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Conservation of Small Populations

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Small population sizes put a species at extreme risk of extinction due to a lack of variation, and a consequent decrease in adaptability. This weakens the chances of survival under pressures such as climate change, competition from other species, or new diseases. Large populations are more likely to survive pressures such as these, as such populations are more likely to harbor individuals that have genetic variants that are adaptive under new stresses. Small populations are much less...

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Related Experiment Video

Updated: Nov 8, 2025

Following the Dynamics of Structural Variants in Experimentally Evolved Populations

Following the Dynamics of Structural Variants in Experimentally Evolved Populations

Published on: February 3, 2023

Developmental instability and phenotypic evolution in a small and isolated bear population.

A Loy¹, P Ciucci², G Guidarelli¹

¹Envix Lab, Department of Biosciences and Territory, University of Molise, 86090 Pesche (IS), Italy.

Biology Letters

|April 20, 2021

Summary

This summary is machine-generated.

The Apennine bear (Ursus arctos marsicanus) exhibits high fluctuating asymmetry (FA), indicating developmental instability likely due to inbreeding depression. This unique divergence may offer evolutionary novelty for conservation efforts.

Keywords:

Ursus arctos marsicanus conservation fluctuating asymmetry inbreeding depression morphological integration small populations

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Area of Science:

Evolutionary biology
Conservation genetics
Morphometrics

Background:

The Apennine bear (Ursus arctos marsicanus) is a small, inbred, and divergent population facing unique evolutionary pressures.
Understanding developmental instability and morphological integration is crucial for assessing the health of isolated populations.

Purpose of the Study:

To investigate fluctuating asymmetry (FA) and morphological integration (MI) in the Apennine bear skull.
To assess potential effects of inbreeding depression on Apennine bear development.
To compare Apennine bears with outbred populations to understand their uniqueness.

Main Methods:

Utilized 3D geometric morphometrics on skull landmarks.
Employed principal component analysis (PCA) for shape divergence and variability.
Applied Procrustes ANOVA, morphological disparity, and global integration index to analyze FA and MI.

Main Results:

Apennine bears displayed the highest FA and deviation from self-similarity compared to Scandinavian and Kamchatka bear populations.
A highly divergent phenotype was observed in the Apennine bear.
Trait covariance patterns were distinct in the Apennine bear population.

Conclusions:

Apennine bears likely experience developmental instability, potentially linked to inbreeding depression.
The observed divergent trait covariance may represent a source of evolutionary novelty.
Findings have implications for the conservation and management of this endangered taxon.