Composición, riqueza y abundancia de coleópteros (Coleoptera) asociados a bosques semideciduos y vegetaciones ruderales en la Sierra del Rosario, Cuba

En tres bosques semideciduos y en tres tipos de vegetación ruderal del Área Protegida de Recursos Manejados Mil Cumbres (Sierra del Rosario, Pinar del Río, Cuba), se analizan las comunidades de coleópteros y se las compara respecto a la composición, riqueza, abundancia, diversidad, equitatividad, ordenación y complementariedad. La composición de coleópteros conocida hasta el momento es de 166 especies, incluidas en 75 géneros y 34 familias. La vegetación ruderal presentaó mayor riqueza y abundancia que los bosques semideciduos. El bosque y la vegetación ruderal de Pan de Guajaibón exhibieron los valores más altos de riqueza, abundancia y número de especies únicas. Ambas formaciones vegetales de Sierra Chiquita presentaron la mayor diversidad y equitatividad. Las comunidades de coleópteros más afines estaban entre los bosques y entre la vegetaciones ruderales en Forneguera y Pan de Guajaibón. Cada bosque y tipo de vegetación ruderal presentaba especies exclusivas.

A PCR based method to detect Russula spp. in soil samples and Limodorum abortivum roots in Mediterranean environments

Aim of study. Orchidaceae has the largest number of species of any family in the plant kingdom. This family is subject to a high risk of extinction in natural environments, such as natural parks and protected areas. Recent studies have shown the prevalence of many species of orchids to be linked to fungal soil diversity, due to their myco-heterotrophic behaviour. Plant communities determine fungal soil diversity, and both generate optimal conditions for orchid development. Area of study. The work was carried out in n the two most important natural parks in Alicante (Font Roja and Sierra Mariola), in South-eastern of Spain. Material and Methods. We designed a molecular tool to monitor the presence of Russula spp. in soil and orchids roots, combined with phytosociological methods. Main results. Using a PCR-based method, we detected the presence in the soil and Limodorum abortivum orchid roots of the mycorrhizal fungi Russula spp. The species with highest coverage was Quercus rotundifolia in areas where the orchid was present. Research highlights. We present a useful tool based on PCR to detect the presence of Russula spp. in a natural environment. These results are consistent with those obtained in different studies that linked the presence of the mycorrhizal fungi Russula spp. in roots of the species Limodorum and the interaction between these fungal species and Quercus ilex trees in Mediterranean forest environments.

Efectos de la erosión del suelo sobre los patrones de la vegetación y su composición florística. Una revisión bibliográfica

En este artículo se revisan los estudios realizados sobre la influencia que tienen los procesos erosivos sobre la vegetación. Fundamentalmente se revisan las tendencias generales en la composición florística de las comunidades vegetales sometidas a fuertes procesos erosivos, así como las tendencias de los patrones de la vegetación y, en menor medida, de los atributos y tipos de plantas. Este campo de trabajo presenta pocos precedentes, siendo escasos los estudios de la influencia de la erosión sobre la vegetación desde un punto de vista ecológico-botánico. Por otro lado, algunos de los resultados parecen a primera vista contradictorios, por lo que es difícil extraer tendencias generales y más o menos universales. Algunas de las generalidades observadas son que el incremento de la erosión del suelo produce un descenso muy claro y mantenido en la cobertura vegetal y en el número de especies. El proceso erosivo no suele acarrear una sustitución de especies vegetales y comunidades, sino solamente la pérdida paulatina de especies, al menos en los estadios más degradados. Por otro lado, se ha observado en ocasiones que la flora de los terrenos más erosionados depende muy fuertemente de las características de la roca madre, variando más entre litologías que la flora de terrenos menos erosionados. Los hemicriptófitos y los caméfitos son las formas vitales de Raunkiaer más frecuentes en estos ambientes. Se discute el papel que pueden tener las diferencias de clima, procesos y tasas erosivas para explicar la gran diversidad de tendencias observadas.

Remote Sensing of Vegetation Change Across a Latitudinal Gradient in the Canadian Arctic

Global air surface temperatures and precipitation have increased over the last several decades resulting in a trend of greening across the Circumpolar Arctic. The spatial variability of warming and the inherent effects on plant communities has not proven to be uniform or homogeneous on global or local scales. We can apply remote sensing vegetation indices such as the Normalized Difference Vegetation Index (NDVI) to map and monitor vegetation change (e.g., phenology, greening, percent cover, and biomass) over time. It is important to document how Arctic vegetation is changing, as it will have large implications related to global carbon and surface energy budgets. The research reported here examined vegetation greening across different spatial and temporal scales at two disparate Arctic sites: Apex River Watershed (ARW), Baffin Island, and Cape Bounty Arctic Watershed Observatory (CBAWO), Melville Island, NU. To characterize the vegetation in the ARW, high spatial resolution WorldView-2 data were processed to create a supervised land-cover classification and model percent vegetation cover (PVC) (a similar process had been completed in a previous study for the CBAWO). Meanwhile, NDVI data spanning the past 30 years were derived from intermediate resolution Landsat data at the two Arctic sites. The land-cover classifications at both sites were used to examine the Landsat NDVI time series by vegetation class. Climate variables (i.e., temperature, precipitation and growing season length (GSL) were examined to explore the potential relationships of NDVI to climate warming. PVC was successfully modeled using high resolution data in the ARW. PVC and plant communities appear to reside along a moisture and altitudinal gradient. The NDVI time series demonstrated an overall significant increase in greening at the CBAWO (High Arctic site), specifically in the dry and mesic vegetation type. However, similar overall greening was not observed for the ARW (Low Arctic site). The overall increase in NDVI at the CBAWO was attributed to a significant increase in July temperatures, precipitation and GSL.

Community dynamics of stabilized dune xerophytic shrubs

Tese de doutoramento, Biologia (Ecologia), Universidade de Lisboa, Faculdade de Ciências, 2016

Ausmass und Auswirkungen der Waldbrände auf die Vegetation der Schweiz im Laufe der Jahrtausende

New palaeoecological investigations (pollen, macrofossil, and charcoal analyses) provide important evidence on the fire history and the long-term fire ecology of different regions of Switzerland. The results from the Swiss plateau, the Northern and Central Alps and Southern Switzerland suggest that fire played a different role for the long-term vegetational development in the different regions. In the Northern Alps and Southern Switzerland anthropogenic fires led to the disappearance of entire forest communities. These fires especially affected the fire-sensitive species Abies alba. On the Swiss Plateau fire frequencies were markedly lower than in the Southern Alps. Nevertheless, fires probably led to a decline in the occurrence of fire-sensitive taxa such as Ulmus, Fraxinus excelsior or Tilia at lower altitudes (Fagus silvatica-Quercus belt). First evidences from the Central Alps suggest that forest fires were naturally more frequent in this continental region and that the vegetation might be better fire-adapted than the original (partly or completely vanished) plant communities of the Swiss Plateau, the Northern Alps and Southern Switzerland.

(Table 1) Granulometry, soil pH, carbonate content and color description of soil profiles obtained in Xinghai, Tibet

Large parts of the eastern half of the Tibetan Plateau are covered between (3,500) 4,000 and nearly 6,000 m a.s.l. by alpine sedge mats (key species Kobresia pygmea), which attain an extension of ca. 450,000 km**2. It is considered to be the world's largest alpine ecosystem. Moreover, there exist isolated (relic) forests in the same area up to an altitude of 4,700 m a.s.l. mainly consisting of juniper (Juniperus) and spruce (Picea). Large parts of the Kobresia ecosystem are expected to be a grazing-resistant replacement formation, replacing forests and grass-dominated plant communities due to human and/or climatic impact. Recently, a research project was launched to increase knowledge about the properties and genesis of these forests and sedge mats (Present-day dynamics and Holocene landscape history of fragmented forest biocoenoses in Tibet; headed by G. Miehe, Marburg).

Vegetative study at the Duck Field Research Facility, Duck, North Carolina /

"April 1976."

Reevaluation of vegetational characteristics at the CERC Field Research Facility, Duck, North Carolina /

"March 1983."

Repeated manual release in a young plantation : effect on Douglas-fir seedlings, hardwoods, shrubs, forbs, and grasses /

Includes bibliographical references (p. 11).

Soil Influence on Forest Vegetation Productivity and Patterns in the Eastern Cascades of Southern Oregon

Thesis (Master's)--University of Washington, 2016-06

Nitrogen ecophysiology of Heron Island, a subtropical coral cay of the Great Barrier Reef, Australia

Coral cays form part of the Australian Great Barrier Reef. Coral cays with high densities of seabirds are areas of extreme nitrogen (N) enrichment with deposition rates of up to 1000 kg N ha(-1) y(-1). The ways in which N sources are utilised by coral cay plants, N is distributed within the cay, and whether or not seabird-derived N moves from cay to surrounding marine environments were investigated. We used N metabolite analysis, N-15 labelling and N-15 natural abundance (delta(15)N) techniques. Deposited guano-derived uric acid is hydrolysed to ammonium (NH4+) and gaseous ammonia (NH3). Ammonium undergoes nitrification, and nitrate (NO3-) and NH4+ were the main forms of soluble N in the soil. Plants from seabird rookeries have a high capacity to take up and assimilate NH4+, are able to metabolise uric acid, but have low rates of NO3- uptake and assimilation. We concluded that NH4+ is the principal source of N for plants growing at seabird rookeries, and that the presence of NH4+ in soil and gaseous NH3 in the atmosphere inhibits assimilation of NO3-, although NO3- is taken up and stored. Seabird guano, Pisonia forest soil and vegetation were similarly enriched in N-15 suggesting that the isotopic enrichment of guano (delta(15)N 9.9parts per thousand) carries through the forest ecosystem. Soil and plants from woodland and beach environments had lower delta(15)N (average 6.5parts per thousand) indicating a lower contribution of bird-derived N to the N nutrition of plants at these sites. The aquifer under the cay receives seabird-derived N leached from the cay and has high concentrations of N-15-enriched NO3- (delta(15)N 7.9parts per thousand). Macroalgae from reefs with and without seabirds had similar delta(15)N values of 2.0-3.9parts per thousand suggesting that reef macroalgae do not utilise N-15-enriched seabird-derived N as a main source of N. At a site beyond the Heron Reef Crest, macroalgae had elevated delta(15)N of 5.2parts per thousand, possibly indicating that there are locations where macroalgae access isotopically enriched aquifer-derived N. Nitrogen relations of Heron Island vegetation are compared with other reef islands and a conceptual model is presented.

Quantitative trends in airborne loads of Celtis sinensis pollen and associations with meteorological variables in a subtropical Australian environment

Celtis sinensis is an introduced plant species to the southeastern region of Queensland that has had a destructive affect on indigenous plant Communities and its pollen has been identified as an allergen Source. Pollen belonging to C. sinensis was sampled during a 5-year (June 1994-May 1999) atmospheric pollen-monitoring programme in Brisbane, Australia, using a Burkard 7-day spore trap. The seasonal incidence of airborne C. sinensis pollen (CsP) in Brisbane occurred over a brief period each year during spring (August-September), while peak concentrations were restricted to the beginning of September. individual CsP seasons were heterogeneous with daily counts within the range 1-10 grains m(-3) on no more than 60 sampling days; however, smaller airborne concentrations of CsP were recorded out of each season. Correlation co-efficients were significant each year for temperature (p0.05) and relative humidity (p>0.05). A significant relationship (r(2)=0.81, p=0.036) was established between the total CsP count and pre-seasonal average maximum temperature; however, periods of precipitation (>2mm) were demonstrated to significantly lower the daily concentrations of CsP from the atmosphere. Given the environmental and clinical significance of CsP and its prevalence in the atmosphere of Brisbane, a Clinical population-based Study is required to further understand the pollen's importance as a seasonal sensitizing source in this region.

Effects of fire on the structure and composition of open eucalypt forests

Fires are integral to the healthy functioning of most ecosystems and are often poorly understood in policy and management, however, the relationship between floristic composition and habitat structure is intrinsically linked, particularly after fire. The aim of this study was to test whether the variability of habitat structure or floristic composition and abundance in forests at a regional scale can be explained in terms of fire frequency using historical data and experimental prescribed burns. We tested this hypothesis in open eucalypt forests of Fraser Island off the east coast of Australia. Fraser Island dunes show progressive stages in plant succession as access to nutrients decreases across the Island. We found that fire frequency was not a good predictor of floristic composition or abundance across dune systems; rather, its affects were dune specific. In contrast, habitat structure was strongly influenced by fire frequency, independent of dune system. A dense understorey occurred in frequently burnt areas, whereas infrequently burnt areas had a more even distribution of plant heights. Plant communities returned to pre-burn levels of composition and abundances within 6 months of a fire and frequently burnt areas were dominated by early successional species of plant. These ecosystems were characterized by low diversity and frequently burnt areas on the east coast were dominated by Pteridium. Greater midstorey canopy cover in low frequency areas reduces light penetration and allows other species to compete more effectively with Pteridium. Our results strongly indicate that frequent fires on the Island have resulted in a decrease in relative diversity through dominance of several species. Prescribed fire represents a powerful management tool to shape habitat structure and complexity of Fraser Island forests.

Bryophyte propagule banks in a feldmark on subantarctic Macquarie Island

Subantarctic Macquarie Island has substantial areas of feldmark on its plateau above 200 m altitude. Samples of the substrate (5.5 cm in depth) from bare areas of feldmark contained viable propagules of bryophyte species found at adjacent and distant sites on the island. In laboratory conditions propagules of 15 bryophyte taxa germinated, allowing interpretation of reasons for bare patches in feldmark: bryophytes were successful at colonizing stable ground but when surface movement was present, burial and/or damage of propagules and young plants prevented colonization. Spherical moss polsters found in cryoturbatic areas in feldmark, however, represent a growth form that can tolerate surface movement. A conceptual model illustrating processes associated with colonization dynamics of bryophytes on feldmark terraces is presented. Ten of the 15 germinated taxa were nonlocal taxa which currently grow in plant communities at lower and hence warmer altitudes on Macquarie Island. The presence of viable propagules of these taxa provide an immediate and constant potential for dramatic vegetation change with climate change.