Inland Vegetation Research Articles

The influences of anthropogenic modification after the Great East Japan Earthquake on ground insects and their relationship with vegetation

ABSTRACT On the Pacific coast of Northeastern Japan, tidal embankments and coastal forests were constructed following the Great East Japan Earthquake. Although coastal forests are regarded as green infrastructure, the impact of their reconstructions on ecosystems is concerning. To mitigate these impacts on the Sendai coast of Miyagi prefecture, non-modified areas were established, and coastal sand was covered over the mounds constructed as coastal forest beds. This study surveyed the distribution of ground insects and vegetation in this area to evaluate differences associated with these anthropogenic modifications and mitigations. The results showed that coastal insect abundance and vegetation coverage were lower on the mounds compared to the areas without afforestation or mounding. However, inland insect abundance and vegetation coverage was higher on the landward side of the tidal embankment compared to the seaward side, regardless of the mounds. On the landward side of the tidal embankment, coastal insect abundance was lower when inland vegetation coverage was dense. Additionally, no quantitative differences in coastal insects and plants were observed between the sand-covered mounds and not covered mounds. We suggest that the influence of green infrastructures such as coastal forests on the native ecosystem should be considered.

Spatial and temporal changes of land use land cover distribution in selected sites of the southern coastal zone of Sri Lanka

The southern coastal zone of Sri Lanka has been subjected to a variety of natural and anthropogenic influences over the past three decades. Understanding impacts of such influences on Land Use Land Cover (LULC) is vital for proper management of the coastal zone. This study, therefore, focused on mapping the change/s in the distribution of selected LULC in the selected sites, Bundala, Galle, Kalametiya, and Hambantota of the southern coastal zone, over last 24 years using satellite imagery. LULC maps of nine classes (mangrove, inland vegetation, marsh and grass, sand, bare land, built-up, cultivation, water, and unclassified) were created by employing an on-screen digitization technique achieving an accuracy of >70%. Trend analysis and two-sample proportion tests were used for statistical analyses, whereas geometric calculations were used for descriptive analyses. The results showed the highest overall change in LULC in Kalametiya, followed by Hambantota, Galle, and Bundala. The changes in the LULC classes are mainly attributed to the conversion of water to mangroves, marsh and grass areas in Kalametiya, water to built-up areas in Hambantota, cultivations to built-up areas in Galle, and marsh and grass areas to bare lands in Bundala. The causes of LULC changes were site specific. Trend analyses indicate the least LULC changes in Bundala possibly by 2025. The study highlights the significance of taking into account geographical dislocations when considering and anticipating the potential impacts of development projects over broader extents.

Satellite Image-Based Time Series Observations of Vegetation Response to Hurricane Irma in the Lower Florida Keys

High-resolution satellite imaging represents a potentially effective technique to monitor cyclone-caused environmental damage and recovery over large areas at a high spatial scale. This study utilized a 10-m resolution Sentinel satellite image series to document vegetation changes in a portion of the Florida Keys, USA, over which the core of Category 4 Hurricane Irma passed on 10 September 2017. A previously assembled field survey was used to establish land-cover patterns in the satellite data, and concurrent field measurements verified post-hurricane changes. Normalized difference vegetation index (NDVI) was utilized as a tracer for pre-storm baseline patterns and through 19 post-storm months. NDVI patterns show that the severity of vegetation damage varied appreciably across the area, with the least damage on islands in the western sector of the hurricane’s eye and around its center, and greatest damage on islands just east of the eye. The data reveal that for 2.5 months after the storm, multiple inland vegetation classes showed substantial early regrowth. However, mangrove forests were more negatively affected. The storm caused extensive mortality of black mangrove (Avicennia germinans) and red mangrove (Rhizophora mangle), corresponding to more than 40% of the total mangrove area on some islands. The full extent of mangrove die-off was not immediately evident, and increased progressively through the first few months after the storm. In addition to demonstrating the utility of high-resolution satellite image series for post-hurricane environmental assessment, this study reveals high-resolution links between vegetation types, their location within the cyclone, and the extent of post-storm recovery.

Effect of image radiometric correction levels of Landsat images to the land cover maps resulted from maximum likelihood classification

Radiometric correction of remote sensing images is required to improve the quality of image pixel values and provide a measurable physical unit of each pixel. Selection of the appropriate image radiometric and atmospheric correction level defines the success of any remote sensing-based mapping applications. This study aims to assess the effects of radiometric correction levels applied to Landsat 8 (Operational Land Imager, OLI) image acquired in 2018 to the results of the land cover classification using the Maximum Likelihood Classifier (MLC). The image was corrected into four levels of radiometric and atmospheric correction; no correction (digital number), at-sensor radiance, at-sensor reflectance (top of atmosphere, ToA), and at-surface reflectance (bottom of atmosphere, BoA). A set of classification training sample covering five land cover classes (mangroves, inland vegetation, exposed soil, built-up area, and water body) was selected from the image. To ensure fair class comparison, the number of training sample were set to be proportional to the area of targeted classes. The results of this study show that there is no difference in the classification results of each level of correction, both in the area and distribution of the classes. This finding indicates that MLC result is invariable of image correction level.

Investigating Role of Vegetation in Protection of Houses during Floods

Flood flows have the potential to cause substantial damage to infrastructure, mankind, livestock and agricultural land which all stacks up to greatly affect the financial condition of the region. During 2010 Pakistan floods, more than two million houses were damaged partly or totally [1]. To minimize these types of destructions, inland vegetation can be considered a natural barrier to dissipate the energy of flood flow and limits widespread inundation. This study involves volume of fluid (VOF) modelling approach to figure out the role of vegetation of finite width in energy reduction of flood flow, in front of houses, against: vegetation of varying Aspect Ratio (A/R width-length ratio) and distance between vegetation & houses (Lr). Channel domain was built in ANSYS workbench toolkit and meshing was done in meshing building toolkit. For the postprocessing and simulation, FLUENT was used. Various contour plots & profiles of cross stream-wise velocities and water level measurements are presented in this paper. The simulation results of cross stream-wise velocities and water level measurements were identical with experimental data. At vegetation upstream and downstream, velocity reduction observed in higher A/R (2.40) compared to vegetation of A/R-1. Whereas, outside the vegetation and near the walls of channel domain flow velocities were high. The water level was raised on the upstream side of the vegetation due to resistance offered by vegetation. On the upstream side of vegetation, the rise in backwater depth increased by increasing A/R. Contrarily, on the downstream side of vegetation, an undular hydraulic jump was observed in between vegetation and a house. By increasing A/R, the energy loss increases under constant vegetation conditions (G/d = 0.24, Fro = 0.70; G = spacing of each cylinder in cross-stream direction and d= diameter of cylinder and Fro = initial Froude number) and increase in house distance from 1W to 2W, the energy reduction increased from 2.40% to 3.15% which was further increased to 5.04% for another 5W increase in house distance, where W is the vegetation width. Simulation results also shown that with increasing Froude no from 0.60 to 0.70 water level depth has also an incremental pattern which ultimately results in increase in energy dissipation along the varying building distance (1W, 2W & 5W). Thus, to minimize the structural damage, a structure must be located at a safe distance away from the vegetation where flow becomes sub-critical.

Environmental gradients and micro‐heterogeneity shape fine‐scale plant community assembly on coastal dunes

AbstractQuestionsHow do fine scale community assembly processes (e.g., environmental filtering, symmetric competition, hierarchical competition, facilitation) vary along a natural stress gradient on coastal sand dunes? How does local environmental heterogeneity affect these processes?LocationMediterranean coastal sand dunes, central Italy (Montalto Marina, Lazio region).MethodsWe quantified spatial (co‐occurrence) and functional patterns (degree of divergence in the traits of co‐occurring species) at a fine scale (0.5 m × 0.5 m subplots) in herbaceous communities (2 m × 2 m plots) of coastal habitats along the sea–inland vegetation zonation. We then studied how the fine‐scale co‐occurrence patterns (aggregation vs segregation) varied across habitats of the zonation. Finally, we fitted linear models assessing the relationship of the fine‐scale functional patterns (convergence vs divergence) with (1) the average environmental conditions along the sea–inland environmental stress gradient, and (2) the environmental heterogeneity within plots.ResultsSpatial and functional patterns conveyed complementary information. Within‐community spatial segregation was more common further from the sea, which suggests the dominance of competitive processes in the least stressed communities. Fine‐scale convergence or divergence depended, for all functional traits, on the average environmental conditions of the community along the gradient, suggesting an effect of environmental stress on the prevailing assembly processes. However, it also depended on the environmental heterogeneity within the community, suggesting that micro‐abiotic filtering might play a more important role than previously anticipated in determining fine‐scale community assembly.ConclusionsOur results suggest that contrasting assembly processes act simultaneously on community assembly along environmental gradients, both as a function of average environmental conditions and of local heterogeneity. Future studies assessing community assembly should therefore avoid neglecting the role of micro‐abiotic filtering in shaping functional patterns. Moreover, only by integrating multiple sources of information (trait patterns, spatial patterns and environmental variation) were we able to disentangle fine‐scale community assembly processes and reinforce our interpretation of community patterns.

Middle Pleistocene to Holocene coastal evolution of NW Sardinia (Mediterranean Sea, Italy)

The Middle Pleistocene–Holocene Sardinian stratigraphy has been revised to identify the roles played by sea and climate changes in controlling sedimentation. The succession, dated through Optically Stimulated Luminescence (quartz, K-feldspar) and 14C (the most recent) was grouped into eight major stratigraphic units mainly represented by coastal dunes, shallow marine, and alluvial systems. These units range in age from MIS 8 (300 ka) to MIS1 (6 ka).Little information is available for the period between MIS 8 and 6. The available data, however, allow some comments on climate changes over the last 125 ka. The last interglacial (MIS 5) is subdivided into five substages (e–a). MIS5e (Eemian) is considered the climate optimum of this interglacial, sea level was 4–6 m higher than today, and climate conditions were warmer and more humid. MIS 5c is the second high stand peak. Sea level was about 1.5 m above the modern level, and paleoclimatic and paleogeographic conditions were similar to the present. During MIS 4, at the beginning of the glacial phase, a climatic deterioration occurred. Temperatures dropped by 6C° relative to MIS 5e in about 5 ka, and sea level fell about 60 m. This led to a progressive disruption of inland vegetation cover and to repeated valley slope denudation. The sea-level fall created the accommodation space for fan development in sheltered and cliffed areas, where debris flows developed and filled almost completely the terminal parts of the narrow coastal valleys/coves. In wider areas, however, coastal dune fields developed. Contemporaneous presence of alluvial fan and dune systems is associated with the local morphology that could mitigate or amplify moist conditions within a generally arid environment.During MIS 3, several climate fluctuations occurred (wet/arid, D/O-H events). However, the shallow Sardinian shelf was continuously sufficiently exposed to become the source area of bioclastic sands. These sands were blown inland, and formed extensive dunefield systems. Dunes dominated the west coasts of Sardinia under cold and relatively dry conditions. In some areas, these dunefield systems were eventually almost completely dismantled and reworked into water-flow dominated alluvial fans by catastrophic rainfall events. Thus, the local climate quickly switched from arid to humid conditions. No record of the last Glacial Maximum deposits, MIS 2, was observed along the NW Sardinian coast. During the Holocene transgression (MIS1) coastal dune systems developed and progressively migrated inland, and temperature rose to reach the present-day condition.

Natural History ofAmeerega flavopicta(Dendrobatidae) on an Island Formed by Três Marias Hydroelectric Reservoir in Southeastern Brazil

We studied a population of Ameerega flavopicta on an island in southeastern Brazil that was formed during the filling of a reservoir in 1965. We studied frog condition factor, diet composition (through induced regurgitation), prey preferences (based on prey availability assessed at frogs' habitats), vocalizations, breeding period, and density. We conducted fieldwork monthly from July 2008 to March 2010 to locate frogs in marked grids. We photographed individual frogs to register particular patterns of dots on the dorsum that allowed individual recognition. During the rainy season A. flavopicta used a temporary trench inside the inland vegetation (Cerradão) for tadpole development. The frogs migrated to the margins of the reservoir during the dry season, when the trench dried completely. Frogs measured 24.0 ± 4.0 mm (snout–vent length), and mass was 1.6 ± 0.5 g (N = 47). Their condition varied among months but not between the two areas used (trench surroundings inland and island shores). Ameerega flavopicta favored specific food items and preferred Lepidoptera larvae in both areas. The advertisement call was composed of simple notes repeated 102.7 ± 7.63 times per min, lasting 166 ± 42 msec and spaced by 387 ± 66 msec. The breeding period differed from that reported for other areas. This and other aspects of the Pirapitinga population differed from populations studied elsewhere. Differences may be attributable to a bottleneck effect or different selective pressures in this isolated population.

A Model of the Effect of Environmental Variables on the Presence of Otters along the Coastline of the Isle of Skye

A survey of Eurasian otters (Lutra lutra) along the Skye coastline revealed a variation in distribution on different coastal types. Factors like geology, width of the intertidal zone, intertidal makeup, slope of coastline, inland vegetation, and number of freshwater pools could influence otter distribution. A quantitative method based on a logistic regression model is applied to take into account three scalable and four categorical environmental variables which may or may not affect otter distribution. Otter presence or absence in 500 m coastal sections was compared with binary dependent variables and a set of independent variables on 622 coastal sites. Analysis shows that this method can be used to characterise combinations of factors to predict if otters are likely to occur on a particular coastline. Geology, height 25 m above High Water Mark (indicating slope of coastline), and number of freshwater pools all affect otter utilisation of the coastal zone. Coastlines with Torridonian and Mesozoic rocks and the Landslip area show a positive effect on otters, while all other coastlines have a negative effect. Although primarily of theoretical importance, the model could be used as a tool to locate coastlines elsewhere which are of potential conservation importance for otters.

Soil-Plant Relationships in the Arid Saline Desert of Cholistan

The inland vegetation of saline patches in the Cholistan desert faces extreme environmental conditions including predominantly salt stress and limited resource availability. Changes in the salinity gradients may lead to gradual variation in response of individual plant species that ultimately affect community structure and composition. The present study was conducted to determine spatial distribution of individual species along a salinity gradient in the Cholistan desert in relation to their life form and tolerance limits. The results showed variable responses of these species in spatial distribution against the salinity gradient. The plants differed considerably in their tolerance level due to development of differential adaptive strategies under extreme salinities. Excretory species like Aeluropus lagopoides and Sporobolus ioclados dominated the sites with highest salinities along with the leafy succulent Suaeda fruticosa. Stem succulents dominated moderate salinities along with spreading stoloniferous Ochthochloa compressa and tussock grass Cymbopogon jwarancusa. Non-succulent Cressa cretica and tussock grass Lasiurus scindicus were mainly distributed to sites with lower and moderate salinities, while non-succulent plants dominated the lowest salinity site. Of the soil physico-chemical characteristics in the Cholistan desert habitats, salinity may have a direct effect on the life form and survival strategies of occurring plants. Thus, the difference in spatial distribution of individual species along salinity gradients suggested that salinity alone is not a responsible factor to determine community structure, but plant tolerance limits and their life habits are also important.

Oligocene vegetation and climate characteristics in north-west Turkey: data from the south-western part of the Thrace Basin

In this paper we present the first palynomorph and mollusc assemblages from the sediments in three different sections. From east to west, these are the Şevketiye (northern Biga Peninsula), the Tayfur (Gelibolu Peninsula) and the Kuzu harbour (Gökçeada) (parts of the Danişmen Formation) sections in the south and south-western side of the Thrace Basin (north-west Turkey), with the aim of obtaining information about the composition and structure of vegetation and climate during the Oligocene. The stratigraphic interval extends from late Rupelian to Chattian. The Danişmen Formation in the Şevketiye section yielded a palynomorph association with abundant coastal palms (Arecaceae; Lepidocaryoidae), and mangrove pollen (Pelliciera). A similar assemblage from the Kuzu harbour section was also obtained, with minor contributions of mangrove elements Nypa and Acrostichum aureum, Arecaceae type palm, undifferentiated dinoflagellate cysts and microforaminiferal linings. These palynomorph assemblages, combined with the mollusc data, indicate that low-lying coastal environments prevailed. In contrast, the palynomorphs from the Tayfur section represent a non-marine environment lacking mangrove elements, palm trees, dinoflagellate cysts and microforaminiferal linings. The diversity of angiosperm taxa in the Tayfur palynoflora, which form the bulk of the assemblage, indicates terrestrial vegetation. Quantitative palaeoclimate analyses are based on the Coexistence Approach method, and yield over 22 °C at the coast as indicated by mangrove elements and palms in the Şevketiye and Kuzu harbour palynofloras. For the Tayfur palynoflora, mean annual temperature ranged between 16.5 and 21.3 °C. This indicates a climate cooling, corresponding to the transition from Rupelian to Chattian, and resulted in the pollen changes from mangrove bearing coastal deposits to more inland vegetation.

Classification of inland Bolboschoenus-dominated vegetation in Central Europe

Central European inland vegetation dominated by Bolboschoenus species was newly classified, based on current knowledge of taxonomic differentiation within the Bolboschoenus maritimus-complex. Altogether 225 phytosociological releves from the Czech Republic, Slovakia, Poland, Germany and Austria were analysed. Bolboschoenus-dominated vegetation is found in a broad range of both freshwater and saline habitats. Individual Bolboschoenus species grow in different habitats with different species composition. The freshwater vegetation, dominated by B. yagara, B. laticarpus and B. planiculmis, reflects ecological differentiation of these species from base-poor to alkaline substrates, and from littoral habitats to temporarily flooded depressions. The following freshwater associations were distinguished: Phalarido arundinaceae-Bolboschoenetum laticarpi Passarge 1999 corr. Krumbiegel 2006, concentrated in large river floodplains, Bolboschoenetum yagarae Eggler 1933 corr. Hroudova et al. 2009, typical of the littoral zone of fishponds on base-poor bedrocks, and Tripleurospermo inodori-Bolboschoenetum planiculmis Hroudova et al. 2009, occurring mainly in temporarily flooded depressions on arable land. Saline vegetation is dominated by Bolboschoenus maritimus s. str. The alliance Cirsio brachycephali-Bolboschoenion compacti (Passarge 1978) Mucina in Balatova-Tulackova et al. 1993, previously interpreted as vegetation of inland saline marshes, actually relates to freshwater Bolboschoenus vegetation. Therefore a new alliance, Meliloto dentati-Bolboschoenion maritimi Hroudova et al. 2009, is proposed here to include saline reed vegetation of continental areas.

What lies beneath? The pattern and abundance of the subterranean tuber bank of the invasive liana cat's claw creeper, Macfadyena unguis-cati (Bignoniaceae).

Cat’s claw creeper, Macfadyena unguis-cati (L.) Gentry (Bignoniaceae) is a major environmental weed of riparian areas, rainforest communities and remnant natural vegetation in coastal Queensland and New South Wales, Australia. In densely infested areas, it smothers standing vegetation, including large trees, and causes canopy collapse. Quantitative data on the ecology of this invasive vine are generally lacking. The present study examines the underground tuber traits of M. unguis-cati and explores their links with aboveground parameters at five infested sites spanning both riparian and inland vegetation. Tubers were abundant in terms of density (~1000 per m2), although small in size and low in level of interconnectivity. M. unguis-cati also exhibits multiple stems per plant. Of all traits screened, the link between stand (stem density) and tuber density was the most significant and yielded a promising bivariate relationship for the purposes of estimation, prediction and management of what lies beneath the soil surface of a given M. unguis-cati infestation site. The study also suggests that new recruitment is primarily from seeds, not from vegetative propagation as previously thought. The results highlight the need for future biological-control efforts to focus on introducing specialist seed- and pod-feeding insects to reduce seed-output.

Energy flow and nutrient cycling in the Marion Island terrestrial ecosystem: 30 years on

ABSTRACTThis article is a sequel to a word-model description of the ecosystem of sub-Antarctic Marion Island, published in this journal 30 years ago (Smith 1977). It expands on the qualitative considerations of patterns of energy flow and nutrient cycling presented in that paper, by providing quantitative information from subsequent research at the island. Primary production of the island's lowland plant communities is high on an annual basis, because the vegetation has a long growing season due to the lack of severely cold winters or drought. Daily productivity is actually low due to low radiation levels and a cool growing season. The vegetation is particularly efficient regarding its use of nutrients for its growth, but still requires substantial amounts of nutrients to support the high annual production. Seabirds and seals import large quantities of nutrients from the ocean when they breed and moult on the island. They markedly enhance soil and plant nutrient status in the areas in which they occur, and also in adjacent areas. However, by far the greater part of the island's inland vegetation is not directly influenced by birds or seals and most of the nutrients required for plant growth are provided by decomposition of plant litter and peat. Soil invertebrates are crucial facilitators of decomposition processes, which are otherwise restricted by low soil temperatures and high soil moisture contents. Introduced house mice have invaded almost all parts of the island and predate heavily on the invertebrates, thus affecting nutrient mineralisation. This threatens not only the functioning (lowered nutrient availability leading to slower plant growth and the production of a lower quality, more decomposition-recalcitrant plant litter), but also the structure (an altered balance between production and decomposition leads to a change in the relation between peat formation and degradation, which is an important determinant of vegetation succession) of the island's ecosystem. It is suggested that mice may also affect the island's ecology by predating on seabird chicks.

New mangrove ecosystem data along the UAE coast using remote sensing

Characteristics of mangrove communities along the Gulf Coast of the UAE were explored using high-resolution satellite data Terra ASTER imageries in the common visible and near infra-red bands. Mangrove stands in three geographically distinctive sites, Khor Kalba, Khor Umm Al-Quwain and Al Dabbiya, were studied through spatial data and ground verification surveys. Mangroves in the UAE appear in patchy and scattered patterns, occupying about 40 km2 of the coastal zone, half of which are located in Abu Dhabi in sheltered lagoons. The remaining areas are linear communities fringing tidal waterways distributed along intertidal zones. Their distribution is limited however, by aridity and site topography. Despite similarities in substrate conditions, differences in climatic and vegetation characteristics between the three sites indicate that growth conditions seem to be more favourable at Khor Kalba with the higher winter temperatures and higher annual rainfalls. Nine main units were recognized on the colour composite image of the Terra ASTER space data; dense vegetation, scattered vegetation, algal deposits, dry sand, sabkhas, settlements, recent deposits and turbid water, shallow water and deep water. Radiance did not allow for the separation of mangrove areas from inland vegetation through the supervised classification. Confusion was also encountered between different soil classes (e.g. wet soils) and settlements or roads. It is concluded, therefore, that satellite data such as SPOT and Terra ASTER can be effectively analyzed through visual interpretations supported by local digital enhancement.

LINKING MARINE RESOURCES TO ECOTONAL SHIFTS OF WATER UPTAKE BY TERRESTRIAL DUNE VEGETATION

As evidence mounts that sea levels are rising, it becomes increasingly important to understand the role of ocean water within terrestrial ecosystem dynamics. Coastal sand dunes are ecosystems that occur on the interface of land and sea. They are classic ecotones characterized by zonal distribution of vegetation in response to strong gradients of environmental factors from the ocean to the inland. Despite the proximity of the dune ecosystem to the ocean, it is generally assumed that all vegetation utilizes only freshwater and that water sources do not change across the ecotone. Evidence of ocean water uptake by vegetation would redefine the traditional interpretation of plant-water relations in the dune ecosystem and offer new ideas for assessing maritime influences on function and spatial distribution of plants across the dune. The purpose of this study was to identify sources of water (ocean, ground, and rain) taken up by vegetation using isotopic analysis of stem water and to evaluate water uptake patterns at the community level based on the distribution and assemblage of species. Three coastal dune systems located in southern Florida, USA, and the Bahamian bank/platform system were investigated. Plant distributions across the dune were zonal for 61-94% of the 18 most abundant species at each site. Species with their highest frequency on the fore dune (nearest the ocean) indicate ocean water uptake as evidenced by delta 18O values of stem water. In contrast, species most frequent in the back dune show no evidence of ocean water uptake. Analysis of species not grouped by frequency, but instead sampled along a transect from the ocean toward the inland, indicates that individuals from the vegetation assemblage closest to the ocean had a mixed water-harvesting strategy characterized by plants that may utilize ocean, ground-, and/or rainwater. In contrast, the inland vegetation relies mostly on rainwater. Our results show evidence supporting ocean water use by dune vegetation and demonstrate an exciting relationship between seawater and ecotonal shifts in plant function of a terrestrial ecosystem.

Seasonal dynamics of soil microbial biomass in coastal sand dune forest

Sand dunes are a typical landscape in the coast of western Taiwan, where Casuarina forests were established decades ago to stabilize sand dunes and protect the inland vegetation. Study of microbial biomass in such an ecosystem may give insights into the role of microbes in soil fertility and nutrient cycling. We established our study sites in two topographic units based on elevation and drainage types: upland and lowland. The study lasted for 2 years, and soil samples were collected every 3 months. Microbial biomass C (Cmic) and N (Nmic) were high in a shallow humic layer that rested on top of the soil (1222–1319 mg kg−1 for Cmic and 245–276 mg kg−1 for Nmic) and declined sharply to only one-tenth of the above values in the underlying surface soil (0–10 cm depth). Microbial biomass Cmic and Nmic in humic and surface soil were not significantly different between upland and lowland sites. In the upland soils, the mean Cmic was highest in autumn for both the humic and surface soil, and lowest in spring and summer for the humic layer and summer for the surface soil layer. In the lowland soils, the Cmic was highest in winter for both humic and surface soil, and lowest in spring and autumn for the humic layer and spring and summer for surface soil. Strong fluctuations of Cmic and Nmic were associated with the soil moisture prior to sampling, which appeared to control the size of microbial biomass in this environment. Temperature had little effect on the dynamics of soil microbial biomass in the sand dune forest ecosystem.

A Survey of the Strand and Dune Vegetation Along the Pacific and Southern Gulf Coasts of Baja California, Mexico

One hundred and twenty plant species were collected on the dunes along the 1400 km-long western coast of the peninsula of Baja California, Mexico. At sixteen of the thirty-two localities visited, from Tijuana to La Paz, transects were made at right angles to the shore to record cover and zonation of these species. Abronia maritima, a tap-rooted perennial forb, is found along the entire coast and is the major foredune-builder throughout most of its range. The ranges of most of the other species fall into one of three groups corresponding to regions of inland vegetation and to Koppen climatic types of semi-arid (BS) south to 300 N, arid (BW) in the central part, and arid tropical (BSh) south of 240 N. Within each region the vegetation on the dunes immediately above the beach is more uniform than that on the backdunes, where the shrubby vegetation varies according to the degree of surface stabilization. On foredunes, Abronia maritima predominates in the north, in the central sector it is joined by Sesuvium portulacastrum, which has a sirnilar growth habit, and in the Cape region it is replaced as the principal dune-builder by the tropical grasses, Jouvea pilosa and Sporobolus virginicus. These rhizomatous species form flat-topped, continuous dune ridges, in contrast to the individual, conical hillocks built by the tap-rooted forbs to the north. In the arid central sector, salinity of soil water on the fore- dunes increases, and both cover and species-richness decline relative to the values in the northern and southern sectors. Sand grain diameter, which inversely affects rate of burial, is greatest in the Cape region, and may account for the replacement there of A. maritima by grasses. Most species on the foredunes are perennial herbs, whereas a greater diversity of life forms occurs on the back- dunes. Most of the dune species exhibit one of three leaf modifications: succu- lence, canescence, or a hard cuticle. Species having the C4 photosynthetic path- way contribute the majority of the cover in the Cape region, in contrast to the rest of the coast. Dune vegetation on other coasts having similar add to Mediterranean climates is dominated by shrubs on the backdunes and by either grasses (western Australia, Mediterranean Sea) or tap-rooted, perennial forbs

Synecology of Beach Vegetation Along the Pacific Coast of the United States of America: A First Approximation

Thirty-four beaches, located between central Washington and the Mexican border (approximately 47-33? N), were sampled for cover by replicate strip transects, and the results summarized by composite profile diagrams. The zonation patterns of twenty species revealed that the majority could be found in the leading (seaward) edge of vegetation, but most taxa increased in cover with increasing distance from mean tide line; that is, few species exhibited an ecological optimum in the most severe part of the vegetated beach. Even in the most inland portion of the beach plant cover and species richness were typically low (about five species, 2000 cover). Cluster analysis revealed five grouips of stands. The groups were poorly correlated with latitude, except for a major break at 370 N in central California. Regressions showed, as a first approximation, that community composition correlated with factors that reflect protection from disturbance by waves, man, or introduced taxa. Beach vegetation seems less well correlated with macroclimate than inland vegetation. However, the distribution limits of some species did correlate well with macro-climate.

Siwalik microflora from Punjab (India)

The present report ideals with a microfloral analysis of the Middle and Lower Siwalik Formations from the Bhakra-Nangal area of Punjab, India. The microfloral a assemblage which these contain consists of Monoletes, trilobate grains, Triletes, Pinus, pollen grains of Palmae (Arecaceae), Gramineae (Poaceae) and Compositae (Asteraceae), Tetracolpites, etc. During Lower Siwalik times, it is inferred that the vegetation was coastal, subtropical to temperature, while during Middle Siwalik times it changed to a predominantly temperature and inland vegetation. Palmae pollen of the Cocos type, as well as a good representation of pteridophytes, in the Lower Siwalik support this view. There is a rather balanced proportion of angiospermous and gymnospermous elements. During Middle Siwalik times, the gymnosperms were dominant over the angiosperms, and pteridophytes were rather poorly represented. This is suggestive of a gradual cooling of the surroundings and an uplift of the sediments, supporting a temperature coniferous vegetation.