Lecture 4a: species level climate change impacts: population Flashcards
Anthropogenic climate change extinctions as a result of population declines
Population definition:
Definition: “A group of interbreeding individuals found within a given area at a given time”
What are the limits of breeding and how to prove? how can you prove all individuals can interbreed?
How big of an area?
Population is difficult to define for example;
e.g. The population of lion has decreased from the red area to just the orange areas
^ Are they now multiple populations or are they migrating between areas (I.e. a metapop.)
e.g. Populations of swallow? Northern and southern or defined by continent – or due to migration just one large population?
The size of the area covered by a population is dependent on the taxa and the question of interest
– Breeding largely assumed in continuous areas of distribution
– Smallest area with unique population data (ideally little immigration or
emigration)
How do we monitor populations?
Line transects and distance sampling
Mark and recapture
Tagging (mobile animals – but also trees – most suited to long-lived species)
Quadratting (plant/ insects)
Camera traps
Walking transects (small animals and bird observations) / driving them (large mammals)
Surveys from hides – most effective at water sources for large mammals or wetlands/reedbeds for bird observation
Coastlines are also a good place to observe wader species and seals – ideally a clear view of a specific area
Water, air and soil samples are also indicative
Remote sensing approaches are increasing in use for higher accuracy and larger quantity of data capture
Describing a species niche
see diagram in notes for 1 and 2 dimensions
Direct impacts of climate on demography
example:
level of rainfall correlates with survival chance in Scottish sheep species (Catchpole et al 2022)
Species interactions: Biomes
biomes are defined by plant species which relate to rainfall and climate
see world map in biomes in notes
Indirect impacts of climate on demography
example: Loison et al 1999
greater snowfall = lower body mass due to reduced grazing ability
Less snowfall could increase pop. An issue in areas where red deer are invasive and potentially beneficial in native areas
Drivers of avian occurrence and abundance
- Hierarchical scheme of environmental controls
- Distinguish finer scale variations in habitat quality
Species traits and interactions
from Franklin 1995, Thuiller et al. 2004, Howard et al. 2014
in order of impact:
*Climate
*Geology
*Land Use
*Topography
^ all contribute to species distribution and abundance
Climate change drives abundance changes
see schematic graph in notes:
Schematic representation of species’ responses to climatic changes. Species’ predominant response to climatic changes depends upon the combination of the magnitude and the rate of those changes. Spatial responses, i.e. changes in geographical distribution, predominate for relatively large magnitude and relatively rapid changes, such as those projected for the present century.
also see Ehrlich et al (1980) study of checkerspot butterfly - habitat central area went through drought and saw pop. Decline
& also Ozgul et al. (2010) study of yellow bellied marmots - gradual climate change has allowed the marmots to come out of hibernation earlier, feed more raise more offspring successfully and better survive hibernation the following winter
Abundance responses
see: Parmesan, C. & Yohe, G., 2003. A globally coherent fingerprint of climate change impacts across natural systems. Nature, 421(6918), pp.37–42.
^ Abundance/distribution records for >600 species over time periods of 17 – 137 years
* Woody plants, herbaceous plants, shrubs
* Lichens
* Birds, mammals, reptiles and amphibians
* Insects
* Fish
* Marine invertebrates
* Marine zooplankton
National and supranational indices
macroecological study is taking over from localised studies
e.g North American Breeding Bird Survey
& Pan European Common Bird Monitoring
Scheme -PECBMS
Funding is v. limited so this is more efficient for NGOs
Birds and butterflies are well researched but all other taxa require greater coverage
Species distribution models
correlate area of distribution with climate variations to come up with predictions for future population conditions (I.e. how suitability of climate changes to favour/disfavour pop. Growth)
Climate indicator indices
See Stephens et al (2016) and Gregory et al (2009) graphs in notes
Positive identification of climate change as a population influencer
Range boundaries
See Parmesan et al 1999
& Freeman et al 2018
^ edges of range see pop decline on southern and increase on northern edge according to moving towards the north pole and the alternate in the southern hemisphere again moving away from the heat of the equator
Higher altitudes are becoming colonised by species previously observed at lower alt.
Summary
Summary
- Populations are typically defined dependent on the data available
– Studies of localised populations give more accurate representation of impacts of climate change
– More coarse/widespread study less susceptible to impact by other factors and more useful to policymakers/practitioners - Method of monitoring dependent on taxa
– Citizen science/national/supranational monitoring schemes provide long-term abundance data across large geographical areas
– Data lacking from the vast majority of taxa – birds and butterflies probably the best studied - Climate can impact demography directly through physiological
processes or indirectly through species interactions - If individuals are unable to respond to climate change behaviourally to stay within their ecological niche:
– Survival and productivity will decline
– Populations decline - Impacts largely negative but warm adapted species may prosper
