Changes In Landscape Composition Research Articles

Nitrogen leaching and groundwater recharge of alternative lawn conversions in subtropical climates

AbstractClimate change, recurrent droughts, and increasing urban water demands have limited water availability in urban landscapes. Water quantity challenges have led to irrigation restrictions and turfgrass removal programs. An experiment was conducted at the University of Florida, West Florida Research and Education Center, Jay, FL, to evaluate the effect of turfgrass conversion to other landscape types on nutrient leaching and groundwater recharge. In April 2021, all surface vegetation was removed from existing turfgrass plots using a sod harvester. Thereafter, plots were planted or covered with three landscape types: a pollinator landscape with flowering forbs (Mimosa sp., Coreopsis sp., and Phyla sp.) + turfgrass (Eremochloa ophiuroides); a nitrogen (N)‐efficient lawn (Arachis glabrata + Paspalum notatum); and a low‐input landscape with unplanted woodchip mulch. Undisturbed turfgrass (E. ophiuroides) served as a control. For 2 years, leachate samples were collected weekly from previously installed 168‐L drainage lysimeters for NO3‐N and NH4‐N load determination. Temporal changes in landscape composition, groundwater recharge, water use, and soil bulk density were also quantified. While the mulch leached 44.7 kg ha−1 NO3‐N year−1, this landscape still offers positive attributes, including erosion protection and water conservation. Conversely, the pollinator landscape minimized nitrogen leaching (8.3 kg ha−1 NO3‐N year−1) due to their relatively greater water use rates (3.56 mm day−1). The turfgrass and nitrogen‐efficient lawn returned ∼35% of the water inputs as groundwater recharge while maintaining relatively low nitrogen leaching (3.6 and 2.7 kg ha−1 NO3‐N year−1, respectively), making these landscapes efficient for protecting both water quality and quantity.

Landscape evolution in China’s key ecological function zones during 1990–2015

Landscape evolution has profound effects on ecosystems. Recently, some studies suggest that China has implemented plans leading in the greening of the world by mainly describing the changes based on satellite data. However, few studies have analyzed the policy effect on ecosystem improvement from the perspective of landscape pattern evolution. Among the numerous ecological policy plans, China’s key ecological function zones plan is an important one. In this study, we focus on depicting the long-term and large-scale landscape evolution in China’s key ecological function zones, which are accounting for 40.2% of China’s land area, and include four-type ecoregions where ecosystems are fragile or important, to comprehensively explore the environmental influences of policy planning. For this purpose, we first described the landscape composition changes and conversion mechanisms in China’s key ecological function zones from 1990 to 2015. Then we captured the detailed pattern evolution characteristics by landscape indices. The results show that these ecoregions were mostly evolving in an unfavorable direction in these 25 years, i.e. destruction of habitats and increment of fragmentation. Although greening areas increased based on other recent researches, the landscape pattern became worse, indicating it is necessary for the detailed analysis of landscape ecology and more accurate ecological planning. We also found the deterioration of the ecological environment had been uncharacteristically stopped or even improved in wind prevention and sand fixation ecoregions and biodiversity maintenance ecoregions after the implementation of this plan. Furthermore, we assumed that the policy is more prominent in these prohibiting sabotages and protecting areas with fragile ecological bases, which may be caused by the differentiated transfer payments in different ecoregions. Finally, some planning suggestions, such as stricter land use control, the regional balance of ecological transfer payments and deepening of ecological migration policies, etc., were proposed for promoting better future environmental changes.

Distinguishing the relative contributions of landscape composition and configuration change on ecosystem health from a geospatial perspective

Understanding the impact mechanisms of landscape composition and configuration change on ecosystem health (EH) is critical to ecosystem conservation and human well-being. However, existing studies mainly focused on EH changes due to combined effects of landscape composition and configuration change, while the individual impacts and spatial heterogeneity of these factors on EH remain unclear. Thus, taking Chongqing as an example, this study distinguished the relative contributions of landscape configuration and composition on EH based on scenario analysis method, and further explored how these impacts change between and within different topographic, geological and urbanization zones. The results showed that EH displayed an improving trend during 2000–2020, with the increasing areas distributed in the mountainous of southeast and northeast in Chongqing, largely influenced by increased forest landscape cohesion and their synergistic effects with forest expansion, accounting for 91.05 % and 87.86 % of the study area respectively, while the decreasing areas were mostly located in urban cores, dominated by changes in landscape composition (e.g. farmland reclamation and urban sprawl), accounting for 50.95 % of area proportion. The scenario analysis of EH showed that the areas dominated by landscape configuration were 5.39 times greater than the landscape composition under the same climate scenario. In terms of zoning comparison, the influence of landscape composition change on EH displayed the greatest difference within urbanization zones, while topographic zones for landscape configuration change. This paper provides a novel perspective to explore the impact of landscape pattern on EH, which is important to regional ecosystem conservation and land use management.

Population and movement ecology of two life‐history contrasting dung beetle species in a tropical human‐modified landscape

Abstract The study of population movements and abundance are useful to evaluate the reduction of biodiversity due to changes in landscape composition and configuration. These parameters are modulated by the effects of landscape on individuals' behaviours and species' life histories (e.g., specialists and generalists in forest use). We used hierarchical models and tools derived from network theory to evaluate how landscape characteristics affect the abundance and movement patterns of the neotropical dung beetle species Deltochilum mexicanum and Dichotomius satanas with contrasting life histories in a human‐modified landscape of a Mexican cloud forest. Movement and abundance patterns observed for both species and sexes showed opposite responses to the percentage of forest cover and edge density. The specialist species showed a higher abundance, lower movement and spatial distribution limited to the forest, whereas the generalist species showed a lower abundance, higher movement and unrestricted distribution. For both species, males tended to travel longer distances than females, but we observed no difference in the movement metrics between sexes. Our findings highlight the effects of landscape covariables on population structure and dynamics, predict spatial dynamics of species habitat use and could be evidence of functional connectivity at the landscape scale.

Spatial non-stationarity of water conservation services and landscape patterns in Erhai Lake Basin, China

Understanding the relationship between water conservation service (WCS) and landscape patterns is important for ecosystem management and water resources regulation. However, existing studies on the relationship between water conservation services (WCS) and landscape pattern mainly focus on the impact of landscape composition on WCS, but ignore the spatial effects of landscape configuration. Taking the Erhai Lake Basin as an example, this study quantified the spatial and the temporal distribution of WCS and analyzed the changes in landscape composition and configuration from 1990 to 2020. Subsequently, the spatial non-stationarity between WCS and landscape pattern was discussed by using a geographically weighted regression model. The results showed that urban and forest landscapes increased by 3189.96% and 18.34%, while grassland, shrub, and cropland landscapes decreased by 21.30%, 20.65%, and 16.23%, respectively, from 1990 to 2020. The fragmentation degree of urban landscapes increased, while the fragmentation degree of other landscapes decreased. The fragmentation and the heterogeneity of the overall landscape decreased, while the aggregation increased. WCS increased by 15.82% from 1990 to 2020, it is mainly derived from forest landscape, which contributes more than 91% to WCS. The effects of landscape patterns on WCS were spatially heterogeneous. The mean patch density and largest patch index positively affected WCS in 66.80%–82.88% and 64.35%–72.42% of the regions, respectively, whereas the mean patch area negatively impacted WCS in 66.64%–82.41% of the regions. Decision makers can promote ecosystem management measures that are suitable for specific conditions based on the spatial differences of the effects of landscape patterns on WCS.

Influence of roads on space use by European hares in different landscapes

ContextRoads are ubiquitous in human inhabited landscapes, and can impact animal movement and population dynamics, due to barrier effects, road mortality, but also by providing resources at road verges. Thus, we need a better understanding of how roads, in interaction with seasonal changes in habitat structure, affect space use and habitat selection of the animals that persist in these landscapes.ObjectivesHere, we used the European hare (Lepus europaeus) as model species to investigate how human-induced changes in landscape composition—measured as road density, land cover type, and field size—affect home range location, seasonal habitat selection and road crossings, which are likely to correlate with wildlife-vehicle collision risk.MethodsWe collected > 240,000 GPS positions of 90 hares from three populations (one in Denmark and two in Germany) that differed regarding agricultural intensification and road density. Using this data, we analyzed home range location and habitat selection (using step-selection functions) in relation to roads, habitat composition, and seasonality, and quantified how these factors affected road crossings by hares.ResultsIn comparatively more heterogeneous landscapes, hares established home ranges in areas with lower road densities compared to the surrounding area, but not in more simple landscapes. Moreover, hares generally avoided main roads and selected for minor roads during the vegetation growth seasons, especially in areas with comparatively less heterogeneous habitat structure. Hares crossed more main roads when moving greater distances, with movement distances being comparatively larger in simpler landscapes.ConclusionsOur findings emphasize that it is important to distinguish between road types, as different roads can have different impacts on animals (e.g., small roads providing foraging opportunities via roadside vegetation and large roads being avoided). Moreover, animals in comparatively more heterogeneous landscapes are better able to adjust their habitat selection to avoid main roads than animals inhabiting simpler landscapes. More generally, homogenous landscapes increase the space use requirements of animals, leading to increased probability of road crossings, which in turn might affect population dynamics via increased road mortality risk.

Interpreting Mangrove Habitat and Coastal Land Cover Change in the Greater Bay Area, Southern China, from 1924 to 2020 Using Historical Aerial Photos and Multiple Sources of Satellite Data

Coastal habitat dynamics and ecosystem function in response to human-induced disturbance, especially urbanization, are of increasing concern. However, how changes in landscape composition as well as habitat quantity and quality may affect the long-term sustainability of rapidly urbanizing coasts remains unclear. This study aimed to quantify the extent, change rate, patterns, change process and interrelationships of mangrove habitats, impervious surfaces, and other land cover types in Deep Bay in the Guangdong-Hong Kong-Macau Greater Bay Area (GBA), China, the world’s largest megalopolis, from 1924 to 2020. We processed historical aerial photos (1924–2020) and multiple sources of satellite data (1973–2020) for different types of land cover mapping. Post-classification analysis, including correlation analysis and change detection analysis, was conducted based on the long time-series land cover classification results. Mangrove habitats increased in Deep Bay from 1924 to 2020, except for a large area decrease from 1954 to 1964 due to the construction of tidal aquaculture ponds. Mudflat areas contributed most to the expansion of mangrove habitats of about 275 ha from 1987 to 2020. During this period, reclamation and urbanization for the construction of the megacity of Shenzhen turned large areas of water and mudflat (about 4000 ha) on the northern shore into impervious surface and urban vegetation. Overall, the landscape pattern of mangrove habitats in Deep Bay showed increasing connectivity and decreasing degree of fragmentation from 1987 to 2020. These changes have significant implications for the ecosystem services, e.g., supporting migratory waterbirds, supported by these wetlands.

Intermediate human activities maximize dryland ecosystem services in the long-term land-use change: Evidence from the Sangong River watershed, northwest China

Human activities cause widespread changes in landscape composition, which can affect ecosystem services produced by these landscapes. It is usually believed that ecosystem services can be maximized only when we eliminate all human activities. However, this belief is not the case, at least in dryland ecosystems. Here, a gradient of human activity intensity was used to investigate changes in the value of ecosystem services over 30-years of land-use change between 1990 and 2020 in the arid Sangong River watershed of northwest China. Spatial analyses were performed to determine how the value of dryland ecosystem services changed with human activity intensity. Stepwise regressions and linear programming models were also performed to examine how to optimize the value of ecosystem services (i.e., regulating services, provisioning services, supporting services, and cultural services). We found that landscapes of the Sangong River watershed became increasingly fragmented and that human activities gradually intensified, but the value of ecosystem services fluctuated rather than linearly decreasing over the past 30 years. Specifically, a unimodal relationship was observed between human activities and ecosystem services. The peak value of ecosystem services was 5799 USD ha−1 yr−1 under intermediate human activity intensity (i.e., human footprint index ranged from 0.2 to 0.4 at a scale of one). Gross domestic product (GDP) per capita, population, and water consumption were the three most important driving factors of human activities and ecosystem services. Our results suggest that intermediate human activities may maximize dryland ecosystem services in long-term land-use change at the watershed scale, and highlight the importance of regulating economic development, population, and water consumption for the management of dryland ecosystem services.

Using transition matrices to assess the spatio‐temporal land cover and ecotone changes in fluvial landscapes from historical planimetric data

AbstractChange detection approaches based on historical maps are frequently used in fluvial geomorphology to reconstruct long‐term river trajectories and evaluate the level of functional degradation. On this basis, achievable rehabilitation goals may also be addressed. However, most of these studies explore the changes of land cover over time only through changes in the landscape composition, which is nevertheless not sufficient to assess accurately the river responses to natural and/or man‐made disturbances. In this study, we present that transition matrices and new metrics derived from this approach can be used to evaluate the land cover and ecotone area changes at multispatial scales on a 6 km long reach of the Upper Rhine. This study was based on the historical maps of 1828, 1838 and 1872 and using Open Street Map (OSM) for 2021. Our approach was targeting to assess (i) the composition and configuration of a fluvial landscape over time from pixel to landscape scale, (ii) the accurate location of land cover changes, their nature and their intensities, and (iii) the location, nature and diversity of the ecotone areas and their spatial complexities over time. The results showed that (i) the absence of changes in landscape composition over time cannot be interpreted as stability in the fluvial landscape in all cases, (ii) transition matrices are robust tools to face interpretation biases caused by conventional approaches based on landscape composition, because they allow us to trace the changes of each element of the transformed landscape elements. From this study, we indicate that the Rhine regulation induced a habitat and ecotone homogenization following the river correction works, which was exacerbated by the Rhine by‐passing, mainly due to the degradation of lateral connectivity between the main channel and the floodplain and global loss of the hydrosystem functionality.

The expansion of olive groves is reducing habitat suitability for the Great Bustard Otis tarda and the Little Bustard Tetrax tetrax in Southern Spain: could Important Bird Areas (IBAs) reduce this expansion?

AbstractOlive groves in the Mediterranean basin have undergone a tremendous increase during the last two decades, with most of the new olive groves being planted on arable land. This conversion may affect habitat suitability for steppe birds, which are associated with arable land and other open-land habitats, such as natural pastures. In this work, we evaluate the presence of new olive groves in the distribution of the Great Bustard Otis tarda and the Little Bustard Tetrax tetrax in Southern Spain (the largest olive oil production zone in the world), and we compare the percentage of different land uses in 2000 and 2018 using data provided by the Corine Land Cover. From 2000 to 2018, new olive groves occupied 2.14 and 2.61% of the distribution areas of the Great Bustard and the Little Bustard, respectively. The decrease in arable land and the increase in permanent crops were the main drivers of the landscape composition changes during the study period. The fragmentation index of arable land was higher in 2018 than 2000. These changes in the landscape suggest a decrease in habitat availability and suitability for steppe birds that could affect the distribution and abundance of their populations. Moreover, there were no differences in the proportion of new olive groves planted inside and outside the limits of Important Bird Areas (IBAs) from 2000 to 2018, which were created to protect these steppe birds, thus suggesting that the management policy of the IBAs should be reviewed to prevent harmful land-use changes.

Spatial and Temporal Changes of Landscape Patterns and Their Effects on Ecosystem Services in the Huaihe River Basin, China

Landscape pattern changes caused by human activities are among the most important driving factors affecting ecosystem spatial structure and components, and significantly impact ecosystem services. Understanding the relationship between landscape patterns and ecosystem services is important for improving regional conservation and establishing ecosystem management strategies. Taking the Huaihe River Basin as an example, this study used land-use data, meteorological data, and topographic data to analyze the spatial and temporal changes in landscape patterns via landscape transfer matrix and landscape indices, and measured four ecosystem services (water retention, soil retention, carbon storage, and biodiversity conservation) with the InVEST models. Furthermore, correlation analysis and global spatial autocorrelation coefficient were used to analyze the impact of landscape pattern changes on ecosystem services. The results showed grassland and farmland areas had continuously decreased, while built-up land and affected water had significantly increased. Landscape fragmentation was reduced, the connectivity between patches was weakened, landscape heterogeneity, evenness, and patch irregularity were increased. Changes in landscape composition and configuration have affected the ecosystem services of the Huaihe River Basin. The reduction in grassland areas and the increase in built-up land areas have significantly reduced the capacity for soil retention, carbon storage, and biodiversity conservation. Spatially, regions with low landscape fragmentation and high patch connectivity had a higher water retention capacity and biodiversity conservation, while soil retention and carbon storage were opposite. Temporally, reduction of landscape fragmentation and increase of patch shape irregularity had a negative effect on water retention, carbon storage, and biodiversity conservation, while soil retention was not sensitive to these changes. The findings in this paper promote an understanding of the relationship between landscape patterns and ecosystem services on a large scale and provide theoretical guidance for ecosystem management and protection planning in the Huaihe River Basin, China.

Spatiotemporal Impact of Urbanization on Urban Heat Island and Urban Thermal Field Variance Index of Tianjin City, China

The rapid infrastructure development in densely populated areas has had several negative impacts. Increases in urbanization have led to increased LST, and urban ecological systems have been negatively affected. Urban heat islands (UHIs) can be mitigated by understanding how current and future LST phenomena are linked to changes in landscape composition and land use cover (LUC). This study investigated the multi-scale spatial analysis of LUC and LST in Tianjin using remote sensing and GIS data. We used Landsat data from 2005 to 2020 to examine the effects of LUC on LST in urban agglomeration. According to the Urban Thermal Field Variance Index (UTFVI), the city’s ecological evaluation was carried out. Results show that changes in LUC and other anthropogenic activities affect the spatial distribution of LST. For the study years (2004–2009), the estimated mean LST in Tianjin was 25.32 °C, 26.73 °C, 27.62 °C, and 27.93 °C. Between LST and urban areas with other infrastructures, and NDBI, significant positive correlation values were found about 0.53, 0.48, and 0.76 (p < 0.05), respectively. Temperatures would almost certainly increase by 3.87 °C to 7.26 °C as a result of decreased plant cover and increased settlements. These findings strongly imply a correlation between LST and the vegetation index. Between 2005 and 2020, the anticipated increase in LST of 3.39 °C is expected to harm urban environmental health. This study demonstrates how Tianjin and other cities can achieve ecological sustainability.

Assessing the impact of grassland management on landscape multifunctionality

Land-use intensification has contrasting effects on different ecosystem services, often leading to land-use conflicts. While multiple studies have demonstrated how landscape-scale strategies can minimise the trade-off between agricultural production and biodiversity conservation, little is known about which land-use strategies maximise the landscape-level supply of multiple ecosystem services (landscape multifunctionality), a common goal of stakeholder communities.We combine comprehensive data collected from 150 German grassland sites with a simulation approach to identify landscape compositions, with differing proportions of low-, medium-, and high-intensity grasslands, that minimise trade-offs between the six main grassland ecosystem services prioritised by local stakeholders: biodiversity conservation, aesthetic value, productivity, carbon storage, foraging, and regional identity. Results are made accessible through an online tool that provides information on which compositions best meet any combination of user-defined priorities (https://neyret.shinyapps.io/landscape_composition_for_multifunctionality/).Results show that an optimal landscape composition can be identified for any pattern of ecosystem service priorities. However, multifunctionality was similar and low for all landscape compositions in cases where there are strong trade-offs between services (e.g. aesthetic value and fodder production), where many services were prioritised, and where drivers other than land use played an important role. We also found that if moderate service levels are deemed acceptable, then strategies in which both high and low intensity grasslands are present can deliver landscape multifunctionality. The tool presented can aid informed decision-making by predicting the impact of future changes in landscape composition, and by allowing for the relative roles of stakeholder priorities and biophysical trade-offs to be understood by scientists and practitioners alike.

Isotopic niches of tropical birds reduced by anthropogenic impacts: a 100‐year perspective

The intensification of land‐use changes in tropical forests during the 20th century, mainly caused by deforestation for agricultural uses, had an overwhelming influence on bird assemblages. However, how these historical anthropogenic changes have impacted the habitat use and diet of tropical birds is poorly known. Stable isotope analysis (δ13C and δ15N) can be useful in this regard since it provides information not only on the habitat and food resource use but also insights on the dietary niche of species. Here, we aimed to evaluate whether centenary anthropogenic impacts, mainly caused by changes in landscape composition, have affected the resource and habitat use and isotopic niche width of Neotropical birds in a region that comprises two biodiversity hotspots – the Atlantic Forest and Cerrado in southeastern Brazil. We found that the niche width of all bird guilds (frugivore, granivore, insectivore, nectarivore and omnivore) was largely reduced (28–70%) from the 20th century until recently. This niche width reduction was likely associated with historical anthropogenic impacts (e.g. fragmentation, forest loss and change in agricultural practices), which are responsible for the decrease in the availability of habitat and food resources. Moreover, the mean values of δ15N decreased over the years in all bird guilds, which might be attributed to the expansion of agricultural areas and the increase in the use of synthetic nitrogen‐based fertilizers. All the analyzed species, even though some of them are diet and habitat generalists, were strongly influenced by centenary anthropogenic actions. Our results show the consequences of human‐induced changes in land use on the diet and habitat use of tropical birds that persist in fragmented landscapes, which might compromise their long‐term survival and provide useful information to the conservation strategies of bird assemblages in modern landscapes.

Spatiotemporal patterns and ecological consequences of a fragmented landscape created by damming.

BackgroundDamming disrupts rivers and destroys neighboring terrestrial ecosystems through inundation, resulting in profound and long-lasting impacts on biodiversity and ecosystem processes far beyond the river system itself. Archipelagos formed by damming are often considered ideal systems for studying habitat fragmentation.MethodsHere we quantified the island attributes and landscape dynamics of the Thousand Island Lake (TIL) in China, which is one of the several long-term biodiversity/fragmentation research sites around the world. We also synthesized the major findings of relevant studies conducted in the region to further ecological understanding of damming and landscape fragmentation.ResultsOur results show that the vegetations on islands and the neighboring mainland were both recovering between 1985 and 2005 due to reforestation and natural succession, but the regeneration was partly interrupted after 2005 because of increasing human influences. While major changes in landscape composition occurred primarily in the lakefront areas and near-lakeshore islands, landscape patterns became structurally more complex and fragmented on both islands and mainland. About 80 studies from the TIL region show that the genetic, taxonomic, functional, and phylogenetic diversity on these islands were mainly influenced by island area at the patch scale, but fragmentation per se also affected species composition and related ecological processes at patch and landscape scales. In general, islands had lower species diversity but a steeper species-area relationship than the surrounding mainland. Fragmentation and edge effects substantially hindered ecological succession towards more densely vegetated forests on the islands. Environmental heterogeneity and filtering had a major impact on island biotic communities. We hypothesize that there are multiple mechanisms operating at different spatial scales that link landscape fragmentation and ecological dynamics in the TIL region, which beg for future studies. By focusing on an extensive spatiotemporal analysis of the island-mainland system and a synthesis of existing studies in the region, this study provides an important foundation and several promising directions for future studies.

Developing Species-Age Cohorts from Forest Inventory and Analysis Data to Parameterize a Forest Landscape Model

Simulating long-term, landscape level changes in forest composition requires estimates of stand age to initialize succession models. Detailed stand ages are rarely available, and even general information on stand history often is lacking. We used data from USDA Forest Service Forest Inventory and Analysis (FIA) database to estimate broad age classes for a forested landscape to simulate changes in landscape composition and structure relative to climate change at Fort Drum, a 43,000 ha U.S. Army installation in northwestern New York. Using simple linear regression, we developed relationships between tree diameter and age for FIA site trees from the host and adjacent ecoregions and applied those relationships to forest stands at Fort Drum. We observed that approximately half of the variation in age was explained by diameter breast height (DBH) across all species studied (r2 = 0.42 for sugar maple Acer saccharum to 0.63 for white ash Fraxinus americana). We then used age-diameter relationships from published research on northern hardwood species to calibrate results from the FIA-based analysis. With predicted stand age, we used tree species life histories and environmental conditions represented by ecological site types to parameterize a stochastic forest landscape model (LANDIS-II) to spatially and temporally model successional changes in forest communities at Fort Drum. Forest stands modeled over 100 years without significant disturbance appeared to reflect expected patterns of increasing dominance by shade-tolerant mesophytic tree species such as sugar maple, red maple (Acer rubrum), and eastern hemlock (Tsuga canadensis) where soil moisture was sufficient. On drier sandy soils, eastern white pine (Pinus strobus), red pine (P. resinosa), northern red oak (Quercus rubra), and white oak (Q. alba) continued to be important components throughout the modeling period with no net loss at the landscape scale. Our results suggest that despite abundant precipitation and relatively low evapotranspiration rates for the region, low soil water holding capacity and fertility may be limiting factors for the spread of mesophytic species on excessively drained soils in the region. Increasing atmospheric temperatures projected for the region could alter moisture regimes for many coarse-textured soils providing a possible mechanism for expansion of xerophytic tree species.

Critical ecological thresholds for conservation of tropical rainforest in Human Modified Landscapes

In the tropics, human modified landscapes (HMLs) emerge as potential areas where important levels of biodiversity, ecosystem functions, and services can be conserved. Yet, it is unknown which landscape structures may enable this goal. We studied how tree diversity (SD), aboveground biomass (AGB) and aboveground carbon storage (ACS) change across a gradient of forest-to-agriculture conversion process (0 to ~100%). We addressed following questions: i) How SD, AGB and ACS change with landscape composition and configuration, as the forest-to-agriculture conversion advances? ii) Do such changes depend on the spatial scale of the landscapes, iii) Are there thresholds of forest habitat loss after which SD, AGB and ACS collapse? iv) If so, what explains such response? Changes in landscape composition, but not in configuration, explained the SD, ABG, ACS variability across the deforestation gradient. Percentage of forest cover was the best predictor of such variation, independently the landscape spatial scale. SD declined convexly, showing a critical collapse threshold, as forest loss advanced. AGB and ACS decreased exponentially with a 50% of reduction at ~30% of forest loss. Elimination of several rare species with high contributions to AGB explained the exponential decrease of AGB and ACS. We accord with previous studies targeted in other assemblages and forest trees variables that maintaining >40% of forest is critical for tree diversity conservation. We broaden this estimation by alerting that ecosystem functions (e.g., AGB) and services (e.g., ACS) reduce with deforestation in a faster way than biodiversity. This exemplifies that different ecosystem attributes are affected differentially by deforestation, adding a strong challenge for conservation in HML.

Impacts of Urbanization on the Muthurajawela Marsh and Negombo Lagoon, Sri Lanka: Implications for Landscape Planning towards a Sustainable Urban Wetland Ecosystem

Urban wetland ecosystems (UWEs) play important social and ecological roles but are often adversely affected by urban landscape transformations. Spatio-temporal analyses to gain insights into the trajectories of landscape changes in these ecosystems are needed for better landscape planning towards sustainable UWEs. In this study, we examined the impacts of urbanization on the Muthurajawela Marsh and Negombo Lagoon (MMNL), an important UWE in Sri Lanka that provides valuable ecosystem services. We used remote sensing data to detect changes in the land use/cover (LUC) of the MMNL over a two-decade period (1997–2017) and spatial metrics to characterize changes in landscape composition and configuration. The results revealed that the spatial and socio-economic elements of rapid urbanization of the MMNL had been the main driver of transformation of its natural environment over the past 20 years. This is indicated by a substantial expansion of settlements (+68%) and a considerable decrease of marshland and mangrove cover (−41% and −21%, respectively). A statistical analysis revealed a significant relationship between the change in population density and the loss of wetland due to settlement expansion at the Grama Niladhari division level (n = 99) (where wetland includes marshland, mangrove, and water) (1997–2007: R2 = 0.435, p = 0.000; 2007–2017: R2 = 0.343, p = 0.000). The findings also revealed that most of the observed LUC changes occurred in areas close to roads and growth nodes (viz. Negombo, Ja-Ela, Wattala, and Katana), which resulted in both landscape fragmentation and infill urban expansion. We conclude that, in order to ensure the sustainability of the MMNL, there is an urgent need for forward-looking landscape and urban planning to promote environmentally conscious urban development in the area which is a highly valuable UWE.

Structural implications of traditional agricultural landscapes on the functional diversity of birds near the Korean Demilitarized Zone.

Bird assemblages are sensitive to changes in landscape composition and the environment, such as those that result from drought. In this study, the relationship between landscape composition and avian functional diversity in traditional agricultural ecosystems in the Civilian Control Zone (CCZ) of Korea was examined. In addition, the resilience of biodiversity to changes in landscape elements resulting from drought conditions was investigated. The traditional agricultural landscape (TAL) of the sites studied was divided into three types: TAL 1 had a high proportion of rice paddies, TAL 2 included large forest areas, and TAL 3 represented areas with drylands. Of these, TAL 1 showed the highest species richness and functional richness, but these measures were most vulnerable to drought. Meanwhile, TAL 2 showed that the bird communities were more tolerant under drought event. This study shows that to conserve and enhance the diversity of birds in traditional agricultural landscapes of Northeast Asia, active management of forest areas is needed to protect bird populations. In addition, commercial pressures to develop this area will require urgent biodiversity conservation plans to protect the unique biodiversity of the Korean CCZ. This study thus provides landscape management guidance for conservation planning.

Three decades of land-use and land-cover change in mountain regions of the Brazilian Atlantic Forest

Mountain regions are key hotspots for biodiversity conservation and for provisioning ecosystem services. Containing fragile ecosystems and home to millions of inhabitants, mountains are also places of great value for tourism, cultural practices and endemic species. In this paper, we developed the first multitemporal land-use and land-cover assessment of mountain regions within the Brazilian Atlantic Forest (BAF), the most endangered Brazilian tropical biome. The study used spatial thematic mapping for 1985, 2001, and 2018 to understand changes in landscape composition, patterns of change in patch metrics of natural vegetation cover, and correlations between human population and natural vegetation. Change detection techniques, landscape metrics and statistical tests (e.g., Kruskal-Wallis) were applied. We found that landscape composition did not change at significant levels over the 34 years (1985–2018), but that intense exchange between natural vegetation and agriculture creates a shifting mosaic steady-state. Additionally, natural vegetation loss was 13-fold lower within mountains than in other areas of the BAF biome, which indicates lower human-induced change in mountain regions. Urban and rural population (number of inhabitants) showed positive correlation with natural vegetation at municipality level indicating higher presence of population in municipalities with large extents of natural vegetation. Analysis demonstrated that the study region was under lower population pressure and urban growth compared to other areas and had kept large extents of natural vegetation within large patches, different to what is observed at biome level. However, telecoupling processes may result in indirect land changes in mountain regions of the BAF biome. Our results indicate that mountains play a key role in conserving the remnants of the BAF.