Periodic Reporting for period 1 - TIME-LINES (Island TIME-LINES to quantify biodiversity change)
Période du rapport: 2022-10-01 au 2025-03-31
Context
Global biodiversity is changing at an unprecedented rate, posing significant challenges for ecosystem stability and conservation efforts. Despite the urgency of this issue, our understanding of long-term biodiversity dynamics remains limited. The TIME-LINES project aims to investigate the dynamics of biodiversity change on islands globally over the past 5000 years, using them as model systems and biodiversity hotspots with varied human colonization times and impacts. This global approach will enable the development of palaeoecological networks spanning multiple biogeographical scales (islands, archipelagos, biogeographical regions, global).
Appraoch
Our lab has made a breakthrough in understanding biodiversity change by creating a detailed 'Plaeoecological Llibrary' that includes published records from islands around the world, making it a unique resource. Additionally, we employ a multi-proxy approach, integrating fossil pollen analysis with cutting-edge sedimentary DNA (sedaDNA) techniques. This combination allows for a more robust and detailed reconstruction of past ecosystems than either method alone. In addition, our analyses extend beyond biodiversity dynamics to include chronologies of key drivers of ecological change, such as fire regimes and species introductions, under different climate conditions/scenarios.
Finally, by focusing on islands in Ocean regions with little or no previous palaeoecological data, such as the Seychelles, in the Indian Ocean, we are filling critical gaps in our understanding of global biodiversity patterns and their changes over time
Goals
The TIME-LINES project aims to advance our understanding of biodiversity dynamics by analyzing long-term ecological changes and assessing the influence of geographical attributes and history on these changes at both taxonomic and functional levels on a global scale. By advancing the integration of palaeoecology with biogeography, TIME-LINES will unlock new research horizons, offering insights into the link between biodiversity and geography across millennia and contribute significantly to more effective conservation strategies in a rapidly changing world.
Global biodiversity is changing at an unprecedented rate, posing significant challenges for ecosystem stability and conservation efforts. Despite the urgency of this issue, our understanding of long-term biodiversity dynamics remains limited. The TIME-LINES project aims to investigate the dynamics of biodiversity change on islands globally over the past 5000 years, using them as model systems and biodiversity hotspots with varied human colonization times and impacts. This global approach will enable the development of palaeoecological networks spanning multiple biogeographical scales (islands, archipelagos, biogeographical regions, global).
Appraoch
Our lab has made a breakthrough in understanding biodiversity change by creating a detailed 'Plaeoecological Llibrary' that includes published records from islands around the world, making it a unique resource. Additionally, we employ a multi-proxy approach, integrating fossil pollen analysis with cutting-edge sedimentary DNA (sedaDNA) techniques. This combination allows for a more robust and detailed reconstruction of past ecosystems than either method alone. In addition, our analyses extend beyond biodiversity dynamics to include chronologies of key drivers of ecological change, such as fire regimes and species introductions, under different climate conditions/scenarios.
Finally, by focusing on islands in Ocean regions with little or no previous palaeoecological data, such as the Seychelles, in the Indian Ocean, we are filling critical gaps in our understanding of global biodiversity patterns and their changes over time
Goals
The TIME-LINES project aims to advance our understanding of biodiversity dynamics by analyzing long-term ecological changes and assessing the influence of geographical attributes and history on these changes at both taxonomic and functional levels on a global scale. By advancing the integration of palaeoecology with biogeography, TIME-LINES will unlock new research horizons, offering insights into the link between biodiversity and geography across millennia and contribute significantly to more effective conservation strategies in a rapidly changing world.
The TIME-LINES project has made advancements in understanding biodiversity dynamics through the following key activities:
1.Development of a Comprehensive Palaeoecological Library:
We have compiled an extensive library of all published fossil pollen and ancient sedimentary DNA (sedaDNA) records from islands worldwide. This unique resource forms the basis for our analyses, enhancing our understanding of long-term biodiversity patterns and enabling us to link biodiversity shifts with specific environmental and anthropogenic factors.
2. Analysis of new sedimentary sequences from islands:
We have conducted detailed analyses of new fossil pollen, charcoal, geochemistry, and sedimentary DNA (sedaDNA) from selected locations, including the Seychelles and La Gomera (Canary Islands), as well as samples from other sites. These new analyses will fill geographical gaps in our dataset.
3. Quantification of biodiversity trends:
First, we found that several Pacific islands are experiencing floral homogenization, meaning they are losing unique plant species and gaining more common ones. This demonstrates the impact of human settlement on island ecosystems (Strandberg et al., 2024). Our research also discovered a global rise in non-native plant species starting about 1,200 years ago, which could significantly impact island ecosystems and highlights the need for focused conservation efforts (Walentowitz et al., 2023).
1.Development of a Comprehensive Palaeoecological Library:
We have compiled an extensive library of all published fossil pollen and ancient sedimentary DNA (sedaDNA) records from islands worldwide. This unique resource forms the basis for our analyses, enhancing our understanding of long-term biodiversity patterns and enabling us to link biodiversity shifts with specific environmental and anthropogenic factors.
2. Analysis of new sedimentary sequences from islands:
We have conducted detailed analyses of new fossil pollen, charcoal, geochemistry, and sedimentary DNA (sedaDNA) from selected locations, including the Seychelles and La Gomera (Canary Islands), as well as samples from other sites. These new analyses will fill geographical gaps in our dataset.
3. Quantification of biodiversity trends:
First, we found that several Pacific islands are experiencing floral homogenization, meaning they are losing unique plant species and gaining more common ones. This demonstrates the impact of human settlement on island ecosystems (Strandberg et al., 2024). Our research also discovered a global rise in non-native plant species starting about 1,200 years ago, which could significantly impact island ecosystems and highlights the need for focused conservation efforts (Walentowitz et al., 2023).
While significant insights have been gained from palaeoecological data regarding biodiversity change trajectories, limitations exist in terms of temporal resolution and scale. Our newly developed datasets aim to overcome these limitations by providing enhanced global scaling and improved temporal resolution, simultaneously. We anticipate that the results will advance biodiversity change research, particularly in understanding the human dimension of biodiversity changes under the current antrhopogenic global change.