A geographic mosaic of evolutionary lineages within the insular endemic newt Euproctus montanus

Islands are hotspots of biodiversity, with a disproportionately high fraction of endemic lineages, often of ancient origin. Nevertheless, intra‐island phylogeographies are surprisingly scarce, leading to a scanty knowledge about the microevolutionary processes induced on island populations by Plio‐Pleistocene climatic oscillations, and the manner in which these processes contributed to shape their current genetic diversity. We investigated the phylogeography, historical demography and species distribution models of the Corsican endemic newt Euproctus montanus (north‐western Mediterranean). As for many island endemics, the continuous distribution of E. montanus throughout its range has hitherto been considered as evidence for a single large population, a belief that also guided the species' categorization for conservation purposes. Instead, we found a geographic mosaic of ancient evolutionary lineages, with five main clades of likely Pliocene origin (2.6–5.8 My), all but one restricted to northern Corsica. Moreover, the copresence between main lineages in the same population was limited to a single case. As also suggested by growing literature on intra‐island phylogeographic variation, it seems that the extensive use of simplifying assumption on the population structure and historical demography of island populations—both in theoretical and applicative studies—should be carefully reconsidered, a claim that is well exemplified by the case presented here.     

成都市区麻雀夜宿规律初步观察

2002年10月～2003年10月,对成都市区内一观察点麻雀的夜宿规律进行了观察。发现麻雀夜宿归巢时间、高峰时间、结束时间和清晨飞离时间有较强的规律,认为这是麻雀的生物节律决定的。     

Occupancy of Mountain Plover and Burrowing Owl in Colorado

Abstract: Concern over the decline of grassland birds has spurred efforts to increase understanding of grassland bird-habitat relationships. Previous studies have suggested that black-tailed prairie dogs (Cynomys ludovicianus) provide important habitat for shortgrass prairie avifauna, such as mountain plover (Charadrius montanus) and western burrowing owl (Athene cunicularia hypugaea), although such studies are lacking in Colorado (USA). We used methods to estimate occupancy (ψ) of mountain plover and burrowing owl on prairie dog colonies and other shortgrass prairie habitats in eastern Colorado. Mountain plover occupancy was higher on prairie dog colonies (ψ = 0.50, 95% CI = 0.36–0.64) than on grassland (ψ = 0.07, 95% CI = 0.03–0.15) and dryland agriculture (ψ = 0.13, 95% CI = 0.07–0.23). Burrowing owl occupancy was higher on active prairie dog colonies (ψ = 0.80, 95% CI = 0.66–0.89) compared with inactive colonies (ψ = 0.23, 95% CI = 0.07–0.53), which in turn was much higher than on grassland (ψ = 0.01, 95% CI = 0.00–0.07) and dryland agriculture (ψ = 0.00, 95% CI ψ 0.00–0.00). Mountain plover occupancy also was positively correlated with increasing amounts of prairie dog colony in the landscape. Burrowing owl occupancy was negatively correlated with increasing amounts of prairie dog colony in the surrounding landscape. Our results suggest that actions to conserve mountain plovers and burrowing owls should incorporate land management to benefit prairie dogs. Because managing for specific colony attributes is difficult, alternative management that promotes heterogeneity may ensure that suitable habitat is available for the guild of grassland inhabitants.     

两种近缘鸟种麻雀和山麻雀的咬合力比较

鸟类的咬合力受食性、种内竞争和捕食压力等多种生态因素的影响,可作为其生态适应特征的重要指标。但目前关于鸟类的咬合力及其影响因素却鲜有研究,为此,我们使用咬合力传感器,对同属的两个近缘鸟种,麻雀(Passer montanus)和山麻雀(P.cinnamomeus)的咬合力进行了比较研究。结果表明,山麻雀(n=12)的咬合力显著大于麻雀(n=59)(t=3.754,P0.01),但山麻雀(t=0.449,P0.05)和麻雀(Z=﹣1.198,P0.05)的雌雄个体间咬合力均无差异,同时,山麻雀的头宽(t=﹣3.713,P0.01)、头高(t=﹣5.405,P0.01)和喙宽(t=﹣6.201,P0.01)均显著大于麻雀。尽管个体的咬合力与其身体各参数指标无显著相关性,但在种间,头和喙的大小可能是影响两者咬合力的重要因素,由于两者的一些生态适应特征可通过头大小和喙型体现,推测两者生境和食性的差异可能是影响其咬合力大小的主要原因。     

城市化对城市麻雀栖息地利用的影响:以北京市为例

本文以北京市为例研究了城市化水平不同的8个区域中麻雀(Passermontanus)的数量分布现状以及影响麻雀分布的栖息地因子。结果表明,越冬期和繁殖期的麻雀数量均与城市化程度呈显著的负相关关系;城市化程度高的城市中心商业区、高层居民区和城市主干道中的麻雀数量均很少;城市化程度较低的城乡结合区、公园、城市的平房区及古建筑区域中麻雀数量均较多;高校校园和低层楼房居民区,虽然城市化程度相对较高,但由于植被较丰富,麻雀数量也较多。平房面积、针叶树数量、阔叶树数量、空调数量、高层楼房的面积、硬化地面的面积、人流量及车流量是影响麻雀栖息地利用的重要因素。其中平房面积、针叶树、阔叶树、空调的数量增加,可为麻雀提供栖息条件而有利于麻雀的利用;硬化地面的面积、高层楼房的面积、人流量及车流量的增加,由于减少了杂草等麻雀的食物来源并增加了干扰,不利于麻雀的利用。结果表明,虽然麻雀是一个适应人类生活环境的物种,但在快速的城市化变迁中,它已表现出对高度城市化环境的不适应。在城市的规划与建设中,应考虑到为以麻雀为代表的城市鸟类提供生存必要的植被和繁殖场所,构建人鸟和谐共存的生态城市。     

温度和光周期驯化对树麻雀消化道形态特征和能量预算的影响

为探讨温度和光周期驯化对树麻雀消化道形态特征和能量预算的影响,以不同环境温度(5℃和25℃)、不同光周期(16L∶8D和8L∶16D)的4组树麻雀进行为期4周的人工气候箱驯化,并对驯化后的4组树麻雀消化道形态特征各指标以体质量为协变量,采用温度、光周期双因素协方差分析和组间进行单因素协方差分析及进行Tukey HSD比较。结果表明,温度降低或光周期缩短导致消化道长度极显著增加;反之,则缩短。温度显著影响消化道干组织质量;温度和光周期的交互作用对消化道净鲜质量和干组织质量的影响显著;总消化道和各器官的长度(直肠长度除外)、质量均存在明显的组间差异。可见,不同的温度或光周期可引起树麻雀消化道形态结构和功能能力相应的适应性变化,消化道各器官长度和质量的改变与其个体的摄能需求密切相关,消化道各器官功能能力和器官能耗之间高投资高收益的能量预算是个体适合度与环境压力之间能量预算的结果。     

Evolution in a tropical archipelago: comparative phylogeography of Philippine fauna and flora reveals complex patterns of colonization and diversification

An unusual geological setting and a high level of endemism makes the Philippine islands of great interest to biogeography. These islands lie adjacent to the continental (Sunda) shelf, yet the majority of the islands have never been directly attached to the mainland. Existing hypotheses of colonization and diversification processes have been tested across multiple taxa, but only in ahistorical contexts. We present explicit phylogenetic predictions based on these hypotheses, and then test them using new molecular datasets for four Philippine birds. Two proposed colonization routes to the northern Philippines (from mainland Asia and Palawan) are difficult to differentiate from each other, except on the basis of outgroup, as are the two routes from the south (Sulu archipelago and Sulawesi). We find unique colonization and diversification patterns for each taxon. These results contrast with expectations from Pleistocene geography, with Luzon and Mindoro indistinguishable genetically, and Negros and Panay are often nonsister taxa. Combining these data with a literature search for studies addressing these patterns, Philippine organisms shows some evidence for each proposed colonization route but the greatest support is for the two routes from Borneo. Many taxa exhibit multiple colonization events using several of these routes, contrasting with past assumptions of single colonization events. Island‐by‐island differentiation within the Philippines follows, with patterns reflecting colonization patterns rather than Pleistocene geography, particularly for highland species. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 95 , 620–639.     

Islands within an island: Population genetic structure of the endemic Sardinian newt,Euproctus platycephalus

The identification of historic and contemporary barriers to dispersal is central to the conservation of endangered amphibians, but may be hindered by their complex life history and elusive nature. The complementary information generated by mitochondrial (mtDNA) and microsatellite markers generates a valuable tool in elucidating population structure and the impact of habitat fragmentation. We applied this approach to the study of an endangered montane newt, Euproctus platycephalus. Endemic to the Mediterranean island of Sardinia, it is threatened by anthropogenic activity, disease, and climate change. We have demonstrated a clear hierarchy of structure across genetically divergent and spatially distinct subpopulations. Divergence between three main mountain regions dominated genetic partitioning with both markers. Mitochondrial phylogeography revealed a deep division dating to ca. 1 million years ago (Mya), isolating the northern region, and further differentiation between the central and southern regions ca. 0.5 Mya, suggesting an association with Pleistocene severe glacial oscillations. Our findings are consistent with a model of southward range expansion during glacial periods, with postglacial range retraction to montane habitat and subsequent genetic isolation. Microsatellite markers revealed further strong population structure, demonstrating significant divergence within the central region, and partial differentiation within the south. The northern population showed reduced genetic diversity. Discordance between mitochondrial and microsatellite markers at this scale indicated a further complexity of population structure, in keeping with male‐biased dispersal and female philopatry. Our study underscores the need to elucidate cryptic population structure in the ecology and conservation strategies for endangered island‐restricted amphibians, especially in the context of disease and climate change.     

Using priority to food access: fattening strategies in dominance-structured willow tit (Parus montanus) flocks

We studied changes in body mass in response to priority to foodaccess by repeatedly weighing free-living willow tits in dominance-structuredflocks. Priority to food access did not correlate to eitheracquisition rate or net turnover of body reserves, but subordinateswith low food availability had larger body reserves than dominants.Removal experiments suggest a causal relationship between rankand the size of reserves. Body reserves of subordinates decreasedwhen their access to food increased after the dominant was removed.Low variability in body mass of subordinates shows that theydo not maintain large reserves in response to uncertain acquisitionof food. Rather, large reserves of low-rank individuals couldserve as insurance for conditions with increasing requirements.Under such conditions, dominants are more likely to claim theirpriority to food, and subordinates would not be able to increasetheir body reserves by feeding.     

Mountain Plovers in Oklahoma: distribution, abundance, and habitat use

ABSTRACT.   Mountain Plover ( Charadrius montanus ) populations are inefficiently sampled by Breeding Bird Surveys. As a result, targeted sampling of select populations of this species (with an estimated global population of 11,000–14,000 birds) can be valuable. Our objectives were to determine the breeding distribution and estimate the size of the Mountain Plover population in Oklahoma. We conducted a randomized point count survey in an area where Mountain Plovers were previously known to breed and conducted additional surveys over a larger area to better delimit the distribution. We used a removal model to estimate detection probability for raw counts obtained from 1104 point counts in 2004 and 2005, and derived a state-level population estimate using the detection-adjusted counts. Mountain Plovers used flat, bare, cultivated fields for nesting, and their distribution was closely tied to the presence of clay loam soils. We estimated that at least 68–91 Mountain Plovers bred in Oklahoma in 2004–2005. The low breeding density we observed may be due to the location of our study area near the southeastern edge of the breeding range of these plovers, the low-quality habitat provided by cultivated landscapes, or a combination of factors. Because the number of birds is small, the status of the Oklahoma population is not likely to have a large effect on the global population. However, additional information is needed to help determine if cultivated landscapes represented population sources or sinks.