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1.
Urban forests provide opportunities for outdoor recreation to many people. Knowledge of the motives for visiting forests is needed for the planning and management of these forests. Since forests are used for a diverse set of recreational activities, however, the motives for different activities are multifaceted. To explore recreational motives, this scene preference study conducted in Sweden examined relations between setting evaluations (i.e., mystery, legibility, valence, and activation), setting preference, general forest perceptions, and intention to engage in forest activities. Two alternative models were examined in relation to five different activities: walking, going on outings, exercising, picking berries or mushrooms, and studying plants and animals. Results revealed that preference mediated between setting evaluations and intention to go on outings, whereas setting evaluations were direct predictors of intention to walk and exercise. However, the models did not describe antecedents of intention to pick berries or mushrooms, or to study plants and animals, satisfactorily. In addition, general forest perceptions, particularly emphasising the restorative qualities of forests, were important for intention to engage in all the examined recreation activities. Results are discussed in relation to landscape preference research and attitude-behaviour theory. In addition, practical implications for encouraging forest recreation are highlighted.  相似文献   

2.
Summary

Mature green mango fruit (Mangifera indica L. ‘Kensington Pride’) were stored at 0, 5, 10, 15 or 20°C for 1, 3, 7, 14, 21 or 28 d to induce different levels of chilling injury (CI) and to elucidate its relationship with aroma volatile production. The fruit were removed from storage and allowed to ripen at 22 ± 1°C and CI index was assessed on fully ripe fruit. Aroma volatile compounds were estimated from the pulp of fully ripe fruit. CI index significantly increased as the storage temperature was lowered and the storage period was extended, particularly in the fruit stored at 0, 5 or 10°C. CI symptoms did not develop on fruit stored at 15 or 20°C. Fifty-six aroma volatile compounds were identified from mango fruit pulp using headspace solid phase microextraction (SPME) technique with gas chromatography (GC-FID) and GC combined with mass spectrometry (GC-MS). Among the 56 aroma volatile compounds, 25 were quantified using GC, which included monoterpenes (±-pinene, ²-pinene, myrcene, 2-carene, ±-phellandrene, 3-carene, ±-terpinene, limonene, ocimine, ³-terpinene, ±-terpinolene, and a-terpineol), sesquiterpenes (±-copaene, ±-gurjunene, trans-carophyllene, aromadendrane, ±-humulene, alloaromadendrane, ³-gurjunene, and ledene), hydrocarbon (p-cymene), esters (methyl octanoate and ethyl caprylate), aldehyde (decanal), and norisoprenoid (²-ionone). A significant reduction in total aroma volatiles, monoterpenes, sesquiterpenes, hydrocarbon, esters, aldehyde, and norisoprenoid production were observed in fruit stored at 0, 5, 10 or 15°C compared with fruit stored at 20°C. The degree of reduction in aroma volatile compounds depended on the severity of CI, induced with different storage temperatures and storage periods. In conclusion lower temperature storage induced CI in mango fruit and adversely affected the aroma volatiles production.  相似文献   

3.
Urban woodland vegetation provides people with many aesthetic, ecological and psychological benefits, but can also generate problems concerning people's perception of safety. This paper reviews existing knowledge about perceived personal safety in relation to vegetation, particularly woodland vegetation, in urban green spaces such as parks and residential areas. Individual and social factors, but also vegetation character, maintenance and design, proved to be important for perceived personal safety. Vegetation-related aspects identified as being of particular importance include landscape design, possibilities for overview and control, vegetation density, and vegetation character and maintenance. Vegetation of an open character with low density undergrowth might have positive effects on perceived personal safety without reducing other benefits. Issues for future research include context-based studies to consider several aspects of vegetation and their interactions.  相似文献   

4.
Nature’s contributions to people (NCP) include the regulating, material, and non-material benefits of urban vegetation that improve well-being. It is increasingly important to plan cities that provide multiple types of NCP equitably to all residents of the city. However, due to historical legacies and planning policies, it is common for the most socially and economically vulnerable urban residents to suffer reduced access to the benefits of urban ecosystems. Previous studies of urban NCP have drawn attention to inequity in one or several types of NCP, but few have analysed a broad range. Here we analysed inequity in nine diverse forms of urban NCP across an index of economic and social vulnerability designed specifically to characterise vulnerability to environmental pressures. Furthermore, we used spatial analysis to map co-variance in vulnerability and a composite indicator of urban NCP, thus highlighting priority regions for future investments in green infrastructure. We applied this approach to the city of Christchurch/ Ōtautahi in Aotearoa/ New Zealand, which provides a valuable case study due to its multicultural population and recent history of widespread damage and regeneration following the 2011 earthquake. Overall, the distribution of urban NCP is inequitable to the disadvantage of more vulnerable residents. Residents of more vulnerable neighbourhoods experienced reduced provision of carbon stock, runoff retention, air quality enhancement, shade, educational green space, public outdoor space accessibility, private green space, and bird biodiversity contributions. Conversely, more vulnerable neighbourhoods had greater provision of erosion mitigation (although negligible in magnitude). The wide range of indicators used and assessed in response to vulnerability, coupled with an assessment of the type of vegetation cover (i.e. grass, tall trees) provides greater insights into how inequities in urban NCP can be addressed in future redevelopment.  相似文献   

5.
The present study assesses the spatial distribution of selected land cover classes at two years (1975 and 2000) in a Mediterranean urban area (Athens, Greece) to test the hypothesis that land cover changes determine an increase in the sensitivity of landscape to forest fires on a regional scale. While urban and agricultural areas increased, although with different rates of growth, forests and semi-natural areas decreased in the study area. These changes are reflected in a significant increase of vegetation sensitivity to forest fires measured by the forest fire risk (FR) index developed in the framework of MEDALUS project. The cover classes which contributed the most to the increase of the FR index were crop mosaic, mixed agricultural-natural areas and discontinuous, low-density settlements. Results of the present study indicate that the transformation of the fringe landscape towards low-quality agricultural and pasture areas and fragmented forest patches is potentially detrimental for environmental quality and the ecological fragility of land.  相似文献   

6.
The metacommunity concept provides a spatial perspective on community dynamics, and the landscape provides the physical template for a metacommunity. Several aspects of landscape heterogeneity, such as landscape diversity and composition, and characteristics of the matrix between habitat patches such as habitat connectivity, and geometry of habitat patches, may moderate metacommunity processes. These aspects of landscape heterogeneity are rarely considered explicitly in the metacommunity discussion, however. We propose landscape contrast (i.e., the average dissimilarity in habitat quality between neighboring patches) as a key dimension of landscape heterogeneity. The concept of landscape contrast unifies discrete and continuous landscape representations (homogeneous, gradient, mosaic and binary) and offers a means to integrate landscape heterogeneity in the metacommunity concept. Landscape contrast as perceived by the organisms affects several fundamental metacommunity processes and may thus constrain which metacommunity models may be observed. In a review of empirical metacommunity studies (n = 123), only 22 % of studies were explicit about their underlying landscape model assumptions, with striking differences among taxonomic groups. The assumed landscape model constrained, but did not determine, metacommunity models. Integration and explicit investigation of landscape contrast effects in metacommunity studies are likely to advance ecological theory and facilitate its application to real-world conservation problems.  相似文献   

7.
Summary

Summer bud-grafting (budding) of the red-leaved scion ‘Crimson King’ onto Acer platanoides rootstocks is unreliable. Typically, the rootstock produces copious callus from the incision in the stem, but the scion bud-chip fails to survive and complete the union. Percentage bud-take was consistently low when rootstocks were grown and budded in 2 litre containers (e.g. 33%), moderately high, but below commercially acceptable levels, when grown in a light sandy loam soil in the field (e.g. 77%), and often very high when grown in deep sand beds (e.g. 100%). The growth of larger structural roots was in the order pot < field soil < sand beds, and confining the roots of field-grown rootstocks in porous mesh bags reduced bud-take from 79 to 13% averaged over three sites. Increasing shoot growth by growing rootstocks in a polythene house did not improve bud-take, but increasing the pot size from 2.0 to 7.5 litres did so. Extensive root growth appears to be one of a number of factors determining bud-take, which was increased further by treating the scionwood and rootstocks with a mixture of Benlate and Rovral fungicides prior to budding. These results are discussed in terms of the need to maintain the bud-chip in a viable condition during the union forming process.  相似文献   

8.
Even though Brazil is a mega-diverse country, many Brazilian cities prioritize exotic plants in their treescapes. Aiming to evaluate how much the treescape in Fortaleza (the fifth largest city in Brazil) is aligned with the policy of valorization of native biodiversity, we sampled street and backyard trees surrounding one of the few vegetation fragments of the city, which is an area considered a priority for conservation. We used the vegetation fragment's flora as reference to compare the potential number of local native species with the actual number of native species in the treescape of the site. To account how much of the native flora was present in the surrounding treescape, we made an inventory of the trees in streets, squares and backyards around the vegetation and compared with the native flora of the vegetation fragment. We then compared the ratio of native to exotic species and checked how many native species of the fragment were also in the surrounding treescape. Exotics were prevalent in both number of species and number of individuals, comprising 70% of the species and 86% of the individuals of public spaces, and 79% of the species and 78% of the individuals of private spaces. Only 14% of the native species of the vegetation were also represented in the treescape, and, in general, they comprehended only a few individuals. We argue that the city's treescape should be re-evaluated in order to value native plants more. Native plants in the treescape could be used as an environmental education tool to publicize native biodiversity to citizens.  相似文献   

9.
There have been many studies associating various aspects of greenspaces with physical health. Very few of these investigations are available for developing countries such as Indonesia. Our study focused on evaluating the association between greenspace and the incidence rate of non-communicable diseases (NCDs) in terms of ischemic heart disease (IHD), diabetes mellitus (DM), rheumatoid arthritis (RA), and chronic kidney disease (CKD). Greenspace was presented by satellite-derived normalized difference vegetation index (NDVI) and forest-related green cover datasets to define exposures to the resolution of 250-m. The Institute for Health Metrics and Evaluation provided age and gender incident data of NCDs at the province level. A generalized additive mixed model coupled with sensitivity test was used to evaluate the exposure-outcome association. Stratified analyses were also employed. After adjusting for covariates, there was a significant negative association for incidence of NCDs and greenspace. We found that an interquartile unit increase of NDVI, and a percentage of forest were closely related to a decrease in the risk of NCDs by 0.3–9.4% and 0.6–6.2%, respectively. Stratified by exposure level, a greater effect of greenspace on reducing NCDs risk occurred in high exposure areas. Considering the socioeconomic factors, greenspace could influence on reducing NCD risks in high urbanization, low-high poverty, and low-high literacy areas. An increment unit of greenspace was associated with a decreased risk of NCDs. This study underscores important health benefits associated with exposures to nature supporting efforts to preserve greenspaces in Indonesia.  相似文献   

10.
A large research program in the Australian monsoon tropics has concluded that monsoon rainforests have expanded within the savanna matrix, a trend that has been emulated throughout the tropics worldwide. The driver of the northern Australian trend was not resolved, but it was suggested to be linked to a long-term trend towards wetter climates, atmospheric CO2 enrichment, and changed fire regimes. We review these findings with particular consideration of its analytical and evidentiary basis and plausibility of the global change hypothesis. Field validation has largely demonstrated that the aerial photographic technique that underpinned the previous research is reliable enough to detect rainforest expansion. Statistical modelling demonstrated that the expansion is related to sites with regionally low fire activity, although models are of low explanatory power reflecting the sketchy historical records of fire and feral animal impacts. Field studies show that current fire regimes adjacent to expanding rainforest patches are causing populations of the native conifer Callitris intratropica, an obligate seeder, to crash. Therefore, it is unlikely that changes in fire regimes, which have been deleterious to other fire-sensitive taxa and plant communities in the region, are responsible for the rainforest expansion. We conclude that the expansion of monsoon rainforests is most plausibly linked to the current wetting trend or elevated CO2 concentration. Increases in either water availability or CO2 concentration can potentially overwhelm the negative feedback between fire and rainforest cover that is responsible for the meta-stability of monsoon rainforest boundaries. However, further research at the continental scale, using aerial photography, tree rings and other proxies, is required to evaluate this hypothesis.  相似文献   

11.
Landscape sustainability can be considered in terms of order and disorder, where order implies causality, well-defined boundaries and predictable outcomes, while disorder implies uncertain causality, shifting boundaries and often-unpredictable outcomes. We address the interplay of order and disorder in social–ecological landscapes (SELs) using spatiotemporal analysis of entropy-related indices of Normalized Difference Vegetation Index time-series. These indices can provide insights for complex systems analysis for the evaluation of adaptive capacity in SELs. In particular, our overarching aim is to help interpret what an increase of order/disorder means with regards to SELs and the underlying drivers and causes of conditions in SELs. The approach can be used to increase spatially explicit anticipatory capability in environmental science and natural resource management based on how the system has responded to stress in the past. Such capability is crucial to address SEL adaptive capacity and for sustainable planning given that surprises may increase as a consequence of both climate change and multiple interacting anthropogenic stressors. These advancements should greatly contribute to the application of spatial resilience strategies in general, and to sustainable landscape planning in particular, and for the spatially explicit adaptive comanagement of ecosystem services.  相似文献   

12.
13.
Three physiologically distinct forms of the same genotype of Quercus robur ‘Fastigiata’, all derived from adult budwood, were identified following the growth of severely-pruned hedge plants grafted onto juvenile seedling rootstocks. Only explants from the form displaying the juvenile-like characteristic of over-winter leaf retention were capable of establishing sustainable cultures in vitro, although growth was not as rapid as those from a two year old seedling source. Pruning to release correlative inhibition of buds low on the scion framework produced vigorous shoot growth, but explants from these failed to show sustained growth in vitro. Withholding light from stockplants reduced excessive phenolic oxidation in explants taken from flushing unripe shoots, however, despite a beneficial effect on culture initiation, later growth was dependent upon the juvenile- or adult-like physiology of the original explant. A new medium was devised for this subject, which in addition to promoting growth generally, also stimulated the flushing of shoot apices. The relevance to in vitro culture of expression of juvenile habit in the stockplant is discussed.  相似文献   

14.
Improved understandings of the agricultural and range ecologies ofsemi-arid Africa require better information on the spatiotemporal distributionof domestic livestock across agropastoral landscapes. An empirical GIS-basedapproach was developed for estimating distributions of herded livestock acrossthree agropastoral territories (around 100 km2 each)over a two-year period. Algorithms developed from regression analyses of herdtracking data (with R2s 0.67) are used to transform a morecomprehensive but incomplete set of data generated from herders accounts oftheir herds grazing itineraries (400 herds following 6500 itineraries). Theresulting characterization registers 40 000 days of livestock activitiesacross694 land units (averaging 70 ha) over the study period. This studydemonstrates that rural producers knowledge of their daily extractionpracticescan be translated to fine-grained characterizations of extraction densitiesacross mixed landscapes. The spatiotemporal distribution of livestock that isrevealed by this approach diverges strongly from that predicted bycommonly-usedpoint-diffusion estimation procedures. Instead, the distribution reflects localpatterns of land use, topography, vegetation, settlements, and water points.Grazing and nongrazing times spent in land units are not spatially correlatedand the seasonality of grazing pressure is spatially variable. Therefore, theecological impacts of livestock grazing are spatially variable at fine scalesand there is a significant potential for livestock-mediated nutrient transfersacross agropastoral landscapes. The georeferenced data produced by thisapproachnot only will help evaluate the impact and sustainability of differentmanagement practices but also provides a strong empirical base for improvedspatial modeling of herded livestock.This revised version was published online in May 2005 with corrections to the Cover Date.  相似文献   

15.
16.
The desire to improve urban sustainability is motivating many city planners to adopt growth strategies that increase residential density, leading to substantial changes to urban landscapes. What effect this change will have on biodiversity remains unclear, but it is expected that the role of public greenspace in providing wildlife habitat will become critical. We explored the role of urban “pocket parks” as habitat for birds, and how this role changed with increasing residential density in the surrounding neighbourhood. We found that parks in neighbourhoods with high levels of public greenspace (corresponding to less residential land) supported more bird species and individuals overall, and more woodland-dependent species, insectivores and hollow-nesters. Total greenspace area was more important (included in the best ranked models for all bird responses) than the configuration (number, average size and connectivity) of greenspace patches. The majority of species were common suburban birds, indicating that species we assume are tolerant to urban areas will be negatively affected by increasing residential density. Parks form part of an interconnected network of urban open space. For parks to continue to support a diverse native bird community, the network must be viewed, managed, and maintained in its entirety. We suggest three key management actions to improve the bird diversity values of urban greenspaces in compact cities: (1) Increase urban greenspace cover in residential neighbourhoods. (2) Increase vegetation structure in greenspace. (3) Encourage homeowners to plant trees and shrubs.  相似文献   

17.
Urban tree cover is inequitable in many American cities, with low-income and non-white neighborhoods typically having the least coverage. Some municipal and non-profit tree planting programs aim to address this inequity by targeting low-income neighborhoods; however, many programs face lack of participation or resistance from local residents. In this study, we aimed to uncover the economic, social, cultural, and physical barriers that community leaders face in planting trees and fostering engagement in a neighborhood with low tree canopy. In collaboration with an urban greening nonprofit in Philadelphia, Pennsylvania (US), twenty in-depth interviews were conducted with community leaders in a low canopy neighborhood, North Philadelphia. Half of these leaders were already involved with local tree planting programs, while the other half were not. Findings reveal that despite broad appreciation for trees and greenspaces, there are concerns about the risks and costs residents assume over the course of a tree’s life cycle, the threat of neighborhood development and gentrification associated with trees, limited plantable space, and limited time and capacity for community organizations. Additionally, these barriers to participation may be amplified among low-income and communities of color who face the legacies of historical tree disservices and municipal structural disinvestment. Addressing community concerns regarding the long-term care of trees beyond the initial tree planting would likely require further programmatic support. Overall, this research highlights the complexity of addressing inequities in tree canopy and the importance of integrating resident and community leader perspectives about disservices and management costs into tree planting initiatives.  相似文献   

18.
Although wetland condition assessment procedures have been developed, validated, and calibrated in the continental United States, they have not yet been fully developed or field-tested for wetlands in Hawai‘i. In order to address the need for comprehensive assessment methods for Hawaiian coastal wetlands, our research compared three indicators of landscape condition (landscape development intensity, road density, and forest cover) with wetland condition as measured by rapid assessment methods (RAM) and detailed field data collected on soil and water quality. We predicted that wetlands located in the least developed landscapes would have more nutrient rich soils, yet lower nutrient levels in the surface water, and would receive the highest rapid assessment scores. The hypotheses of our study were generally supported. However, while the correlations between landscape variables and δ15N isotopes and CRAM scores were relatively strong, the correlations between the landscape indicators and the other Level II and III field indicators were not very strong. These results suggest that further calibration and refinement of metrics is needed in order to more accurately assess the condition of Hawaiian coastal wetlands. A more detailed land use map, in addition to more comprehensive assessments of wetland water quality and biotic integrity would likely improve the relationships between indicators of landscape condition and wetland condition. Nonetheless, our research demonstrated that landscape analysis at larger scales (1,000 m buffers and watersheds) could provide managers with valuable information on how regional stressors may be affecting wetland water quality (measured as δ15N in plant tissue) as well as overall wetland condition (RAM scores).  相似文献   

19.
Summary

This study investigated the activities of key enzymes in the phenylpropanoid pathway and the accumulation of phenolic products in apple peel in response to infection with Venturia inaequalis [(Cooke) G. Wint.]. We compared healthy apple peel with apple peel showing symptomatic scab lesions, and with peel tissue from 1 – 2 mm around the scab lesions in fruit 1 month before maturity [140 d after full bloom (DAFB)] and at physiological maturity (175 DAFB). Infection with V. inaequalis enhanced the synthesis of some phenolic compounds. Compared to healthy peel, scab lesion tissue had ≤ 3.1-times higher hydroxycinnamic acid content, ≤ 1.3-times higher dihydrochalcone content, and ≤ 3.9-times higher flavan-3-ol content. Scab lesions showed slightly higher phenylalanine ammonia-lyase, chalcone synthase, chalcone isomerase, flavonol synthase, and dihydroflavonol 4-reductase activities. The total amount of phenolics remained relatively stable between the two sampling dates, except for epicatechin and caffeic acid which decreased in amount toward fruit maturity, and levels of catechin which increased in more mature fruit. During fruit maturation, only chalcone synthase and chalcone isomerase activities decreased in all tissues examined. This study showed that the phenylpropanoid pathway in apple fruit peel changed significantly following infection with the apple scab pathogen.  相似文献   

20.
A mathematical model is constructed for quantifying urban trees’ effects on mitigating the intensity of ultraviolet (UV) radiation on the ground within different land use types across a city. The model is based upon local field data, meteorological data and equations designed to predict the reduced UV fraction due to trees at the ground level. Trees in Seoul, Korea (2010), produced average UV protection factors (UPF) for pedestrians in tree shade at solar noon (May to August) of 8.3 for park and cemetery land uses and 3.0 for commercial and transportation land uses. The highest daily UPF was 11.8 in the park and cemetery land uses, which has the highest percent canopy cover. This UV model is being implemented within the i-Tree modeling system to allow cities across the world to estimate tree effects on UV exposure. Understanding the impacts of urban trees on UV exposure can be used in developing landscape design strategies to help protect urban populations from UV exposure and consequent health impacts.  相似文献   

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