Landscape Ecology最新文献

Context

Biotic resource exploitation is a critical determinant of species’ distributions. However, quantifying resource exploitation patterns through space and time can be difficult, complicating their incorporation in spatial ecology studies. Therefore, understanding the local drivers of spatial patterns of resource exploitation may contribute to better large-scale species distribution models.

Objectives

We investigated (1) how the resource exploitation patterns of two trophic interactions (plant–insect) are explained by insect behaviour, resource aggregation, and potential insect-insect interactions. We also analyzed how (2) resource patch size and (3) resource accessibility in a heterogeneous landscape affected host exploitation patterns.

Methods

We quantified nectar robbing by insects in the genus Bombus (bumblebees) and seed predation by Brachypterolus vestitus larvae (Antirrhinum beetle) on Antirrhinum majus L. (wild snapdragons) in the Pyrenees Mountains, Catalonia, Spain. We tested hypotheses about resource exploitation by integrating spatial analyses at multiple scales.

Results

Both trophic interactions were aggregated, explained by the aggregation of their resource. At some scales, nectar robbing is more aggregated than the resource. Trophic interaction abundance is proportional to resource patch size, following the ideal free distribution model. Landscape features do not explain the locations exploited. Nectar robbing and seed predation occur together more often than expected.

Conclusions

Our findings suggest that multiple biotic and ecological spatial factors may simultaneously affect resource exploitation at a local scale. These findings should be considered when developing agricultural projects, management plans and conservation policies.

Context

Abandonment of cultural landscape practices has had a notable impact on grasslands and domestic livestock that depend on them. This affects the prerequisites for sustainable transitions of cultural landscapes, which combine traditional livelihoods and novel ones like tourism.

Objectives

The aims of this study were to explore (1) the long-term temporal dynamics of grassland and livestock in a regional gradient from coastal to inland landscapes in Norway and (2) the temporal development of tourism types among regions.

Methods

Using three regions as case studies, with 62 municipalities, we analyzed (1) the temporal dynamics of grassland and livestock using agricultural census data from 1918 to 1999 and (2) two tourism types. Kruskal–Wallis and ANOVA were used to examine whether the relative changes in grassland areas and livestock units, respectively, differed significantly among regions. A PCA was conducted to explore relationships between grassland and livestock types. The proportions of tourist categories were compared.

Results

The grassland area and thematic resolution of census data declined over time. Grassland areas correlated with domestic livestock units. Multivariate analysis explained 68% of the variation in grassland and livestock types among municipalities. There was a notable increase in the number of tourists, with summer tourism dominating where the cultural landscape was well conserved.

Conclusions

Our study underscores the importance of integrating regional historical trajectories for the conservation and use of valuable cultural landscapes, thereby providing sustainable transitions that combine traditional livelihoods and new types as tourism. Additional in-depth studies are needed to understand the detailed drivers of these changes.

Context

Ecosystem services are fundamental for the well-being of residents and are an important basis for making regional sustainable development decisions. Existing studies mainly capture ecosystem services perceived by residents through questionnaires, or quantify the provision of regional ecosystem services through economic evaluation and biophysical evaluation. However, the discrepancy between model calculations and residents' perceptions remains lacking.

Objectives

Rapidly urbanizing watersheds can serve as a prime example for exploring the differences in ecosystem service outcomes between the two perspectives.

Methods

In this study, we quantified the potential supply of nine ecosystem services and residents' perceptions of these services in the Guanting Reservoir basin through biophysical modelling and questionnaire surveys. We then analyzed the discrepancies between the two perspectives through the Wilcoxon signed-rank test.

Results

The results showed that among the vast majority of the population, half of the nine ecosystem services exhibited significant differences in comparisons between perceived values and model-calculated ones. The differences were more prominent for regulating and supporting services among urban residents, while for provisioning and cultural services among rural residents.

Conclusions

These differences highlight the necessity to consider quantitative results from diverse perspectives as well as on the benefits of different groups of interest. In rapidly urbanizing watersheds, infrastructure should be reinforced in rural areas to enhance rural residents’ accessibility of ecosystem services. With regard to urban areas, particular attention should be directed towards changes in regulating and supporting services.

Purpose

Habitat connectivity is integral to current biodiversity science and conservation strategies. Originally, the connectivity concept stressed the role of individual movements for landscape-scale processes. Connectivity determines whether populations can survive in sub-optimal patches (i.e., source-sink effects), complete life cycles relying on different habitat types (i.e., landscape complementation), and benefit from supplementary resources distributed over the landscape (i.e., landscape supplementation). Although the past decades have witnessed major improvements in habitat connectivity modeling, most approaches have yet to consider the multiplicity of habitat types that a species can benefit from. Without doing so, connectivity analyses potentially fail to meet one of their fundamental purposes: revealing how complex individual movements lead to landscape-scale ecological processes.

Methods

To bridge this conceptual and methodological gap, we propose to include multiple habitat types in spatial graph models of habitat connectivity, where nodes traditionally represent a single habitat type. Multiple habitat graphs will improve how we model connectivity and related landscape ecological processes, and how they are impacted by land cover changes.

Results

In three case studies, we use these graphs to model (i) source-sink effects, (ii) landscape supplementation, and (iii) complementation processes, in urban ecosystems, agricultural landscapes, and amphibian habitat networks, respectively. A new version of the Graphab open-source software implements the proposed approach.

Conclusion

Multiple habitat graphs help address crucial conservation challenges (e.g., urban sprawl, biological control, climate change) by representing more accurately the dynamics of populations, communities, and their interactions. Our approach thereby extends the ecologist’s toolbox and aims at fostering the alignment between landscape ecology theory and practice.

Context

The urban landscape plays a crucial role in achieving sustainability goals and aspiring to a zero-emission future. Effective carbon mitigation strategies need a spatially explicit and life-cycle analysis of building emissions, detailed mapping highlights the geographical distribution and specific characteristics of buildings, enabling precise identification and targeted management of emission sources.

Objectives

This study aims to create a framework that reveals the spatial and temporal dimensions of building carbon emissions at each stage of their life cycle.

Methods

We developed a comprehensive approach for carbon accounting in buildings. This framework captures spatiotemporal carbon emission patterns across various building types, considering material, energy, and waste flows. It also identifies potential mitigation strategies within the urban building landscape.

Results

Applying this framework to a case study in Shenzhen, we observed a fluctuating increase in total carbon emissions, peaking at 201.5 Mt in 2016 and subsequently declining. Embodied emissions dominated before the twenty-first century, while operational emissions became significant afterward. Spatially, emissions hotspots concentrated in central urban districts, expanding outward, with residential buildings contributing the most. Scenario analysis revealed that extending building lifetimes is a key strategy for mitigating embodied carbon, while improving energy efficiency and adopting clean energy work well together to reduce operational carbon.

Conclusions

Mapping the spatiotemporal patterns of carbon emissions throughout a building’s lifespan can assist urban planners and policymakers in formulating targeted strategies for carbon reduction, thereby enhancing urban sustainability.

Context

Small carnivores are declining globally due to a complex suite of threats. Conservation of these species requires an understanding of their distributions and potential responses to future land-use and climate change.

Objectives

We modelled species-environment relationships of swift fox (Vulpes velox), a species of concern across their range. We developed spatial projections of current and future distribution to aid in conservation planning.

Methods

We assembled swift fox occurrence data from managers and community science sources to develop ensemble distribution models. In addition to landscape and climatic predictors, we developed a model of red fox distribution to represent effects of competition. We forecasted spatial predictions into the year 2070 under two climate change scenarios representing high (SSP 5–8.5) and low (SSP 1–2.6) emissions scenarios.

Results

Percent cover by grassland, mean annual precipitation, and minimum temperature of the coldest quarter were the three most important variables for swift fox distribution. Current suitable habitat for swift fox extends across 16 North American states and provinces. Future projections of swift fox distribution suggest an overall increase in area of swift fox suitable habitat under both emissions scenarios of > 56.9%, though patterns of gain and loss vary spatially.

Conclusions

The expansion of suitable habitat in future scenarios reflects swift fox adaptability to multiple land uses in a period following multi-organizational conservation efforts. Our spatial projections can be used in conservation planning and can serve as a case study of a small carnivore species likely to recover under future change scenarios provided that threats are addressed and landscape-scale conservation efforts continue.

Context

Large carnivores have faced severe extinction pressures throughout Europe during the last centuries, where human-induced disturbances reached unprecedented levels. In the late twentieth century, the Cantabrian brown bear population was on the verge of extinction, due to poaching. Yet, the end of the last century was a turning point for this population. Presence data on the western Cantabrian subpopulation was collected since the beginning of the century and insights provided by this long-term monitoring may be useful for brown bear conservation.

Objectives

Here, we aim to: (i) identify the landscape features relevant to bears’ recovery; and (ii) understand if and how the landscape use patterns by bears changed over time.

Methods

We tested the influence of landscape structure (i.e., composition and configuration) on bear occurrence patterns using MAXENT in three periods representative of land cover change.

Results

Despite variation across the 19-year monitoring period, brown bears were more often detected near broad-leaf forests and bare rock areas and at lower to intermediate altitudes, but avoided arable lands, permanent crops, and burnt areas. Human population density or distance to roads—often used for modelling habitat suitability for Cantabrian brown bears—were not identified as relevant variables for this brown bear subpopulation. Artificial areas were identified as relevant landscape features, but not as disturbance.

Conclusions

These findings reinforce the importance of preserving bears’ native habitats and provide new insights, namely on the use of humanized landscapes.

Context

Human demand for natural resources continues to increase owing to climate change and population growth. The supply capacity of ecosystem services has also declined drastically, posing a severe threat to the long-term sustainability of human society.

Objectives

Taking the fast-urbanized Pearl River Delta (PRD) as the study area, the specific research objectives of this study were to intuitively reveal the spatial distribution of ecosystem service supply–demand relationships in rapid urbanization and explore the dominant influencing factors and their impact process on ecosystem service supply–demand relationships.

Methods

It zoned the ecological space based on the ecosystem service supply–demand ratio (ESSDR) evaluated by six typical ecosystem services. And then, the Geographical Detector model, Structural Equation Modeling and regression analysis were used to explore the ranking and threshold effects of influencing factors of ESSDR.

Results

(1) From 2000 to 2020, the ESSDR in the central PRD deteriorated, whereas the ESSDR in the remote areas of the PRD was further optimized. Stable grading eigenvalues of the ESSDR were found based on cumulative frequency curves from 2000 to 2020. (2) Green density (GD) and land development size (LDS) were the dominant natural and social factors influencing ESSDR in the PRD, respectively. (3) There were two thresholds in the impact process of GD (21% and 66%) and LDS (8% and 54%) on the ESSDR, which matched the gradients of urban, developing urban, and rural areas.

Conclusions

There are certain thresholds in the ESSDR responding to land use change. The focus should be on the imbalance in areas with GD < 21% or LDS > 54% and protective measures should be strengthened in areas with GD > 66% or LDS < 8%.

Context

Abiotic filtering, including environmental and dispersal filtering, is frequently observed resulting in reduced diversity and more similar species assemblages following habitat fragmentation. Nonetheless, the significance of competitive exclusion is often underestimated.

Objectives

We investigated the dominant assembly process among termite communities on land-bridge islands, focusing on species known for their high territoriality. We hypothesized that competitively superior species tend to dominate more favorable habitats, such as larger and less isolated islands. Consequently, we anticipated lower diversity and greater similarity in species assemblages than would be expected.

Methods

Termite communities were surveyed using standardized transects on 24 islands. We quantified the standardized effects of island area and isolation on taxonomic, phylogenetic and functional diversity by comparing observed patterns with randomly generated communities (i.e., stochastic process). A phylogenetic generalized linear mixed model (PGLMM) was conducted to examine species-specific responses to environmental factors and competition intensity (i.e., heterospecific abundance).

Results

We found that taxonomic, phylogenetic and functional diversity were lower than expected on larger and less isolated islands, suggesting that competitive exclusion was the dominant mechanism shaping termite communities in TIL. PGLMM showed that two fungus-growing species with larger body sizes increased with competition intensity, while other species exhibited negative responses. Notably, the abundance of fungus-growing species showed sharper increase with island area and decrease with isolation compared to other feeding groups. These findings demonstrate that competitively superior species prefer high-quality habitats and are more sensitive to habitat fragmentation.

Conclusions

Our study highlights the significance of competitive exclusion in shaping termite communities and emphasizes the need to consider both competitive and niche difference among species or functional groups when predict changes in community structure and biodiversity loss resulting from habitat fragmentation.