Influence Of Landscape Configuration Research Articles

Dynamics and fate of blue carbon in a mangrove\u2013seagrass seascape: influence of landscape configuration and land-use change

ContextSeagrass meadows act as efficient natural carbon sinks by sequestering atmospheric CO2 and through trapping of allochthonous organic material, thereby preserving organic carbon (Corg) in their sediments. Less understood is the influence of landscape configuration and transformation (land-use change) on carbon sequestration dynamics in coastal seascapes across the land–sea interface.ObjectivesWe explored the influence of landscape configuration and degradation of adjacent mangroves on the dynamics and fate of Corg in seagrass habitats.MethodsThrough predictive modelling, we assessed sedimentary Corg content, stocks and source composition in multiple seascapes (km-wide buffer zones) dominated by different seagrass communities in northwest Madagascar. The study area encompassed seagrass meadows adjacent to intact and deforested mangroves.ResultsThe sedimentary Corg content was influenced by a combination of landscape metrics and inherent habitat plant- and sediment-properties. We found a strong land-to-sea gradient, likely driven by hydrodynamic forces, generating distinct patterns in sedimentary Corg levels in seagrass seascapes. There was higher Corg content and a mangrove signal in seagrass surface sediments closer to the deforested mangrove area, possibly due to an escalated export of Corg from deforested mangrove soils. Seascapes comprising large continuous seagrass meadows had higher sedimentary Corg levels in comparison to more diverse and patchy seascapes.ConclusionOur results emphasize the benefit to consider the influence of seascape configuration and connectivity to accurately assess Corg content in coastal habitats. Understanding spatial patterns of variability and what is driving the observed patterns is useful for identifying carbon sink hotspots and develop management prioritizations.

The Mouths of Estuaries Are Key Transition Zones that Concentrate the Ecological Effects of Predators

Whether and how landscape context and habitat traits combine to shape animal assemblages and the rate and distribution of ecological functions remains unresolved in many aquatic settings. Saltmarshes are one such ecosystem in which these considerations are frequently acknowledged as important, but quantitative studies of these effects are rare, especially for ecological functions. In this study, the influence of landscape configuration and habitat traits on the composition of fish assemblages and rates of predation were quantified around 30 saltmarshes in three estuaries (i.e., 10 per estuary) in eastern Australia. Fish assemblages were surveyed using unbaited underwater video cameras, and predation was quantified using videoed “Squidpop” predation assays at 10 sites at each saltmarsh. The structure of fish assemblages was best explained by the estuary in which saltmarsh was located, the proximity of sites to estuary mouth, and the area of nearby saltmarsh and mangroves. Predation was dominated (90% of total predation events) by yellowfin bream Acanthopagrus australis (Sparidae), and so rates of predation correlated positively with yellowfin bream abundance. Predation peaked in the lower reaches of estuaries at saltmarshes with lower vegetation cover. These findings suggest that the mouths of estuaries might function as key transition zones that concentrate prey, the products of trophic relay, and the ecological effects of predators near the estuarine-sea interface.

Seasonal contrast of the dominant factors for spatial distribution of land surface temperature in urban areas

Urban heat island (UHI) has become an urban eco-environmental problem globally. Land surface temperature (LST) is widely used to quantify UHI. This study used Shenzhen, a southern coastal city in China, as an example to explore the relationship between spatial variation of LST in different seasons and the influencing factors in five dimensions, integrating the methods of ordinary least-squares regression, stepwise regression, all-subsets regression, and hierarchical partitioning analysis. The results showed that the most important factor affecting spatial heterogeneity of LST in summer was the normalized difference build-up index (53.62%, for contributing rate), whereas in the transition season the most important factor was the normalized difference vegetation index (NDVI) (47.84%). In winter the construction land percentage and NDVI (26.84% and 25.56%, respectively) were the most influential. Artificial surface and green space had a dominant effect on LST spatial differentiation. Landscape configuration and diversity were not the dominant influencing factors in summer or in the transition season. Furthermore, the independent contribution rate of the Shannon diversity index (SHDI) reached 8.79% in the transition season, while in winter, the independent contribution rates of SHDI and the landscape shape index were 8.52% and 3.45%, respectively. The influence of landscape diversity and configuration factors tended to increase as LST reduced, while the contribution rate of the important factors such as artificial surface and green space decreased significantly. These relationships indicate that the influence of landscape configuration and diversity factors on LST is relatively weak, and can be easily concealed by the influence of landscape components, especially when the spatial variation of LST is not strong. These findings can help to develop UHI adaptation strategies based on local conditions.

Application of partial least squares regression in detecting the important landscape indicators determining urban land surface temperature variation

Revealing the interaction between landscape pattern and urban land surface temperature (LST) can provide insight into mitigating thermal environmental risks. However, there is no consensus about the key landscape indicators influencing LST. This study sought to identify the key landscape indicators influencing LST considering a large number of landscape pattern variables and multiple scales. This study applied ordinary least squares regression and partial least squares regression to explore a combination of landscape metrics and identify the key indicators influencing LST. A total of 49 Landsat images of the main city of Shenzhen, China were examined at 13 spatial scales. The landscape composition indicators derived from biophysical proportion, a new metric developed in this study, more effectively determined LST variation than those derived from land cover proportion. Area-related landscape configuration indicators independently characterized LST variation, but did not give much more new information beyond that given by land cover proportion. Shape-related landscape configuration indicators were effective in combination with land cover proportion, but their importance was uncertain when temporal and spatial scales varied. The influence of landscape configuration on LST exists but should not be overestimated. Comparison of numerous variables at multiple spatiotemporal scales can help identify the influence of multiple landscape characteristics on LST variation.

Modelling the impacts of agriculture in mixed-use landscapes: a review and case study involving two species of dabbling ducks

This study synthesizes evidence from three separate surveys of American Black Duck and Mallard breeding habitat usage to quantify the effects of agriculture at the landscape scale. To assess duck breeding activity in agricultural landscapes within the Canadian maritimes in order to measure the overall impact of agricultural land use, the response to particular agricultural activities, and the influence of landscape configuration. Models, constructed using a long-term census (SURVEY1), were used to predict habitat selection for two other independent surveys (SURVEY2, SURVEY3). Predictions incorporated information about wetland area and diversity, as well as anthropogenic factors, allowing subsequent analyses to focus on the remaining residual error attributable to agricultural effects. SURVEY2 results demonstrated that the proportion of active agriculture is an important indicator of the severity of human disturbance, yielding threshold estimates of 39% for Mallards and 60% for Black Ducks, with an overall average of 50%. Agricultural conversion beyond these thresholds deterred breeding ducks independently of other factors. SURVEY3 land cover information demonstrated that the presence of cropland intensified this deterrence effect, even at levels as low as 10%. Woodland cover (in excess of 30%) was important for both species, but its configuration was not. In addition to quantifying threshold effects, this study reaffirms that woodland is an important part of the maritime landscape matrix, and contributes positively to habitat diversity in mixed use, moderate intensity agricultural regions. Wetland restoration in agricultural landscapes should monitor and promote less crop-intensive, mixed-use practices.

Landscape configuration is the primary driver of impacts on water quality associated with agricultural expansion

Corporations and other multinational institutions are increasingly looking to evaluate their innovation and procurement decisions over a range of environmental criteria, including impacts on ecosystem services according to the spatial configuration of activities on the landscape. We have developed a spatially explicit approach and modeled a hypothetical corporate supply chain decision representing contrasting patterns of land-use change in four regions of the globe. This illustrates the effect of introducing spatial considerations in the analysis of ecosystem services, specifically sediment retention. We explored a wide variety of contexts (Iowa, USA; Mato Grosso, Brazil; and Jiangxi and Heilongjiang in China) and these show that per-area representation of impacts based on the physical characterization of a region can be misleading. We found two- to five-fold differences in sediment export for the same amount of habitat conversion within regions characterized by similar physical traits. These differences were mainly determined by the distance between land use changes and streams. The influence of landscape configuration is so dramatic that it can override wide variation in erosion potential driven by physical factors like soil type, slope, and climate. To minimize damage to spatially-dependent ecosystem services like water purification, sustainable sourcing strategies should not assume a direct correlation between impact and area but rather allow for possible nonlinearity in impacts, especially in regions with little remaining habitat and highly variable hydrological connectivity.

Sugar maple tree canopies as reservoirs for arthropod functional diversity in forest patches across a fragmented agricultural landscape in southern Quebec, Canada

ABSTRACTForest fragments and their tree canopies may act as important reservoirs for biodiversity, but their role in supporting diversity is poorly understood in the context of their spatial arrangement. We examine the influence of landscape configuration and location within forest patches (e.g. canopy, edge or patch interior) on patterns of arthropod biodiversity associated with sugar maple trees across an agricultural landscape in southern Quebec (Canada). We sampled arthropods from sugar maples in 20 sugar maple–beech-dominated forest patches that varied in size and isolation from other forest patches. Within each patch, arthropods were collected in the interior, edge and canopy of patches over two seasons. Size and isolation of forest patches did not affect arthropod family or functional group diversity, but patch canopies supported a higher diversity than understories. Both configuration and within-patch location affected taxonomic and functional composition of arthropods. For example, phytophages and saprophages were found in greatest abundance in canopies and large patches, while entomophages were in highest abundance in interiors. We conclude that even in relatively small (e.g. 5–10 ha) forest patches, canopies are providing critical reservoirs for arthropod diversity, and draw our attention to the conservation value of small patches in fragmented forest landscapes.

The influence of landscape configuration and environment on population genetic structure in a sedentary passerine: insights from loci located in different genomic regions

The study of the factors structuring genetic variation can help to infer the neutral and adaptive processes shaping the demographic and evolutionary trajectories of natural populations. Here, we analyse the role of isolation by distance (IBD), isolation by resistance (IBR, defined by landscape composition) and isolation by environment (IBE, estimated as habitat and elevation dissimilarity) in structuring genetic variation in 25 blue tit (Cyanistes caeruleus) populations. We typed 1385 individuals at 26 microsatellite loci classified into two groups by considering whether they are located into genomic regions that are actively (TL; 12 loci) or not (NTL; 14 loci) transcribed to RNA. Population genetic differentiation was mostly detected using the panel of NTL. Landscape genetic analyses showed a pattern of IBD for all loci and the panel of NTL, but genetic differentiation estimated at TL was only explained by IBR models considering high resistance for natural vegetation and low resistance for agricultural lands. Finally, the absence for IBE suggests a lack of divergent selection pressures associated with differences in habitat and elevation. Overall, our study shows that markers located in different genomic regions can yield contrasting inferences on landscape-level patterns of realized gene flow in natural populations.

Spatial variability of particle size fractions of an Oxisol cultivated with conilon coffee

Information on the spatial distribution of particle size fractions is essential for use planning and management of soils. The aim of this work to was to study the spatial variability of particle size fractions of a Typic Hapludox cultivated with conilon coffee. The soil samples were collected at depths of 0-0.20 and 0.20-0.40 m in the coffee canopy projection, totaling 109 georeferentiated points. At the depth of 0.2-0.4 m the clay fraction showed average value significantly higher, while the sand fraction showed was higher in the depth of 0-0.20 m. The silt showed no significant difference between the two depths. The particle size fractions showed medium and high spatial variability. The levels of total sand and clay have positive and negative correlation, respectively, with the altitude of the sampling points, indicating the influence of landscape configuration.

The influence of landscape configuration upon patterns of sediment storage in a highly connected river system

Orthoimages are used to analyze the influence of valley width, channel slope, and the area of landslides that deliver sediment to valley floors upon the downstream pattern of sediment storage in the Liwu basin, eastern Taiwan. Confined valley settings dominate this steep, deeply dissected, uplifting mountainous basin. Although they occupy 82% of the whole channel network, sediment storage is limited in these reaches. Partly confined valley settings are restricted to relatively short reaches of two tributary systems. Over 95% of sediment storage in the Liwu River is found within the short alluvial section of laterally unconfined valley close to the river mouth. Lateral bars are the primary features associated with sediment storage in confined reaches (54% in total volume), while floodplains dominate the partly confined and laterally unconfined reaches (95% in total volume). Downstream patterns of sediment storage are controlled primarily by valley confinement (i.e., valley width) and landscape configuration. Channel slope and locations of contemporary landslides are not key determinants of sediment storage patterns. Sediment accumulation at confluence zones is not determined by the catchment area of tributaries or by landslide area; rather, it is determined by valley confinement of the trunk stream at the confluence and the associated downstream sequence of river types. Sediment conveyance is very effective within this highly connected river system.

Regional assessment on influence of landscape configuration and connectivity on range size of white-tailed deer

Variation in the size of home range of white-tailed deer (Odocoileus virginianus) has broad implications for managing populations, agricultural damage, and disease spread and transmission. Size of home range of deer also varies seasonally because plant phenology dictates the vegetation types that are used as foraging or resting sites. Knowledge of the landscape configuration and connectivity that contributes to variation in size of home range of deer for the region is needed to fully understand differences and similarities of deer ecology throughout the Midwest. We developed a research team from four Midwestern states to investigate how size of home range of deer in agro-forested landscapes is influenced by variations in landscape characteristics that provide essential habitat components. We found that for resident female deer, annual size of home range in Illinois (mean = 0.99 km2), Michigan (mean = 1.34 km2), Nebraska (mean = 1.20 km2), and Wisconsin (mean = 1.47 km2) did not differ across the region (F 3,175 = 0.42, P = 0.737), but differences between agricultural growing and nongrowing periods were apparent. Variables influencing size of home range included: distance to forests, roads, and urban development from the centroid of deer home range, and percent of crop as well as four landscape pattern indices (contrast-weighted edge density, mean nearest neighbor, area-weighted mean shape index, and patch size coefficient of variation). We also identified differences in model selection for four landscapes created hierarchically to reflect levels of landscape connectivity determined from perceived ability of deer to traverse the landscape. Connectivity of selected forested regions within agro-forested ecosystems across the Midwest plays a greater role in understanding the size of home ranges than traditional definitions of deer habitat conditions and landscape configuration.

Modeling of continuous-time land cover change using satellite imagery: an application from North Carolina

This study examines the determinants of urbanized area across a 10,000-mile square swath in central North Carolina, an area undergoing extensive conversion of forest and agricultural land. We model the temporal and spatial dimensions of these landscape changes using a database that links five satellite images spanning 1976–2001 to a suite of socioeconomic, ecological and GIS-created explanatory variables. By specifying the complementary log-log derivation of the proportional hazards model, we employ a methodology for modeling a continuous time process—the conversion of land to impervious surface—using discrete-time satellite data. Spatial hypotheses are tested using several variables derived from the imagery that measure the landscape configuration surrounding a pixel. Empirical results confirm the significance of several determinants of urbanization identified elsewhere in the literature, including proximity to roads and population density, but also suggest that the parameterization of these variables is biased when the influence of landscape configuration is unaccounted for. We conclude that the inclusion of spatial pattern metrics significantly improves both the explanatory and predictive power of the estimated model of urbanization.