Early Land Use Research Articles

Forest encroachment in Eastern European forest-steppes at a decadal time scale

Abstract In the Eurasian forest-steppe, with increasing aridity, the balance between naturally co-existing forest and grassland patches is expected to shift towards grassland dominance in the long run, although feedback mechanisms and changes in land-use may alter this process. In this study, we compared old and recent aerial photographs of Hungarian forest-steppes to find out whether and how the forest proportion and the number of forest patches change at the decadal time scale. The percentage area covered by forest significantly increased in all study sites. The observed forest encroachment may be a legacy from earlier land-use: due to ceased or reduced grazing pressure, forests are invading grasslands until the potential forest cover allowed by climate and soil is reached. The number of forest patches significantly increased at one site (Fülöpháza), while it decreased at two sites (Bugac and Orgovány) and showed no significant change at the fourth site (Tázlár). This indicates that forest encroachment can happen at least in two different ways: through the emergence of new forest patches in the grassland, and through the extension and coalescence of already existing forest patches. Though the present work revealed increasing tree cover at a decadal time scale, the dynamic process should be monitored in the future to see how the vegetation reacts to further aridification. This could help devise a conservation strategy, as the woody/non-woody balance has a profound influence on basic ecosystem properties.

Exploring Divergent Patterns and Dynamics of Urban and Active Rural Developments—A Case Study of Dezhou City

Clarifying urban-rural spatial explicit structure changes is of great significance for understanding the urban-rural relationship evolution. Previous studies have mostly focused on urban internal spatial structure evolutions and less on the regional scale when it comes to exploring urban and rural evolutions. Nighttime light can timely reflect the human activities in regions and provides great potential for investigating the evolutions of urban and rural spatial explicit structures. Here, taking Dezhou City, a rapidly urbanizing city in China, as a case study, we employed the local contour tree method and nighttime light data to map urban and active rural extents from 2012 to 2020 and further explored their respective development processes. This study showed that unlike in rural regions, the internally explicit structures of urban regions were more complex, and there were often multiple hotspots inside them. The area of the urban-rural region increased significantly by 39.3% from 2012 to 2020 (p < 0.05). Populations were greatly responsible for the spatial explicit structure changes of urban and active rural regions. The urban and rural region rankings of the identified counties were basically consistent with the urban and rural population rankings. Unlike the perspectives of earlier land use (i.e., built-up land or impervious surface), this study underlined urban and active rural regions in view of the scope of active human activities. These results can likely help policymakers understand current active human activity extents and provide a data-based reference for future public services and infrastructure planning.

Why Your Bar Has Crime but Not Mine: Resolving the Land Use and Crime – Risky Facility Conflict

Interpretations of two bodies of crime-place research conflict. Land use and crime studies claim particular facilities increase crime. Risky facilities studies show most places of a single type have little or no crime, but a few of that type have a great deal of crime. How can a facility be generally criminogenic and mostly safe? To resolve this conflict, we make use of the fact that a single owner can own multiple facilities and each owner may have consistent management practices in their facilities. We first replicate findings of earlier land use studies with crime and land parcel data from Cincinnati. Second, we cluster land parcels by property owners and re-estimate the land use and crime relationship. The links between land use and crime in the replication decline or disappear after clustering. Findings suggest owners’ place management influences crime at their places, thus resolving the conflict between the two bodies of research.

Sand grain mineralogy and morphology under forest and grassland/arable fields in Eastern Hungary

Related to ongoing (re)forestation in the Great Hungarian Plain the short-term influence of changing land cover was studied on the grains of skeletal sandy soils. In three sampling areas with forest and grassy/arable control plots, the 0.1–0.2 mm grain size fraction of samples taken every 20 cm from the 0–100 cm sandy soil layer (totalling 22,509 grains) were separated and described with optical mineralogical microscope. In order to distinguish sand grains of forest-covered and control areas (grassland/arable land), the results of mineralogical and morphological observations were compared. It was revealed that the amount of feldspar grains is 8–9 times less than the amount of the quartz ones. The increase in the quartz/feldspar (q/fp) ratio is tied to the “consumption” of feldspars: the intense consumption of potassium by trees. Under the forest-covered fields, the number of in-situ crushed grains increased. Grains with etch pits are frequent in samples from the grasslands (except in Hajdúsámson). In samples of forest-covered areas a greatly increased number of brown grains with limonite and/or humus films were observed. The gained results can be useful in proving earlier land use in forested fields.

Tracing groundwater with low-level detections of halogenated VOCs in a fractured carbonate-rock aquifer, Leetown Science Center, West Virginia, USA

Measurements of low-level concentrations of halogenated volatile organic compounds (VOCs) and estimates of groundwater age interpreted from 3H/3He and SF6 data have led to an improved understanding of groundwater flow, water sources, and transit times in a karstic, fractured, carbonate-rock aquifer at the Leetown Science Center (LSC), West Virginia. The sum of the concentrations of a set of 16 predominant halogenated VOCs (TDVOC) determined by gas chromatography with electron-capture detector (GC–ECD) exceeded that possible for air–water equilibrium in 34 of the 47 samples (median TDVOC of 24,800pgkg−1), indicating that nearly all the water sampled in the vicinity of the LSC has been affected by addition of halogenated VOCs from non-atmospheric source(s). Leakage from a landfill that was closed and sealed nearly 20a prior to sampling was recognized and traced to areas east of the LSC using low-level detection of tetrachloroethene (PCE), methyl chloride (MeCl), methyl chloroform (MC), dichlorodifluoromethane (CFC-12), and cis-1,2-dichloroethene (cis-1,2-DCE). Chloroform (CHLF) was the predominant VOC in water from domestic wells surrounding the LSC, and was elevated in groundwater in and near the Fish Health Laboratory at the LSC, where a leak of chlorinated water occurred prior to 2006. The low-level concentrations of halogenated VOCs did not exceed human or aquatic-life health criteria, and were useful in providing an awareness of the intrinsic susceptibility of the fractured karstic groundwater system at the LSC to non-atmospheric anthropogenic inputs. The 3H/3He groundwater ages of spring discharge from the carbonate rocks showed transient behavior, with ages averaging about 2a in 2004 following a wet climatic period (2003–2004), and ages in the range of 4–7a in periods of more average precipitation (2008–2009). The SF6 and CFC-12 data indicate older water (model ages of 10s of years or more) in the low-permeability shale of the Martinsburg Formation located to the west of the LSC. A two-a record of specific conductance, water temperature, and discharge recorded at 30-min intervals demonstrated an approximately 3-month lag in discharge at Gray Spring. The low groundwater ages of waters from the carbonate rocks support rapid advective transport of contaminants from the LSC vicinity, yet the nearly ubiquitous occurrence of low-level concentrations of halogenated VOCs at the LSC suggests the presence of long-term persistent sources, such as seepage from the closed and sealed landfill, infiltration of VOCs that may persist locally in the epikarst, exchange with low-permeability zones in fractured rock, and upward leakage of older water that may contain elevated concentrations of halogenated VOCs from earlier land use activities.

A comparison of influences of cattle, goat, sheep and reindeer on vegetation changes in mountain cultural landscapes in Norway

Earlier land use in European mountains included grazing by different kinds of livestock, while today it may be more homogenous, and the grazing may have either been intensified or been abandoned. Different domestic animal species graze in different areas of the landscape. Therefore, grazing stocks composed of different species have an unequal effect on the landscape. This study compares the influence of four domestic animal species (cattle, sheep, goats, reindeer) on landscape dynamics in Jotunheimen, a Norwegian mountain range. Interviews and maps showing grazing land of domestic animals were performed to collect information about land use in the summer farm surroundings. Grazing pressure maps (prior to 1960 and 1960–2002) using the land use information obtained, and vegetation maps (from the 1960s and 2002) using aerial photographs, were digitized. Vegetation was spatially linked with grazing pressure using GIS and multiple multinomial and linear regressions were used to investigate each species’ effect on vegetation type change and displacement of the forest line, respectively. The results show that cattle grazing influenced transitions from grasslands, cattle together with goats affected transitions from heaths, and cattle, goats, and reindeer influenced displacement of the birch forest line. High grazing pressure from these three domestic animals suppressed forest and scrub establishment in open habitats. Only goats, however, caused transitions from scrub and birch forest to open vegetation types.

Anthropogenic land cover changes in a GCM with surface albedo changes based on MODIS data

AbstractThis study uses a global climate model (GCM) to investigate the climate response at the surface and in the atmosphere caused by land use change. The climate simulations are performed with the National Center for Atmospheric Research Community Land Model 3.5 (CLM3.5) coupled to the Community Atmosphere Model 3 (CAM3) and a slab ocean model. We use the Moderate Resolution Imaging Spectroradiometer (MODIS) surface albedo product to represent surface albedo in the CLM3.5 for both present day and to reconstruct the surface albedo for natural pre‐agriculture conditions. We compare simulations including vegetation changes and surface albedo changes to simulations including only surface albedo changes. We find that the surface albedo change is most dominant in temperate regions while the change in evapotranspiration drives the climate response in the tropics. Our results show that land cover changes contribute to an annual global warming of 0.04 K, but there are large regional differences. In North America and Europe, the surface temperatures decrease by − 0.11 and − 0.09 K, respectively, while in India the surface temperatures increase by 0.09 K. When we fix the vegetation cover in the simulations and let the climate changes be driven only by the differences in surface albedo, the annual global mean surface warming is reduced, and all three regions are now associated with surface cooling.We also show that the surface albedo value for cropland is of major importance in climate simulations of land cover change. The surface albedo effect is the main driving mechanism when the change in surface albedo between agricultural and natural vegetation is substantial. Finally, we argue that differences in the surface albedo value of cropland implemented in earlier land use change studies explain the diversity in the sign and magnitude of the climate response. Copyright © 2009 Royal Meteorological Society

Effects of changes in land use and land cover on sediment discharge of runoff in a typical watershed in the hill and gully loess region of northwest China

Land use plays a much more important role than other factors, such as climate, soil properties, topographic features, vegetation coverage, human activities and others, in affecting soil erosion and sediment discharge. In order to understand the effects of changes in land use on sediment discharge and to provide a theoretical basis for land use planning, management and ecological restoration, we used the controlled Qiaozidong watershed and the uncontrolled Qiaozixi watershed in the third sub-region of the Loess Plateau as examples and analyzed the effects of land use and land cover on the discharge of sediments. The results show that the impact of land use and land cover on the annual amount of sediment discharge is significant. Compared with the uncontrolled watershed during similar periods, the amount of sediment discharged from the controlled watershed was reduced by 44%, 75% and 86%, respectively, in wet, normal and dry years. In the controlled watershed, compared with the period from 1986 to 1994, the amount of sediments discharged was less during the period from 1995 to 2004. The impact of land use and land cover on sediment discharge demonstrated characteristics of seasonal fluctuation. The effects of sediment reduction in the controlled watershed were greater than those in the uncontrolled watershed in May and September. In the controlled watershed, the reduction effect coincided with the distribution of rainfall. The amount of discharged flood sediments is closely correlated with rainfall, rainfall intensity in a 60 min period and the volume of flood. The rainstorm-runoff process and the rainstorm-sediment discharge process demonstrate that land cover has a strong regulatory and control function in the flood process and sediment discharge in rainstorms. For the controlled watershed, given the same precipitation frequency distribution, the average amount of sediment discharged during the land use period from 1995 to 2004 was less than that during the earlier land use period from 1986 to 1994 under every recurrent period.

Traces of past sami forest use: An ecological study of culturally modified trees and earlier land use within a boreal forest reserve

The Samis have been present in the Swedish boreal forest for a long time. Their land‐use practices were dominant over vast tracts until the late nineteenth century, but little is known about their impact on forest ecosystems. In this study former land use around an old Sami settlement situated in a forest reserve was analysed through historical sources and field investigations. The area around the Sami settlement (about 2.5 ha) comprised young forest (mean age approximately 140 yrs) with little dead wood present. The forest outside this area was much older and contained more dead wood. Scars dating from 1721 to 1962 were found on 118 culturally modified trees, derived from bark‐peeling practices and blazes for marking trails and borders. The patterns found constitute a characteristic Sami forest landscape, well distinguished from other types of forest use. The results may be used to identify such areas to preserve crucial structures for posterity.

Traces of Past Sami Forest Use: An Ecological Study of Culturally Modified Trees and Earlier Land Use Within a Boreal Forest Reserve

Traces of Past Sami Forest Use: An Ecological Study of Culturally Modified Trees and Earlier Land Use Within a Boreal Forest Reserve

The Postglacial record of environmental history from Lago di Pergusa, Sicily

Lacustrine sedimients from Lago di Pergusa in central Sicily provide a Postglacial record of environmental change in the Mediterranean. Magnetic susceptibility measurements, lithofacies characterization and pollen analysis were carried out anid integrated to obtain a better reconstruction of the past 11000 years. The chronoogy is provided by AMS radiocarbon dates on macrofossils or bulk sediment, and by a tephra correlative with a late-Holocene explosion from the Etna volcano. The transition period related to the present interglacial reafforestation, characterized by increasing humidity, started about 10700 years BP. The onset of the wettest conditions of the Postglacial occurred at about 9000 years BP and lasted until about 7200 years BP. Then a trend towards aridification began. leading to very dry conditions at about 3000 years BP. An unquestionable human impact on vegetation is found from 2800 years BP, although earlier land use cannot be excluded. As the climate had already induced change in the vegetation, the well-known human occupancy during the last three millennia did not produce strong effects on the environment.