Search

To understand the effects of invasive species on soil hydraulic properties is a challenging task for Neotropical dry ecosystems because the relative paucity of knowledge of linkages between functional traits of species in response to drought conditions and land-cover transformation contexts. We tested whether functional strategies vary between native and invasive plants and if these differences have impact on processes at ecosystem level. Eight functional traits in wood and leaves of all woody species reported in our study area were measured. Over two contrasting climatic seasons and three vegetation covers, we measured four water regulation properties of soils. We found that forest covers showed higher values of hydraulic conductivity, water infiltration rate, volumetric water content and lower penetration resistance (lower compaction) of soils for both climatic seasons than other vegetation covers. In contrast, zones dominated by invasive species and degraded covers showed greater similarity between hydraulic properties in the soil and high variation among climatic seasons. Additionally, evergreen and deciduous species were functionally different, and invasive evergreen legumes were characterized by acquisitive hydraulic traits but leaf, height and wood density related with conservative strategies. The dominance of functional traits, mainly hydraulic traits, was correlated with volumetric moisture content of the soil. The functional differences between invasive and native species explained the lower soil moisture and greater soil compaction values in invasive covers compared to the forest covers. These results confirm that introduction of invasive species have an impact on soil ecosystem properties on tropical dry forests. Additionally, it is possible that invasive species can help to recover some hydraulic properties and can facilities the restoration processes in degraded areas where the native species failed to colonize.

Although one-quarter of plant and vertebrate species are threatened with extinction, little is known about the potential effect of extinctions on the global diversity of ecological strategies. Using trait and phylogenetic information for more than 75,000 species of vascular plants, mammals, birds, reptiles, amphibians, and freshwater fish, we characterized the global functional spectra of each of these groups. Mapping extinction risk within these spectra showed that larger species with slower pace of life are universally threatened. Simulated extinction scenarios exposed extensive internal reorganizations in the global functional spectra, which were larger than expected by chance for all groups, and particularly severe for mammals and amphibians. Considering the disproportionate importance of the largest species for ecological processes, our results emphasize the importance of actions to prevent the extinction of the megabiota., C.P.C., A.T., M.P., and R.T. were supported by the Estonian Ministry of Education and Research (PSG293, IUT20-29, PRG609, and PSG505) and the European Regional Development Fund (Centre of Excellence EcolChange). M.V.-V. and R.G.-M. were supported by the Dora Plus Fellowship Programme (University of Tartu). S.B. was supported by “Investissement d’Avenir” grants (CEBA, ANR-10-LABX-0025 and TULIP, ANR-10-LABX-41). R.S.-G. was supported by NERC IRF NE/M018458/1. F.d.B. was supported by the Plan Nacional de I+D+i (project PGC2018-099027-B-I00).

Although one quarter of the species of plants and vertebrates are threatened with extinction, little is known about how the potential effect of extinctions on the global diversity of ecological strategies. Using trait and phylogenetic information for more than 75,000 species of plants, mammals, birds, reptiles, amphibians and freshwater fishes, we characterized the global functional spectra of each of these groups. Mapping of extinction risk within these spectra revealed that larger species with slower pace of life are universally threatened. Simulated potential extinctions revealed extensive internal reorganizations in the global functional spectra, which are particularly severe for mammals and amphibians. Considering the disproportionate importance of the largest species for ecological processes, our results emphasize the importance of actions to prevent the extinction of the megabiota.

Biological invasions are the second most important cause of biodiversity loss in the world. Invasive species successfully compete with native species and in most cases negatively affect invaded ecosystems. Several studies have focused on identifying wich characteristics promote the invasiveness of the species and resulting ecological impacts, yet few have assessed how land cover transformation enables colonization of species that are tolerant to limited resources, and if this condition is a driver for biological invasion. To establish the invasibility of a dry ecosystem such as the one in the Magdalena River Valley, the change in vegetation cover in areas currently dominated by species with invasive potentials ( Vachellia farnesiana , Leucaena leucocephala , and Prosospis juliflora ) was analyzed for a period of approximately 70 years. Obtained results show that areas colonized by potentially invasive species had greater transformation dynamics, based on land cover persistence through time. In contrast, forest areas, which lack potentially invasive species, only presented one transformation period and more than 50 years of ecosystem recovery. These results show how ecosystems historically transformed and disturbed can facilitate species invasion processes.

Esta tercera entrega del reporte anual de la biodiversidad en Colombia profundiza en la linea editorial iniciada el ano 2014 mediante nuevas propuestas analiticas y graficas, con la intencion de garantizar que la informacion llegue a todos los publicos y pueda ser discutida de manera amena sin sacrificio de calidad. La apuesta comunicativa sigue siendo central en el proyecto institucional y los nuevos lenguajes con los que estamos aprendiendo a conversar con la sociedad y las instituciones son un experimento que esperamos sea cada vez mas satisfactorio: ya estamos construyendo la version 2017 con el apoyo de las nuevas tecnologias digitales de manera que la potencia de la conexion vital colombiana se exprese en toda su capacidad. Por los contenidos es evidente que aun distamos mucho de tener una capacidad de seguimiento sistematico para la mayoria de temas relativos a la gestion de la biodiversidad y los servicios ecosistemicos, la unica manera de evaluar si las medidas de politica y las inversiones que realiza la sociedad estan teniendo los efectos deseados. De hecho, parte de las limitaciones reconocidas por robustamente los cambios positivos o negativos que afectan los diferentes niveles de organizacion de la vida planetaria, por lo cual las mismas metas de Aichi, nuestra carta de navegacion global, estan pendientes de verificacion. Un proposito adicional de este proceso es la invitacion a todos los colombianos para contribuir con la construccion y alimentacion de los indicadores basicos de seguimiento a la gestion, ya que es imposible identificar las tendencias de largo plazo en que estan inmersas la flora y fauna colombianas sin el apoyo de las instituciones, los investigadores y los ciudadanos: en el pais de la megadiversidad, el reto es inmenso. Por este motivo, este reporte ira abriendo sus paginas a expertos, incluso indigenas o de comunidades locales, para que presenten de manera sistematica y documentada sus perspectivas del cambio ambiental y sus efectos en la biodiversidad, con el animo de promover el compromiso de todos en su gestion. La unica manera de superar el riesgo de extincion es mediante un activo proceso de aprendizajes sociales que haga que todos los sectores asuman una parte de la compleja responsabilidad que significa proteger todas las formas de vida del pais, una decima parte mal contada de las planetarias. Agradezco a las decenas de personas que contribuyeron con este reporte, a quienes nos han apoyado en todas las etapas de produccion y a sus lectores y usuarios, quienes son en ultimo termino los jueces de su utilidad.