Breeding birds associated with seasonal pools in the northeastern United States

ABSTRACT Seasonal pools in the northeastern United States provide habitat for amphibians and invertebrates, but little is known about their importance as habitat for birds. We examined avian community composition at seasonal pools in Rhode Island to test the hypothesis that seasonal pools would support a greater abundance and diversity of birds than nearby upland sites. From mid‐May to June 2008, we conducted point counts at 33 paired sets of seasonal pools and upland sites that were 150 m apart. Bird abundance and diversity was significantly higher at seasonal pools than upland sites, whereas community composition as measured by evenness was similar. We also found that the mean abundance of birds was significantly greater at urban pools than rural pools. Our results suggest that birds preferentially use seasonal pools, particularly in more urban settings, adding to the body of evidence that supports the protection and restoration of small isolated wetlands in urban landscapes.     

Gap-scale disturbance processes in secondary hardwood stands on the Cumberland Plateau,Tennessee, USA

Disturbance regimes in many temperate, old growth forests are characterized by gap-scale events. However, prior to a complex stage of development, canopy gaps may still serve as mechanisms for canopy tree replacement and stand structural changes associated with older forests. We investigated 40 canopy gaps in secondary hardwood stands on the Cumberland Plateau in Tennessee to analyze gap-scale disturbance processes in developing forests. Gap origin, age, land fraction, size, shape, orientation, and gap maker characteristics were documented to investigate gap formation mechanisms and physical gap attributes. We also quantified density and diversity within gaps, gap closure, and gap-phase replacement to examine the influence of localized disturbances on forest development. The majority of canopy gaps were single-treefall events caused by uprooted or snapped stems. The fraction of the forest in canopy gaps was within the range reported from old growth remnants throughout the region. However, gap size was smaller in the developing stands, indicating that secondary forests contain a higher density of smaller gaps. The majority of canopy gaps were projected to close by lateral crown expansion rather than height growth of subcanopy individuals. However, canopy gaps still provided a means for understory trees to recruit to larger size classes. This process may allow overtopped trees to reach intermediate positions, and eventually the canopy, after future disturbance events. Over half of the trees located in true gaps with intermediate crown classifications were Acer saccharum, A. rubrum, or Liriodendron tulipifera. Because the gaps were relatively small and close by lateral branch growth of perimeter trees, the most shade-tolerant A. saccharum has the greatest probability of becoming dominant in the canopy under the current disturbance regime. Half of the gap maker trees removed from the canopy were Quercus; however, Acer species are the most probable replacement trees. These data indicate that canopy gaps are important drivers of forest change prior to a complex stage of development. Even in relatively young forests, gaps provide the mechanisms for stands to develop a complex structure, and may be used to explain patterns of shifting species composition in secondary forests of eastern North America.     

Colour-coded sampling: the pan trap colour preferences of oligolectic and nonoligolectic bees associated with a vernal pool plant

1. Pan traps or water traps have been used widely to sample agricultural insect pests, but no formal studies have assessed the utility of these traps as sampling devices for bees. 2. Coloured pan traps, used as flower models, can efficiently and selectively sample an oligolectic bee, Andrena (Hesperandrena) limnanthis, and other bees associated with white-flowered Limnanthes douglasii rosea. 3. Females and males of A. limnanthis unexpectedly exhibit different colour preferences. Females are strongly attracted to white and blue traps, but discriminate against yellow traps. Males prefer white traps over blue and yellow traps. Consequently, blue traps are selective for females only, while white traps are selective for both sexes. 4. Non-A. limnanthis bees were caught in significantly greater numbers in yellow than in blue or white traps. These bees included generalists, as well as specialists that are oligolectic on mostly yellow-flowered species. 5. Colour of traps had a significant effect on the numbers of A. limnanthis females and males, and non-A. limnanthis bees caught in traps. These results indicate that quantitative sampling of bees by pan trap methods can be highly sensitive to trap colour.     

陕西渭河平原地区乌类物种多样性研究

1999年12月－2000年10月,按冬,春,夏,秋四季,在渭河谷地咸阳地区3个阶地上取有代表性的区域作样带调查,记录鸟类种类和数量,分析不同生境鸟类多样性及其变化规律,本次调查共记录到鸟类124种,隶属于15目35科79属,研究表明,该地区的鸟类总体α多样性水平较高,达3．2845,但不同季节各阶地的多样性水平不高,较高的β多样性指数反映了鸟类种类和组成在不同阶地间变化较大,阶地间多样性的差异表明我国渭河平原地区湿地对鸟类多样性有显著的影响,水是限制鸟类分布和栖息的重要因子。     

红外相机技术与其他几种森林鸟类多样性调查方法的比较

为了探讨红外相机技术、网捕法、固定距离样线法和固定半径样点法对森林鸟类多样性调查的有效性和实用性, 我们于2011-2016年, 用这几种方法调查了广东南岭国家级自然保护区和车八岭国家级自然保护区的鸟类多样性。在南岭, 固定距离样线法和固定半径样点法记录鸟类222种, 网捕鸟类43种, 红外相机拍到鸟类47种; 其中1种鸟仅网捕到, 6种鸟仅被红外相机拍到, 164种鸟仅被固定距离样线法和固定半径样点法记录到。在车八岭, 固定距离样线法和固定半径样点法记录鸟类109种, 网捕鸟类42种, 红外相机拍到鸟类27种, 其中9种鸟仅网捕到, 3种鸟仅被红外相机拍到, 97种鸟仅被固定距离样线法和固定半径样点法记录到。随着鸟类的体重、体长、翅长和跗蹠增加, 网捕到的鸟类个体数量减少, 鸟类身体大小与网捕到的鸟类数量呈显著负相关; 而红外相机拍到的鸟类数量随鸟类的身体大小增大而增加, 并且呈显著的正相关。本文的结果显示, 网捕法和红外相机技术针对不同类群的鸟类调查效力不同, 但都是固定距离样线法和固定半径样点法的有效补充。建议今后开展森林鸟类多样性调查与监测时, 尽量采用多种研究方法相结合, 以求达到最优的效果。     

Kleptoparasitic interactions throughout the animal kingdom and a re-evaluation, based on participant mobility, of the conditions promoting the evolution of kleptoparasitism

Understanding of the conditions encouraging the evolution of kleptoparasitism has been limited by the preponderance of attention focused on a limited number of taxa (predominantly birds). However, most animal taxa contain kleptoparasitic members. In many ways, adult birds are aberrant because most are acrobatic, capable of three-dimensional movement, and steal from hosts that are capable of similar feats. The mobility of kleptoparasites and their hosts falls along a continuum, with the acrobatic birds at one end and sessile hosts and kleptoparasites at the other. Considering sedentary systems requires amendments to the criteria previously outlined as necessary for kleptoparasitism. Kleptoparasitic interactions between agile participants are ephemeral, involve numerous hosts over the lifetime of the kleptoparasite, and usually rely on vision. Large concentrations of hosts and large, high-quality food items are important in mobile systems. By contrast, the long-term, intimate associations of sedentary interactions demand that the host not consume the kleptoparasite's offspring and that the host must either have a longer life cycle than the kleptoparasite or be located in aggregations that have staggered life cycles (so the kleptoparasite can move to a new host when the original host dies). Expanding studies of kleptoparasitism to other taxa will differentiate between the selective pressures and evolutionary responses that are universal among kleptoparasitic symbioses and those that are restricted to certain groups.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 745–762.     

氮添加对黄土丘陵区油松人工林根际土壤微生物群落结构的影响

中国南方及中部为高氮沉降区(～35 kg·hm^-2·a^-1),氮沉降量向西北依次递减(～7.55 kg·hm^-2·a^-1).黄土高原区历经几十年的退耕还林还草而面貌一新,但该区域人工林土壤微生物群落结构对氮素添加响应的研究还鲜有报道.本研究以黄土丘陵区不同林龄油松人工林为研究对象,应用Illumina HiSeq测序技术对细菌16S rDNA和真菌ITS进行序列测定与分析,探讨根际土壤细菌和真菌群落结构组成对土壤氮添加(施用量为200 kg N·hm^-2·a^-1纯氮)的响应,旨在探究我国西北黄土丘陵区油松人工林根际土壤微生物多样性及群落结构对定量氮添加的响应.结果表明: 氮添加显著增加了25年龄林地细菌和真菌Shannon多样性,显著增加了40年龄林地细菌丰度指数.氮添加显著增加了40年龄林地拟杆菌门的相对丰度和25年龄林地酸杆菌门及接合菌门的相对丰度,但显著降低了40年龄林地奇古菌门的相对丰度.非度量多维尺度分析结果显示,氮添加对土壤细菌群落结构组成的影响程度大于真菌,对25年龄林地微生物群落结构组成的影响程度大于40年龄林地.表明不同林龄油松人工林根际土壤微生物的多样性及群落结构对土壤氮添加响应具有差异性.相对于真菌群落结构组成,细菌群落结构组成对氮添加更敏感;相对于40年龄林地,25年龄林地根际土壤微生物的群落结构组成对氮添加更敏感.因此,黄土高原区人工林地生态系统演替到一定阶段(40年左右),比幼龄林地生态系统更能承受外界较大的氮添加扰动.     

The effects of whole-tree clear-cutting on soil processes at the Hubbard Brook Experimental Forest,New Hampshire,USA

The effects of whole-tree clear-cutting on soil processes and streamwater chemistry were examined in a northern hardwood forest at the Hubbard Brook Experimental Forest, New Hampshire. Soil processes were examined by monitoring soil solution chemistry collected using zero-tension lysimeters from the Oa, Bh and Bs horizons at three sites along an elevational/vegetation gradient. Whole-tree clear-cutting created a severe ecosystem disturbance leading to leaching losses of nutrients from the soil profile, increased acidification, and elevated concentrations of Al-ions in soil solutions and streamwater. The response was driven by the process of nitrification that led to production of nitric acid in both the forest floor and mineral soil horizons. This acidity was largely neutralized by release and leaching of basic cations and inorganic monomeric Al-ions leaching with the NO₃-ions. The major source of nutrient loss was from the forest floor. The chemical response to the clear-cut was most intense during the second year following the treatment and declined to near reference concentrations in 4–5 years. High elevation sites showed the greatest response to disturbance and the slowest recovery of soil solution concentrations to pre-cut concentrations. Shallow soils and a slower recovery of vegetation at the upper elevation sites were the primary factors contributing to the enhanced disturbance and delayed recovery (and enhanced response to disturbance in the upper elevation sites).     

Influence of Tree Species on Forest Nitrogen Retention in the Catskill Mountains, New York, USA

This study examines the effect of four tree species on nitrogen (N) retention within forested catchments of the Catskill Mountains, New York (NY). We conducted a 300-day ¹⁵N field tracer experiment to determine how N moves through soil, microbial, and plant pools under different tree species and fertilization regimes. Samples were collected from single-species plots of American beech (Fagus grandifolia Ehrh.), eastern hemlock (Tsuga canadensis L.), red oak (Quercus rubra L.), and sugar maple (Acer saccharum Marsh). Using paired plots we compared the effects of ambient levels of N inputs (11 kg N/ha/y) to additions of 50 kg N/ha/y that began 1.5 years prior to and continued throughout this experiment. Total plot ¹⁵N recovery (litter layer, organic and mineral soil to 12 cm, fine roots, and aboveground biomass) did not vary significantly among tree species, but the distribution of sinks for ¹⁵N within the forest ecosystem did vary. Recovery in the forest floor was significantly lower in sugar maple stands compared to the other species. ¹⁵Nitrogen recovery was 22% lower in the fertilized plots compared to the ambient plots and red oak stands had the largest drop in ¹⁵N recovery as a result of N fertilization. Aboveground biomass became a significantly greater ¹⁵N sink with fertilization, although it retained less than 1% of the tracer addition. These results indicate that different forest types vary in the amount of N retention in the forest floor, and that forest N retention may change depending upon N inputs.     

Vertical distribution of earwigs (Dermaptera: Forficulidae) in a temperate lowland forest,based on sampling with a mobile aerial lift platform

Although earwigs (Dermaptera) may be important components of ecosystems because of their locally high abundance and omnivory, their vertical distribution among forest strata is poorly understood. This study used a mobile aerial lift platform to survey the spatiotemporal distribution of earwigs along the vertical dimension in a forest. In 2013 and 2014, 57 trees in a lowland floodplain forest were sampled in the southeastern Czech Republic, Central Europe. Earwigs were collected along the complete vertical gradient of the foliage of the trees using square beating sheets and exhaustors. Of the three recorded earwig species (Apterygida media, Chelidura acanthopygia and Forficula auricularia), A. media was the most abundant. The distribution of its abundance with the height from ground (in the tree leaf layer) was unimodal, with a peak at 4–10 m, indicating that A. media is arboricolous. The vertical stratification of A. media differed among developmental stages, and in its abundance among tree species. Investigation of insect vertical stratification in forests should be facilitated by the use of a mobile aerial lift platform.     

Effects of a clearcut on the net rates of nitrification and N mineralization in a northern hardwood forest,Catskill Mountains,New York,USA

The Catskill Mountains of southeastern New York receive among the highest rates of atmospheric nitrogen (N) deposition in eastern North America, and ecosystems in the region may be sensitive to human disturbances that affect the N cycle. We studied the effects of a clearcut in a northern hardwood forest within a 24-ha Catskill watershed on the net rates of N mineralization and nitrification in soil plots during 6 years (1994–1999) that encompassed 3-year pre- and post-harvesting periods. Despite stream NO₃^– concentrations that increased by more than 1400 mol l^–1 within 5 months after the clearcut, and three measures of NO₃^– availability in soil that increased 6- to 8-fold during the 1^st year after harvest, the net rates of N mineralization and nitrification as measured by in situ incubation in the soil remained unchanged. The net N-mineralization rate in O-horizon soil was 1– 2 mg N kg^–1 day^–1 and the net nitrification rate was about 1 mg N kg^–1 day^–1, and rates in B-horizon soil were only one-fifth to one-tenth those of the O-horizon. These rates were obtained in single 625 m² plots in the clearcut watershed and reference area, and were confirmed by rate measurements at 6 plots in 1999 that showed little difference in N-mineralization and nitrification rates between the treatment and reference areas. Soil temperature increased 1 ± 0.8 °C in a clearcut study plot relative to a reference plot during the post-harvest period, and soil moisture in the clearcut plot was indistinguishable from that in the reference plot. These results are contrary to the initial hypothesis that the clearcut would cause net rates of these N-cycling processes to increase sharply. The in situ incubation method used in this study isolated the samples from ambient roots and thereby prevented plant N uptake; therefore, the increases in stream NO₃^– concentrations and export following harvest largely reflect diminished uptake. Changes in temperature and moisture after the clearcut were insufficient to measurably affect the net rates of N mineralization and nitrification in the absence of plant uptake. Soil acidification resulting from the harvest may have acted in part to inhibit the rates of these processes. The US Governments right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged.     

Effects of the emerald ash borer invasion on the community composition of arthropods associated with ash tree boles in Maryland,U.S.A.

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青藏高原东南部森林群落生态位特征与物种多样性的影响因素

青藏高原东南部的东喜马拉雅地区和横断山区是全球生物多样性热点区,也是青藏高原重要的生态安全屏障区,但对该区域森林群落的生态位特征以及多样性相关研究较少。收集和整理了分布于青藏高原东南部的乔木植物及其科属特征,并分析主要优势物种的生态位特征以及森林群落多样性的影响因素。采用"Levins"方法计算优势物种的生态位宽度和生态位重叠值;随后,使用方差比率法、 χ²检验、Association coefficient联结系数和Ochiai指数等方法分析了种间联结性;最后,使用方差分解方法计算了每个环境因素对植物多样性的解释率。研究结果表明:(1)位于东喜马拉雅地区和横断山区森林群落共有植物42科71属119种,物种组成主要以松科(17种)、杜鹃花科(10种)、桦木科(9种)、无患子科(8种)和樟科(6种)为主;(2)该地区所有种植物生态位重叠值较低(平均值为0.027),并且生态位重叠值为0的种对数最多,说明森林群落整体竞争较小,处于一个相对稳定的状态;(3)生态位宽度值由高到低的物种依次为:冷杉、杜鹃、云南铁杉、川西云杉、落叶松、黄背栎、高山栎、花楸、石栎和云南松,这10种植物在森林群落占据优势地位;(4)种间关联结果显示方差比率大于1,说明森林群落中物种间存在较强的正关联,群落内各个物种占据的不同生态位,合理地利用各种资源;(5)年均温和坡向被认为是影响该地区森林群落物种多样性最关键的两个环境因子;(6)森林群落在年均温为7-11℃的地区和半阳坡的地形中,群落植物多样性最高。     

黄土高原子午岭森林群落演替与结构特征演化

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基于物种落差分析的公园鸟类多样性提升设计——以湖南常德螺湾湿地公园为例

随着城市化发展,许多公园鸟类栖息环境遭受破坏,导致当前的鸟类多样性与历史上的和周边的都存在较大差异,为此,我们从项目区域的当前-周边-历史三者间在鸟类物种及其栖息地上的落差分析入手,以此确定目标物种及其栖息地,并加以归类,从而有针对性地进行相关设计。2016年5月至2017年3月在湖南常德柳叶湖螺湾湿地公园开展的鸟类多样性提升设计中,通过实地调查并结合文献查阅,记录到项目区域16种,周边79种,历史上146种鸟类,运用三者间的物种落差分析法确定主要的21种可恢复目标物种和4种栖息地类型,结合项目区域及周边空间特点,将项目区域划分为4个区域,在各区域内设计并营建相应的栖息地,再配套采用多种鸟类招引措施。至2017年3月,项目区鸟类已可实地观察到39种,并于2017年12月吸引到超过2000只的野鸭群来此越冬。以上实际效果表明,设计有效地提升了湿地公园鸟类多样性且增加了景观要素,可充分发挥生物保护功能。     

Experimental assessment of salamanders as predators of detrital food webs: effects on invertebrates, decomposition and the carbon cycle

Declines in amphibian populations and the loss of some species has spurred research into the causes of declines. Little research has been done on what the loss of amphibian species may mean to ecosystem function. I describe a field experiment where the number of Plethodon cinereus (the red-backed salamander) was manipulated in enclosures buried in the forest floor. I determined the composition of the forest floor invertebrate community and the rate of decomposition of leaf litter in enclosures with and without salamanders over 4.5 months. Salamander predation in enclosures significantly reduced invertebrate numbers compared to control enclosures. Salamander predation also indirectly reduced rate of decomposition by between 11 and 17%. This was probably due to salamanders consuming a significant number of leaf fragmenters (e.g. Coleoptera and Diptera larvae). Predation on leaf litter fragmenters may alter carbon dynamics in forested ecosystems.     

Distribution and characteristics of <Emphasis Type="Italic">Bacillus</Emphasis> bacteria associated with hydrobionts and the waters of the Peter the Great Bay,Sea of Japan

Bacilli of the species Bacillus subtilis, B. pumilus, B. mycoides, B. marinus and B. licheniformis (a total of 53 strains) were isolated from 15 invertebrate species and the water of the Vostok Bay, Peter the Great Bay, Sea of Japan. Bacilli were most often isolated from bivalves (22.7%) and sea cucumbers (18.9%); they occurred less frequently in sea urchins and starfish (13.2 and 7.5%, respectively). Most of bacilli strains were isolated from invertebrates inhabiting silted sediments. No Bacillus spp. strains were isolated from invertebrates inhabiting stony and sandy environments. The species diversity of bacilli isolated from marine objects under study was low. Almost all bacterial isolates were resistant to lincomycin. Unlike B. pumilus, B. subtilis isolates were mostly resistant to benzylpenicillin and ampicillin. Antibiotic sensitivity of B. licheniformis strains was variable (two strains were resistant to benzylpenicillin and oxacillin, while one was sensitive). A significant fraction of isolated bacilli contained pigments. Pigmented strains were more often isolated from seawater samples, while colorless ones predominated within hydrobionts. B. subtilis colonies had the broadest range of colors. In the Bacillus strains obtained, DNase, RNase, phosphatase, elastolytic, chitinase, and agarolytic activity was detected. Bacilli strains with hydrolytic activity occurred in invertebrates more often than in seawater.     

A study on the diversity of the moth community in the North Dagang Wetland Nature Reserve, Tianjin, China

North Dagang Wetland Nature Reserve is situated in the southeast of Tianjin, China. It is the biggest wetland nature reserve in Tianjin. An investigation into the diversity of the moth community was carried out from June 12 to October 14, 2001, and then from April 12 to October 30, 2002. The investigation was conducted in order to identify the moth species in wetlands, study their dynamic laws, select indicator insects to indicate wetland quality, and assist in the study and protection of wetlands. A total of 132 moth species were collected, which belonged to 105 genera in 17 families. The data about insects which was collected during the survey was listed and constructed in terms of species-abundance, indices of diversity (H′), evenness (J′), specific richness (S) and individual number (N) using the Microsoft Excel Program. The status of the wetlands was also analyzed using the moth community species-abundance curve, indices of diversity, the connection between evenness and richness indices, etc. The results show that moth species in the wetlands were not rich, and the moth community was unstable. In other words, the living environment of the moths and the environmental quality of the wetlands were unstable due to the serious degeneration of the wetland environment and human activities.     

A study on the diversity of the moth community in the North Dagang Wetland Nature Reserve, Tianjin, China

North Dagang Wetland Nature Reserve is situated in the southeast of Tianjin, China. It is the biggest wetland nature reserve in Tianjin. An investigation into the diversity of the moth community was carried out from June 12 to October 14, 2001, and then from April 12 to October 30, 2002. The investigation was conducted in order to identify the moth species in wetlands, study their dynamic laws, select indicator insects to indicate wetland quality, and assist in the study and protection of wetlands. A total of 132 moth species were collected, which belonged to 105 genera in 17 families. The data about insects which was collected during the survey was listed and constructed in terms of species-abundance, indices of diversity (H′), evenness (J′), specific richness (S) and individual number (N) using the Microsoft Excel Program. The status of the wetlands was also analyzed using the moth community species-abundance curve, indices of diversity, the connection between evenness and richness indices, etc. The results show that moth species in the wetlands were not rich, and the moth community was unstable. In other words, the living environment of the moths and the environmental quality of the wetlands were unstable due to the serious degeneration of the wetland environment and human activities.