Response of seagrass indicators to shifts in environmental stressors: A global review and management synthesis

Although seagrass-based indicators are widely used to assess coastal ecosystem status, there is little universality in their application. Matching the plethora of available indicators to specific management objectives requires a detailed knowledge of their species-specific sensitivities and their response time to environmental stressors. We conducted an extensive survey of experimental studies to determine the sensitivity and response time of seagrass indicators to ecosystem degradation and recovery. We identified seagrass size and indicator type (i.e. level of biological organization of the measure) as the main factors affecting indicator sensitivity and response time to degradation and recovery. While structural and demographic parameters (e.g. shoot density, biomass) show a high and unspecific sensitivity, biochemical/physiological indicators present more stressor-specific responses and are the most sensitive detecting early phases of environmental improvement. Based on these results we present a simple decision tree to assist ecosystem managers to match adequate and reliable indicators to specific management goals.     

Characteristics of surface-water flows in the ridge and slough landscape of Everglades National Park: implications for particulate transport

Over the last one hundred years, compartmentalization and water management activities have reduced water flow to the ridge and slough landscape of the Everglades. As a result, the once corrugated landscape has become topographically and vegetationally uniform. The focus of this study was to quantify variation in surface flow in the ridge and slough landscape and to relate flow conditions to particulate transport and deposition. Over the 2002–2003 and 2003–2004 wet seasons, surface velocities and particulate accumulation were measured in upper Shark River Slough in Everglades National Park. Landscape characteristics such as elevation, plant density and biomass also were examined to determine their impact on flow characteristics and material transport. The results of this study demonstrate that the release of water during the wet season not only increases water levels, but also increased flow speeds and particulate transport and availability. Further, flow speeds were positively and significantly correlated with water level thereby enhancing particulate transport in sloughs relative to ridges especially during peak flow periods. Our results also indicate that the distribution of biomass in the water column, including floating plants and periphyton, affects velocity magnitude and shape of vertical profiles, especially in the sloughs where Utricularia spp. and periphyton mats are more abundant. Plot clearing experiments suggest that the presence of surface periphyton and Utricularia exert greater control over flow characteristics than the identity (i.e., sawgrass or spike rush) or density of emergent macrophytes, two parameters frequently incorporated into models describing flow through vegetated canopies. Based on these results, we suggest that future modeling efforts must take the presence of floating biomass, such as Utricularia, and presence of periphyton into consideration when describing particulate transport.     

Using soil profiles of seeds and molecular markers as proxies for sawgrass and wet prairie slough vegetation in Shark Slough, Everglades National Park

We measured the abundance of Cladium jamaicense (Crantz) seeds and three biomarkers in freshwater marsh soils in Shark River Slough (SRS), Everglades National Park (ENP) to determine the degree to which these paleoecological proxies reflect spatial and temporal variation in vegetation. We found that C. jamaicense seeds and the biomarkers Paq, total lignin phenols (TLP) and kaurenes analyzed from surface soils were all significantly correlated with extant aboveground C. jamaicense biomass quantified along a vegetation gradient from a C. jamaicense to a wet prairie/slough (WPS) community. Our results also suggest that these individual proxies may reflect vegetation over different spatial scales: Paq and kaurenes correlated most strongly (R ² = 0.88 and 0.99, respectively) with vegetation within 1 m of a soil sample, while seeds and TLP reflected vegetation 0–20 m upstream of soil samples. These differences in the spatial scale depicted by the different proxies may be complementary in understanding aspects of historic landscape patterning. Soil profiles of short (25 cm) cores showed that downcore variation in C. jamaicense seeds was highly correlated with two of the three biomarkers (Paq, R ² = 0.84, p<0.005; TLP, R ² = 0.97, p<0.0001), and all four of the proxies indicated a recent increase in C. jamaicense biomass at the site. Using a preliminary depth-to-age relationship based on matching charcoal peaks with available ENP fire records (1980-present) specific to our coring site, we found that peak-depths in C. jamaicense seed concentration appeared to correspond to recent minimum water levels (e.g., 1989 and 2001), and low seed abundance corresponded to high water levels (e.g., 1995), consistent with the known autecology of C. jamaicense. In summary, the combination of C. jamaicense seeds and biomarkers may be useful for paleoecological reconstruction of vegetation change and ultimately in guaging the success of ongoing efforts to restore historic hydrologic conditions in the South Florida Everglades.     

小麦种子在不同保存条件下的生活力丧失特性研究

近年来种子在低温种质库和室温保存条件下的生活力丧失特性研究日益受到关注,但是与其重要性相比,目前很少见有文献报道此方面进展。本文中我们监测了在中期库、室温和人工加速老化条件下小麦种子的生活力变化,以了解种子在这些保存条件下的生活力变化特性。结果表明,三种条件下所有种子的存活曲线均呈反S形,这种特点不受保存条件的影响。随着保存温度的降低,种子生活力丧失速度降低,反S形曲线的平台期和种子寿命延长。我们采用T检验来判断平台期和种子生活力快速下降期之间的转折点（Pt）,发现小麦种子在不同条件下保存时,其Pt均十分接近,在82.2%到83.6%之间。本文讨论了将Pt以及其他生理指标作为种子保存过程中生活力快速下降的预警指标的可能性。     

2.5D Morphogenesis: modeling landuse and landcover dynamics in the Ecuadorian Amazon

The Ecuadorian Amazon, lying in the headwaters of the Napo and Aguarico River valleys, is experiencing rapid change in Land Use and Land Cover (LULC) conditions and regional landscape diversity uniquely tied to the spontaneous agricultural colonization of the Oriente region of northeastern Ecuador beginning in the mid to late 1970s. Spontaneous colonization occurred on squattered lands located adjacent to oil company roads and in government development sectors composed of multiple 50 ha land parcels organized into `piano key' shaped family farms or fincas. Portions of these fincas were deforested for agricultural extensification depending upon the age of the finca and several site and situation factors. Because fincas are managed at the household level as spatially discrete, temporally independent units, land conversion at the finca-level is recognized as the chief proximate cause of deforestation within the region.Focusing on the spatial and temporal dynamics of deforestation, agricultural extensification, and plant succession at the finca-level, and urbanization at the community-level, a cell-based morphogenetic model of Land Use and Land Cover Change (LULCC) was developed as the foundation for a predictive model of regional LULCC dynamics and landscape diversity. Here, LULC characteristics are determined using a time-series of remotely sensed data (i.e., Landsat Thematic Mapper (TM) and Multispectral Scanner (MSS)) using an experimental [semi-traditional] (hybrid unsupervised-supervised) classification scheme resulting in a time-series data set including LULC images for 1973, 1986, 1989, 1996, and 1999. Pixel histories of LULC type across the time-series were integrated into LULC trajectories and converted into seed or input data sets for LULC modeling to alternate time periods and for model validation. LULC simulations, achieved through cellular automata (CA) methodologies, were run on an annual basis to the year 2010 using 1973 as the initial conditions and the satellite time-series as the `check points' in the simulations. The model was developed using the Imagine Spatial Modeler of the ERDAS image processing software, and enhanced using the Spatial Modeler Language (SML). The model works by (a) simulating the present by extrapolating from the past using the image time-series, (b) validating the simulations via the remotely sensed time-series of past conditions and through field observations of current conditions, (c) allowing the model to iterate to the year 2010, and (d) comparing model outputs to an autoregressive time-series approach for annual conditions that are compared via paired t-tests of pattern metrics run at the landscape-level to define compositional and structural differences between successive model outputs.     

山东省冬小麦干热风灾害预警模型研究

以30年的气象和产量数据为研究对象,对冬小麦成熟收获前16天的23个温度指标、23个空气相对湿度指标和16个风速指标与相对气象产量进行统计分析.通过相关分析确定不同生态区的干热风灾害风险因子,对不同生态区的风险因子和相对气象产量进行回归分析,构建冬小麦干热风灾害风险预警模型.结果表明:同类气象因子在不同生态区中的作用表现不同,模型因素构成以因子的互作为主,单因子的直接影响作用不突出.鲁西北和鲁中是干热风灾害的高危险区,鲁西南干热风灾害的危险最小.     

Sensitivity of landscape measurements to changing grain size for fine-scale design and management

Landscape pattern quantities are affected by issues of scale, namely extent and resolution. The grain size (resolution) of fine-resolution geographic information system (GIS) data for two highly fragmented landscapes in USA and Italy were altered to evaluate the effect of grain size changes on landscape pattern metrics and cost-surface model outputs. Beginning with 3 m resolution data and resampling the data to 300 m resolution, we applied pattern metrics and cost-surface models (available in GIS software) and evaluated the types of behaviors in resulting quantities. Results showed that some pattern metrics are robust to changes in grain size (such as area, cohesion, interspersion and juxtaposition metrics), while others exhibit staircase-like or erratic responses. Compared to previous studies, we identified behavioral responses that differ from grain-size changes at coarser resolutions. Cost-surface models demonstrated robust or consistent responses to grain size changes in most cases. For both types of pattern measurement, however, we found that behaviors could differ contextually; that is, there could be different types of behaviors for different landscapes, classifications, or grain sizes. Results indicate that comparing spatial data collected at different scales (such as historical data to more recent, high-resolution sensed data) is complicated by different types of responses to changes in grain size. This may limit the applicability of tools for the measurement of landscape change over time if landscapes are represented by differently scaled data.     

Sawgrass (Cladium jamaicense) responses as early indicators of low-level phosphorus enrichment in the Florida Everglades

Anthropogenic phosphorus (P) inputs to the Florida Everglades have produced dramatic changes in the wetland vegetation of this otherwise oligotrophic system. While the proliferation of undesirable plant species in response to enrichment has been well documented, nutrient-related changes in the physiological and morphological attributes of existing vegetation, prior to any shifts in species composition or changes in the spatial extent of certain taxa, have yet to be adequately characterized. In this experiment, three sawgrass-dominated areas were enriched with P for 3 years at rates of 0.4 g P/m²/year (HP), 0.1 g P/m²/year (LP), or 0 g P/m²/year (controls) to assess potential impacts of P-enriched discharges from stormwater treatment areas into the Everglades. Elevated concentrations of TP in rhizomes and leaves and reduced ratios of leaf N:P were detected in HP plants within ~1 year at most sites. Live leaf densities, plant heights, and plant densities of the HP groups were generally higher than LP and control groups after 2 years, a pattern that was evident even after major fire events. Total aboveground biomass was significantly elevated in both HP and LP treatments at two of the three sites after 3 years. No change in species composition was detected during the study. Planned hydrologic restoration measures will increase P loads into parts of the Everglades that have not previously experienced anthropogenic P enrichment. Monitoring native vegetation such as sawgrass can be a sensitive and relatively robust means of detecting unintended P enrichment in these areas prior to shifts in vegetation community composition or changes in area cover of key species.     

Selecting biological indicators for monitoring soils: A framework for balancing scientific and technical opinion to assist policy development

Soils are one of the most important features of the natural capital of terrestrial ecosystems. There is a strong and increasing policy requirement for effective monitoring of soils at local, regional and national-scales. However, it remains unclear which properties of soils are most appropriately monitored. This is partly due to the wide range of goods and services that soils provide, but also their inherent chemical, physical and biological complexity. Given that the biota plays such fundamental roles in the majority of ecosystem services provided by soils, biological properties are logical candidates as effective indicators, to complement soil physico-chemical properties. A plethora of biological methods have been suggested as indicators for monitoring soils but few are used in national-scale monitoring or are published as international standards. A framework for selecting ecologically relevant biological indicators of soil quality, for national-scale soil monitoring, that cover the range of functions and services of soil was devised. The literature was surveyed to identify 183 candidate biological indicators which were then scored by experts and stakeholders against a wide range of scientific and technical criteria. The framework used the scores and weightings to then rank, prioritise and select the indicators. This semi-objective approach using a “logical sieve” allowed repeated iterations to take account of end-user requirements and expert opinion. A ranked list of 21 indicators was produced that covered a range of genotypic-, phenotypic- and functional-based indicators for different trophic groups. Four of these were not deemed sufficiently robust for ready deployment in a national-scale monitoring scheme without further methodological development. The suite of indicators identified offers the strongest potential candidates for deployment in national-scale soil monitoring schemes. However, standard operating procedures, their inherent sensitivity, ability to discriminate between soil:land use combinations, ecological interpretation all need to be confirmed. The power of the approach adopted here is that it provides a clear record and audit trail on the decision-making process, enables different priorities to be set contingent on the nature of the desired monitoring, and can direct and allow the inclusion of further methods or indicators into the framework.     

Evaluation of Golestan Province’s Early Warning System for flash floods,Iran, 2006–7

Golestan province located in NE Iran is well known for deadly flash floods. This study aimed to evaluate the region’s Early Warning System (EWS) for flash floods. We used an adapted version of the questionnaire developed by the United Nations International Strategy for Disaster Reduction. We reviewed documents on the EWS of Golestan, and conducted a qualitative study comprising interviews with experts and affected people in Kalaleh and Minoodasht. Results were discussed by an expert panel. Regarding risk knowledge, there was a hazard map at Provincial Disaster Taskforce (PDT) drawn by the provincial Office for Water Resource Management, but no risk analysis was available. Local people were aware of their exposure to flooding, but not aware of the existence of a hazard map and their vulnerability situation. In terms of monitoring and warning, PDT faced serious limitations in issuing Early Warnings, including (1) an inability to make point predictions of rainfall, and (2) the absence of a warning threshold. Dissemination and communication issued by the Meteorological Office followed a top-to-bottom direction. The contents were neither clearly understood by other institutions nor reached the potential recipients within an appropriate time frame. There was a need for a comprehensive response plan with adequate exercises, and no evaluation framework existed. Golestan EWS is in dire need of improvement. To fill in the gaps ensuring local people receive timely warning, we propose a community-based model called "Village Disaster Taskforce" (VDT) in which individual villages act as operational units, but interlinked with other villages and PDT.     

生物预警系统探讨

本文运用系统工程观点给出生物预警系统概念,并给出一些应用例子。     

Effects of ultrasound on DNA and RNA synthesis in preimplantation mouse embryos.

Ultrasound is used extensively to monitor the growth of ovarian follicles in in vitro fertilization and embryo transfer (IVF-ET) programs, as well as to follow the progress of early pregnancy. There have been scattered reports in the literature that exposure to ultrasound may have an adverse effect on reproduction in the rat (Bologne et al: CR Soc Biol 177:381-387, 1983; Demoulin et al: Ann NY Acad Sci 442:146-152, 1985), and also in humans (Demoulin et al: Ann NY Acad Sci 442: 146-152, 1985). We report here that diagnostic levels of pulsed ultrasound did not affect either the number of embryos produced, or the ability to incorporate labelled precursors into DNA and RNA, respectively. Measurements of temperature elevation of ovaries exposed to ultrasound showed that neither controls nor experimental tissue exhibited temperature elevation greater than 1 degree C.     

5. SOME NOTES RESULTING FROM A HOLIDAY TRIP THROUGH EAST GRIQUALAND

The study investigated the bird species diversity associated with vegetation communities found on a single mountain slope in the Usuthu Gorge Community Conservation Area, northern KwaZulu-Natal. Thirteen sample sites were surveyed on a monthly basis for 12 months. Over this period, 279 birds and 55 species were recorded, of which the Dark-capped Bulbul Pycnonotus tricolor was the most abundant. The Rattling Cisticola Cisticola chiniana was the indicator species in the highest community, Open Bushveld, which is characterised by grassland and bush patches. The White-bellied Sunbird Cinnyris talatala was an indicator in the second-lowest community, Dense Bushveld–Woodland, which is characterised by steep slopes and thickets. In Wooded Grassland, located between the above two communities, the highest beta diversity (species turnover) was recorded and this outcome was probably caused by large areas covered by rocks that compelled woodland birds to move through this community. Contrary to expectation, the gamma diversity per vegetation community increased with elevation from 18 to 33 species in Dense Bushveld–Woodland, Wooded Grassland and Open Bushveld. A future study should measure bird species diversity on larger elevational gradients, i.e. slopes from 500 to 3 000 m above sea level, which also include more distinct vegetation communities.     

How does forest landscape structure explain tree species richness in a Mediterranean context?

Although the strong relationship between vegetation and climatic factors is widely accepted, other landscape composition and configuration characteristics could be significantly related with vegetation diversity patterns at different scales. Variation partitioning was conducted in order to analyse to what degree forest landscape structure, compared to other spatial and environmental factors, explained forest tree species richness in 278 UTM 10 × 10 km cells in the Mediterranean region of Catalonia (NE Spain). Tree species richness variation was decomposed through linear regression into three groups of explanatory variables: forest landscape (composition and configuration), environmental (topography and climate) and spatial variables. Additionally, the forest landscape characteristics which significantly contributed to explain richness variation were identified through a multiple regression model. About 60% of tree species richness variation was explained by the whole set of variables, while their joint effects explained nearly 28%. Forest landscape variables were those with a greater pure explanatory power for tree species richness (about 15% of total variation), much larger than the pure effect of environmental or spatial variables (about 2% each). Forest canopy cover, forest area and land cover diversity were the most significant composition variables in the regression model. Landscape configuration metrics had a minor effect on forest tree species richness, with the exception of some shape complexity indices, as indicators of land use intensity and edge effects. Our results highlight the importance of considering the forest landscape structure in order to understand the distribution of vegetation diversity in strongly human-modified regions like the Mediterranean.     

Dynamics of soil organic carbon and soil fertility affected by alfalfa productivity in a semiarid agro-ecosystem

We explore the dynamics of soil organic carbon of various forms and its relation with soil fertility in seeded alfalfa grassland established using a field micro-catchment technique to harvest water on the semiarid Loess Plateau in China. Five regimes were set up: (1) conventional flat cultivation without mulch (CK), (2) ridges and furrows were set up alternately on flat land, with 15 cm between each so that the distance between successive ridges (or successive furrows) was 30 cm, and the ridges were mulched with plastic film (M30), (3) similar to M30, but with twice the distance between furrows and ridges (M60), (4) similar to M30, but the ridges were not mulched (B30), (5) similar to M60, but the ridges were not mulched (B60). The increase in alfalfa forage yield in the mulch regimes promotes soil organic carbon (SOC) content, the light fraction of organic carbon (LFOC), the heavy fraction of organic carbon (HFOC) and microbial biomass carbon (MBC). MBC was significantly higher in M30 and M60 than in the other regimes. Significant positive correlation is found between MBC and LFOC (R=0.89; P<0.0001), and MBC and HFOC (R=0.82; P=0.00016). At the end of our three-year experiment, the C/N ratio of 10.09 in M60 was significantly (P<0.005) higher than the other regimes. Since a lower C/N ratio accelerates SOC decomposition in this region, the higher C/N ratio in M60 could limit mineralization of soil nitrogen, conserving soil nitrogen and SOC. The lower ratio of nitrate and nitrite nitrogen to total nitrogen, of 10.74, in M60 at the end of this experiment than in the other regimes and before sowing supports this point. The correlations of SOC with available P and with the ratio of available P to total P are positive in the dry year of 2001, but negative in the wet year of 2002. This can be explained on the basis that a high forage yield of alfalfa requires more soil available P in the wet years than in the dry years.     

Effects of sampling and sub-sampling variation using the STAR-AQEM sampling protocol on the precision of macroinvertebrate metrics

As part of the extensive field sampling programme within the European Union STAR project, replicate macroinvertebrate samples were taken using the STAR-AQEM sampling method at each of 2–13 sites of varying ecological quality within each of 15 stream types spread over 12 countries throughout Europe. The STAR-AQEM method requires the sub-sampling and taxonomic identification of at least one-sixth of the sample and at least 700 individuals. Replicate sub-samples were also taken at most of these sites. Sub-sampling effects caused more than 50% of the overall variance between replicate samples values for 12 of the 27 macroinvertebrate metrics analysed and was generally greatest for metrics that depend on the number of taxa present. The sampling precision of each metric was estimated by the overall replicate sampling variance as a percentage P_samp of the total variance in metric values within a stream type. Average over all stream types, the three Saprobic indices had the lowest percentage sampling variances with median values of only 3–6%. Most of the metrics had typical replicate sampling variances of 8–18% of the total variability within a stream type; this gives rise to estimated rates of mis-classifying sites to ecological status class of between 22 and 55% with an average of about 40%. This suggests that the precision of such metrics based on the STAR-AQEM method is only sufficient to indicate gross changes in the ecological status of sites, but there will be considerable uncertainty in the assignment of sites to adjacent status classes. These estimates can be used to provide information on the effects of STAR-AQEM sampling variation on the expected uncertainty in multi-metric assessments of the ecological status of sites in the same or similar stream types, where only one sample has been taken at a point in time and thus there is no replication.     

\"Official\" and \"practical\" kin: Inferring social and community structure from dental phenotype at Neolithic Çatalhöyük, Turkey

The Neolithic site of Çatalhöyük, Turkey (7400–5600 cal BC) is widely acknowledged for its role in the study of early farming communities. To better understand the social and community structure of this setting, an intracemetery biological distance analysis was conducted. Metric and nonmetric observations were recorded in both deciduous and permanent dentitions (n = 266) to explore phenotypic patterning of individuals interred within individual buildings. Specifically, this study tests the hypothesis that individuals within houses and house groupings represent family units and the social structure of Çatalhöyük was largely biological‐kin based. Multivariate and univariate statistical procedures were applied to phenotypic dental data. Results indicate that inclusion for interment within a house was only minimally related to biological affinity. Moreover, the site does not appear to be organized into larger, biologically related neighborhoods of houses. These findings suggest that Çatalhöyük may not have been a kin‐based society, largely because membership within a house cemetery was not solely defined on the basis of biological affinity, such as in a family group. Rather, it appears that social structure was centered on the house as the unifying social principle. The choice for interment location may have transcended biological lines thereby creating an alternate and more fluid definition of “kin.” These findings can be used to understand the transition to settled life and biological patterning in this Neolithic community. Am J Phys Anthropol 2011. © 2011 Wiley‐Liss, Inc.