Environmental drivers of community diversity in a neotropical urban landscape: a multi-scale analysis

Context

Many aquatic communities are linked by the aerial dispersal of multiple, interacting species and are thus structured by processes occurring in both the aquatic and terrestrial compartments of the ecosystem.

Objectives

To evaluate the environmental factors shaping the aquatic macroinvertebrate communities associated with tank bromeliads in an urban landscape.

Methods

Thirty-two bromeliads were georeferenced to assess the spatial distribution of the aquatic meta-habitat in one city. The relative influence of the aquatic and terrestrial habitats on the structure of macroinvertebrate communities was analyzed at four spatial scales (radius = 10, 30, 50, and 70 m) using redundancy analyses.

Results

We sorted 18,352 aquatic macroinvertebrates into 29 taxa. Water volume and the amount of organic matter explained a significant part of the taxa variance, regardless of spatial scale. The remaining variance was explained by the meta-habitat size (i.e., the water volume for all of the bromeliads within a given surface area), the distance to the nearest building at small scales, and the surface area of buildings plus ground cover at larger scales. At small scales, the meta-habitat size influenced the two most frequent mosquito species in opposite ways, suggesting spatial competition and coexistence. Greater vegetation cover favored the presence of a top predator.

Conclusions

The size of the meta-habitat and urban landscape characteristics influence the structure of aquatic communities in tank bromeliads, including mosquito larval abundance. Modifications to this landscape will affect both the terrestrial and aquatic compartments of the urban ecosystem, offering prospects for mosquito management during urban planning.

     

Deciduous trees increase bat diversity at stand and landscape scales in mosaic pine plantations

Context

In heterogeneous landscapes, habitat complementation is a key process underlying the distribution of mobile species able to exploit non-substitutable resources over large home ranges. For instance, insectivorous bats need to forage in a diversity of habitat patches offering varied compositions and structures within forest landscape mosaics to fulfill their life cycle requirements.

Objectives

We aimed at analyzing the effects of forest structure and composition measured at the stand and landscape scales on bat species richness, abundance and community composition in pine plantation forests of south-western France.

Methods

We sampled bat communities at different periods of the summer season using automatic ultrasound recorders along a tree composition gradient from pine monocultures to pure oak stands. We analyzed bat species activity (as a proxy for bat abundance) and species richness with linear mixed models. Distance-based constrained ordinations were used to partition the spatio-temporal variation in bat communities.

Results

Deciduous tree cover increased bat activity and modified community composition at both stand and landscape scales. Changes in bat communities were mostly driven by landscape-scale variables while bat activity responded more to stand-scale predictors.

Conclusions

The maintenance of deciduous trees at both stand and landscape scales is likely critical for bat communities living in fast-growing conifer plantations, by increasing the availability and diversity of prey and roosting sites. Our study suggests that bats respond to forest composition at both stand and landscape scales in mosaic plantation landscapes, mainly through a resource complementation process.

     

The influence of landscape relative to site and patch variables on primate distributions in the Colombian Llanos

Context

Primates are an important component of biodiversity in tropical regions. However, many studies on the effects of habitat change on primates ignore the relative influence of landscape composition and configuration.

Objectives

This study addresses the question: how important are landscape-scale forest area and composition relative to patch-scale (1–1080 ha) and site-scale (transect of 1 km) habitat variables for the occupancy and abundance of four primate species in the Colombian Llanos.

Methods

Using a randomly stratified survey design, 81 fragments were surveyed for primate occupancy and abundance. We used zero-inflated models to test the relative influence of landscape-scale, patch-scale and site-scale variables on occupancy and abundance for each species. A 95% confidence set of models was constructed using the cumulative Akaike weight for each model and the relative importance of each set of variables calculated for each primate species.

Results

Occupancy was determined by a combination of site-scale, patch-scale and landscape-scale variables but this varied substantially among the primate species.

Conclusion

Our study highlights the importance of managing primates at a range of scales that considers the relative importance of site-, patch- and landscape-scale variables.

     

Walkability in urban landscapes: a comparative study of four large cities in China

Context

Walkability is an important element for assessing the sustainability of urban landscapes. There are increased concerns that as the world becomes more urbanized, cities become less walkable.

Objectives

We aim to develop a composite walkability index to evaluate the spatio-temporal pattern of the walkability of cities. By using the index to evaluate four major cities China, we also aim to provide policy implications.

Methods

A comprehensive walkability index is developed to integrate five aspects of the urban built environment: dwelling density, street connectivity, land-use mix, access to public transit, and flatness. Shanghai, Hangzhou, Chongqing, and Lanzhou are chosen as case studies to evaluate the spatio-temporal patterns and changes of walkability in the context of rapid urban expansion.

Results

Great variations exist among the four cities in terms of speed, scale, and locations of changes of walkability. During 2000–2010, the inner cities of Hangzhou, Chongqing, and Lanzhou and the entire cities of Shanghai and Chongqing increased their walkability index, whereas the inner city of Shanghai had decreased walkability. Furthermore, while inner cities of Shanghai and Hangzhou experienced decreased or stable walkability, the inner cities of Lanzhou and Chongqing enjoyed moderate to high increases in walkability. For inner cities, Shanghai had the highest average walkability index, whereas Lanzhou held the lowest in 2010.

Conclusions

The spatiotemporal changes in walkability seem to be closely associated with governmental policies and planning. The walkability index method can be widely implemented for any urban landscape because of its comprehensiveness, simplicity, and flexibility.

     

Scale-specific land cover thresholds for conservation of stream invertebrate communities in agricultural landscapes

Context

In agricultural landscapes, riparian forests are used as a management tool to protect stream ecosystems from agricultural activities. However, the ability of managers to target stream protection actions is limited by incomplete knowledge of scale-specific effects of agriculture in riparian corridor and catchment areas.

Objectives

We evaluated scale-specific effects of agricultural cover in riparian corridor and catchment areas on stream benthic macroinvertebrate (BMI) communities to develop cover targets for agricultural landscapes.

Methods

Sixty-eight streams assigned to three experimental treatments (Forested Riparian, Agricultural Riparian, Agricultural Catchment) were sampled for BMIs. Ordination and segmented regression were used to assess impacts of agriculture on BMI communities and detect thresholds for BMI community metrics.

Results

BMI communities were not associated with catchment agricultural cover where the riparian corridor was forested, but were associated with variation in catchment agriculture where riparian forests had been converted to agriculture. Trait-based metrics showed threshold responses at greater than 70% agricultural cover in the catchment. Increasing agriculture in the riparian corridor was associated with less diverse and more tolerant BMI communities. Eight metrics exhibited threshold responses ranging from 45 to 75% agriculture in the riparian corridor.

Conclusions

Riparian forest effectively buffered streams from agricultural activity even where catchment agriculture exceeds 80%. We recommend managers prioritize protection of forested riparian corridors and that restore riparian corridors where agricultural cover is near identified thresholds be a secondary priority. Adoption of catchment management actions should be effective where the riparian corridor has been converted to agriculture.

     

Interactive effects of landscape-wide intensity of farming practices and landscape complexity on wild bee diversity

Context

The local intensity of farming practices is considered as an important driver of biodiversity in agricultural landscapes and its effect on biodiversity has been shown to interact with landscape complexity. But the influence of landscape-wide intensity of farming practices on biodiversity and its combined effect with landscape complexity have been little explored.

Objective

In this study, we tested the interactive effect of the landscape-wide intensity of farming practices and landscape complexity on the local species richness and abundance of farmland wild bee communities.

Methods

We captured wild bees in 96 crop fields and explored the effect of landscape-wide intensity of various farming practices along a gradient of landscape complexity (proportion of semi-natural habitats).

Results

We found that species richness and abundance of wild bees were more positively influenced by landscape complexity in highly insecticide-sprayed landscapes than in less intensively managed landscapes. In contrast, we found that the positive effect of landscape complexity on bee species richness only occurred in landscapes with low nitrogen inputs.

Conclusions

Our study demonstrates the interactive effects of landscape-wide farming intensity and landscape complexity in shaping the diversity of farmland wild bee communities. We conclude that the management of farming intensity at the landscape-scale could mitigate the effects of habitat loss on wild bee decline and would help to maintain pollination services in agricultural landscapes.

     

Role of past and present landscape structure in determining epiphyte richness in fragmented Mediterranean forests

Context

The anthropocene is characterised by global landscape modification, and the structure of remnant habitats can explain different patterns of species richness. The most pervasive processes of degradation include habitat loss and fragmentation. However, a recovery of modified landscape is occurring in some areas.

Objectives

The main goal is to know how lichen and bryophyte epiphytic richness growing on Mediterranean forests is influenced not only by fragments characteristics but also by the structure of the landscape. We introduce a temporal dimension in order to evaluate if the historical landscape structure is relevant for current epiphytic communities.

Methods

40 well-preserved forest fragments were selected in a landscape with a large habitat loss over decades, but with a recovery of forest surface in the last 55 years. The most relevant fragment and landscape-scale attributes were considered. Some of the variables were measured in three different years to incorporate a temporal framework.

Results

The results showed that variables at fragment scale had a higher influence, whereas variables at the landscape scale were irrelevant. Among all the historical variables analyzed, only the shift in forest fragment size had influence on species richness.

Conclusions

Mediterranean forests had suffered fragmentation along centuries. Their epiphytic communities also suffer the hard conditions of Mediterranean climate. Our results indicate that Mediterranean epiphytic communities may be in a threshold since it they will never be similar to those communities existing previous fragmentation process even a recovery habitat occur or, they may require more time to response to this habitat recovery.

     

Urban ecology principles: are urban ecology and natural area ecology really different?

Context

To understand, even improve, the land of shrinking nature and spreading urbanization, a science applicable from remote natural areas to cities is needed.

Objective

Today’s scientific principles of urban ecology are articulated and compared with ecology based primarily on natural ecosystems; we either robustly merge the trajectories or watch them diverge.

Methods

A literature review emphasizes that the field of ecology emerged from late 19th century and early 20th century research mostly in semi-natural environments, whereas urban ecology mainly developed from studying plants, habitat types, and ecosystem nutrient flows in late 20th century city environments.

Results

Ninety urban ecology principles are identified and succinctly stated. Underlying the principles, 18 distinctive types of urban attributes are recognized in four major groups: land uses; built objects; permeating anthropogenic flows; human decisions/activities. The attributes or objects studied in “natural area” ecology and urban ecology differ sharply, as do the primary objects present in late 19th century and late 20th century cities. None of the 90 basic principles would have emerged from research on natural areas, and all are readily usable for improving urban and urbanizing areas.

Conclusion

Incorporating urban ecology science into ecology’s body of principles and theory now should catapult the field of ecology to the next level, and noticeably increase its usefulness for society.

     

Species absence in developed landscapes: an experimental evaluation

Context

Conversion of landscapes is widely associated with loss of biodiversity. While there are several competing hypotheses for the local extinction of species in developed landscapes, experimental approaches are seldom applied to elucidating mechanisms.

Objectives

In this study, we focus on the habitat degradation hypothesis and predict that poor quality of relictual wetlands in developed landscapes contributes to the absence of wood frogs (Rana sylvatica = Lithobates sylvaticus) by decreasing their performance.

Methods

In a translocation experiment, we reared wood frog larvae within enclosures in seven ponds where they naturally occur and in five ponds in developed landscapes where they are absent. Premature pond drying precluded assessing performance in one present pond and one absent pond.

Results

Absent ponds were surrounded by upland buffers dominated by developed land covers while ponds with wood frog breeding populations were surrounded primarily by intact forest. Ponds were largely similar in their attributes. Survival and growth rate did not differ between pond types. Development tended to be slightly more rapid in some absent ponds perhaps related to higher water temperatures.

Conclusions

Despite the highly altered landscapes surrounding them, we find no evidence that absent wetlands provide inferior habitat for wood frog larval recruitment. Performance in absent ponds matched or exceeded that observed in present ponds implying that absence of this species may stem from influences mediated by the upland landscape. These results provide a caution to the typically unexamined presumption that relictual habitats in developed landscapes are degraded in their utility for wildlife.

     

The relative impacts of vegetation,topography and spatial arrangement on building loss to wildfires in case studies of California and Colorado

Context

Wildfires destroy thousands of buildings every year in the wildland urban interface. However, fire typically only destroys a fraction of the buildings within a given fire perimeter, suggesting more could be done to mitigate risk if we understood how to configure residential landscapes so that both people and buildings could survive fire.

Objectives

Our goal was to understand the relative importance of vegetation, topography and spatial arrangement of buildings on building loss, within the fire’s landscape context.

Methods

We analyzed two fires: one in San Diego, CA and another in Boulder, CO. We analyzed Google Earth historical imagery to digitize buildings exposed to the fires, a geographic information system to measure some of the explanatory variables, and FRAGSTATS to quantify landscape metrics. Using logistic regression we conducted an exhaustive model search to select the best models.

Results

The type of variables that were important varied across communities. We found complex spatial effects and no single model explained building loss everywhere, but topography and the spatial arrangement of buildings explained most of the variability in building losses. Vegetation connectivity was more important than vegetation type.

Conclusions

Location and spatial arrangement of buildings affect which buildings burn in a wildfire, which is important for urban planning, building siting, landscape design of future development, and to target fire prevention, fuel reduction, and homeowner education efforts in existing communities. Landscape context of buildings and communities is an important aspect of building loss, and if taken into consideration, could help communities adapt to fire.

     

The role of bioclimatic features,landscape configuration and historical land use in the invasion of an Asian tree in subtropical Argentina

Context

Knowing which factors determine the spread of plant invaders is a relevant issue in global ecology. Cultural landscapes both influence and are affected by exotic species. Although bioclimatic boundaries, seed sources and landscape configuration all control the invasion process, they have been mostly studied separately and independently from their distant drivers.

Objectives

We followed a multiscale approach to describe the invasion dynamics of the Asian tree (Ligustrum lucidum) in subtropical NW Argentina cultural landscapes by: (1) identifying the potential bioclimatic area of invasion, (2) mapping the currently invaded area in peri-urban focal sectors, and (3) quantitatively describing the landscape-scale patterns of invasion in relation to environmental and cultural variables.

Method

Niche models were used to map potential invasion area, remote sensing, GIS and field surveys to map patterns of invasion and their association to landscape and environmental variables.

Results

Climate suitability to L. lucidum extends over important ranges of the studied area, but currently invaded areas are mostly restricted to clusters around the main cities. The historical and demographic features of cities (e.g., date foundation, population) are important in predicting invaded forest location and spread. At local scale, invasion is associated to abandoned fields nearby urban centers, roads and rivers.

Conclusions

The invasion patterns of L. lucidum reflect the combined effect of historical socioeconomic connections between Asia and America, as well as the local cultural landscape history and configuration. Teleconnected cultural landscapes need to be explored as a theoretical framework for the study of biological invasions in the Anthropocene.

     

The formulations of site-scale processes affect landscape-scale forest change predictions: a comparison between LANDIS PRO and LANDIS-II forest landscape models

Context

Forest landscape models (FLMs) are important tools for simulating forest changes over broad spatial and temporal scales. The ability of FLMs to accurately predict forest changes may be significantly influenced by the formulations of site-scale processes including seedling establishment, tree growth, competition, and mortality.

Objective

The objectives of this study were to investigate the effects of site-scale processes and interaction effects of site-scale processes and harvest on landscape-scale forest change predictions.

Methods

We compared the differences in species’ distribution (quantified by species’ percent area), total aboveground biomass, and species’ biomass derived from two FLMs: (1) a model that explicitly incorporates stand density and size for each species age cohort (LANDIS PRO), and (2) a model that explicitly tracks biomass for each species age cohort (LANDIS-II with biomass succession extension), which are variants from the LANDIS FLM family with different formulations of site-scale processes.

Results

For early successional species, the differences in simulated distribution and biomass were small (mostly less than 5 %). For mid- to late-successional species, the differences in simulated distribution and biomass were relatively large (10–30 %). The differences in species’ biomass predictions were generally larger than those for species’ distribution predictions. Harvest mediated the differences on landscape-scale predictions.

Conclusions

The effects of site-scale processes on landscape-scale forest change predictions are dependent on species’ ecological traits such as shade tolerance, seed dispersal, and growth rates.

     

Incorporating soil ecosystem services into urban planning: status,challenges and opportunities

Context

Traditionally soils have not received much attention in urban planning. For this, tools are needed that can both be understood both by soil scientists and urban planners.

Purpose

The purpose of this paper is to enhance the role of soil knowledge in urban planning practice, through the following objectives: (1) identifying the role soil plays in recent urban plans; (2) analysing the ecosystem services and indicators used in soil science in an urban context; and (3) inferring the main challenges and opportunities to integrate soil into urban planning.

Methods

Seven urban plans and reports of world cities that include sustainability goals were analysed using text-mining and qualitative analysis, with a critical view on the inclusion of soil-related concepts. Secondly, the contribution of soil science to urban planning was assessed with an overview of case studies in the past decade that focus on soil-related ecosystem services in urban context.

Results

The results show an overall weak attention to soil and soil-related ecosystem services in the implementation and monitoring phases of urban plans. The majority of soil science case studies uses a haphazard approach to measure ecosystem service indicators which may not capture the ecosystem services appropriately and hence lack relevance for urban planning.

Conclusions

Even though the most urban plans assessed recognize soil as a key resource, most of them fail to integrate indicators to measure or monitor soil-related functions. There is a need to develop soil-related ecosystem services that can be easily integrated and understood by other fields.

     

Cityscape quality and resource manipulation affect natural enemy biodiversity in and fidelity to urban agroecosystems

Context

Complex landscapes with high resource availability can support more diverse natural enemy communities and better natural pest control by providing resources and facilitating organism dispersal. Moreover, in agricultural landscapes, local agroecosystem management can support biodiversity maintenance and pest control by adding resources in less complex landscapes with fewer resources. However, we lack an understanding of how local and landscape factors interact to affect natural enemy communities and their site fidelity to agroecosystems in urban landscapes (i.e., cityscapes).

Objective

To better understand how local and landscape factors influence natural enemies in urban agroecosystems, we used urban community gardens as a model system to test if and how local resource manipulation and differences in cityscape quality affect natural enemy (ladybird beetles, parasitoid wasps) communities and their fidelity to urban habitats.

Methods

We performed two manipulations. First, we added local floral resources in 6 of 12 gardens situated in different cityscapes to measure differences in natural enemy biodiversity. Second, in those 12 gardens, with and without resource additions, we manipulated populations of a common natural enemy, Hippodamia convergens, to assess fidelity to the gardens.

Results

Floral resource additions increased parasitoid abundance and changed community composition, but had little effect on ladybeetle abundance, richness or site fidelity. Rather, ladybeetle fidelity to gardens was lower in gardens in low quality cityscapes with high impervious cover.

Conclusions

Cityscape quality influences natural enemies in and fidelity to gardens. Landscape-moderated biodiversity patterns observed in rural landscapes likely differ from urban contexts with implications for pest control.

     

Landscape-scale distribution of tree roosts of the northern long-eared bat in Mammoth Cave National Park,USA

Context

The roosting habits of many temperate zone bats are well documented at microhabitat scales, but fewer studies have included multi-scale assessments of landscape patterns in bat roost site selection.

Objectives

To identify and assess at the landscape-scale the location of spring and early season maternity roosts of female northern long-eared bats (Myotis septentrionalis) from 2015 to 2016 at Mammoth Cave National Park (MACA), Kentucky, USA.

Methods

We used mist-nets and radiotelemetry to catch and track bats to roost trees across the landscape of MACA. Data on roosting sites were evaluated using spatial point pattern analysis to examine distributional trends of roosts. A variety of spatial covariates were used to model the effect of landscape pattern, including: forest type, elevation, and proximity to hibernacula, water, and road corridors.

Results

Data indicate that roost locations of female northern long-eared bats in MACA were typically situated within 2000 m of known winter hibernacula, occurring more often at higher elevations in mesic upland deciduous forests, and in close proximity to water sources and roads. We present hypotheses to account for the patterns observed in relation to landscape features and habitat resources in the Park.

Conclusions

Our data indicate that a more comprehensive understanding of habitat requirements which includes empirically-based, landscape-scale patterns, and not solely considerations at stand or local levels, could lead to better informed management policies targeting conservation of maternity habitat of forest-dwelling bats, including the northern long-eared bat, a species in decline throughout much of its distribution in North America.

     

Temporal and spatial patterns of wetland extent influence variability of surface water connectivity in the Prairie Pothole Region,United States

Context

Quantifying variability in landscape-scale surface water connectivity can help improve our understanding of the multiple effects of wetlands on downstream waterways.

Objectives

We examined how wetland merging and the coalescence of wetlands with streams varied both spatially (among ecoregions) and interannually (from drought to deluge) across parts of the Prairie Pothole Region.

Methods

Wetland extent was derived over a time series (1990–2011) using Landsat imagery. Changes in landscape-scale connectivity, generated by the physical coalescence of wetlands with other surface water features, were quantified by fusing static wetland and stream datasets with Landsat-derived wetland extent maps, and related to multiple wetness indices. The usage of Landsat allows for decadal-scale analysis, but limits the types of surface water connections that can be detected.

Results

Wetland extent correlated positively with the merging of wetlands and wetlands with streams. Wetness conditions, as defined by drought indices and runoff, were positively correlated with wetland extent, but less consistently correlated with measures of surface water connectivity. The degree of wetland–wetland merging was found to depend less on total wetland area or density, and more on climate conditions, as well as the threshold for how wetland/upland was defined. In contrast, the merging of wetlands with streams was positively correlated with stream density, and inversely related to wetland density.

Conclusions

Characterizing the degree of surface water connectivity within the Prairie Pothole Region in North America requires consideration of (1) climate-driven variation in wetness conditions and (2) within-region variation in wetland and stream spatial arrangements.

     

Ecological contributions to human health in cities

Context

Ecological research, from organismal to global scales and spanning terrestrial, hydrologic, and atmospheric domains, can contribute more to reducing health vulnerabilities. At the same, ecological research directed to health vulnerabilities provides a problem-based unifying framework for urban ecologists.

Objective

Provide a framework for expanding ecological research to address human health vulnerabilities in cities.

Methods

I pose an urban ecology of human health framework that considers how the ecological contributions to health risks and benefits are driven by interacting influences of the environment, active management, and historical legacies in the context of ecological self-organization. The ecology of health framework is explored for contrasting examples including heat, vector borne diseases, pollution, and accessible greenspace both individually and in a multifunctional landscape perspective.

Results

Urban ecological processes affect human health vulnerability through contributions to multiple hazard and well-being pathways. The resulting multifunctional landscape of health vulnerability features prominent hotspots and regional injustices. A path forward to increase knowledge of the ecological contributions to health vulnerabilities includes increased participation in in interdisciplinary teams and applications of high resolution environmental sensing and modeling.

Conclusions

Research and management from a systems and landscape perspective of ecological processes is poised to help reduce urban health vulnerability and provide a better understanding of ecological dynamics in the Anthropocene.

     

Does the response of bird assemblages to fire mosaic properties vary among spatial scales and foraging guilds?

Context

An increasing number of studies have investigated the impact of environmental heterogeneity on faunal assemblages when measured at multiple spatial scales. Few studies, however, have considered how the effects of heterogeneity on fauna vary with the spatial scale at which the response variable is characterised.

Objectives

We investigated the relationship between landscape properties in a region characterised by diverse fire mosaics, and the structure and composition of avian assemblages measured at both the site- (1 ha) and landscape-scale (100 ha).

Methods

We surveyed birds and calculated spatial landscape properties in sub-tropical woodlands of central Queensland, Australia.

Results

Environmental heterogeneity, as measured by topographic complexity, was consistently important for bird species richness and composition. However, the explanatory power of topographic complexity varied depending on the spatial scale and the component of diversity under investigation. We found different correlates of richness within particular foraging guilds depending on the scale at which richness was measured. Extent of long-unburnt habitat (>10 years since fire) was the most important variable for the landscape-scale richness of frugivores, insectivores and canopy feeders, whereas environmental heterogeneity in the surrounding landscape was more important for site-scale richness of these foraging guilds.

Conclusions

The response of species richness to landscape characteristics varies among scales, and among components of diversity. Thus, depending on the scale at which a biodiversity conservation goal is conceptualised—maximising richness at a site, or across a landscape—different landscape management approaches may be preferred.

     

How many principles of urban ecology are there?

Context

The nature of urban ecology theory is controversial. Issues include whether urban theory is distinct, whether it has principles, and whether those principles differ from those for non-urban systems. Recently, Richard Forman enumerated urban ecology principles, while we have previously articulated different urban ecology principles. This raises the question of whether there are legitimately different sets of principles.

Objectives

Recognizing the legitimacy of Forman’s principles, we wish to determine whether different methodological assumptions can lead to different sets of urban ecology principles.

Methods

We contrast Forman’s 90 urban ecology principles with our much smaller set to determine why they differ in detail, empirical motivation, and generality. We identify the approaches that generate each set of principles, and seek an inclusive framework to integrate them.

Results

The alternative sets represent contrasting approaches to identifying principles: Forman’s approach is more inductive, generating principles from a body of empirical cases, while our concise roster is more deductive, focusing on general ideas from which the details of specific cases can be derived. Both are legitimate.

Conclusions

Principles of urban ecology can arise from inductive empirical generalization within specified ecological, cultural, and historical contexts, as shown by Forman. However, urban ecology principles can also emerge from a more general, synthetic impulse as we have shown. Neither approach is necessarily better. Both can contribute to a comprehensive theoretical hierarchy that can advance urban ecology.