Vocabulary:

• Reclamation: returning a piece of damaged or unused land to a more productive state. Notably, reclamation refers to measures taken to alleviate problems, even if it creates an ecosystem different from the original.
• Reintroduction: the deliberate release or translocation of a locally extinct / extirpated species, to parts of its original / natural range
• Restoration: returning a habitat, environment, or ecosystem to its original condition or membership, prior to a disturbance (often anthropogenic)
• Rewilding: conservation effort focused on restoring sustainable biodiversity and ecosystem health by connecting and preserving wild areas (that have not been significantly modified by human activity or used for agriculture), and protecting or reintroducing keystone species/apex predators.

Outline of Notes:

• General rules of context:
  • Diversity hotspots in hills and low mountains, resulting from speciation associated with different altitudes
  • Rock type/geologic history and landcover
  • Latitude and longitude affect patterns
• Different goals of restoration and reclamation:
  • Reclamation: prioritize increasing ecosystem functioning, not structure
  • Restoration: return ecosystem to its original state as much as possible

→ Ideal, but usually not realistic

• Rewilding: conservation effort focused on restoring sustainable biodiversity and ecosystem health by connecting and preserving wild areas, and protecting or reintroducing keystone species/apex predators.
  • Goals:
    • Slow/prevent extinctions
    • Restore ecosystem health
    • Minimize dependence on human intervention and management
      • Let nature take care of itself to restore damaged ecosystems

What Does the Future Look Like?

• Anthropogenic influences shape ecology
• Some species will thrive due to these anthropogenic influences
• These species share common characteristics

Blog-style Summary:

Global ecology encompasses the interactions of Earth’s ecosystems with the geosphere, hydrosphere, and atmosphere.

Global wind and water currents combine with global temperatures to drive the five major climate zones: tropical, dry / arid, temperate, continental, and polar. The relationship between temperature and moisture drives global patterns in terrestrial biomes through net primary productivity (NPP). Where the climate varies, elevation, geology and soil type can shift the balance between different biome types. Biomes, in turn, select for different traits, contributing to global biodiversity.

Global Challenges

Global challenges include events and processes that threaten large populations and many species across multiple continents. Global challenges often transcend national borders and require international cooperation for effective mitigation. Global challenges also increasingly impact global ecology.

Wildfires – predicting risk in a changing world

Wildfires pose a dual-threat to global ecology through habitat destruction and air pollution. Nearly 50% of ecoregions worldwide are characterized as having “very high” or “high” ecological vulnerability to fire (Figure 3), calculated based on post-fire regeneration delay and ecological indicators outlined in Table 1.

Wildfires require ignitions, continuous fuels, drought, and appropriate weather conditions. Ignitions increase the probability of a fire starting in the first place. Fuel continuity across the landscape increases the probability that a fire will spread, and drought increases the flammability of available fuels. Strong wind, high temperature, and low humidity contribute to “fire weather”, which collectively increases the probability of ignition, spread, and vegetation flammability. Climate change and increasing human populations drive changes in fuel loads associated with habitat fragmentation and fire exclusion – all of which further affects the main fire drivers.

In 2009, Krawchuck et al. modeled the observed global distribution of fires under current conditions (Figure 5). Then they predicted areas where fire would invade or retreat by 2039, if greenhouse gas emissions are emitted at mid-to-high levels (similar to climate models, but applied to estimate risk of wildfire). Keep in mind that fire invasion is caused by increased drought, ignitions, and fuel continuity (discussed in Figure 4, above). This means that fire is predicted to retreat in all the blue areas on Figure 6 (below) because habitat destruction and biodiversity loss will reduce the amount of available fuels.

In 2022, Harrison et al. predicted that tropical savanna and tropical deciduous broadleaf forest and woodland would be most affected by wildfires (Figure 7). Remember that trees and other vegetation contribute to Net Primary Productivity, meaning that wildfires will drive negative bottom-up control, with subsequent trophic cascades up the food webs in these habitats. In addition to decreasing energy resources (i.e., NPP), wildfires also reduce vertical structure (e.g., niche complexity), further reducing biodiversity.