Vegetation Condition Assessment Research Articles

Urban forest cover and ecosystem service response to fire varies across California communities

Urban fires that result from wildfires are an emerging, extreme event affecting communities and urban forests globally. However, much of the fire effects on urban ecosystems literature is primarily focused on Wildland-Urban Interface (WUI) areas, correlates of building loss, risk mitigation, and wildland vegetation and fuels. Three recent urban fires in California USA provided an opportunity to explore these effects on urban forests: the 2017 Tubbs (Santa Rosa) and Thomas (Ventura) and the 2018 Camp fire that burned Paradise. Accordingly, we analyzed pre- and post-fire neighborhood level urban tree cover (nUTC) change over 5 years using Sentinel and LiDAR data (10m resolution). Then, we explored the effects of fire severity on changes in several regulating ecosystem services (e.g., carbon, air pollution, stormwater). Findings from the Rapid Assessment of Vegetation Condition after Wildfire severity processes and other geospatial datasets show that fire effects were patchy with fire severity within neighborhoods ranging from unburned to extreme. We found that ~5 years after the fires, and relative to adjacent non-fire affected neighborhoods, Ventura and Santa Rosa’s nUTC is recovering to pre-fire levels while Paradise’s nUTC is being consistently lost over time. Ventura and Santa Rosa had 20-25% of their fire affected area outside established WUI boundaries. However, local-scale urban tree cover and ecosystem service supply are lagged, and recovery time depends on the surrounding biome and socio-ecological context. In inland, higher elevation communities – like Paradise – the recovery of nUTC and the associated ecosystem services might materialize over a much longer timeframe. Our study provides a roadmap to assess the response of urban wildfire-affected tree cover and ecosystem services across space and time. It is also one of the first assessments of fire effects on urban ecosystems and communities outside of WUI boundaries that are now experiencing increased threat from wildfires globally.

Comparative Verification of Leaf Area Index Products for Different Grassland Types in Inner Mongolia, China

Leaf area index (LAI) is a key indicator of vegetation structure and function, and its products have a wide range of applications in vegetation condition assessment and usually act as important input parameters for ecosystem modeling. Grassland plays an important role in regional climate change and the global carbon cycle and numerous studies have focused on the product-based analysis of grassland vegetation changes. However, the performance of various LAI products and their discrepancies across different grassland types in drylands remain unclear. Therefore, it is critical to assess these products prior to application. We evaluated the accuracy of four commonly used LAI products (GEOV2, GLASS, GLOBMAP, and MODIS) using LAI reference maps based on both bridging and cross-validation approaches. Under different grassland types, the GLASS LAI performed better in meadow steppe (R2 = 0.26, RMSE = 0.41 m2/m2) and typical steppe (R2 = 0.32, RMSE = 0.38 m2/m2); the GEOV2 LAI performed better in desert steppe (R2 = 0.39, RMSE = 0.30 m2/m2). When we assessed their spatial and temporal discrepancies during the period from 2010 to 2019, the four LAI products overall showed a high spatial and temporal consistency across the region. Compared with GLASS LAI, the most consistent to least consistent correlations can be ordered by GEOV2 LAI (R2 = 0.94), MODIS LAI (R2 = 0.92), and GLOBMAP LAI (R2 = 0.87). The largest differences in LAI throughout the year occurred in July for all grassland types. Limited by the location and number of sample plots, we mainly focused on spatial and temporal variations. The spatial heterogeneity of land surface is pervasive, especially in vast grassland areas with rich grassland types, and the results of this study can provide a basis for the application of the product in different grassland types. Furthermore, it is essential to develop highly accurate and reliable satellite-based LAI products focused on grassland from the regional to the global scale according to these popular approaches, which is the next step in our work plan.

Rapid, Landscape-Scale Assessment of Cyclonic Impacts on Mangrove Forests Using MODIS Imagery

Cyclones are a key disturbance in mangrove ecosystems, but it is challenging to assess post-storm impacts over large areas, along with the recovery of these systems at broad temporal scales. Given the high frequency of these events in the Sundarbans region, prompt and consistent assessment of vegetation conditions is an important research need. Several studies have assessed the impact of an extreme cyclone event in 2007 (Sidr); however, there is little agreement between the extent and severity of the disturbance footprint of the cyclone, and very few studies attempted to assess vegetation recovery. We used a MODIS (Moderate Resolution Imaging Spectroradiometer) time series (2001–2010) to calculate monthly plant productivity anomalies in Google Earth Engine. We summarized dry season anomalies to assess post-storm vegetation change and evaluate the recovery time. Approximately 2100 km2, primarily on the east side, were impacted by Sidr. The number of damaged pixels was reduced by 55% the following dry season (2008) and 93% in the dry season of 2009, indicating a near-full recovery 26 months after the event. Our results provide an additional line of evidence to provide a rapid assessment of the post-storm vegetation damage. The simple framework used can provide a comprehensive view of the extent of the damage, including lag effects on vegetation, in just a matter of months after the event.

Heat and smoke from wildfires influence water temperature and dissolved oxygen levels in headwater streams

Wildfire has become increasingly common and severe in forested landscapes across the western United States. Stream and air temperatures within these landscapes are influenced not only by direct heating during the fire but by shading from heavy smoke. In addition, dissolved oxygen (DO) can be affected by increased ash inputs from fire or reduced primary production under lower light conditions. Because collecting data as the event occurs is challenging, most research exploring fire effects on streams has focused on responses months to years after the event as opposed to during and immediately after the fire. We sought to understand how physical stream parameters change as wildfire burns near streams, how stream temperature responses vary through a stream reach, how parameters respond to shading from pervasive smoke during and shortly after the fire, and how fire severity correlates with observed changes. In this study, we report measurements of light, air temperature, stream temperature, and DO across eleven 2nd- to 4th-order streams in the western Cascade Mountains of Oregon, USA, 1 wk before, during, and 1 wk after an extensive wildfire in 2020. Burning near streams resulted in a brief increase in daily maximum stream temperature of 4.5°C at the most severely burned site but small increases or decreases at less affected sites. Longitudinal replication revealed that temperature responses can be patchy at relatively small scales (∼50 m). DO daily minima decreased by 1.3 to 16.9% saturation on the day of the fire, with the magnitude of effect corresponding to burn severity. Across all 11 sites, riparian and watershed estimates of Rapid Assessment of Vegetation Condition after Wildfire and soil burn severity were better correlated with stream temperature responses to fire than percentage of watershed burned. Smoke effects were pervasive, both spatially and temporally, resulting in decreased light, stream temperature maxima, and diurnal variation in DO. Our results suggest that acute changes to physical stream parameters caused minimal harm to aquatic biota at our sites, and the effects of smoke on physical stream parameters will likely impose larger immediate effects on headwater streams than heating from the fire itself.

Trends in the Environmental Conditions, Climate Change and Human Health in the Southern Region of Ukraine

The Kherson, Mykolaiv, Odesa, and Zaporizhzhia oblasts, being adjusted to the coasts of the Black and Azov Seas, are located in the steppe zone and constitute the southern region of Ukraine. The environmental parameters and health indicators of the population of the region are sensitive to the impact of natural (e.g., climate change) and anthropogenic processes. An analysis of satellite remote sensing data (NOAA NDVI time series) for the assessment of vegetation condition demonstrates an increase in frequency and duration of drought events in the region during the last few decades. It may have a relation to climate change processes. Data analysis of local meteorological observations over the past 100 years proved alterations of some bioclimatic indexes. The Equivalent Effective Temperature (IEET) increases in winter and summer (due to the increasing repeatability of high anomalous temperatures) and remains stable in spring and autumn seasons. The increasing number and variability of climate anomalies can provoke an increase in cardiovascular and some other diseases in the local population. At the same time, an analysis of the statistical data of health indicators of the population (such as morbidity of digestion, breathing, and the endocrine and circulatory systems) shows a tendency to decrease morbidity (contrary to the indicators of the mountain regions’ population, which have higher values of life expectancy). Interrelations between environmental, climate change, and population health indicators in the Black Sea region are being discussed.

Monitoring long-term riparian vegetation trends to inform local habitat management in a mountainous environment

Riparian ecosystems provide critical habitat for many species, yet assessment of vegetation condition at local scales is difficult to measure when considering large areas over long time periods. We present a framework to map and monitor two deciduous cover types, upland and riparian, occupying a small fraction of an expansive, mountainous landscape in north-central Wyoming. Initially, we developed broad-scale predictions of predominant woody vegetation types by integrating Landsat data into species distribution models and combining subsequent outputs into a synthesis map. Then, we evaluated a 35-year Landsat time series (1985–2019) using the Mann-Kendall test to identify significant trends in the condition of upland and riparian deciduous vegetation and assessed the rate and direction of change using the Theil-Sen estimator. Finally, we used plot level data to assess the utility of the framework to detect bottom-up controls (ungulate browse pressure and management actions) on vegetation condition. The synthesis map had an overall correct classification rate of 87% and field data indicated deciduous vegetation within 45 m of coniferous forest faces increased pressure of conifer expansion. The trend assessment identified consistent patterns operating at the landscape scale across both upland and riparian deciduous vegetation; a predominant greening trend was observed for 12 years followed by a 9-year browning trend, before switching back to a greening trend for the last 13 years of the study. Our results indicate trends are driven by the climate of the measurement period at the landscape scale. Although we did not find conclusive evidence to establish a strong link between browse pressure and satellite data, we highlight examples where prevailing trends can be overridden by local disturbance or management intervention. This framework is transferable to other understudied riparian environments throughout western North America to provide insight on ecohydrological processes and assess global and local stressors across broad spatiotemporal scales.

Using UAV to Capture and Record Torrent Bed and Banks, Flood Debris, and Riparian Areas

Capturing and recording fluvio-geomorphological events is essential since these events can be very sudden and hazardous. Climate change is expected to increase flash floods intensity and frequency in the Mediterranean region, thus enhancing such events will also impact the adjacent riparian vegetation. The aim of this study was to capture and record the fluvial-geomorphological changes of the torrent bed and banks and flood debris events with the use of UAV images along a reach of Kallifytos torrent in northern Greece. In addition, a novel approach to detecting changes and assessing the conditions of the riparian vegetation was conducted by using UAV images that were validated with field data based on a visual protocol. Three flights were conducted using the DJI Spark UAV. Based on the images collected from these flights, orthomosaics were developed. The orthomosaics clearly identified changes in the torrent bed and detected debris flow events after major flood events. In addition, the results on the assessment of riparian vegetation conditions were satisfactory. Utilizing UAV images shows great potential to capture, record, and monitor fluvio-geomorphological events and riparian vegetation. Their utilization would help water managers to develop more sustainable management solutions based on actual field data.

Stability of grain production in crop rotations in the steppe conditions of the Lower Volga region

The analysis of the influence of crop rotation types on the productivity of grain crops is given. The expediency and efficiency of cultivation in crop rotations with a displaced passage of development phases is justified. A comprehensive assessment of hydrothermal vegetation conditions has shown that winter and late grain crops are more adapted to steppe conditions than early spring crops. In all years of observation, when converted to grain units, it was revealed that the highest yield of grain is observed in the 9-month grain – grass crop rotation. Close to the dipole grain – fallow crop rotation 4, which are present winter, spring, late spring and early culture. Significantly lower yield of grain units in 2 – full and 3 – full grain - pair crop rotations compared to the above considered ones. In the arid chernozem steppe of the Volga region, the productivity of arable land and the stability of grain production increases if winter, late spring and early crops with a fallow area of no more than 25.0 % are present in crop rotations, which allows, observing the principle of technological diversity, to improve the environmental role of field crops and reduce negative changes in agroecosystems under the influence of unilateral anthropogenic influence.

Exploring evapotranspiration dynamics over Sub-Sahara Africa (2000-2014).

Monitoring changes in evapotranspiration (ET) is useful in the management of water resources in irrigated agricultural landscapes and in the assessment of crop stress and vegetation conditions of drought-vulnerable regions. Information on the impacts of climate variability on ET dynamics is profitable in developing water management adaptation strategies. Such impacts, however, are generally unreported and not conclusively determined in some regions. In this study, changes in MODIS (Moderate Resolution Imaging Spectroradiometer)-derived ET (2000-2014) over large proportions of Sub-Sahara Africa (SSA) are explored. The multivariate analyses of ET over SSA showed that four leading modes of observed dynamics in ET, accounting for about 90% of the total variability, emanated mostly from some sections of the Sudano-Sahel and Congo basin. Based on Man-Kendall's statistics, significant positive trends (α = 0.05) in ET over the Central African Republic and most parts of the Sahel region were observed. Over much of the Congo basin nonetheless, ET showed significant (α = 0.05) distributions of widespread negative trends. These trends in ET were rather found to be consistent with observed changes in model soil moisture but not in all locations, perhaps due to inconsistent trends in maximum rainfall and land surface temperature. However, the results of spatio-temporal drought analysis confirm that the extensive ET losses in the Congo basin were somewhat induced by soil moisture deficits. Amidst other prominent drivers of ET, the dynamics of ET over the terrestrial ecosystems of SSA appear to be a more complex phenomenon that may transcend natural climate variations.

Machine learning prediction of coffee rust severity on leaves using spectroradiometer data

The interest in using remote sensing data in agriculture, including plant disease assessments, has increased considerably in the last years. The satellite-based Sentinel-2 MultiSpectral Imager (MSI) sensor has been launched recently for multispectral vegetation condition assessment for agricultural and ecosystem applications. The aim of this pilot study conducted in the greenhouse using a hand-held spectroradiometer was to assess the utility of the same wavebands as used in the Sentinel-2 MSI in assessing and modeling coffee leaf rust (CLR) based on the non-linear radial basis function-partial least squares regression (RBF-PLS) machine learning algorithm, compared with ordinary partial least squared regression (PLSR). The RBF-PLS derived models satisfactorily described CLR severity (R 2=0.92 and RMSE=6.1% with all bands and R 2=0.78 and RMSE=10.2% with selected bands) when compared with PLSR (R 2 = 0.27 and RMSE = 18.7% with all bands and R 2 = 0.17 and RMSE = 19.8% with selected bands). Specifically, four bands, B2 (490 nm), B4 (665 nm), B5 (705 nm) and B7 (783 nm) were identified as the most important spectral bands in assessing and modeling CLR severity. Better accuracy was obtained for most severe levels of CLR (R 2=0.71 using all variables) than for moderate levels (R 2=0.38 using all variables). Overall, the findings of this study showed that the use of RBF-PLS and the four Sentinel-2 MSI bands could enhance CLR severity estimation at the leaf level. Further work will be needed to extrapolate these findings to the crop level using the Sentinel-2 platform.

Effect of Desertification on Some Selected Soil Properties in a Semi Arid Part of Northwestern Nigeria

Gudu, being a fringe local government area of Sokoto State of Nigeria, is in the heart of desertification zone of Nigeria where agriculture as the sole means of livelihood for the ever increasing population is endangered. The extent of the effect of desertification on the soil quality is unknown, and for sustainable livelihood, timely information on vegetation and soil resources of the area is of essence. It was therefore hypothesized that desertification has effect on the Soil Organic Carbon (SOC) and particle size. Objectives include assessment of vegetation condition of the area, vegetation change detection and identification of hotspots and assessment of soil properties in the hotspots. Biennial time series (1998 and 2014) of 1-km 10-day SPOT Normalized Difference Vegetation Index (NDVI) was subjected to Time Series Analysis (TSA). Vegetation change detection was carried out to isolate hotspots (improved and degraded areas) from which soil samples were taken. ANOVA was used to test for difference in the measured soil properties at P < 0.05. Results show a general reduction vegetation cover, typical of a semi arid environment. SOC was generally low but higher in improved vegetation areas. While the degraded areas were purely sandy, improved vegetation was either Sand clay loam or Loamy sand, indicating a relationship between SOC and soil texture. It was concluded that desertification had effect on the selected soil properties in the study area. Embarkation on massive afforestation programme and protection of existing forest reserves coupled with environmental education for the farmers were recommended.

Environmental assessment of vegetation and hydrological conditions in Everglades freshwater marshes using multiple geochemical proxies

Paleoecological reconstructions of environmental changes provide important information for Everglades restoration targets. Traditionally this has been achieved using a combination of biological and physical indicators. However, as microfossils may be sporadically abundant in Everglades soils, organic geochemical methods can provide information at the molecular level. To reconstruct vegetation trends over the last century, soil cores from Shark to Taylor Sloughs, the primary flowpaths of the southern Everglades, were examined using several geochemical proxies. The n-alkane derived biomarker Paq effectively distinguished organic inputs from sawgrass and slough habitats. Other proxies examined include Kaurenes, cyclic diterpenoids unique to sawgrass roots; biomarkers of algae (highly branched isoprenoids (C20HBIs) and Botryococcenes); lignin phenols as vascular plant indicators; and macrofossils. At all sites, soil profiles from sawgrass marshes showed vegetation had shifted over the last 100 years, from sloughs to sawgrass-dominated marshes, reflecting decreased water levels (shorter hydroperiods) induced by water management. Paleo-assessments of modern sloughs, however, indicate these habitats remained deeper water habitats throughout the period of record, though shifts toward shorter hydroperiod vegetation were observed. In Taylor Slough, evidence of increasingly dry conditions in sloughs was confirmed by seed inputs from woody species. At 3 of the 5 sites, recent increases in C20HBIs and Botryococcene concentrations indicated greater periphyton abundance, coincidental with increased mineral concentrations observed in surface waters during the mid-20th Century. Bulk proxies such as organic content and carbon:nitrogen ratios also supported findings of changes in relative contributions of microbial and higher plants in this ecosystem.

Early twenty-first-century droughts during the warmest climate

The first 13 years of the twenty-first century have begun with a series of widespread, long and intensive droughts around the world. Extreme and severe-to-extreme intensity droughts covered 2%–6% and 7%–16% of the world land, respectively, affecting environment, economies and humans. These droughts reduced agricultural production, leading to food shortages, human health deterioration, poverty, regional disturbances, population migration and death. This feature article is a travelogue of the twenty-first-century global and regional droughts during the warmest years of the past 100 years. These droughts were identified and monitored with the National Oceanic and Atmospheric Administration operational space technology, called vegetation health (VH), which has the longest period of observation and provides good data quality. The VH method was used for assessment of vegetation condition or health, including drought early detection and monitoring. The VH method is based on operational satellites data estimating both land surface greenness (NDVI) and thermal conditions. The twenty-first-century droughts in the USA, Russia, Australia and Horn of Africa were intensive, long, covered large areas and caused huge losses in agricultural production, which affected food security and led to food riots in some countries. This research also investigates drought dynamics presenting no definite conclusion about drought intensification or/and expansion during the time of the warmest globe.

How accurate is the local ecological knowledge of protected area practitioners?

The scarcity of environmental data means that other sources of information are needed to complement empirical evidence for conservation decisions. By regularly interacting with their local environment, protected area practitioners may generate local ecological knowledge (LEK) that can be used to inform management decisions. However, the accuracy of LEK is generally poorly understood, and no studies have assessed the accuracy of practitioners' personal knowledge, leading to a vital gap in our ability to best use this information to guide management. We measured the accuracy of practitioners' knowledge of the vegetation condition within protected areas, relative to an empirical vegetation condition assessment tool. Despite the vast majority of practitioners having only personal experiences to inform their judgments, we found that almost 60% of practitioners made assessments of vegetation condition that matched the empirical condition estimates. When inaccurate, practitioners tended to be conservative in their estimates of condition. Although underestimating condition in this way may waste resources through unnecessary management actions, this is likely to be preferable to overestimating condition and thus failing to protect biodiversity by prematurely ceasing restoration programs. We found no relationship between the accuracy of practitioners' LEK and their level of experience as a practitioner, their level of education, or their gender. We believe that under many circumstances practitioners can be a valuable and cost-effective source of information about the condition of the protected areas they manage, but that more research is needed to understand the wide range of factors that may contribute to how land managers build LEK and how management agencies can assist practitioners to build a good understanding of the conditions in their reserves.

FutureGen 2.0 Monitoring Program: An Overview of the Monitoring Approach and Technologies Selected for Implementation

Abstract The FutureGen 2.0 Project will design and build a first-of-its-kind, near-zero emissions coal-fueled power plant with carbon capture and storage (CCS). To assess storage site performance and meet the regulatory requirements of the Class VI Underground Injection Control (UIC) Program for CO 2 Geologic Sequestration, the FutureGen 2.0 project will implement a suite of monitoring technologies designed to 1) evaluate CO 2 mass balance and 2) detect any unforeseen loss in CO 2 containment. The monitoring program will include direct monitoring of the injection stream and reservoir, and early-leak-detection monitoring directly above the primary confining zone. It will also implement an adaptive monitoring strategy whereby monitoring results are continually evaluated and the monitoring network is modified as required, including the option to drill additional wells in out-years. Wells will be monitored for changes in CO 2 concentration and formation pressure, and other geochemical/isotopic signatures that provide indication of CO 2 or brine leakage. Indirect geophysical monitoring technologies that were selected for implementation include passive seismic, integrated surface deformation, time-lapse gravity, and pulsed neutron capture logging. Near-surface monitoring approaches that have been initiated include surficial aquifer and surface- water monitoring, soil-gas monitoring, atmospheric monitoring, and hyperspectral data acquisition for assessment of vegetation conditions. Initially, only the collection of baseline data sets is planned; the need for additional near- surface monitoring will be continually evaluated throughout the design and operational phases of the project, and selected approaches may be reinstituted if conditions warrant. Given the current conceptual understanding of the subsurface environment, early and appreciable impacts to near-surface environments are not expected.

Assessment of vegetation and soil conditions in restored mangroves interrupted by severe tropical typhoon ‘Chan-hom’ in the Philippines

Using a space-for-time substitution approach, we investigated the effects of a typhoon on the vegetation and soil development trajectories of monospecific stands of Rhizophora mucronata mangroves of different ages (6-, 8- 10-, 11-, 12-, 17-, 18- and 50-year stands). The vegetation and soil parameters were compared to a reference system comprised of mature, natural mangrove stands. Pre-typhoon measures of vegetation and soil parameters were compared with 1-mo, 7-mo and 9-mo post-typhoon. Prior to the occurrence of the typhoon, there were clear patterns of vegetation and soil development with age of the stands. The development trajectory was however interrupted by the occurrence of the typhoon. Severe damage was more apparent in older mangrove stands (11- and 18- year stands) with very low to no damage in the younger stands. The typhoon-impacted sites experienced a number of changes, including: complete defoliation; reduced living tree densities of 61–69 %; decreased above-ground biomass of 70–79 %; increased soil nutrient levels of 40–60 %; more waterlogged soils by at least 113 % and increased soil temperature of 8–10 °C. Cumulative tree mortality, compounded by the lack of seedling recruits and unfavourable soil conditions may limit long-term recovery of the typhoon-impacted stands.

ESTUDO DA DINÂMICA DO ÍNDICE DE VEGETACÃO POR DIFERENÇA NORMALIZADA (NDVI) NO NUCLEO DE SÃO RAIMUNDO NONATO-PI.

O presente trabalho tem como recorte espacial o Nucleo de Sao Raimundo Nonato, localizado no Sudeste do estado do Piaui. Este Nucleo e composto pelos seguintes municipios: Sao Raimundo Nonato, Dirceu Arcoverde, Sao Lourenco, Coronel Jose Dias e Bonfim do Piaui. A area de estudo localiza-se em ambiente climatico do tipo semiarido, com significativas variacoes espaciais e temporais de precipitacao, fato que tende a se refletir na protecao oferecida pela cobertura vegetal, elemento de suma importância nos estudos ambientais, devido a seu papel de acelerador ou atenuador de processos de degradacao. O NDVI, um indicador largamente empregado na analise e avaliacao das condicoes da vegetacao, foi utilizado neste estudo, que objetiva analisar a dinâmica interanual e sazonal do mesmo, considerando os anos de 1987 e 2007. A metodologia baseou-se no uso de imagens orbitais do satelite Landsat 5 e 7 TM, com diferentes datas de passagem, aliada a inspecoes a campo. Os mapas foram elaborados no software Idrisi 3.2. Os resultados indicam ter havido mudancas significativas nas classes de NDVI baixo, muito baixo e solo exposto entre os anos de 1987 e 2007. Houve decrescimo nas classes baixa de 3,2% para 0,7%; a classe muito baixa aumentou de 71,8% para 86,7% ja na classe solo exposto verificou-se reducao de 25% para 13,3%. A analise sazonal permite inferir uma reducao expressiva de solo exposto durante a estacao chuvosa na regiao, em funcao do aumento das precipitacoes, e o consequente aparecimento de especies vegetais anuais. Esta classe em outubro (estiagem) ocorre em 25% da area de estudo, em maio (fim periodo chuvoso) passa a representar apenas 0,8%, como consequencia tem-se a diminuicao dos riscos de degradacao.

Improving the Farmland Biodiversity Value of Riparian Buffer Strips: Conflicts and Compromises

The intensity of management of lowland grassland fields in the United Kingdom, coupled with the fact that such grasslands dominate much of the lowland landscape, means that there are now few opportunities for many plants, invertebrates, birds, or mammals to survive. The Scottish Agricultural College (SAC) has investigated whether fencing off the margins of such fields next to watercourses to control diffuse pollution has any positive impacts on biodiversity, based on assessments of vegetation composition and condition and structure of assemblages of invertebrates of importance as foodstuffs to farmland birds. Fencing watercourses increased the abundance of key groups of invertebrates. However, the invertebrate species diversity was not increased unless the margins were ≥ 5.4 m in width. Margins established in the study area to prevent access by livestock to watercourses or to enhance biodiversity are generally ≤ 2.6 m wide and are therefore unlikely to provide conditions for additional invertebrate species to use. The dense, tall swards within such margins are also unlikely to provide foraging opportunities for farmland birds. Management (such as low-intensity grazing by livestock in the margins) is essential to provide the conditions required for these groups, but this could conflict with the diffuse pollution mitigation aims. A compromise is proposed whereby limited autumn/winter grazing by livestock could be used to open the vegetation structure in the margins. Grazing by livestock at that time may be acceptable since it is not occurring in the period of main diffuse pollution concern (i.e., the fecal contamination of watercourses and bathing waters in the spring and summer). It is also essential that a landscape-scale approach is taken, driven by knowledge of the full needs of the species concerned, when deciding where best to target agri-environmental actions aimed at farmland bird conservation.

A composite threat indicator approach to monitor vegetation condition in the Wet Tropics, Queensland, Australia

Many indicators and indices have been previously developed to report biodiversity condition at a regional scale. However, none have specifically focused on vegetation condition as a surrogate for biodiversity, and also incorporated threats at multiple scales. Using five indicators (forest cover fragmentation, urbanisation, weeds, feral animals and road density) identified from the scientific literature and selected in collaboration with natural resource management (NRM) stakeholders to reflect the state of vegetation condition in the World Heritage-listed Wet Tropics Bioregion of Queensland, Australia, we constructed a simple composite threat index which allowed the spatial display of information at the regional and subregional scale. Using this approach we identified that the overall vegetation condition of the Wet Tropics in the period 2003–2007 was ‘good’, but at a finer scale five of the bioregions nine subregions had ‘moderate’ condition, and only four had ‘good’ condition. The primary threat contributing to the ‘moderate’ condition was vegetation fragmentation due to clearing for agriculture, housing and related transport infrastructure. The composite threat index approach provided managers with a report card for the Wet Tropics landscape which allows rapid assessment of vegetation condition and contributory threats, and thus prioritization for the allocation of limited resources to threatening processes at the subregional scale.

Assessing the assessors: Quantifying observer variation in vegetation and habitat assessment

Vegetation assessment protocols used in research, monitoring and statutory planning often rely on the consistent application of methods by multiple assessors. Consequently, a study was undertaken to evaluate the application of a vegetation condition assessment protocol by a range of assessors. The aim of the study was to quantify variation among assessors in their measurement of field-based vegetation attributes using Queensland’s BioCondition protocol, and to determine the effect of variability on the final condition score. The study consisted of 77 assessors, ranging from nil to 25 years experience in vegetation assessment, who each undertook an assessment at one site following training. Six of the 20 attributes used to derive the final condition score were not assessed consistently, this being because of a small number of assessors who had misinterpreted the protocol and had inappropriately assessed some attributes. Despite inclusion of outliers, 82% of assessors were within 10 points of the median condition score for the site. Based on the results, the definition and measurement of problematic attributes have been either clarified or removed from the revised assessment procedure. The study demonstrated that with training prior to use, assessors were able to consistently assess condition at the study site.