latitude

Latitude
  • 文章类型: Journal Article
    作为一种潜在的反掠夺性防御结构,海洋钙化物的贝壳装饰通常用于理解捕食者与猎物之间相互作用的宏观协同进化。通常认为,海洋钙化剂的外壳装饰复杂性随纬度和水深而呈负向变化。在本文中,我们使用最新的全球腕足动物数据库探索了贝壳装饰与纬度/测深之间的关联。我们发现(1)~59%的活体腕足类物种的特征是光滑的贝壳,(2)没有统计学上显著的线性趋势,无论是积极的还是消极的,在装饰指数和纬度之间,也没有水深。这两个发现对于活着的腕足动物来说都是令人困惑的,因为它们与化石腕足动物的模式形成了鲜明的对比,后者,尤其是古生代腕足动物,已知表现出(1)更大的装饰多样性和(2)(至少在已研究的地质时期)存在装饰复杂性的线性纬度梯度。探索了为什么活着的腕足动物具有如此高比例的光滑或弱装饰贝壳并且未能表现出明确的线性纬度装饰梯度的原因,这些原因与许多潜在因素有关,而不仅仅与捕食压力有关。其中,最合理的因素似乎是神秘的(避难所型)栖息地(例如,深水,寒冷的极地地区,和海底岩洞),由于它们的低代谢,活的腕足动物已经适应了,捕食压力低的地方,允许腕足动物制定捕食者回避策略,而不必制造坚固的贝壳装饰以在原本高度参与的捕食者-猎物全球海洋生态系统中生存。
    As a potential anti-predatory defensive structure, the shell ornamentation of marine calcifiers is usually used to understand the macro coevolution of the interactions between predators and preys. Marine calcifiers\' shell ornamentation complexity is generally believed to vary negatively with latitude and water depth. In this paper, we explored the association between shell ornamentation and latitude/bathymetry using the latest global database of living brachiopods. We found that (1) ~59% of living brachiopods species are characterized by smooth shells and that (2) there is no statistically significant linear trend, either positive or negative, between the ornamentation index and latitudes nor with water depths. Both findings are puzzling for living brachiopods as they are sharply contrasted to the patterns of fossil brachiopods whereby the latter, especially Paleozoic brachiopods, are known to exhibit (1) a much greater ornamentation diversity and (2) (at least for the geological periods that have been studied) a linear latitudinal gradient of ornamentation complexity existed. The reasons why living brachiopods have such a high proportion of smooth or weakly ornamented shells and fail to demonstrate an unequivocal linear latitudinal ornamentation gradient were explored and are linked to a multitude of potential factors rather than uniquely only to the predation pressure. Among these, the most plausible factor seems to be the cryptic (refuge-type) habitats (e.g., deep waters, cold polar regions, and submarine rock caves) that living brachiopods have been adapted to due to their low metabolism, where predation pressure is low, allowing brachiopods to enact the predator avoidance strategy rather than having to manufacture robust shell ornamentation to survive in an otherwise highly engaged predator-prey global marine ecosystem.
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  • 文章类型: Journal Article
    It is commonly accepted that species should move toward higher elevations and latitudes to track shifting isotherms as climate warms. However, temperature might not be the only limiting factor determining species distribution. Species might move to opposite directions to track changes in other climatic variables. Here, we used an extensive occurrence data set and an ensemble modelling approach to model the climatic niche and to predict the distribution of the seven baobab species (genus Adansonia) present in Madagascar. Using climatic projections from three global circulation models, we predicted species\' future distribution and extinction risk for 2055 and 2085 under two representative concentration pathways (RCPs) and two dispersal scenarios. We disentangled the role of each climatic variable in explaining species range shift looking at relative variable importance and future climatic anomalies. Four baobab species (Adansonia rubrostipa, Adansonia madagascariensis, Adansonia perrieri¸ and Adansonia suarezensis) could experience a severe range contraction in the future (>70% for year 2085 under RCP 8.5, assuming a zero-dispersal hypothesis). For three out of the four threatened species, range contraction was mainly explained by an increase in temperature seasonality, especially in the North of Madagascar, where they are currently distributed. In tropical regions, where species are commonly adapted to low seasonality, we found that temperature seasonality will generally increase. It is, thus, very likely that many species in the tropics will be forced to move equatorward to avoid an increase in temperature seasonality. Yet, several ecological (e.g., equatorial limit, or unsuitable deforested habitat) or geographical barriers (absence of lands) could prevent species to move equatorward, thus increasing the extinction risk of many tropical species, like endemic baobab species in Madagascar.
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  • 文章类型: Journal Article
    参与式方法,比如社区摄影,可以让公众参与社会和科学利益问题,同时帮助推进对生态模式和过程的理解。我们结合了从社区来源提取的数据,空间清晰的照片,以及2018年育空地区实地调查的研究结果,加拿大,为了评估山地山羊(Oreamnosamericanus)的冬季大衣蜕皮模式和物候,一个冷适应,高山哺乳动物。利用社区科学门户网站iNaturalist和CitSci,在不到一年的时间里,我们收集了一个数据库,其中包含近七百张独特的照片,这些照片跨越了北纬37.6°至61.1°北纬0至4333m之间约4,500公里的高度。使用统计方法处理不完整的数据,社区科学数据集中的一个常见问题,我们确定了内在因素(性别和后代的存在)和广泛的环境因素(纬度和海拔)对蜕皮发生和速率的影响,并将我们的发现与已发表的数据进行了比较.脱落发生在5月29日至9月6日之间的3个月期间。性别和后代对蜕皮时间的影响在社区来源和育空地区的数据之间以及在艾伯塔省中西部的长期研究地点对野生山羊的发现之间是一致的,加拿大。雄性先蜕皮,其次是没有后代的雌性(4.4天后,粗粒,地理范围广泛的社区科学样本;29.2天后,在我们细粒度的育空地区样本中),最后是有新孩子的女性(6.2;21.2天后,分别)。后来在海拔较高的地区脱落,在北纬地区脱落更快。我们的发现为采用社区摄影来研究有关生态事件发生时间的广泛问题奠定了基础。以及对可能的气候驱动因素的性别差异。此外,社区摄影可以帮助激发公众参与环境和户外活动,特别是关于标志性野生动物。
    Participatory approaches, such as community photography, can engage the public in questions of societal and scientific interest while helping advance understanding of ecological patterns and processes. We combined data extracted from community-sourced, spatially explicit photographs with research findings from 2018 fieldwork in the Yukon, Canada, to evaluate winter coat molt patterns and phenology in mountain goats (Oreamnos americanus), a cold-adapted, alpine mammal. Leveraging the community science portals iNaturalist and CitSci, in less than a year we amassed a database of almost seven hundred unique photographs spanning some 4,500 km between latitudes 37.6°N and 61.1°N from 0 to 4,333 m elevation. Using statistical methods accounting for incomplete data, a common issue in community science datasets, we identified the effects of intrinsic (sex and presence of offspring) and broad environmental (latitude and elevation) factors on molt onset and rate and compared our findings with published data. Shedding occurred over a 3-month period between 29 May and 6 September. Effects of sex and offspring on the timing of molt were consistent between the community-sourced and our Yukon data and with findings on wild mountain goats at a long-term research site in west-central Alberta, Canada. Males molted first, followed by females without offspring (4.4 days later in the coarse-grained, geographically wide community science sample; 29.2 days later in our fine-grained Yukon sample) and lastly females with new kids (6.2; 21.2 days later, respectively). Shedding was later at higher elevations and faster at northern latitudes. Our findings establish a basis for employing community photography to examine broad-scale questions about the timing of ecological events, as well as sex differences in response to possible climate drivers. In addition, community photography can help inspire public participation in environmental and outdoor activities specifically with reference to iconic wildlife.
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