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Terrestrial ecosystems & ecology - Coggle Diagram
Terrestrial ecosystems & ecology
Arctic flora comprises about 2200 species of vcascular plants
Endeminism is very scarse in the arctic
This represents less than 1 % of the global vascular plant species, indicating reletively low diversity
Millions of years ago, rainforests covered both poles
The pliocene-Quaternary glaciation is a series of many glacial cycleys, possibly 18, during the last 2.5 million years.
Ancestors of the arctic flora
the early pleistocene arctic flora is hypothesized to have originated from a combination of tertiary forests elements and ancestral stocksd from temperate high mountain ranger in Asia and North America
Paleoecology and deep coring techiques
LGM = last glacial maximum
Post-glacial migration
Evolve out of trouble
Move out of trouble
become migration
Climate change refugia
In situ refugia
Ex situ refugia
Locations where taxa survice periods of regionally adverse climate, critical for maintaining biodiversity through the glacial-interglacial climate changes of the Quaternary
Main refugia
Proximal refugia
distal refugia
Diffuse refugia
The extent of this biodiversity loss varied. The timing and extent of the LGM ice sheets varied across regions, incluencing the dynamics of extinction/colonization, and ultimately shaping the picture of both species- and genetic diversiity we see today.
THe LGM extent stopped to north-east russia/siberia because the area is very dry.
Recolonization and the loss of genetic diversity.
species usually lose genetic diversity during migrations
Leading edge colonization: Re-colonization of several species.
Following the LGM, species migrated from refugia land to newly available habitats, shaping present-day arctic biodiversity.
Regions with large refugia and continuous land connections to boreal areas exhibit higher species richness today
Genetic diversity within species is higher in areas that were recolonized from multiple refugia, reflecting complex migration histories
Environmental factors shaping
Environmental heterogenity
Pan-Arctic scale: bioclimatic subzones
The arctic region is categorized into five different. Each
Latitude and elevation are key indicators
Local scale: Habitats and microhabitats, high spatial heterogenity
Snowbeds
Microclimate
Soil conditions
Physioligical adaptation
High tolerance to low temperatures and the ability to photosynthesize at low light levels are common. Some plants can endure anoxic soil conditions resulting from water saturation
Most ccommonly these patches are dominated by bryophytes
Variations in elevation and landscape features affect snow accumulation and melt patterns, leading to diverse microhabitats.
Small topographic gradients generate microhabitats such as dry exposed ridges
braided riverplans
Succession gradients in the arctic tundra
In the arctic, pioneer plants take decades to colonize. The first organisms to establish in front of retreating glaciers are lichens, mosses and cyanobacteria.
Environmental heterogenity refers to the variability and complexity of environmental conditions across spatial and temporal scales, driven by factor such as climate, topography, snow cover, soil characteristics, and vegetation
To understand which environmental factors are decisive to the species composition in an area, we need to combine information that vary at different spatial and temporal scales
Vascular plants
Dominant life-forms
Forbs and graminoids
Diversity, and characteristics
Dwarf shrubs
Cold resistance
Short growing season
Wind and frost protection
Nutrient efficiency
arctic plant habitats
The circumpolar arctic vegetation map (CAVM) is a comprehensive map that classifies arctic vegetation into 16 vegetation types across the entire arctic region. It provides a standardized framework for studying arctic ecosystems and their responses to environmental change.
Adaptations for arctic conditions
Low temperatures slow metabolism
Low light
poor nutrients
Limited precipitation
Summer adaptations for arctic conditions: Frost, photosynthesis, and reproduction
Drought, Anoxia and Recourse scarcity
Water conservation and root systems
Anoxia tolerance
Nutrient retention and recycling
Extensive root systems
Reproductive adaptations to seasonality
Metabolic and photosynthetic efficiency: arctic plants compensate for slow metabolic processes with a higher number of mitochondria and increased oxidative capacity per mitochondrion
Extremely short arctic growing season
Winter adaptations for arctic conditions
Cold hardening
Morphological strategies
Role of snow cover
Buds in plants are undeveloped or embryonic structures that have the potential to grow into new shoots, leaves, flowers, or stems
Adaptations of bryophytes
Exhibit remarkable resilience in arctic environmental due to several key adaptations
local spatial heterogenity
Bryophytes are ancient, non-vascular land plants that include mosses, liverworts and hornworts. They are among the earliest plants to colonize land, originating around 470-515 million years ago
Phenotypic plasticity
Prevalence of moist habitats
Ecosystem role of bryophytes (I)
Regulation of hydrology
Temperature regulation
Contribtuon to vegetation productivity
Carbon storage
Nitrogen fixation
food source
Habitat for invertebrates
defoliation outbreak
Mechanisms of herbivory
Grazing
Browsing
Trampling
Clipping
How to quantify herbivore diversity
Poop collection
Grazing exclusion
Repeated vegetation surveys
COAT experiment in Varanger, Norway
Species distribution models: Hindcasting past distributions
Impacts of herbivory on ecosystems