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111.
112.
We used interdemic variation in the tendency to form mixed-species groups to examine the costs and benefits of association
among the primates of Kibale National Park, Uganda. A year-long survey of six sites revealed that the amount of time that
the five common diurnal primates [red colobus (Procolobus
tephrosceles), black-and-white colobus (Colobus
guereza), redtail monkeys (Cercopithecus
ascanius), blue monkeys (Cercopithecus
mitis), and grey-cheeked mangabeys (Lophocebus
albigena)] spent in mixed-species groups varied dramatically among sites. In many cases, the proportion of time that species associated
was positively related to their densities. By using detailed behavioral observations of redtail monkeys and red colobus made
over 4 years (2660 h) at four sites, we were able to reject the null hypothesis that associations occur by chance for only
one of four sites. However, a correlative approach exploring the costs and benefits of association suggests that ecological
variables do influence association patterns. We found that redtail monkeys and red colobus overlapped in diet (19.2% of their
foraging effort) and traveled further when in mixed-species groups than when alone. Having demonstrated this, we examined
the applicability of the ecological constraints model for predicting the proportion of the time spent in mixed-species groups
based on food availability. For this analysis we concentrated on red colobus from the site with 35 months of observation and
demonstrated that their tendency to be in mixed- species groups was related to food availability. We used two methods to examine
if mixed-species associations function to decrease predation risk. First, chimpanzees are known to prey heavily on red colobus,
but rarely kill other primates. The time red colobus spent in mixed-species groups was correlated to chimpanzee density, but
it was not for the other monkey species, suggesting that mixed-species groups serve to decrease predation risk. Second, when
red colobus groups contain more infants and are presumably at the greatest risk of predation, they form mixed-species groups
most often. These results demonstrate that the costs and benefits of mixed-species associations vary dramatically over small
spatial and temporal scales. If such variation is generally the case, then studies conducted at different locations or different
times could easily highlight the importance of difference selective agents in favoring mixed-species associations.
Received: 10 February 1999 / Received in revised form: 16 September 1999 / Accepted: 2 October 1999 相似文献
113.
仙居县城乡居民消费差异的生态足迹分析 总被引:20,自引:0,他引:20
根据生态足迹理论,以浙江省仙居县为例,利用统计调查和问卷调查资料,分别计算了城乡居民生活消费的生态系统占用情况。计算结果表明,该地城市居民的生活消费所占用的生态系统是农村居民所占用的1.73倍,差异最大的是草地,其次是水域、建筑用地、化石能源和耕地,对于林地的占用则是农村居民大于城市居民。 相似文献
114.
115.
Simin Fadaee 《Local Environment》2016,21(11):1305-1316
The existing scholarship on alternative institutional designs around environmental issues mostly focuses on ideals, goals and practices of these designs. It remains unclear under which circumstances these initiatives emerge and expand. Moreover, those scholars who address the emergence and expansion of these initiatives focus on examples which are located in advanced industrialised societies. It remains unclear why and how these alternative institutions emerge in non-industrialised societies and countries which have not gone through the same growth path as their advanced industrialised counterparts. Consequently, transformative implication of these initiatives for broader social change in non-advanced industrialised societies has not been explored. In this paper, I show that in Iran the emergence of these alternative designs should be understood within the context of post-contentious politics. I present original research on a cooperative that embraces an alternative lifestyle and whose aim is to create Iran's first ecovillage. This case study discusses one kind of response to the contraction of space for civil society and environmental non governmental organisations in Iran. The paper adds to our understanding of the interplay between democratisation processes and environmental activism. 相似文献
116.
Wang Jing''''ai - Mao Rui Yang Mingchuan & Zhou Junju College of Geography & Remote Sensing Key Laboratory of Regional Geography of Beijing Normal University Key Laboratory of Environmental Change Natural Disaster of Ministry of Education of China College of Resources Science & Technology Beijing Normal University Beijing China 《中国人口.资源与环境(英文版)》2005,3(2)
1 INTRODUCTIONWater shortage will be one of the common risks peoplehave to face in the 21st century. China, a country withwater shortage, possesses only as much as 1/4 of the world'smean occupation for every person and is enlisted as oneof the thirteen countries where water is in a great shortage.Furthermore, in China, the water resources distributionhas been terribly unbalanced from region to region. NorthChina, covering 15 provinces, possessing 45% of thefarmland and 38% of the populat… 相似文献
117.
K. E. Arnold 《Behavioral ecology and sociobiology》2000,48(5):385-391
Living with relatives can be beneficial to individuals via the evolution of kin-directed altruism, but this is tempered by
the increased risk of inbreeding. Therefore, in social species, the ability to recognise relatives can be highly advantageous.
This study focuses on kin discrimination in the Lake Eacham rainbowfish, Melanotaenia eachamensis, an endangered freshwater species from north-east Queensland, Australia. First, I examined kin recognition abilities when
a combination of both chemical and visual recognition cues was available. When given a choice of shoaling with same-sex groups,
females spent significantly longer with full-sibs rather than half-sibs, full-sibs rather than non-relatives and half-sibs
rather than non-relatives. Males spent significantly longer shoaling with full-brothers versus half-brothers, but showed no
other shoalmate preferences. Second, in the presence of only chemical cues, females did not discriminate among groups of different
levels of relatedness, but males showed a non-significant tendency to associate with full-sibs rather than non-relatives.
Male shoaling behaviour seemed to be more influenced by factors other than relatedness, e.g. intra-sexual competition. Finally,
I found that the shoaling preferences of females changed when exposed to groups of males. Females preferred to associate with
non-relatives rather than half-brothers and non-relatives rather than full-brothers. There was no significant difference in
the time spent with half-brothers versus full-brothers. Taken together, my results suggest that females have very good kin
recognition abilities. They prefer to shoal with female relatives but avoid male relatives, and so are able to balance the
benefits of nepotism and the costs of incest.
Received: 2 May 2000 / Revised: 26 July 2000 / Accepted: 30 July 2000 相似文献
118.
本文根据与青海省城乡居民生活能源消费相关的8个部门的能源消费数据,采用统计分析方法,从最终需求的角度评估了2000-2008年城乡居民生活能源消费及其碳排放。研究发现2000-2008年青海省城镇与农村居民生活用能在总量和人均水平上均相差很大,并且由此产生的碳排放是城镇居民远高于农村居民,其中,城镇居民生活用能主要集中在食品、娱乐教育文化服务、衣着3个部门,占总能源消费的61.02%,而农村居民生活用能主要集中在食品、居住和交通通讯3个部门,占总能源消费的71.77%。如果青海省农村居民能源消费水平达到青海省城镇居民能源消费的最低水平,会引起能源消费量及碳排量的急剧增加。 相似文献
119.
120.
如何有效激活农民主体性,激发人居环境整治中的群众参与是实现农村环境善治的重要议题。村庄调研发现,在当前国家资源向村庄密集输入的情况下,自上而下的单一环境供给方式既浪费资源,又难以满足居民诉求。动员村庄女性群体组织化参与是农村人居环境整治自下而上的群众动员和需求整合的有效方式。一方面,女性群体因其身份在村、关系在村,市场参与不足,成为村庄环境整治的潜在力量,与环境治理事务具有耦合性。另一方面,组织化参与为女性社会性身份的展演提供长效机制,利益吸纳成为激发女性参与的直接诱因。女性群体参与人居整治实践机制反映的是以农民为主体的农村环境治理需要抓住核心力量,对积极分子进行识别、激活和组织。 相似文献