Human-induced Vegetation Changes Research Articles

The Spatio-Temporal Variation of Vegetation and Its Driving Factors during the Recent 20 Years in Beijing

As the most important city in China, Beijing has experienced an economic soar, large-scale population growth and eco-environment changes in the last 20 years. Evaluating climate- and human-induced vegetation changes could reveal the relationship of vegetation-climate-human activities and provide important insights for the coordination of economic growth and environmental protection. Based on a long-term MODIS vegetation index dataset, meteorological data (temperature, precipitation) and impervious surface data, the Theil-Sen regression and the Mann-Kendall method are used to estimate vegetation change trends in this study and the residual analysis is utilized to distinguish the impacts of climate factors and human activities on vegetation restoration and degradation from 2000 to 2019 in Beijing. Our results show that the increasing vegetation areas account for 80.2% of Beijing. The restoration of vegetation is concentrated in the urban core area and mountainous area, while the degradation of vegetation is mainly concentrated in the suburbs. In recent years, the vegetation in most mountainous areas has changed from restoration to significant restoration, indicating that the growth of mountain vegetation has continued to restore. We also found that in the process of urban expansion, vegetation browning occurred in 53.1% of the urban built-up area, while vegetation greening occurred in the remaining area. We concluded that precipitation is the main climatic factor affecting the growth of vegetation in Beijing’s mountainous areas through correlation analysis. Human activities have significantly promoted the vegetation growth in the northern mountainous area thanks to the establishment of environmental protection areas. The negative correlation between vegetation and the impervious surface tends to gradually expand outwards, which is consistent with the trend of urban expansion. The positive correlation region remains stable, but the positive correlation is gradually enhanced. The response of vegetation to urbanization demonstrated a high degree of spatial heterogeneity. These findings indicated that human activities played an increasingly important role in influencing vegetation changes in Beijing.

Human-induced fires and land-use change in Lubusz Land (western Poland) derived from Lake Lubińskie sedimentary record

Sediments of Lake Lubińskie were investigated to track human-induced vegetation and fire activity changes in Lubusz Land (western Poland). Geochemical data, as well as pollen, macrocharcoal, and statistical analyses (CONISS, CharAnalysis, PCA, BINCOR) allowed us to recognize the major phases of the human impact. At the beginning of the investigation period, 3000 years ago, the area had already experienced disturbances from humans caused by the Lusatian and Przeworsk cultures, followed by western Slavs, and modern society. Land cover changes were mostly related to deforestation and gaining arable lands. The forest communities shrank substantially also due to timber demand from the growing society. However, the pollen record shows that within the last ~50 years the area experienced forest regeneration. Wildfires played an important role in shaping the landscape in the area of Lake Lubińskie. Overall, 23 fires were identified within the profile showing relatively high fire frequencies (up to 4.8 fires per 500 years) between 600 −38/+36 BCE and 1 ± 206 CE as well as between 1065 ± 98 CE and 1380 ± 92 CE. The highest fire frequency was observed between the 1000s and mid-1400s, showing decreased fire return interval (FRI) and increased charcoal flux as well as progressive deforestation. These changes were related to the establishment of villages (e.g., Lubin village) and the presence of the Joannites. Fire was most commonly used as a land management tool to gain patches of land for agrarian purposes. PCA and BINOCR analyses suggest that most of the fires were set by humans, but natural causes of ignition cannot be excluded. The land-use changes affected the vegetation in the region, causing increased erosion and shifts in the geochemistry of the lake reflected in better bottom waters ventilation and progressive eutrophication.

Palaeoenvironmental changes in eastern Crimea over the last 7600 years inferred from a multi-proxy study of a sediment archive from Lake Chokrak

The study presents a multi-proxy archive from hypersaline coastal Lake Chokrak in eastern Crimea, a steppe region which is particularly susceptible to moisture fluctuations. XRF, organic carbon and nitrogen, and palynological analyses are used to reconstruct the evolution of the lake and landscape development around it and to provide information about the driving forces behind those changes, such as climate and human impact. The findings show that the basin was an open marine bay between 7640 and 5500 cal. yr BP. After 5500 cal. yr BP, the low rates of sea-level rise led to gradual infilling of the basin. The prevalence of mesic herb-grass steppe around the site, as well as the expansion of broad-leaved trees in the Crimean mountains, indicate relatively warm and humid climate conditions during the Mid-Holocene. Elemental proxies and marine NPPs point to a transition to lagoonal conditions from 4270 cal. yr BP. The progressive shallowing of the basin was accompanied by the spread of more xeric Artemisia-grass steppe, which suggests a shift to arid conditions. The occurrence of cereal pollen from 3660 cal. yr BP may indicate the first signs of cultivation in the study area. The active build-up of a sand barrier from 3000 cal. yr BP led to a gradual separation of the basin from the sea. By 900 cal. yr BP, the fully-formed sand barrier resulted in a transformation of the lagoon into a hypersaline lake. The closing of the lagoon was accompanied by an expansion of halophytic communities around the site. Human-induced vegetation changes became more pronounced with the development of agrarian and pastoral activities around the site from ca. 750 cal. yr BP.

Archaeopedological reconstruction of Middle Bronze Age subsistence farming in SW-Germany from sedimentary archives in the Western Allgäu

In the northern Alpine foreland, there was a shift at the transition from the Early Bronze Age (EBA, 2200–1600 BCE) to the Middle Bronze Age (MBA, 1600–1250 BCE). This shift was associated with a widespread abandonment of the pile-dwelling settlements around the pre-Alpine lakes and an expansion and intensification of low- and mid-altitude inland settlements. A research gap exists regarding the nature of MBA subsistence in these inland areas, which are considered unfavourable for agriculture.We analysed multi-layered colluvial and alluvial deposits in the agriculturally unfavourable Western Allgäu region to gain insights into MBA subsistence farming. Phases of deposition were determined by optically stimulated luminescence (OSL) technique and AMS radiocarbon (14C) measurements of charcoal. They provide a chronostratigraphic framework that is correlated to the local archaeological record. Subsistence farming was reconstructed using land use proxies such as phytoliths, charcoal spectra, urease activity to microbial biomass carbon (Cmic) ratios, faecal biomarkers, polycyclic aromatic hydrocarbons (PAHs) and heavy metals.The OSL and 14C ages indicate phases of deposition and land use during the MBA. They correlate with two recently excavated MBA inland settlements in the Western Allgäu. Human-induced vegetation change promoted open woodland comprising of Juniperus and Quercus at the expense of Abies and Fagus. The accumulation of charcoal and PAHs in MBA related colluvial horizons is most likely associated with the use of fire to maintain an open landscape. Partially increased urease activity to Cmic ratios and the appearance of Juniperus indicate the importance of livestock farming within the MBA subsistence.Our results show that there was an extensive and diversified subsistence economy in the Western Allgäu during the MBA. They thus reflect an adaptation of MBA farmers to the harsher climatic conditions of the Western Allgäu, where crop yields were certainly less predictable than, for example, in regions near Lake Constance.

Quantifying the Effects of Climate Change and Revegetation on Erosion-Induced Lateral Soil Organic Carbon Loss on the Chinese Loess Plateau

Erosion-induced soil organic carbon (SOC) loss substantially affects the redistribution of global organic carbon. The Chinese Loess Plateau, the most severely eroded region on Earth, has experienced notable soil erosion mitigation over the last few decades, making it a hotspot for soil erosion studies. However, the overall rate of SOC loss and spatiotemporal evolution under changing environments remain unclear. In this study, we investigated SOC loss from 1982 to 2015 in the severely eroded Hetong region of the Chinese Loess Plateau by combining the Revised Universal Soil Loss Equation (RUSLE) model and the localized enrichment ratio function derived from field observations and attributed the changes in SOC loss to climate- and human-induced vegetation changes. The results showed that SOC loss in the Hetong region was 64.73 t·km−2·yr−1, 16.79 times higher than the global average. Over the past 34 years, SOC loss decreased by 23.84%, with a total reduction of more than 105.64 Tg C since the change-point year. Moreover, our study found that vegetation changes dominated the changes in SOC loss in the Hetong region, contributing 89.67% of the total reduction in SOC loss in the Hetong region. This study can inform carbon accounting and sustainable catchment management in regions that have experienced large-scale ecological restoration.

European pollen-based REVEALS land-cover reconstructions for the Holocene: methodology, mapping and potentials

Abstract. Quantitative reconstructions of past land cover are necessary to determine the processes involved in climate–human–land-cover interactions. We present the first temporally continuous and most spatially extensive pollen-based land-cover reconstruction for Europe over the Holocene (last 11 700 cal yr BP). We describe how vegetation cover has been quantified from pollen records at a 1∘ × 1∘ spatial scale using the “Regional Estimates of VEgetation Abundance from Large Sites” (REVEALS) model. REVEALS calculates estimates of past regional vegetation cover in proportions or percentages. REVEALS has been applied to 1128 pollen records across Europe and part of the eastern Mediterranean–Black Sea–Caspian corridor (30–75∘ N, 25∘ W–50∘ E) to reconstruct the percentage cover of 31 plant taxa assigned to 12 plant functional types (PFTs) and 3 land-cover types (LCTs). A new synthesis of relative pollen productivities (RPPs) for European plant taxa was performed for this reconstruction. It includes multiple RPP values (≥2 values) for 39 taxa and single values for 15 taxa (total of 54 taxa). To illustrate this, we present distribution maps for five taxa (Calluna vulgaris, Cerealia type (t)., Picea abies, deciduous Quercus t. and evergreen Quercus t.) and three land-cover types (open land, OL; evergreen trees, ETs; and summer-green trees, STs) for eight selected time windows. The reliability of the REVEALS reconstructions and issues related to the interpretation of the results in terms of landscape openness and human-induced vegetation change are discussed. This is followed by a review of the current use of this reconstruction and its future potential utility and development. REVEALS data quality are primarily determined by pollen count data (pollen count and sample, pollen identification, and chronology) and site type and number (lake or bog, large or small, one site vs. multiple sites) used for REVEALS analysis (for each grid cell). A large number of sites with high-quality pollen count data will produce more reliable land-cover estimates with lower standard errors compared to a low number of sites with lower-quality pollen count data. The REVEALS data presented here can be downloaded from https://doi.org/10.1594/PANGAEA.937075 (Fyfe et al., 2022).

Streamflow decline threatens water security in the upper Yangtze river

The annual streamflow in the upper Yangtze River (UYR) declined by 36.6 billion m3 from 1961 to 2015. However, the contributions to this streamflow decline from different tributaries and the underlying causes remain unclear. Here we quantify the streamflow decline in the UYR and the impacts of climate change and human activities using a distributed hydrological model and statistical methods. Results show that the streamflow decline increased from the upstream to downstream regions. Combining hydrological simulation and statistical analysis, the contributions of climate change, human water consumption, reservoir impoundment and human-induced vegetation change on streamflow decline are estimated to be 62.5%, 19.7%, 18.4% and 1.8%, respectively. Specifically, human water consumption growth is consistent with the spatial pattern of population growth and industrial development, and the reservoir impoundments are mainly located in the middle and lower parts of the mainstream. In the Jialingjiang, the tributary with the largest drainage area in the UYR, human activities account for 63.6% of the streamflow decline, with the largest decline induced by human water consumption growth. Under climate change and population growth, the population under water stress (water resources available less than 1000 m3/capita/yr) increases in the Mintuojiang and Jialingjiang, where the major cities are centralized and the population density is high. This study provides a new perspective for understanding the status of water resources in the UYR and offers insights into the sustainable utilization of water resources in the future.

Insights on the roles of climate and human activities to vegetation degradation and restoration in Beijing-Tianjin sandstorm source region

Evaluating climate and human-induced vegetation change could support managing the sustainability of ecological environment. Based on the Normalized Difference Vegetation Index (NDVI) dataset, meteorological data (temperature, precipitation), land use data and statistical data, this study used a trend quantitative analysis to distinguish the relative roles of climate change and human activities on vegetation degradation and restoration from 1982 to 2015 in Beijing-Tianjin sandstorm source region. Our results demonstrated that the increased vegetation reached 63.8% of the study area during 1982–2015. Using piecewise linear regression method, we identified two turning points within the period 1982–2015 were 1994 and 2004, respectively. By considering the turning points, we found the increasing, decreasing, and increasing trend during 1982–1994, 1995–2004 and 2005–2015, respectively. In 1982–2015, 68.1% of the vegetation change was dominated by the combined effects of climate and human activities, whereas 25.4% was caused by human activities. During 1982–1994, the increasing trend of vegetation was due to favorable climate factors (26.8%) and the combined effects of both (45.4%). In 1995–2004, the vegetation degradation was driven by unreasonable human activities (13%) and the combined effects of unfavorable climate factors and unreasonable human activities (33.1%). However, with the implementation of ecological engineering, the positive human activities (8%) and the combined effects of both (59.1%) were responsible for vegetation restoration during 2005–2015. We noticed that precipitation was the main climate factor limiting regional vegetation change, the sensitivity of vegetation to precipitation was increasing over the study period. Nevertheless, human activities played an increasingly important role in regional vegetation. In particularly, the ecological engineering and increasing precipitation were the main factors for regional vegetation restoration in the past 10 years.

Human disturbance caused stronger influences on global vegetation change than climate change.

Global vegetation distribution has been influenced by human disturbance and climate change. The past vegetation changes were studied in numerous studies while few studies had addressed the relative contributions of human disturbance and climate change on vegetation change. To separate the influences of human disturbance and climate change on the vegetation changes, we compared the existing vegetation which indicates the vegetation distribution under human influences with the potential vegetation which reflects the vegetation distribution without human influences. The results showed that climate-induced vegetation changes only occurred in a few grid cells from the period 1982–1996 to the period 1997–2013. Human-induced vegetation changes occurred worldwide, except in the polar and desert regions. About 3% of total vegetation distribution was transformed by human activities from the period 1982–1996 to the period 1997–2013. Human disturbances caused stronger damage to global vegetation change than climate change. Our results indicated that the regions where vegetation experienced both human disturbance and climate change are eco-fragile regions.

Changes in sediment load in a typical watershed in the tableland and gully region of the Loess Plateau, China

Changes in sediment load of the Yellow River, and the contributing factors, have been widely studied and many valuable results have been reported. However, these studies were mainly conducted in the hill and gully region of the Loess Plateau, while studies on other regions, such as the tableland and gully region, which is more important for food production, and social and economic development, have rarely been reported. In this study, a typical watershed in this region was selected to analyze the changes in the sediment load between 1981 and 2016, and the contributions of its influencing factors. The Mann-Kendall (MK) test was applied to annual runoff and sediment load, and the year 1994 was identified as the year of mutation; thus, a baseline period (1981–1994) and a response period (1995–2016) were distinguished. By combined use of the Revised Universal Soil Loss Equation (RUSLE) and the Sediment Delivery Distributed Model (SEDD), sediment yields for the two periods were estimated, and compared with the corresponding measured data. The contributions of influencing factors, including natural factors (changes in rainfall and rainfall erosivisty) and anthropogenic activities (human induced vegetation change, slope terraced farmlands, and check dams in the stream networks), were analyzed. The results demonstrate that: 1) Sediment load in Yanwachuan watershed decreased substantially between the two periods; 2) Sediment load change was mainly influenced by human induced vegetation cover changes across the watershed, and check dams in the stream networks, which accounted for approximately 80% and 20% of the sediment load reduction, respectively; 3) The sediment trapped by the check dams are likely to increase in the future, thus effective measures should be implemented to protect check dams, and to ensure the effects of check dams on sediment reduction can be maximized. The results of this study help to understand the changes in sediment load in the tableland and gully region, and can provide valuable guidance on best practices in terms of local soil conservation management.

Complex and Cascading Triggering of Submarine Landslides and Turbidity Currents at Volcanic Islands Revealed From Integration of High-Resolution Onshore and Offshore Surveys

Submerged flanks of volcanic islands are prone to hazards including submarine landslides that may trigger damaging tsunamis and sediment-laden seafloor flows (called ‘turbidity currents’). These hazards can break seafloor infrastructure which is critical for global communications and energy transmission. Small Island Developing States are particularly vulnerable to these hazards due to their remote and isolated nature, small size, high population densities and weak economies. Despite their vulnerability, few detailed offshore surveys exist for such islands, resulting in a geohazard ‘blindspot’, particularly in the South Pacific. Understanding how these hazards are triggered is important; however, pin-pointing specific triggers is challenging as most studies have been unable to link continuously between onshore and offshore environments, and focus primarily on large-scale eruptions with sudden production of massive volumes of sediment. Here we focus on an area with a high volcanic sediment supply, which is also similar to locations (volcanic or not) where human-induced vegetation change over-supplies sediments to coastal margins. We address these issues by integrating the first detailed (2 m x 2 m) bathymetry data acquired from Tanna Island, Vanuatu with a combination of terrestrial remote sensing data, onshore and offshore sediment sampling, and documented historical events. Mount Yasur on Tanna has experienced low-magnitude Strombolian activity for at least the last 600 years. We find clear evidence for submarine landslides and turbidity currents, yet none of the identified triggers are related to major volcanic eruptions, in contrast to conclusions from several previous studies. Instead we find that cascades of non-volcanic events (including outburst floods with discharges of >1000 m3/s, and tropical cyclones), that may be separated by decades, are more important for preconditioning and triggering of landslides and turbidity currents in oversupplied sedimentary regimes such as at Tanna. We conclude with a general model for how submarine landslides and turbidity currents are triggered at volcanic and other heavily eroding mountainous islands. Our model highlights the often-ignored importance of outburst floods, non-linear responses to land-use and climatic changes, and the complex interactions between a range of coastal and tectonic processes that may overshadow volcanic regimes.

Reconstruction of the mid-to Late- Holocene history of vegetation and land-use in Petrešiūnai, north-east Lithuania: Implications from palaeobotanical and archaeological data

This study presents the results of multi-proxy investigations of mid-to late-Holocene vegetation dynamics and land-use history associated with the Petrešiūnai archaeological site, north-east Lithuania. Identified vegetation changes are discussed in the context of both natural and anthropogenic factors determined within the site and its surroundings. The initial stages of colonisation and the subsequent land-use dynamics are discussed by applying the results of biostratigraphical and archaeological-historical data. To explore these issues, a lacustrine sediment core obtained from the stand-scale sedimentary basin was studied using a microbotanical (pollen and microcharcoal) survey and 14C and magnetic susceptibility (MS) measurements. Associations between proxies were statistically tested. In addition, archaeological excavations were conducted within the area of the Petrešiūnai hill fort. The results obtained show the presence of a heavily forested landscape with broad-leaved deciduous trees dominating the taxa existed in the area until approximately 4800-4700 cal BC. Low magnitude fire activity mainly caused by the natural factors was recorded. The expansion of spruce and the gradual decrease in thermophilous taxa suggests a local-scale climatic reversal started prior to the general decline of the HTM (Holocene Thermal Maximum). The decay of broad-leaved taxa followed by the pronounced culmination of Picea-dominated forest (2100-1500 cal BC) confirms the general re-organisation of the forest structure in the area. A small-scale vegetation stress, accompanied by an increase in fire interference suggestive of episodic Neolithic-Bronze Age human activity, was noted in the area at approximately 2800-2200 cal BC, 1800 cal BC and 1500 cal BC. Biostratigraphical and sedimentological data suggest agriculture practices and animal husbandry were introduced and the landscape was increasingly utilised between 1300 and 1000 cal BC, which preceded the archaeological record of the Petrešiūnai hill fort by a few hundred years. However, as indicated by pollen data, pastoral farming predominated the local economy until approximately 400 AD. The establishment of regular cultivation practices, including crop rotation, and the formation of permanent fields with introduction of winter cereals began in the surroundings of Petrešiūnai by the 6th - 7th c. AD. At that time, the secondary open Betula-dominant vegetation successions flourished in the area. A highly diversified landscape with large agriculture fields, open grounds, meadows and pastures culminated in the area between 1000 and 1300 AD. After this period, the intensity of the human-induced vegetation changes apparently decreased, which confirms re-organisation of the settlement pattern and land-use in this area.

Palaeoecological evidence for climatic and human impacts on vegetation in the temperate deciduous forest zone of European Russia during the last 4200 years: A case study from the Kaluzhskiye Zaseki Nature Reserve

Climate change and human activity considerably influenced the temperate European deciduous forests through the Holocene, with the anthropogenic impacts being detected even in currently protected areas. This paper is focused on the area of the Kaluzhskiye Zaseki Nature Reserve, which contains remnants of primary broadleaved forests in central European Russia. Here, we present a new multi-proxy record including pollen, plant macrofossils, charcoal, loss on ignition and radiocarbon dating from the Mochulya peatland supplemented by 14 radiocarbon dates of charcoal fragments from soil pits in the study area. The results show that Mochulya peatland was a fen throughout the most of the time it existed. During the last 4200 cal yr BP the study area was occupied by broadleaved forests of Quercus, Ulmus, and Tilia. Picea became relatively abundant after 2300 cal yr BP. Despite the long-term human impact, vegetation fragments of these forests have persisted in the area until the present. Three main periods of deforestation and frequent fires were identified: 3700–3200 cal yr BP, 2000–1600 cal yr BP (the Early Iron Age) and 1000–400 cal yr BP (the Medieval Period). Whereas human-induced vegetation changes were apparent during the last two periods, vegetation dynamics during 3700–3200 cal yr BP were likely caused, at least in part, by climatic factors.

Modeling past human-induced vegetation change is a challenge – the case of Europe

Modeling past human-induced vegetation change is a challenge – the case of Europe

Profiling Human-Induced Vegetation Change in the Horqin Sandy Land of China Using Time Series Datasets

Discriminating the significant human-induced vegetation changes over the past 15 years could help local governments review the effects of eco-programs and develop sustainable land use policies in arid/semi-arid ecosystems. We used the residual trends method (RESTREND) to estimate the human-induced and climate-induced vegetation changes. Two typical regions in the Horqin Sandy Land of China were selected as study areas. We first detected vegetation dynamics between 2000–2014 using Sen’s slope estimation and the Mann–Kendall test detection method (SMK) based on the Moderate Resolution Imaging Spectroradiometer (MODIS) normalized difference vegetation index (NDVI) time series, then used RESTREND to profile human modifications in areas of significant vegetation change. RESTREND was optimized using statistical and trajectory analysis to automatically identify flexible spatially homogeneous neighborhoods, which were essential for determining the reference areas. The results indicated the following. (1) Obvious vegetation increases happened in both regions, but Naiman (64.1%) increased more than Ar Horqin (16.8%). (2) Climate and human drivers both contributed to significant changes. The two factors contributed equally to vegetation change in Ar Horqin, while human drivers contributed more in Naiman. (3) Human factors had a stronger influence on ecosystems, and were more responsible for vegetation decreases in both regions. Further evidences showed that the primary human drivers varied in regions. Grassland eco-management was the key driver in Ar Horqin, while farming was the key factor for vegetation change in Naiman.

Human-induced vegetation changes did not affect tree progeny performance in a seasonally dry forest of central Argentina

Regeneration by seed is scarce in seasonally dry mountain forests; in these areas, shrub-grass patches intermingled with remnant trees are widespread due to anthropogenic fires and post-fire livestock grazing. We hypothesized that progeny performance of remnant trees would be reduced due to soil loss, water limitation and damage to tree structures. We assessed the progeny performance of three tree species (70 trees per species) distributed in seven sites in central Argentina; in those sites, forest patches and shrub-grass patches with remnant trees coexist at a relatively close distance. Our main results showed no significant differences between progeny of trees located in forest patches and that of shrub-grass patches regarding seed mass, germination percentage in laboratory, seedling growth in greenhouse and survival and growth of outplanted saplings. Thus, our results do not support a hypothesis of human disturbances causing loss of progeny performance in remnant trees. Trees may be resistant to environmental changes, or there may be compensatory mechanisms, such as reduction of competition from neighbor trees, or increased resource allocation to reproduction at the expense of adult survival. We conclude that remnant trees are valuable resources for forest restoration because the quality of their progeny is still intact.

Optimization of the time series NDVI-rainfall relationship using linear mixed-effects modeling for the anti-desertification area in the Beijing and Tianjin sandstorm source region

Degradation in drylands is a critically important global issue that threatens ecosystem and environmental in many ways. Researchers have tried to use remote sensing data and meteorological data to perform residual trend analysis and identify human-induced vegetation changes. However, complex interactions between vegetation and climate, soil units and topography have not yet been considered. Data used in the study included annual accumulated Moderate Resolution Imaging Spectroradiometer (MODIS) 250 m normalized difference vegetation index (NDVI) from 2002 to 2013, accumulated rainfall from September to August, digital elevation model (DEM) and soil units. This paper presents linear mixed-effect (LME) modeling methods for the NDVI-rainfall relationship. We developed linear mixed-effects models that considered the random effects of sample points nested in soil units for nested two-level modeling and single-level modeling of soil units and sample points, respectively. Additionally, three functions, including the exponential function (exp), the power function (power), and the constant plus power function (CPP), were tested to remove heterogeneity, and an additional three correlation structures, including the first-order autoregressive structure [AR(1)], a combination of first-order autoregressive and moving average structures [ARMA(1,1)] and the compound symmetry structure (CS), were used to address the spatiotemporal correlations. It was concluded that the nested two-level model considering both heteroscedasticity with (CPP) and spatiotemporal correlation with [ARMA(1,1)] showed the best performance (AMR = 0.1881, RMSE = 0.2576, adj-R 2 = 0.9593). Variations between soil units and sample points that may have an effect on the NDVI-rainfall relationship should be included in model structures, and linear mixed-effects modeling achieves this in an effective and accurate way.

ДИНАМИКА РАСТИТЕЛЬНОСТИ НА ЮЖНОЙ ГРАНИЦЕ ЗОНЫ ШИРОКОЛИСТВЕННЫХ ЛЕСОВ ВОСТОЧНО-ЕВРОПЕЙСКОЙ РАВНИНЫ В СРЕДНЕМ И ПОЗДНЕМ ГОЛОЦЕНЕ

The paper presents new results of pollen and carpological analyses, as well as the plant macrofossil analysis and the radiocarbon dating of the peat profile of the Istochek peatland (the village of Yasnaya Polyana, Tula oblast). Based on these data, the reconstructions of vegetation dynamics on the north of the Middle Russian Upland during the Middle and Late Holocene were performed. The obtained data indicate that in the period 6500–4500 cal. years BP the study area was in the ecotone band between forest and steppe zones of the East European Plain. The boundary of the forest zone passed nearby the study area and was located in 50–70 km to the north in compare with its present position. Climate cooling and rise in moisture at 4500 cal. years BP led to increase of forested areas and shifted the forest boundary to the south. Human induced vegetation changes are traced in paleobotanical data from the Istochek peatland since 2000 cal. years BP, however dramatic environment deterioration when the natural vegetation was replaced by secondary forest stands and agricultural lands occurred during the last 300 years.

Quantifying the effectiveness of ecological restoration projects on long-term vegetation dynamics in the karst regions of Southwest China

To alleviate the severe rocky desertification and improve the ecological degradation conditions in Southwest China, the national and local Chinese governments have implemented a series of Ecological Restoration Projects (ERPs) since the late 1990s. This study proposed a remote sensing based approach to evaluate the long-term efforts of the ERPs started in 2000. The method applies a time-series trend analysis of satellite based vegetation data corrected for climatic influences to reveal human induced vegetation changes. The improved residual method is combined with statistics on the invested project funds to derive an index, Project Effectiveness Index (PEI), measuring the project effectiveness at county scale. High effectiveness is detected in the Guangxi Province, moderate effectiveness in the Guizhou Province, and low and no effectiveness in the Yunnan Province. Successful implementations are closely related to the combined influences from climatic conditions and human management. The landforms of Peak Forest Plain and Peak Cluster Depression regions in the Guangxi Province are characterized by temperate climate with sufficient rainfall generally leading to a high effectiveness. For the karst regions of the Yunnan and Guizhou Provinces with rough terrain and lower rainfall combined with poor management practices (unsuitable species selection, low compensation rate for peasants), only low or even no effect of project implementations can be observed. However, the effectiveness distribution is not homogeneous and counties with high project effectiveness in spite of complex natural conditions were identified, while counties with negative vegetation trends despite relatively favorable conditions and high investments were also distinguished. The proposed framework is expected to be of high relevance in general monitoring of the successfulness of ecological conservation projects in relation to invested funds.

Anthropogenic Transformation of the Vegetation in the Immediate Vicinity of the Settlement Complex at Poganowo (Mrągowo Lakeland, Ne Poland)

Abstract The results of pollen, non-pollen palynomorph and microcharcoal particle analyses of deposits from a small pond in north eastern Poland are presented. The study focused on human-induced vegetation changes that occurred in a close vicinity of the settlement complex at Poganowo during the Middle Ages (ca 10th-16th centuries). We distinguished three phases of human impact. First and third phases correspond to intensified settlement activity. The second phase was a period when human activity decreased and woodland regeneration took place. The high incidence of the parasitic fungus Kretzschmaria deusta in a local forest stand during the third phase was simultaneous with numerous spores of coprophilous fungi (Sordaria-type and Cercophora-type). We consider that Kretzschmaria deusta inhabited the roots and bases of tree trunks damaged by digging and grazing animals.