Disturbed Meadows Research Articles

Sedimentary seagrass carbon stock and sources of organic carbon across contrasting seagrass meadows in Indonesia.

Seagrass meadows are an important component of coastal ecosystems globally, and they capture and store organic carbon in living biomass and sediments. Geographical estimates of blue carbon in seagrass habitats are regionally biased, with limited information from the Indo-Pacific region, including Indonesia. Seagrass extent in Indonesia is declining rapidly, and it has been suggested that marine protected areas (MPAs) are an important instrument to support protection of seagrass ecosystems and their services. Thus, this study is aimed at quantifying and comparing sedimentary carbon stocks and sources of organic carbon from seagrass meadows located in undisturbed areas outside MPA, disturbed areas outside MPA, and within MPA in three small islands in Indonesia. The sediment carbon stocks from this study ranged from 19.81 to 117.49 Mg C ha-1, with the highest stock measured inside MPA (77.15 ± 1.38 Mg C ha-1), followed by undisturbed outside MPA (36.08 Mg C ha-1), and the lowest stock at disturbed outside MPA (21.86 ± 0.31 Mg C ha-1). The predominant source of organic carbon in disturbed meadows was from coastal POM (particulate organic matter, ~ 36%), while in MPA and undisturbed sites, the main source was from seagrass, with ~ 38% and ~ 60% contributions, respectively. The results of this study add more data and information on seagrass blue carbon potential from three different islands with different degrees of disturbance in Indonesia.

Сравнительный анализ горно-луговой растительности Южного и Северного Приэльбрусья (Центральный Кавказ) на фоне усиления антропогенной нагрузки

Geobotanical descriptions were carried out on 16 model sites in the upper reaches of the Baksan and Malka rivers along with the southern and northern spurs of mount Elbrus. Despite the differences in species composition and structure of ecological spectra, the reaction of mountain meadow plant communities of regions to increase anthropogenic load is similar. More significant negative changes and higher synanthropization levels of disturbed meadows in the Southern Elbrus region are probably due to the different history of economic development of the two regions.

Highly Disturbed Populations of Seagrass Show Increased Resilience but Lower Genotypic Diversity

The response of seagrass systems to a severe disturbance provides an opportunity to quantify the degree of resilience in different meadows, and subsequently to test whether there is a genetic basis to resilience. We used existing data on levels of long-standing disturbance from poor water quality, and the responses of seagrass (Zostera muelleri) after an extreme flood event in Moreton Bay, Queensland, Australia. Sites were grouped into high and low disturbance categories, in which seagrass showed high and low resilience, respectively, as determined by measuring rates of key feedback processes (nutrient removal, suppression of sediment resuspension, and algal grazing), and physiological and morphological traits. Theoretically, meadows with higher genotypic diversity would be expected to have greater resilience. However, because the more resilient meadows occur in areas historically exposed to high disturbance, the alternative is also possible, that selection will have resulted in a narrower, less diverse subset of genotypes than in less disturbed meadows. Levels of genotypic and genetic diversity (allelic richness) based on 11 microsatellite loci, were positively related (R2 = 0.58). Genotypic diversity was significantly lower at highly disturbed sites (R = 0.49) than at less disturbed sites (R = 0.61). Genotypic diversity also showed a negative trend with two morphological characteristics known to confer resilience on seagrass in Moreton Bay, leaf chlorophyll concentrations and seagrass biomass. Genetic diversity did not differ between disturbed and undisturbed sites. We postulate that the explanation for these results is historical selection for genotypes that confer protection against disturbance, reducing diversity in meadows that contemporarily show greater resilience.

Physical Condition, Sex, and Age-Class of Eastern Red-Backed Salamanders (Plethodon cinereus) in Forested and Open Habitats of West Virginia, USA

Nonforested habitats such as open fields and pastures have been considered unsuitable for desiccation-prone woodland salamanders such as the Eastern Red-backed Salamander (Plethodon cinereus). Recent research has suggested thatPlethodon cinereusmay not only disperse across but also reside within open habitats including fields, meadows, and pastures. However, presence and high densities ofP. cinereuswithin agriculturally disturbed habitats may be misleading if these populations exhibit atypical demographic characteristics or decreased physical condition relative to forest populations. We surveyed artificial cover boards from 2004-2005 to compare physical condition, sex ratios, and age-class structure ofP. cinereusamong woodland, woodland-meadow edge, silvopasture, and meadow sites in the central Appalachian Mountains of southern West Virginia. Physical condition of salamanders was not significantly different among the four habitats. Furthermore, adult sex ratios ofP. cinereustypically were not significantly different from 1 : 1 and were similar between forested and non-forested sites, although populations within silvopastures were biased towards females. However, adult salamanders were significantly more abundant than juveniles in all habitat types, with differences most pronounced within meadow habitats. Our study indicates that relatively small, non-forested habitats such as silvopastures and meadows may not adversely affect the overall physical condition or sex ratios ofPlethodon cinereus. However, the paucity of juveniles within disturbed meadows indicates that these agriculturally modified habitats may negatively impact reproduction or that immature salamanders are at a physiological or competitive disadvantage in comparison to adults, particularly when surface cover is limited.

Effects of temperature and storage length on seed germination and the effects of light conditions on seedling establishment with respect to seed size in Ligularia virgaurea

Abstract Ligularia virgaurea is widely distributed in the alpine meadows of the eastern Qinghai‐Tibet plateau. We studied the effects of temperature and seed storage length on seed germination in a laboratory experiment, the effects of seed mass and light intensity on seed emergence in a pot experiment, and the effect of meadow disturbance intensity on seed emergence in a field experiment. Our results showed that seeds of L. virgaurea germinated well under a wide range of temperatures. Germination percentage decreased with increased seed storage length. When seeds were stored for either 6 or 12 months the germination percentage increased with decreasing temperature. The emergence percentage of large seeds was higher than that of small seeds. Seedling survival of large seeds was greater than that of small seeds in 75% and 50% of natural irradiance. Large seeds of L. virgaurea were more successful colonizers in the alpine meadows. Seeds of L. virgaurea germinated in both disturbed meadows and non‐disturbed meadows, but seed emergence and seedling establishment were higher in the disturbed meadows, that is, disturbance could facilitate the recruitment and establishment of L. virgaurea.

Effects of clam harvesting on sexual reproduction of the seagrass Zostera noltii

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 298:115-122 (2005) - doi:10.3354/meps298115 Effects of clam harvesting on sexual reproduction of the seagrass Zostera noltii Ana Alexandre*, Rui Santos, Ester Serrão Marine Plant Ecology Research Group, CCMAR - Centro de Ciências do Mar, CIMAR - Laboratório Associado, Universidade do Algarve, Gambelas, 8005-139 Faro, Portugal *Email: aalexandre@ualg.pt ABSTRACT: The sexual reproduction of Zostera noltii in the Ria Formosa lagoon (southern Portugal) was assessed by quantifying the variation in both flowering effort and evolution of maturation stages during the fertile season. The effects of clam harvesting on the sexual reproduction of Z. noltii were investigated using both descriptive and experimental approaches. Meadows disturbed by clam harvesting were compared with undisturbed meadows in 2 sectors of the lagoon. In both sectors, disturbed meadows showed significantly lower vegetative shoot density and significantly higher reproductive effort. The reproductive effort in the western disturbed meadows was 2-fold higher than in undisturbed meadows, whereas in eastern disturbed meadows it was 4-fold higher. In disturbed meadows, early maturation stages were found until the end of the flowering season and higher seed production was observed. Both the negative effect of clam harvesting on Z. noltii density and the positive effect on its reproductive effort were confirmed by manipulative field experiments. Plots that were experimentally harvested during the fertile season showed significantly lower vegetative shoot density and higher reproductive effort than unharvested plots. Results suggest that Z. noltii responds to clam harvesting disturbance by both increasing its reproductive effort and extending its fertile season. KEY WORDS: Zostera noltii · Clam harvesting · Sexual reproduction · Maturation scale · Disturbance · Flowering Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 298. Online publication date: August 15, 2005 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2005 Inter-Research.

Populationsdynamik terrestrischer Protozoen (Testaceae, Rhizopoda) in zentralalpinen Lagen Tirols II. Untersuchungen gestörter und relativ ungestörter Böden im Raume Patsch (Tirol, Österreich)

Summary The population dynamics of soil-inhabiting Testacea of 3 experimental plots (1 undisturbed young spruce plot, 2 disturbed meadows) situated in the Tyrolian Centralalps at approximately 1,100 m above sealevel were studied. Maximum abundance, biomass and species numbers are found in the upper 2 cm of all examinated soils, but there is a distinction between undisturbed and disturbed areas: The disturbance of soil by cultivating causes a significant decrease of the number of specimens. While abundance and biomasses decreased with profile depth in the undisturbed soils, there is found a number of specimens in depth b (2–4 cm) which is very similar to that of depth a (0–2 cm) in disturbed areas. The relation disturbed: undisturbed for living Testacea = 1: 6.91 (depth a), 1: 1.45 (depth b), 1: 1.14 (depth c) and this one for empty tests = 1: 3.97 (depth a), 1: 1.30 (depth b), 1: 0.96 (depth c).