Percorrer por autor "Kreft, Holger"
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- Integrating plot-based methods for monitoring biodiversity in island habitats under the scope of BIODIVERSA+ project BioMonI: Tree monitoring in Terceira, Tenerife and Réunion IslandsPublication . Borges, P.A.V.; Nunes Morgado, Leila; Gabriel, Rosalina; Pires Bento da Silva Elias, Rui Miguel; Gauche, Miharisoa; Ah-Peng, Claudine; Otto, Rüdiger; de Nascimento, Lea; Strasberg, Dominique; Guerrero-Ramírez. Nathaly; Kreft, Holger; Fernández-Palacios, José María; Soares, AntónioABSTRACT: Oceanic islands are globally recognised for their exceptional levels of biodiversity and endemism, often resulting from unique evolutionary processes in isolated environments. However, this biodiversity is also disproportionately threatened by anthropogenic pressures including habitat loss, invasive species and climate change. Targeted, long-term biodiversity monitoring is essential for detecting changes in these vulnerable ecosystems and providing information for conservation strategies. The EU BIODIVERSA + project BioMonI aims at building a global long-term monitoring network specifically tailored to the pressing needs of biodiversity conservation and monitoring on islands. In BioMonI, we use a novel approach that considers mapping previous and current monitoring schemes on islands, developing a harmonised monitoring scheme for island biodiversity and mobilising existing monitoring data. We are assembling data from BioMonI-Plot, a long-term vegetation plot network to understand biodiversity and ecosystem change. It will use baseline data from three focal archipelagos (Azores, Canary Islands and Mascarenes), but we aim to mobilise data from archipelagos worldwide. Plot-based data are a cornerstone of effective biodiversity monitoring on islands. These standardised data collections within permanent plots allow for consistent, replicable observations across temporal and spatial scales. Initiatives like the Global Island Monitoring Scheme (GIMS) highlight the value of permanent plots in capturing ecological gradients and anthropogenic disturbance patterns. Such data underpin the detection of subtle shifts in community composition, functional diversity and species distributions, which are critical for assessing the effectiveness of conservation actions and predicting future ecological scenarios. In summary, plot-based data are indispensable for targeted and effective biodiversity monitoring on islands. They provide the empirical backbone necessary to provide information for adaptive management strategies and contribute to global biodiversity targets.
- Oceanic island biogeography through the lens of the General Dynamic Model : assessment and prospectPublication . Borregaard, Michael K.; Amorim, Isabel R.; Borges, Paulo A. V.; Cabral, Juliano S.; Fernández-Palacios, José María; Field, Richard; Heaney, Lawrence R.; Kreft, Holger; Matthews, Thomas J.; Olesen, Jens M.; Price, Jonathan; Rigal, François; Steinbauer, Manuel J.; Triantis, Konstantinos A.; Valente, Luis; Weigelt, Patrick; Whittaker, Robert J.The general dynamic model of oceanic island biogeography (GDM) has added a new dimension to theoretical island biogeography in recognizing that geological processes are key drivers of the evolutionary processes of diversification and extinction within remote islands. It provides a dynamic and essentially non-equilibrium framework generating novel predictions for emergent diversity properties of oceanic islands and archipelagos. Its publication in 2008 coincided with, and spurred on, renewed attention to the dynamics of remote islands. We review progress, both in testing the GDM’s predictions and in developing and enhancing ecological–evolutionary understanding of oceanic island systems through the lens of the GDM. In particular, we focus on four main themes: (i) macroecological tests using a space-for-time rationale; (ii) extensions of theory to islands following different patterns of ontogeny; (iii) the implications of GDM dynamics for lineage diversification and trait evolution; and (iv) the potential for downscaling GDM dynamics to local-scale ecological patterns and processes within islands. We also consider the implications of the GDM for understanding patterns of non-native species diversity. We demonstrate the vitality of the field of island biogeography by identifying a range of potentially productive lines for future research.
- Scientists’ Warning - The Outstanding Biodiversity of Islands is in PerilPublication . Fernández-Palacios, José María; Kreft, Holger; Irl, Severin D. H.; Norder, Sietze J.; Ah-Peng, Claudine; Borges, Paulo A. V.; Burns, Kevin C.; Nascimento, Lea de; Meyer, Jean-Yves; Montes, Elba; Drake, Donald R.Despite islands contributing only 6.7% of land surface area, they harbor ~20% of the Earth’s biodiversity, but unfortunately also ~50% of the threatened species and 75% of the known extinctions since the European expansion around the globe. Due to their geological and geographic history and characteristics, islands act simultaneously as cradles of evolutionary diversity and museums of formerly widespread lineages—elements that permit islands to achieve an outstanding endemicity. Nevertheless, the majority of these endemic species are inherently vulnerable due to genetic and demographic factors linked with the way islands are colonized. Here, we stress the great variation of islands in their physical geography (area, isolation, altitude, latitude) and history (age, human colonization, human density). We provide examples of some of the most species rich and iconic insular radiations. Next, we analyze the natural vulnerability of the insular biota, linked to genetic and demographic factors as a result of founder events as well as the typically small population sizes of many island species. We note that, whereas evolution toward island syndromes (including size shifts, derived insular woodiness, altered dispersal ability, loss of defense traits, reduction in clutch size) might have improved the ability of species to thrive under natural conditions on islands, it has simultaneously made island biota disproportionately vulnerable to anthropogenic pressures such as habitat loss, overexploitation, invasive species, and climate change. This has led to the documented extinction of at least 800 insular species in the past 500 years, in addition to the many that had already gone extinct following the arrival of first human colonists on islands in prehistoric times. Finally, we summarize current scientific knowledge on the ongoing biodiversity loss on islands worldwide and express our serious concern that the current trajectory will continue to decimate the unique and irreplaceable natural heritage of the world’s islands. We conclude that drastic actions are urgently needed to bend the curve of the alarming rates of island biodiversity loss.
- Snapshot isolation and isolation history challenge the analogy between mountains and islands used to understand endemismPublication . Flantua, Suzette G. A.; Payne, Davnah; Borregaard, Michael K.; Beierkuhnlein, Carl; Steinbauer, Manuel J.; Dullinger, Stefan; Essl, Franz; Irl, Severin D. H.; Kienle, David; Kreft, Holger; Lenzner, Bernd; Norder, Sietze; Rijsdijk, Kenneth F.; Rumpf, Sabine B.; Weigelt, Patrick; Field, RichardAIM: Mountains and islands are both well known for their high endemism. To explain this similarity, parallels have been drawn between the insularity of "true islands" (land surrounded by water) and the isolation of habitats within mountains (so-called "mountain islands"). However, parallels rarely go much beyond the observation that mountaintops are isolated from one another, as are true islands. Here, we challenge the analogy between mountains and true islands by re-evaluating the literature, focusing on isolation (the prime mechanism underlying species endemism by restricting gene flow) from a dynamic perspective over space and time. FRAMEWORK: We base our conceptualization of "isolation" on the arguments that no biological system is completely isolated; instead, isolation has multiple spatial and temporal dimensions relating to biological and environmental processes. We distinguish four key dimensions of isolation: (a) environmental difference from surroundings; (b) geographical distance to equivalent environment [points (a) and (b) are combined as "snapshot isolation"]; (c) continuity of isolation in space and time; and (d) total time over which isolation has been present [points (c) and (d) are combined as "isolation history"]. We evaluate the importance of each dimension in different types of mountains and true islands, demonstrating that substantial differences exist in the nature of isolation between and within each type. In particular, different types differ in their initial isolation and in the dynamic trajectories they follow, with distinct phases of varying isolation that interact with species traits over time to form present-day patterns of endemism. CONCLUSIONS: Our spatio-temporal definition of isolation suggests that the analogy between true islands and mountain islands masks important variation of isolation over long time-scales. Our understanding of endemism in isolated systems can be greatly enriched if the dynamic spatio-temporal dimensions of isolation enter models as explanatory variables and if these models account for the trajectories of the history of a system.