CourseCourseQ BankQuestion BankDocsDocuments

D4.3.6—Range shifts

Climate-driven range shifts occur when species move poleward, upslope, or into new habitats as temperature, water, and resources change over time.

Syllabus
First assessment 2025
Objective
D4.3.6
Level
HL

Exam analysis

Chance of appearing1%of analysed past papers
Latest appearanceMay 2024
Most common paperPaper3
Typical marks1

Common command terms

  • Explain
  • Compare
  • Discuss
  • Suggest

Recent exam appearances

May 2024Paper3 ["HL"] · TZ116(b)[ 1 ]D4.3.6—Range shifts
Practice this objective

Coverage 2024–2024 · Updated 16 Jul 2026

Climate Suitability Shifts Ranges Upslope and Poleward

As temperature zones move, species may shift upslope or poleward if dispersal and suitable connected habitat allow them to track their climatic niche.

Evidence case Observed pattern in mapped local textbook
Montane birds, Papua New Guinea Upper range limits shifted upslope by 113 m on Mt Karimui and 152 m on Karkar Island compared with 1960s records
Eastern North American trees Many species showed range contraction or northward spread; Quebec sapling shifts were faster than adult-tree shifts

High-elevation species can run out of cooler habitat, while slow-growing trees may not disperse fast enough to match the speed of climate change.

A shifting observation is not automatically caused only by climate; land use, barriers, competition and survey effort must also be assessed.

Range shifts

Assessment in practice

1–2 marks
How it is assessed

This objective is assessed through multiple choice, structured response, commonly using Explain / Compare / Discuss.

Command terms

Explain / Compare / Discuss / Suggest

What earns marks

Build the answer around this relationship: Warming can move suitable climate zones and food supplies northward or upslope.

Representative question

Question 1

[Maximum number: 1]

The data shows how the hardiness zones in part of North America are predicted to change over the next 25 years. A hardiness zone is an area that has a certain average annual minimum temperature, a factor relevant to the survival of many plants. The lower the number, the more cold

resistant the plants must be.

What is a likely consequence of this change for tree species?

A

Tree species will spread northwards as climate changes.

B

Tree species that are not cold-resistant will decline.

C

There will be no change in the distribution of the tree species.

D

Tree species that currently live in the north will outcompete other tree species.

Retrieve the SL Climate Chain

Core D4.3 is secure when every climate impact is explained as a chain: human greenhouse-gas sources or feedbacks change climate conditions, which alter habitats, oceans, carbon stores, or species distributions. Carbon sequestration is the mitigation chain that stores atmospheric CO2.

  • human gases and positive feedbacks amplify warming
  • boreal forests, ice habitats, upwelling and reefs shift through specific mechanisms
  • species may move poleward, upslope, contract, or lose ice/reef habitat
  • afforestation, agroforestry, regeneration and peatland rewetting store CO2

Climate Effects on Ecosystems

Core climate-change transfer answers should not list endangered examples. They should identify the climate driver, explain the physical or chemical mechanism, then state the biological consequence. Use this for greenhouse gases, feedbacks, boreal forests, ice-dependent species, upwelling, range shifts, reefs, and carbon sequestration.

  • Link human activities to increased greenhouse gases and enhanced warming.
  • Explain ecosystem impacts using mechanisms such as positive feedback, carbon sink/source shifts, habitat ice loss, reduced upwelling, range shifts, bleaching or acidification.
  • Explain carbon sequestration by naming the storage pathway in biomass, forests, soils or peatlands.

Concept essentials

  • Warming can move suitable climate zones and food supplies northward or upslope.
  • Range shifts can change predation, competition, biodiversity, and food-web structure.
  • Species that cannot track suitable conditions may decline or disappear from parts of their range.