Major Land Use Research Articles

Biofuels and Land Use Change: Applying Recent Evidence to Model Estimates

Biofuels impact on global land use has been a controversial yet important topic. Up until recently, there has not been enough biofuels to have caused major land use change, so the evidence from actual global land use data has been scant. However, in the past decade, there have been 72 million hectares added to global crop cover. In this research we take advantage of this new data to calibrate the Global Trade Analysis Project (GTAP) model and parameters. We make two major changes. First, we calibrate the land transformation parameters (called constant elasticity of transformation, CET) to global regions so that the parameters better reflect the actual land cover change that has occurred. Second, we alter the land cover nesting structure. In the old GTAP model, cropland, pasture, and forest were all in the same nest suggesting, everything else being equal, that pasture or forest convert to cropland with equal ease and cost. However, we now take advantage of the fact that pasture converts to cropland at lower cost than forest. The paper provides the theoretical and empirical justification for these two model improvements. Then it re-evaluates the global land use impacts due to the USA ethanol program using the improved model tuned with actual observations. Finally, it shows that compared to the old model, the new model projects: (1) less expansion in global cropland due to ethanol expansion; (2) lower U.S. share in global cropland expansion; (3) and lower forest share in global cropland expansion.

Changes in soil microbial community structure and metabolic activity following conversion from native Pinus massoniana plantations to exotic Eucalyptus plantations

Afforestation after deforestation using fast growing exotic species is creating major land use changes throughout China and the world. However, few studies have looked at changes in soil microbial communities resulting from the planting of exotic species. With paired comparison design, we studied the effects of replacing a native Pinus massoniana plantation with an exotic Eucalyptus (Eucalyptus urophylla×grandis) plantation on the composition and carbon metabolic function of soil microbial communities in Guangxi Province, southern China. We compared the microbial biomass, phospholipid fatty acid (PLFA) composition and carbon metabolic function (BIOLOG profiles) between both plantation types. Results showed the abundance of bacterial, fungal, actinomycetal, and total phospholipid fatty acids, and the proportion of 16:1ω5c and five gram-negative characteristic bacterial PLFAs (of the six detected) in the Eucalyptus plantation soils were significantly lower than those of the P. massoniana plantations, as were biomass, carbon metabolic activity, and richness and diversity of the soil microbial community. The indicators denoting stress related to soil nutrient levels were significantly higher in the Eucalyptus plantation soils, such as the ratios of monounsaturated to saturated fatty acid, gram+ to gram− bacteria, iso- to anteiso-branched PLFA, and cy19:0 to 18:1ω7c. Canonical correspondence analysis (CCA) indicated the significant changes in the soil microbial community were mainly due to shrub and herb coverage, soil water content, soil organic carbon, soil N:P, and available N. Our research suggests forest conversion from native P. massoniana plantations to exotic Eucalyptus plantations alters the structure and function of the soil microbial community driven mainly by shifts in understory coverage and soil resource availability. Improved management practices, such as litter retention, reducing soil or understory disturbance during logging and subsequent establishment of the next rotation plantation, should be considered to help improve the metabolic function of soil microbial communities and increase soil resource availability during plantation management.

An Integrated Study on Sustainable Development of Groundwater Resources in Coastal Environs, Visakhapatnam District, Andhra Pradesh-A Watershed Approach

The study area, centered around the Madhurawada structural dome, lies in Visakhapatnam District of Andhra Pradesh State on the east coast of India. Covering 192 km 2 , the area consists of two non-perennial drainage basins of the Peddagedda River and Maddigedda rivulet. The average annual rainfall of the area ranges from 1000 to 1200 mm. There are about 50 surface water bodies of which eight are perennial. The population of the area in 2010 is estimated at 63,668. In this study, topographic maps, satellite images and geologic maps of the study area have been used to generate thematic maps of drainage, geomorphology, lineaments and land use/land cover. Cultivation is the major land use in the upper and lower reaches of the Peddagedda River whereas urban built-up occupies the watershed of Maddigedda rivulet. Twenty-four dug wells monitored during pre- and post-monsoon periods in 2010 revealed the area configuration of the water table. Analyses of these data in ArcGIS 9.2 environment helped to delineate zones with groundwater potential. Quality of groundwater revealing higher contents of hardness and fluoride in few villages have been affecting arthritis and mild gastrointestinal disorders as reported by Public Health Center. Following the guidelines of the Groundwater Estimation Committee-1997, studied available groundwater resources, current discharge and future requirements for the year 2025. The study area has been divided into run-off zones (about 57 km 2 ) and recharge zones (about 135 km 2 ) corresponding to hills and plains, respectively. The study area has total groundwater resources of 77,715,280 m 3 . The groundwater requirement in 2025 is estimated at 1,621 h.m/day. The study revealing surplus groundwater resources, population boom and recent developments have significant impact which leads to stress on groundwater. Keeping in view of this, drainage and geology were intersected and buffered to locate potential areas for artificial recharge of groundwater for sustainable occurrence to meet

Further insights into the role of land use in urban stormwater pollution

Purpose – The purpose of this paper is to analyse the urban stormwater quality with respect to different land uses, with a view to identifying areas of critical pollution. These areas can then be prioritised for applying best management practices.Design/methodology/approach – Major land use types of the study area were mapped. Sampling sites were selected on the basis of designated land use and land cover pattern. Grab samples of runoff were manually collected from the downstream direction of the road runoff in the designated sampling sites in the respective zones during the rainfall events and analysed.Findings – The stormwater quality varies with land use pattern. In industrial and commercial zones the pollutants were often found to exceed the permissible limits as per Indian standards. The spatial variation in pollutant distribution in the stormwater was highly influenced by the surrounding land use type.Practical implications – The relationship between stormwater quality and different land uses presen...

Land use practices and their implications on soil macro-fauna in Maasai Mara ecosystem

The composition, abundance, diversity and species richness of soil macro-fauna communities were assessed in four major land use types present within protected and agricultural landscapes in Maasai Mara savannah ecosystem (MME), Kenya. The four land uses were: natural grassland; woodland, inside and outside protected area; maize mono-cropping and maize-bean intercropping systems in adjacent agricultural farms. Sampling of soil macro-fauna was carried out in November, 2009 (short rain), April 2010 (wet rainy season) and September 2010 (dry season). Hand sorting of soil taken from 25 × 25 × 30 cm monoliths was used to extract all soil macro fauna greater than 2 mm body length. A total of 3,658 individuals comprising of 128 species mainly belonging to Phylum Arthropoda distributed across 3 classes and 13 orders, and Phylum Annelida with one order were collected across the four different land use systems. Termites and ants, and to a lesser extent coleopteran and earthworms were the most abundant groups. Significant effects of land use on macro-fauna abundance and species richness in all cases (p 50% and eliminating some Orders/Species. Human related disturbances outside protected area network declined macro-fauna density in grassland and woodland in dry region (65.07 vs. 39.74%) but increased the density by 107 vs. 340% in wet region. The study highlights the important effect of agriculture on macro-fauna communities and the need for conservation alternatives in unprotected areas. This study supports conservation of biodiversity beyond protected area network. Key words: Macro-fauna, grassland, woodland, agriculture, Maasai Mara, land use.

Land use influences on suspended sediment yields and event sediment dynamics within two headwater catchments, Waikato, New Zealand

Information on the effect of human-induced disturbances on sediment yields and sediment sources from New Zealand catchments is limited. This study analyses the sediment yields and event sediment dynamics for a 12-year period from two paired headwater catchments within the Waikato region. One catchment (Whakakai) was entirely vegetated in native forest, while the other (Mangaotama) was of mixed land use. Near the beginning of the study period, an integrated catchment management plan was implemented with the Mangaotama catchment. This plan included riparian planting, planting of degraded land in Pinus radiata and changes in stock management. Long-term in-stream turbidity data was calibrated with suspended sediment concentration (SSC) measurements and used to determine event and annual sediment yields. Hysteresis of the discharge (Q)–SSC relationship during events was used to infer differences in sediment sources. Event sediment yields within the Mangaotama catchment were similar to Whakakai catchment during small events (c. 1.01-year return period). For larger and less frequent events (>5-year return period), the event yields from Mangaotama exceeded Whakakai by about a factor of three, probably due to mass movement initiation. The specific sediment yield (±1σ) from Mangaotama (97±39 t/km2/year) was around 60% higher than Whakakai (60±22 t/km2/year). Clockwise hysteresis in the Q–SSC relationship dominated at Mangaotama, indicating the importance of near-channel sources. The persistence of near-channel source dominance throughout the study period (despite major land use changes) was attributed to switching of erosive mechanisms (i.e. from cattle-induced mechanical disturbance to subaerial processes). The prevalence of anti-clockwise hysteresis in the Q–SSC relationship of events at Whakakai suggests that hillslope sources are likely to be a principal source of eroded sediment. Such information provides valuable information that may help guide future decisions on the application of catchment rehabilitation measures.

Environmental factors associated with American cutaneous leishmaniasis in a new Andean focus in Colombia

To evaluate the environmental and ecological factors associated with Leishmania transmission and vector abundance in Chaparral, Tolima-Colombia. First, we compared the ecological characteristics, abundance of phlebotomies and potential reservoir hosts in the peridomestic environment (100 m radius) of randomly selected houses, between two townships with high and low cutaneous leishmaniasis incidence. Second, we examined peridomestic correlates of phlebotomine abundance in all 43 houses in the higher risk township. The high transmission township had higher coverage of forest (23%vs. 8.4%) and shade coffee (30.7%vs. 11%), and less coffee monoculture (16.8%vs. 26.2%) and pasture (6.3%vs. 12.3%), compared to the low transmission township. Lutzomyia were more abundant in the high transmission township 2.5 vs. 0.2/trap/night. Lutzomyia longiflocosa was the most common species in both townships: 1021/1450 (70%) and 39/80 (49%). Numbers of potential wild mammal reservoirs were small, although four species were found to be infected with Leishmania (Viannia) spp. In the high transmission township, the overall peridomiciliary capture rate of L. longiflocosa was 1.5/trap/night, and the abundance was higher in houses located nearer to forest (ρ = -0.30, P = 0.05). The findings are consistent with a domestic transmission cycle with the phlebotomies dependent on dense vegetation near the house.

Temporal and spatial variations in soil organic carbon sequestration following revegetation in the hilly Loess Plateau, China

Abstract Land use change is one of the major factors that affect soil organic carbon (SOC) variation and global carbon balance. Since the late 1970s, a significant area of the hilly Loess Plateau has undergone major land use changes during several revegetation programs, especially in the Grain for Green Project. However, so far there has not been a comprehensive study to determine temporal and spatial variations in SOC due to revegetation in this region, which hampers accurate predictions of the SOC sequestration potential and the land use change impacts. In this study, slope cropland and five typical revegetation types in the hilly Loess Plateau were selected, and then classified into 36 groups according to different revegetation years and landforms to investigate temporal and spatial variations of SOC and the impacts of relevant factors following revegetation. The results showed that the SOC concentration in the top soil horizon (0–5 cm) increased most significantly with revegetation and that increases in SOC slowed with increasing soil depth, but coefficient of variations in different soil horizons indicated that revegetation could cause SOC concentration differences at up to a 30 cm depth. Temporal variation in SOC occurred in two main phases in replanted cropland: in the first 10 or 15 yr, the profile mass of SOC (SOC density, SOCD) increased slightly; after this phase, SOCD increased significantly, with sequestration rates of 0.69, 0.55 and 0.24 t·ha − 1 ·yr − 1 (revegetation 10 to 35 yr) for planted woodland, planted shrubland and abandoned cropland, respectively. The SOC sequestration rate in wild grassland was 0.23 t·ha − 1 ·yr − 1 (revegetation 10 to 35 yr), which was similar to that in abandoned cropland. In contrast, the SOCD in wild shrubland increased rapidly in the first 10 yr, with a rate of 0.93 t·ha − 1 ·yr − 1 , and then by 0.56 t·ha − 1 ·yr − 1 over the next 25 years. SOCD spatial differences in different landforms had reached several times the annual SOCD increment and followed a new trend after revegetation: SOC sequestration in shady slope areas was significantly higher than in sunny slope areas, but no significant difference was found between gentle slopes and steep slopes after revegetation. A general linear model was used to identify the factors that were most relevant to SOC variation. Revegetation years accounted for nearly half of the total contribution to SOC variation (42%), and land use type was responsible for 33% of SOC variation. SOCD distribution in a watershed confirmed that variables of land use and years after revegetation dominated SOC variation. Landforms had a small influence on SOC variation at the regional scale, but the influence of the slope aspect was still large. The SOC sequestration rate was about 0.21 to 0.64 t·ha − 1 ·yr − 1 with revegetation in the hilly Loess Plateau, which was highest in wild shrubland, followed by planted woodland, planted shrubland, abandoned cropland and wild grassland. Considering the large area of revegetation and relatively high SOC sequestration rate, SOC sequestration in this region should contribute significantly to decreasing the carbon concentration in atmosphere.

36 year trends in dissolved organic carbon export from Finnish rivers to the Baltic Sea

Increasing dissolved organic carbon (DOC) concentrations in lakes, rivers and streams in northern mid latitudes have been widely reported during the last two decades, but relatively few studies have dealt with trends in DOC export. We studied the export of DOC from Finnish rivers to the Baltic Sea between 1975 and 2010, and estimated trends in DOC fluxes (both flow normalised and non-normalised). The study encompassed the whole Finnish Baltic Sea catchment area (301,000km2) covering major land use patterns in the boreal zone. Finnish rivers exported annually over 900,000t DOC to the Baltic Sea, and the mean area specific export was 3.5t km−2. The highest export (7.3t km−2) was measured in peat dominated catchments, whereas catchments rich in lakes had the lowest export (2.2t km−2). Inter-annual variation in DOC export was high and controlled mainly by hydrology. There was no overall trend in the annual water flow, although winter flow increased in northern Finland over 36years. Despite the numerous studies showing increases in DOC concentrations in streams and rivers in the northern hemisphere, we could not find any evidence of increases in DOC export to the northern Baltic Sea from Finnish catchments since 1975.

Gradual, catastrophic and human induced environmental changes from a coastal lake, southern New Zealand

Cores obtained from a coastal freshwater lake (Lake Waihola, South Island, New Zealand) show a >4000year history of environmental changes driven by significant variations in marine influence and anthropogenic modification of the catchment and minor contributions such as possible palaeotsunami inundation, all taking place against a background of sea level and landscape change. A marked shift from estuarine conditions (salinity >14ppt) to a predominantly freshwater state occurred around the mid-Holocene. This shift is recorded as a distinct change in diatom assemblages and by the disappearance of the estuarine bivalve Austrovenus stutchburyi from the sedimentary record. More recently, a marked change in sediment characteristics and changes in the pollen record correlate with rapid anthropogenic land clearance and conversion of the catchment to intensive agriculture in the mid 1800's. The mean rate of sediment accumulation between c. 4000yr BP and the start of major European settlement (c. AD1860) were around 0.18±0.01mmyr−1. From c. AD1860 onwards, this has increased markedly by about 30 fold following major land use changes in the catchment. Based on current predictions of sea level rise and sediment accumulation, various future sea level rise scenarios will more than compensate for infilling, resulting in the persistence of this aquatic system, which is expected to revert to an estuarine state.

Impacts of climate gradients on the vegetation phenology of major land use types in Central Asia (1981–2008)

Time-series of land surface phenology (LSP) data offer insights about vegetation growth patterns. They can be generated by exploiting the temporal and spectral reflectance properties of land surface components. Interannual and seasonal LSP data are important for understanding and predicting an ecosystem’s response to variations caused by natural and anthropogenic drivers. This research examines spatio-temporal change patterns and interactions between terrestrial phenology and 28 years of climate dynamics in Central Asia. Long-term (1981–2008) LSP records such as timing of the start, peak and length of the growing season and vegetation productivity were derived from remotely sensed vegetation greenness data. The patterns were analyzed to identify and characterize the impact of climate drivers at regional scales. We explored the relationships between phenological and precipitation and temperature variables for three generalized land use types that were exposed to decadelong regional drought events and intensified land and water resource use: rainfed agriculture, irrigated agriculture, and non-agriculture. To determine whether and how LSP dynamics are associated with climate patterns, a series of simple linear regression analyses between these two variables was executed. The three land use classes showed unique phenological responses to climate variation across Central Asia. Most of the phenological response variables were shown to be positively correlated to precipitation and negatively correlated to temperature. The most substantial climate variable affecting phenological responses of all three land use classes was a spring temperature regime. These results indicate that future higher temperatures would cause earlier and longer growing seasons.

Thematic maps for county-level land use planning in Contemporary China

Land use thematic maps are essential for the implementation of land use planning. China launched the third round of its land use planning in 2003, and the making of land use thematic maps series is one of the innovations for the new planning. The objective of this paper is to provide information about generating county-level land use thematic maps. The study area, Dachang Hui Autonomous County (178 km2), is located in Northern China and shares a boundary with Beijing. Methods for generating thematic land use maps are presented. These thematic maps include an existing land use map, zoning map for proposed land use, prime farmland protection map, zoning map for construction land expansion, planned land consolidation map, and planned major land use projects map. The scale for these maps is 1:50,000. All these maps are useful for researchers and local government, allowing them to be used as a reference for the study of land use mapping and support land resource management and planning.

Temperature‐related shifts in butterfly phenology depend on the habitat

AbstractMany species are becoming active earlier in the season as the climate becomes warmer. In parallel to phenological responses to climate change, many species have also been affected by habitat changes due to anthropogenic land use. As habitat type can directly affect microclimatic conditions, concurrent changes in climate and habitat could have interacting effects on the phenology of species. Temperature‐related shifts in phenology, however, have mostly been studied independent of habitat types. Here,Iused long‐term data from a highly standardized monitoring program with 519 transects to study how phenology of butterflies is affected by ambient temperature and habitat type.Icompared forests, agricultural areas and settlements, reflecting three major land use forms, and considered butterfly species that were observed in all three of these habitats. Seasonal appearance of the butterflies was affected both by the ambient temperature and the habitat type. As expected, warmer temperatures led to an overall advancement of the appearance and flight period of most species. Surprisingly, however, phenology of species was delayed in settlement habitats, even though this habitat type is generally associated with higher temperatures. A possible explanation is dispersal among habitat types, such that source–sink effects affect local phenology. When there is little productivity in settlement areas, observed butterflies may have immigrated from forest or agricultural habitats and thus appear later in settlements. My findings suggest that a spillover of individuals among habitats may affect phenology trends and indicate that phenological studies need to be interpreted in the context of habitat types. This becomes especially important when defining strategies to prevent or mitigate effects of climate and land‐use changes on phenology and abundance of species.

Remote sensing land-cover change in Port Elizabeth during South Africa’s democratic transition

Urban population increase has caused significant urban landscape transformation globally. Before 1994, South Africa’s highly regulated urban growth was shaped by the restrictive Prevention of Illegal Squatters Act of 1951. After the abolishment of the act in the 1980s, the period of transition to democracy in the 1990s was characterised by an unprecedented urban population influx that caused a myriad of socio-economic and environmental challenges. These challenges have consequently compounded the need to monitor urban growth for the planning and optimisation of urban spaces. The limitations of traditional mapping methods, such as surveying and photogrammetry, in urban mapping are well documented. In the recent past, satellite remote sensing has emerged as one of the most viable urban mapping tools. Using post-classification comparisons, we sought to monitor major land use and land cover (LULC) changes in the city of Port Elizabeth during South Africa’s democratic transition (1990–2000). Images for 1990, 1995 and 2000 were acquired, geo-rectified and atmospherically corrected. An iterative self-organising data analysis (ISODATA) was then used to generate existing LULCs. Classes generated using ISODATA were then amalgamated to the city’s major LULCs and resultant classes were validated using aerial photographs and field visits. Results showed that ‘Built-up’ and ‘Bare surface’ LULC classes had the highest increase and decrease, respectively. There was no change in the ‘Beach or dune’ LULC, whereas ‘Green vegetation’ and ‘Water’ classes had minimal changes. This study illustrates the efficacy of remote sensing in monitoring urban change and the potential of remote sensing to aid decision-making in rapidly changing urban landscapes.

Watershed scale application of WEPP and EROSION 3D models for assessment of potential sediment source areas and runoff flux in the Mara River Basin, Kenya

Mara River basin is an internationally acclaimed and ecologically significant basin in the Lake Victoria basin. The recent trend in major land use change in the upstream (forest-to-agriculture conversion) has been the major driver for the current hydrologic alterations. Recent hydrologic data and observations show a reduction in dry season flow, increase in peak flows during wet seasons and an increase in sediment load. This has led to the need for more observation and modeling to understand the impacts of the various land use changes on the sediment and runoff characteristics of the watershed . Two physically based models (Erosion 3D and Water Erosion Prediction Project (WEPP)) were applied to predict the watershed scale sediment and runoff response. Watershed scale modeling results show that sediment yield and runoff vary by slope, land use and soil type. The spatial sediment budget also shows the variability in the erosion and deposition of sediment in the basin. Average simulated erosion in cultivated land was about 120 t/ha/yr and the lowest simulated erosion rate was on bush lands and grasslands, which may indicate change in land use has significant impact on soil erosion in the Mara River basin. It was shown that both WEPP and EROSION 3D models are useful tools for watershed scale application and estimation of runoff and sediment yield. ► We estimated sediment yield and runoff at watershed scale using two soil erosion models. ► We evaluated the two models using field runoff and sediment data. ► We found that sediment and runoff varies by land use, topography and soil type. ► The two models were comparable but WEPP model was better for sediment estimation. ► Agricultural areas contribute about 50% of the sediment budget in the watershed.

The challenge posed by newly discovered cryptic species: disentangling the environmental niches of long‐eared bats

AbstractAimThe discovery of cryptic species poses new challenges for species conservation. Species distributions and conservation status have to be re‐evaluated, and the ecological requirements within the species complex have to be re‐assessed to recommend adequate conservation guidelines. The recent discovery in Central Europe of the cryptic bat species Plecotus macrobullaris (Kuzjakin 1965) calls for a new appraisal of all three Plecotus species in that area.LocationSwitzerland.MethodsUsing mostly DNA‐identified records, we investigated the environmental niches (ecological niche factor analysis) of the three long‐eared bat species at the landscape scale and modelled their potential distributions. Discriminant analysis was used for interspecific niche comparisons.ResultsThe occurrence of all three species was best explained by proximity to rural settlements and warm summer temperature. Plecotus auritus (Linnaeus, 1758) was positively associated with transition zones from forests to other habitats within heterogeneous landscapes; Plecotus austriacus (J. Fischer, 1829) was more frequently found in orchards and vineyards. Plecotus macrobullaris was linked mostly with deciduous forests. P. auritus had the broadest niche, with occurrence predicted in most forested regions throughout Switzerland. The slightly narrower niche of P. macrobullaris mainly encompassed areas in the Central and Southern Alps. P. austriacus showed a very narrow niche and was predicted mainly in the lowlands, with its habitat requirements overlapping those of P. macrobullaris. Although a range overlap was predicted between P. austriacus and P. macrobullaris, current observations suggest a mostly parapatric distribution in Switzerland.Main conclusionsThe projected distributions confirm previous knowledge for P. auritus, but shed new light on the other two species. In contrast to the newly discovered P. macrobullaris, which is actually widespread in the Southern Alps of Switzerland, P. austriacus is restricted to warmer cultivated lowlands and thus may have suffered from recent major land use changes. We suggest reclassifying P. austriacus to a higher conservation status.

Historical landscape photographs for calibration of Landsat land use/cover in the northern Ethiopian highlands

ABSTRACTThe combined effects of erosive rains, steep slopes and human land use have caused severe land degradation in the Ethiopian Highlands for several thousand years, but since the 1970s, however, land rehabilitation programmes have been established to try to reverse deterioration. In order to characterize and quantify the transformations in the north Ethiopian Highlands, a study was carried out over 8884 km2 of the Tigray Highlands of northern Ethiopia. Using Landsat Multispectral Scanner and later Thematic Mapper imagery (1972, 1984/1986 and 2000), historical terrestrial photographs (1974–1975) and fieldwork (2008), we prepared land use and cover maps. For assessing the use of the historical terrestrial photographs, Landsat images from 1972 were classified using two different methods, namely conventional change detection (image differencing) and ground truthing (using the historical photographs of 1974–1975). Results show that the use of terrestrial photographs is promising, as the classification accuracy based on this method (Kappa coefficient 0·54) is better than the classification accuracy of the method based on image differencing (Kappa coefficient 0·46). Major land use and cover changes indicate the following: (1) a gradual but significant decline in bare ground (32 per cent in 1972 to 8 per cent in 2000); (2) a significant increase of bushland (25 to 43 per cent) and total forest area (including eucalypt plantations, 2·6 to 6·3 per cent); and (3) creation of numerous lakes and ponds. The dominant change trajectory (27 per cent of the study area) indicates a gradual or recent vegetation increase. These changes can be linked to the population growth and the introduction of land rehabilitation initiatives, complemented by growing awareness of land holders. Copyright © 2012 John Wiley & Sons, Ltd.

Anticipating the unexpected - managing pasture pest outbreaks after large-scale land conversion

Pasture pests are often held in check by natural enemies but we have observed that severe pest attack over a wide area can occur after large scale land use change. Data were reviewed from current projects and databases for pest density and damage records covering the past 30 years. The focus was on areas where large scale land change has been implemented, including new irrigation schemes, pasture development from tussock or scrub, and land moulding for drainage via "flipping" or "hump and hollow". In these situations, pest outbreaks reached unprecedented levels, e.g. 2200 grass grub larvae/m2 in the Amuri irrigation scheme, 770 porina larvae/m2 on the East Otago Plateau and 3500 manuka beetle larvae/ m2 at Cape Foulwind on the West Coast. With major land use change, a new environment is created where pest species are provided abundant resources and the initial invaders multiply rapidly, free from the pressure of natural enemies. Monitoring systems, to provide early warning of pest attack, and remediation strategies can be used to overcome damage by these pests. Keywords: Land development, pest outbreaks, grass grub, manuka beetle, porina

Large-Scale Hydrologic Modeling of the Michigan and Wisconsin Agricultural Regions to Study Impacts of Land Use Changes

Hydrologic variables in the Great Lakes region have been altered relative to pre-settlement conditions in response to major land use changes during the past 150 years. One of the goals of the present work is to develop a baseline scenario relative to which the impacts of land use changes on hydrological and environmental processes can be evaluated. In addition, this study can help in quantifying the potential impacts of future projected changes in land use in order to mitigate the negative impacts of these changes, especially in regard to a shift toward urbanization and second-generation bioenergy crop production derived from lignocellulosic crops. The present study explores the relationship between land use changes and hydrologic indicators within the agricultural regions of Michigan and Wisconsin. Two sets of land use data, the circa 1800 county base and the 2001 National Land Cover Dataset, were used to set up the Soil and Water Assessment Tool (SWAT) model. First, sensitivity analyses were performed based on both pre-settlement and current land use scenarios. Results showed that parameter sensitivity analysis may not always explain how the variation in model output can be attributed to different sources of variation in the model input. Therefore, effort should be made to determine the true importance of sensitive parameters by considering their placement in model algorithms. The model was then calibrated against measured daily streamflow data obtained from eight U.S. Geological Survey gauging stations. The impacts of land use changes were studied at three scales: subwatershed, watershed, and basin. At the subwatershed scale, most of the hydrologic behavior can be described by percent change in land cover. However, the trend was more apparent for land use conversion from mixed forest to urban and agriculture lands than for other land use conversions. At the watershed scale, significant differences were observed based on the long-term average hydrologic variables under the current and pre-settlement scenarios. In addition, an increase in evapotranspiration (up to 16.5%) and surface runoff (up to 93.9%) contribution to streamflow, a decrease in recharge to aquifers (up to -51.5%) and baseflow (up to -50.1%), and mixed impacts on water yield (-21.5% to 24.6%) were detected. However, at the basin scale, more than 70% of the study area experienced decreased lateral subsurface flow and recharge to aquifers, while 65% of the area experienced increased overland flow and minor changes in evapotranspiration and water yield.

Changes in the Management of Scottish Machair Communities and Associated Habitats from the 1970s to the Present

Machair is a cultural landscape of high conservation value, but concern has been raised about the possible impacts of land use change on biodiversity. Using a combination of interviews with crofters, farmers and township clerks alongside data from the June Agricultural Census, this article identifies the major land use changes that have occurred between the 1970s and the present (2009/2010). In crofting areas, there has been a substantial fall in the amount of arable cropping and a concentration of this land use practice on North and South Uist. Associated with this change is a reduction in strip cultivation, increased use of inorganic fertilisers and increased plough depths. In parallel, there have been changes on the crofting inbye: reduced cropping, a switch from hay to silage and a shift in summer grazing from the hill ground to the inbye. Both farming and crofting areas have seen a fall in cattle numbers and sheep numbers peaked prior to 2000, but in general land use has been more stable in farmed areas of the machair. Changes have been partly technology-led, but much of the change can be attributed to a reduction by half in the number of active crofters over this period.