85 research outputs found
Reproductive biology of the pampas deer (Ozotoceros bezoarticus): a review
The pampas deer (Ozotoceros bezoarticus) is a South American grazing deer which is in extreme danger of extinction. Very little is known about the biology of the pampas deer. Moreover, most information has not been published in peer-reviewed scientific journals, and is only available in local publications, theses, etc. Therefore, our aim was to update and summarize the available information regarding the reproductive biology of the pampas deer. Moreover, in most sections, we have also included new, unpublished information. Detailed descriptions are provided of the anatomy of both the female and the male reproductive tract, puberty onset, the oestrous cycle and gestational length. Birthing and the early postpartum period are described, as are maternal behaviour and early fawn development, seasonal distribution of births, seasonal changes in male reproduction and antler cycle, reproductive behaviour, semen collection, and cryopreservation. Finally, an overview is given and future directions of research are proposed
Habitat use at fine spatial scale: how does patch clustering criteria explain the use of meadows by red deer ?
Large mammalian herbivores are keystone species
in different ecosystems. To mediate the effects of large
mammalian herbivores on ecosystems, it is crucial to understand
their habitat selection pattern. At finer scales, herbivore
patch selection depends strongly on plant community
traits and therefore its understanding is constrained by patch
definition criteria. Our aim was to assess which criteria for
patch definition best explained use of meadows by wild,
free-ranging, red deer (Cervus elaphus) in a study area in
Northeast Portugal. We used two clustering criteria types
based on floristic composition and gross forage classes, respectively.
For the floristic criteria, phytosociological approach
was used to classify plant communities, and its
objectivity evaluated with a mathematical clustering of the
floristic relevés. Cover of dominant plant species was tested
as a proxy for the phytosociological method. For the gross
forage classes, the graminoids/forbs ratio and the percentage
cover of legumes were used. For assessing deer relative use of
meadows we used faecal accumulation rates. Patches clustered
according to floristic classification better explained selection of patches by deer. Plant community classifications based on
phytosociology, or proxies of this, used for characterizing
meadow patches resulted useful to understand herbivore selection
pattern at fine scales and thus potentially suitable to
assist wildlife management decisions
Bioenergetics Failure and Oxidative Stress in Brain Stem Mediates Cardiovascular Collapse Associated with Fatal Methamphetamine Intoxication
Background: Whereas sudden death, most often associated with cardiovascular collapse, occurs in abusers of the psychostimulant methamphetamine (METH), the underlying mechanism is much less understood. The demonstration that successful resuscitation of an arrested heart depends on maintained functionality of the rostral ventrolateral medulla (RVLM), which is responsible for the maintenance of stable blood pressure, suggests that failure of brain stem cardiovascular regulation, rather than the heart, holds the key to cardiovascular collapse. We tested the hypothesis that cessation of brain stem cardiovascular regulation because of a loss of functionality in RVLM mediated by bioenergetics failure and oxidative stress underlies the cardiovascular collapse elicited by lethal doses of METH. Methodology/Principal Findings: Survival rate, cardiovascular responses and biochemical or morphological changes in RVLM induced by intravenous administration of METH in Sprague-Dawley rats were investigated. High doses of METH induced significant mortality within 20 min that paralleled concomitant the collapse of arterial pressure or heart rate and loss of functionality in RVLM. There were concurrent increases in the concentration of METH in serum and ventrolateral medulla, along with tissue anoxia, cessation of microvascular perfusion and necrotic cell death in RVLM. Furthermore, mitochondrial respiratory chain enzyme activity or electron transport capacity and ATP production in RVLM were reduced, and mitochondria-derived superoxide anion level was augmented. All those detrimental physiological and biochemica
Successful breeding predicts divorce in plovers
When individuals breed more than once, parents are faced with the choice of whether to re-mate with their old partner or divorce and select a new mate. Evolutionary theory predicts that, following successful reproduction with a given partner, that partner should be retained for future reproduction. However, recent work in a polygamous bird, has instead indicated that successful parents divorced more often than failed breeders (Halimubieke et al. in Ecol Evol 9:10734–10745, 2019), because one parent can benefit by mating with a new partner and reproducing shortly after divorce. Here we investigate whether successful breeding predicts divorce using data from 14 well-monitored populations of plovers (Charadrius spp.). We show that successful nesting leads to divorce, whereas nest failure leads to retention of the mate for follow-up breeding. Plovers that divorced their partners and simultaneously deserted their broods produced more offspring within a season than parents that retained their mate. Our work provides a counterpoint to theoretical expectations that divorce is triggered by low reproductive success, and supports adaptive explanations of divorce as a strategy to improve individual reproductive success. In addition, we show that temperature may modulate these costs and benefits, and contribute to dynamic variation in patterns of divorce across plover breeding systems
Predation services: quantifying societal effects of predators and their prey
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/167774/1/fee2336.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/167774/2/fee2336-sup-0001-PanelS1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/167774/3/fee2336-sup-0002-TableS1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/167774/4/fee2336_am.pd
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