Abstract:
Climate change and managing ecosystems to mitigate climate change both have profound implications for the future of biodiversity. In this talk, we will present large scale experimental manipulations, mathematical models of community change, and statistical analysis of large data sets to answer various questions at the intersection of climate and biodiversity. First, we will present an altitudinal transplant experiment with alpine plant communities to show that novel competitive interactions shape species’ responses to climate change. Second, we will present the predictions of mathematical models informed by field data to show how demographic and competitive time lags govern the pace of community change in this system. Last, we will use an analysis of large data sets to show that different land-based climate mitigation strategies- forestation and bioenergy- have vastly different effects on global biodiversity, effects that are dominated by habitat conversion. Together this work shows how multiple ecological approaches must coalesce to address the climate and biodiversity crises.
Bios:
Jonathan Levine: Jonathan received his PhD in 2001 from UC Berkeley, was a postdoctoral researcher at Imperial College, an Assistant Professor at UCLA, moved to UC Santa Barbara in 2003, and was appointed Professor of Plant Ecology at ETH Zurich in 2011 before moving to Princeton University in 2019, where his research emphasizes species coexistence, plant migration and invasion, and community responses to climate change.
Jeffrey Smith: Jeffrey is an Associate Research Scholar with the Princeton High Meadows Environmental Institute. His research broadly focuses on the processes that structure present-day patterns of biodiversity and how climate change and land-use intensification are likely to affect biodiversity in the future. Specifically, his current work focuses on understanding the potential impacts of land-based climate change mitigation strategies such as reforestation, bioenergy cropping, and the build-out of renewable energy technology, will affect biodiversity both by changing land-use patterns and helping mitigate climate change. Prior to his time at Princeton, Jeffrey obtained his PhD at Stanford University and a Masters of Environmental Science from the Yale School of the Environment.
Summary:
Focus:
Impact of climate change on the distribution of species
Impact of species migration on regional eco-dynamics and biodiversity
Key idea:
Each species has a preferred band of environments: habitats, temperatures, etc.
Environments move in space due to climate change; different speeds for various environments and species
This causes new species to come into contact with each other
Focus area: Alpine environments
Interesting because changes in elevation have a big impact on change in a short horizontal distance
Warming climate causes more temperate species to move to higher elevations
Observing low-land plants coming into contact with highland plants
Approach:
Take plants that are expected to move close to each other, move them together
Move high-land plants to warmer climates in lower elevations: take a layer of soil with all the grass and flowers and move it
Experimental results show that moved plants survive worse in their new community
Question: how long does the impact of climate change on plant communities take?
Study area:
Calanda mountain, Switzerland
Elevation 1000m-2000m, 5°C difference
Track test plots of plants growing over time
2D photos that document individual plants and their size
Observe death, growth, recruitment (new plant) events across all species
Train a statistical model of these 3 processes for each species conditional on interactions with other species, temperature
Given this model, can forecast evolution of plant communities under different climate conditions
Century-scale forecasts of plant community evolution
Forecast of whole-habitat diversity projections
Insects create a faster dynamic since they move much faster than plants
When they move to a warming area they are able to attach plant species that no defense against them
Analyzing this interaction is ongoing work
Modeling interaction between climate change and plant communities and the animals that live with them?
Novel competitive interactions -> species
Impact of land-based climate mitigation
Carbon removal via tech (direct air capture) or nature (reforestation)
Focus: impact of nature-based carbon removal on ecosystems
Forest management/reforestation
Bioenergy with Carbon Capture and Storage, Biochar
Soil Carbon
Enhanced Chemical Weathering
Nature-based carbon removal (Reforestation, afforestation, bioenergy cropping) affects ecosystems
Land Based Mitigation Strategy (LBMS) -> Habitat conversion -> Biodiversity
Approach:
LBMS -> changing local environment
Use MaxEnt species distribution models to predict changing range of species (e.g. moose) under various climate scenarios
Using downscaled climate model predictions under various emission and carbon removal scenarios
Use of LBMS modifies regional habitats (more forest, more grassland, etc.)
Use MaxEnt to predict how the modification affects the range of different species
E.g. adding forest is good for moose, bad for field mice.
Combination of changing LBMS impacts and change in global mean temperature affects species in complex ways
Predicting impact of afforestation/reforestation on habitat
Africa, Cerrado in Brazil: reduction in habitat area
North America, South America, Europe, China: increase in habitats
i.e. adding trees to historically forested biomes increases biodiversity
Intuition: lions or other savanna species will be harmed by forests
Effect via climate stabilization is smaller but consistently positive
Prediction impact of bioenergy crops on habitats
Generally worse for habitats, especially for historically forested regions
India and China: improved biodiversity
Effect via climate stabilization is larger than for forests and also consistently positive
Produced regional recommendations for which technique (trees or bioenergy crops) to prefer when optimizing for biodiversity
In many cases its better to leave the current ecosystem intact