Forest Border Research Articles

How to Raise a Wild Child: The Art and Science of Falling in Love with Nature by Scott D. Sampson

Book Reviews 306 University of Colorado, where she worked with the Children, Youth and Environments Center for Community Engagement. How to Raise a Wild Child: The Art and Science of Falling in Love with Nature Scott D. Sampson (2015). Boston, New York: Houghton Mifflin Harcourt, 352 pages. $25.00; ISBN: 978-0544279322 Author “Dr. Scott” serves as science advisor and host of the popular children’s television animated science show, Dinosaur Train. He is a Canadian paleontologist who came to Utah to teach at the University of Utah and be a curator at the Natural History Museum in 1999. Sampson gave up us his tenured professorship in 2007 to move to California to teach public science programs and write because he was so concerned about how few children have deep connections with nature in this digital age. As he was writing How to Raise a Wild Child in 2013 he became an executive with the Denver Museum of Nature and Science. Sampson spent his childhood immersed in the temperate rain forest bordering Vancouver, British Columbia. Frogs, ferns, his best friend and family shared his love of nature that led to his career as a scientist. He wrote How to Raise a Wild Child to share with adults the many research-based reasons that time in nature is vital to well-being and to offer a guide to the ways one can introduce children to nature’s majesty and mysteries. The book is written for a general audience and well-researched regarding the child/nature relationship and existing international efforts to connect more children to nature. Citations at the book’s end can lead the curious reader to the original research and would be useful to anyone structuring a new children’s nature program. Additionally, his suggested outdoor activities for children and adults together form the start of a curriculum. Sampson weaves nature mentoring tips while recounting adventures with Jade, his own young daughter, as they explore the natural world together. Whether they are sharing a “sit spot” to observe birds in the backyard or an animal tracking expedition with an experienced mentor, these father/daughter scenarios offer guidance on what is possible to do nearby and further from home. He emphasizes the importance of offering children engaging sensory experiences, not a spelling list of scientific animal and plant names. He encourages questioning, not answering. Sampson frequently refers to Richard Louv’s book, Last Child in the Woods (2008) that raised the alarm about the child/nature disconnect in today’s urban world. How to Raise a Wild Child has similarities but is certainly worth reading even if one has read Louv’s earlier book. Book Reviews 307 Sampson describes international efforts to create more naturalized areas in cities and more nature-connected children and youth. Sampson sees cities as the realms where we can make a shift towards incorporating nature into daily life most successfully due to population density and the possibility of engaging youth in urban projects such as incorporating more native plants and trees to bring back native wildlife into existing parks, yards, open spaces and school grounds. He posits that if children can help with the “re-wilding” of modern cities, the children will feel more connected to what they helped to make happen. I recommend the book to parents, teachers, grandparents, aunts, uncles and anyone who works with children and wants the joy of discovering nature with a child as part of life. It doesn’t matter if the children are pre-schoolers or highschoolers . I went for a walk along a nearby river today with two of my granddaughters ages 8 and 9. Wynne found a big walking stick to help her navigate the river stepping-stones and Aisha found a hidden treasure of red currants to pick and eat. We all found joy in being outside together seeing what we could see, tasting the wild fruits, feeling the warm sun and cool breeze on our skin. Review by Illène Pevec Illène Pevec, Ph.D. is a research associate with the Children, Youth and Environments Program in the Center for Community Engagement at the University of Colorado and the program director for Fat...

Effects of a Wildfire on Selected Physical, Chemical and Biochemical Soil Properties in a Pinus massoniana Forest in South China

Pinus massoniana forests bordering South China are often affected by wildfires. Fires cause major changes in soil properties in many forest types but little is known about the effects of fire on soil properties in these P. massoniana forests. Such knowledge is important for providing a comprehensive understanding of wildfire effects on soil patterns and for planning appropriate long-term forest management in these forests. Changes in soil physical properties, carbon, nutrients, and enzymes were investigated in a P. massoniana forest along a wildfire-induced time span consisting of an unburned soil, and soils 0, one, four, and seven years post-fire. Soil (0–10 cm) was collected from burned and unburned sites immediately and one, four, and seven years after a wildfire. The wildfire effects on soil physical and chemical properties and enzyme activities were significantly different among treatment variation, time variation, and treatment-by-time interaction. Significant short-term effects on soil physical, chemical, and biological properties were found, which resulted in a deterioration of soil physical properties by increasing soil bulk density and decreasing macropores and capillary moisture. Soil pH increased significantly in the soil one-year post-fire. Carbon, total nitrogen (N) and phosphorus (P), and available N and P increased significantly immediately and one year after the wildfire and decreased progressively to concentrations lower than in the unburned soil. Total potassium (K) and exchangeable K increased immediately after the wildfire and then continuously decreased along the burned time-span. Urease, acid phosphatase, and catalase activities significantly decreased compared to those in the unburned soil. In fire-prone P. massoniana forests, wildfires may significantly influence soil physical properties, carbon, nutrients, and enzyme activity.

Potential of MODFLOW to Model Hydrological Interactions in a Semikarst Floodplain of the Ozark Border Forest in the Central United States

Abstract Riparian shallow groundwater and nutrient movement is important for aquatic and forest ecosystem health. Understanding stream water (SW)–shallow groundwater (GW) interactions is necessary for proper management of floodplain biodiversity, but it is particularly confounding in underrepresented semikarst hydrogeological systems. The Modular Three-Dimensional Finite-Difference Ground-Water Flow Model (MODFLOW) was used to simulate shallow groundwater flow and nutrient transport processes in a second-growth Ozark border forest for the 2011 water year. MODFLOW provided approximations of hydrologic head that were statistically comparable to observed data (Nash–Sutcliffe = 0.47, r2 = 0.77, root-mean-square error = 0.61 cm, and mean difference = 0.46 cm). Average annual flow estimates indicated that 82% of the reach length was a losing stream, while the remaining 18% was gaining. The reach lost more water to the GW during summer (2405 m3 day−1) relative to fall (2184 m3 day−1), spring (2102 m3 day−1), and winter (1549 m3 day−1) seasons. Model results showed that the shallow aquifer had the highest nitrate loading during the winter season (707 kg day−1). A Particle-Tracking Model for MODFLOW (MODPATH) revealed significant spatial variations between piezometer sites (p = 0.089) in subsurface flow path and travel time, ranging from 213 m and 3.6 yr to 197 m and 11.6 yr. The current study approach is novel with regard to the use of transient flow conditions (as opposed to steady state conditions) in underrepresented semikarst geological systems of the U.S. Midwest. This study emphasizes the significance of semikarst geology in regulating SW–GW hydrologic and nutrient interactions and provides baseline information and modeling predictions that will facilitate future studies and management plans.

Replacing Grasslands with Pine Plantations on the Karkloof Plateau: The Edge Effects on Downslope Forest Understorey Birds

The aim of this study was to examine if and how the exposure of indigenous forest edges to flanking exotic pine plantations transform the avian community and forest ecosystem found in the forest periphery. I compared bird diversity indices between forest bordering grassland and forest bordering pine plantation at 10 study locations. At each location, understorey birds were sampled with mist nets at the edge (0 m) and progressively deeper into each forest interior in spring and autumn. Crown cover was measured at these sites in autumn. Crown cover decreased from the edge into the forest, more so in forest bordering plantation, and at 60 m was, on average, 18% lower than forest bordering grassland. Furthermore, in forest bordering grassland, bird species richness and total abundance (of individuals) increased with edge distance in both seasons, but in forest bordering plantation, these trends were absent. In addition, in forest bordering plantation, different dominant species were recorded in spring and spe...

Influence of windbreaks and forest borders on abundance and species richness of native pollinators in lowbush blueberry fields in Québec, Canada

AbstractLowbush blueberry (Vaccinium angustifoliumAiton (Ericaceae)) production is highly dependent on insect pollination to maximise yields. The current losses in honey bee (Apis melliferaLinnaeus (Hymenoptera: Apidae)) colonies pose a serious threat to the blueberry industry, raising interest in alternative pollinators. Abundance and diversity of native pollinators usually decreases with distance from natural habitats. In this study, we evaluated the effects of distance from wooded habitats such as windbreaks and forest borders on the presence of native pollinators in blueberry fields in Lac-St-Jean (Québec, Canada). Four treatments were compared: single-row, double-row, natural windbreaks, and forest borders. Pan-traps were placed at 5, 30, and 60 m from the windbreak or forest border. A total of 3878 native pollinators were collected and 81% were ground-nesting bees. The forest border was the only treatment with higher abundance and species richness on the periphery (5 m) of the field than at further distances, supporting the hypothesis that the presence of pollinators is favoured by habitats potentially offering more abundant and diverse nutritional resources. Our overall results reveal that native pollinators are distributed quite homogeneously in blueberry fields, suggesting that windbreaks are beneficial to native pollinator communities.

Nesting and pollen preference of Osmia lignaria lignaria (Hymenoptera: Megachilidae) in Virginia and North Carolina orchards.

Cavity-nesting megachilid bees in the genus Osmia, found throughout the Palearctic and Nearctic regions, are good candidates for domestication. In North America, Osmia lignaria Say has been reported to be an excellent pollinator of tree fruit and is currently being developed for commercial use in orchards. This is largely because of research over several decades with the western subspecies of this bee, Osmia lignaria propinqua Cresson, in western orchards. The behavior of the eastern subspecies, O. lignaria lignaria Say, in eastern orchards has not previously been reported. This study evaluated the nesting activity and pollen preference of a population of the eastern subspecies in five orchards in the foothills and piedmont regions of North Carolina and Virginia over a 2-yr period. Apple was present in all orchards and all were bordered by hardwood forest. Shelters were placed both within orchards and the forest border. Emergence dates, nest construction, and orchard bloom were monitored weekly. Bee populations increased by 2-3 times annually at most orchards. Pollen species comprising nest provisions from 720 individual nest cells were identified and quantified using scanning electron microscopy. The greatest amount of pollen (46-82%) was that of a small understory tree, Eastern redbud (Cercis canadensis L.), at all orchard sites where these trees were present nearby. The quantity of orchard pollen was relatively low, <20% at full apple bloom, except for one orchard (53%) without nearby redbud. O. lignaria lignaria appears to prefer Eastern redbud pollen over orchard pollen.

Transmission concomitante de trypanosomose humaine et animale : le foyer de Mandoul au Tchad

La trypanosomose est une maladie qui affecte à la fois l’homme et les animaux. Elle est provoquée par Trypanosoma sp. et cycliquement transmise par un vecteur, la glossine. Bien que cette maladie soit essentiellement endémique dans l’aire de distribution de son vecteur, les zones endémiques qui présentent une transmission active des deux types de la maladie ont rarement été décrites. Dans la présente étude, des enquêtes épidémiologique et entomologique ont été menées, puis les échantillons obtenus ont été analysés par la technique d’amplification en chaîne par polymérase (PCR). Au total, 13 410 personnes ont été examinées et 132 cas diagnostiqués. L’examen de 144 bovins par PCR a révélé l’infection de 33 d’entre eux, soit par Trypanosoma brucei (39 p. 100 des infections), soit par T. vivax (55 p. 100 des infections), soit par une coïnfection (deux animaux). Trois familles d’insectes (Glossinidae, Stomoxyinae et Tabanidae) ont été capturées à des densités variables. Glossina fuscipes fuscipes a été capturée uniquement dans la partie sud du foyer et la plus forte densité apparente (DAP = 0,56 glossine/piège/jour) a été observée dans la forêt galerie bordant les villages où a été diagnostiqué le plus grand nombre de malades. Les Tabanidae ont été présentes dans toutes les zones prospectées mais la plus forte densité (DAP = 15,55 tabanidés/piège/jour) a été observée dans la partie nord du foyer. Les stomoxes ont été absents de la zone prospectée la plus éloignée de la rivière. L’identification des trypanosomes chez l’homme et le bétail, et la présence du vecteur cyclique et des vecteurs mécaniques potentiels ont confirmé l’endémie de trypanosomose animale et humaine dans ce foyer. Seule une stratégie globale d’élimination permettrait de la contrôler durablement.

Contribuição dos poleiros artificiais na dispersão de sementes e sua aplicação na restauração florestal

http://dx.doi.org/10.5902/1980509814590O uso de poleiros artificiais é uma técnica eficiente para a restauração florestal. Os objetivos desse trabalho foram: (1) avaliar o efeito da presença de poleiros artificiais no número de sementes florestais depositadas em coletores; (2) identificar as síndromes de dispersão das sementes, e (3) analisar o efeito da distância da borda da floresta no aporte de sementes. As atividades de campo foram realizadas no município de Iguaba Grande, Rio de Janeiro, Brasil. Foram instalados 70 coletores de sementes (com 0,50 m de diâmetro) distribuídos em transectos distantes paralelamente 5, 15 e 35 m da borda da floresta em área de pasto abandonado e em um transecto de 10 m no interior da floresta. Cada transecto fora do fragmento recebeu dez coletores, instalados sob poleiros artificiais, e dez coletores, instalados sem poleiro. No interior do fragmento foram instalados dez coletores, sem presença de poleiro artificial. Durante três semanas de amostragem foram coletadas 418 sementes, sendo 242 zoocóricas (57,9%) e 176 anemocóricas (42,1%). A média de sementes com presença de poleiro artificial foi de 7,4 (± 3,9) sementes/m2/mês, enquanto na ausência de poleiro artificial, a média foi de foi de 1,7 (± 1,8) sementes/m2/mês, considerando simultaneamente sementes anemocóricas e zoocóricas. Diferentes distâncias da borda da floresta, até 35 m, não influenciaram no aporte de sementes zoocóricas e anemocóricas. A presença de poleiros artificiais levou a um aporte 118 vezes maior de sementes zoocóricas quando comparada aos coletores sem poleiros. Poleiros artificiais podem funcionar como estrutura catalisadora da restauração florestal, com significativo incremento no aporte de sementes zoocóricas.

SURVEILLANCE AND TRACKING OF ELEPHANTS USING VOCAL SPECTRAL INFORMATION

Human-elephant conflict is a major problem which leads to crop damage, human death and injuries caused by elephants, and elephants being killed by humans. Elephant Intrusion has been on the rise in the forest border areas with herds of elephants straying into human habitation and creating a great loss to their properties. The surveillance and tracking of elephants are difficult due to their size and nature of movement. In this paper, a method for detecting and tracking elephants along the forest border areas using the vocal communications of elephants is presented. Two approaches are used one is to find the spectral energy magnitude and the other to determine highest pitch frequency produced by elephants. A threshold is identified for the two approaches; once the elephant vocal communication signal crosses the limit an alert will be sent to the forest officials notifying them about the elephant intrusion to redirect the elephant back to the forest.

Role of allochthonous carbon in the energy of terrestrial invertebrate communities at different distances from the Black Sea and a freshwater lake (Isotopic Evidence)

Isotopic analysis has become an important tool in the study of lateral links between ecosystems. The isotopic composition of carbon in terrestrial and aquatic primary producers can differ significantly, which provides an opportunity to identify the “marine” or “freshwater” carbon in the tissues of terrestrial animals. We measured the isotopic composition of C and N in tissues of soil invertebrates and estimated the proportion of “aquatic” carbon in the energy budget of terrestrial food webs at different distances from the Black Sea and a freshwater lake. Terrestrial predators are actively subsidized with carbon from the Black Sea to distance of up to about 50 m. The carbon subsidy from the freshwater lake is significant in the zone extending no farther than the forest border (ca. 15 m). Thus, the effect of allochthonous organic matter on terrestrial communities in both cases manifests itself only in a relatively narrow coastal strip.

Dendroclimatic Reconstruction at Kilometer-Scale Grid Points: A Case Study from the Great Basin of North America

AbstractPreparing for future hydroclimatic variability greatly benefits from long (i.e., multicentury) records at seasonal to annual time steps that have been gridded at kilometer-scale spatial intervals over a geographic region. Kriging is commonly used for optimal interpolation of environmental data, and space–time geostatistical models can improve kriging estimates when long temporal sequences of observations exist at relatively few points on the landscape. A network of 22 tree-ring chronologies from single-leaf pinyon (Pinus monophylla) in the central Great Basin of North America was used to extend hydroclimatic records both temporally and spatially. First, the line of organic correlation (LOC) method was used to reconstruct October–May total precipitation anomalies at each tree-ring site, as these ecotonal environments at the lower forest border are typically moisture-limited areas. Individual site reconstructions were then combined using a hierarchical model of spatiotemporal kriging that produced annual anomaly maps on a 12 km × 12 km grid during the period in common among all chronologies (1650–1976). Hydroclimatic episodes were numerically identified using their duration, magnitude, and peak. Precipitation anomalies were spatially more variable during wet years than during dry years, and the evolution of drought episodes over space and time could be visualized and quantified. The most remarkable episode in the entire reconstruction was the early 1900s pluvial, followed by the late 1800s drought. The 1930s Dust Bowl drought was among the top 10 hydroclimatic episodes in the past few centuries. These results directly address the needs of water and natural resource managers with respect to planning for worst-case scenarios of drought duration and magnitude at the watershed level.

Spider diversity responds strongly to edge effects but weakly to vegetation structure in riparian forests of Southern Brazil

Riparian forests bordering open terrestrial environments may have three microhabitats differing in structure and conditions: a grassland/pasture-forest edge (GE), a forest interior (FI) and a river–forest edge. The influence of such edge effects and vegetation characteristics on spider diversity of riparian forests was evaluated in Southern Brazil. Four different rivers were sampled on the tree–shrub strata with a beating tray, twice per season for 2 years. There were six transects per river, two per microhabitat. We compared spider abundance, species richness and composition. Vegetation variables sampled were vertical structure and (horizontal) density, canopy height and cover. Overall 42,057 spiders were sampled, 28 spider families and 440 species. The FI had higher spider abundance than the edges. Average species richness differed among rivers. Microhabitats did not differ in average richness, although overall richness (from sample-based rarefaction) was higher for GE than FI. High abundances in FI may result from lowered stress due to abiotic conditions, while higher GE richness may result from a faunal superposition between forest species and those from the grassland/pasture. Only canopy cover returns a positive relationship with spider diversity (richness and adult abundance). This might result from more spider species preferring to build webs or hunt under low-light environments. Rivers had spider faunas differing in composition but among microhabitats species composition was the same. Vegetation structure has been hypothesized to affect spiders, but this impact might be best seen in specific subgroups or guilds within spiders, not in the whole assemblage.

Measuring and Modeling Shallow Groundwater Flow between a Semi-Karst Border Stream and Ozark Forested Riparian Zone in the Central USA

Aims: Quantitative information is limited pertaining to riparian forest and stream shallow groundwater interactions particularly in karst hydro-ecosystems. Study Design, Place and Duration: Spatiotemporal variability of shallow groundwater flow was monitored along two stream reaches in a riparian Ozark border forest of central Missouri, United States. Each reach was equipped with twelve piezometers and two stream-gauging stations during the 2011 water year (WY). Methodology: High-resolution (i.e. 15 minute) time-series data were analyzed indicating average groundwater flow per unit stream length was -3 x 10

An improved real time image detection system for elephant intrusion along the forest border areas.

Human-elephant conflict is a major problem leading to crop damage, human death and injuries caused by elephants, and elephants being killed by humans. In this paper, we propose an automated unsupervised elephant image detection system (EIDS) as a solution to human-elephant conflict in the context of elephant conservation. The elephant's image is captured in the forest border areas and is sent to a base station via an RF network. The received image is decomposed using Haar wavelet to obtain multilevel wavelet coefficients, with which we perform image feature extraction and similarity match between the elephant query image and the database image using image vision algorithms. A GSM message is sent to the forest officials indicating that an elephant has been detected in the forest border and is approaching human habitat. We propose an optimized distance metric to improve the image retrieval time from the database. We compare the optimized distance metric with the popular Euclidean and Manhattan distance methods. The proposed optimized distance metric retrieves more images with lesser retrieval time than the other distance metrics which makes the optimized distance method more efficient and reliable.

Decentralized Coordination of Constrained Fixed-wing Unmanned Aerial Vehicles: Circular Orbits

UAVs are promising platforms for various missions such as remote sensing of agricultural products, forest fire surveillance, search-and-rescue and border monitoring. A relevant common challenge in the above missions is that of convergence to an objective circular orbit. To address this challenge for fixed-wing UAVs, intrinsic constraints such as nonholonomic nature of the vehicle, minimum and maximum forward velocity, maximum angular velocity and limited detection range must be considered. In this paper, a decentralized coordination strategy is developed so that a number of fixed-wing UAVs converge to an objective circle, respecting the mentioned constraints. Also, a priority-based collision avoidance scheme is proposed to avoid inter-UAV collision. Convergence of the system is proved by analysis of the finite state machine associated with the coordination algorithm. Simulation results are presented to verify the feasibility of the proposed approach.

Adaptaciones estructurales de dos orquídeas epífitas simpátricas (Orchidaceae) en un bosque nuboso de un campo rupestre del sureste de Brasil

The survival of plants in epiphytic environments depends on vegetative adaptations capable to defraud different stresses. Based on the structural diversity of the Orchidaceae, the current study has the objective of relating the anatomical structure of Dichaea cogniauxiana and Epidendrum secundum with the distinct environments where they live. It was expected that, despite structural similarities as strategies for resource acquisition, some peculiar variations related to the distinct light microenvironments (inside or in the edge of the nebular forest, near to "campo rupestre" area) might be found. Leaves and roots of both species were collected in a nebular forest located at a "campo rupestre" area at Serra da Piedade, Brazil), in January and February 2005. D. cogniauxiana is adhered to trunks, in sites with high atmospheric humidity and shaded, while E. secundum is located at the edge of the nebular forest, in more luminous sites. The leaves of E. secundum had thicker cuticle and higher number of stomata per area than those of D. cogniauxiana, characteristics coherent with their distinct pattern of exhibition to sun light. The suprastomatic chambers formed by the thicker cuticle may function as a barrier of resistance to water evaporation. The succulence of the leaves of E. secundum propitiates organic acids storage at night, and the storage of starch may be involved in PEP-carboxylase metabolism, both propitiating CAM mechanism. Roots with larger number of cell layers of the velamen, and specialized thick walled cortical cells (both in E. secundum) help water absorption and indicate better adaptation to an environment with intense solar radiation and a probable higher water deficit. The remarkable cell wall thickening of E. secundum exodermis can confer more efficient protection against the excess of transpiration at the border of the nebular forest. On the other hand, besides D. cogniauxiana be epiphyte, it is in a low position - in a shaded environment and with high relative humidity. Its thin thickened velamen permits the entrance of the low available light, and photosynthesis, producing oxygen and helping to avoid hypoxia condition. As features registered for D. cogniauxiana and E. secundum roots, we can depict the velamen, distinct exodermis and endodermis, and specialized thick walled cortical cells as characteristic of epiphytic plants.

Polycyclic Aromatic Hydrocarbons (PAHs) in Sediments from the Ologe Lagoon, Nigeria

Surface sediments from the Ologe lagoon in Nigeria were analyzed for 28 polycyclic aromatic hydrocarbons using gas chromatography-mass spectrometry. The total concentrations of polycyclic aromatic hydrocarbons (Σ27PAHs), excluding perylene, and potential carcinogenic polycyclic aromatic hydrocarbons (ΣcPAHs) in the sediments ranged from 60 to 202 ng/g (average: 137 ng/g) and 4 to 60 ng/g (average: 21 ng/g), respectively. Two-ring polycyclic aromatic hydrocarbons were the dominant components accounting for approximately 54% of the total polycyclic aromatic hydrocarbons detected. The concentration of polycyclic aromatic hydrocarbons in the sediments indicated low level contamination when compared to those reported for similar samples from other regions of the world. Polycyclic aromatic hydrocarbons compound diagnostic ratios, phenanthrene/anthracene, and fluoranthene/pyrene suggested that the PAHs in the sediments were mainly from pyrogenic sources, which may have resulted from incomplete combustion of fossil fuel from surrounding industrial estates, or occasional forest burning in the Mangrove forest bordering the lagoon.

Urner Wald – Grundlage für eine nachhaltige Entwicklung (Essay)

The forests of the canton of Uri: the foundation of sustainable development (essay) The canton of Uri is characterised by extreme topography: steep slopes and narrow valleys. Limited space is a major challenge for the development of the canton. Prudent management of this mountainous area is necessary to ensure a safe and attractive environment. In this situation, the forest, or to be more precise, the management of the forest, plays a key role. Most of the forest area is classified as protection forest, which is an essential condition to guarantee safety. The overriding management objective for the protective forest is sustainability. The existence of the forest in all its forms is the necessary condition also for biodiversity and landscape beauty. There is strong demand for land on the valley floor, where the main challenge is to protect the few remaining forest areas. Elsewhere however, the forest is expanding and measures must be taken to stop it taking over completely. Forest operations have consequences beyond the forest borders. For these reasons, sustainable management of the forest resource is the foundation of sustainable development of the mountainous canton of Uri.

Export of 13C-depleted dissolved inorganic carbon from a tidal forest bordering the Amazon estuary

Tidal wetlands play a significant role in the coastal carbon cycle and exchange material with the atmosphere and coastal ocean. Here, we report on changes in dissolved inorganic carbon speciation and isotopic composition throughout a 24 h cycle (2 tidal cycles) in Feb. 2007 in a channel connecting the Amazon estuary to the basin of a tidal forest. At this site, tropical forest soils are inundated at high tide by estuarine freshwater, and temporal concentration changes in the channel reflect exchanges between the forest and estuary. Our data show an export of dissolved inorganic carbon (DIC) in the form of excess CO2 and, to a much lesser extent, CH4. However, the tidal forest traps suspended sediments. Mixing plots of DIC versus conductivity showed that the DIC originated from the tidal forest soil, with a negligible contribution from the local watershed. Evolution of the isotopic signature of DIC reveals a 13C-depleted source (−56.9 ± 3.3‰), presumably originating from a dominant methanogenic pathway of carbon mineralization followed by almost complete CH4 oxidation in the organic clay-rich freshwater soil.

Structure et diversité floristique des îlots de forêts riveraines communautaires de la Basse vallée de la Sô au Sud-Est du Bénin

Objective: This study aims to evaluate the structure and floristic diversity of the forest bordering the lower valley of the Sô southeast of Benin. Methods and Results: The floristic inventories and forestry products were conducted across 38 plots. In total, 75 species belonging to 69 genera and 31 families were surveyed. Plant communities were identified and characterized as the riparian forest to Mimusops kummel and Pterocarpus santalinoides, riparian forest Cola gigantea and C. laurifolia and riparian forest to Berlinia grandiflora and Dialium guineense. Plant and structural parameters varied from one group to another. Thus, species richness varies from 30 to 47 species, Shannon diversity index of 1.65 to 4.20 bits, Pielou evenness from 0.50 to 0.83 and the diversity of families is between 19 and 24 with a predominance of Leguminosae. Density varies from 247 to 641 stems / ha, basal area of 22.25 to 63.84 m² / ha, volume and biomass are between 85.62 and 471.01 m3/ha. Conclusion and application: The study showed the diversity of plant community forests. There is a recent increase in local biodiversity, but is subject to strong human pressure which requires urgent conservations action. The protection of these fragile ecosystems is crucial for southern Benin since it constitute a wetland of international importance (Ramsar 1018) and economic potential for the populations living on the lakeside. Keywords: Flora, community, Sô lower valley, South-East of Benin, West Africa. J. Appl. Biosci. 2013