Polychaetes of the mangrove-fouling community at the Colombian Archipelago of San Andres and Old Providence,Western Caribbean

This study records the polychaetes found on the submerged roots of Rhizophora mangl on San Andres and Providence Islands, ColombianCaribbean. Sampling was done in 1998 during the rainy (July) and dry(November) seasons; each season, 17 roots were collected in threedifferent stations with different kinds of human impact, two in San Andresand one in Providence. At the same time temperature, salinity anddissolved oxygen were measured in situ. Aromatic hydrocarbons weremeasured in the laboratory. The polychaetes were removed from the rootsand identified. The available root area for the organisms was alsomeasured.Five genera and 11 species were newly recorded for the ColombianCaribbean. The most abundant families were Terebellidae in Old ProvidenceMc Bean Lagoon, Syllidae in Honda Bay and Nereididae in Hooker Bayon the San Andres Island. Thelepus `setosus' (Terebellidae) and Amblyosyllis sp. (Syllidae) were highly abundant in less polluted samplingstations such as Old Providence Mc Bean Lagoon and Honda Bay. On theother hand, Neanthes `succinea' (Nereididae) were abundant inHooker Bay which was the most polluted station. Salinity seemed to be the mostimportant parameter for the polychaete populations. The populations ofpolychaetes, as a total group, seemed to be related to the root areaavailable on both islands, independent of the season. However, during therainy season, the populations were independent of root area availability,while during the dry season, the populations were dependent on it.     

Modern surface pollen assemblages from the Middle and High Atlas,Morocco: insights into pollen representation and transport

Thirty-three modern surface samples were collected in the environmentally and climatologically contrasting regions of the Middle and High Atlas Mountains, Morocco. Samples representing forest and steppe montane environments (1935–2760 m above sea level) are clustered around study sites at Lake Tislit (High Atlas, semi-arid oro-Mediterranean bioclime) and Lake Sidi Ali and Michliffen (Middle Atlas, sub-humid montane Mediterranean bioclime). Good discrimination between regional pollen spectra is evident, with Middle Atlas samples reflecting higher arboreal cover (Cedrus and evergreen Quercus) and High Atlas samples with high abundances of non-arboreal taxa, including Artemisia and Fabaceae. These four taxa (Cedrus, evergreen Quercus, Artemisia and Fabaceae) are furthermore shown to be reliable indicators of local source vegetation within a 100 m² quadrat, taking into account threshold abundances of 7%, 20%, 4% and 10%, respectively. Deciduous Quercus, Olea and Phillyrea show long-distance pollen dispersal across both regions, contributing to non-trivial arboreal pollen (AP) values of up to 35% (typically 20–30%) in the High Atlas spectra. In the Middle Atlas, AP values of 40 to 50% occur in open sampling locations and > 60% under forest canopy cover. These insights should be taken into account when interpreting ancient pollen spectra from regional lakes and bogs for palaeoenvironmental reconstruction.     

Modern pollen deposition in wetlands of Majuli Island and its implication to decipher palaeoflood episodes in northeast India

The present study is the first attempt from any Indian wetland, where palynological data is assessed to understand the flooding histories of the Sakali and Duboi wetlands in the Majuli River Island, a part of the Indo-Burma hotspot. Palynological analyses of surface soil samples from these wetlands were carried out in order to explore the flooding histories of this island. The presence of extra-local taxa such as Rhododendron, Tsuga and Castanopsis, in the Sakali wetland is strongly suggestive of river water transportation and flooding on the Majuli Island in the recent past. In contrast, dominance of local arboreal taxa and low abundance or absence of extra-local pollen taxa in the Duboi wetland does not indicate flooding. Correspondence analysis (CA) was applied on the present dataset to reveal possible correlations between the surface samples of the wetlands and the major group of palynotaxa. The CA successfully discriminated the samples from the two wetlands and also marked strong correlations between flood indicators extra-local taxa with the samples of the Sakali wetland and local arboreal elements with the Duboi samples. The present result will not only provide a baseline for future palaeovegetation and palaeoclimate reconstructions, but will also help in deciphering palaeoflood episodes from these wetlands.     

A modern pollen rain study from the central Andes region of South America

Aim To provide a greater understanding of the modern pollen rain for the central Andes region of South America, thus laying the groundwork for future pollen studies and the derivation of pollen‐climate transfer functions and response surfaces. Location Peru, Bolivia and Chile. Methods Standard palynological techniques for surface soil sampling and discriminant analysis. Results Statistical analysis of the 40 surface samples revealed four palynologically distinct assemblages: (1) the Yungas on the eastern slopes of the Andes; (2) the puna grasslands of the Altiplano; (3) the Coastal Deserts to the west of the Andes; and (4) the Southern Bolivian Highlands. Main conclusions The Yungas group is characterized by high percentages of Urticaceae/Moraceae pollen and fern spores along with trace amounts of pollen from common zoophilous lowland taxa such as Piperaceae, Bignoniaceae and Malpighiaceae. The puna assemblage of the Altiplano is characterized by the dominance of grass (Poaceae) in combination with moderate frequencies of Asteraceae pollen, which tend to increase slightly towards the southern (drier) locations of the Altiplano. Lower percentages of grass pollen and the greater prevalence of Asteraceae, Solanaceae, and the Chenopodiaceae/Amaranthaceae families define the coastal deserts to the west of the Andes. Samples taken from the Southern Bolivian Highlands are characterized by the dominance of Solanaceae in the area, in combination with the pollen of other xerophytic taxa.     

Phytogeographical data and modern pollen rain of the puna belt in southern Peru (Nevado Coropuna, Western Cordillera)

Aim To improve knowledge of the distribution of species and modern pollen dispersal in the puna vegetation belt (central Andes) for palaeoenvironmental analysis and reconstructions. Location Puna belt, Nevado Coropuna, Western Cordillera, Peru. Methods The vegetation facies and belts of the area were mapped by remote sensing using a March 1998 SPOT4 image. This was complemented by the interpretation of aerial photographs, by field sampling, and by the identification of plants. Data from 1940 to 1994 from the Peruvian meteorological station network were modelled to characterize the relationship between climate and vegetation. Twenty‐four soil‐surface samples were collected in the various vegetation facies identified on the map, and standard palynological techniques were applied to analyse these samples. A principal components analysis was performed on the pollen data set. Results The map shows three bioclimatic belts and seven facies in the puna sensu lato, and identifies the main plants that are characteristic of each bioclimatic area. The pollen results fit the vegetation facies and belts, including the plant species of the distinct facies that are well represented in the pollen assemblages. The mesotropical belt is characterized by the predominance of Asteraceae‐type Ambrosia; the supratropical belt shows significant frequencies of Asteraceae‐type Senecio; the orotropical belt is characterized by high frequencies of Apiaceae and includes Polylepis woodland and peat bogs; and the cryorotropical belt shows significant frequencies of Asteraceae‐type Senecio and Apiaceae. Main conclusions The pollen grains of the plants that grow on the puna sensu lato are generally entomophilous and are therefore not transported far from their plant source. The distinct bioclimatic facies and belts identified by the cartography can thus be well distinguished by their pollen production and deposition. We were therefore able to characterize the relationship between pollen, vegetation and climate that can be used for palaeoenvironmental reconstructions. An altitudinal pollen gradient on the western slopes of the central Andes was revealed by the pollen study, with the succession of Asteraceae‐type Ambrosia (1800–2200 m), Malvaceae (2700–3300 m), Asteraceae‐type Senecio (3500–4100 m) and Apiaceae (above 4600 m).     

滇南红河地区现代花粉雨特征及其与气候因子的关系

我国低纬度热带亚热带地区现代花粉雨与气候关系的研究相对缺乏。本研究以滇南红河地区43个水体(湖泊、水库和池塘)的表层沉积物为对象,探讨研究区现代花粉雨与气候因子之间的关系。花粉分析结果表明,木本植物花粉含量高,占优势的是松属、桤木属和壳斗科;次为草本植物,主要为禾本科、菊科和莎草科;花粉谱中蕨类孢子以三缝孢为主,藻类的盘星藻也常见。同时,通过红河地区13个气象观测站1961—2010年月观测数据的线性插值,获得了各水体的现代气候数据(温度包括1月均温、7月均温、春、夏、秋、冬季均温,以及雨季、旱季和年均温;降水包括春、夏、秋和冬季降水量,雨季、旱季和年降水量),并对现代花粉和气候数据进行冗余分析,以揭示影响研究区现代花粉雨的气候因子。冗余分析结果表明,春季、旱季和年降水量及7月、雨季和年均温是控制滇南红河地区现代花粉雨的主要气候因子,温度的增加导致常绿阔叶林占优势,降水减少导致松林占主导。本研究结果能够为滇南红河地区利用化石花粉记录的古气候定量重建提供重要的理论支持。     

Modern pollen–vegetation relationships along transects on the Whangapoua Estuary, Great Barrier Island, northern New Zealand

Aims To quantify pollen–vegetation relationships from saline to freshwater in an estuarine gradient from surface samples of the modern pollen rain, to allow more accurate interpretations of the stratigraphic palynological record. Location Whangapoua Estuary, Great Barrier Island, northern New Zealand. Methods Six transects were laid out along a vegetation sequence running from estuarine mud to freshwater swamp. Along these transect lines, 108 plots were sampled for vegetation and surface sediments from wet sand, mud, plant litter or moss (sand and mud sites are inundated by most tides, other sites less frequently). All sediment samples were analysed for pollen. The relationships between plant species frequency and pollen representation were examined at a community scale using twinspan and ordination analyses, and for individual species using fidelity and dispersibility indices, regression and box‐plot analyses. Results The quantitative relationships between source taxon vegetation frequency and its pollen representation varied between species due to differential pollen production and dispersal. twinspan of the surface pollen samples suggests five vegetation types: (A) mangrove (Avicennia marina); (C) Leptocarpus similis salt meadow; (D) Baumea sedges; (E) Leptospermum shrubland; and (F) Typha/Cordyline swamp forest. The (B) Juncus kraussii community is not represented palynologically owing to the destruction of its delicate pollen grains during acetolysis of samples. Detrended correspondence analysis places these communities on an estuarine‐to‐freshwater gradient. However, pollen assemblages at the seaward end of the salinity gradient are less clearly representative of the associated vegetation than those at the landward end, probably because the open vegetation at the former allows the influx of wind‐ and water‐dispersed pollen from surrounding vegetation. Main conclusions The vegetation pattern (zonation) at Whangapoua is reflected in the pollen rain. When the long‐distance and over‐represented pollen types are excluded, five out of six of the broad vegetation communities can be identified by their pollen spectra. Species with high fidelity and low‐to‐moderate dispersibility indices can be used to identify the vegetation types in the sedimentary sequences. The more open vegetation types at the ‘marine end’ of the sequence tend to be ‘overwhelmed’ by regional pollen, but the nature of the sediments and the presence of discriminatory species (e.g. A. marina, Plagianthus divaricatus, Cordyline australis), even in small amounts, will allow correct identification of the local vegetation represented in sedimentary palynological sequences. A box‐plot analysis indicates that the pollen and spore types A. marina (mangroves), Sarcocornia quinqueflora (salt meadow), P. divaricatus (sedges), Gleichenia (shrubland) and C. australis (swamp forest) are highly discriminatory in relation to vegetation type. These discriminatory palynomorphs help with the interpretation of stratigraphic pollen studies. However, salt marsh vegetation communities in the sediments must be interpreted with caution as the marine sediments are easily affected by erosion, bioturbation and tidal inundation effects.     

A method to forecast the start of theBetula, Platanus andQuercus pollen seasons in North London

This paper attempts the prediction of the start of theBetula, Quercus andPlatanus pollen seasons in London, UK based on pollen sampling conducted over a 5-year period, 1987–1991. The times at which eight different thresholds of accumulated daily pollen counts (M⁻³) were passed were correlated against heat sums, chill units, accumulated sunshine hours, monthly meteorological parameters and the start dates of earlier pollen seasons to identify significant associations. Few meteorological parameters were significantly correlated with the start dates of the three pollen seasons, the exceptions being significant negative correlations between the average monthly air temperature in the months immediately preceding theBetula andPlatanus pollen season. However, significant relationships were identified between the start dates of theBetula, Quercus andPlatanus pollen seasons and the start of theCorylus, Taxus andPopulus pollen seasons with coefficients of determination as high as 98%. These indicator species were then used as predictors to forecast the start of theBetula, Quercus andPlatanus pollen seasons, both individually and in combination with one another, providing levels of explanation of up to 99%.     

A 7000-year pollen record from the Amazon lowlands,Ecuador

The longest continuous Amazonian palynological record (ca 7010 yrs B.P. to present) from Lake Ayauchⁱ, Ecuador, reveals species-by-species abundance changes during a period of climatic change. Pollen influx from a wet tropical rain forest was found to be high, 1×10⁴–10⁵ grains cm^-2 yr^-1, although mature forest taxa were poorly represented. Horizons of laminated sediments and weathered gyttja, dated to ca 4200–3150 B.P., evidence a period of reduced net water availability. During this period Ficus, Alchornea and Palmae pollen representation appears to decline, although there is no evidence of a major forest compositional change. The lake was reduced to a shallow, possibly seasonal, pool. Zea cultivation was recorded between ca 2850 B.P., (the earliest paleoecological record to date in the Amazon basin) and ca 800 B.P. It is suggested that Zea was cultivated on exposed lake sediment within the crater at times of low water levels. The abandonment of Zea cultivation may have been due to rising water levels or social unrest.     

Modern pollen samples from alpine vegetation on the Tibetan Plateau

• 1 A set of 316 modern surface pollen samples, sampling all the alpine vegetation types that occur on the Tibetan Plateau, has been compiled and analysed. Between 82 and 92% of the pollen present in these samples is derived from only 28 major taxa. These 28 taxa include examples of both tree (AP) and herb (NAP) pollen types.
• 2 Most of the modern surface pollen samples accurately reflect the composition of the modern vegetation in the sampling region. However, airborne dust‐trap pollen samples do not provide a reliable assessment of the modern vegetation. Dust‐trap samples contain much higher percentages of tree pollen than non‐dust‐trap samples, and many of the taxa present are exotic. In the extremely windy environments of the Tibetan Plateau, contamination of dust‐trap samples by long‐distance transport of exotic pollen is a serious problem.
• 3 The most characteristic vegetation types present on the Tibetan Plateau are alpine meadows, steppe and desert. Non‐arboreal pollen (NAP) therefore dominates the pollen samples in most regions. Percentages of arboreal pollen (AP) are high in samples from the southern and eastern Tibetan Plateau, where alpine forests are an important component of the vegetation. The relative importance of forest and non‐forest vegetation across the Plateau clearly follows climatic gradients: forests occur on the southern and eastern margins of the Plateau, supported by the penetration of moisture‐bearing airmasses associated with the Indian and Pacific summer monsoons; open, treeless vegetation is dominant in the interior and northern margins of the Plateau, far from these moisture sources.
• 4 The different types of non‐forest vegetation are characterized by different modern pollen assemblages. Thus, alpine deserts are characterized by high percentages of Chenopodiaceae and Artemisia, with Ephedra and Nitraria. Alpine meadows are characterized by high percentages of Cyperaceae and Artemisia, with Ranunculaceae and Polygonaceae. Alpine steppe is characterized by high abundances of Artemisia, with Compositae, Cruciferae and Chenopodiaceae. Although Artemisia is a common component of all non‐forest vegetation types on the Tibetan Plateau, the presence of other taxa makes it possible to discriminate between the different vegetation types.
• 5 The good agreement between modern vegetation and modern surface pollen samples across the Tibetan Plateau provides a measure of the reliability of using pollen data to reconstruct past vegetation patterns in non‐forested areas.

     

Contribution of Dead Wood to Biomass and Carbon Stocks in the Caribbean: St. John, U.S. Virgin Islands

Dead wood is a substantial carbon stock in terrestrial forest ecosystems and hence a critical component of global carbon cycles. Given the limited amounts of dead wood biomass and carbon stock information for Caribbean forests, our objectives were to: (1) describe the relative contribution of down woody materials (DWM) to carbon stocks on the island of St. John; (2) compare these contributions among differing stand characteristics in subtropical moist and dry forests; and (3) compare down woody material carbon stocks on St. John to those observed in other tropical and temperate forests. Our results indicate that dead wood and litter comprise an average of 20 percent of total carbon stocks on St. John in both moist and dry forest life zones. Island-wide, dead wood biomass on the ground ranged from 4.55 to 28.11 Mg/ha. Coarse woody material biomass and carbon content were higher in moist forests than in dry forests. No other down woody material components differed between life zones or among vegetation categories ( P > 0.05). Live tree density was positively correlated with fine woody material and litter in the moist forest life zone ( R = 0.57 and 0.84, respectively) and snag basal area was positively correlated with total down woody material amounts ( R = 0.50) in dry forest. Our study indicates that DWM are important contributors to the total biomass and, therefore, carbon budgets in subtropical systems, and that contributions of DWM on St. John appear to be comparable to values given for similar dry forest systems.     

Nutrient cycling in a tropical seasonal rain forest of Xishuangbanna, Southwest China. Part 1: tree species: nutrient distribution and uptake

Tropical rain forests are characterized by large numbers of the species with diverse growth habits. The objective of the present study was to determine the distribution of nutrient content in the major trees of the tropical rain forests in Xishuangbanna. This will improve the understanding of the nutrient losses from such sites that result from harvesting and flow of nutrients within the ecosystem and lead to the development of effective and rational forest management strategies. Based on the results in this study, the distribution of nutrients among biomass components of trees varied: The ordering of major elements concentrations was K>N>Mg>Ca>P in branch, stem and root tissues but was N>K>Mg>Ca>P in leaves. The maximum amount of all nutrients per ha occurred in the stems followed by branches, roots and leaves. Of the total uptake of 6167.7 kg ha⁻¹ of all nutrients, the contribution of various nutrients was found to be N (2010.6 t ha⁻¹), P (196.3 t ha⁻¹), K (2123.8 kg ha⁻¹), Ca (832 kg ha⁻¹) and Mg (1005 kg ha⁻¹). However, comparing the nutrient uptake of other tropical and sub tropical forests, the results indicated that rates for the Xishuangbanna forests were 20–35% lower than previously reported values.     

Island biogeography and landscape ecology of mammals inhabiting fragmented, temperate rain forests

• 1 We expanded the island biogeography paradigm to test whether mammalian communities of the heavily fragmented temperate rain forests of the Olympic Peninsula were influenced by local environmental conditions, biogeographic factors (fragment area and isolation) and characteristics of the surrounding landscape.
  • 2 We used live‐trapping, sign surveys and infra‐red triggered cameras to compare distributions of non‐volant mammals among fragments and between fragments and other principal landscape components (continuous old‐growth, riparian corridors, second‐growth forest and clearcuts).
    • 3 Of the 24 species of non‐volant mammals detected during our studies, 18 occurred in at least one fragment.
      • 4 Species richness of old‐growth mammals was not significantly correlated with fragment area or isolation, per se, but was significantly and positively correlated with the amount of old‐growth fragments and old second‐growth (41–159 years) in the surrounding landscape (r² = 0.95, P < 0.005).
        • 5 Distributions of three old‐growth dependent species [shrew‐mole (Neurotrichus gibbsii), Douglas squirrel (Tamiasciurus douglasii) and Trowbridge shew (Sorex trowbridgii)] were significantly associated with local environmental conditions within the fragment, with geographical isolation from continuous old‐growth and riparian corridors, and with the amount of old‐growth and old second growth in the adjacent matrix.

     

Vegetation reconstruction on the basis of pollen in Late Pleistocene hyena coprolites from San Teodoro Cave (Sicily, Italy)

Vegetation reconstruction based on pollen from coprolites of extinct spotted hyena (Crocuta crocuta spelaea, Goldfuss 1832) recovered from excavations carried out in 1998 at San Teodoro Cave (Sicily, Italy) supports previous indications of pre-Late Glacial conditions. Eight of the twelve coprolites analysed contained well-preserved pollen grains. There is a general similarity between the pollen contents from the coprolites but they show variability. They suggest a main vegetation type dominated by steppic taxa (Poaceae, Artemisia, Ephedra, Chenopodiaceae and Asteraceae) but also including arboreal taxa (Pinus and Cupressaceae). Low percentages of pollen of mesophilous woody taxa (Quercus, Betula, Abies, Alnus, Pistacia, among others) are noticeable, suggesting the existence of nearby refugia for temperate and Mediterranean vegetation. A reconstruction of the landscape, using the coprolite pollen record and other pollen records from Sicily and south Italy, shows the predominance, during the pre-Late Glacial, of a wooded steppe biome, with elements representing a variety of local environmental conditions.     

海南岛霸王岭热带低地雨林树木的空间格局

树木空间格局及其形成过程是物种共存及生物多样性维持机制研究的一个重要方面。该文以海南岛两个1 hm ²的典型热带低地雨林老龄林森林动态样地为基础, 通过4个点格局模型(均质Poisson过程、异质Poisson过程、均质Thomas过程和异质Thomas过程)模拟扩散限制和生境异质性作用对树木空间分布格局的影响, 并分析不同空间尺度下(< 2 m, 2-5 m, 5-10 m, 10-15 m, 15-20 m和20-25 m)不同作用的相对重要性。结果表明: 热带低地雨林的所有树木总体上呈现聚集分布的空间格局, 随着尺度的增大, 聚集强度逐渐减小。树种在模拟空间分布格局最优模型中的比例由高到低分别是: 均质Thomas过程, 均质Poisson过程、异质Thomas过程和异质Poisson过程。扩散限制作用是形成热带低地雨林树木空间分布格局最重要的生态过程, 其次是完全随机作用以及生境异质性和扩散限制的联合作用, 而生境异质性的作用最小。不同空间尺度上模拟各树种空间分布格局的最优模型比例差异显著, 扩散限制作用能够在多数空间尺度上模拟多个树种的空间分布格局, 其次为随机作用; 生境异质性和扩散限制的联合作用主要在小尺度(0-5 m)影响树种分布, 而生境异质性在较大尺度(15-25 m)上影响树种的空间分布格局。     

Scale-dependent spatial patterns of species diversity in the tropical montane rain forest in Jianfengling,Hainan Island,China

Aims Spatial distribution patterns and formation mechanisms of species diversity are fundamental issues in community ecology. The objectives of this study are to assess the species diversity patterns at the different spatial scales in Jianfengling, Hainan Island, China.
Methods Based on the dataset from the 60 hm² plot in the tropical montane rain forest in Jianfengling, Hainan Island, the spatial distribution patterns of species richness, species abundance, Shannon-Wiener, Simpson and Pielou’s evenness indices were analyzed at six spatial scales, including 5 m × 5 m, 10 m × 10 m, 20 m × 20 m, 40 m × 40 m, 100 m × 100 m, and 200 m × 200 m, respectively.Important findings
Results showed that spatial distribution patterns of species richness, species abundance and Shannon-Wiener index were much more obviously changed with the spatial scales than Simpson and Pielou’s evenness indices. Change of variance of the species richness with the increase of spatial scales was unimodal, which had the maximum value at the 20 m × 20 m scale. Variance of the species abundance showed a linear relationship with the increase of spatial scales. The positive relationship between species richness and abundance gradually decreased and even disappeared with the increase of sampling scales, which may be correlated with the increase of habitat heterogeneity. The effects of spatial scales on Shannon-Wiener, Simpson, and Pielou’s evenness indices may be also correlated with the composition of rare species in the plot.