Biotic, abiotic, and anthropogenic drivers of demographic performance of non-native Eucalyptus and Pinus species in forested areas of Spain

Non-native trees enhance services that are fundamental for human well-being. Yet, the extensive use of non-native trees has the potential of causing environmental and socio-economic harm. Eucalyptus and Pinus are the most widely distributed and extensively planted tree genera worldwide, because their rapid growth allows profitable production of timber and pulp. Their naturalization is causing severe effects on the environment, but the relative importance of underlying factors determining their demographic performance is not well known. Thus, our aim was to evaluate the relative importance of biotic, abiotic, and anthropogenic factors driving demographic changes of Eucalyptus and Pinus at the regional scale. We compiled environmental variables and demographic data for Eucalyptus globulus, Eucalyptus camaldulensis, and Pinus radiata across 6388 permanent forestland plots surveyed in the Spanish Forest Inventory (SFI). We used the second (1986?1996), third (1997?2007), and fourth (2008?2017) SFI datasets to quantify annual changes in basal area per plot between consecutive inventories (?BA; m2 ha?1 year?1). We also quantified the components of ?BA: tree ingrowth (transitions from juvenile to adult trees), growth, and mortality. We evaluated juvenile recruitment with in-situ regeneration (No. juvenile trees ha?1) within plots already occupied by the focal species in the previous inventory, and with natural colonization of plots where the focal species was absent at the beginning of the time interval. We found that the structure of the biotic community was especially important to explain demographic performance of non-native trees growing in benign environments (E. globulus and P. radiata), whereas abiotic factors were particularly important regulating basal area increments of E. camaldulensis, which occurs in harsher environments. Basal area increments decreased with species and functional richness, heterospecific density, mean annual temperature, and increased with soil capacity to retain nutrients and water. Colonization of new plots increased with propagule availability in the surrounding landscape. Tree cutting was beneficial for P. radiata. Collectively, our results suggest that non-native trees perform better in forests with high propagule pressure, low biotic resistance, favourable abiotic conditions, and human management.Agencia Estatal de InvestigaciónUniversidad de AlcaláMinisterio de Ciencia e InnovaciónComunidad de Madri

Searching for predictors of the variability of impacts caused by non-native trees on regulating ecosystem services worldwide

Humans have introduced non-native trees (NNT) all over the world to take advantage of the plethora of benefits they provide. However, depending on the context, NNT may present a diverse range of effects on ecosystem services (ES), from benefits to drawbacks, which may hinder the development of policies for these species. Unfortunately, the attempts so far to understand the impacts of NNT on ES only explained a low proportion of their variation. Here we analyze the variation in impacts of NNT on regulating ecosystem services (RES) by using a global database, which covers the effect size of multiple NNT species on six RES (climate regulation, soil erosion regulation, soil fertility, soil formation, hydrological cycle regulation, and fire protection). We used a wide range of predictors to account for the context-dependency of impacts distributed in five groups: the RES type, functional traits of both the NNT and the dominant NT of the recipient ecosystem, phylogenetic and functional distances between NNT and NT, climatic context, and human population characteristics. Using boosted regression trees and regression trees, we found that the most influential predictors of NNT impacts on RES were annual mean temperatures and precipitation seasonality, followed by the type of RES, human population density, and NNT height. In regions with warm temperatures and low seasonality, NNT tended to increase RES. NNT impacts were greater in densely populated regions. Smaller NNT exerted greater positive impacts on climate regulation and soil erosion regulation in tropical regions than in other climates. We highlight that benign climates and high population density exacerbate the effects of NNT on RES, and that soil fertility is the most consistently affected RES. Knowledge of the factors that modulate NNT impacts can help to predict their potential effects on RES in different parts of the world and at various environmental setting

Los inventarios forestales nacionales como herramienta para evaluar el estado y la tendencia de las especies exóticas

Las invasiones biológicas son un componente importante del cambio global, el cual está amenazando la biodiversidad y servicios ecosistémicos del planeta. Para gestionar y mitigar los impactos del cambio global, es importante disponer de herramientas de monitorización que permitan evaluar sistemática, periódica, rápida y eficazmente los impactos de las especies exóticas a diversas escalas. Los inventarios forestales nacionales (IFNs) constituyen una herramienta emergente para el seguimiento de la estructura y dinámica de los bosques a grandes escalas espaciales. Los IFNs han sido usados globalmente para evaluar la diversidad biológica, la distribución de especies y el aprovisionamiento de servicios ecosistémicos en bosques. Además, tienen potencial para estudiar diversos aspectos de las invasiones biológicas, tanto desde un punto de vista teórico como aplicado. En este estudio revisamos la bibliografía disponible para conocer qué trabajos sobre especies exóticas se han publicado utilizando IFNs. Encontramos 96 estudios que usaban IFNs para evaluar el estado o dinámica de las especies exóticas en Estados Unidos (74), Europa (20), Canadá (1) y Australia (1). Más de la mitad de los estudios fueron realizados sobre distribución, riesgo de expansión, demografía o impactos de plantas exóticas (64). Los estudios restantes utilizaron IFNs para investigar riesgo de expansión o daños causados por otro tipo de especies exóticas, como insectos (20), patógenos fúngicos o protistas (6), insectos y patógenos (4), ciervos (1) y por el caracol gigante africano (1). Finalmente, discutimos las oportunidades y las limitaciones de los IFNs, resaltando su potencial para ampliar estudios teóricos y aplicados sobre invasiones biológicas.Biological invasions are an important component of global change, which is threatening the planet's biodiversity and ecosystem services. To manage and mitigate the impacts of global change, it is important to have monitoring tools that allow assessing the impacts of exotic species at several scales in a systematic, periodic, rapid, and effective way. National forest inventories (NFIs) are an emerging tool for monitoring forest structure and dynamics at large spatial scales. NFIs have been used globally to assess biological diversity, species distributions, and ecosystem services provision in forests. Moreover, NFIs have the potential to study various theoretical and applied aspects of biological invasions. We conducted a literature review to evaluate what studies about exotic species have been published using information from NFIs. We found 96 studies that used NFIs to assess the status or dynamics of exotic species in the United States (74), Europe (20), Canada (1) and Australia (1). Over half of the studies were conducted on the distribution, expansion risk, demography, or impacts of exotic plants (64). The remaining studies used NFIs to investigate expansion risk or impacts caused by other types of exotic species, including insects (20), fungal or protist pathogens (6), insects and pathogens (4), deer (1) and the giant African land snail (1). Lastly, we discuss the opportunities and limitations of NFIs, highlighting their potential to expand theoretical and applied studies on biological invasions.Agencia Estatal de InvestigaciónMinisterio de Ciencia e InnovaciónFondo Europeo para el Desarrollo Regional-FEDERComunidad de Madri

El papel de las distintas formaciones forestales del Parque Nacional de Monfragüe como reservorios de carbono (Informe técnico)

27 p.En el Parque Nacional de Monfragüe, debido a una larga historia de uso, coexisten en un espacio relativamente pequeño formaciones arbóreas que difieren en la especie dominante, la estructura del bosque y la gestión recibida: dehesas de encina (Quercus ilex subsp. ballota), dehesas de alcornoque (Quercus suber), plantaciones de pino resinero (Pinus pinaster, especie nativa en España, pero introducida en esta región) y plantaciones de eucaliptos (Eucalyptus camaldulensis, especie nativa de Australia). Además, hemos estudiado otra formación de porte arbustivo dominada por jaras (Cistus ladanifer) que resultó de un intento fallido de restaurar plantaciones de eucaliptos hacia bosques de quercíneas. El objetivo del trabajo era comparar la capacidad de almacenamiento de carbono entre estas cinco formaciones, y su distribución entre compartimentos aéreos (biomasa aérea de árboles y arbustos, hojarasca depositada en el suelo) y subterráneos (raíces principales de los árboles, raíces de menor entidad encontradas en el suelo y materia orgánica del suelo en dos profundidades: 0-10 cm y 10-30 cm). Para ello realizamos un muestro de campo en 9-10 parcelas circulares por cada tipo de vegetación, donde medimos las dimensiones de árboles y arbustos, y tomamos muestras de hojarasca, suelos y raíces. Con la ayuda de ecuaciones alométricas y valores de contenido de carbono de la bibliografía o medidos en laboratorio, estimamos el stock de carbono por hectárea en cada compartimento. El pinar fue el tipo de vegetación que más carbono almacena, tanto en la parte aérea como subterránea, debido a la elevada densidad de árboles y a la alta talla de los mismos. Le sigue el eucaliptal, donde la densidad es menor, los árboles son altos, con más signos de decaimiento, pero alberga un sotobosque arbustivo con elevada altura, cobertura y riqueza de especies. A continuación, están las dehesas de encina y alcornoque, con valores menores debido a la baja densidad de árboles y la ausencia casi total de estrato arbustivo. Por último, el matorral, debido a su escaso porte, es el tipo de vegetación que almacena menos carbono, aunque su contenido en el suelo (posiblemente un legado del tipo de vegetación anterior) es similar al de la dehesa. La estructura del pinar y el eucaliptal hacen que estas formaciones sean vulnerables a sufrir incendios, por lo que se recomienda reducir la densidad de árboles del primero y de arbustos en el segundo. En el caso de las dehesas, menos vulnerables a los incendios, resulta patente un problema de regeneración que puede comprometer su futuro a largo plazo. Para ello, se recomienda controlar la presión de herbívoros y realizar plantaciones protegidas de los mismos.Universidad de Alcal

Phenotypic differentiation among native, expansive and introduced populations influences invasion success

Aim: Humans influence species distributions by modifying the environment and by dispersing species beyond their natural ranges. Populations of species that have established in disjunct regions of the world may exhibit trait differentiation from native populations due to founder effects and adaptations to selection pressures in each distributional region. We compared multiple native, expansive and introduced populations of a single species across the world, considering the influence of environmental stressors and transgenerational effects. Location: United States Gulf and Atlantic coasts, United States interior, European Atlantic and Mediterranean coasts, east coast of Australia. Taxon: Baccharis halimifolia L. (eastern baccharis). Methods: We monitored seed germination, seedling emergence, survival and early growth in a common garden experiment, conducted with over 18,200 seeds from 80 populations. We also evaluated the influence of environmental stress and maternal traits on progeny performance. Results: Introduced European Atlantic populations had faster germination and early growth than native populations. However, this was not the case for the more recently naturalized European Mediterranean populations. Introduced Australian populations grew faster than native populations in non-saline environments but had lower survival in saline conditions commonly encountered in the native range. Similarly, expansive inland US populations germinated faster than coastal native populations in non-saline environments but grew and germinated more slowly in saline environments. Maternal inflorescence and plant size were positively related with seed germination and seedling survival, whereas flower abundance was positively correlated with seedling early growth and survival. However, maternal traits explained a much lower fraction of the total variation in early demographic stages of B. halimifolia than did distributional range. Main conclusions: Phenotypic differentiation could allow B. halimifolia to adapt to different biotic and abiotic selection pressures found in each distributional range, potentially contributing to its success in introduced and expansive ranges

Does urbanisation lead to parallel demographic shifts across the world in a cosmopolitan plant?

Urbanisation is occurring globally, leading to dramatic environmental changes that are altering the ecology and evolution of species. In particular, the expansion of human infrastructure and the loss and fragmentation of natural habitats in cities is predicted to increase genetic drift and reduce gene flow by reducing the size and connectivity of populations. Alternatively, the ‘urban facilitation model’ suggests that some species will have greater gene flow into and within cities leading to higher diversity and lower differentiation in urban populations. These alternative hypotheses have not been contrasted across multiple cities. Here, we used the genomic data from the GLobal Urban Evolution project (GLUE), to study the effects of urbanisation on non‐adaptive evolutionary processes of white clover (Trifolium repens) at a global scale. We found that white clover populations presented high genetic diversity and no evidence of reduced Ne linked to urbanisation. On the contrary, we found that urban populations were less likely to experience a recent decrease in effective population size than rural ones. In addition, we found little genetic structure among populations both globally and between urban and rural populations, which showed extensive gene flow between habitats. Interestingly, white clover displayed overall higher gene flow within urban areas than within rural habitats. Our study provides the largest comprehensive test of the demographic effects of urbanisation. Our results contrast with the common perception that heavily altered and fragmented urban environments will reduce the effective population size and genetic diversity of populations and contribute to their isolation

Identification of potential invasive alien species in Spain through horizon scanning

Invasive alien species have widespread impacts on native biodiversity and ecosystem services. Since the number of introductions worldwide is continuously rising, it is essential to prevent the entry, establishment and spread of new alien species through a systematic examination of future potential threats. Applying a three-step horizon scanning consensus method, we evaluated non-established alien species that could potentially arrive, establish and cause major ecological impact in Spain within the next 10 years. Overall, we identified 47 species with a very high risk (e.g. Oreochromis niloticus, Popillia japonica, Hemidactylus frenatus, Crassula helmsii or Halophila stipulacea), 61 with high risk, 93 with moderate risk, and 732 species with low risk. Many of the species categorized as very high or high risk to Spanish biodiversity are either already present in Europe and neighbouring countries or have a long invasive history elsewhere. This study provides an updated list of potential invasive alien species useful for prioritizing efforts and resources against their introduction. Compared to previous horizon scanning exercises in Spain, the current study screens potential invaders from a wider range of terrestrial, freshwater, and marine organisms, and can serve as a basis for more comprehensive risk analyses to improve management and increase the efficiency of the early warning and rapid response framework for invasive alien species. We also stress the usefulness of measuring agreement and consistency as two different properties of the reliability of expert scores, in order to more easily elaborate consensus ranked lists of potential invasive alien species.This work is one of the main results of the InvaNET network (RED2018-102571-T, RED2022-134338-T, https://invasiber.org/InvaNET/), financially supported by MCIN/AEI/10.13039/501100011033. We thank Guido Jones, funded by the Cabildo de Tenerife under the TFinnova Programme supported by MEDI and FDCAN, for revising the English.Peer reviewe

Informe final del escaneo de horizonte sobre futuras especies exóticas invasoras en España

73 p.La introducción de especies exóticas invasoras (EEI) es una de las principales causas de la pérdida de biodiversidad a nivel global, que provoca grandes costes socioeconómicos. Sin embargo, el número de nuevas introducciones continúa creciendo año tras año. Por lo tanto, urge identificar posibles futuras EEI con el objetivo de diseñar e implementar medidas que prevengan y mitiguen los efectos negativos de su introducción. Así, el objetivo de este estudio es prospectar qué especies exóticas no establecidas en España podrían llegar fácilmente en los próximos 10 años, establecerse y causar importantes impactos ecológicos. Para ello, se ha realizado un escaneo de horizonte, siguiendo la metodología establecida en trabajos previos, siendo el primero para el conjunto de las especies exóticas invasoras en España. Se añadieron en el análisis especies que no son autóctonas de España, incluyendo los archipiélagos de Canarias y Baleares, y que no están establecidas en España. Un total de 39 científicos, expertos en distintos grupos taxonómicos y ecosistemas, ha evaluado 933 especies. Con el objetivo de analizar el acuerdo entre las evaluaciones individuales de los expertos y su consistencia, se llevaron a cabo dos análisis de fiabilidad complementarios, cuyos resultados se discuten en este informe. Como resultado del escaneo, se obtuvo una lista priorizada de 105 especies (46 con riesgo muy alto y 59 con riesgo alto). La mayoría de estas especies (84,8%), sin embargo, no están incluidas actualmente en el Catálogo Español de Especies Exóticas Invasoras. Por lo tanto, se recomienda la realización de un análisis de riesgo más detallado de estas especies y, si se confirma el riesgo alto, la solicitud de su incorporación en dicho catálogo o en el Listado de especies alóctonas susceptibles de competir con las especies silvestres autóctonas, alterar su pureza genética o los equilibrios ecológicos. Del mismo modo, se propone la realización de escaneos de horizonte específicos para los archipiélagos de Canarias y Baleares, ya que muchas de las especies autóctonas de la Península no lo son de las islas y podrían tener un gran impacto si allí se introdujeran. Este informe también analiza la afinidad taxonómica (i.e. filo) y funcional (i.e. productor primario, depredador, omnívoro, herbívoro o filtrador) de las especies de la lista priorizada, su origen geográfico y las principales vías de introducción. Por último, discute los mecanismos de impacto de dichas especies.Ministerio de Ciencia e Innovació

Global urban environmental change drives adaptation in white clover

Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by sampling 110,019 white clover plants from 6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors. Urban-rural gradients were associated with the evolution of clines in defense in 47% of cities throughout the world. Variation in the strength of clines was explained by environmental changes in drought stress and vegetation cover that varied among cities. Sequencing 2074 genomes from 26 cities revealed that the evolution of urban-rural clines was best explained by adaptive evolution, but the degree of parallel adaptation varied among cities. Our results demonstrate that urbanization leads to adaptation at a global scale

Evaluating the influence of ecosystem characteristics and species traits on exotic species distributions

Natural dispersal mechanisms and biogeographical barriers have shaped species\u27 native distributional ranges over millions of years. However, over the last few centuries, humans have dispersed species beyond their natural ranges. Those species that undergo explosive population growth and rapid expansion in the introduced region are considered as invasive because they have the potential to cause negative effects on desirable species and/or ecosystem services. In chapter II, I identified what ecosystem characteristics are more closely associated with successful establishment of exotic and native species, to have a better idea of where to concentrate our efforts and resources to prevent invasion events while preserving native species. I found that native and exotic species were differently affected by ecosystem properties. Exotic species were favored by human activities and low native species abundance and diversity. However, in Chapter III, I found that species functional traits, such as growth form and phenology, are more important to explain their response to ecosystem characteristics than native status under certain circumstances. The abundance and reproductive capacity of the evaluated plants were reduced when disturbances occurred during their respective active growing periods. This finding suggests that we need to have into account species-specific responses to ecosystem characteristics when managing biological invasions. Chapter IV examined phenotypic differentiation of native, expansive, and introduced populations of Baccharis halimifolia L. occurring in different regions of the world. The results suggest that there are significant phenotypic differences in germination and early growth among native, expansive, and introduced populations, which could have contributed to the success of B. halimifolia in the introduced and expansive ranges. Finally, in Chapter V, I used the information that I learned in the past projects to predict the spread of 45 exotic plants across southeastern United States and evaluated what landscape factors make an area more susceptible to be invaded. I found that the influence of landscape composition and configuration on invasion risk is species-specific. This result suggests that not only we have to consider species functional traits when managing biological invasions, as we saw earlier in the experiment with disturbance timing, but also species habitat preferences