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1.
Although the population history and social organization of the prehistoric Pueblo Indians of the American Southwest have received attention in the archaeological literature, little research on this topic has been conducted by biological anthropologists. Here, we examine postmarital residence at two ancestral Tewa Indian pueblos located in north-central New Mexico using determinant ratio analysis. In addition, we examine genetic relationships among pueblos, as well as levels of within-pueblo heterogeneity due to gene flow from extraregional sources, or regional aggregation. Results from determinant ratio analysis indicate greater within-pueblo male variation, consistent with matrilocal residence for at least one Tewa pueblo. Less than expected heterogeneity at two pueblos suggests that endogamy might have been practiced among some prehistoric Tewa pueblos. Gene flow from extraregional sources is indicated for two different pueblos by greater than expected within-group heterogeneity. Distance matrix correlation analyses indicate little if any relationship between phenotypic and geographic distances, suggesting that geography was not the primary basis of gene flow or mate exchange. The weak relationship between phenotypic and geographic distances may be the combined effects of endogamy at some pueblos, nonrandom extraregional gene flow or migration at other pueblos, and limited nonproximity-dependent regional gene flow or migration among pueblos, possibly structured on ritual exchange networks based on medicine society affiliation.  相似文献   

2.
Summary Comparisons of prehistoric (A.D. 1100–1400) and extant cricetine-dominated rodent faunas from two locations in New Mexico and one in Arizona reveal temporal changes in both species diversity and taxonomic composition. The archaeological context of the prehistoric faunas permitted them to be dated rather accurately; paleoenvironmental inferences generated from other materials recovered in the excavations such as pollen samples, agricultural remains, and tree-ring specimens provided evidence about prehistoric environmental conditions in the study areas. Both richness and evenness components of diversity are lower in the present day faunas than in their prehistoric counterparts. At the beta (between-habitat or valley-wide) level of diversity the increased prehistoric species richness as well as the nature of the differences in present and prehistoric taxonomic composition can be accounted for by small climatic shifts which were occurring between A.D. 1100 and 1300 in the Southwest and the resultant biogeogrphic responses of certain rodent species. Alpha (or within-habitat) diversity is similar for all analyzed faunas. This suggests basic similarities in very local species packing despite observed spatial and temporal variation in valley-wide diversities. Environmental changes stemming from climatic shifts provide a reasonable explanation of the observed patterns of rodent species occurrence and diversity. Habitat destruction resulting from agricultural practies of prehistoric human populations appears to have had only a limited impact on these rodent communities.  相似文献   

3.
Richness and abundance of birds in riparian forest belts of varied breadths at the Sesesmiles river microwatershed, Copan, Honduras. Riparian forests protect many species of plants and animals. We studied bird communities in riparian forest belts of the Sesesmiles river microwatershed, Copan, Honduras (140 degrees 43' 12" - 140 degrees 58' 35" N, 88 degrees 53' 23" - 89 degrees 14' 17" W). The main goal was to explore the effects of belt breadth on the richness and abundance of avian species visiting these forests. We selected 20 belts, and randomly established 30 observation points to monitor bird presence in the dry (March-April 2005) and rainy (June-July 2005) season (N= 60 observations). A total of 1,294 birds belonging to 145 species were recorded. Bird diversity was significantly correlated to the breadth of the riparian belts, with a greater number of species and individuals in belts 50 m wide or wider. Insectivorous and nectarivorous birds were the most abundant guilds. All bird species identified depend to some degree on riparian forests and are affected by belt breadth. Riparian belts over 50 m should be kept or established in order to conserve bird populations within agricultural and fragmented landscapes in similar tropical areas.  相似文献   

4.
I examined the effect of riparian forest restoration on plant abundance and diversity, including weed species, on agricultural lands along the Sacramento River in California (United States). Riparian forest restoration on the Sacramento River is occurring on a large‐scale, with a goal of restoring approximately 80,000 ha over 160 km of the river. In multiuse habitats, such as the Sacramento River, effects of adjoining habitat types and movement of species across these habitats can have important management implications in terms of landscape‐scale patterns of species distributions. Increased numbers of pest animals and weeds on agricultural lands associated with restored habitats could have negative economic impacts, and in turn affect support for restoration of natural areas. In order to determine the distribution and abundance of weeds associated with large‐scale restoration, I collected seed bank soil samples on orchards between 0 and 5.6 km from adjacent restored riparian, remnant riparian, and agricultural habitats. I determined the abundance, species richness, and dispersal mode of plant species in the seed bank and analyzed these variables in terms of adjacent habitat type and age of restored habitat. I found that agricultural weed species had higher densities at the edge of restored riparian habitat and that native plants had higher densities adjacent to remnant riparian habitat. Weed seed abundance increased significantly on walnut farms adjacent to restored habitat with time since restored. I supply strong empirical evidence that large areas of natural and restored habitats do not lead to a greater penetration of weed species into agricultural areas, but rather that weed penetration is both temporally and spatially limited.  相似文献   

5.
Summary 1. Many studies have shown negative effects of river drying on in‐stream animals. However, the influence of river drying on riparian animals remains poorly studied. We examined ground‐dwelling riparian arthropod assemblages along a drying section of the semi‐arid San Pedro River in southeastern Arizona, U.S.A. 2. We found strong differences in assemblage composition, taxon diversity and the abundance of key taxa between dry and flowing sites, with higher diversity and abundance of most taxa at flowing sites. 3. Changes in assemblage composition, taxon diversity and abundance of representative taxa were associated with a combined measure of water availability that included distance to water and type of water. Other environmental variables showed a weaker association with changes in these arthropod assemblages. 4. Thus, we found evidence that desert riparian arthropods are sensitive to river drying and to reduction in water resources. Increases in drying along this river may reduce the diversity and the abundance of many groups of ground‐dwelling arthropods, leading to marked shifts in community composition.  相似文献   

6.
Agricultural practices lead to losses of natural resources and biodiversity. Maintaining forests alongside streams (riparian forest strips) has been used as a mechanism to minimize the impact of clearing for agriculture on biodiversity. To test the contribution of riparian forest strips to conserve biodiversity in production landscapes, we selected bats as a biodiversity model system and examined two dimensions of diversity: taxonomic and functional. We compared bat diversity and composition in forest, with and without stream habitat, and in narrow forest riparian strips surrounded by areas cleared for agriculture. We tested the hypothesis that riparian forest strips provide potential conservation value by providing habitat and serving as movement corridors for forest bat species. Riparian forest strips maintained 75% of the bat species registered in forested habitats. We found assemblage in sites with riparian forest strips were dominated by a few species with high abundance and included several species with low abundance. Bat species assemblage was more similar between sites with streams than between those sites to forests without stream habitat. These results highlight the importance of stream habitat in predicting presence of bat species. We registered similar number of guilds between forest sites and riparian forest strips sites. Relative to matrix habitats, stream and edge habitats in riparian forest strips sites were functionally more diverse, supporting our hypothesis about the potential conservation value of riparian forest strips. Results from this study suggest that maintaining riparian forest strips within cleared areas for agricultural areas helps conserve the taxonomic and functional diversity of bats. Also, it provides basic data to evaluate the efficacy of maintaining these landscape features for mitigating impacts of agricultural development on biodiversity. However, we caution that riparian forest strips alone are not sufficient for biodiversity maintenance; their value depends on maintenance of larger forest areas in their vicinity.  相似文献   

7.
Habitat degradation through agricultural land use is the major factor threatening lotic ecosystems. Although black flies are major components of these ecosystems, the impact of agricultural land use on species diversity and species assemblages has been largely ignored in tropical streams of the Oriental region. The objectives of this study are to examine patterns of species distribution and species richness and to compare black fly species richness and species assemblages in forest and agricultural streams in Thailand. A total of 143 collections were made from 70 stream sites between June 2007 and May 2008. Whereas 19 black fly species found in these collections were all found in forest sites, only 13 species were found in agricultural sites. High species richness was associated with larger, faster, and cooler streams with larger streambed particles and the presence of riparian trees. Logistic regression analyses revealed that stream size, velocity, and riparian vegetation are among the most important factors determining patterns of spatial distribution. The results are largely consistent with studies in other zoogeographic regions, suggesting the existence of general rules for black fly species distributions. Comparisons of the physicochemical conditions between forest and agricultural streams indicated that streams in agricultural areas are warmer, with higher conductivity and fewer riparian trees. Species richness was significantly higher in forest than in agricultural streams (t = 3.61, P < 0.001). Streams in forest areas were predominantly occupied by S. siamense (73%) but other species were also found at a relatively high frequency (>20%) of the sampling sites. In contrast, streams in agricultural areas were predominantly occupied by S. aureohirtum (>80%) among the sole black fly species at 27% of the sites. The results indicate that agricultural land use has a significantly detrimental impact on black fly diversity and species assemblages. Handling editor: D. Dudgeon  相似文献   

8.
Riparian vegetation performs important ecosystem functions, since it maintains regional biodiversity and provides a range of environmental services. However, anthropogenic activity, land use type, and edge effects are factors that modify the riparian species assemblage and properties. The present study analyzes the influence of adjacent land use on the structure and diversity of riparian vegetation in four hydrographic regions that form the watershed of the river Duero, in the state of Michoacán, Mexico. Using a survey of woody plants of dbh ≥ 2.5 cm in ten different 0.1 ha sites, we found that the average number of stems and individuals was lower under agricultural (AGR) and urban (URB) land use, compared to forested areas (FOR). The proportion of multistemmed plants differs among land uses: this value was greater in AGR than in the FOR and URB categories. This proportion also differed among the four hydrographic regions. The land use type FOR presented the highest alpha and beta diversity, with a high number of native species occurring only in areas defined by this land use. The results indicate that the category FOR plays an important role in the conservation of regional flora and is a possible source of germplasm for restoration programs in sites degraded by human disturbance. This study shows how anthropogenic activities affect riparian vegetation and highlights the importance of further study of this ecosystem to apply sustainable management strategies that are compatible with its conservation.  相似文献   

9.
Width is an essential element of the spatial configuration of riparian forests and may be fundamental in determining their corridor function. In the present study we tested the effect of forest width on floristic structure (tree species composition and diversity) in 15 fragments of riparian forest in an agricultural fragmented landscape of SE Brazil. All these fragments were chosen in a geomorphological homogeneous river reach under similar soil, topographic and human disturbance conditions in order to minimize the influence of these factors. The forest widths considered ranged from 30 to 650 m. The results showed that total species richness and climax species richness were significantly greater when we consider larger fragments, as has been observed in other studies. Nevertheless, species diversity and evenness were not significantly correlated with forest width. The analysis of species composition showed that the narrowest fragments were characterized by species well adapted to temporary flood conditions, while medium and wide fragments showed a composition typical of drier upland areas. Therefore, the effect of forest width on floristic structure appears to be more strongly linked to the effect of river floods in the case of the fragments studied. The existence in riparian corridors of a drier forest, in general richer and more diversified than the annually flooded forest, seems to favor the maintenance of regional species diversity in fragmented landscapes.  相似文献   

10.
In the 25 years since the first DNA sequences were obtained from the extinct moa, ancient DNA analyses have significantly advanced our understanding of New Zealand's unique fauna. Here, we review how DNA extracted from ancient faunal remains has provided new insights into the evolutionary histories and phylogenetic relationships of New Zealand animals, and the impacts of human activities upon their populations. Moreover, we review how ancient DNA has played a key role in improving our ability to taxonomically identify fragmentary animal remains, determine biological function within extinct species, reconstruct past faunas and communities based on DNA preserved in sediments, resolve aspects of the ecology of extinct animals and characterising prehistoric parasite faunas. As ancient DNA analyses continue to become increasingly applied, and sequencing technologies continue to improve, the next 25 years promises to provide many more exciting new insights and discoveries about New Zealand's unique fauna.  相似文献   

11.
To determine use of riparian habitats by birds in the northern coniferous forest of British Columbia, we censused birds and vegetation along 500 m transects placed parallel and perpendicular to three second-order streams. Censuses were conducted during spring, summer, autumn, and winter to investigate how use of riparian habitat changed seasonally. Stream-side riparian zones were characterized by a dense understorey of deciduous vegetation not found in the upslope forest. Nine bird species preferred the riparian understorey for breeding, six preferred it only during migration. Neotropical migrants (16 of 46 species) were more closely associated with stream-sides than year-round residents (11 species). Some breeding birds (five species) were significantly negatively associated with riparian habitats. The density of riparian birds declined with distance upstream but did not decline up to 250 m away from the stream. The more extensive riparian areas downstream supported a greater density of birds in all seasons compared to upstream areas, but more species only in spring and autumn. Species that nested in non-riparian areas in summer used riparian habitat in autumn, making riparian corridors in the northern coniferous forest important during migration. Maintaining both riparian and upslope habitats is necessary to preserve species diversity al the landscape level.  相似文献   

12.
Optimal sampling area for biodiversity monitoring is a classical scientific topic for the biodiversity research in view of the cost, human resources and ecological significance. However, how much sampling area is enough for biodiversity monitoring in riparian area, the ecotone among freshwater and terrestrial system? Whether the optimal sampling areas are different among ecoregions? To explore these scientific questions, the minimum sampling area of riparian herbs was studied in Taizi river, Liaoning province, China. The species-area relationship was modeled using average species richness in the same area (2.25, 4.5, 6.75 and 9 m2) of 55 sites distributed along riparian zone of Taizi river water course. The power model S = aA b modeled best, and was selected to fit species-area curves. The minimum sampling areas for total species and dominant families were calculated via the selected model and corresponding estimated species richness. Results showed that the minimum sampling areas (MSAs) for herbs diversity monitoring in whole basin, highland ecoregion, midland ecoregion and lowland ecoregion of Taizi river were 12.82, 12.06, 13.46 and 13.08 m2,respectively. The MSAs of dominant families Compositae species and Graminale species were similar to that of total species. The minimum sampling area of Taizi river riparian zone was similar to other temperate riparian grassland and wet grassland, larger than dry grassland and salt meadow. So we did not need consider ecoregion difference for temperate riparian herbs diversity monitoring in watershed scale.  相似文献   

13.
The study of coprolites (desiccated feces) is recognized as a viable method for analyzing parasitism of prehistoric peoples. Eight species of helminth parasites, including nematodes, cestodes, and acanthcephalans, have been recovered from archaeological sites on the Colorado Plateau. The comparative analysis of parasitological findings illustrates the effects of changing subsistence strategies and varying life-style on prehistoric human parasitism. This comparative study is based on the analysis of coprolites recovered from one Archaic hunter-gatherer site and two Anasazi agricultural villages. Hunter-gatherers are represented by coprolites from Dust Devil Cave in south-eastern Utah. Coprolites of prehistoric agriculturalists from Antelope House in Canyon de Chelly, Arizona, and from Salmon Ruin in northwestern New Mexico were studied. The results demonstrate that helminth parasitism increased with the advent of agriculture. Between the agricultural sites, differences in patterns of excreta disposal, foraging behavior, and local ecology resulted in pronounced variations in both percentage of coprolites containing parasite remains and the number of parasite species represented.  相似文献   

14.
榆林火石梁遗址动物遗存研究   总被引:3,自引:0,他引:3  
本文对榆林新机场火石梁遗址出土的动物骨骼进行了系统的分类和研究。动物骨骼属哺乳动物18种,鸟类1种;其中以羊骨数量最多,约占总数的60%,不同于任何一个关中新石器遗址。根据对出土的动物骨骼和文化层堆积分析结果表明:遗址周围的自然景观以草原为主,草原上有各种羊、牛、马、兔等食草动物,不远处有一定面积的森林、疏林、灌丛及沙漠,其间有虎、猫等食肉动物和各种鹿类动物及羚羊的出没。动物中虎、梅花鹿、马鹿、狍、羚羊、岩羊现已在此绝迹,其余为现仍生活在该地区的种类。  相似文献   

15.
修晨  郑华  欧阳志云 《生态学报》2016,36(15):4689-4698
强烈的人类活动对自然生境的扰动促进了外来植物侵入河岸带,但不同类型的人类活动干扰对外来植物的影响有所不同。按照不同人类活动干扰类型设置了山峡段、平原段和城市段,通过比较河段间河岸带外来植物群落特征的差异,探讨不同人类活动干扰类型对河岸带外来植物群落的影响。结果表明:(1)永定河河岸带共有维管束植物27科72属101种,外来植物13科28属29种。外来种比例高达28.7%,其中82.4%的国外外来种来自美洲和亚洲。(2)不同河段间的外来植物群落的物种构成和优势度呈现出显著性差异。外来种比例由山峡段的20.9%,上升至平原段和城市段的30.2%和25.5%;而优势度由12.1%,分别上升至13.4%和17.5%。(3)不同河段间的外来植物群落生活型结构有显著性差异。多年生草本植物在山峡段比例最高,达到66.7%,在平原段和城市段较低,分别为46.2%和30.8%;而一年生草本植物在城市段比例最高,达到69.2%,在平原段和山峡段较低,分别为53.8%和33.3%。(4)平原段属于农业干扰类型,其河岸带外来植物主要以农业类杂草为主,如禾本科的假稻(Leersia japonica)和菊科的钻叶紫菀(Aster subulatu);城市段是城市干扰类型,外来植物中入侵种比例和优势度较高,典型入侵种为反枝苋(Amaranthus retroflexus)和牛筋草(Eleusine indica)等。北京永定河不同河段河岸带外来植物的种类构成特点,反映了河岸带外来植物受快速城市化、农业活动等不同人类活动干扰的影响呈逐渐扩大的趋势。  相似文献   

16.
Riparian areas are often the only green areas left in urban and suburban landscapes, providing opportunities for conservation and connectivity of both aquatic and terrestrial organisms. While city planners and land managers often tout the importance of riparian networks for these uses, it is not well established if urban riparian plant communities are actually functioning as connected assemblages. Furthermore, urban riparian zones are well known to be highly invaded by non-native plant species and may be functioning to increase the spread of non-native species across the landscape. Here we examine connectivity of plant assemblages in riparian networks within an extensively urbanized landscape. We sampled riparian plant communities at 13 sites along three second-order streams of the Rahway River watershed, New Jersey. We also characterized propagule dispersal at each site by sampling litter packs on the river banks five times between March–October 2011 and identifying germinants from litter packs after cold stratification. Species turnover of both riparian and litter vegetation was more strongly associated with flow distance, particularly for native species, indicating that riverine systems are important for promoting connectivity of native plant assemblages in urban landscapes. However, non-native germinants significantly dominated propagule dispersal along the stream reaches, particularly early in the growing season, suggesting spread utilizing the river system and preemption may be an important mechanism for invasion success in this system. Our data show that management of invasive species should be planned and implemented at the watershed scale to reduce spread via the river system.  相似文献   

17.
Agricultural habitats are assumed to be biodiversity refuges. However, some studies treat agricultural land management as a cause of the biodiversity decline, to which habitat loss and heterogeneity may contribute. Between the crops, the successional habitats appear – ruderal plant communities and bush areas. Their influence on farmland biodiversity is unknown. This research assessed the impact of spatial relationships between agricultural areas, semi-natural meadows and successional habitats on the bird species richness, Shannon diversity index, and Faith’s phylogenetic diversity index. An additional habitat variable was the presence of weeds, i.e., invasive Caucasian hogweeds Heracleum sp., treated as crops in the past. The birds and habitats research was on 74 sites set in pairs (invaded vs control) in south-eastern Poland. Results showed that birds assembling in agricultural and semi-natural areas were more diverse and contained protected farmland species, while birds appearing in overgrown habitats (i.e., successional and invaded) were clumped with their habitat requirements. In the presence of plant invaders, ruderal habitats negatively affected the bird phylogenetic diversity index. In invaded sites, bush areas had no positive effects on the Shannon diversity index and species richness of birds, in contrast with control sites. The presented research suggests the need to re-evaluate the importance of successional non-crop habitats considered positive in agricultural landscapes if those habitats develop in areas with plant invasion.  相似文献   

18.
Riparian habitat supports the highest density and diversity of songbirds in Western North America despite covering less than 1% of the land area. Widespread destruction and degradation of riparian habitat, especially by livestock grazing, has led to habitat restoration efforts. In 2000, restoration activities in the form of permanent and seasonal exclusion of livestock from riparian areas were initiated to improve habitat for the endangered Western Yellow‐breasted Chat (Icteria virens auricollis) population, which is dependent on early successional shrub habitat for nesting, in the Okanagan Valley of British Columbia, Canada. We assessed the effectiveness of livestock exclusion by examining temporal changes in the abundance, richness, and breeding performance of birds in restoration and reference sites. The abundance of W. Yellow‐breasted Chats significantly increased between 2002 and 2013 in areas where restoration activities occurred. However, restoration did not have significant effects on the abundance, richness, or breeding performance of other riparian birds at the restoration sites independent of temporal changes that occurred at reference sites. Our results provide evidence that limiting livestock grazing in temperate riparian areas can lead to recovery of endangered riparian songbirds that rely on early successional shrub habitat but may have limited effects on common species that are not strictly reliant on this habitat.  相似文献   

19.
Macroinvertebrates were sampled from 15 sites along a dry-land river in northwestern Zimbabwe to assess biotic responses to land use changes along the course of the river. The headwater sites were protected by a riparian corridor of native forest, but this was replaced by intensive subsistence agriculture in the mid-reaches while the lower reaches were located within a protected wildlife area with diverse and wide riparian forests. Canonical correspondence analysis indicated that intensive agricultural activities within the mid-reaches caused severe degradation of the stream physical habitat through increased fine sediment deposition. This coincided with a significant decline in macroinvertebrate richness, diversity, and abundance at the agriculturally impacted mid-reach sites. The presence of wide riparian zones at the lower river sites resulted in significant improvements in stream physical habitat quality, and this was paralleled by significant recovery or reappearance of taxa that had disappeared from the mid-reaches. We suggest that restoration of the riparian vegetation within the mid-reaches of the Nyaodza River would lead to improved physical habitat and biotic health of this dry-land river.  相似文献   

20.
北京雾灵山自然保护区冬季鸟类物种多样性调查   总被引:10,自引:2,他引:8  
采用固定调查样线法连续两年对北京雾灵山自然保护区冬季鸟类组成进行了调查,共记录鸟类7目14科44种,其中29种属于留鸟,5种为冬候鸟,7种旅鸟,3种夏候鸟;优势种以留鸟为主,表现出冬季鸟类群落的特点。古北界和东洋界的种类分别为75%和14%,在分布型上划分为7种类型。出现种类最多的生态环境是村落,鸟类种数为31种,其植被类型是低山砾石、农田林果带。调查种类中有国家一级保护鸟类1种,二级保护鸟类6种,北京市重点保护鸟类6种。通过与邻近地区相关调查比较,表明本区冬季鸟类具有较高的丰富性,并提出了有效保护鸟类多样性的对策。  相似文献   

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