Plant Ecology

A central goal of comparative plant ecology is to understand how functional traits vary among species and to what extent this variation has adaptive value. Here we evaluate relationships between four functional traits (seed volume, specific leaf area, wood density, and adult stature) and two demographic attributes (diameter growth and tree mortality) for large trees of 240 tree species from five Neotropical forests. We evaluate how these key functional traits are related to survival and growth and whether similar relationships between traits and demography hold across different tropical forests. There was a tendency for a trade-off between growth and survival across rain forest tree species. Wood density, seed volume, and adult stature were significant predictors of growth and/or mortality. Both growth and mortality rates declined with an increase in wood density. This is consistent with greater construction costs and greater resistance to stem damage for denser wood. Growth and mortality rates also declined as seed volume increased. This is consistent with an adaptive syndrome in which species tolerant of low resource availability (in this case shade-tolerant species) have large seeds to establish successfully and low inherent growth and mortality rates. Growth increased and mortality decreased with an increase in adult stature, because taller species have a greater access to light and longer life spans. Specific leaf area was, surprisingly, only modestly informative for the performance of large trees and had ambiguous relationships with growth and survival. Single traits accounted for 9-55% of the interspecific variation in growth and mortality rates at individual sites. Significant correlations with demographic rates tended to be similar across forests and for phylogenetically independent contrasts as well as for cross-species analyses that treated each species as an independent observation. In combination, the morphological traits explained 41% of the variation in growth rate and 54% of the variation in mortality rate, with wood density being the best predictor of growth and mortality. Relationships between functional traits and demographic rates were statistically similar across a wide range of Neotropical forests. The consistency of these results strongly suggests that tropical rain forest species face similar trade-offs in different sites and converge on similar sets of solutions.

Wild ungulates are often considered a threat to natural forest regeneration in windthrow areas. We studied their impact on developing vegetation in windthrow clearings on the northern side of the Swiss Alps. Fifty pairs of exclosure and control plots were established seven years after the windthrow and the composition and percentage of vegetation cover recorded. At that time, vegetation cover, including regeneration of woody species, did not differ on the two types of plots. Three years later, total cover had increased by about 40% in both types of plots. Thus, browsing ungulates did not slow down the growth of plant cover. The ungulates had only mild effects on the development of some plant groups: tall forbs, such as Epilobium angustifolium, which ungulates prefer, were fewer in the unfenced control plots than in exclosures, although the frequency of the other favourite species like Vaccinium myrtillus were not influenced by ungulates. The numbers of seedlings and saplings of woody species had increased four-fold on both types of plots by the end of the study. Thus, browsing ungulates affected neither the development nor the survival of woody species. Only Sorbus aucuparia, a species that ungulates prefer, was 30% higher in the exclosures. Other preferred species, such as Acer pseudoplatanus, were not affected by browsing. Although ungulates are able to modify forest ecosystems and may significantly reduce vegetation on forest floors, in the windthrow areas the rapidly increasing plant biomass seemed to exceed their consumption needs and browsing capacity. The ungulates had access to more than ample food and could select the best.Therefore, our results provide no evidence that browsing ungulates threaten the natural regeneration of forest stands in windthrow gaps.

Soil water repellency (SWR) is a widespread challenge to plant establishment and growth. Despite considerable research, it remains a recalcitrant problem for which few alleviation technologies or solutions have been developed. Previous research has focused on SWR as a problem to be overcome, however, it is an inherent feature of many native ecosystems where it contributes to ecosystem functions. Therefore, we propose a shift in the way SWR is perceived in agriculture and in ecological restoration, from a problem to be solved, to an opportunity to be harnessed. A new focus on potential ecological benefits of SWR is particularly timely given increasing incidence, frequency and severity of hotter droughts in many regions of the world. Our new way of conceptualising SWR seeks to understand how SWR can be temporarily alleviated at a micro-scale to successfully establish plants, and then harnessed in the longer term and at larger spatial scales to enhance soil water storage to act as a "drought-proofing" tool for plant survival in water-limited soils. For this to occur, we suggest research focusing on the alignment of physico-chemical and microbial properties and dynamics of SWR and, based on this mechanistic understanding, create products and interventions to improve success of plant establishment in agriculture, restoration and conservation contexts. In this paper, we outline the rationale for a new way of conceptualising SWR, and the research priorities needed to fill critical knowledge gaps in order to harness the ecological benefits from managing SWR.

IntroductionRecent decades have seen a major international effort to inventory tree communities in the Amazon Basin and Guiana Shield (Amazonia), but the vast extent and record diversity of these forests have hampered an understanding of basinwide patterns. To overcome this obstacle, we compiled and standardized species-level data on more than half a million trees in 1170 plots sampling all major lowland forest types to explore patterns of commonness, rarity, and richness.MethodsThe ~6-million-km2Amazonian lowlands were divided into 1° cells, and mean tree density was estimated for each cell by using a loess regression model that included no environmental data but had its basis exclusively in the geographic location of tree plots. A similar model, allied with a bootstrapping exercise to quantify sampling error, was used to generate estimated Amazon-wide abundances of the 4962 valid species in the data set. We estimated the total number of tree species in the Amazon by fitting the me...

A hierarchical approach for plant functional classification was applied to describe long-term vegetation change in Pinus halepensis burned forests. Plant species were initially grouped according to their growth form and afterwards data on species modes of regeneration, persistence and dispersal, together with some other specific competitive advantages were explored, resulting in the identification of 29 different functional groups, 14 for woody and 15 for herbaceous species. Three types of Pinus halepensis forests were identified, according to the structure of the understorey. For each forest type, a post-fire chronosequence of communities was selected for sampling. Data sampling was performed for at least two consecutive years in each community, so as to reduce the shortcomings of the synchronic approach and to increase the age range of each chronosequence. Even though the vast majority of the functional groups proved to be persistent throughout the post-fire development of vegetation, their species richness and abundance did not remain stable. An increase of annual herb richness and abundance was recorded in the first years after the fire, with the leguminous species forming the dominant functional group. For perennial herbs, the most abundant group was of species with vivid lateral growth, while the group of species with subterranean resource organs included the highest number of species. Finally, as far as the woody species are concerned, the groups that played the most important role in defining vegetation structure were the mono-specific group of the pine, the group of resprouting sclerophyllous tall shrubs and the group of obligate seeder short shrubs (with Cistus spp., among others). A negative relationship between the abundance of woody obligate resprouters and the regeneration of woody obligate seeders was found. The advantage of the proposed functional group approach over classical floristic or structural approaches for the long-term study of communities is discussed, together with the applicability of this approach in studies of vegetation risk assessments due to fire regime alterations.

IntroductionRecent decades have seen a major international effort to inventory tree communities in the Amazon Basin and Guiana Shield (Amazonia), but the vast extent and record diversity of these forests have hampered an understanding of basinwide patterns. To overcome this obstacle, we compiled and standardized species-level data on more than half a million trees in 1170 plots sampling all major lowland forest types to explore patterns of commonness, rarity, and richness.MethodsThe ~6-million-km2Amazonian lowlands were divided into 1° cells, and mean tree density was estimated for each cell by using a loess regression model that included no environmental data but had its basis exclusively in the geographic location of tree plots. A similar model, allied with a bootstrapping exercise to quantify sampling error, was used to generate estimated Amazon-wide abundances of the 4962 valid species in the data set. We estimated the total number of tree species in the Amazon by fitting the me...

Management of semi-natural grasslands is essential to retain the characteristic diversity of flora and fauna found in these habitats. To maintain, restore or recreate favourable conditions for grassland species, knowledge regarding how they occur in relation to grazing intensity and soil nutrient availability is crucial. We focused on grassland plant species, i.e., species selected to indicate high natural values in semi-natural grasslands. Environmental monitoring data collected at 366 grassland sites in southern Sweden between 2006 and 2010 were used to relate the occurrence of indicator species to factors describing geographic location, local site conditions related to nutrients and moisture, and management. Site productivity, soil moisture and cover of trees and shrubs were the main structuring factors, while other factors related to management had a lesser effect (grass sward height, amount of litter, type of grazer). Not surprisingly, these patterns were also reflected in spec...

IntroductionRecent decades have seen a major international effort to inventory tree communities in the Amazon Basin and Guiana Shield (Amazonia), but the vast extent and record diversity of these forests have hampered an understanding of basinwide patterns. To overcome this obstacle, we compiled and standardized species-level data on more than half a million trees in 1170 plots sampling all major lowland forest types to explore patterns of commonness, rarity, and richness.MethodsThe ~6-million-km2Amazonian lowlands were divided into 1° cells, and mean tree density was estimated for each cell by using a loess regression model that included no environmental data but had its basis exclusively in the geographic location of tree plots. A similar model, allied with a bootstrapping exercise to quantify sampling error, was used to generate estimated Amazon-wide abundances of the 4962 valid species in the data set. We estimated the total number of tree species in the Amazon by fitting the me...

Evergreen broad-leaved forests (EBLFs, lucidophyllous forests) are vegetation types characteristic of East Asia. The extent of EBLFs has decreased significantly due to long-term anthropogenic disturbance, and remnant EBLFs in urban area are rare and important landscape types contributing to biodiversity and sustainable development. This study focuses on remnant EBLFs on Mt. Gele (GL), Mt. Tieshanping (TSP), and Mt. Jinyun (JY), located from the inner city to outskirts of Chongqing metropolis, Southwest China. Species of Theaceae, Lauraceae, Symplocaceae, and other families, which are essential floristic components of primary EBLFs, were still the main components at the three sites. GL and JY showed higher biodiversity, with richer heliophytes and shade-tolerant species, respectively. Castanopsis carlesii var. spinulosa was the sole dominant species at all three sites in woody layer, with codomination by Pinus massoniana and Cinnamomum camphora at GL and by Machilus pingii and Castanopsis fargesii at JY; these evergreen broad-leaved trees all showed inverse-J or sporadic-shaped size distribution with large numbers of small stems, but the conifer tree Pinus massoniana showed unimodal distribution with small stems at GL. The height growth of tree species, especially Castanopsis carlesii var. spinulosa, was increasingly restricted from JY to TSP to GL. Sprouting is an important life history strategy at community and population level, and differences were exhibited from GL to TSP to JY. A rural-urban gradient from JY to TSP to GL was indicated in this study. Species composition, biodiversity, and stand structure of these remnant EBLFs showed obvious differences along this gradient, and conservation responses to address the effects of urbanization need to be carefully considered.

We investigated temporal and spatial segregation of nectarivores at Agave marmorata inflorescences in Tehuaca ´n, Me ´xico. Using survival analysis, a technique in which data are treated as censored, we found temporal segregation among insects, hummingbirds, and perching birds during the most nectar-limited time. Survivorship curves of hummingbirds and orioles were not significantly different from each other, however, temporal segregation was observed within hummingbirds according to body size and territorial behavior. Temporal segregation among hummingbirds is interpreted as a way to reduce risk of injury. This way hummingbirds meet their short-term energy demands and co-existence may be facilitated in a nectar oasis. In contrast, survivorship curves of oriole species were not statistically different with each other, but spatial segregation is suspected; Scott's Orioles segregate by visiting agaves with taller inflorescences sooner than visiting those with shorter inflorescences. These results along with those of foraging behavior and floral shifts suggest that orioles are the legitimate pollinators of this century plant.

Climate warming has the potential to influence plant flowering phenology which in turn can have broader ecological consequences. Herbarium collections offer a source of historical plant data that makes possible the ability to document and better understand how warming climate can influence long-term shifts in flowering phenology. We examined the influence of annual, winter, and spring temperatures on the flowering phenology of herbarium specimens for 36 species collected from 1884–2015. We then compared the response to warming between native and non-native, woody and herbaceous, dry and fleshy fruit, and spring vs summer blooming species. Across all species, plants flowered 2.26 days earlier per 1 °C increase in annual average temperatures and 2.93 days earlier per 1 °C increase in spring onset average temperatures. Winter temperatures did not significantly influence flowering phenology. The relationship of temperature and flowering phenology was not significantly different between ...

We studied the species composition and soil nutrients in a Pinus brutia forest after a fire that occurred in 1989. Four permanent plots were created in the burnt and not burnt areas in the Amanos Mountains of Turkey. The floristic richness, biological spectra, above ground phytomass and soil features in the study areas were assessed during the first three years after the fire. After the fire, we found a reduced amount of organic matter (14.3%), total nitrogen (22%) and soil water saturation (13.1%), but an increased amount of available phosphorus (71%), acidity (3.6%), cation exchange capacity (9.9%), exchangeable sodium (20.8%) and exchangeable potassium (37.1%). The aboveground phytomass in the burned area reached 5284 kg ha -1 , the third year after the fire. Forty-six pre-fire species were renewed in the first three years after the fire. Juniperus oxycedrus could not renew within three years after the fire. Pine phytomass has increased five times within three years after the fire.

Özet: Güneydoğu Anadolu Bölgesi illerinden biri olan Şanlıurfa'daki zeytin gen kaynaklarının oluşturduğu populasyon içerisinden üstün nitelikli genotipleri seçmek amacıyla gerçekleştirilen bu seleksiyon çalışmasının ilk aşamasında, belirlenen 22 genotipten sürgün, yaprak ve meyve örnekleri alınarak incelenmiştir. Belirlenen genotipler; meyve ağırlığı, 100 g'daki tane sayısı, et/çekirdek oranı, toplam yağ oranı, yağ asitleri kompozisyonu, lentisel büyüklüğü, habitüs, boğumlar arası uzunluk vb. özellikleri dikkate alınarak seçilmiştir. Seçilen 22 genotip Alata Bahçe Kültürleri Araştırma Enstitüsü'nden sağlanan 6 yerli ve 4 yabancı referans çeşitle birlikte, SSR yönteminde 10 mikrosatelit markör (UDO4, UDO9, UDO12, UDO24, UDO26, DCA9, DCA11, DCA13, DCA15, UDO11) kullanılarak, allel profilleriyle genetik tanımlamaları yapılmış, aralarındaki genetik benzerlikler belirlenmiştir. Her bir SSR lokusu için allel büyüklükleri Beckman CEQ 8800 otomatik fragmant analiz sistemi ile belirlenirken, allel sayısı, beklenen ve gözlenen heterozigotluk ve tanımlama olasılığı tespit edilmiş, elde edilen sonuçlar dendogram düzeyinde değerlendirilmiştir.

Studies on the pollination biology of Eriocaulaceae are scarce although particularly interesting because of its inclusion in the Poales, a predominantly wind-pollinated order. The pollination biology of Syngonanthus elegans (Bong.) Ruhland was studied during two annual flowering periods to test the hypothesis that insect pollination was its primary pollination system. A field study was carried out, including observations of the morphology and biology of the flowers, insect visits and pollinator behaviour. We also evaluated seed set, seed germination and seedling development for different pollination modes. Although seeds were produced by self-pollination, pollination by small insects contributed most effectively to the reproductive success of S. elegans, resulting in the greatest seed set, with the highest germination percentage and optimum seedling vigour. The floral resources used by flower visitors were pollen and nectar that was produced by staminate and pistillate flowers. Self...

This paper is part of a wider study in which different combinations of species were assayed for the revegetation of experimentally burnt heathlands. In this particular case, we determined whether there was any interaction between the dominant species, Erica australis, which recovered by vegetative resprouting, and the only successful woody species sown, Cytisus sp., eight years after fire and seven years after sowing. A detailed study was carried out on each square metre of cover and height of both species in three 160 m 2 plots. Total cover exceeded 100% in all subplots sown with Cytisus, whereas it did not reach 65% in the others, when both species coexist together. There was an inverse correlation between the covers of both species and a positive correlation between the height of Erica australis and the cover and the height of Cytisus. There was no significant difference in Erica cover in plots sown with Cytisus and plots not sown. There could be some competition for light, but both species are capable of coexisting with high canopy overlap, for at least some time. Cytisus is expanding from the seeded subplots, suggesting that the dense cover of Erica australis does not impede the establishment of Cytisus.

Antioxidant and antimutagenic activities of plant extracts possess great potential as functional foods for cancer prevention. The aims of the current study were to evaluate antioxidant and antimutagenic activities and to study the chemical constituents of five Thai edible plant extracts. Antioxidant activity was expressed as the ability of each extract to scavenge the free radicals 1,1-diphenyl-2-picrylhydrazyl (DPPH). Antimutagenic activity was evaluated with the Ames test using Salmonella typhimurium strains TA 98, and TA 100. The results showed that Oroxylum indicum (Linn.) Kurg. and Tiliacora triandra Diels. extracts had high antioxidant activity with the EC 50 values at concentrations of 12.69 ± 1.02 and 14.51 ± 0.67 g/ml, respectively, whereas Basella alba Linn. extract had the strongest antimutagenicity with both strains of S. typhimurium with percentage of inhibition values ranging from 54.06 ± 1.52 to 86.08 ± 2.78 %. In the present study, flavonoids and phenolic compounds from the herbal extracts are proposed to be antioxidant and antimutagenic agents, respectively. The apparent antioxidant and antimutagenic activities of Thai edible plants further suggests their potential usefulness in cancer prevention.

Pedidos de restituição de peças a museus da América do Norte e da Europa por governos, instituições e coletivos africanos têm ganhado cada vez mais destaque. Alguns museus estão se dedicando a investigar a proveniência dos seus artefatos e a formar parcerias com as "comunidades de origem" para reexaminar suas abordagens em relação à conservação, catalogação e exibição. Com base em dados coletados em uma pesquisa etnográfica em vilarejos da floresta do Mayombe, na República Democrática do Congo, este estudo analisa um conceito-coisa chamado na língua kiyombe de kímbiindi. Por um lado, indico como este conceito-coisa atualiza memórias do tráfico transatlântico de pessoas escravizadas, tendo se tornado uma força perturbadora que pode gerar desconfiança entre os habitantes. Por outro lado, sugiro que o kímbiindi esteja relacionado a duas esculturas de acervos museológicos já analisadas pela história da arte (podendo ser uma das suas expressões materiais e/ou visuais). A análise permite discutir a diáspora africana a partir da África Central e dialoga com a antropologia dos museus, apontando tanto as oportunidades quanto os desafios das práticas colaborativas com as comunidades de origem dos artefatos.

A survey was conducted in Hamer and Bena-Tsemay pastoral and agro-pastoral districts of South Omo zone, south western Ethiopia in between January to May 2011with the objective to describe grazing management of goats and strategies to alleviate dry season feed shortage. Data were collected from the two districts by informal and formal survey methods using focused group discussion and semi-structured questionnaire administered to 250 households. Natural pastures from rangelands are major feed sources for goats. The households have different grazing sites and herd management strategies for cattle and small ruminants. Cattle graze on communal rangelands far away from the homesteads and herded by young boys who live in camps around the grazing site. On the other hand, sheep and goats, including a few lactating cows and some sick animals, graze in community rangelands around the homesteads. In Hamer and Bena-Tsemay districts, 85 and 46% households co-graze sheep and goats which are usuall...

Cet article propose une mise à jour de la phytosémiotique en articulant codes, signes et actes de transformation au sein du vivant végétal. À partir de l’héritage d’Uexküll et des apports de la biosémiotique, il montre comment les plantes interprètent des informations et modèlent leur Umwelt par des processus matériels de signification, du niveau cellulaire à l’écologique. En reconsidérant l’auto-organisation comme un phénomène sémiotique, le texte discute la pertinence de notions comme lecture, mémoire et apprentissage appliquées aux végétaux, en dialogue avec les théories de Barbieri (sémiotique minimale) et des approches contemporaines de la sensibilité végétale. L’argument central défend une continuité des interactions sémiotiques et met en évidence le rôle des codes (biochimiques, électriques) dans la production d’actions transformantes, soulignant ainsi la dimension matérielle, située et relationnelle de la signification chez les plantes.

Fire severity is predicted to increase in boreal regions due to global warming. We hypothesized that these extreme events will alter regeneration patterns of black spruce (Picea mariana). To test this hypothesis we monitored seed dispersal and seedling emergence, survival and growth for six years from 2005 to 2010 after the 2004 wildfire on Poker Flat, interior Alaska, using 96 1 m × 1 m plots. A total of 1,300 seedlings of black spruce and three broad-leaved deciduous trees (Populus tremuloides, Betula papyrifera and Salix spp.) were recorded. Black spruce seedlings colonized burned and unburned ground surfaces for the first two years after the wildfire and established on any topographical surface, while the broad-leaved trees emerged less in areas of lower elevation, slope gradient and canopy openness and only on burned surfaces. Vascular plant cover on the ground floor increased the seedling establishment of black spruce and broad-leaved trees, most likely because of seed trap effects. Black spruce grew faster on burned surface than on unburned surfaces. However, broad-leaved trees grew faster than black spruce on burned surfaces. Black spruce regenerates even after severe wildfire when the microtopography restricts the colonization of broad-leaved trees. The regeneration trajectories are determined soon after wildfire by a combination of seed limitation for black spruce and habitat preference for broad-leaved trees. Keywords Boreal forest • Broad-leaved trees • Burned ground surface • Microtopography • Seed dispersal • Seedling recruitment and survival • Wildfire

This study was designed to examine the subtle effects of habitat, aspect and altitude on plant diversity and the timing of phenological stages. In this increasingly arid region, within-species differences would cause more reproductive isolation of local populations, making species more vulnerable to regional extinction. Fifty-two sites in the Jebel Marra region of the Central Darfur state of Sudan were compared in terms of species diversity and local variation in the phenology of plant communities. Five habitat types were compared: sandy plains, clay plains, wadis, north-facing slopes and southfacing slopes. Sites were classified into five altitudinal zones ranging from 750 m to > 1,150 m above sea level, and the phenology of three categories of plant life form (phanerophytes, chamaephytes and therophytes) was tracked in terms of the duration of each phenophase (vegetative, reproductive and dormant). Overall, most plants were dormant from December to April. Peak vegetative growth was in July, coinciding with peak rainfall in all study sites in the region (July-August). This was followed by peak reproduction in October. Life form and habitat type significantly affected the length of all phenological phases; altitude significantly affected all stages except the duration of dormancy. Some of the interactions between these factors were also statistically significant, indicating subtle regulation of the duration of phenophases. The possible impacts of overgrazing and ongoing climate change are discussed, with the concern that initiation of vegetative growth in most habitats (except the clay plains) appears to be triggered by day length, 'anticipating' the beginning of the rainy season. Further climate change may uncouple this signal and the beginning of the rainy season, impacting plant survival. Keywords phenology . arid savannah . life form . altitude . habitat type . Darfur . Sudan

The seed bank of Neurada procumbens, a prostrate annual common in sandy desert habitats, is vulnerable to surface disturbances. Moreover, its seeds are highly heteromorphic, having both spinose and non-spinose sides, which affects both the vertical distribution of seeds and diaspores, and the precise position in which they lie in the soil. Here we explore the ecological implications of two factors, "safe sites" within habitats and seed orientation or "safe sides", on seedling establishment and the seed bank. In three natural populations, the vertical distribution of buried, germinable diaspores decreased with soil depth. Most diaspores occurred at the surface (0-1 cm below the surface), while none were observed below 10 cm. Seedling emergence decreased with depth and reached zero in diaspores below 5 cm. Seedling emergence also proved highly sensitive to the orientation of diaspores in soil. Diaspores lying on their smooth side with the spinose upper side directed upwards reached the highest seedling emergence of 61 %. Root length ranged from 10 to 16 cm, and the root to shoot ratio varied between 22.8 and 30.3 cm, depending on diaspore size. Diaspores near the surface may constitute a more transient component of the seed bank, as few of these remained viable for more than a year. Persistence of Neurada seed banks seems to depend not only on vertical movement of diaspores among habitat "safe sites" but also on different seed position alternatives.

Produktivitas primer tumbuhan adalah akumulasi biomassa yang didapatkan dari hasil fotosintesis. Tujuan pada praktikum ini untuk mengetahui dan memahami prinsip serta metode pengukuran produktivitas tanaman. Metode yang digunakan untuk mengetahui produktivitas tanaman uji adalah dengan metode sampling langsung dengan cara estimasi berat kering di mana seluruh tanaman hasil uji kompetisi akan dibersihkan dan ditimbang untuk mengetahui berat basah dan berat keringnya. Pada penimbangan berat kering digunakan oven dengan suhu 120 o Celcius untuk membantu mengurangi jumlah air yang terdapat pada tanaman. Penimbangan berat kering dilakukan beberapa kali untuk mengetahui grafik pengurangan air pada tanaman. Digunakan berat kering untuk melakukan perhitungan biomassa untuk mengindari pengaruh variabel kandungan air pada tumbuhan. Diperoleh persentase produktivitas dari Solanum melongena sebesar 87,% dan Capsicum annuum sebesar 84% dengan biomassa S. melongena lebih besar, yaitu 23,9 g/m 2 daripada biomassa akhir C. annuum sebesar 3,7 g/m 2. Perbedaan tingkat produktivitas ini dipengaruhi oleh faktor kompetisi jarak tanam dan komposisi biopolimer.

En la zona central de Chile se encuentra el bosque espinoso de Acacia caven y Prosopis chilensis, donde persiste menos del 40% de su superficie original, aunque sin representación en las áreas silvestres protegidas. Debido a la acción del ganado, se ha sugerido una contracción poblacional de P. chilensis acoplado a una expansión poblacional de A. caven lo cual, sin embargo, no ha sido verificado empíricamente. En cuatro sitios correspondientes a dos microcuencas de la Región Metropolitana en Chile (Batuco y Huechún), se evaluó la incidencia de las perturbaciones ambientales (ganado, conejos, malezas, basuras), el estado fitosanitario y estructura poblacional de P. chilensis, así como las dinámicas de regeneración de este árbol y A. caven, mediante el uso de matrices de transiciones Markovianas. Las poblaciones de P. chilensis enfrentan similares grados de amenaza, exhiben un estado fitosanitario similar y deficitario y, consecuentemente, se encuentran en estado senescente prontas a desaparecer una vez muertos los individuos adultos de las siguientes dos generaciones. Además, la contracción poblacional de P. chilensis no se correlaciona con una expansión poblacional de A. caven, por lo cual las dos especies que definen y caracterizan el bosque espinoso de la Región Metropolitana de Chile se encuentran prontas a extinguirse y con ellas el piso vegetacional. Surge, por lo tanto, como necesidad urgente el establecer las medidas de conservación y restauración necesarias para asegurar la persistencia del bosque espinoso en la Región Metropolitana de Chile.

Setaria viridis has recently emerged as a promising genetic model system to study diverse aspects of monocot biology. While the post-germination life cycle of S. viridis is approximately 8 weeks long, the prolonged dormancy of freshly harvested seeds can more than double the total time required between successive generations. Here we describe methods that promote seed germination in S. viridis. Our results demonstrate that treating S. viridis seeds with liquid smoke or a GA 3 and KNO 3 solution improves germination rates to 90% or higher even in seeds that are 6 days post-harvest with similar results obtained whether seeds are planted in soil or on gel-based media. Importantly, we show that these treatments have no significant effect on the growth of the adult plant. We have tested these treatments on diverse S. viridis accessions and show variation in their response. The methods described here will help advance research using this model grass species by increasing the pace at which successive generations of plants can be analyzed.

In this study vegetation composition of understorey species of Malam Jabba forest is evaluated by multivariate analysis. Thirteen stands were quantitatively sampled by point centered quarter method. Environmental variables were recorded and correlate them with vegetation characteristic. In 13 stands 49 understory species were recorded. Multivariate techniques were employed to assess the vegetation groups and underlying group structure. Agglomerative Cluster analysis (Ward’s method) discloses four main groups of vegetation while Principle Component Analysis (PCA) clearly ordinate these groups on all three axes. The most common species distributed in all four groups were Adiantum capillus veneris, Adiantum venestum, Berberis lyceum, Chrysopogon aucheri, Oxalis corniculata, Pteris cretica and Trifolium repens while these species were observed in three groups i.e.  Punica granatum and Plantago amplexicaulis. The Group 1 comprises on 23 species and the dominant species were Androsace rot...

Recent collections by the authors and others have yielded a new North American record, 38 additional new vascular plant state records for Indiana, and an additional five collections deemed noteworthy due to being recent observations of species that were considered extirpated from Indiana when they were discovered. Voucher specimens for all new records reside at various herbaria.

decidua) and silver fir (Abies alba). Samples associated with 20 bark beetle species and weevils were collected from nine stands in Poland and the Czech Republic. Fungi were isolated from adult beetles and galleries. Isolates were identified based on morphology, DNA sequence comparisons for four gene regions (ITS, LSU, ß-tubulin, TEF 1-α) and phylogenetic analyses. In total, 46 distinct taxa were identified, including 25 known and 21 currently unknown species. Several associations between fungi and subcortical insects were recorded for the first time. In addition, O. borealis and O. quercus were detected from A. alba for the first time. The composition of the fungal communities varied among the studied tree species and to a lesser degree among the beetle species. The spruce-infesting bark beetles were commonly associated with species of Leptographium s. l. and Ophiostoma s. str.; the larch-infesting bark beetles were often associated with Ophiostoma s. str. and Sporothrix, while the fir-infesting bark beetles were commonly associated with Ophiostoma s. str. and Graphilbum. The most commonly encountered fungal associates of the examined insects were (a) Grosmannia cucullata, G. piceiperda, Grosmannia sp. 1, Ophiostoma macroclavatum and O. piceae with the spruceinfesting bark beetles; (b) O. pseudocatenulatum and Sporothrix sp. 1 with the larch-infesting bark beetles; and (c) O. piceae, Ophiostoma sp. 2 and Graphilbum sp. 2 with the fir-infesting bark beetles. The differences in fungal associates among the bark beetle species occurring on P. abies, L. decidua and A. alba could be linked to the different habitats that these beetles occupy.

The composition and abundance of fi lamentous fungi species associated with Monochamus galloprovincialis and Acanthocinus aedilis on Pinus sylvestris in southern Poland were studied. Fungi were isolated from A. aedilis adults and M. galloprovincialis adults and their galleries, collected from three pine stands. In total, 214 fungal isolates from A. aedilis insect bodies and 232 fungal isolates from M. galloprovincialis adults were obtained; 1569 fungal isolates representing 39 species were obtained from M. galloprovincialis gallery systems. The most important groups of fungi were ophiostomatoid fungi and molds, including Mucor, Penicillium and Trichoderma species. Among ophiostomatoid fungi, Ophiostoma minus and O. piceae were the most frequently isolated species from A. aedilis and M. galloprovincialis adults, respectively. Ophiostoma minus was the dominant species in M. galloprovincialis galleries, with a frequency of 41%. Another relatively common fungus was Graphium sp. 'W', whereas other ophiostomatoid species were only occasionally isolated.

Assessment of factors regulating root decomposition is needed to understand carbon and nutrient cycling in forest ecosystems. the objective of this study is to examine the effects of soil depth and root diameter on root decomposition and to analyze the relationship of root decomposition with factors such as soil environmental conditions and initial litter quality. two decomposition experiments were conducted in natural pine (Pinus densiflora) and oak (Quercus serrata) forests over a 2-year period using the litterbag technique. For the soil depth experiment, 216 litterbags containing fine roots (∅ = 0-2 mm) were buried at 0-10-, 10-20and 20-30-cm soil depths. Soil properties and soil enzyme activities and microbial biomass at each soil depth were analyzed. For the root diameter experiment, 216 litterbags containing roots 0-1-, 1-2-and 2-3-mm in diameter were buried at 10-cm soil depth. the initial litter qualities (carbon (c), nitrogen (N), calcium (ca) and phosphorus (P) concentrations) for each of the root diameter classes were analyzed. Litterbags were retrieved after 3, 6, 12 and 24 months in each forest type. Important Findings the root decomposition rate was significantly altered by soil depth and root diameter. After 2 years, the root decay constant at 0-10-cm depth (pine: 0.35 and oak: 0.41) was significantly higher than that at 10-20-cm (0.31 and 0.37) and 20-30-cm (0.32 and 0.33) depths in the P. densiflora and Q. serrata forests. Enzyme activities and microbial biomass declined with soil depth, which may be associated with decreasing soil moisture and organic matter. the decay constant for the 0-1-mm roots (pine: 0.32 and oak: 0.37) was higher than that of 1-2-mm (0.29 and 0.33) and 2-3-mm roots (0.26 and 0.33) for the P. densiflora and Q. serrata forests. Difference in initial P concentration and c/N ratio among the different diameter roots were linearly related with root decomposition. In particular, the increasing c/N ratio with root diameter resulted in decreases in the decomposition rate. these results indicate the surface soil microbial activities and initial c/N ratio of root litter as important drivers of c dynamics in temperate pine and oak forests.

Damietta Branch; one of the two main branches of the River Nile has a length of about 242 km with an average width of 200 m and depth varying between 12 and 20 m. It receives polluted waters from different sources including industrial, agricultural and urban sewage that are causing serious environmental impacts on its vegetation and freshwater. The total number of plant species in the study area is 70, belonging to 54 genera and related to 30 families. These species can be classified ecologically into four major groups, three submerged hydrophytes, six floating hydrophytes, seventeen emergent species and 44 canal bank species. On the basis of duration, the recorded 70 species are grouped into two categories: perennials (46 species) and annuals (24 species). Hydrosoil and water variables which significantly correlated with the abundance and distribution of vegetation groups are soil texture (sand and silt), water-holding capacity, electrical conductivity, soluble anions (chloride and...

Agave salmiana is a native plant species harvested for the commercial production of mezcal (Agave spirits) in the highlands of central Mexico. The objective of this study was to identify vegetation changes in natural communities where A. salmiana has been differentially harvested for commercial purposes. Three plant community categories were identified in the state of Zacatecas based on their history of A. salmiana utilization: short (less than 10 years of use), moderate (about 25 years), and long (60 or more years). Species cover, composition, and density were evaluated in field surveys by use category. A gradient of vegetation structure of the communities parallels the duration of A. salmiana use. Agave salmiana density was greatest (3,125 plants ha -1 ) in the short-use areas and less (892 plants ha -1 ) in the moderate-use areas, associated with markedly greater density of shrubs (200%) and Opuntia spp. (50%) in moderate-use areas. The main shrubs were Larrea tridentata, Mimosa biuncifera, Jatropha dioica and Buddleia scordioides while the main Opuntia species were O. leucotricha and O. robusta. Agave salmiana density was least (652 plants ha -1 ) in the long-use areas where shrubs were less abundant but Opuntia spp. density was 25% higher than in moderate-use areas. We suggest that shrubs may increase with moderate use creating an intermediate successional stage that facilitates the establishment of Opuntia spp. Long-term Agave use is generating new plant communities dominated by Opuntia spp. (nopaleras) as a replacement of the original communities dominated by A. salmiana (magueyeras).

A special display titled "Biodiversity of the Woods in the Nagoya University Campus" was held as one of the programs for the Homecoming Day 2009 on 24th October. The display introduced the biodiversity of the campus with special references on the woods, insects and birds, demonstrating that the university obtains natural environments and harbors a wide diversity of organisms for the campus located in urban district.

We assessed the photosynthetic responses of eight wheat varieties in conditions of a simulated heat wave in a transparent plastic tunnel for one week. We found that high temperatures (up to 38 °C at midday and above 20 °C at night) had a negative effect on the photosynthetic functions of the plants and provided differentiation of genotypes through sensitivity to heat. Measurements of gas exchange showed that the simulated heat wave led to a 40% decrease in photosynthetic activity on average in comparison to the control, with an unequal recovery of individual genotypes after a release from stress. Our results indicate that the ability to recover after heat stress was associated with an efficient regulation of linear electron transport and the prevention of over-reduction in the acceptor side of photosystem I.

The diversity of marine algae of the eastern Caraga in the southern Philippines has remained largely undocumented and this presents an obstacle towards their utilization and conservation. Published literature was surveyed extensively and yielded 64 species and one variety classified under 42 genera, 21 families and 10 orders of marine red algae. A number of potential economic species with food, medicinal and industrial applications was found. However, this number is considered low when compared with similar environments and is likely not representative of the actual diversity there but instead suggesting lower sampling efforts, among other things. The baseline information may be useful in the formulation of policies for guided economic exploitation and contributing towards species and marine ecosystem conservation.