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Global environmental changes are affecting both the distribution and abundance of species at an unprecedented rate. To assess these effects, species distribution models (SDMs) have been greatly developed over the last decades, while species abundance models (SAMs) have generally received less attention even though these models provide essential information for conservation management. With population abundance defined as an essential biodiversity variable (EBV), SAMs could offer spatially explicit predictions of species abundance across space and time. Satellite-derived ecosystem functioning attributes (EFAs) are known to inform on processes controlling species distribution, but they have not been tested as predictors of species abundance. In this study, we assessed the usefulness of SAMs calibrated with EFAs (as process-related variables) to predict local abundance patterns for a rare and threatened species (the narrow Iberian endemic ‘Gerês lily’ Iris boissieri; protected under the European Union Habitats Directive), and to project inter-annual fluctuations of predicted abundance. We compared the predictive accuracy of SAMs calibrated with climate (CLI), topography (DEM), land cover (LCC), EFAs, and combinations of these. Models fitted only with EFAs explained the greatest variance in species abundance, compared to models based only on CLI, DEM, or LCC variables. The combination of EFAs and topography slightly increased model performance. Predictions of the inter-annual dynamics of species abundance were related to inter-annual fluctuations in climate, which holds important implications for tracking global change effects on species abundance. This study underlines the potential of EFAs as robust predictors of biodiversity change through population size trends. The combination of EFA-based SAMs and SDMs would provide an essential toolkit for species monitoring programs., This work has been carried out within the H2020 project ECOPOTENTIAL: Improving Future Ecosystem Benefits Through Earth Observations (http://www.ecopotential-project.eu). The project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 641762. S.A.-C., D.A.-S., and J.H. received funding from the ECOPOTENTIAL project. A.R. was financially supported by the Xunta de Galicia, Spain (post-doctoral fellowship ED481B2016/084-0). J.F.G. was funded by the Individual Scientific Employment Stimulus Program (2017) by the Portuguese Foundation for Science and Technology (FCT CEEC-2017).

[Resumo] Os rápidos cambios ambientais que se están a producir a nivel global afectan de forma directa á distribución e abundancia das especies. Isto converte á conservación nun dos principais obxectivos da ecoloxía moderna. Detectar a tempo estes cambios é fundamental á hora de establecer medidas efectivas de conservación. A teledetección representa unha ferramenta imprescindible, pero aínda pouco desenvolta, para o estudo a diferentes escalas espaciais e temporais, do hábitat reprodutor de especies ameazadas. Neste traballo modelizamos o hábitat reprodutor da píllara das dunas (Charadrius alexandrinus), a cal presenta tendencias poboacionais que indican un forte declive a curto prazo en España. A partir do arquivo histórico da misión Landsat, obtivéronse índices espectrais de vexetación e contido en auga que permitiron caracterizar anualmente cada praia de posible nidificación. Estas variables foron incluídas como preditores nun modelo lineal xeneralizado mixto, co obxectivo de explicar a variación especiotemporal no número de parellas da píllara das dunas en Galicia nun período de 22 anos (1999-2020). Os resultados confirman que as variables preditoras obtidas por teledetección, que caracterizan a vexetación, o contido en auga ou a reflectividade do solo, presentan unha alta capacidade explicativa da variación no número de parellas nidificantes de píllara das dunas na costa galega (R2 marxinal = 0,5; R2 condicional = 0,757). Das 11 variables non correlacionadas incluídas no modelo, 7 resultaron significativas, 4 fan referencia ao contido en auga (MSAVI_mean, NDWI_min, MNDWI_range e NDWI2_sd) e as 3 restantes están relacionadas co estado da vexetación e a diferenciación entre esta e o solo nu (MSAVI_mean, EVI_max e EVI2_max). Este traballo confirma a utilidade e o potencial da teledetección para modelizar as variacións espaciotemporais en parámetros chave da nidificación da píllara das dunas na costa de Galicia. [Resumen] Los rápidos cambios ambientales que se están produciendo a nivel global afectan de forma directa a la distribución y la abundancia de las especies. Esto convierte a la conservación en uno de los principales objetivos de la ecología moderna. Detectar a tiempo estos cambios es fundamental a la hora de establecer medidas eficaces para la conservación. La teledetección representa una herramienta imprescindible pero todavía poco desarrollada, para el estudio a diferentes escalas espaciales y temporales, del hábitat reproductor de especies ameazadas. En este trabajo modelizamos el hábitat reproductor del chorlitejo patinegro (Charadrius alexandrinus), el cual presenta tendencias poblacionales que indican un fuerte declive a corto plazo en España. A partir del archivo histórico de Landsat, se obtuvieron índices espectrales de vegetación y contenido en agua que permitieron caracterizar anualmente cada playa de posible nidificación. Estas variables fueron incluidas como predictores en un modelo lineal generalizado mixto, con el objetivo de explicar la variación espaciotemporal en el número de parejas de chorlitejo patinegro en Galicia en un período de 22 años (1999-2020). Los resultados confirman que las variables predictoras obtenidas por teledetección, que caracterizan la vegetación, el contenido en agua o la reflectividad del suelo, presentan una alta capacidad explicativa de la variación en el número de parejas de chorlitejo patinegro en la costa gallega (R2 marginal = 0,5; R2 condicional = 0,757). De las 11 variables no correlacionadas incluidas en el modelo, 7 resultaron significativas, 4 hacen referencia al contenido en agua (MSAVI_mean, NDWI_min, MNDWI_range e NDWI2_sd) y las 3 restantes están relacionadas con el estado de la vegetación y la diferenciación entre esta y el suelo desnudo (MSAVI_mean, EVI_max e EVI2_max). Este trabajo confirma la utilidad y el potencial de la teledetección para modelizar las variaciones espaciotemporales en parámetros clave de la nidificación del chorlitejo patinegro en la costa de Galicia. [Abstract] The rapid environmental changes taking place globally directly affect the distribution and abundance of species. This makes conservation one of the main objectives of modern ecology. Detecting these changes on time is essential when establishing effective measures for conservation. Remote sensing represents an essential but still underdeveloped tool for the study at different spatial and temporal scales of the reproductive habitat of threatened species. In this study we model the breeding habitat of the Kentish Plover (Charadrius alexandrinus), which shows population trends that indicate a strong short-term decline in Spain. From Landsat historical archive, spectral indices of vegetation and water content were obtained that allowed each beach of posible nesting to be characterized annually. These variables were included as predictors in a generalized linear mixed model, with the aim of explaining spatio-temporal variation in the number of pairs of Kentish Plover in Galicia over a 22 years period (1999-2020). The results confirm that the predictor variables obtained by remote sensing, which caracterize the vegetation, the water content or the soil reflectance, have a hight explanatory capacity of the variation in the number of pairs of Kentish Plover on the Galician coast (marginal R2 = 0.5; conditional R2 = 0.757). Of the 11 uncorrelated variables included in the model, 7 resulted singnificant, 4 of them refer to the water content (MSAVI_mean, NDWI_min, MNDWI_range e NDWI2_sd) and the remaining 3 are related to the state of vegetation and the differentiation between it and the bare soil (MSAVI_mean, EVI_max e EVI2_max). This study confirms the usefulness and potential of remote sensing to model spatio-temporal variation in key parameters of Kentish Plover nesting on the Galcian coast. Traballo fin de mestrado (UDC.CIE). Biodiversidade terrestre. Curso 2021/2022

The combined effects of climate change and other factors, such as land-use change or fire disturbance, pose daunting challenges for biodiversity conservation world-wide. We predicted the future effectiveness of the Natura 2000 (N2000), the current network of protected areas (PA) in Europe, at maintaining and representing suitable environmental conditions for a set of 79 bird species between 2000 and 2050 in a fire-prone area, strongly affected by land abandonment processes in North East Spain. We then compared PA performance with a set of alternative priority areas for conservation, which consider fire-vegetation dynamics, selected by using a conservation planning tool (Marxan). Fire-vegetation dynamics were modelled using a process-based model (Medfire Model) under alternative fire management and climate change scenarios. Bird communities were predicted using the spatially explicit species assemblage modelling framework (SESAM) and species distribution models that hierarchically integrate climate change and wildfire-vegetation dynamics. The amount of suitable environmental conditions within the N2000 network was predicted to fall by around 15%, on average, over the next decades in relation to the initial conditions but could be partially modulated by fire management policies in future. The efficiency of the current PA system was predicted to decrease from 17.4% to 15% between 2000 and 2050. However, a more efficient PA system could be achieved with a conservation planning approach that explicitly considers fire-vegetation dynamics and their management. Synthesis and applications. Our findings show: (a) how the current Natura 2000 could still hold an important bird conservation value by 2050; (b) how the relocation of some protected areas should be considered in order to substantially increase bird conservation effectiveness; and (c) how the integration of fire-vegetation dynamics, fire management policies and their objectives within conservation planning provide “win–win” solutions for bird conservation and fire prevention in fire-prone abandoned landscapes., This work was partly funded by the projects EU BON (308454; FP7-ENV-2012, European Commission), FORESTCAST (CGL2014-59742), INFORMED (FORESTERRA ERA-NET 29183) and NEWFORESTS (EU Seventh Framework Programme, PIRSES-GA-2013-612645). A.R. is funded by the Xunta de Galicia (post-doctoral fellowship ED481B2016/084-0). V.H. also received funding support provided by the Spanish Government through a Ramon y Cajal contract (RYC-2013-13979).