Habitats have been undergoing significant changes due to environmental processes and human impact... more Habitats have been undergoing significant changes due to environmental processes and human impact that lead into habitat fragmentation and connectivity loss. To improve quality habitats and maintain ecological connectivity, elements that improve the connectivity of habitats need to be identified. To meet this goal, finding optimal pathways locations plays a key role for designing corridors for biodiversity conservation. Conducted in the Castilla y León region of Spain, this paper aims to determine optimal pathways and to enhance the connectivity of protected areas. To this end, three different scenarios were developed including the Natura 2000 network and their surroundings (Natura 2000, Level 0, and Level 1). We used Restoration Planner (RP) available in GuidosToolbox to analyze the network and detect pairwise optimum restoration pathways between the five largest network objects. Our results demonstrate that connector density varies across the region for each scenario. There was al...
A União Europeia (UE), através da sua iniciativa Natura 2000, estabeleceu a classificação e seleç... more A União Europeia (UE), através da sua iniciativa Natura 2000, estabeleceu a classificação e seleção de áreas protegidas na Europa, a fim de assegurar a conservação da biodiversidade. No entanto, não há parâmetros claros e uniformes para permitir que os países membros tomem as melhores decisões de zoneamento para a conservação da biodiversidade. Por esta razão, uma metodologia baseada na avaliação de critérios de importância para a conservação da biodiversidade é apresentada nesta tese. A metodologia introduzida visa estabelecer critérios relevantes que podem ser analisados através do método estatístico de análise multicritério e interpolação de dados com o método geoestatístico de krigagem. O objetivo é verificar a adequação das áreas designadas para a rede Natura 2000 em Castilla y León, Espanha, e desenvolver uma proposta de zoneamento baseada em valores de importância da biodiversidade quando considerando o uso da terra. A metodologia proposta foi realizada com critérios básicos ...
Proceedings of the 4th Geobia 4th International Conference on Geographic Object Based Image Analysis 07 05 2012 09 05 2012 Rio De Janeiro, 2012
Vector-based landcover (LC) maps derived from GEographic Object-Based Image Analysis (GEOBIA) are... more Vector-based landcover (LC) maps derived from GEographic Object-Based Image Analysis (GEOBIA) are increasingly replacing the traditional raster maps from per-pixel classification, but our strategies for assessing their quality are not yet fully developed. We contend that a complete accuracy assessment of a vector LC map must provide answers to the following questions: (1) What is the proportion of area assigned to each LC class that is actually covered by that class? (2) How does the area wrongly assigned to a class get distributed into the other classes? If we were flying at a low altitude over any given polygon, what is the likelihood that we would agree that (3) the LC class best representing the interior of the polygon is the one appearing on the map; (4) the area enclosed by the polygon can be seen as a self-contained unit or patch; (5) there are no regions, either next to the outside of the polygon or on its inside, that would have better be included in the polygon or excluded from it; and (6) the outline of the polygon (excluding parts affected by 5) follows reasonably well the LC transitions we appreciate from air? Questions 1 and 2 can be answered using a confusion matrix, but not the rest. We discuss the conceptual foundations of our integrated object-based approach to accuracy assessment, and demonstrate its implementation for a wall to wall vector LC map of Alberta, Canada.
Spanish open oak woodlands have had multiple land uses such as firewood extraction and grazing th... more Spanish open oak woodlands have had multiple land uses such as firewood extraction and grazing through centuries. Consequently, 20% of the Spanish forest is coppice forest. This particular agrosilvopastoral system is well widespread in the southern and western part of the Iberian Peninsula. As a result of the implementation of Natura 2000 in Spain, many of these habitats have been included in this network listed as "Dehesas" with evergreen Quercus spp. (Sclerophyllous grazed forests -dehesas-). The main goal of Natura 2000 is assuring "favourable conservation status" of natural habitats and species within these areas (Habitats Directive 92/43/ECC). This is the case of the study area, "Dehesa Boyal" (Ávila), which management plan has been carried out in a public forest land. The current situation is a degraded coppice forest, Quercus pyrenaica and Q.ilex, with a shrub encroachment due to previous firewood extraction. Besides, problems such as soil compac...
AII explanations, data, results etc. contained in this book have been made by the authors to the ... more AII explanations, data, results etc. contained in this book have been made by the authors to the best of their knowledge and have been approved with careo However, some errors could not be excluded. For this reason the explanations etc. are given without any obligations or guarantee by the authors, editors and publisher. They cannot take over any responsibility for eventual erroneous contents. Bibliographic information published by the Deutsche Nationalbibliothek The Deutsche Nationalbibliothek lists this publication in the Deutsche Nationalbibliografie. Detailed bibliographic data are available in the Internet at http://dnb.d-nb.de.
Connectivity loss has been identified as one of the greatest threats to biodiversity, at both the... more Connectivity loss has been identified as one of the greatest threats to biodiversity, at both the species and ecosystem levels. This study aims to find possible correlations between structural connectivity and faunal richness and landscape diversity in Spain's largest region, Castilla y León. Based on data provided by the National Biodiversity Inventory and the CORINE Land Cover land-use mapping for 2000 and 2006, species richness was characterized by the number of species occurring in a grid overlaid on the 10 × 10-km-territory. The Shannon Index for land uses was also calculated in each one of the grid cells, providing information on landscape diversity. Structural connectivity was studied using the Morphological Spatial Pattern Analysis, thus providing information on landscape diversity for different edge widths in two different habitat types. Lastly, the analyses showed that there is a slight relationship between structural connectivity and landscape diversity, but not between structural connectivity and faunal richness.
Tourism is an activity that generates important benefits; in the case of Costa Rica, it focuses i... more Tourism is an activity that generates important benefits; in the case of Costa Rica, it focuses its activity on natural areas, using the different ecosystem services (ES) and obtaining economic and social benefits. However, its ecological value can diminish, making it necessary to implement methods to estimate its sustainability. This paper proposes an evaluation of tourism around ES by applying the MIVES method (Value Integrated Model for Sustainability Evaluation), based on the multi-attribute utility theory, which implies that it transforms different variables into a 0 to 1 relationship, where the closer it is to 1, the more sustainable it is. For this purpose, it considered a decision tree, integrating environmental, economic, and social requirements, 6 criteria, and 13 indicators. The method was applied to two sites, Golfito and Jimenez in Costa Rica. It considered the following stages: (i) literature review and expert consultation, (ii) decision tree, (iii) assignment of weigh...
Cantabrian capercaillie (Tetrao urogallus cantabricus) is listed as endangered according to IUCN ... more Cantabrian capercaillie (Tetrao urogallus cantabricus) is listed as endangered according to IUCN criteria. The high degree of fragmentation and anthropogenic disturbances in capercaillie habitat suggests that habitat patterns may be related to decline of capercaillie populations in northern Spain. The objectives of this study are: (1) determining critical territories for the maintenance of capercaillie connectivity; and (2) evaluating the importance of public forests and their appropriate management to maintain the habitat connectivity for this species. This study is focused on northern Spain, where forest areas are critical for the maintenance of capercaillie. We applied connectivity methodologies based on morphological spatial pattern analysis (MSPA) and the probability of connectivity (PC). The results of the MSPA were incorporated into a standard GIS and compared with the spatial distribution of the public forest. Most of the valuable areas for connectivity were inside the public forests. Moreover, these public forests mainly form continuous features. Therefore, forest planning and management, mainly in public forest, should approach this problem including connectivity considerations and, more specifically, identifying the most critical forest sites for the maintenance of capercaillie habitat.
This paper offers the fundamentals of a space-time reconstruction technique from non timeresolved... more This paper offers the fundamentals of a space-time reconstruction technique from non timeresolved, statistically independent data. An algorithm has been developed to identify and track traveling coherent structures in periodic flows. Flow field phase average is reconstructed with a correlation-based method, similar to POD. This method provides a tool for shedding light on flow dynamics and allows for global dynamics study, instead of being limited to mean statistics or point-based techniques. Flow field phase-average is reconstructed with this novel technique. Noteworthy, the involved computational time is relatively small. Phase-locked average data from time-resolved experiments have been used as a comparison basis. This allows for a direct comparison between real and reconstructed flow fields. Good agreement reveals the method suitability for Particle Image Velocimetry (PIV) measurements. The reconstruction technique is then applied to a set of non time-resolved SPIV measurements in an atmospheric burner, under combustion conditions. Finally, the limitation of the technique applicability to any pseudo periodic flow is further discussed on the basis of the relative modes strength of the Proper Orthogonal Decomposition (POD). The discussion offered allows defining a parameter that indicates the suitability of the technique.
Incorporating risk analysis into physical planning is increasingly necessary to anticipate and ta... more Incorporating risk analysis into physical planning is increasingly necessary to anticipate and take appropriate measures to prevent and defend against disasters. This paper extends the concept of carrying capacity by studying two models: an ecosystem-bringing capacity model and a territorial model of construction on rural land. A climate change variable was integrated into both models, and the changes that occurred depending on the emissions scenario and the time horizons were considered for developing the suitability, impact, and risk models. The data obtained in this study give us an idea of the difficulties that may exist in most of the territory for the construction location on rural land. In fact, only 14% of the occupied study area reaches positive values for the carrying capacity of ecosystems; besides, there are no constructions on rural land located on positive values if we include the risks in the planning. Contextually, assigning a value to the comparable carrying capacity, based on a holistic conception of planning and scientific data, can facilitate the decision-making to initiate future studies and work. Moreover, this study enables to anticipate the effects of climate change when drawing up adaptation and mitigation policies, plans, or programs.
This paper presents a methodology to study the connectivity that livestock trails can offer to gu... more This paper presents a methodology to study the connectivity that livestock trails can offer to guarantee the transit of organisms and access to pasturelands. In this regard, a connectivity analysis was carried out in two scenarios: Basic Scenario (Scenario 1: pasture) and Extended Scenario (Scenario 2: pasture + livestock trails) by using the Morphological Spatial Pattern Analysis (MSPA). The result of structural connectivity analysis, MSPA, showed that livestock trails reduce the fragmentation of the optimal terrain (pasturelands) for livestock activity, since the effective corridors are more numerous, and the edge effect is also reduced. Therefore, MSPA analysis allows the classification of any landscape typology at the pixel level and mapping of corridor structures (connecting elements) and other categories of spatial patterns on a continental scale. The results of the study show the importance of carrying out this type of analysis in different times of the year, detecting the ev...
The space-time dynamics and the effect of urban growth on territory transformation were simulated... more The space-time dynamics and the effect of urban growth on territory transformation were simulated with Iber 2D to analyze flooding events in the lower basin of the Sabinal River, Mexico. We classified the main coverages and land uses of the study area. Soil roughness and water infiltration in the soil were evaluated. Both values were used as input data in a simulation model with Iber 2D to analyze and compare the levels of water height and maximum flood level area with different precipitation values in two reference years, 1986 and 2014. Residential use land cover increased considerably while tree, pasture and agricultural use covers decreased. Consequently, in 2014, precipitation of similar magnitude led to higher values of direct runoff, increasing water levels and therefore the risk of overflowing. The water levels and moments of river overflow provided feedback for flood-risk warning systems and tools to monitor basins lacking adequate infrastructure.
In order to consider forest biomass as a real alternative for energy production, it is critical t... more In order to consider forest biomass as a real alternative for energy production, it is critical to obtain accurate estimates of its availability using non-destructive sampling methods. In this study, we estimate the biomass available in a Scots pine-dominated forest (Pinus sylvestris L.) located in Spain. The biomass estimates were obtained using LiDAR data combined with a multispectral camera and allometric equations. The method used to fuse the data was based on back projection, which assures a perfect match between both datasets. The results present estimates for each of the seven different biomass components: above ground, below ground, log, needles, and large, medium and small branches. The accuracy of the models varied between R 2 values of 0.46 and 0.67 with RMSE% ranging from 15.72% to 35.43% with all component estimates below 20%, except for the model estimating biomass of big branches. The models in this study are suitable for the estimation of biomass and demonstrate that computation is possible at a fine scale for the different biomass components. These remote sensing methods are sufficiently accurate to develop biomass resource cartography for multiple energy uses.
The accurate prediction of forest above-ground biomass is nowadays key to implementing climate ch... more The accurate prediction of forest above-ground biomass is nowadays key to implementing climate change mitigation policies, such as reducing emissions from deforestation and forest degradation. In this context, the coefficient of determination (R 2) is widely used as a means of evaluating the proportion of variance in the dependent variable explained by a model. However, the validity of R 2 for comparing observed versus predicted values has been challenged in the presence of bias, for instance in remote sensing predictions of forest biomass. We tested suitable alternatives, e.g. the index of agreement (d) and the maximal information coefficient (MIC). Our results show that d renders systematically higher values than R 2 , and may easily lead to regarding as reliable models which included an unrealistic amount of predictors. Results seemed better for MIC, although MIC favoured local clustering of predictions, whether or not they corresponded to the observations. Moreover, R 2 was more sensitive to the use of cross-validation than d or MIC, and more robust against overfitted models. Therefore, we discourage the use of statistical measures alternative to R 2 for evaluating model predictions versus observed values, at least in the context of assessing the reliability of modelled biomass predictions using remote sensing. For those who consider d to be conceptually superior to R 2 , we suggest using its square d 2 , in order to be more analogous to R 2 and hence facilitate comparison across studies.
The evaluation of accuracy is essential for assuring the reliability of ecological models. Usuall... more The evaluation of accuracy is essential for assuring the reliability of ecological models. Usually, the accuracy of above-ground biomass () predictions obtained from remote sensing is assessed by the mean differences (), the root mean squared differences (), and the coefficient of determination (2) between observed and predicted values. In this article we propose a more thorough analysis of accuracy, including a hypothesis test to evaluate the agreement between observed and predicted values, and an assessment of the degree of overfitting to the sample employed for model training. Using the estimation of forest from LIDAR and spectral sensors as a case study, we compared alternative prediction and variable selection methods using several statistical measures to evaluate their accuracy. We showed that the hypothesis tests provide an objective method to infer the statistical significance of agreement. We also observed that overfitting can be assessed by comparing the inflation in residual sums of squares experienced when carrying out a cross-validation. Our results suggest that this method may be more effective than analysing the deflation in 2. We proved that overfitting needs to be specifically addressed since, in light of , and 2 alone, predictions may apparently seem reliable even in clearly unrealistic circumstances, for instance when including too many predictor variables. Moreover, Theil's partial inequality coefficients, which are employed to resolve the proportions of the total errors due to the unexplained variance, the slope and the bias, may become useful to detect averaging effects common in remote sensing predictions of. We concluded that statistical measures of accuracy, precision and agreement are necessary but insufficient for model evaluation. We therefore advocate for incorporating evaluation measures specifically devoted to testing observed-versuspredicted fit, and to assessing the degree of overfitting.
In the context of predicting forest attributes using a combination of airborne LIDAR and multispe... more In the context of predicting forest attributes using a combination of airborne LIDAR and multispectral (MS) sensors, we suggest the inclusion of normalized difference vegetation index (NDVI) metrics along with the more traditional LIDAR height metrics. Here the data fusion method consists of back-projecting LIDAR returns onto original MS images, avoiding coregistration errors. The prediction method is based on non-parametric imputation (most similar neighbour). Predictor selection and accuracy assessment include hypothesis tests and overfitting prevention methods. Results show improvements when using combinations of LIDAR and MS compared to using either of them alone. The MS sensor has little explanatory capacity for forest variables dependent on tree height, already well determined from LIDAR alone. However, there is potential for variables dependent on tree diameters and their density. The combination of LIDAR and MS sensors can be very beneficial for predicting variables describing forests structural heterogeneity, which are best described from synergies between LIDAR heights and NDVI dispersion. Results demonstrate the potential of NDVI metrics to increase prediction accuracy of forest attributes. Their inclusion in the predictor dataset may, however, in a few cases be detrimental to accuracy, and therefore we recommend to carefully assess the possible advantages of data fusion on a case-by-case basis.
Habitats have been undergoing significant changes due to environmental processes and human impact... more Habitats have been undergoing significant changes due to environmental processes and human impact that lead into habitat fragmentation and connectivity loss. To improve quality habitats and maintain ecological connectivity, elements that improve the connectivity of habitats need to be identified. To meet this goal, finding optimal pathways locations plays a key role for designing corridors for biodiversity conservation. Conducted in the Castilla y León region of Spain, this paper aims to determine optimal pathways and to enhance the connectivity of protected areas. To this end, three different scenarios were developed including the Natura 2000 network and their surroundings (Natura 2000, Level 0, and Level 1). We used Restoration Planner (RP) available in GuidosToolbox to analyze the network and detect pairwise optimum restoration pathways between the five largest network objects. Our results demonstrate that connector density varies across the region for each scenario. There was al...
A União Europeia (UE), através da sua iniciativa Natura 2000, estabeleceu a classificação e seleç... more A União Europeia (UE), através da sua iniciativa Natura 2000, estabeleceu a classificação e seleção de áreas protegidas na Europa, a fim de assegurar a conservação da biodiversidade. No entanto, não há parâmetros claros e uniformes para permitir que os países membros tomem as melhores decisões de zoneamento para a conservação da biodiversidade. Por esta razão, uma metodologia baseada na avaliação de critérios de importância para a conservação da biodiversidade é apresentada nesta tese. A metodologia introduzida visa estabelecer critérios relevantes que podem ser analisados através do método estatístico de análise multicritério e interpolação de dados com o método geoestatístico de krigagem. O objetivo é verificar a adequação das áreas designadas para a rede Natura 2000 em Castilla y León, Espanha, e desenvolver uma proposta de zoneamento baseada em valores de importância da biodiversidade quando considerando o uso da terra. A metodologia proposta foi realizada com critérios básicos ...
Proceedings of the 4th Geobia 4th International Conference on Geographic Object Based Image Analysis 07 05 2012 09 05 2012 Rio De Janeiro, 2012
Vector-based landcover (LC) maps derived from GEographic Object-Based Image Analysis (GEOBIA) are... more Vector-based landcover (LC) maps derived from GEographic Object-Based Image Analysis (GEOBIA) are increasingly replacing the traditional raster maps from per-pixel classification, but our strategies for assessing their quality are not yet fully developed. We contend that a complete accuracy assessment of a vector LC map must provide answers to the following questions: (1) What is the proportion of area assigned to each LC class that is actually covered by that class? (2) How does the area wrongly assigned to a class get distributed into the other classes? If we were flying at a low altitude over any given polygon, what is the likelihood that we would agree that (3) the LC class best representing the interior of the polygon is the one appearing on the map; (4) the area enclosed by the polygon can be seen as a self-contained unit or patch; (5) there are no regions, either next to the outside of the polygon or on its inside, that would have better be included in the polygon or excluded from it; and (6) the outline of the polygon (excluding parts affected by 5) follows reasonably well the LC transitions we appreciate from air? Questions 1 and 2 can be answered using a confusion matrix, but not the rest. We discuss the conceptual foundations of our integrated object-based approach to accuracy assessment, and demonstrate its implementation for a wall to wall vector LC map of Alberta, Canada.
Spanish open oak woodlands have had multiple land uses such as firewood extraction and grazing th... more Spanish open oak woodlands have had multiple land uses such as firewood extraction and grazing through centuries. Consequently, 20% of the Spanish forest is coppice forest. This particular agrosilvopastoral system is well widespread in the southern and western part of the Iberian Peninsula. As a result of the implementation of Natura 2000 in Spain, many of these habitats have been included in this network listed as "Dehesas" with evergreen Quercus spp. (Sclerophyllous grazed forests -dehesas-). The main goal of Natura 2000 is assuring "favourable conservation status" of natural habitats and species within these areas (Habitats Directive 92/43/ECC). This is the case of the study area, "Dehesa Boyal" (Ávila), which management plan has been carried out in a public forest land. The current situation is a degraded coppice forest, Quercus pyrenaica and Q.ilex, with a shrub encroachment due to previous firewood extraction. Besides, problems such as soil compac...
AII explanations, data, results etc. contained in this book have been made by the authors to the ... more AII explanations, data, results etc. contained in this book have been made by the authors to the best of their knowledge and have been approved with careo However, some errors could not be excluded. For this reason the explanations etc. are given without any obligations or guarantee by the authors, editors and publisher. They cannot take over any responsibility for eventual erroneous contents. Bibliographic information published by the Deutsche Nationalbibliothek The Deutsche Nationalbibliothek lists this publication in the Deutsche Nationalbibliografie. Detailed bibliographic data are available in the Internet at http://dnb.d-nb.de.
Connectivity loss has been identified as one of the greatest threats to biodiversity, at both the... more Connectivity loss has been identified as one of the greatest threats to biodiversity, at both the species and ecosystem levels. This study aims to find possible correlations between structural connectivity and faunal richness and landscape diversity in Spain's largest region, Castilla y León. Based on data provided by the National Biodiversity Inventory and the CORINE Land Cover land-use mapping for 2000 and 2006, species richness was characterized by the number of species occurring in a grid overlaid on the 10 × 10-km-territory. The Shannon Index for land uses was also calculated in each one of the grid cells, providing information on landscape diversity. Structural connectivity was studied using the Morphological Spatial Pattern Analysis, thus providing information on landscape diversity for different edge widths in two different habitat types. Lastly, the analyses showed that there is a slight relationship between structural connectivity and landscape diversity, but not between structural connectivity and faunal richness.
Tourism is an activity that generates important benefits; in the case of Costa Rica, it focuses i... more Tourism is an activity that generates important benefits; in the case of Costa Rica, it focuses its activity on natural areas, using the different ecosystem services (ES) and obtaining economic and social benefits. However, its ecological value can diminish, making it necessary to implement methods to estimate its sustainability. This paper proposes an evaluation of tourism around ES by applying the MIVES method (Value Integrated Model for Sustainability Evaluation), based on the multi-attribute utility theory, which implies that it transforms different variables into a 0 to 1 relationship, where the closer it is to 1, the more sustainable it is. For this purpose, it considered a decision tree, integrating environmental, economic, and social requirements, 6 criteria, and 13 indicators. The method was applied to two sites, Golfito and Jimenez in Costa Rica. It considered the following stages: (i) literature review and expert consultation, (ii) decision tree, (iii) assignment of weigh...
Cantabrian capercaillie (Tetrao urogallus cantabricus) is listed as endangered according to IUCN ... more Cantabrian capercaillie (Tetrao urogallus cantabricus) is listed as endangered according to IUCN criteria. The high degree of fragmentation and anthropogenic disturbances in capercaillie habitat suggests that habitat patterns may be related to decline of capercaillie populations in northern Spain. The objectives of this study are: (1) determining critical territories for the maintenance of capercaillie connectivity; and (2) evaluating the importance of public forests and their appropriate management to maintain the habitat connectivity for this species. This study is focused on northern Spain, where forest areas are critical for the maintenance of capercaillie. We applied connectivity methodologies based on morphological spatial pattern analysis (MSPA) and the probability of connectivity (PC). The results of the MSPA were incorporated into a standard GIS and compared with the spatial distribution of the public forest. Most of the valuable areas for connectivity were inside the public forests. Moreover, these public forests mainly form continuous features. Therefore, forest planning and management, mainly in public forest, should approach this problem including connectivity considerations and, more specifically, identifying the most critical forest sites for the maintenance of capercaillie habitat.
This paper offers the fundamentals of a space-time reconstruction technique from non timeresolved... more This paper offers the fundamentals of a space-time reconstruction technique from non timeresolved, statistically independent data. An algorithm has been developed to identify and track traveling coherent structures in periodic flows. Flow field phase average is reconstructed with a correlation-based method, similar to POD. This method provides a tool for shedding light on flow dynamics and allows for global dynamics study, instead of being limited to mean statistics or point-based techniques. Flow field phase-average is reconstructed with this novel technique. Noteworthy, the involved computational time is relatively small. Phase-locked average data from time-resolved experiments have been used as a comparison basis. This allows for a direct comparison between real and reconstructed flow fields. Good agreement reveals the method suitability for Particle Image Velocimetry (PIV) measurements. The reconstruction technique is then applied to a set of non time-resolved SPIV measurements in an atmospheric burner, under combustion conditions. Finally, the limitation of the technique applicability to any pseudo periodic flow is further discussed on the basis of the relative modes strength of the Proper Orthogonal Decomposition (POD). The discussion offered allows defining a parameter that indicates the suitability of the technique.
Incorporating risk analysis into physical planning is increasingly necessary to anticipate and ta... more Incorporating risk analysis into physical planning is increasingly necessary to anticipate and take appropriate measures to prevent and defend against disasters. This paper extends the concept of carrying capacity by studying two models: an ecosystem-bringing capacity model and a territorial model of construction on rural land. A climate change variable was integrated into both models, and the changes that occurred depending on the emissions scenario and the time horizons were considered for developing the suitability, impact, and risk models. The data obtained in this study give us an idea of the difficulties that may exist in most of the territory for the construction location on rural land. In fact, only 14% of the occupied study area reaches positive values for the carrying capacity of ecosystems; besides, there are no constructions on rural land located on positive values if we include the risks in the planning. Contextually, assigning a value to the comparable carrying capacity, based on a holistic conception of planning and scientific data, can facilitate the decision-making to initiate future studies and work. Moreover, this study enables to anticipate the effects of climate change when drawing up adaptation and mitigation policies, plans, or programs.
This paper presents a methodology to study the connectivity that livestock trails can offer to gu... more This paper presents a methodology to study the connectivity that livestock trails can offer to guarantee the transit of organisms and access to pasturelands. In this regard, a connectivity analysis was carried out in two scenarios: Basic Scenario (Scenario 1: pasture) and Extended Scenario (Scenario 2: pasture + livestock trails) by using the Morphological Spatial Pattern Analysis (MSPA). The result of structural connectivity analysis, MSPA, showed that livestock trails reduce the fragmentation of the optimal terrain (pasturelands) for livestock activity, since the effective corridors are more numerous, and the edge effect is also reduced. Therefore, MSPA analysis allows the classification of any landscape typology at the pixel level and mapping of corridor structures (connecting elements) and other categories of spatial patterns on a continental scale. The results of the study show the importance of carrying out this type of analysis in different times of the year, detecting the ev...
The space-time dynamics and the effect of urban growth on territory transformation were simulated... more The space-time dynamics and the effect of urban growth on territory transformation were simulated with Iber 2D to analyze flooding events in the lower basin of the Sabinal River, Mexico. We classified the main coverages and land uses of the study area. Soil roughness and water infiltration in the soil were evaluated. Both values were used as input data in a simulation model with Iber 2D to analyze and compare the levels of water height and maximum flood level area with different precipitation values in two reference years, 1986 and 2014. Residential use land cover increased considerably while tree, pasture and agricultural use covers decreased. Consequently, in 2014, precipitation of similar magnitude led to higher values of direct runoff, increasing water levels and therefore the risk of overflowing. The water levels and moments of river overflow provided feedback for flood-risk warning systems and tools to monitor basins lacking adequate infrastructure.
In order to consider forest biomass as a real alternative for energy production, it is critical t... more In order to consider forest biomass as a real alternative for energy production, it is critical to obtain accurate estimates of its availability using non-destructive sampling methods. In this study, we estimate the biomass available in a Scots pine-dominated forest (Pinus sylvestris L.) located in Spain. The biomass estimates were obtained using LiDAR data combined with a multispectral camera and allometric equations. The method used to fuse the data was based on back projection, which assures a perfect match between both datasets. The results present estimates for each of the seven different biomass components: above ground, below ground, log, needles, and large, medium and small branches. The accuracy of the models varied between R 2 values of 0.46 and 0.67 with RMSE% ranging from 15.72% to 35.43% with all component estimates below 20%, except for the model estimating biomass of big branches. The models in this study are suitable for the estimation of biomass and demonstrate that computation is possible at a fine scale for the different biomass components. These remote sensing methods are sufficiently accurate to develop biomass resource cartography for multiple energy uses.
The accurate prediction of forest above-ground biomass is nowadays key to implementing climate ch... more The accurate prediction of forest above-ground biomass is nowadays key to implementing climate change mitigation policies, such as reducing emissions from deforestation and forest degradation. In this context, the coefficient of determination (R 2) is widely used as a means of evaluating the proportion of variance in the dependent variable explained by a model. However, the validity of R 2 for comparing observed versus predicted values has been challenged in the presence of bias, for instance in remote sensing predictions of forest biomass. We tested suitable alternatives, e.g. the index of agreement (d) and the maximal information coefficient (MIC). Our results show that d renders systematically higher values than R 2 , and may easily lead to regarding as reliable models which included an unrealistic amount of predictors. Results seemed better for MIC, although MIC favoured local clustering of predictions, whether or not they corresponded to the observations. Moreover, R 2 was more sensitive to the use of cross-validation than d or MIC, and more robust against overfitted models. Therefore, we discourage the use of statistical measures alternative to R 2 for evaluating model predictions versus observed values, at least in the context of assessing the reliability of modelled biomass predictions using remote sensing. For those who consider d to be conceptually superior to R 2 , we suggest using its square d 2 , in order to be more analogous to R 2 and hence facilitate comparison across studies.
The evaluation of accuracy is essential for assuring the reliability of ecological models. Usuall... more The evaluation of accuracy is essential for assuring the reliability of ecological models. Usually, the accuracy of above-ground biomass () predictions obtained from remote sensing is assessed by the mean differences (), the root mean squared differences (), and the coefficient of determination (2) between observed and predicted values. In this article we propose a more thorough analysis of accuracy, including a hypothesis test to evaluate the agreement between observed and predicted values, and an assessment of the degree of overfitting to the sample employed for model training. Using the estimation of forest from LIDAR and spectral sensors as a case study, we compared alternative prediction and variable selection methods using several statistical measures to evaluate their accuracy. We showed that the hypothesis tests provide an objective method to infer the statistical significance of agreement. We also observed that overfitting can be assessed by comparing the inflation in residual sums of squares experienced when carrying out a cross-validation. Our results suggest that this method may be more effective than analysing the deflation in 2. We proved that overfitting needs to be specifically addressed since, in light of , and 2 alone, predictions may apparently seem reliable even in clearly unrealistic circumstances, for instance when including too many predictor variables. Moreover, Theil's partial inequality coefficients, which are employed to resolve the proportions of the total errors due to the unexplained variance, the slope and the bias, may become useful to detect averaging effects common in remote sensing predictions of. We concluded that statistical measures of accuracy, precision and agreement are necessary but insufficient for model evaluation. We therefore advocate for incorporating evaluation measures specifically devoted to testing observed-versuspredicted fit, and to assessing the degree of overfitting.
In the context of predicting forest attributes using a combination of airborne LIDAR and multispe... more In the context of predicting forest attributes using a combination of airborne LIDAR and multispectral (MS) sensors, we suggest the inclusion of normalized difference vegetation index (NDVI) metrics along with the more traditional LIDAR height metrics. Here the data fusion method consists of back-projecting LIDAR returns onto original MS images, avoiding coregistration errors. The prediction method is based on non-parametric imputation (most similar neighbour). Predictor selection and accuracy assessment include hypothesis tests and overfitting prevention methods. Results show improvements when using combinations of LIDAR and MS compared to using either of them alone. The MS sensor has little explanatory capacity for forest variables dependent on tree height, already well determined from LIDAR alone. However, there is potential for variables dependent on tree diameters and their density. The combination of LIDAR and MS sensors can be very beneficial for predicting variables describing forests structural heterogeneity, which are best described from synergies between LIDAR heights and NDVI dispersion. Results demonstrate the potential of NDVI metrics to increase prediction accuracy of forest attributes. Their inclusion in the predictor dataset may, however, in a few cases be detrimental to accuracy, and therefore we recommend to carefully assess the possible advantages of data fusion on a case-by-case basis.
Uploads
Papers by Ana Hernando