Papers by Silvia Flaherty
Implementation of a general linear model using LiDAR derived explanatory variables: a case study in Scotland
Proceedings of SPIE, Oct 19, 2012
ABSTRACT The native Eurasian red squirrel is considered endangered in the UK and under strict leg... more ABSTRACT The native Eurasian red squirrel is considered endangered in the UK and under strict legal protection. Long term habitat management is a key goal of the UK conservation strategy. The importance of forest structural parameters for red squirrels habitat mapping was previously demonstrated: a General Linear Model (GLM) was used to relate the number of cones stripped by squirrels to mean canopy closure, mean tree height and total number of trees at the plot level, all significant predictors and explaining 43% of the variance in the number of stripped cones. The main aim of this study is to implement the GLM using LiDAR derived explanatory variables and to assess habitat suitability at Abernethy Forest, one of the proposed red squirrel strongholds in the UK. LiDAR-based GLM performance was explored by assessing the correlation between field-predicted and LiDAR-predicted number of stripped cones (Spearman rank correlation coefficient = 0.59; n=32, P< 0.00). Finally, habitat suitability maps were generated. Results suggest that when forest structure is considered, only 27% of the total forest area at Abernethy is suitable for red squirrel.
Limnologica, 2019
Stream water quality is directly influenced by land use and human practices in the surrounding en... more Stream water quality is directly influenced by land use and human practices in the surrounding environment. Understanding such effects and the spatial extent of impacts is essential to generate reliable information for ecosystem-based management of water resources. We identified sources of impact on water quality and characterized indicator-specific landscape influence on samples collected during base flow along the Chubut River (43ºS, 69ºW). We modeled Total Nitrogen (TN), Total Phosphorous (TP), Soluble Reactive Phosphorous (SRP) concentrations and 15 N of particulate organic matter along the river, as a function of effective contribution areas (AEC) of Land Use/Land Cover (LULC). AECs were calculated by assuming that landscape influence decays exponentially with the Euclidean distance between a given LULC parcel and the sampling point. We calibrated the model to the observations by estimating an indicatorspecific decay rate. Agriculture and barren lands were the main sources of phosphate nutrients whereas urban areas were the main source of TN. Radius of landscape influence for SRP (100-180 km) was larger than for TP (10-25 km), reflecting different patterns of mobilization and delivery in the catchment. 15 N variation was explained by vegetation cover but the influence rapidly decreased (1-4 km) reflecting a mostly autochthonous source of organic matter.
Forestry, May 20, 2012
The aim of this study was to assess the effect of cytokinins not commonly used for shoot inductio... more The aim of this study was to assess the effect of cytokinins not commonly used for shoot induction from zygotic embryos of Pinus radiata D. Don. The influence of in vitro shoot and root induction treatments on the subsequent ex vitro development of the regenerated plants was also tested. Embryos were cultured with benzyladenine (BA), thidiazuron (T) and two cytokinins not previously assayed in radiata pine organogenesis (meta-topolin (m-T) and zeatin (Z)) in a range of concentrations and induction periods. Shoot induction treatments were assayed in seeds from different geographical origins to obtain wider conclusions. We analysed the effect of these cytokinin treatments on in vitro rooting with different auxins ((indole-3-butyric acid (IBA) and 1-naphtalene acetic acid (NAA)) and the traditionally used mixture. After in vitro rooting, the plantlets were acclimatized and their ex vitro behaviour was evaluated. Shoot induction treatments with 1 μM BA for 2 weeks, 4.4 μM BA for 3 weeks or 1 μM Z for 3 weeks were more effective than the other treatments. An interaction between in vitro shoot and root induction treatments was observed. IBA was more efficient for plant production because the explants rooted in this auxin had better survival rates in the greenhouse.
Producción de agua en la Cuenca del Río Limay: modelado y calibración
Notas Sobre El Balance Hídrico Del Dique Ameghino
Theoretical and Applied Climatology, Feb 8, 2020
The current study presents an assessment of the impact of climate change on water yield, one of t... more The current study presents an assessment of the impact of climate change on water yield, one of the main hydrological ecosystem services, in northern Patagonia. The outputs of regional climate models from the CORDEX Project for South America were used to drive the InVEST water yield model. CORDEX regional climate models project for the far future (2071-2100) an increase in temperature higher than 1.5°C and a precipitation decrease ranging from − 10 to − 30% for the study area. The projected warmer and dryer climate emerges as a robust signal based on model agreement and on consistent physical drivers of these changes. Moreover, both the projected increase in evapotranspiration and the decrease in precipitation contribute to a strong decrease in water yield of around − 20 to − 40% in the headwaters of northern Patagonian watersheds. Comparison of the results in the two basins reveals that the land cover may be considered a buffer of water yield changes and highlights the key role of protected areas in reducing the vulnerability of water resources to climate change.
Forest stand structure and cone crop affect winter habitat use by Eurasian red squirrel (Sciurus vulgaris)
Forest Ecology and Management, Dec 1, 2021
Abstract Food resources are one of the important components of high quality habitat. One way to b... more Abstract Food resources are one of the important components of high quality habitat. One way to better understand the behavioral decisions made by animals to select foraging patches is focusing on the important forest stand structure characteristics. In this study we investigate the relationship between red squirrel habitat preferences, forest characteristics, i.e. distance to forest edge, canopy closure, cover of understory and undergrowth, and estimated cone biomass. We explore for the first time a methodology to predict cone biomass based on allometric equations and the extent to which this parameter affects habitat choice by red squirrels. Using tree measurements to predicted cone biomass at the plot level which is located in a given stand provides a usefulness proxy of food resources and it is not time-consuming compare with the traditional annual cone count. We selected sixty 30-by-30 m plots in mature Norway spruce forest stands where we measured percentage understory cover, percentage undergrowth cover, distance to forest edge, number of Norway spruce trees, diameter at breast height and height of each Norway spruce tree, number of other tree species and percentage of canopy closure. Within each plot, we counted all Norway spruce cones stripped by red squirrels. Results showed that both forest characteristics (i.e. distance to forest edge and canopy closure) and estimated cone biomass were significant predictors of red squirrel feeding signs on Norway spruce. Our study revealed the potential usefulness of cone biomass as a parameter to determine cone productivity of Norway spruce stands. The effects of food abundance and forest stand structure characteristics are crucial for habitat selection by red squirrels. Estimation of cone biomass based on the tree measurement can be useful for predicting potential foraging habitats for red squirrels regardless of the seed year and can be simple to use for conservation practice in order to locate potential sites for protection of this species.
Science of The Total Environment, Dec 1, 2015
• Differences in precipitation over the Andes in Central Patagonia are striking. • The sensitivit... more • Differences in precipitation over the Andes in Central Patagonia are striking. • The sensitivity of water yield modelling to precipitation inputs is large. • Small differences among datasets translate into large differences in water yield. • It is essential to evaluate the uncertainty related to input when modelling ES. • Using the best precipitation data is fundamental for modelling hydrological ES.
El aumento en el uso consuntivo de la tierra y el agua ha resultado en el deterioro de la salud d... more El aumento en el uso consuntivo de la tierra y el agua ha resultado en el deterioro de la salud de los ecosistemas de agua dulce y de los servicios que estos proveen al ser humano, como por ejemplo la calidad del agua y el transporte de nutrientes. Esto hace necesario el uso de nuevas herramientas para apoyar los sistemas de decisión en el manejo de los recursos naturales, estableciendo métodos que relacionen procesos hidrológicos, climáticos, químicos y biológicos a la escala en la cual se toman decisiones. En este contexto, se utiliza el modelo INVEST (Integrated Valuation of Environmental Services and Tradeoffs), que es una herramienta que permite guiar el manejo de los sistemas naturales con el fin de satisfacer las necesidades humanas y a su vez preservar la salud e integridad de los mismos. El estudio se focaliza en la Cuenca del río Chubut, que es el recurso hídrico más importante de la Provincia; su caudal depende principalmente de las precipitaciones que recibe en sus nacientes y atraviesa la meseta patagónica hasta su desembocadura en el Océano Atlántico. En este trabajo se presentan los resultados preliminares de la aplicación del modelo INVEST para analizar la producción de agua
SatRed: New classification land use/land cover model based on multi-spectral satellite images and neural networks applied to a semiarid valley of Patagonia
Remote Sensing Applications: Society and Environment, Apr 1, 2022
Memoria del Primer Encuentro de Actores Territoriales de la Cuenca inferior del Río Chubut, Trelew, 24 de abril de 2019
Use of LiDAR in the conservation management of the endangered red squirrel (<i>Sciurus vulgaris L.</i>)
Journal of Applied Remote Sensing, Jul 14, 2014
ABSTRACT LiDAR remote sensing allows the direct retrieval of vegetation structure parameters and ... more ABSTRACT LiDAR remote sensing allows the direct retrieval of vegetation structure parameters and has been widely used to assess habitat quality for various species. The aim of this study is to test whether LiDAR can help in providing estimates of habitat suitability over larger scales and inform conservation management planning in stronghold areas of an endangered forest mammal, the red squirrel (Sciurus vulgaris L.). The Eurasian red squirrel is endangered in the UK and under strict legal protection. Hence, long-term habitat management is a key goal of the UK conservation strategy. This involves understanding habitat preferences of the species. In a previous study, we demonstrated the importance of forest structure for red squirrels’ habitat preference. We used a general linear model (GLM) to relate the distribution and abundance of squirrel feeding signs to mean canopy closure, mean tree height, and the total number of trees at the plot level. However, this analysis was limited to a few sample areas. In the current study, we implement the GLM using LiDAR-derived explanatory variables in Abernethy Forest. Results suggest that when forest structure is considered, only 27% of the total forest area is highly suitable for red squirrel. Implications for management are discussed
The native Eurasian red squirrel is considered endangered in the UK and is under strict legal pro... more The native Eurasian red squirrel is considered endangered in the UK and is under strict legal protection. Long-term management of its habitat is a key goal of the UK conservation strategy. Current selection criteria of reserves and subsequent management mainly consider species composition and food availability. However, there exists a critical gap in understanding and quantifying the relationship between squirrel abundance, their habitat use and forest structural characteristics. This has partly resulted from the limited availability of structural data along with costefficient data collection methods. This study investigated the relationship between squirrel feeding activity and structural characteristics of Scots pine forests. Field data were collected from two study areas: Abernethy and Aberfoyle Forests. Canopy closure, diameter at breast height, height and number of trees were measured in 56 plots. Abundance of squirrel feeding signs was used as an index of habitat use. A GLM was used to model the response of cones stripped by squirrels in relation to the field collected structural variables. Results show that forest structural characteristics are significant predictors of feeding sign presence, with canopy closure, number of trees and tree height explaining 43% of the variation in stripped cones. The GLM was also implemented using LiDAR data to assess at wider scales the number of cones stripped by squirrels. The use of remote sensing-in particular Light Detection and Ranging (LiDAR)-enables cost efficient assessments of forest structure at large scales and can be used to retrieve the three variables explored in this study; canopy cover, tree height and number of trees, that relate to red squirrel feeding behaviour. Correlation between field-predicted and LiDAR-predicted number of stripped cones was performed to assess LiDAR-based model performance. LiDAR data acquired at Aberfoyle and Abernethy Forests had different characteristics (in particular pulse density), which influences the accuracy of LiDAR derived metrics. Therefore correlations between field predicted and LiDAR predicted number of cones (LSC) were assessed for each study area separately. Strong correlations (r s =0.59 for Abernethy and 0.54 for Aberfoyle) suggest that LiDAR-based model performed relatively well over the study areas. The LiDAR-based model was not expected to
Notas Sobre El Balance Hídrico Del Dique Ameghino
Produccion De Agua en Cuencas Patagónicas: Analisis De Sensibilidad a Distintas Bases De Datos De Uso/Cobertura De Suelo
Producción de agua en la Cuenca del Río Limay: modelado y calibración
Centro Argentino de Meteorólogos, Nov 1, 2018
Universidad Nacional de la Patagonia San Juan Bosco, 2019
Theoretical and Applied Climatology, 2020
The current study presents an assessment of the impact of climate change on water yield, one of t... more The current study presents an assessment of the impact of climate change on water yield, one of the main hydrological ecosystem services, in northern Patagonia. The outputs of regional climate models from the CORDEX Project for South America were used to drive the InVEST water yield model. CORDEX regional climate models project for the far future (2071-2100) an increase in temperature higher than 1.5°C and a precipitation decrease ranging from − 10 to − 30% for the study area. The projected warmer and dryer climate emerges as a robust signal based on model agreement and on consistent physical drivers of these changes. Moreover, both the projected increase in evapotranspiration and the decrease in precipitation contribute to a strong decrease in water yield of around − 20 to − 40% in the headwaters of northern Patagonian watersheds. Comparison of the results in the two basins reveals that the land cover may be considered a buffer of water yield changes and highlights the key role of protected areas in reducing the vulnerability of water resources to climate change.
En este trabajo se realizó un análisis de sensibilidad, calibración y evaluación del desempeño de... more En este trabajo se realizó un análisis de sensibilidad, calibración y evaluación del desempeño del modelo InVEST para simular la producción de agua media anual en la Cuenca del Río Limay. La producción de agua es una servicio ecosistémico hidrológico fundamental que resulta del balance entre la evapotranspiración y la precipitación, dependiendo de las características del suelo y de la cobertura. Las simulaciones permitieron determinar el orden desubcuencas productoras de agua, mostrando que la subcuenca que más produce es la de Aluminé, seguida de la subcuenca Nahuel Huapi. El análisis de sensibilidad a las bases de datos de precipitación evidenció la necesidad de utilizar bases de datos de precipitación con alta resolución espacial y alta densidad de estaciones meteorológicas para este tipo de estudio de modelado a escala de cuenca. La base de datos de precipitación NPCG, generada par aPatagonia Norte con alta densidad de estaciones meteorológicas, dio resultados muy satisfactorios...
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Papers by Silvia Flaherty