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1.
The influence of red deer (Cervus elaphus) grazing on grassland production for forage conservation at the forest border during the vegetation period was studied on
three locations (Mala gora, Cvišlerji, and Mačkovec) in the Kočevje region (SE Slovenia). The experiment lasted from the 25th
of March until the 8th of October 2002. Portable cages were used to exclude red deer from grazing the herbage. At four sampling
dates in the season, herbage air dry matter (DM) yield was measured at three different observations (cage-protected plot,
cage-protected plot only two to three weeks before sampling date, otherwise freely grazed (removed), and unprotected plot).
The results from the experiment showed that red deer grazed on grassland through the entire season and that the regeneration
capability of sward was the highest in summer, middle in spring and smallest in autumn. On unprotected plots, an average reduction
of 50% of herbage DM yield was found with the most damaged sites also up to 80% reduction. 相似文献
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《Mammalian Biology》2014,79(6):362-368
Rutting behaviour of red deer stags (Cervus elaphus) includes an extensive repertoire of visual and acoustic signals directed either to rival males or to females. As in other mammals, olfactory communication is expected to play a central role in these rutting interactions too, but this has rarely been investigated. Only during the rutting season, red deer males show a conspicuous black spot area throughout most of their underbelly produced by the impregnation of substances with a strong scent. Here, we examined the origin of these compounds and their potential role as chemical signals. By using gas chromatography–mass spectrometry (GC–MS), we identified 67 compounds in the hair from the belly black spot of red deer stags, mainly heterocyclic aromatic organic compounds, such as m-cresol, benzoic acid, cyclohexanecarboxylic acid and ethylphenol, but we also found steroids, such as cholesterol and androstane-3,17-dione, carboxylic acids and their esters between n-C6 and n-C22, alcohols, squalene and other minor compounds. Many of these compounds are found in the belly black spot but not in other hair areas, and may have originated from several sources, such as the urine or the sebaceous glands of the skin, which impregnated the belly. Moreover, we found differences in chemical profiles depending on age, with older males having higher proportions of benzoic acid and androstane-3,17-dione, but lower proportions of m-cresol. Because most of these compounds are strongly odoriferous, and appear related to male characteristics, our data indicate that scent from the hairs forming the black spot of the belly may be regarded as an overlooked new sexual chemical signal in red deer in the context of competition for mates during the rutting season. 相似文献
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《Palaeoworld》2023,32(3):547-554
Mesotheres (Notoungulata: Typotheria) are among the most common mammals found in upper Miocene to Pliocene deposits of central Argentina, including the classic type Monte Hermoso locality, which defines the Montehermosan South American Land Mammal “Age”. Nevertheless, the correct name for the mesothere species from this site has been shrouded in uncertainty for well over a century due to questions of taxonomic priority, specimen provenance, and ontogenetic changes in dental formula. Since the mesotheres from Monte Hermoso were named, three distinct species have been formally considered as the type species of the genus: (1) Pseudotypotherium bravardi; (2) “Pseudotypotherium” maendrum; and (3) Pseudotypotherium exiguum. However, none of these species is a nominal species of the Pseudotypotherium genus; all three were originally referred to Typotherium. Article 67.2 of the International Code of Zoological Nomenclature (ICZN, 1999) indicates that only species considered as nominal species are eligible to set the type; in the case of Pseudotypotherium, these include: P. pulchrum, P. carlesi, P. hystatum, and P. carhuense. We conclude that Pseudotypotherium pulchrum F. Ameghino, 1904 (holotype MACN A 10299, Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”, Ameghino Collection), is the type species of the mesotheriid notoungulate genus from Monte Hermoso. According to Article 68.2, F. Ameghino fixed the type by original designation in 1904 when he described P. pulchrum and included “n. g., n. sp.”. Two of the other species previously considered species P. (= T.) bravardi and P. (= T.) exiguum are invalid as type species according to Article 70.2, since their designations overlooked the previous type fixation. The third species (M. (= T.) maendrum) represents a different mesothere genus (Mesotherium) that only occurs in younger (Pleistocene) deposits. Our analysis puts an end to a historical debate that has been ongoing for more than a century regarding the identity of this well-represented late Miocene–Pliocene mesotheriine genus (Pseudotypotherium). This study provides a solid taxonomic foundation for future studies on intraspecific and ontogenetic variation of Pseudotypotherium pulchrum. 相似文献
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Shane?K.?MaloneyEmail author Graeme?Moss Duncan?Mitchell 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2005,191(11):1065-1077
We recorded the body axis orientation of free-living black wildebeest relative to incident solar radiation and wind. Observations
were made on three consecutive days, on six occasions over the course of 1 year, in a treeless, predominantly cloudless habitat.
Frequency of orientation parallel to incident solar radiation increased, and perpendicular to incident solar radiation decreased,
as ambient dry-bulb temperature or solar radiation intensity increased, or wind speed decreased. We believe these changes
were mediated via their effect on skin temperature. Parallel orientation behavior was more prominent when the wildebeest were
standing without feeding than it was when they were feeding. We calculate that a black wildebeest adopting parallel orientation
throughout the diurnal period would absorb 30% less radiant heat than the same animal adopting perpendicular orientation.
Parallel orientation was reduced at times when water was freely available, possibly reflecting a shift from behavioral to
autonomic thermoregulatory mechanisms. The use of orientation behavior by black wildebeest is well developed and forms part
of the suite of adaptations that help them to maintain heat balance while living in a shadeless, often hot, environment. 相似文献
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Impacts of ungulates on the demography and diversity of small mammals in central Kenya 总被引:3,自引:3,他引:0
Felicia Keesing 《Oecologia》1998,116(3):381-389
The impacts of ungulates on small mammals in an East African savanna habitat were investigated by monitoring the population
and community responses of small mammals on replicated 4-ha plots from which ungulates had been excluded. The dominant small
mammal in this habitat is the pouched mouse, Saccostomusmearnsi, a medium-sized murid rodent. Eight other small mammal species, including Arvicanthis sp., Mus sp., Mastomys sp., Dendromus sp., Crocidura sp., and, rarely, Tatera sp., Aethomys sp., and Acomys sp., were also captured. The dominant ungulates are elephant (Loxodonta africana), giraffe (Giraffa camelopardalis), Grevy's and common zebra (Equus grevyi and E. burchelli), buffalo (Syncerus cafer), eland (Taurotragus oryx), Grant's gazelle (Gazella granti), and domestic cattle. Within 1 year, S. mearnsi populations had responded dramatically to the exclusion of large mammals by a two-fold increase in density, a difference
that was maintained through pronounced seasonal fluctuations in the second year. Though individual pouched mice showed no
significant differences in their use of space with and without ungulates, male S. mearnsi maintained significantly higher body weights in the absence of ungulates, indicating that habitat quality had increased.
One other species, Mastomys sp., also increased in the absence of ungulates. Overall, the small mammal community maintained relatively constant species
diversity on the plots to which ungulates did not have access. On the plots to which ungulates did have access, on the other
hand, there was a rapid 75% decrease in diversity in the control plots during one trapping session. Ungulates are most likely
affecting small mammals through their effects on food quality, since there were no detectable differences in their exposure
to predators, as determined by vegetative cover, in the absence of ungulates. These results demonstrate that ungulates can
have strong and rapid impacts on small mammal abundance and diversity in East African savannas, an interaction which has not
previously been given serious consideration.
Received: 28 December 1997 / Accepted: 11 May 1998 相似文献
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Resource partitioning between sympatric wild and domestic herbivores in the Tarangire region of Tanzania 总被引:6,自引:1,他引:5
The effect of the introduction of an exotic species (cattle) into a native African herbivore assemblage was investigated
by studying resource partitioning between zebu cattle, wildebeest and zebra. Resource partitioning was investigated by analysing
grass sward characteristics (such as sward height and percentage nitrogen in leaves) of feeding sites selected by the different
herbivore species. Linear discriminant analysis was used to determine whether a distinction could be made between feeding
sites selected by the different animal species or whether the animal species showed overlap in resource use by selecting similar
feeding sites. Wildebeest and zebra did not show overlap in resource use except in the wet season when resources were ample.
Cattle showed overlap in resource use with zebra in the early wet season and with wildebeest in the early dry season, seasons
when food limitation is likely. In the wet season, cattle showed overlap in resource use with both zebra and wildebeest.
Implications of these results for competitive relationships between livestock and wildlife are discussed. We suggest that
interpretation of overlap in resource use may be different for an assemblage of long-term coexisting native species as compared
to an assemblage of native and exotic species. Among native herbivores, overlap in resource use is not expected based on evolutionary
segregation. In a native assemblage to which an exotic species has been introduced, however, overlap in resource use can occur
under food-limited conditions and consequently implies competition.
Received: 1 September 1998 / Accepted: 20 April 1999 相似文献
9.
Questions: What is the potential of sheep to serve as seed dispersers via ingestion and defecation in calcareous grasslands? Is the presence of viable seeds from dung correlated with specific seed traits? Location: Calcareous grasslands, South Limburg, the Netherlands/Belgium. Methods: Dung samples (n=24) from sheep were collected between September 2006 and November 2007 from five sites with Mesobromion plant communities, and communities of Nardo‐Galion saxatilis. Germinability and identity of seeds in the dung samples were ascertained from germination of seedlings under glasshouse conditions. Seed traits of species with viable seeds in dung were compared with those present in the local species pool. Results: Seventy‐two plant species from 23 plant families had viable seeds in sheep dung. The plant families encountered most frequently were Gramineae and Compositae. The most abundant and frequently recorded plant species in dung samples was Urtica dioica, accounting for >80% of the total number of seeds. Mean seed density in sheep dung was 0.8 seeds g?1 dry matter. Seeds with low seed mass and a high seed longevity index were over‐represented in dung. Viable seeds >2.5 mg were infrequent in the dung samples. Conclusions: We conclude that sheep are potentially important dispersers of plant species in Dutch calcareous grasslands. Although smaller seeds were relatively abundant in sheep dung, it cannot be excluded that this was mainly caused by differences in seed abundance. 相似文献
10.
Vegetative and chemical responses to simulated leaf browsing during the growth season, and their subsequent effect on herbivory,
were studied on Combretum apiculatum Sonder (Combretaceae) in Botswana. Treatments (50% and 100% leaf and shoot apex removal) were performed just before the shoot
growth curve levelled out, and responses recorded 3 months later, just before leaf fall. Compared to controls, defoliation
treatments, removing apical dominance, reduced growth in tree height and increased shoot mortality, although the production
of lateral shoots increased. At the end of the trial, there was no difference in total length of annual shoots between treatment
groups. Significant refoliation occurred only after 100% defoliation. Refoliated leaves were smaller and the 100% defoliated
trees had a lower final leaf biomass. Total leaf biomass production was, however, equal for all treatment groups. Refoliated
leaves contained higher levels of N, lower levels of acid-detergent fibre (ADF) and total phenolics, and showed a trend towards
lower levels of condensed tannins, compared to leaves on control trees. Such chemical changes may be due to either carbon
stress or to younger physiological age of new leaves. In spite of the observed potential increase in food quality, we found
no evidence of increased levels of insect or ungulate herbivory on refoliated leaves, which, at least for insect herbivory,
may be explained by the reduction in temporal availability of leaves. We conclude that the single severe defoliation was not
detrimental to C. apiculatum in the short-term, although the resource loss and induced compensatory growth may produce negative effects during subsequent
growth seasons. 相似文献