Coastal Sandplain Research Articles

Biogeography of Anurans from the Poorly Known and Threatened Coastal Sandplains of Eastern Brazil.

The east coast of Brazil comprises an extensive area inserted in the Tropical Atlantic Domain and is represented by sandy plains of beach ridges commonly known as Restingas. The coastal environments are unique and house a rich amphibian fauna, the geographical distribution patterns of which are incipient. Biogeographical studies can explain the current distributional patterns and provide the identification of natural biogeographical units. These areas are important in elucidating the evolutionary history of the taxa and the areas where they occur. The aim of this study was to seek natural biogeographical units in the Brazilian sandy plains of beach ridges by means of distribution data of amphibians and to test the main predictions of the vicariance model to explain the patterns found. We revised and georeferenced data on the geographical distribution of 63 anuran species. We performed a search for latitudinal distribution patterns along the sandy coastal plains of Brazil using the non-metric multidimensional scaling method (NMDS) and the biotic element analysis to identify natural biogeographical units. The results showed a monotonic variation in anuran species composition along the latitudinal gradient with a break in the clinal pattern from 23°S to 25°S latitude (states of Rio de Janeiro to São Paulo). The major predictions of the vicariance model were corroborated by the detection of four biotic elements with significantly clustered distribution and by the presence of congeneric species distributed in distinct biotic elements. The results support the hypothesis that vicariance could be one of the factors responsible for the distribution patterns of the anuran communities along the sandy coastal plains of eastern Brazil. The results of the clusters are also congruent with the predictions of paleoclimatic models made for the Last Glacial Maximum of the Pleistocene, such as the presence of historical forest refugia and biogeographical patterns already detected for amphibians in the Atlantic Rainforest.

Influence of soil properties on coastal sandplain grassland establishment on former agricultural fields

The decline in species‐rich grasslands across the United States has increased the importance of conservation and restoration efforts to preserve the biodiversity supported by these habitats. Abandoned agricultural fields often provide practical locations for the reestablishment of species‐rich grasslands. However, these fields often retain legacies of agriculture both in their soils, which may have higher pH and nitrogen (N) contents than soils that were never farmed, and in their plant communities, which are dominated by non‐native species and poor in native seed stock. We considered methods of reversing these legacies to create native‐species‐rich grassland on former agricultural land. We tested seeding and tilling combined with additions of sulfur (S), carbon (C), N or water to establish diverse sandplain grassland vegetation on an old field on Martha's Vineyard, Massachusetts. We measured soil pH, extractable nitrate and ammonium, and total and native species richness and native species cover for 5 years after treatment. S additions lowered pH to values typical of never‐tilled sandplain ecosystems and increased native species cover, but had no effect on species richness. C, N, and water additions had no significant effects on the soil or vegetation. Seeding and tilling were more effective at restoring native species richness than any soil amendments and indicated a greater importance of biotic factors compared with soil conditions in promoting sandplain vegetation establishment. S amendment accelerated establishment of native species cover for several years but the effect of S additions compared with seeding and tilling alone declined over time.

Genetic and palaeo-climatic evidence for widespread persistence of the coastal tree species Eucalyptus gomphocephala (Myrtaceae) during the Last Glacial Maximum

Few phylogeographic studies have been undertaken of species confined to narrow, linear coastal systems where past sea level and geomorphological changes may have had a profound effect on species population sizes and distributions. In this study, a phylogeographic analysis was conducted of Eucalyptus gomphocephala (tuart), a tree species restricted to a 400 × 10 km band of coastal sand-plain in south west Australia. Here, there is little known about the response of coastal vegetation to glacial/interglacial climate change, and a test was made as to whether this species was likely to have persisted widely through the Last Glacial Maximum (LGM), or conforms to a post-LGM dispersal model of recovery from few refugia. The genetic structure over the entire range of tuart was assessed using seven nuclear (21 populations; n = 595) and four chloroplast (24 populations; n = 238) microsatellite markers designed for eucalypt species. Correlative palaeodistribution modelling was also conducted based on five climatic variables, within two LGM models. The chloroplast markers generated six haplotypes, which were strongly geographically structured (GST = 0·86 and RST = 0·75). Nuclear microsatellite diversity was high (overall mean HE 0·75) and uniformly distributed (FST = 0·05), with a strong pattern of isolation by distance (r(2) = 0·362, P = 0·001). Distribution models of E. gomphocephala during the LGM showed a wide distribution that extended at least 30 km westward from the current distribution to the palaeo-coastline. The chloroplast and nuclear data suggest wide persistence of E. gomphocephala during the LGM. Palaeodistribution modelling supports the conclusions drawn from genetic data and indicates a widespread westward shift of E. gomphocephala onto the exposed continental shelf during the LGM. This study highlights the importance of the inclusion of complementary, non-genetic data (information on geomorphology and palaeoclimate) to interpret phylogeographic patterns.

The distribution of Long-nosed PotorooPotorous tridactylus tridactylushabitat on the far north coast of New South Wales

The Long-nosed Potoroo Potorous tridactylus tridactylus has declined substantially on the far north coast of New South Wales. In this study, the known and potential habitat of the Long-nosed Potoroo on the coastal sandplain in the region is mapped in detail for the first time. A total of 3,613 ha of potential habitat is distributed in 10 areas from 24 ha to 1,423 ha in size. Heathy Scribbly Gum Eucalyptus signata woodland was considered to be particularly significant habitat in the region. While there is evidence that eight of the areas mapped once supported potoroos, their presence has only been confirmed in four of them since 2000. Targeted survey at known sites where the Long-nosed Potoroo has not been recently confirmed is urgently required, as well as a thorough reassessment of its conservation status in the region. Ecological research into threats and food preferences, and implementation of targeted conservation management actions is also needed.

Recursos vegetais da Restinga de Carapebus, Rio de Janeiro, Brasil

The present paper aimed at identifying the plant resources used in the Restinga de Carapebus, Restinga de Jurubatiba National Park, Rio de Janeiro, Brazil. We carried out 13 one-week visits to the study area and the informants were  nominated by the local population. For each species we present local name, category of use, local uses, and type of plant formation. We identified only one person in the Restinga de Carapebus who knows, uses, and indicates the plants of the coastal sand plains for several purposes. The informant indicated 119 species used, distributed in 100 genera and 49 families, and the most important families in number of species are Myrtaceae (10 species), Clusiaceae and Rubiaceae (both with 6 species). The plants used were classified into the following categories: food, medicine, ornamental, technology, hygiene, fragrance, construction, and firewood. The medicinal usage predominated, with 45 species, among which anti-diarrheic plants presented the highest number of species (10). Most useful species (67) occur in the open Clusia scrub formation. The results presented here are relevant to preserve the cultural use of plant resources in the Restinga de Carapebus.

Influence of extrinsic variables on activity and habitat selection of lowland tapirs ( Tapirus terrestris) in the coastal sand plain shrub, southern Brazil

The objectives of this research were to: 1. evaluate the circadian activity patterns of lowland tapirs ( Tapirus terrestris) throughout the seasons and 2. study the influence of moonlight, temperature and rainfall on the activity patterns and habitat selection of this species, in the coastal sand shrub in southern Brazil. From June 2005 to June 2006, eight tapirs were monitored in a large enclosure containing open and vegetation-covered areas, using four camera traps. Differences in activity patterns within seasons were found. Tapir predominately presented nocturnal-crepuscular activity; however, they differed in the winter, with cathemeral activity patterns. Covered areas were mostly used during periods of extreme temperatures, with less diurnal and more nocturnal activities within these areas, on hotter days. Activity in open areas mainly occurred during periods of intermediate temperatures, both during the day and in the night. Moonlight intensity did not influence nocturnal activities. On days of precipitation of 34 mm or more, there was no record of open-area activities, despite constant activity in covered-area.

NESTING HABITAT RELATIONSHIPS OF SYMPATRIC CRESTED CARACARAS, RED-TAILED HAWKS, ANDWHITE-TAILED HAWKS IN SOUTH TEXAS

We quantified nesting-site habitats for sympatric White-tailed Hawks (Buteo albicaudatus) (n = 40), Red-tailed Hawks (B. jamaicensis) (n = 39), and Crested Caracaras (Caracara cheriway) (n = 24) in the Coastal Sand Plain of south Texas. White-tailed Hawks and Crested Caracara nest sites occurred in savannas, whereas Red-tailed Hawk nest sites occurred in woodlands on the edge of savannas. White-tailed Hawk nest sites were in shrubs and trees that were shorter (3.5 ± 1.0 m) and had smaller canopy diameters (5.5 ± 2.1 m) than those of Red-tailed Hawks (10.1 ± 2.0 m, 13.7 ± 5.8 m) and Crested Caracaras (5.6 ± 1.7 m, 8.5 ± 3.5 m). Red-tailed Hawk nest sites had higher woody densities (15.7 ± 9.6 plants) and more woody cover (84 ± 19%) than those of White-tailed Hawks (5.6 ± 5.8 plants, 20 ± 21%) and Crested Caracaras (9.9 ± 6.7 plants, 55 ± 34%). Crested Caracara nest sites were in dense, multi-branched shrubs composed of more living material (97 ± 3%) than those of White-tailed (88 ± 18%) and Red-tailed hawks (88 ± 18%). Nest sites of White-tailed Hawks, Red-tailed Hawks, and Crested Caracaras were similar to random samples from the surrounding habitat indicating that preferred nesting habitat was available for each of these species at least within 60 m of active nest sites. Nest tree height, along with woody plant and native grass cover best discriminated nest sites among the three raptor species. There was no overlap at Red-tailed and White-tailed hawk nest sites in vegetation structure, while Crested Caracara nests were in habitat intermediate between the two other species. Partitioning of nesting habitat may be how these raptor species co-exist at the broader landscape scale of our study area in the Coastal Sand Plain of Texas.

Historical land use and environmental determinants of nonnative plant distribution in coastal southern New England

The factors that influence the invasion of natural habitats by nonnative plants remain poorly understood. We investigated abiotic, biotic, and human influences on the distribution and abundance of nonnative species in coastal upland habitats of southern New England and adjacent New York, US. We censused vegetation and sampled soils in 776, 20 × 20 m plots in natural areas and constructed a spatially referenced GIS database of the region that included land-use history, distance from roads, and surficial geology. Our results indicate that the modern distribution of nonnative plants is influenced by multiple, interdependent current and historical factors. Glaciolacustrine landforms had greater nonnative species richness and cover than beach-dune, moraine, and glacial outwash sand plain landforms. Extant open-canopied areas (i.e., grasslands, dunes, heather barrens, and old fields) harbored significantly greater nonnative species richness and cover than closed-canopy forests, heathlands, and shrublands. Additionally, soil calcium levels and native species richness were positively associated with nonnative species richness. Sites that were cultivated historically or experienced other soil disturbance had higher nonnative species richness than areas without soil disturbance. Overall, abiotic, biotic and historical land use affected levels of nonnative species richness whereas nonnative cover was largely associated with abiotic conditions, particularly soil characteristics. Because many rare coastal sandplain plants reach their greatest abundance on extant open-canopied habitats, efforts to restore native plants will involve tradeoffs between the benefits of expanded habitat for these species and increased risk of invasion by nonnative species.

Historical influences on the vegetation and soils of the Martha’s Vineyard, Massachusetts coastal sandplain: Implications for conservation and restoration

Both disturbance history and previous land use influence present-day vegetation and soils. These influences can have important implications for conservation of plant communities if former disturbance and land use change species abundances, increase colonization of nonnative plant species or if they alter soil characteristics in ways that make them less suitable for species of conservation interest. We compared the plant species composition, the proportion of native and nonnative plant species, and soil biogeochemical characteristics across seven dominant land use and vegetation cover types on the outwash sandplain of Martha’s Vineyard that differed in previous soil tillage, dominant overstory vegetation and history of recent prescribed fire. The outwash sandplain supports many native plant species adapted to dry, low nutrient conditions and maintenance of native species is a management concern. There was broad overlap in the plant species composition among pine ( Pinus resinosa, P. strobus) plantations on untilled soils, pine plantations on formerly tilled soils, scrub oak ( Quercus ilicifolia) shrublands, tree oak ( Q. velutina, Q. alba) woodlands, burned tree oak woodlands, and sandplain grasslands. All of these land cover categories contained few nonnative species. In contrast, agricultural grasslands had high richness and cover of nonnative plants. Soil characteristics were also similar among all of the woodland, shrubland and grassland land cover categories, but soils in agricultural grasslands had higher pH, extractable Ca 2+ and Mg 2+ in mineral soils and higher rates of net nitrification. The similarity of soils and significant overlap in vegetation across pine plantations, scrub oak shrublands, oak woodlands and sandplain grasslands suggests that the history of land use, current vegetation and soil characteristics do not pose a major barrier to management strategies that would involve conversion among any of these vegetation types. The current presence of high cover of nonnative species and nutrient-enriched soils in agricultural grasslands, however, may pose a barrier to expansion of sandplain grasslands or shrublands on these former agricultural lands if native species are not able to outcompete nonnative species in these anthropogenically-enriched sites.

Plant life history traits of rare versus frequent plant taxa of sandplains: Implications for research and management trials

I apply a comparative, functional group approach to coastal sandplain grassland taxa in order to examine whether rare plant species share certain aspects of rarity and life history characters that are distinct from their more common, co-occurring congeners in these habitats. I compiled a comparative data set containing 16 variables describing biogeographic distributions, level of imperilment, habitat specialization, vegetative versus sexual reproduction, seed dispersal, and dormancy of 27 closely-related pairs of plant species that contrast in their abundance (infrequent versus common) in coastal sandplain grasslands. Frequent and infrequent species were paired within genera (or closely related genera) and thus distributed equivalently across families to control for phylogenetic bias. Paired comparisons revealed that infrequent species were intrinsically rarer range-wide, and exhibited a narrower range and more habitat specialization than their common relatives. A classification tree distinguished infrequent species from common species on the basis of higher habitat specialization, larger seed size, smaller plant height, less reliance less on vegetative (colonial) reproduction, and tendency toward annual or biennial life history. Research and management steps to reduce competition from larger-satured, colonial, perennial species are recommended for these infrequent species. Basic research involving more species and more data on ecophysiological characters, demography, and competitive interactions are needed to identify critical life history traits that will influence responses to particular management regimes.

Establishing Vegetation on Migrating Inland Sand Dunes in Texas

Migration of sand dunes damages range improvements in the Texas Coastal Sand Plain. We determined effects of mulching with native prairie hay and an open weave geotextile fabric, seeding, fertilization, and transplanting on plant species canopy cover on inland sand dunes. We compared applying native hay vs. a synthetic geotextile material to inhibit wind erosion, seeding ‘Alamo’ switchgrass (Panicum virgatum L.), ‘Mason’ sandhill lovegrass (Eragrostis trichodes [Nutt.] Wood), and partridge pea (Chamaecrista fasciculata [Michx.] Greene) vs. no seeding, and fertilization with 468 kg·ha−1 of 45:45:90 (N:P:K) vs. no fertilization. The same treatments were compared in a second experiment except that switchgrass, sandhill lovegrass, vetiver (Vetiveria zizanoides [L.] Nash ex Small), and giant reed (Arundo donax L.) were transplanted rather than seeded. Treatments were applied during March and April 1994 and canopy cover of vegetation in each experimental unit was estimated in October 1994, 1995, and 2004. Livestock were excluded from the study sites. The geotextile fabric degraded within 4 months and was replaced with coastal Bermuda (Cynodon dactylon [L.] Pers.) hay. Fertilization plus native hay mulch resulted in greater (P < 0.05) canopy cover of purple sandgrass (Triplasis purpurea [Walt.] Chapm.), sandbur (Cenchrus incertus M. A. Curtis and C. echinatus L.), and snakecotton (Froelichia spp.) than other treatments in 1994. In 1994 and 1995, canopy cover of switchgrass and sandhill lovegrass was greater (P < 0.05) with a combination of geotextile fabric and commercial hay, seeding, and fertilization than in other treatments. Vegetation composition and canopy cover were similar (P > 0.05) across treatments in 2004 in both experiments. Fertilization, seeding, and transplanting appear unnecessary to establish vegetation on dunes protected from livestock grazing when mulch is applied to inhibit sand movement. El movimiento de dunas de arena perjudica las prácticas de mejoramiento de agostaderos en la región del Texas Coastal Sand Plain. El objetivo del presente estudio fue determinar los efectos del acolchado con heno de pastos nativos y una malla textil además de la fertilización, trasplante, y siembra directa sobre la cobertura aérea de la vegetación en las dunas. Se comparó la malla textil contra el uso de heno para evitar la erosión eólica, la siembra directa de ‘Alamo’ switchgrass (Panicum virgatum L.), ‘Mason’ sandhill lovegrass (Eragrostis trichodes [Nutt.] Wood), y partridge pea (Chamaecrista fasciculata [Michx.] Greene) contra no siembra, y la fertilización con 468 kg·ha−1 de 45:45:90 (N:P:K) contra no fertilización. Los mismos tratamientos se compararon en un segundo experimento con la excepción de que se trasplantaron switchgrass, sandhill lovegrass, vetiver (Vetiveria zizanoides [L.] Nash ex Small), y carrizo (Arundo donax L.) en lugar de sembrados directamente. Los tratamientos se aplicaron en Marzo y Abril de 1994 y la cobertura aérea de la vegetación en cada unidad experimental se estimó en Octubre de 1994, 1995, y 2004. Los sitios se mantuvieron excluidos de pastoreo. La malla textil se degradó en los primeros 4 meses del estudio y se reemplazo con heno de zacate Bermuda (Cynodon dactylon [L.] Pers.). La fertilización en combinación con el acolchado con heno de pastos nativos presentó la cobertura aérea mas alta (P < 0.05) de purple sandgrass (Triplasis purpurea [Walt.] Chapm.), sandbur (Cenchrus incertus M. A. Curtis y C. echinatus L.), y snakecotton (Froelichia spp.) comparado con el resto de los tratamientos en 1994. En 1994 y 1995 la cobertura aérea de switchgrass y sandhill lovegrass fue mas alta (P < 0.05) en la combinación de malla textil, siembra directa, y fertilización comparado con el resto de los tratamientos. La composición de la vegetación y la cobertura aérea fueron similares (P > 0.05) entre tratamientos en 2004 en ambos experimentos. La fertilización, siembra directa, y el trasplante son aparentemente innecesarios para establecer vegetación en las dunas protegidas del pastoreo de ganado cuando se utiliza el acolchado para inhibir el movimiento de las dunas.

A polinização de Krameria bahiana B.B. Simpson (Krameriaceae) por abelhas (Apidae) na restinga, BA

The flowers of K. bahiana mainly produce oil as floral resource for their visitors. Oil collecting bees usually show morphological and behavioral adaptation for their collection. This study focused on the analysis of interactions between the flowers of K. bahiana and their visiting bees, aiming for the efficiency of the pollination, in an area of the Coastal Sand Plains of Bahia State, Brazil. From February/2001 to February/2002 and from May to October/2002 observations were accomplished about the phenology and morphology of the plants and the floral visitors' behavior. The flowers of the inflorescences are zigomorphic, small sized, pink and present a pair of petals modified in epithelial elaiophores, which are responsible for the production of oil. These flowers were visited especially by bees of the genus Centris: C. leprieuri Spinola, C. tarsata Smith, C. trigonoides Lepeletier and C. pulchra Moure, Oliveira & Viana. The bees collected only oil in the flowers, by scratching the elaiophores and then transferring it to scopa located on the tibia and basitarsus of the hind legs. During those actions, the bees often contact the reproductive structures of the flowers, resulting in pollination. C. leprieuri was the most frequent bee during this study, thus considered the effective pollinator. Megachile dentipes Vachal also visited the flowers of K. bahiana, collecting only pollen. However, these bees were considered sporadic pollinators because they were not frequent in the flowers of K. bahiana in the months of observation.

Mechanical Land Clearing to Promote Establishment of Coastal Sandplain Grassland and Shrubland Communities

Abstract The decline in grasslands and other species‐rich early successional habitats on the coastal sandplains of the northeastern United States has spurred management to increase the area of these declining plant communities. We mechanically removed overstory oak and applied seed from a nearby sandplain grassland on the island of Martha’s Vineyard, Massachusetts, to evaluate this technique for creating an open oak community able to support sandplain herbaceous species. We compared vegetation structure and composition before and after clearing in an area of total tree removal (clearcutting), an area where 85% of tree basal area was removed (savanna cutting), and in adjacent coastal oak forest. Plant responses to clearcutting and savanna cutting were similar. Sandplain herbs colonized at high frequencies after seeding and increased herbaceous cover from less than 7% before clearing to 22–38% three growing seasons later. Pennsylvania sedge (Carex pensylvanica) increased in cover approximately 6‐fold, accounting for 84–90% of the increased herbaceous cover. Other native ruderals and exotic herbs reached 2 and less than or equal to 1%, cover, respectively, after three years. Species richness across cleared treatments increased from 30 to 79 species. All forest species were retained. Forest shrubs and trees initially declined from their dominant cover but rebounded after three years. Tree clearing plus seeding appeared to be a viable management practice for increasing cover of herbaceous sandplain species while causing minimal increases in exotic herbaceous cover. The long‐term persistence of sandplain herbs may require periodic disturbances that limit woody regrowth.

Evolución de la playa de Sa Riera (Cap de Begur, Costa Brava) en los últimos 50 años

En las últimas décadas la regulación de los caudales fluviales mediante la construcción de presas y esclusas junto con la modificación antrópica de la línea de costa ha provocado una alteración de la dinámica litoral que se ha manifestado principalmente en los tramos de costa baja. Antiguas costas de acumulación han pasado a ser actualmente zonas hajo el predominio de los procesos erosivos o en el mejor de los casos a mantener el equilibrio en el balance sedimentario. En este marco general de penuria sedimentaria de las costas bajas la playa de Sa Riera se distingue por estar sujeta a una dinámica litoral de signo opuesto ya que en las últimas cinco décadas ha experimentado una acreción generalizada. Mediante la utilización de fotografías aéreas y su tratamiento en un sistema de información geográfica (SIG), se han podido establecer la tasa y el ritmo de progradación de la playa, estimándose en 46 metros el avance máximo sufrido por la línea de costa en estos cincuenta años. También se ha podido comprobar como dicha acreción es percibida por un determinado perfil de usuario de playa como un impacto desfavorable para sus actividades en el litoral.

Direct and indirect effects of salt spray and fire on coastal heathland plant physiology and community composition

Coastal sandplain heathlands are managed largely by prescribed burning. While it is known that salt spray is an important natural disturbance contributing to the maintenance of coastal heathlands, it is unclear whether fire in coastal areas intensifies the detrimental effects of salt spray on plants growing close to the ocean. We carried out a field experiment to test the interactive effects of fire and salt spray on Martha's Vineyard, Massachusetts. Following a prescribed fire, one-meter-square plots were established in burned and unburned areas and randomly assigned a control or salt spray treatment. After ten weeks of spray treatments we found that burning stimulated new growth and salt spray consistently increased plant water stress, increased leaf necrosis, and inhibited shoot elongation. Burning did not increase the negative effects of salt spray in individual plants; salt spray and control treated plants growing in burned areas showed less water stress and leaf necrosis than those in unburned areas. This may be due to increased water availability in the burned area resulting from lower biomass and therefore lower competition for water and lower evapotranspiration rates. Burning reduced plant canopy height, decreased vascular plant species richness, and stimulated new growth in plants. Our results suggest that fire indirectly reduces the damaging effects of salt spray by increasing soil water availability and decreasing plant water stress.

Salt spray and edaphic factors maintain dwarf stature and community composition in coastal sandplain heathlands

North American coastal sandplain heathlands are unique in species composition and vegetation, but the extent to which edaphic factors influence the structure of these communities is currently debated. It was hypothesized that salt spray and edaphic factors maintain the dwarf stature and community composition of heathlands by limiting plant growth and excluding competitively dominant woody species close to the ocean. Field surveys were carried out to investigate the spatial patterns of salt spray accumulation, soil salt and soil moisture. High salt spray correlated significantly with increased leaf necrosis and water stress in Myrica pensylvanica and with decreased plant height. Plant community composition changed across a salt spray and soil gradient, as well. Distinctive sub-communities were identified that separated according to soil salt and soil moisture but salt spray was the main factor affecting sites occupied only by heathland vegetation. Results from this study suggest that salt spray suppresses the growth of heathland plants in close proximity to the ocean, and therefore maintains the low stature in these dwarf shrublands. This research also demonstrates that the physical environment influences the community structure in heathlands, particularly by limiting tree species from growing in high salt spray, low water availability sites.

Establishing Vegetation on Migrating Inland Sand Dunes in Texas

Migration of sand dunes damages range improvements in the Texas Coastal Sand Plain. We determined effects of mulching with native prairie hay and an open weave geotextile fabric, seeding, fertilization, and transplanting on plant species canopy cover on inland sand dunes. We compared applying native hay vs. a synthetic geotextile material to inhibit wind erosion, seeding ‘Alamo’ switchgrass (Panicum virgatum L.), ‘Mason’ sandhill lovegrass (Eragrostis trichodes [Nutt.] Wood), and partridge pea (Chamaecrista fasciculata [Michx.] Greene) vs. no seeding, and fertilization with 468 kg ha-1 of 45:45:90 (N:P:K) vs. no fertilization. The same treatments were compared in a second experiment except that switchgrass, sandhill lovegrass, vetiver (Vetiveria zizanoides [L.] Nash ex Small), and giant reed (Arundo donax L.) were transplanted rather than seeded. Treatments were applied during March and April 1994 and canopy cover of vegetation in each experimental unit was estimated in October 1994, 1995, and 2004. Livestock were excluded from the study sites. The geotextile fabric degraded within 4 months and was replaced with coastal Bermuda (Cynodon dactylon [L.] Pers.) hay. Fertilization plus native hay mulch resulted in greater (P &lt; 0.05) canopy cover of purple sandgrass (Triplasis purpurea [Walt.] Chapm.), sandbur (Cenchrus incertus M. A. Curtis and C. echinatus L.), and snakecotton (Froelichia spp.) than other treatments in 1994. In 1994 and 1995, canopy cover of switchgrass and sandhill lovegrass was greater (P &lt; 0.05) with a combination of geotextile fabric and commercial hay, seeding, and fertilization than in other treatments. Vegetation composition and canopy cover were similar (P &gt; 0.05) across treatments in 2004 in both experiments. Fertilization, seeding, and transplanting appear unnecessary to establish vegetation on dunes protected from livestock grazing when mulch is applied to inhibit sand movement.

The coastal roadside vegetation and environmental gradients in the arid lands of Egypt

A recent floristic and environmental survey was undertaken on the roadside verges along the main highway between El Arish and Rafah (31° 10’N, 33° 48’E and 31° 17’N, 34° 15’E) that extend for about 45 km on the northeastern Mediterranean coast of Sinai (Egypt). 63 stands were studied at 700-m intervals to represent the variation of vegetation, and to compile the floristic composition of the study area. Four main landform zones were distinguished (from the seashore inwards) and run parallel to the roadway: (A) coastal plain, (B) saline depressions, (C) sand plains and (D) sand dunes. There is a gradual increase in the total number of recorded species in the recognized landform units. Application of TWINSPAN analysis yielded 18 vegetation groups (VG) that comprised 7 main vegetation types (VT). These vegetation types were (I) Artemisia monosperma in the sand dunes, (II) Artemisia monosperma-Echinops spinosus in the sand plains, coastal plain and sand dunes, (III) Cyperus capitatus-Ammophila arenaria in the sand dunes, (IV) Ammophila arenaria-Pancratium maritimum in the coastal plain, (V) Zygophyllum album, (VI) Arthrocnemum macrostachyum and (VII) Arthrocnemum macrostachyum-Zygophyllum album in the saline depressions. Ordination techniques of Detrended Correspondence Analysis (DCA) and Canonical Correspondence Analysis (CCA) were used to examine the relationship between the roadside vegetation and the 8 studied environmental variables: total soluble salts (TSS), pH, calcium carbonate (CaCO3), sand, fine fractions (silt and clay), distance from the seashore (DFS), landform units (LF) and altitude (Alt). Both ordination techniques indicated that soil salinity, calcareous sediments, soil texture, landform, altitude and distance from seashore were the most important factors for the distribution of the vegetation pattern along the road verges in the study area. These gradients were related closely to the first three CCA axes, and accounted for 72.4% of the species relationship among the stands. Low species richness in the vegetation types of the coastal plain and saline depressions may be related to their high soil salinity, while the high species diversity and the highest share of alien weeds of vegetation types characterized the sand dunes may be related to the high disturbance of their substrates as a result of agriculture practising, farming processes and other excessive human disturbances.

The Effects of Livestock Grazing and Recreation on Irish Machair Grassland Vegetation

Machair grassland uniquely occurs over sandy, calcareous soils of coastal sand-plains in dune systems of north-western Scotland and Ireland. This study assesses the plant species composition of Irish machair grassland at a landscape-scale. Machair sites were sampled with quadrats and multivariate analysis was used to assess relationships between species abundance, soil physical variables, livestock grazing and recreation activity. Grazing by cattle and sheep was recorded at most sites, with recreation activities at nearly half the sites. Detrended and Canonical Correspondence Analysis ordinations showed that the main gradients of community composition were related to the key variables of soil calcium carbonate content, soil organic matter content, livestock grazing intensity and recreation pressure. Partial Canonical Correspondence Analysis showed that livestock grazing intensity and recreation pressure explained about twice as much variation as the key soil variables and that rabbit grazing had a much smaller but significant effect. Livestock grazing and recreation activities were shown to be ecologically damaging in terms of having a larger area of bare sand and a lower species diversity. Bare sand can increase the risk of storm damage and reduce habitat heterogeneity by sand-plain deflation. Controls on livestock density, the length of the grazing season and recreation activities are proposed, which we suggest would facilitate vegetation recovery. We highlight the need for local planning authorities, who control coastal development in Ireland, to include agricultural management prescriptions in their machair site management plans.

Grapevine productivity and yield components: A case study using field vines of Zante currant

Yield components of the parthenocarpic cultivar Zante were analysed for five vineyards of diverse age and management. The data was obtained as part of an experiment to improve fruit set and yield by applying combinations of gibberellin and 2-chloroethyltrimethyl ammonium chloride or 4-chlorophenoxyacetic acid. Four of the vineyards were located in the Brockman valley north of Perth, Western Australia, two of these were irrigated, one was rain fed and one received supplementary flood irrigation. The fifth lay in an adjacent area of coastal sand plain, at the foot of the Darling scarp, and was irrigated. The vines were aged from 6 to 50 years. Principal component analysis showed that vine age was negatively correlated with vigour (pruning weight) and with berry number per bunch. Vine age however was not strongly related to either yield or yield components (bunch number and berry volume). Sugar concentration was negatively correlated with all yield components but imprecisely modelled based on any combination of the measured variables. Berry number per vine appeared to be the underlying factor determining 'sink' strength though this was inextricably confounded with bunch number per vine. Interpretation of the data leads to the conclusion that increased berry volume is an inefficient means of increasing dried yield. This conclusion argues for caution in the application of plant growth regulators that act primarily to increase berry volume. Yield of sugar per vine was accurately modelled based on second order relationships with bunch number per vine, berry number per bunch, berry volume and pruning weight. Vine age also showed a second order relationship to yield although the range was relatively small. The observations are considered in terms of developing strategies for maximising dried yield and devising mathematical models to account for photoassimilate (dry matter) partitioning in Vitis.