded. The home ranges of these animals varied from 39 to 70 ha; the average overlap in the area used during the day and that used at night was 16.4%. Many of the kangaroos fed on farmland at night. The night ranges of 51 marked kangaroos were recorded using a spotlight. The animals showed a strong fidelity to their home ranges. Only 3 males (about 5-yr-old) shifted their night ranges; the centres of the ranges moved only 600-800 m. Older males had significantly larger night ranges than younger males and females. Individual females and the younger males showed preferences for using particular access points to get onto farmland; the older males showed no preferences. The core areas of the night ranges of many adult females overlapped closely in 'groups', but there was no evidence of 'mob' home ranges that were socially separated.


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