1,721,069 research outputs found
Network science: applications for sustainable agroecosystems and food security
Get PDFArtículo realizado por más de veinticinco autores.The global challenge of feeding two billion more people by 2050, using more sustainable agricultural practices whilst dealing with uncertainties associated with environmental change, requires a transformation of food systems. We present a new perspective for how advances in network science can provide novel ways to better understand, harness, and restore multiple ecological processes in agricultural environments. We describe: (i) a network-focused framework for managing agro-ecosystems that accounts for the multiple interactions between biodiversity and associated ecosystem services; (ii) guidance for incorporating socio-economic factors into ecological networks; and (iii) the potential to upscale network methods to inform efforts to build resilience, including global food-supply chains. In doing so we aim to facilitate the application of network science as a systems-based way to tackle the challenges of securing an equitable distribution of food
Disrupted montane forest recovery hinders biodiversity conservation in the tropical Andes
No full textAim: Andean montane forests are biodiversity hotspots and large carbon stores and they provide numerous ecosystem services. Following land abandonment after centuries of forest clearing for agriculture in the Andes, there is an opportunity for forest recovery. Field-based studies show that forests do not always recover. However, large-scale and long-term knowledge of recovery dynamics of Andean forests remains scarce. This paper analyses tropical montane forest recovery trajectories over a 15-year time frame at the landscape and tropical Andean scale to inform restoration planning.Methods: we first detect “potential recovery” as areas that have experienced a forest transition between 2000 and 2005. Then, we use Landsat time series analysis of the normalized difference water index (NDWI) to classify four “realized recovery” trajectories (“ongoing”, “arrested”, “disrupted” and “no recovery”) based on a sequential pattern of 5-yearly Z-score anomalies for 2005–2020. We compare these results against an analysis of change in tree cover to validate against other datasets.Results: across the tropical Andes, we detected a potential recovery area of 274 km2 over the period. Despite increases in tree cover, most areas of the Andes remained in early successional states (10–25% tree cover), and NDWI levelled out after 5–10 years. Of all potential forest recovery areas, 22% showed “ongoing recovery”, 61% showed either “disrupted” or “arrested recovery”, and 17% showed “no recovery”. Our method captured forest recovery dynamics in a Peruvian arrested succession context and in landscape-scale tree-planting efforts in Ecuador.Main conclusions: forest recovery across the Andes is mostly disrupted, arrested or unsuccessful, with consequences for biodiversity recovery and provision of ecosystem services. Low-recovery areas identified in this study might be good candidates for active restoration interventions in this UN Decade on Restoration. Future studies could determine restoration strategies and priorities and suggest management strategies at a local planning scale across key regions in the biodiversity hotspot
) in an African savanna at high temporal resolution
Get PDFDetermining the drivers of aboveground net primary production (ANPP), a key ecosystem process, is an important goal of ecosystem ecology. However, accurate estimation of ANPP across larger areas remains challenging, especially for savanna ecosystems that are characterized by large spatiotemporal heterogeneity in ANPP. Satellite remote sensing methods are frequently used to estimate productivity at the landscape scale but generally lack the spatial and temporal resolution to capture the determinants of productivity variation. Here, we developed and tested methods for estimating herbaceous productivity as an alternative to labour-intensive repeated biomass clipping and caging of small plots. We compared measures of three spectral greenness indices, normalized difference vegetation index derived from Sentinel-2 (NDVIs) and a handheld radiometer (NDVIg), and green chromatic coordinate derived from digital repeat cameras (GCC) and tested their relationship to biweekly field-measured herbaceous ANPP using movable exclosures. We found that a satellite-based model including average NDVIs and its rate of change (ΔNDVIs) over the biweekly productivity measurement interval predicted herbaceous ANPP reasonably well (Jackknife R2 = 0.26). However, the predictive accuracy doubled (Jackknife R2 = 0.52) when including the sum of day to day increases in camera trap-derived vegetation greenness (tGCC). This result can be considered promising, given the current lack of productivity estimation methods at comparable spatiotemporal resolution. We furthermore found that the fine (daily) temporal resolution of GCC time series captured fast vegetation responses to rainfall events that were missed when using a coarser temporal resolution (>2 days). These findings demonstrate the importance of measuring at a fine temporal resolution for predicting herbaceous ANPP in savanna ecosystems. We conclude that camera traps are promising in offering a reliable and cost-effective method to estimate productivity in savannas and contribute to a better understanding of ecosystem functioning and its drivers
Modelling the potential distribution of tree species at the national scale using geographical information systems
No full textEThOS - Electronic Theses Online ServiceGBUnited Kingdo
Fire-induced loss of the world's most biodiverse forests in Latin America
Get PDFNAS Subaward Letters nos. 2000007526 and 2000010972 awarded to D.A. The Chilean National of Scientific and Technological Research (CONICYT) with Project Formacion de Redes Internacionales para Investigadores en Etapa Inicial N degrees REDI170329 awarded to A.H.-M. L.M.D. was supported in part by NSF-DGE 1633299
Fire and Water: Global Change, Forest Resilience, and the Risk of the Amazon Tipping Point
No full textGlobal South leadership towards inclusive tropical ecology and conservation
No full texthttp://dx.doi.org/10.13039/100018928 Westlake Universityhttp://dx.doi.org/10.13039/501100003385 Georg-August-Universität Göttinge
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Patrones del paisaje y escenarios de restauración: acercando escalas
Get PDFEl paisaje, entendido como un mosaico heterogéneo, es una unidad donde interactúan ecosistemas, especies y el hombre con el uso que este último hace del mismo. El paisaje es el resultado de complejas interacciones, no solo producto de dinámicas naturales sino del balance de la oferta y la demanda de la sociedad ante la preferencia por los recursos que este ofrece. Este equilibrio causa impactos ecológicos sobre los ecosistemas y la diversidad de organismos que ocupan los paisajes. El uso y manejo del territorio aumenta la heterogeneidad espacial, en muchos casos a través de la pérdida y fragmentación de hábitat. Estos procesos traen alteraciones sobre el funcionamiento de los ecosistemas, afectando funciones y procesos ecológicos que dependen del flujo de energía y materiales a través de paisajes. El objetivo de este trabajo es avanzar en la comprensión de los orígenes de la heterogeneidad resultante de estas dinámicas, para mitigar sus efectos y entender cómo planificar y manejar los paisajes. Restaurar, rehabilitar y recuperar ecosistemas son estrategias para asegurar la conservación, sostenibilidad y en algunos casos la recuperación de servicios ecosistémicos. En ocasiones las escalas de paisaje y aquellas a las cuales se realizan actividades de restauración se encuentran alejadas en la práctica. Este artículo presenta una revisión de conceptos claves en ecología del paisaje y de restauración, acercando escalas intrínsecas de los fenómenos y de toma de decisiones para el desarrollo de escenarios de manejo y restauración en Colombia
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