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101.
Eduardo Soto-Galera Joel Paulo-Maya Eugenia López-López José Angel Serna-Hernández John Lyons 《Environmental management》1999,24(1):133-140
Chirostoma charari and C. compressum, and they are presumed extinct. Twelve (63%) of the remaining species had declines in distribution. Sixteen (80%) of the 20
localities sampled had lost species. The greatest declines occurred in Lago de Cuitzeo proper and in the lower portion of
the Río Grande de Morelia watershed. Species losses from the lake were attributable to drying and hypereutrophication of the
lake because of substantial reductions in the amount and quality of tributary inputs, whereas losses from the Río Grande de
Morelia watershed were the result of pollution from agricultural, municipal, and industrial sources, especially in the region
around the city of Morelia. Three localities in the upper portion of the Río Grande de Morelia watershed—Cointzio reservoir,
La Mintzita spring, and Insurgente Morelos stream—contained most of the remaining fish species diversity in the basin and
deserve additional protection. Fish faunal changes indicated major declines in the health of aquatic ecosystems in the Morelia–Cuitzeo
basin. 相似文献
102.
Effects of paternal care on reproductive success in the polygynous spotless starling Sturnus unicolor 总被引:2,自引:0,他引:2
J. Moreno José P. Veiga Pedro J. Cordero Eduardo Mínguez 《Behavioral ecology and sociobiology》1999,47(1-2):47-53
For males of socially polygynous avian species like the spotless starling, there may exist a trade-off between investing in
paternal care and controlling several nests. To determine how the intensity of paternal care affects reproductive success
per brood sired or expressed as the total number of young raised in all nests controlled by the same male, it is necessary
to manipulate paternal care. Testosterone (T) has been shown to depress the tendency for males to care for their young, and
induces them to acquire more mates. The effects of paternal care on reproductive success were studied by treating certain
male starlings with exogenous T and others with the antiandrogen cyproterone acetate (CA), and comparing the parental behavior
of T- and CA-males throughout the breeding season with that of controls. CA-males fed their chicks more during the first week
after hatching than T-males, with controls feeding at intermediate rates, both on a per nest basis and as total effort for
all nests controlled by the same male. Paternal feeding rates during the first week of chick life had a significant positive
effect on the number of fledged young. The hormone treatment significantly affected the number of chicks raised per nest,
CA-males having a higher breeding success per nest than T-males, and controls showing intermediate levels of success. There
was no significant effect of treatment on total reproductive success attained by males throughout the season. In the polygonous
spotless starling, the intensity of paternal care of young affects reproductive success per nest positively but not on a seasonal
basis.
Received: 6 February 1999 / Received in revised form: 30 June 1999 / Accepted: 11 July 1999 相似文献
103.
Axel Hochkirch Michael J. Samways Justin Gerlach Monika Böhm Paul Williams Pedro Cardoso Neil Cumberlidge P. J. Stephenson Mary B. Seddon Viola Clausnitzer Paulo A. V. Borges Gregory M. Mueller Paul Pearce-Kelly Domitilla C. Raimondo Anja Danielczak Klaas-Douwe B. Dijkstra 《Conservation biology》2021,35(2):502-509
Measuring progress toward international biodiversity targets requires robust information on the conservation status of species, which the International Union for Conservation of Nature (IUCN) Red List of Threatened Species provides. However, data and capacity are lacking for most hyperdiverse groups, such as invertebrates, plants, and fungi, particularly in megadiverse or high-endemism regions. Conservation policies and biodiversity strategies aimed at halting biodiversity loss by 2020 need to be adapted to tackle these information shortfalls after 2020. We devised an 8-point strategy to close existing data gaps by reviving explorative field research on the distribution, abundance, and ecology of species; linking taxonomic research more closely with conservation; improving global biodiversity databases by making the submission of spatially explicit data mandatory for scientific publications; developing a global spatial database on threats to biodiversity to facilitate IUCN Red List assessments; automating preassessments by integrating distribution data and spatial threat data; building capacity in taxonomy, ecology, and biodiversity monitoring in countries with high species richness or endemism; creating species monitoring programs for lesser-known taxa; and developing sufficient funding mechanisms to reduce reliance on voluntary efforts. Implementing these strategies in the post-2020 biodiversity framework will help to overcome the lack of capacity and data regarding the conservation status of biodiversity. This will require a collaborative effort among scientists, policy makers, and conservation practitioners. 相似文献
104.
105.
Joana?MadureiraEmail author Inês?Paciência Jo?o?Rufo André?Moreira Eduardo?de?Oliveira Fernandes Alcides?Pereira 《Environmental geochemistry and health》2016,38(2):523-533
Radon is a radioactive gas, abundant in granitic areas, such as in the city of Porto at the north-east of Portugal. This gas is a recognized carcinogenic agent, being appointed by the World Health Organization as the leading cause of lung cancer after smoking. The aim of this preliminary survey was to determine indoor radon concentrations in public primary schools, to analyse the main factors influencing their indoor concentration levels and to estimate the effective dose in students and teachers in primary schools. Radon concentrations were measured in 45 classrooms from 13 public primary schools located in Porto, using CR-39 passive radon detectors for about 2-month period. In all schools, radon concentrations ranged from 56 to 889 Bq/m3 (mean = 197 Bq/m3). The results showed that the limit of 100 Bq/m3 established by WHO IAQ guidelines was exceeded in 92 % of the measurements, as well as 8 % of the measurements exceeded the limit of 400 Bq/m3 established by the national legislation. Moreover, the mean annual effective dose was calculated as 1.25 mSv/y (ranging between 0.58 and 3.07 mSv/y), which is below the action level (3–10 mSv). The considerable variability of radon concentration observed between and within floors indicates a need to monitor concentrations in several rooms for each floor. A single radon detector for each room can be used, provided that the measurement error is considerably lower than variability of radon concentration between rooms. The results of the present survey will provide useful baseline data for adopting safety measures and dealing effectively with radiation emergencies. In particular, radon remediation techniques should be used in buildings located in the highest radon risk areas of Portugal. The results obtained in the current study concerning radon levels and their variations will be useful to optimize the design of future research surveys. 相似文献
106.
107.
108.
Christian Luis Rodriguez-Enriquez Eduardo Tadeo Juan Rull 《Behavioral ecology and sociobiology》2013,67(6):937-946
Postcopulatory processes can influence male reproductive success in several animal species. Females can use different mechanisms to bias male paternity after copulation. One of such mechanisms consists in expelling all or part of the ejaculate after copulation. Euxesta bilimeki is an Ulidiid fly whose females not only frequently expel ejaculates after mating but also consume the ejaculate after expulsion. In order to understand the significance of these behaviors we examined video recordings of courtship, copulatory, and postcopulatory behaviours. The presence of sperm in female storage organs was confirmed after mating with males of different sizes and was correlated with duration of courtship, copulation, and the period from the end of copulation to ejaculate expulsion. The effect of ejaculate consumption on female fitness (fecundity and longevity) was compared among females held under different dietary treatments: a rich diet consisting of protein, sugar and water, an intermediate diet composed of sugar and water, a poor diet of only water and females that were completely deprived of food and water. All of the observed females expelled ejaculates after mating. The probability of storing sperm in the two spermathecae and the ventral receptacle was correlated with interactions between the duration of all behaviours examined and male size. Except for starved females, who lived longer when allowed to consume ejaculates, ejaculate consumption had no effect on fitness. Results suggest that females can bias sperm storage according to male mating effort, while the consumed ejaculate had some nutritional value only evident when females were completely starved. 相似文献
109.
Maren?HuckEmail author Eduardo?Fernandez-Duque 《Behavioral ecology and sociobiology》2012,66(3):505-517
According to the Evolutionary Theory of the Family, the replacement of one pair-member by an intruder may have profound consequences
for the existing offspring. Step-parents are expected to provide less care towards unrelated immatures than to genetic offspring,
unless caring also serves as a mating strategy. Furthermore, because an intruder will be a potential mate for opposite-sexed
offspring, relationships between offspring and same-sex parents are predicted to deteriorate. To test these predictions, we
studied an Azara’s owl monkey (Aotus azarai) population in Argentina exhibiting serial monogamy and bi-parental care. Since 1997, we have collected demographic data
from ca. 25 groups and inter-individual distance data from ca. 150 marked individuals. First, we compared survival and dispersal
age of immatures in groups with and without replacements to investigate whether parental care serves as a mating strategy.
Second, we compared sex-specific age at dispersal for groups with replacement of opposite-sex parents, same-sex parents, or
in stable groups in order to test whether relationships between offspring and same-sex parents deteriorated after the replacement
of the other parent. Survival and dispersal ages were not negatively associated with replacements, suggesting that male care
might serve, at least partly, as a mating strategy. The time lag between a replacement and the subsequent dispersal of female
offspring was greater if the intruder was a male, while the offspring and same-sex parents were less often nearest neighbors
after replacements than before. Our results suggest that family disruption through the replacement of a parent is not associated
with decreased offspring survival or early dispersion of juveniles, but deteriorates parent–offspring relationships. 相似文献
110.
Concei??o Juana Fortes óscar Ferreira Paulo A. Silva Theo Moura Rui Capit?o Luís Amante Michalis Vousdoukas Maria Bezerra 《Journal of Coastal Conservation》2012,16(4):461-472
In the framework of a research project entitled ??BRISA??BReaking waves and Induced SAnd transport??, a methodology was devised to characterize the waves joining together in-situ measurements and numerical wave propagation models. With this goal in mind, a number of in-situ measurements were made, for selected positions in front of Praia de Faro (South Portugal), during four days (25th to 28th March, 2009) by using different types of equipments (e.g., resistive wave gauges, pressure sensors, currentmeters and a new prototype pore pressure sensor using optical fibre). Wave records were obtained simultaneously offshore (at a water depth of 11.7?m below mean sea level, MSL) and at the surf and swash zones. The data processing and analysis were made by applying classical time domain techniques. Numerical simulations of the wave propagation between offshore and inshore for the measurement period were performed with two numerical models, a 1D model based on linear theory and a nonlinear Boussinesq-type model, COULWAVE, both forced by the measured offshore wave conditions of 27th March 2009. Comparisons between numerical results and field data for the pressure sensors placed in the surf and swash zones were made and discussed. This approach enables to evaluate the performance of those models to simulate those specific conditions, but also to validate the models by gaining confidence on their use in other conditions. 相似文献