黄河北徙与北宋城市适应方式探析

黄河变迁史上的第三次大改道导致黄河突发北徙,彻底改变了泛滥区城市的自然和人文环境,是开展复杂人地耦合系统研究的理想区域。利用水平横剖面法、数理统计与GIS手段相结合的方法,探索黄泛城市的数目、时空变化特征和适应性类型。结果表明：（1）黄河7个行河期的决溢泛滥,产生29座受灾城市;（2）受灾城市总体分布广泛,但又相对集中分布在黄河决口所形成的洪积扇顶部附近,地势低洼的冀中平原以及黄、御等河流交汇处;（3）黄泛城市主要呈现出避河患迁城、因河患省并、原址加固防御、直接湮废四种适应性类型,以避河患迁城型居多,占45%;（4）朝廷政策和城市规模是影响城市在黄河突发灾害下的空间分异和适应性举措的重要人文因素。黄泛区受灾城市具有重要的地方性保存和可持续发展演进模式。建议将其纳入“黄河流域生态保护和高质量发展”国家战略,作为讲好黄河故事的重要区域。     

宋至清荆江南岸分流四口的演变

在历史时期荆江地区的经济开发与江湖关系的演变历程中，分流诸口是极其重要的影响因素。以宋至清的志书为主要资料，立足于历史学的实证方法，以今荆江南岸存在的4个分流穴口，即虎渡口、调弦口、藕池口和松滋口为主要对象，考察四口在宋元明清时期的分塞情况，并对今人存在的一些认识进行了辨析。其中，虎渡河的形成时间说法不一，南宋以后，虎渡口逐渐形成稳定分流。调弦口自元代大德年间开浚后时开时塞，直至清朝才基本保持分流，1958年调关设置后此口渐废。藕池口早在五代时即已存在，北宋以后湮塞，直至1852年藕池堤溃不筑，藕池河再次形成。松滋河则在1869年以前由于黄家埠堤溃决而形成。研究表明，宋代以降，四口的分塞情况较为复杂，因此，考察荆江穴口分流与湮塞的历史变迁，厘清以往的相关歧见，将有助于更正确、客观地理解今天的人地关系、江湖关系的格局及其走向。     

Effects of Population Size on Singing Behavior of a Rare Duetting Songbird

Although the genetic and ecological effects of population declines in endangered species have been well studied, little is known of the social consequences. Changes in signaling behavior may result in disrupted communication and affect both reproductive and conflict‐resolution activities. The North Island Kōkako (Callaeas wilsoni) is an endangered, duetting (i.e., alternating, coordinated singing by mated pairs) songbird endemic to New Zealand temperate rain forests. Scattered populations (approximately 1500 individuals in 13 surviving and 11 translocated populations) in isolated conservation areas of different sizes have been rescued from extirpation and are currently recovering. We examined key song attributes of the Kōkako to assess whether population size or growth rate are related to song complexity, the reduction of which may compromise effective communication. We analyzed song repertoire size and phrase‐type sharing (i.e., Jaccard index of similarity), vocal performance (singing rates, song switching rates, and diversity of phrase types), and song syntactical characteristics (i.e., unpredictability in sequences of phrase types) in surviving and translocated populations (populations of approximately 19–250 territorial individuals). Population size was positively correlated with a population's song repertoire, song diversity, and switching of song phrase types and negatively correlated with shared phrase types and variation in syntactical structure of songs. Population growth rate correlated positively with pair repertoire size, population repertoire size, and singing rates during song bouts. As for solo‐singing species in fragmented landscapes, songs in the fragmented populations of Kōkako appear to be undergoing microevolution as occurs in island colonization events. Our results suggest that vocal changes in small populations could affect population establishment and growth, particularly in multiple‐source translocations. We believe measurement of vocal behavior could be used as a supplement to periodic population censuses to allow more frequent monitoring of population size. Efectos de la Conducta de Canto sobre el Tamaño Poblacional de una Ave Canora Rara     

Individual recognition of song repertoires in two wood warblers

We examined recognition of individual neighbors in hooded warblers (Wilsonia citrina) and Kentucky warblers (Oporornis formosus) by comparing responses to playbacks of neighbors' songs from appropriate and inappropriate boundaries of the subjects' territories. Kentucky warblers, which sing one song type each, responded more strongly to the songs of neighbors broadcast from incorrect than from correct boundaries. Hooded warblers use their repertoires of three to nine song types in two distinct modes of singing: repeat mode involves repeated presentation of one song type; mixed mode involves presentation of two or more song types in irregular sequence. Playbacks of neighbors' mixed-mode songs from appropriate and inappropriate boundaries indicated capabilities of individual recognition similar to those reported previously for repeat-mode songs (Godard 1991) and to those of Kentucky warblers. Repertoires of moderate size, therefore, have no pronounced influence on eventual recognition of individual neighbors in hooded warblers.     

Temporal patterning of within-song type and between-song type variation in song repertoires

In many songbird species, males sing a repertoire of distinct song types. Song sparrows typically are described as having repertoires of about a dozen song types, but these song types are themselves quite variable and some songs are produced that appear intermediate between two types. In this study we quantify the similarity between successive songs produced by song sparrows in order to determine if differences between song types are emphasized or deemphasized in bouts of continuous singing. In spite of the high degree of variation within song types and similarity between song types observed in this species, we show that transitions from one song type to the next are distinct as compared to transitions within sequences of the same type (Figs. 4 and 5). Variation does not accumulate across sequences of the same song type, and the average variation observed within a continuous sequence of the same song type is significantly less than is predicted from the total variation recorded for that type across many different bouts (Fig. 6). These results support the view that song sparrows include two levels of variation in their singing: differences between song types as is commonly observed in species with song repertoires, and an independent level of variation observed for songs of the same type.     

Use of trace element analysis of feathers as a tool to track fine-scale dispersal in birds

Tracking dispersal and migratory movements of animals over small and large spatial scales is a challenge. In birds, a promising yet underutilized tool is the trace elemental composition of feathers. The elemental profile of a feather may reveal information about the geographic origin of a bird provided that molting occurs on the breeding grounds and that elemental differences exist between breeding areas. Here, we explore the use of trace elemental composition in body feathers of the Puget Sound white-crowned sparrow Zonotrichia leucophrys pugetensis as a tool (1) to discriminate among birds collected in four different song dialect populations along a 400-km stretch of the Pacific Northwest coast and (2) to assign males singing nonlocal dialects in one population to potential natal populations. Inductively coupled plasma mass spectrometry detected 34 trace elements in sampled feathers and in a discriminant function analysis seven of these elements differed among the four source populations. Half of the six nonlocal dialect singers, who were likely to have immigrated into the focal population, were assigned to a population that matched their song dialect. Our study suggests that feather microchemistry is a promising tool for identifying geographic origins of dispersing birds over small geographic scales and in combination with other markers, such as song, may give insight into ecological and evolutionary processes.     

Early ontogenetic effects on song quality in the Bengalese finch (<Emphasis Type="Italic">Lonchura striata</Emphasis> var. <Emphasis Type="Italic">domestica</Emphasis>): laying order,sibling competition,and song syntax

Birdsong differs from other sexual traits in that the acquisition process involves learning. Especially in close-ended learning species like the Bengalese finch, conditions experienced during the critical song-learning period can have a profound influence on song quality. Therefore, to understand song evolution from a life-history perspective, we investigated early ontogenetic effects on song quality. In particular, we focused on maternal effects and sibling competition. In asynchronously hatching bird species, the age hierarchy among nestlings affects physical development due to competition for food; mothers may influence this competition by adjusting their investment in each egg according to its sequence in the laying order. To independently assess these effects, chicks of the Bengalese finch were cross-fostered so that the age hierarchies formed in fostered broods were independent of the laying order. Our results indicate that song quality partially reflects early ontogenetic conditions, whereas song duration and note-type repertoire were independent of either laying order or age hierarchy. The syntactical complexity of note order declined over the laying sequence. This finding suggests that the song learning ability is influenced by within-clutch variation in maternal investment toward eggs. Considering that song syntactical complexity is subject to female preference in the Bengalese finch, it is likely that maternal resource allocation strategies play a role in song evolution.