19 results on '"ecological assessments"'
Search Results
2. Assessing Impacts of Human Stressors on Stream Fish Habitats across the Mississippi River Basin.
- Author
-
Ross, Jared A., Infante, Dana M., Cooper, Arthur R., Whittier, Joanna B., and Daniel, Wesley M.
- Subjects
FRESHWATER fishes ,FISH habitats ,HABITATS ,RIVER conservation ,FISH conservation ,CONSERVATION projects (Natural resources) ,WATERSHEDS - Abstract
Effective conservation of stream fishes and their habitats is complicated by the fact that human stressors alter the way in which natural factors such as stream size, catchment geology, and regional climate influence stream ecosystems. Consequently, efforts to assess the condition of stream fishes and their habitats must not only attempt to characterize the effects of human stressors but must account for the effects of natural influences as well. This study is an assessment of all stream fish habitats in the Mississippi River basin, USA. The basin supports over 400 stream fish species, drains a land area of 3.2 M km
2 , and includes a myriad of human stressors such as intensive agriculture, urbanization, nutrient loading, and habitat fragmentation by dams and road/stream crossings. To effectively characterize types and levels of human stressors specifically impacting the basin's stream fish species, our assessment approach first accounted for the influence of natural landscape conditions on species abundances with multiple steps, including stratifying our analyses by region and stream size and quantitatively modeling the influences of natural factors on stream fishes. We next quantified individual fish species responses to explicit human stressors for different measures of land use, fragmentation, and water quality, including summaries of measures in local vs. catchment extents. Results showed that many species had negative threshold responses to human stressors and that impacts varied by species, by region, and by the spatial extents in which stressors were summarized. Our spatially explicit results indicated the degree of stream reach impairment for specific stressor categories, for individual species, and for entire assemblages, all of which are types of information that can aid decision makers in achieving specific conservation goals in the region. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
3. Using Zeta Diversity in Describing the Health of Soft Sediment Benthic Macroinvertebrates in the Southern California Bight.
- Author
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Simons, Ariel Levi, Aulerich, Noah, Carlson, Harold, Chandra, Inessa, Chancellor, Jordan, Gemayel, Georgina, Gillett, David James, Levene, Dylan, Lin, Jonathon, Nichol, Georgia, Patel, Hetal, and Zhu, Serena
- Subjects
- *
MARINE sediments , *ECOLOGICAL assessment , *INVERTEBRATES , *SEDIMENTS , *COMMUNITIES - Abstract
Simons, A.L.; Aulerich, N.; Carlson, H.; Chandra, I.; Chancellor, J.; Gemayel, G.; Gillett, D.J.; Levene, D.; Line, J.; Nichol, G.; Patel, H., and Zhu, S., 2023. Using zeta diversity in describing the health of soft sediment benthic macroinvertebrates in the Southern California Bight. Journal of Coastal Research, 39(3), 418–430. Charlotte (North Carolina), ISSN 0749-0208. Ecological assessments of marine sediments have often focused on measures derived from the taxonomic, and sometimes functional, diversity of individual assemblages of benthic macroinvertebrates (BMIs). These assemblages are linked by a variety of ecological processes, demonstrating a need to describe groupings of them using regional measures of diversity. Here the use of zeta diversity is demonstrated, as a novel generalization of diversity measures, in assessing the health of regional groupings of BMI assemblages in the sediments of nearshore habitats such as estuaries and embayments. Using 1203 samples of BMI assemblages found in Southern California Bight (SCB), a model was constructed using three orders of zeta diversity, which accounted for up to 86% of regional variation in the mean health of assemblages, as described by the Benthic Response Index. Also investigated was the use of zeta diversity in assessing the relative likelihood of models of community assembly for regional groupings of BMIs, with niche assembly found to be likelier in both nearshore and offshore habitats. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
4. Constructing ecological indices for urban environments using species distribution models.
- Author
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SIMONS, ARIEL LEVI, CALDWELL, STEVIE, FU, MICHELLE, GALLEGOS, JOSE, GATHERU, MICHAEL, RICCARDELLI, LAURA, TRUONG, NHI, and VIERA, VALERIA
- Subjects
SPECIES distribution ,NUMBERS of species ,URBAN biodiversity ,SPECIES diversity ,RANDOM forest algorithms ,FRESHWATER habitats - Abstract
In an increasingly urbanized world, there is a need to study urban areas as their own class of ecosystems as well as assess the impacts of anthropogenic impacts on biodiversity. However, collecting a sufficient number of species observations to estimate patterns of biodiversity in a city can be costly. Here we investigated the use of community science-based data on species occurrences, combined with species distribution models (SDMs), built using MaxEnt and remotely-sensed measures of the environment, to predict the distribution of a number of species across the urban environment of Los Angeles. By selecting species with the most accurate SDMs, and then summarizing these by class, we were able to produce two species richness models (SRMs) to predict biodiversity patterns for species in the class Aves and Magnoliopsida and how they respond to a variety of natural and anthropogenic environmental gradients. We found that species considered native to Los Angeles tend to have significantly more accurate SDMs than their non-native counterparts. For all species considered in this study we found environmental variables describing anthropogenic activities, such as housing density and alterations to land cover, tend to be more influential than natural factors, such as terrain and proximity to freshwater, in shaping SDMs. Using a random forest model we found our SRMs could account for approximately 54% and 62% of the predicted variation in species richness for species in the classes Aves and Magnoliopsida respectively. Using community science-based species occurrences, SRMs can be used to model patterns of urban biodiversity and assess the roles of environmental factors in shaping them. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
5. Spatial distribution of per- and polyfluoroalkyl substances (PFAS) in waters from Central and South Florida.
- Author
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Li, Xuerong, Fatowe, Morgan, Lemos, Leila, and Quinete, Natalia
- Subjects
FLUOROALKYL compounds ,LIQUID chromatography-mass spectrometry ,CANALS ,AQUATIC resources ,PERSISTENT pollutants - Abstract
Per- and polyfluoroalkyl substances (PFAS) are notoriously persistent pollutants that are found ubiquitously present in aquatic environments. They pose a big threat to aquatic life and human health given the bioaccumulation feature and significant adverse health effects associated. In our previous study, PFAS were found in surface waters from Biscayne Bay and tap waters from the East coast of South Florida, at levels that arouse human health and ecological concerns. Considering that Florida supports millions population as well as treasured, sensitive coastal and wetland ecosystems, we have expanded the PFAS monitoring study on the occurrence, composition, spatial distribution, and potential sources encompassing tap waters from counties on the West coast of South Florida and Central Florida, and surface waters from Tampa Bay, Everglades National Park adjacent canals, Key West, including Biscayne Bay area. A total of 30 PFAS were analyzed based on solid-phase extraction (SPE) followed by liquid chromatography tandem mass spectrometry (LC–MS/MS). PFAS were detected in all tap water (N = 10) and surface water samples (N = 38) with total concentrations up to 169 ng L
−1 . Higher PFAS concentrations (> 60 ng L−1 ) are mostly observed from polluted rivers or coastal estuaries in Biscayne Bay, and sites nearby potential points sources (military airbases, wastewater facilities, airports, etc.). Our findings on current PFAS contamination levels from diverse aquatic environments provide additional information for the development of more stringent screening levels that are protective of human health and the environmental resources of Florida, which is ultimately anticipated as scientific understanding of PFAS is rapidly growing. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
6. Assessing Impacts of Human Stressors on Stream Fish Habitats across the Mississippi River Basin
- Author
-
Daniel, Jared A. Ross, Dana M. Infante, Arthur R. Cooper, Joanna B. Whittier, and Wesley M.
- Subjects
streams ,rivers ,habitats ,catchments ,natural influences ,human stressors ,ecological assessments ,water quality ,stream fragmentation ,land use - Abstract
Effective conservation of stream fishes and their habitats is complicated by the fact that human stressors alter the way in which natural factors such as stream size, catchment geology, and regional climate influence stream ecosystems. Consequently, efforts to assess the condition of stream fishes and their habitats must not only attempt to characterize the effects of human stressors but must account for the effects of natural influences as well. This study is an assessment of all stream fish habitats in the Mississippi River basin, USA. The basin supports over 400 stream fish species, drains a land area of 3.2 M km2, and includes a myriad of human stressors such as intensive agriculture, urbanization, nutrient loading, and habitat fragmentation by dams and road/stream crossings. To effectively characterize types and levels of human stressors specifically impacting the basin’s stream fish species, our assessment approach first accounted for the influence of natural landscape conditions on species abundances with multiple steps, including stratifying our analyses by region and stream size and quantitatively modeling the influences of natural factors on stream fishes. We next quantified individual fish species responses to explicit human stressors for different measures of land use, fragmentation, and water quality, including summaries of measures in local vs. catchment extents. Results showed that many species had negative threshold responses to human stressors and that impacts varied by species, by region, and by the spatial extents in which stressors were summarized. Our spatially explicit results indicated the degree of stream reach impairment for specific stressor categories, for individual species, and for entire assemblages, all of which are types of information that can aid decision makers in achieving specific conservation goals in the region.
- Published
- 2023
- Full Text
- View/download PDF
7. Improving the performance of ecological indices by balancing reference site quality and representativeness.
- Author
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Chen, Kai, Olson, John R., Vander Laan, Jacob J., Hill, Ryan A., Wang, Beixin, and Hawkins, Charles P.
- Subjects
- *
ECOLOGICAL assessment , *WATERSHEDS - Abstract
Reference site networks should consist of minimally disturbed sites that collectively characterize the ranges of natural settings within a region. Compromise between reference-quality and representativeness is required. We evaluated how tradeoffs between reference-quality and regional representativeness affected applicability, performance, and interpretation of multi-metric (MMI) and Observed/Expected (O/E) indices developed for streams in eastern China. We emphasized reference-quality by applying the most-stringent objective criteria and expert-judgment to select reference-group1 (G1). We emphasized representativeness by applying the least-stringent criteria to select reference-group2 (G2) sites from different strata based on watershed size. We balanced reference-quality and representativeness in G3 by applying intermediate stringent criteria from each watershed size stratum used previously. Increasing representativeness using G2 improved index applicability to almost more than twice the number of test sites than when reference-quality maximized using G1. Bias in O/E index was almost eliminated only when reference-quality and representativeness balanced using G3. MMIs developed when reference-quality maximized using G1 eliminated all bias and had the highest precision. High-quality reference with limited representativeness affected the metrics selected for inclusion in MMIs and restricted the sites to which both types of indices could be applied. A balanced approach worked best in this instance and similar approaches should be tested in other regions. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
8. River Ecology
- Author
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Wang, Zhao-Yin, Pan, Bao-Zhu, Wang, Lawrence K., Series editor, and Yang, Chih Ted, editor
- Published
- 2014
- Full Text
- View/download PDF
9. Future Research Requirements for Understanding the Effects of Climate Variability on Fisheries for Their Management
- Author
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Schwing, Franklin B., Peterson, William T., Cyr, Ned, Osgood, Kenric E., Noakes, David L. G., editor, Beamish, Richard J., editor, and Rothschild, Brian J., editor
- Published
- 2009
- Full Text
- View/download PDF
10. Indicators for quantitative evaluation of the social services function of urban greenbelt systems: A case study of shenzhen, China.
- Author
-
Hong, Wuyang and Guo, Renzhong
- Subjects
- *
BIOINDICATORS , *GREENBELTS , *SOCIAL services , *ECOSYSTEM services , *GEOGRAPHIC information systems - Abstract
Existing ecological service assessments of urban green space have concentrated on natural environment, while research on the social services function remains underexplored. Taking Shenzhen as an example, this study starts with integrating the function of green space system with human needs. An indicator assessment technique that combines spatialization, rasterization and detailed of land ecological assessment was established with regard to the benefits of landscape aesthetics, function of disaster prevention and mitigation, and accessibility of park greenbelts. The results show that Shenzhen has very high recreational and cultural value, as the areas above medium level account for 66% of the city’s land area, and the recreational and cultural services are worth approximately 40.8million Yuan. Forest parks and comprehensive parks are important places to carry out social service function, particularly the disaster prevention and mitigation function, and the green spaces for disaster prevention and mitigation can be found in most of the disaster-prone areas. The accessibility of service shows a certain level of centrality, since the highest grade is concentrated in the central Bao’an, central Longgang, and the central part of the city. Based on the GIS overlay analysis, this study recognizes the distribution of essential patches, and constructs the structure of essential patches in urban green greenbelt systems by a combination of point, line, and surface elements. It shows the services of the Shenzhen greenbelt system have high potential for social integration, and this study also discusses the policy implication for macro decision-making. The assessment results objectively reflect multiple social services of the green space system in this region and provide a reference for the management, planning and construction of urban ecology in similar cities. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
11. Functional Behavioral Assessments and Behavior Support Plans for Work-Based Learning.
- Author
-
Kittelman, Angus, Wagner Bromley, Katherine, and Mazzotti, Valerie L.
- Abstract
Work experiences are linked to positive post-school outcomes for youth and young adults with disabilities. Unfortunately, students who struggle to manage conflict and challenges in work settings have a difficult time maintaining employment. Though ecological assessments are used to create supported work plans surrounding socially inappropriate behavior, some students may benefit from a more targeted function-based approach to addressing these behaviors in work settings. This article provides information about how functional behavioral assessments and behavior support plans, tools routinely used in schools, can be adapted for use in employment settings. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
12. The comparability of bioassessments: a review of conceptual and methodological issues1.
- Author
-
Cao, Yong and Hawkins, Charles P.
- Subjects
- *
WATER quality biological assessment , *ECOLOGICAL assessment , *DATA quality , *INVERTEBRATES , *STATISTICAL sampling - Abstract
Differences in the raw data used in bioassessments and choices regarding how those data are analyzed and summarized can affect inferences regarding the status of ecological resources and, thus, the degree to which we can trust individual ecological assessments, compare assessments across different programs and regions, or share data when developing or refining new endpoint indices. Progress in addressing these issues has been hindered by lack of consensus regarding what a general definition of comparability should be in the context of bioassessments and what measures of comparability are appropriate for ecological data. In this paper, we review the state of knowledge regarding the comparability of assessments as affected by differences in raw data (composition and relative abundance of taxa), derived measures (biotic metrics and endpoint indices), and assessment levels (condition classes). We specifically address the extent to which the comparability of assessments can be compromised by systematic differences in data, discuss the factors known to affect data comparability, and consider the techniques available to evaluate and improve comparability. Rigorous assessment of data comparability should be a standard aspect of quality assurance when developing and applying biological indices. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
13. The comparability of bioassessments: a review of conceptual and methodological issues1.
- Author
-
Cao, Yong and Hawkins, Charles P.
- Subjects
WATER quality biological assessment ,ECOLOGICAL assessment ,DATA quality ,INVERTEBRATES ,STATISTICAL sampling - Abstract
Differences in the raw data used in bioassessments and choices regarding how those data are analyzed and summarized can affect inferences regarding the status of ecological resources and, thus, the degree to which we can trust individual ecological assessments, compare assessments across different programs and regions, or share data when developing or refining new endpoint indices. Progress in addressing these issues has been hindered by lack of consensus regarding what a general definition of comparability should be in the context of bioassessments and what measures of comparability are appropriate for ecological data. In this paper, we review the state of knowledge regarding the comparability of assessments as affected by differences in raw data (composition and relative abundance of taxa), derived measures (biotic metrics and endpoint indices), and assessment levels (condition classes). We specifically address the extent to which the comparability of assessments can be compromised by systematic differences in data, discuss the factors known to affect data comparability, and consider the techniques available to evaluate and improve comparability. Rigorous assessment of data comparability should be a standard aspect of quality assurance when developing and applying biological indices. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
14. Method of predicting reference condition biota affects the performance and interpretation of ecological indices.
- Author
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HAWKINS, CHARLES P., YONG CAO, and ROPER, BRETT
- Subjects
- *
ECOLOGICAL assessment , *REGRESSION analysis , *NULL models (Ecology) , *ENVIRONMENTAL impact analysis , *MATHEMATICAL statistics , *ECOLOGICAL research , *RESEARCH natural areas , *BIOTIC communities , *APPLIED ecology - Abstract
1. The statistical rigour and interpretability of ecological assessments is strongly affected by how well we predict the biological assemblages expected to occur in the absence of human-caused stress, i.e. the reference condition. In this study, we examined how the specific method used to predict the reference condition affected the performance of two commonly used types of ecological index: RIVPACS-based O/E indices and multimetric indices (MMIs). 2. These two types of index have generally relied on different approaches to predicting the reference condition. For MMIs, some type of regionalisation is typically used to describe the range of metric values among reference sites and hence the expected range at assessed sites. For O/E indices, continuous modelling is used to predict how the biota varies among sites both among and within regions. Because the prediction method differs for these two types of index, it has been impossible to judge if differences in index performance (accuracy, precision, responsiveness and sensitivity) are caused by differences in the way reference condition biota are predicted or by differences in what the indices measure. 3. We used a common data set of 94 reference sites and 255 managed sites and the same potential set of predictor variables to compare the performance of five different MMIs and three O/E indices that were derived from different prediction methods: null models, multiple linear regression (MLR), classification and regression trees, Random Forests (RF) and linear discriminant functions models (LDM). We then calculated values of these indices for samples collected from the managed catchments as well as samples collected from 13 reference sites that were progressively altered in known ways by a simulation programme. 4. Both the type of predictor used and the type of index affected overall index performance. Modelled indices generally had the greatest sensitivity in assessing managed sites as biologically different from reference. Index sensitivity was determined by both an aspect of index precision (10th percentile of reference condition values) and responsiveness. The O/E indices showed the best scope of response to known biological alteration. All three O/E indices decreased linearly in response to simulated alteration in both overall assemblage structure (Bray-Curtis dissimilarity) and taxa loss. The MMIs declined linearly from low to intermediate levels of assemblage alteration but were less responsive between intermediate and high levels of biological alteration. 5. Insights gained from simulations can aid in testing assumptions regarding index response to stress and help ensure that we select indices that are ecologically interpretable and most useful to resource managers. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
15. The factorial validity and internal consistency of the Instrumental Activities of Daily Living Profile in individuals with a traumatic brain injury.
- Author
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Bottari, Carolina, Dassa, Clément, Rainville, Constant, and Dutil, Élisabeth
- Subjects
- *
BRAIN injuries , *PATIENTS , *DIAGNOSIS , *REHABILITATION centers , *MATHEMATICAL models of psychology , *ACTIVITIES of daily living - Abstract
The objective of the study was to investigate the factorial validity and internal consistency of the Instrumental Activities of Daily Living (IADL) Profile. A group of 96 patients aged 16 to 65 years, with moderate to severe traumatic brain injuries, was recruited from 12 rehabilitation hospitals in Quebec. The IADL Profile was administered by an occupational therapist in each subject's home and community environment. Principal axis factoring and confirmatory factor analysis provide preliminary support for six correlated factors (F): (F1) going to grocery store/shopping for groceries, (F2) having a meal with guests/cleaning up, (F3) putting on outdoor clothing, (F4) obtaining information, (F5) making a budget, (F6) preparing a hot meal for guests. Total explained variance was 73.6%. Cronbach's alpha analysis revealed high to very high internal consistency for all scales ranging from .81 to .98; internal consistency of the total scale was very high (0.95). The findings suggest that the IADL Profile is a promising means of documenting both IADL independence and the repercussions of executive function deficits on everyday tasks in real-world environments. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
16. A flexible and practical framework for reporting on ecologically sustainable development for wild capture fisheries
- Author
-
Fletcher, W.J., Chesson, J., Sainsbury, K.J., Hundloe, T.J., and Fisher, M.
- Subjects
- *
SUSTAINABLE development , *RISK assessment , *ECOSYSTEM management , *FISHERY management - Abstract
Abstract: The principles of sustainable development (or ecologically sustainable development as it is known in Australia) are now accepted as the foundation for natural resource management worldwide and there are increasing community expectations that they will be implemented explicitly. Previous attempts to assess sustainable development for fisheries have mostly failed because the methods have been too restrictive, often attempting to develop a single set of indicators. In 2000, all the fishery agencies and major stakeholder groups in Australia supported the development of a National ESD Framework. This initiative resulted in a practical system being generated through the results of a series of case studies and stakeholder workshops. The Australian National ESD Framework divides ESD into eight major components within the three main categories of ecological well-being, human well-being and ability to contribute: Four main steps are used to complete an ESD report for a fishery: (1) identify relevant issues, (2) prioritise these using risk assessment, (3) complete appropriately detailed reports on each issue and (4) compile the material into a report. The tools to assist this process are now available and have been used to generate reports for many Australian fisheries. [Copyright &y& Elsevier]
- Published
- 2005
- Full Text
- View/download PDF
17. Use of Road Maps in National Assessments of Forest Fragmentation in the United States
- Author
-
Kurt Riitters, James Wickham, and John Coulston
- Subjects
United States ,ecological assessments ,land-cover maps ,landscape patterns ,road maps ,forest fragmentation ,Biology (General) ,QH301-705.5 ,Ecology ,QH540-549.5 - Abstract
The question of incorporating road maps into U.S. national assessments of forest fragmentation has been a contentious issue, but there has not been a comparative national analysis to inform the debate. Using data and indices from previous national assessments, we compared fragmentation as calculated from high-resolution land-cover maps alone (Method 1) and after superimposing detailed road maps (Method 2). There was more overall fragmentation with Method 2. However, because roads were often adjacent to other nonforest land cover, Method 1 typically detected > 80% of the forest edge and > 88% of the fragmentation of core, i.e., intact, forest that was detected by Method 2. Indices based on individual patch size changed much more for Method 2; for example, area-weighted average patch size was typically 50-90% smaller. The relative geographic distribution of core forest was the same for both methods. Our results emphasize that the question of incorporating road maps must consider the purpose of the assessment, the characteristics of the data, and the relative sensitivities of indices to different patterns of fragmentation. As a practical matter, unless road-caused fragmentation is of special interest, land-cover maps alone may provide an adequate representation of the geography of forest fragmentation.
- Published
- 2004
- Full Text
- View/download PDF
18. Services écosystémiques rendus par la végétation urbaine : application d'approches d'évaluation à la ville de Strasbourg
- Author
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Selmi, Wissal, STAR, ABES, Laboratoire Image, Ville, Environnement [Strasbourg] (LIVE), Université de Strasbourg (UNISTRA), Université de Strasbourg, Christiane Weber, Selmi, Wissal, Institut de la Recherche et de l’Enseignement Supérieur Agricoles de la Tunisie, and Communauté Urbaine de Strasbourg
- Subjects
Monitoring protocol ,I-Tree Eco model ,Modèle i-Tree-Eco ,[SHS.GEO] Humanities and Social Sciences/Geography ,Protocole de suivi ,Fonctions ,Ecological assessments ,[SHS.GEO]Humanities and Social Sciences/Geography ,[SDE.BE] Environmental Sciences/Biodiversity and Ecology ,Evaluation écologique ,[SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems ,[SHS.ENVIR] Humanities and Social Sciences/Environmental studies ,[SHS.ENVIR]Humanities and Social Sciences/Environmental studies ,évaluation écologique ,Functions ,[SDV.EE.ECO] Life Sciences [q-bio]/Ecology, environment/Ecosystems ,Ecosystem services ,modèle i-Tree Eco ,[SDE.BE]Environmental Sciences/Biodiversity and Ecology ,Services écosystémiques ,Espaces végétalisés urbains ,ecological assessment ,Urban green spaces - Abstract
This research work provides two assessment tools based on both ecocentric and anthropogenic approaches. We argued that these approaches are complementary and they lead not only to understand ecological functions of urban green spaces but also to quantify ecosystem services provided to society. Based on bottom up approach, two urban habitats were assessed : lawns and urban forest. Due to the lack of knowledge about ecological functions of urban lawns, it was required to implement a monitoring protocol that helps to provide a baseline and measure the changes of flora composition and structure across urban green spaces. Although monitoring protocol had some limitations, it intended to highlight the response of lawn flora to environmental patterns and to particular human activities such as management techniques and trampling. Urban forest was assessed by quantifying it structure and some ecosystem services and desservices using i-Tree model Eco. Based on biophysical indicators, the model quantify the total carbon stored and the annually carbon sequestered, the annually amount of pollution removal, and the annually amount of biogenic emissions by trees. Although some uncertainty remains about the application of this model, it was shown that urban trees improve local air quality. However, to alleviate air pollution within urban area, planting and managing trees should be associated with an integrative planning strategy that takes into account other factors. Our study also incorporates operational items, so we have tried to provide some guidance to planners and green spaces managers with reference to our assessment results., Le défi de ce travail réside dans l’application conjointe de deux approches d’évaluation de la double-valeur des espaces végétalisés urbains (EVU) en s’inscrivant dans une dimension dualiste «éco-anthropocentrique». Cette posture a permis d’appréhender le fonctionnement de ces espaces et d’en quantifier les services et des services écosystémiques rendus à la société humaine. Ces deux approches se sont basées sur une démarche ascendante fondée sur la caractérisation de deux types de végétation : les pelouses et les arbres urbains. Le manque de connaissance sur le fonctionnement des pelouses urbaines a imposé la mise en place d’un protocole de suivi permettant d’établir un état des lieux initial sur les communautés prairiales qui s’y installent et sur leur dynamique. Bien qu’il n’ait révélé qu’une partie du fonctionnement de la flore prairiale, le protocole de suivi a eu le mérite d’en déterminer sa composition et sa structuration en précisant l’impact de plusieurs facteurs environnementaux et anthropiques. Quant à la végétation arborée, elle a été étudiée en quantifiant les services et des services écosystémiques en appliquant le modèle i-Tree Eco. Fondé sur des indicateurs biophysiques le modèle a fourni des informations sur le taux de stockage et de séquestration du carbone, le taux d’élimination des polluants atmosphériques et le taux d’émissions biogéniques par les arbres urbains. Bien que le recours au modèle soit empreint d’incertitude, il a permis de démontrer le rôle des arbres dans l’amélioration de la qualité de l’air. Mais, pour parvenir à rendre efficacement ce service, la plantation et la gestion des arbres peuvent être intégrées dans une réflexion de planification plus globale. L’objectif opérationnel d’une telle thèse ne se conçoit que par l’apport de connaissances concrètes à disposition des acteurs de terrain. Nous avons donc tenté de fournir quelques indications à ce propos, alliant ainsi recherche et dissémination des connaissances acquises.
- Published
- 2014
19. Use of Road Maps in National Assessments of Forest Fragmentation in the United States
- Author
-
Kurt H. Riitters, John W. Coulston, and James D. Wickham
- Subjects
forests ,forest fragmentation ,roads ,Ecology ,QH301-705.5 ,Fragmentation (computing) ,road maps ,Forestry ,Forest fragmentation ,Land cover ,landscape patterns ,United States ,Geographic distribution ,Geography ,fragmentation ,land-cover maps ,Biology (General) ,Cartography ,ecological assessments ,QH540-549.5 - Abstract
"The question of incorporating road maps into U.S. national assessments of forest fragmentation has been a contentious issue, but there has not been a comparative national analysis to inform the debate. Using data and indices from previous national assessments, we compared fragmentation as calculated from high-resolution land-cover maps alone (Method 1) and after superimposing detailed road maps (Method 2). There was more overall fragmentation with Method 2. However, because roads were often adjacent to other nonforest land cover, Method 1 typically detected > 80% of the forest edge and > 88% of the fragmentation of core, i.e., intact, forest that was detected by Method 2. Indices based on individual patch size changed much more for Method 2; for example, area-weighted average patch size was typically 50-90% smaller. The relative geographic distribution of core forest was the same for both methods. Our results emphasize that the question of incorporating road maps must consider the purpose of the assessment, the characteristics of the data, and the relative sensitivities of indices to different patterns of fragmentation. As a practical matter, unless road-caused fragmentation is of special interest, land-cover maps alone may provide an adequate representation of the geography of forest fragmentation."
- Published
- 2004
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