Lumping and Splitting of Distribution Models Across a Biogeographic Divide Informs the Conservation of an Imperiled...

Area of Science:

• Ecology
• Conservation Biology
• Ichthyology

Background:

• Freshwater fishes are highly threatened globally.
• Limited life history and habitat data hinder conservation of declining species.
• Species distribution models (SDMs) are valuable tools for assessing distribution patterns and conservation needs.

Purpose of the Study:

• To understand large-scale distribution patterns of the Bluntface Shiner (Cyprinella camura; BFS).
• To identify landscape-scale abiotic factors influencing BFS distribution.
• To compare environmental conditions between BFS populations east and west of the Mississippi River and assess model transferability.

Main Methods:

• Utilized species distribution models (SDMs) incorporating occurrence records and geospatial data.
• Modeled potential BFS distribution based on abiotic factors.
• Compared environmental niches across the Mississippi River biogeographic divide and tested model transferability.

Main Results:

• Identified naturally fragmented distribution patterns for BFS east and west of the Mississippi River.
• BFS populations east of the Mississippi River occupy streams with distinct broadscale environmental conditions compared to western populations.
• SDMs projected across the Mississippi River did not accurately reflect contemporary BFS ranges, indicating differing occupied niches.

Conclusions:

• The study provides a baseline for assessing range loss in Bluntface Shiner.
• Identified areas of high habitat suitability for targeted conservation efforts.
• Highlights the need for caution when projecting SDMs across biogeographic barriers due to niche divergence.