Specific Vegetation Types Research Articles

Forest maturity has a stronger influence on the prevalence of spider monkeys than howler monkeys in an anthropogenically impacted rainforest landscape

The transformation and depletion of primary forest over the past few decades have placed almost half of the world’s primate species under the threat of extinction. Developing any successful conservation program for primates requires distribution and demography data, as well as an understanding of the relationships between these factors and their habitat. Between March and June 2010 and 2011 we collected data on the presence and demographic parameters of howler and spider monkeys by carrying out surveys, and validated our findings using local knowledge. We then examined the relationship between forest type and the presence of these primates at 54 sites in the northern area of the Selva Zoque Corridor, Mexico. We detected 86 spider monkey groups across 31 plots and censused 391 individuals (mean ± SD = 5.9 ± 3.0 individuals per sub-group, n = 67 sub-groups). We also detected 69 howler monkey groups across 30 plots and censused 117 individuals (mean ± SD = 5.3 ± 2.4 individuals per group, n = 22 groups). Howler monkey presence was not related to any specific vegetation type, while spider monkeys were present in areas with a higher percentage of tall forest (trees > 25 m high). Overall, spider monkeys were more prevalent than howler monkeys in our sampling sites and showed demographic characteristics similar to those in better protected areas, suggesting that the landscape features in the Uxpanapa Valley are suitable for their needs. Conversely, howler monkey presence was found to be more limited than in other regions, possibly due to the extended presence of spider monkeys.

Antelope Jackrabbit (Lepus alleni) Habitat Characteristics in a Former Rangeland

Semi-desert grasslands in the southwestern United States have undergone significant ecological changes as a result of anthropogenic activities beginning in the 1800s. As efforts to restore semi-desert grasslands continue, importance should be placed on understanding the habitat requirements of species, and their relationships with other plants and animals. We examined habitat characteristics of antelope jackrabbits (Lepus alleni Mearns 1890) at Buenos Aires National Wildlife Refuge in south-central Arizona. We examined antelope jackrabbit habitat in relation to endangered Pima pineapple cacti (Coryphantha scheeri Kuntz var. robustispina Schott) and available freshwater sources. Dominant vegetation type and cover were measured at 247 points in antelope jackrabbit home ranges between October 2015 and December 2015. Additionally, we documented the proximity of antelope jackrabbit locations to Pima pineapple cacti and available water sources to determine whether antelope jackrabbits have a spatial relationship with this endangered cactus or water availability.Antelope jackrabbits did not select for habitat based on the vegetation characteristics we measured, proximity to Pima pineapple cacti or based on water availability (P > 0.05).Some jackrabbit species have indicated habitat structure preferences, and while antelope jackrabbits are most commonly associated with tropic-subtropic savannas, our study did not show that antelope jackrabbits select for specific vegetation types or a specific vegetation density, nor native grasses over non-native grasses. Antelope jackrabbits may encounter and eat Pima pineapple cactus opportunistically, as opposed to selecting habitat where Pima pineapple cactus occur. Additionally, antelope jackrabbits did not choose habitat based on the location of freshwater sources which may be because they do not need to drink water to survive and instead get their water needs from their food. Little information exists on how antelope jackrabbits select habitat. This study concluded that there is no relation between vegetation factors previously thought to influence antelope jackrabbit habitat selection and habitat use. Future studies based on larger-scale variables, like topography or predator pressure, may help in understanding the factors that influence how this species uses man-altered landscapes.

Ecological Characterization ofSyzygium(Myrtaceae) in Papua New Guinea

Syzygium is the largest woody genus of flowering plants in the world and one of the most important components of the forest vegetation in Papua New Guinea (PNG). Although the systematics of the genus is improving, a comprehensive appraisal of the environmental features and gradients of its species is still lacking. Our work aims to fill this gap by analyzing the georeferenced specimens collected at the Lae National Herbarium of PNG. A data set of 1,563 records of 131 species was used to assess their altitudinal gradients and the correspondence with the main vegetation types and to model their spatial ecological niche with respect to climatic, topographical, and pedological variables. Several species were found to be widely distributed throughout the region, while other species were restricted to narrow altitudinal belts or only occurred in specific vegetation types. Overall, the genus is also characterized by an increasing altitudinal turnover likely due to topography-driven isolation. The improved knowledge of the ecological requirements of Syzygium assists in the elaboration of effective conservation strategies and improves in situ species identification of this taxonomically difficult group.

Solanaceous Vegetables and Colorectal Cancer Risk: A Hospital-Based Matched Case-Control Study in Northeast China.

Background: Dietary factors are regarded as an essential influence in changing colorectal cancer (CRC) risk. However, there is no clear conclusion of the relationship between solanaceous vegetables and colorectal cancer at present. The study aimed to evaluate the intake of solanaceous vegetables in relation to colorectal cancer risk among the Northeast Chinese population.Methods: We carried out a hospital-based case-control study in three hospitals in Northeast China from 2009 to 2011. The study finally included 833 patients with CRC and 833 controls matched separately according to age, gender, and city of residence. We applied a structural questionnaire to collect demographic characteristics and dietary information by face-to-face interview and adopted conditional logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Stratified analyses were conducted by sex and subsites.Results: There was no obvious correlation between total intake of solanaceous plants and CRC risk. The adjusted OR for the highest quartile and the lowest quartile was 1 (95% CI: 0.68–1.5). Certain types of solanaceous vegetables were negatively associated with the risk of CRC, such as eggplant (OR = 0.42; 95% CI:0.29–0.62) and sweet pepper (OR = 0.48; 95%CI: 0.33–0.7). Potato was found to have a positive correlation with CRC (OR = 1.76; 95% CI: 1.26–2.47). In the stratified analyses by gender, total solanaceous vegetables intake was inversely associated with CRC risk only in men. In the stratified analyses of cancer subsites, no significant association between total solanaceous vegetables intake and CRC risk was found.Conclusion: No findings showed that the intake of total solanaceous vegetables was related to the reduction of CRC risk. However, specific types of solanaceous vegetables indicated an inverse association with CRC risk.

Nature Exposure and Its Effects on Immune System Functioning: A Systematic Review

Given the drastic changes in our lifestyles and ecosystems worldwide, the potential health effects of natural environments have grown into a highly pervasive topic. Recent scientific findings suggest beneficial effects from nature exposure on human immune responses. This review aims at providing a comprehensive overview of literature published on immunomodulatory effects of nature exposure by inhalation of natural substances. A systematic database search was performed in SCOPUS and PubMed. The quality and potential bias of included studies (n = 33) were assessed by applying the EPHPP (Effective Public Health Practice Project) tool for human studies and the ARRIVE (Animal Research: Reporting of In Vivo Experiments) and SYRCLE (Systematic Review Centre for Laboratory Animal Experimentation) tools for animal studies. The synthesis of reviewed studies points to positive effects of nature exposure on immunological health parameters; such as anti-inflammatory, anti-allergic, anti-asthmatic effects or increased NK (natural killer) cell activity. Decreased expression of pro-inflammatory molecules, infiltration of leukocytes and release of cytotoxic mediators are outcomes that may serve as a baseline for further studies. However, partially weak study designs evoked uncertainties about outcome reproducibility and key questions remain open concerning effect sizes, duration of exposure and contributions of specific vegetation or ecosystem types.

Brazilian Forest Dataset: A new dataset to model local biodiversity

ABSTRACT The Intergovernmental Panel on Climate Change and the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services have emphasised unequivocal evidences about the impact of human actions on climate and biodiversity at alarming rates. In Brazilian terms, 2019 has been marked by controversial discussions among politicians and environmentalists, leading to misinformation and misinterpretations that clearly motivate the continuous collection and scientific analysis of data to support sustainable solutions. Aiming at dealing with this issue, this manuscript brings two contributions: (i) the creation of the Brazilian Forest Dataset, including Brazilian seed plants, Fraction of Absorbed Photosynthetically Active Radiation, meteorological and geographical data composing 8,482 attributes to model and predict 20 vegetation types; and (ii) the feasibility analysis on modelling this dataset in light of supervised machine learning algorithms, so we devise confident results on the Brazilian biodiversity. Experimental results confirm Random Forest and Support Vector Machines successfully adjust models, enabling researchers to predict the occurrence of specific types of vegetation in different regions of Brazil as well as analyse how the prediction accuracy changes along time after the collection of new data. Our contributions bring important tools to support the study on the evolution of the Brazilian biodiversity.

Dietary patterns and oesophageal cancer: a multi-country latent class analysis

BackgroundThe considerable differences in food consumption across countries pose major challenges to the research on diet and cancer, due to the difficulty to generalise and reproduce the dietary patterns identified...

Cascading response of flora and terrestrial mollusks to last deglacial warming

The cascading impacts of climate-driven vegetation change on terrestrial invertebrates via trophic and habitat routes is a matter of outstanding concern. However, the combined responses of plant-animal associations in terrestrial ecosystems have seldom been reported on geological timescales, which raises the important questions of how frequently and to what extent such multi-trophic shifts in taxa have occurred during previous warming scenarios. Here we use a combination of mollusk, palynological, and climatic proxy evidence preserved within loess deposits in the southern Chinese Loess Plateau (CLP) to demonstrate how long-term changes in hydroclimatic dynamics during the past 26 kyr were reflected in the subsequent ecological changes. Specifically, there was a shift from a predominantly cold-tolerant mollusk fauna in a dry-steppe environment under cold-dry conditions during the last glacial, to a predominantly thermal-mesophilous fauna in a meadow-steppe environment under a warm temperate climate in the early-middle Holocene. Warmth-adapted mollusk species such as Opeas striatissimum and Punctum orphana were found to have been associated with several deciduous tree taxa (e.g., Corylus, Quercus, and Pterocarya) in both the Holocene record and in the modern ecosystem (based on surveys of 356 surface-soil plots). This suggests there is a clear ecological interdependency between specific vegetation types and mollusk assemblages. As such, the long-term vegetation-mollusk fossil records highlight the indirect impacts of climate change on terrestrial invertebrate turnover via plant-derived food structure and habitat routes, with major implications for understanding how these ecosystems are likely to respond to future climate changes.

Everyone makes mistakes: Sampling errors in vegetation analysis - The effect of different sampling methods, abundance estimates, experimental manipulations, and data transformation

Understanding of causes for recent changes in vegetation structure and species richness of natural habitats is crucial for their maintaining for future generations. However, to avoid misinterpretation of vegetation changes in time, we should be aware of limits and errors of methods used for vegetation sampling. In a specific vegetation type, i.e. species rich wet meadow, we quantified sampling error in vegetation sampling at four different sampling levels (visual cover estimation, detailed recording in a grid of small cells, detailed assessment during clipping for biomass, biomass sorting), compared differences among three abundance estimates (frequency, cover and biomass), and assessed the effect of data transformation, and rapid change in vegetation structure caused by experimental species removal. At the 1 m2 scale the captured proportion of species missed by classical relevé sampling was on average 16%. Subsequent detailed subquadrat sampling captured the majority of previously overlooked species. The chance of a species being overlooked increased both with rarity, and the species richness of the area sampled. Where abundance was measured using metrics of cover and biomass, common species were overvalued, but when abundance was measured using frequency, common species were undervalued. In this study, logarithmic transformation of values provided a more reliable characterization of vegetation, than binarized or untransformed values. With the exception of species abundance, the number of species overlooked, quadrat species richness, and vegetation characterization were all affected by the experimental treatment. Our findings highlight the potential effects of error when conducting vegetation sampling and analyses of community dynamics. Due to these effects, we need to consider the reliability of conclusions drawn when assessing temporal changes in plant dynamics. Data transformation modifies the effect of sampling error in analyses of vegetation data.

Vegetation vs. Anoxic Controls on Degradation of Plant Litter in a Restored Wetland

The ability of wetlands to accrete organic matter in response to rising sea-level is a key to landscape resilience, especially in light of reduced sediment availability consequent to dam construction and channelization. This study examined degradation of cattail (Typha spp) and tule (Schoenoplectus acutus) litters in restored wetlands through the lens of lignin, a major structural biopolymer in vascular plants with degradation characteristics very sensitive to oxic vs. anoxic conditions. A series of litterbags were deployed during the first 10 years after flooding of Deep (55 cm) and Shallow (25 cm) restored wetlands. As emergent marsh vegetation spread through the maturing wetlands, anoxic conditions were more prevalent and overall degradation rates of litter in litterbags were lower. In later experiments in the maturing wetlands, lignin was progressively enriched in litter as evidenced by carbon-normalized yields (8) that increased in tule starting materials from 6.3 to 7.1 mg 100mgOC-1 to as high as 9.9 mg 100mgOC-1, and in cattail starting materials from 5.9 to 7.0 mg 100mgOC-1 to as high as 10.9 mg 100mgOC-1. However, in an experiment initiated soon after the restored wetlands were constructed, 8 in tule litter decreased from 6.8 to 3.6 mg 100mgOC-1, highlighting the prevalence of initial oxic conditions. With the exception of the early oxic conditions for tule there was an overall trend of decreasing lignin acid-to-aldehyde ratios with litter degradation, which runs counter to most studies in the literature. We hypothesize that this reflects the utilization of more oxygen-rich lignin components as electron acceptors in redox reactions. No consistent differences were observed in degradation patterns between the Shallow and Deep wetlands. There were distinct differences in lignin degradation in cattail (more resistant) vs. tule (less resistant), which indicates that although anoxia may be the dominant control on organic matter accretion in wetlands, specific types of vegetation in restored or constructed wetlands affects organic matter preservation, and hence accretion. Thus, selective management of predominant species in wetlands may prove important for the ability of wetlands to maintain emergent vegetation during sea-level rise and to preserve the overall stability of wetland soils.

Grazing and fouling behaviour of cattle on different vegetation types within heterogeneous semi-natural and naturalised pastures

In a two-year study, grazing, resting and fouling behaviour of cattle grazing on heterogeneous semi-natural/naturalised continuously grazed, fenced pasture areas (sites), were examined using two and nine sites in year 1 and 2. Five vegetation types were identified and mapped out on the sites used in the study: four typical species-rich semi-natural vegetation types (dry, mesic, wet, shaded), and one naturalised, grass-dominated type on former fertilised arable land. The two sites used in year 1 and seven sites in year 2 contained all five vegetation types, while one or two vegetation types (dry and wet) were absent on the remaing two sites in year 2. Behaviour was recorded over 24 h on three occasions in year 1, and on one occasion in year 2. During observation hours, animal behaviour (grazing/resting/other) and vegetation type grazed were recorded at 5-minute intervals and time and location of defecation and urination were recorded continuously. Vegetation types were sampled for herbage analysis directly after behaviour observations by cutting the vegetation in three random plots per type. Relative preference for grazing, resting and fouling was calculated for each vegetation type by dividing proportion of behaviour observations spent on a specific vegetation type by proportion of total area occupied by this vegetation type. The results showed that during both years, animals showed the greatest relative preference for the naturalised vegetation type when grazing or fouling (urination and defecation). The naturalised vegetation type also had the greatest content of metabolisable energy (from 9.8 to 10.1 MJ/kg DM) and crude protein (from 131 to 157 g/kg DM) and the least content of neutral detergent fibre (from 453 to 456 g/kg DM).

Linking tundra vegetation, snow, soil temperature, and permafrost

Abstract. Connections between vegetation and soil thermal dynamics are critical for estimating the vulnerability of permafrost to thaw with continued climate warming and vegetation changes. The interplay of complex biophysical processes results in a highly heterogeneous soil temperature distribution on small spatial scales. Moreover, the link between topsoil temperature and active layer thickness remains poorly constrained. Sixty-eight temperature loggers were installed at 1–3 cm depth to record the distribution of topsoil temperatures at the Trail Valley Creek study site in the northwestern Canadian Arctic. The measurements were distributed across six different vegetation types characteristic for this landscape. Two years of topsoil temperature data were analysed statistically to identify temporal and spatial characteristics and their relationship to vegetation, snow cover, and active layer thickness. The mean annual topsoil temperature varied between −3.7 and 0.1 ∘C within 0.5 km2. The observed variation can, to a large degree, be explained by variation in snow cover. Differences in snow depth are strongly related with vegetation type and show complex associations with late-summer thaw depth. While cold winter soil temperature is associated with deep active layers in the following summer for lichen and dwarf shrub tundra, we observed the opposite beneath tall shrubs and tussocks. In contrast to winter observations, summer topsoil temperature is similar below all vegetation types with an average summer topsoil temperature difference of less than 1 ∘C. Moreover, there is no significant relationship between summer soil temperature or cumulative positive degree days and active layer thickness. Altogether, our results demonstrate the high spatial variability of topsoil temperature and active layer thickness even within specific vegetation types. Given that vegetation type defines the direction of the relationship between topsoil temperature and active layer thickness in winter and summer, estimates of permafrost vulnerability based on remote sensing or model results will need to incorporate complex local feedback mechanisms of vegetation change and permafrost thaw.

Data-informed sampling and mapping: an approach to ensure plot-based classifications locate, classify and map rare and restricted vegetation types

A new approach to vegetation sample selection, classification and mapping is described that accounts for rare and restricted vegetation communities. The new method (data-informed sampling and mapping: D-iSM) builds on traditional preferential sampling and was developed to guide conservation and land-use planning. It combines saturation coverage of vegetation point data with a preferential sampling design to produce locally accurate vegetation classifications and maps. Many existing techniques rely entirely or in part on random sampling, modelling against environmental variables, or on assumptions that photo-patterns detected through aerial photographic interpretation or physical landscape features can be attributed to a specific vegetation type. D-iSM uses ground data to inform both classification and mapping phases of a project. The approach is particularly suited to local- and regional-scale situations where disputes between conservation and development often lead to poor planning decisions, as well as in circumstances where highly restricted vegetation types occur within a wider mosaic of more common communities. Benefits of the D-iSM approach include more efficient and more representative floristic sampling, more realistic and repeatable classifications, increased user accuracy in vegetation mapping and increased ability to detect and map rare vegetation communities. Case studies are presented to illustrate the method in real-world classification and mapping projects.

Ecosystem physio-phenology revealed using circular statistics

Abstract. Quantifying how vegetation phenology responds to climate variability is a key prerequisite to predicting how ecosystem dynamics will shift with climate change. So far, many studies have focused on responses of classical phenological events (e.g., budburst or flowering) to climatic variability for individual species. Comparatively little is known on the dynamics of physio-phenological events such as the timing of maximum gross primary production (DOYGPPmax), i.e., quantities that are relevant for understanding terrestrial carbon cycle responses to climate variability and change. In this study, we aim to understand how DOYGPPmax depends on climate drivers across 52 eddy covariance (EC) sites in the FLUXNET network for different regions of the world. Most phenological studies rely on linear methods that cannot be generalized across both hemispheres and therefore do not allow for deriving general rules that can be applied for future predictions. One solution could be a new class of circular–linear (here called circular) regression approaches. Circular regression allows circular variables (in our case phenological events) to be related to linear predictor variables as climate conditions. As a proof of concept, we compare the performance of linear and circular regression to recover original coefficients of a predefined circular model for artificial data. We then quantify the sensitivity of DOYGPPmax across FLUXNET sites to air temperature, shortwave incoming radiation, precipitation, and vapor pressure deficit. Finally, we evaluate the predictive power of the circular regression model for different vegetation types. Our results show that the joint effects of radiation, temperature, and vapor pressure deficit are the most relevant controlling factor of DOYGPPmax across sites. Woody savannas are an exception, where the most important factor is precipitation. Although the sensitivity of the DOYGPPmax to climate drivers is site-specific, it is possible to generalize the circular regression models across specific vegetation types. From a methodological point of view, our results reveal that circular regression is a robust alternative to conventional phenological analytic frameworks. The analysis of phenological events at the global scale can benefit from the use of circular statistics. Such an approach yields substantially more robust results for analyzing phenological dynamics in regions characterized by two growing seasons per year or when the phenological event under scrutiny occurs between 2 years (i.e., DOYGPPmax in the Southern Hemisphere).

Out of scale out of place: Black rhino forage preference across the hierarchical organization of the savanna ecosystem

AbstractThe successful conservation plans of megaherbivores necessitate precisely characterizing their ecological needs in order to optimize reproduction rates and reintroduction plans. The black rhino (Diceros bicornis L.) is among the most endangered species of megaherbivores in Africa and its conservation relies on nature reserves that are bound and habitat‐restricted. Therefore, identifying the optimal amount of space this species needs and the factors driving its habitat use are crucial for establishing reserve priority plans. Knowing that forage selection is an important component linked to herbivore spatial distribution, we combined 5 years of sightings data with observations of rhinos' vegetation type and forage preferences to address their forage selection across multiple spatial scales. We found that black rhinos' spatial distribution was negatively associated with ecosystem productivity, but positively associated with specific vegetation types that contain highly preferred, chemically distinct, plant species. Black rhinos thus occupy their habitat across space and time through selective foraging on preferred plants.

Estimating Urban Vegetation Biomass from Sentinel-2A Image Data

Urban vegetation biomass is a key indicator of the carbon storage and sequestration capacity and ecological effect of an urban ecosystem. Rapid and effective monitoring and measurement of urban vegetation biomass provide not only an understanding of urban carbon circulation and energy flow but also a basis for assessing the ecological function of urban forest and ecology. In this study, field observations and Sentinel-2A image data were used to construct models for estimating urban vegetation biomass in the case study of the east Chinese city of Xuzhou. Results show that (1) Sentinel-2A data can be used for urban vegetation biomass estimation; (2) compared with the Boruta based multiple linear regression models, the stepwise regression models—also multiple linear regression models—achieve better estimations (RMSE = 7.99 t/hm2 for low vegetation, 45.66 t/hm2 for broadleaved forest, and 6.89 t/hm2 for coniferous forest); (3) the models for specific vegetation types are superior to the models for all-type vegetation; and (4) vegetation biomass is generally lowest in September and highest in January and December. Our study demonstrates the potential of the free Sentinel-2A images for urban ecosystem studies and provides useful insights on urban vegetation biomass estimation with such satellite remote sensing data.

Assessing the conservation status of tree species declining in productive landscapes: the case of Eucalyptus argophloia

Eucalyptus argophloia is a species with a small geographic range occurring in a productive landscape with a subhumid climate. The past distribution of the species was assessed from remnant vegetation and standing paddock trees. The species grows in three specific vegetation types within its geographic range, and based on densities in remnant vegetation and reduction of habitat, it is estimated that the population has been reduced by 94.2%. There is very little regeneration of the species including on ungrazed roadsides, and further decline of the species is expected. The species can be categorised under IUCN Red Listing criteria as Critically Endangered. The present study provides a method for using habitat association, population decline and stand structure for conservation assessment of threatened tree species in productive landscapes.

Brazilian Forest Dataset

Dataset created to monitor the Brazilian vegetation combining 4 different systems: (i) an inventory of Brazilian seed plants created to map the country biodiversity; (ii) the Fraction of Absorbed Photosynthetically Active Radiation; (iii) the NASA Power database to include meteorological data; and (iv) the DATASUS system which makes available geographical information from Brazil. The final dataset comprises a large number of attributes including meteorological and vegetational features, which correspond to a total of 8 and 8471 attributes, respectively. Moreover, the dataset contains 20 labels and 865 geographical positions (latitude and longitude) used during the vegetation monitoring. This project makes available raw and preprocessed data, and Machine Learning models (including source codes) adjusted to : i) predict the occurrence of specific type of vegetation in different region without requiring a constant monitoring task; ii) monitor whether or not the prediction accuracy is changing after collecting new data, which provides an important tool to detect how the environment is evolving over time; and iii) study this dataset as an extra data source to better understand and simulate meteorological influences on predicted vegetation types. More information about the original datasets: (i) http://www.scielo.br/scielo.php?script=sci_arttext&pid=S2175-78602015000401085 (ii) https://fapar.jrc.ec.europa.eu/Home.php (iii) https://power.larc.nasa.gov/ (iv) http://datasus.saude.gov.br/

Effects of Distinguishing Vegetation Types on the Estimates of Remotely Sensed Evapotranspiration in Arid Regions

Accurate estimates of evapotranspiration (ET) in arid ecosystems are important for sustainable water resource management due to competing water demands between human and ecological environments. Several empirical remotely sensed ET models have been constructed and their potential for regional scale ET estimation in arid ecosystems has been demonstrated. Generally, these models were built using combined measured ET and corresponding remotely sensed and meteorological data from diverse sites. However, there are usually different vegetation types or mixed vegetation types in these sites, and little information is available on the estimation uncertainty of these models induced by combining different vegetation types from diverse sites. In this study, we employed the most popular one of these models and recalibrated it using datasets from two typical vegetation types (shrub Tamarix ramosissima and arbor Populus euphratica) in arid ecosystems of northwestern China. The recalibration was performed in the following two ways: using combined datasets from the two vegetation types, and using a single dataset from specific vegetation type. By comparing the performance of the two methods in ET estimation for Tamarix ramosissima and Populus euphratica, we investigated and compared the accuracy of ET estimation at the site scale and the difference in annual ET estimation at the regional scale. The results showed that the estimation accuracy of daily, monthly, and yearly ET was improved by distinguishing the vegetation types. The method based on the combined vegetation types had a great influence on the estimation accuracy of annual ET, which overestimated annual ET about 9.19% for Tamarix ramosissima and underestimated annual ET about 11.50% for Populus euphratica. Furthermore, substantial difference in annual ET estimation at regional scale was found between the two methods. The higher the vegetation coverage, the greater the difference in annual ET. Our results provide valuable information on evaluating the estimation accuracy of regional scale ET using empirical remotely sensed ET models for arid ecosystems.

Effects of field margins and other uncultivated fields on Orthoptera assemblages in the mountainous paddy field area of northeast Japan

To understand how farmlands help maintain biodiversity, we investigated the relationship between habitat heterogeneity and Orthoptera community composition on multiple spatial scales. First, we determined the impact of 12 environmental variables on the Orthoptera community diversity by sampling 37 quadrats in uncultivated fields over a broad spatial scale. Canonical correspondence analysis (CCA) demonstrated that environmental parameters influenced species composition. The first two canonical axes were associated with forest cover, grass (including harvested dried grass in some cases), bare or paddy fields, and plants with tall stems. Secondly, we conducted a local-scale survey of Orthoptera assemblages in an operational farm unit consisting of paddy fields, fallow fields, marginal grass fields, and secondary forests. Eleven Orthoptera species (46%) were found exclusively on specific vegetation types. Thirdly, we carried out a habitat-scale survey to elucidate the correspondence between consecutive spatial changes in vegetation and Orthoptera community composition in a paddy field and surrounding marginal fields. Even within narrower ranges, the compositional habitat heterogeneity induced changes in the dominant Orthoptera species composition. These results indicate that a high degree of habitat segregation occurs among Orthoptera species in field margins and in uncultivated fields, and that farmland management significantly affects spatial distribution of Orthoptera.