Grass Habitats Research Articles

Effects of fungal endophyte infection on soil properties and microbial communities in the host grass habitat

Effects of fungal endophyte infection on soil properties and microbial communities in the host grass habitat

마이크로네시아 축 환초내 잘피밭의 어류 종조성

The fish species composition of seagrass bed in Chuuk Lagoon, Micronesia, was investigated every month from August 2009 to July 2011, using a seine net for fish caught. A total of 32 fish species belonging to 18 families under 6 orders were identified during the study period. Of these fish, Atherinomrus lacunosus, and Strongylura incise were the major dominant species representing 85.0% in total number of individuals. The number of species and individuals were high from August to December 2009, 2010. The biomass was highest in September 2010 and the diversity index was higher in September 2009, April, August 2010 and July 2011. The 14 dominant species could be divided into 2 groups of 3 individuals based on appearance patterns; (1) resident species and temporal species (9 species, e.g. Atherinomrus lacunosus), juvenile and adults living in seagrass beds and juveniles living only in seagrass beds; (2) temporal species (2 species, e.g. Hemiramphus lutkei), juveniles living only in seagrass beds; (3) temporal species (3 individuals, e.g. Caranx sexfasiatus). For some species, the appearance patterns were affected by water temperature. However, the relationships between sea currents, salinity, tide, and structure of fish assemblage remain unclear. Further studies that regularly monitor sea grass habitats are necessary to clearly understand the correlation between environmental factors and sea grass habitat use patterns in fish assemblages.

Seasonal Distribution of Ticks in Four Habitats near the Demilitarized Zone, Gyeonggi-do (Province), Republic of Korea

This study describes the seasonal distribution of larvae, nymph, and adult life stages for 3 species of ixodid ticks collected by tick drag and sweep methods from various habitats in the Republic of Korea (ROK). Grasses less than 0.5 m in height, including herbaceous and crawling vegetation, and deciduous, conifer, and mixed forests with abundant leaf/needle litter were surveyed at United States (US) and ROK operated military training sites and privately owned lands near the demilitarized zone from April-October, 2004 and 2005. Haemaphysalis longicornis Neumann adults and nymphs were more frequently collected from April-August, while those of Haemaphysalis flava Neumann and Ixodes nipponensis Kitaoka and Saito were collected more frequently from April-July and again during October. H. longicornis was the most frequently collected tick in grass habitats (98.9%), while H. flava was more frequently collected in deciduous (60.2%) and conifer (57.4%) forest habitats. While more H. flava (54.1%) were collected in mixed forest habitats than H. longicornis (35.2%), the differences were not significant. I. nipponensis was more frequently collected from conifer (mean 8.8) compared to deciduous (3.2) and mixed (2.4) forests.

Comparison of Dragging and Sweeping Methods for Collecting Ticks and Determining Their Seasonal Distributions for Various Habitats, Gyeonggi Province, Republic of Korea

As part of the 65th Medical Brigade tick-borne disease surveillance program to determine the abundance, geographical and seasonal distributions, and tick-borne pathogens present in the Republic of Korea, dragging and sweeping methods were compared to determine their efficiency for collecting ticks in grass and deciduous, conifer, and mixed forest habitats at military training sites and privately owned lands in northern Gyeonggi Province near the demilitarized zone from April-October, 2004-2005. Three species of Ixodid ticks, Haemaphysalis longicornis, Haemaphysalis flava, and Ixodes nipponensis, were collected. Overall, H. longicornis adults and nymphs were most frequently collected from grass and deciduous forest habitats, accounting for 98.2 and 66.2%, respectively, of all ticks collected. H. flava adults and nymphs were most frequently collected from conifer and mixed forests, accounting for 81.6, and 77.8%, respectively, of all ticks collected. I. nipponensis adults and nymphs accounted for 9.3% of all ticks collected from mixed forests, were less commonly collected from deciduous (4.1%) and conifer (4.1%) forests, and infrequently collected from grass habitats (0.9%). Overall, there were no significant differences between dragging and sweeping methods for the three species when the areas sampled were similar (sweeping = 2 x the area over the same transect). Adults and nymphs of H. longicornis were most commonly collected from April-August, while those of H. flava and I. nipponensis were most commonly collected during April-July and again during October. Larvae of all three species were most frequently observed from July-September.

Soil moisture correlates with shrub–grass association in the Chihuahuan Desert

Abstract The current ongoing expansion of shrubs at the expense of grasses in the Chihuahuan Desert is largely believed to result from a shift in competition between shrubs and grasses. Both groups, shrubs and grasses, occupy a gently sloping silty (loessial) soil within the Jornada Experimental Range (JER), northern Chihuahuan Desert, NM, USA. At the sites dominated by tarbush (Flourensia cernua), the shrubs seem to be randomly distributed in between barren surfaces, surfaces covered by biocrusts, and dense stands of burrograss (Scleropogon brevifolius), which are mainly confined to 2–4 m diameter and 0.02–0.1 m deep depressions. Often, the shrubs are accompanied by a dense stand of tobosa grass (Pleuraphis mutica) that occupies the under-canopy. In order to study shrub–grass interactions, four habitats were defined: playa habitats with bare silty material (PL), habitats with mature biocrust (CR), habitats with burrograss mainly confined to depressions (DP) and tarbush shrubs with a dense population of tobosa grass under the shrub canopy (UC). Periodic moisture measurements at the 0–30 cm soil and potential evaporation took place during the summers of 1999 and 2009. In addition, the grass biomass in these habitats was monitored. Moisture content and grass biomass followed the pattern PL DP > UC. The findings point to a close link between grass biomass and the soil moisture content, with the high grass biomass at DP explained by runoff contribution, while that of UC by the higher moisture content mainly attributed to the reduced evaporation under shading conditions. The co-existence of shrubs and under-canopy grass does not support the notion of high competition between both groups of plants. It may rather indicate facilitation. The close link between soil moisture content and the grass habitats also suggests that lower water availability during summertime may explain current grass scarcity in JER.

环境和扩散对草地群落构建的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 环境和扩散对草地群落构建的影响 DOI: 10.5846/stxb201204180559 作者: 作者单位: 陕西师范大学 生命科学学院 陕西 西安 710062,陕西师范大学 生命科学学院 陕西 西安 710062,陕西师范大学 生命科学学院 陕西 西安 710062,陕西师范大学 生命科学学院 陕西 西安 710062,陕西师范大学 生命科学学院 陕西 西安 710062,陕西师范大学 生命科学学院 陕西 西安 710062 作者简介: 通讯作者: 中图分类号: 基金项目: 陕西师范大学优秀科技预研项目(201002001) Effect of species dispersal and environmental factors on species assemblages in grassland communities Author: Affiliation: College of Life Science, Shaanxi Normal University, Xi'' an 710062 Shaanxi, China,College of Life Science, Shaanxi Normal University, Xi'' an 710062 Shaanxi, China,,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:植物群落构建机制是生态学研究的热点之一。长久以来这个难题并没有得到很好的解释,且争议较多。生态位理论或中性理论,或是二者的共同作用,这样的结论在不同的研究中都有印证。以黄土高原子午岭地区的草地群落为例,对3种不同的草地群落(5a的弃耕地、阴坡和阳坡的草地)进行了野外群落学调查,采用Mantel test和主轴邻距法(PCNM)分析方法,研究了空间地理距离和环境资源差异对于草本植物群落分布的影响,结果表明:地理距离和环境差异共同解释了群落组成相似性的79.3%,剔除环境因子的影响,地理距离解释了群落组成相似性的33.8%;而剔除地理距离的影响,环境因子解释了群落组成相似性的14.2%。无论是生态位理论还是中性理论,其在黄土高原草本群落构建过程中都有作用,但中性理论扮演了更为重要的角色。 Abstract:The construction mechanisms of plant communities are a hot topic in the field of ecology. However, the question of how communities are constructed has not yet been adequately explained. Whether these mechanisms are driven by niche theory, neutral theory, or a combination of the two has been confirmed in a variety of research studies; most of them concentrated on the study of tropical rain forests. So we looket at grassland communities on China's Loess Plateau as example, hoping to provide some grounds for answering this question in this paper. Three different grass habitats were selected: land which had been abandoned for five years, north-facing slopes and south-facing slopes. The Mantel test analysis was applied to test the correlation between similarity in community composition, geographic distance and environment distance. The result of our research suggested that geographic distance has a significant effect on the community composition (P<0.01); there is a correlation between environment distance and community composition (P<0.01), but the function of environment distance is not as good as geographic distance. In order to further explore the influence, PCNM analysis was used to test for fitness: the percentage of community assembly can be explained in terms of the geographic distance and environmental distance. The results indicate the distribution of plants are highly variable and more strongly related to geographical distance rather than to environmental differences. Together, geographical distance and environmental distance explained 79.3% of the variation in floristic similarity. Pure geographic distance or pure environmental distance alone explained 33.8% and 14.2% of the variation in floristic similarity, respectively. The neutral theory plays a strong role in the species assemblages within ecological communities, but the function of the niche can't be ignored. 参考文献 相似文献 引证文献

Effect of forest and field habitat features on abundance of genera in nematode assemblages

Abundances of nematode genera were examined in several forest and field habitats located in close proximity in Florida, USA. Effects of selected habitat features were also evaluated, such as tree type, management and presence of litter, grasses or invasive species. Of 37 common taxa evaluated, ten were more abundant in forest and ten in field habitats. Several genera includingAcrobeloides,AphelenchoidesandMesocriconemawere common in all habitats. Light management, consisting of mowing of grasses, negatively affected 19 taxa. More genera appeared adapted to closed forest over open forest, and most of these were more common in plots with oak trees or oak litter than in plots with pine. Numbers ofParatylenchus,PlectusandXiphinemawere further increased by the presence of herbaceous plants on the forest floor. When invasive elephantgrass (Pennisetum purpureum) was included in plots with other grasses, numbers of eight genera that typically were common in grass plots were further increased.Alaimus,CervidellusandWilsonemawere negatively affected by the invasive elephantgrass. Most of the nine genera in guild Ba2 were more abundant in either forest (Acrobeles,Cervidellus,Plectus,Wilsonema) or grass (Eucephalobus,Zeldia) habitats, whileAcrobeloideswas common and two genera were rare in all habitats. The effects of habitats and habitat features on many different nematode taxa add to our growing knowledge of the ecological habits of free-living nematodes.

Factors affecting the migrating waterfowls at the Annaiwilndawa Ramsar site of the northwestern Sri Lanka

Factors affecting the migrating waterfowls at three reservoirs of the Annaiwilundawa Ramsar site of Northwestern Sri Lanka were studied from October 2009 to March 2012. Populations of the waterfowls were recorded in each month using line transacts method. The day was divided in to three time periods as morning (7:00 hrs - 10:00 hrs), afternoon (12:00 hrs – 14.00 hrs) and evening (15:00 hrs - 17:00 hrs) and the diurnal activities were recorded using “Focal animal sampling method” and the “Scan sampling method”. Any event causing the waterfowls to alter their behavior was recorded as a disturbance. Waterfowl were observed through a 15~60 x 25 spotting scope and 25 x 45 binocular. Garganey (Anas querquedula) was the only migratory waterfowl recorded. The number of Garganey gradually declined in number over the three year period with maximum in December 2009 (335 individuals and density 3350 birds / Km2). From November 2009 to February 2010 (winter season) average population of Garganey was 3188 Birds/ Km2, from November 2010 to February 2011 it was 1358 Birds/ Km2 and from November 2011 to February 2012 it was 760 Birds/ Km2. Gargeney abandoned the Annaiwilundawa Ramsar site when the reservoirs dried up in January and February 2012. Garganey (n = 3098) allocated most of their time for resting (morning 41%, mid day 55% and evening 35%). This was followed by preening (morning 33%, mid day 37% and evening 22%). ANOVA results revealed no significant differences in the diurnal activity budgets of Garganey during the three time periods of the study. (Sleeping F(2,28) )= 0.186, p = 0.831 Resting F(2,28) = 1.480, p= 0.254, Feeding, F(2,28)= 2.783, p = 0.079, Flying F(2,28)= 0.111, p= 0.896, Swimming F(2,28)= 3.172, p= 0.057, walking F(2,28) = 2.059, p= 0.146, Preening F(2,28) = 0.124, p= 0.884, Agnostic F(2,28)= 0.458, p= 0.637,Alert F(2,28) = 0.363, p= 0.699, Bathing F(2,28)= 1.307, p= 0.287). Grass habitat (86%) was heavily used by Garganey for their diurnal activities followed by open water (9%). Habitat utilization of Garganey did not differ significantly during the study period (Invasive plant water hyacinth F(2,21) = 1.566, p = 0.232, Salvinia F(2,21) = 0.681, p = 0.517 Olu F(2,21) =0.385, p = 0.685, Open water F(2,21) = 1.390, p = 0.271, Grass F(2,21) = 0.894, p = 0.424, muddy Ground F(2,21) = 0.901, p = 0.421). Garganey was heavily disturbed by Brahminy kite.

Population stability of a tree-galling aphid, Baizongia pistaciae, at three spatial scales

AbstractThe population stability of Baizongia pistaciae (Linnaeus) (Hemiptera: Aphididae) on its primary host, the tree Pistacia palaestina Boissier (Anachardiaceae), was investigated using 17–20 years of data from a study of gall abundance on individual trees in Israel. Abundance varied by at least an order of magnitude among adjacent trees, among locations, and among years. Stability was quantified for the alternate-year cohorts as population variability (PV) and persistence, at three spatial scales. PV (a proportion between 0 and 1) was similar between cohorts and declined with population scale – subpopulation (a tree): 0.676 ± 0.092 (±1 SD, n = 40); population: 0.581 ± 0.098 (±1 SD, n = 6); region: 0.424 (0.345 and 0.503, n = 2). Persistence (proportion of years that galls were present) was usually near 0.9, but 0.1 for some subpopulations, and 1.0 at the population and regional scales. Although protected within large galls on long-lived trees, the PV of B. pistaciae was similar to that of native, free-living aphid species on more ephemeral herbaceous hosts, but lower than for introduced aphid species. Persistence of B. pistaciae decreased as abundance decreased but not as PV increased. PV did not increase with the length of the study period; and declined with increasing population scale, because abundance was not synchronised among subpopulations or populations. PV was similar among populations, suggesting this parameter is characteristic of the species, although positive correlations between cohorts on a tree showed that PV was affected by the site-specific tree–grass habitats in which this species lives.

Release site manipulation to favour European ground squirrel Spermophilus citellus translocations: translocation and habitat manipulation

Translocating European ground squirrels Spermophilus citellus has become a popular conservation tool. However, few release techniques have been carefully evaluated. To contribute to an evidence‐based ground squirrel translocation guide for wildlife managers, we evaluated conditions of habitat manipulation (grass height and artificial burrow entrance angle) which we expected to affect settlement of translocated ground squirrels during the critical period after release. In a field experiment, we translocated 173 individuals in southeastern Hungary in 2007. We released the animals into angled or vertical artificial burrows and manipulated grass height. We found that animals preferred angled (∼ 30°) artificial burrows, which facilitate digging, and medium‐height grass (18 cm ± 1.5). Moreover, although ground squirrels generally are associated with short grass habitats, overhead protection by grasses is valuable after a translocation. This result implies that in order to accomplish a translocation, it is not sufficient to only know the habitat preference of a species in undisturbed situations, but also how and to what extent habitat characteristics should be manipulated to increase the chances of success.

Multi-scale habitat occupancy of invasive lionfish (Pterois volitans) in coral reef environments of Roatan, Honduras

The Indo-Pacific lionfish species [Pterois volitans (Linnaeus, 1758) and P. miles (Bennett, 1828): Family Scorpaenidae] are the first nonnative marine fishes to establish in the Western North Atlantic and Caribbean Sea. Despite the continued documentation of its range expansion and highly publicized invasion (including public-driven removal efforts) there remains a paucity of basic information on lionfish ecology. This knowledge gap limits effective long-term management. In this study we conducted a multi-scale investigation of habitat occupancy of a newly established population of lionfish in Roatan, Honduras. Based on field surveys and citizen sightings in Roatan Marine Park we found that lionfish occurred more frequently on aggregate coral reef habitats (54% of sightings) compared to patch reef habitats (30%) and sea grass lagoons (16%). In general, these aggregate and patch reef habitats contained adults (mean total length =118.9 mm and 114.7mm, respectively) whereas sea grass habitats contained juveniles (mean total length=89.5 mm). At the micro-habitat scale lionfish occupied areas dominated by hard coral and overhanging structure; the same microhabitats containing native fishes of concern – grouper (Nassau grouper, Epinephelus striatus; yellow fin grouper, Mycteroperca venenosa) and snapper (dog snapper, Lutjanus jocu; mutton snapper, Lutjanus analis). Results from this study contribute information on basic habitat requirements of lionfish and inform current management removal efforts focused on containing spread and mitigating their impacts on native species.

Behavioural ecology of four-horned antelope ( Tetracerus quadricornis de Blainville, 1816) in the tropical forests of southern India

Four-horned antelope is one of the smallest Asian bovids, endemic to India and Nepal. Despite its wide distribution in India, the species has received very little scientific attention. We studied its habitat preference, activity budget, diet, social behaviour and breeding in Mudumalai Wildlife Sanctuary. Among tropical dry deciduous and thorn forests, where the species is distributed, higher abundance was observed in dry deciduous areas (0.26 individuals/km, 95% CI = 0.22–0.29) especially the short grass habitat associated with stunted and sparse tree growth known as ‘tree-savanna’ than the dry thorn forest (0.09 individuals/km, CI = 0.001–0.18). The antelopes follow a bimodal feeding pattern with 52% morning (06:00–10:00 h) and 65% evening (14:00–18:00 h) devoted to feeding. Diet was studied by analyzing 59 pellets collected from two major habitat types during the dry season. Of the 52% of the diet components identified, grass (28.6%, 14 species) and browse biomass (23.3%, 10 species; with five herbs (9.6%), one shrub (5.6%) and leaves and fruits from four trees (8.2%)) constituted equal parts indicating a mixed feeder category. Mean group size of 1.5 (±0.71 SD range: 1–4) individuals estimated from 94 direct sightings with solitary individuals (62%) and adult with fawn/s (11%) constituting over 70% of the sightings indicating a non-herding nature of the species. Newborns were sighted from February to May with a peak during April and the reported gestation period of c. 8 months suggests mating taking place during June–August. Mean litter size was 1.6 (±0.53 SD, n = 9). The study suggests the need for including dry thorn forest habitats of Sigur plateau in the existing protected areas and detailed studies for long-term conservation of the species in this region.

Variation of within-day foraging costs in the striped mouse (Rhabdomys pumilio)

Foraging behavior is influenced by spatial and temporal habitat heterogeniety. Here we report on within-day foraging and perceived risk of predation by the striped mouse (Rhabdomys pumilio) in a grassland savannah with wooded “islands” using giving-up densities (GUD, amount of food left behind in depletable food patches). Higher GUDs correspond to higher forging costs. GUDs were measured six times per day at 2-h intervals from paired stations along fern–grass habitat boundaries at 3 and 6m distances from 10 wooded islands. R. pumilio's GUDs varied significantly over the course of the day with highest GUDs during the afternoon hours of 1–3 pm, and lowest between 7 and 9 am in the morning. The same pattern was consistent for both habitats (fern and grass) and distances from the wooded islands. GUDs decreased with distance from the woody islands in both fern and grass habitats and were significantly lower in the fern habitat. This activity pattern suggests that R. pumilio responds to a spectrum of spatially and temporally varying risks from a variety of predators including aerial predators that increase risk as they make use of mid-day thermals.

Increased grazing and dominance of an exotic pasture (Bothriochloa pertusa) affects vertebrate fauna species composition, abundance and habitat in savanna woodland

The invasion of exotic pasture species into intact woodlands has the potential to affect native fauna by altering habitat structure and ecosystem function. The spread of these weeds is generally in concert with cattle grazing, so that fauna or habitat change is due to multiple interrelated causes. In this study we investigated whether the spread of the introduced pasture grass Bothriochloa pertusa and replacement of the native bluegrass B. ewartiana in eucalypt woodlands of northern Queensland has had an effect on terrestrial vertebrate fauna. We located 40 sites that sampled a range of native and introduced pastures cover, and investigated the spatial pattern of abundance with canonical analysis of principle coordinates, and correlation of the habitat attributes on the ordination space. We then selected a subset of four habitat attributes (eliminating highly colinear variables) and modelled species response to each using an information-theoretic approach. Thirty-one species (26 birds, one mammal and four reptiles) and two summary variables (bird abundance and richness) had best subset Akaike Information Criteria models with reliable parameters estimates. Seventeen models contained the B. pertusa frequency term and a further 16 had a term relating to upper storey cover (tree cover &gt;10, 5–10 or 3–5 m). Though pasture grass cover, grazing and habitat features were correlated and thus we cannot ascribe B. pertusa as the sole determinant of fauna species change, this study has demonstrated that tropical savanna woodlands with changing Bothriochloa dominance from native to introduced species have different fauna species composition. In particular bird species richness, ground nesting species (e.g. rufous songlark Cincloramphus mathewsi, golden-headed cisticola Cisticola exilis) and terrestrial reptiles (e.g. Carlia munda and Ctenotus taeniolatus) declined. Disturbance-tolerant species such as Australian magpie Cracticus tibicen and yellow-throated miners Manorina flavigula increased in abundance in exotic pasture-dominated sites. As pastoral intensification continues in northern Australian rangelands there is a potential for significant change in the relative abundance and composition of vertebrate fauna and the reduction or loss of some species in the landscape.

Broad-Scale Relations between Conservation Reserve Program and Grassland Birds: Do Cover Type, Configuration and Contract Age Matter?~!2010-03-03~!2010-06-20~!2010-08-07~!

The Conservation Reserve Program (CRP) is a voluntary cropland set-aside program where environmentally- sensitive cropland is retired to a conservation practice. Grassland birds should benefit because most CRP is grass habitat and because amount of land in CRP is highest in agriculture-dominated areas of the United States where grassland habitat has been most impacted. We used the Breeding Bird Survey and Common Land Unit (CLU) data (spatially-explicit data of farm field boundaries and land cover) to identify relations between types and configurations of CRP and grassland bird abundance in 3 Midwestern states. All 13 species we studied were related to at least one aspect of CRP habitat - specific conservation practices (e.g., native vs. exotic grass), CRP habitat configuration, or habitat age. Treating all types of CRP as a single habitat type would have obscured bird-CRP relations. Based on our results, creating a mosaic of large and small set-aside patches could benefit both area-sensitive and edge-associated grassland birds. Additionally, northern bobwhite and other birds that use early successional grasslands would benefit from periodic disturbances. CRP, agri- environment schemes, and other government-sponsored set-aside programs may be most successful when administered as part of a targeted, regional conservation plan.

Crustacea of the Cayman Islands, British West Indies II. Heteromysis (Olivemysis) ebanksae, a new species (Mysida: Mysidae) from Little Cayman and Grand Cayman Islands

ABSTRACT During a survey of the marine Crustacea of the Cayman Islands, Heteromysis ebanksae, new species was discovered in depths of 1–3 m adjacent to Little Cayman Island and from North Sound, Grand Cayman Island. The new species, which belongs to the subgenus Olivemysis Bacescu, 1968, collected from live bottom and sea grass habitats, is distinguished from other closely related species in the western Atlantic by differences in the setation of thoracic endopod 3, male pleopod 4 and the telson. Heteromysis ebanksae has 2–9 flagellated spiniform setae on male pleopod 4, 6–10 spinules along the anterior half of the telsonic cleft, and each apical lobe of the telson has a pair of spiniform setae, the outer 1.2 times longer than the inner. A diagnostic table separating the new species from H. actinae Clarke, 1955, H. bermudensis G. O. Sars, 1885 and H. floridensis Brattegard, 1969 is presented.

Rapid Assessment of Risks to a Mobile Marine Mammal in an Ecosystem‐Scale Marine Protected Area

Ecosystem-scale networks of marine protected areas (MPAs) are important conservation tools, but their effectiveness is difficult to quantify in a time frame appropriate to species conservation because of uncertainties in the data available. The dugong (Dugong dugon) is a mobile marine species that occurs in shallow inshore waters of an ecosystem-scale network of MPAs (the Great Barrier Reef World Heritage Area [GBRWHA]). We developed a rapid approach to assess risk to dugongs in the region and evaluate options to ameliorate that risk. We used expert opinion and a Delphi technique to identify and rank 5 human factors with the potential to adversely affect dugongs and their sea grass habitats: netting, indigenous hunting, trawling, vessel traffic, and poor-quality terrestrial runoff. We then quantified and compared the distribution of these factors with a spatially explicit model of dugong distribution. We estimated that approximately 96% of habitat of high conservation value for dugongs in the GBRWHA is at low risk from human activities. Using a sensitivity analysis, we found that to decrease risk, commercial netting or indigenous hunting had to be reduced in remote areas and the effects of vessel traffic, terrestrial runoff, and commercial netting had to be reduced in urban areas. This approach enabled us to compare and rank risks so as to identify the most severe risks and locate specific sites that require further management attention.

UVB sensitivity and cyclobutane pyrimidine dimer ( CPD) photolyase genotypes in cultivated and wild rice species

We investigated the UVB-sensitivity in 12 rice strains belonging to two cultivated species (O. sativa and O. glaberrima) and three wild species (O. barthii, O. meridionalis and O. rufipogon) of rice possessing the AA genome, while focusing on the CPD photolyase activity and the genotypes of CPD photolyase. Although the UVB sensitivity, CPD photolyase activity, and CPD photolyase genotype varied widely among these rice species, the sensitivity to UVB radiation depended on the activity of the CPD photolyase, regardless of grass shape, habitat, or species. The rice strains examined here clearly divided into three groups based on the CPD photolyase activity, and the activity of the strains greatly depended on amino acid residues at positions 126 and 296, with the exception of the W1299 strain (O. meridionalis). The amino acid residues 126 and 296 of CPD photolyase in Sasanishiki strain (O. sativa), which showed higher enzymatic activity and more resistance to UVB, were glutamine (Gln) and Gln, respectively. An amino acid change at position 126 from Gln to arginine ("Nori"-type) in the photolyase led to a reduction of enzymatic activity. Additionally, an amino acid change at position 296 from Gln to histidine led to a further reduction in activity. The activity of the W1299 strain, which possesses a "Nori"-type CPD photolyase, was the highest among the strains examined here, and was similar to that of the Sasanishiki. The CPD photolyase of the W1299 contains ten amino acid substitutions, compared to Sasanishiki. The alterations in amino acid residues in the W1299 CPD photolyase compensated for the reduction in activity caused by the amino acid substitutions at positions 126. Knowledge of the activity of different CPD photolyase genotypes will be useful in developing improved rice cultivars.

Habitat Condition and Associated Macrofauna Reflect Differences Between Protected and Exposed Seagrass Landscapes

Seagrass landscape configurations associated with different physical settings can affect habitat-structure and plant-animal relationships. We compared shoal grass (Halodule wrightii) habitat and macrofaunal variables between two fragmented seagrass landscapes at barrier-island locations subject to different disturbance regimes. Five seagrass habitat variables including above ground biomass (AGB), shoot number, per shoot biomass, epiphyte biomass and below ground biomass (BGB), differed significantly between the island landscapes. Per shoot biomass and epiphyte biomass also varied significantly over the seagrass growing season; and epiphyte biomass showed a strong landscape-time interaction. Abundances of microgastropods normalized to AGB differed significantly between landscapes. An inverse relationship between the abundance of microgastropods and epiphyte loading suggests a possible functional link. However, additional temporal mismatch between epiphyte loading and microgastropod abun- dance indicates that controls on epiphyte loading were complex. Seagrass habitat was more fragmented within the Cat Island (CI) landscape. Wind direction and strength imply that the CI landscape experienced more physical distur- bance than the Horn Island (HI) landscape. This study highlights some potential links involving landscape configura - tion, habitat structure, and macrofaunal associations which can be further addressed using hypothesis-driven research.

Vegetation of Külső-Somogy in Hungary II : Regional diversity and pattern of non-woody habitats at landscape scale

In this study occurrence, proportion and landscape pattern of grasslands and wastelands are analysed in Külső-Somogy based on MÉTA method at landscape scale. The relative importance of these habitat types represent more than the half of the total number of non-woody habitats listed for Hungary. Wastelands (62%) and disturbed grasslands (54%) have relatively the greatest area in this region, where uncharacteristic dry or semi-dry grasslands and tall herb communities dominate. Semi-natural dry and semi-dry grassland habitat types are in subordinated position in the southern and eastern parts of the region, especially with habitats of E-group, H-group or uncharacteristic herb communities (OC). As semi-natural non-woody wet grasslands types habitats of B-group are the relatively most frequent with eu- and mesotrophic reed and Typha beds, nontussock beds of large sedges and mosaics of marsh communities of channels, ditches and artificial lakes. In landscape elements which are poor in grasslands uncharacteristic wet or dry grass habitats (O-group) are significant. The north-western parts of Külső-Somogy near Lake Balaton are strongly endangered by the reduction or lack of semi-natural grasslands. Regional land and grassland management ought to promote functioning of grassland regeneration processes.