Biogeography, Conservation, and Genetics · Biogeography – the study of the distribution of life on Earth, or which organisms live where and why 2 primary components Historical

Biogeography, Conservation, and Genetics Biology of Fishes

11.13.12

Exam 2 information

Final Exam information

Presentations

Biogeography, Conservation, and Genetics

Overview

Guidelines online

All groups submit written reports 11.27.2012

Attendance required at all student presentations

Student Presentations material will be on Final Exam

Presentation Guidelines

November 15 – Conservation ecology case study synthesis

November 20 – Exam 2

November 22 – Thanksgiving Break

November 27 – Student Presentations

November 29 – Guest Lecture 3

December 4, 6, 11 – Student Presentations

December 19 – FINAL EXAM (Cumulative)

10:30am-12:30pm

Syllabus Revisions

Biogeography – the study of the distribution of life on Earth, or which organisms live where and why

2 primary components

Historical biogeography – influences on distribution over long temporal and large spatial scales

Ecological biogeography – influences on distribution based on interactions with environment over short temporal and small spatial scales

Foundation in continental drift and plate tectonics

Freshwater fishes provide some of the most important data

Biogeography

Historical Biogeography – why is a taxon restricted to a particular geographic area?

2 primary components/processes (consider together)

Vicariance – barrier appears and separates ancestral population into two groups, eventually separate taxa (barrier & taxa same age)

Dispersal – taxa develop from dispersal into new areas from ancestors that originally occurred elsewhere. Previously existing barrier is crossed by some individuals, eventually separate taxa (barrier older than taxa)

Biogeography

Historical Biogeography – why is a taxon restricted to a particular geographic area?

Vicariance

Dispersal

Biogeography

2 primary methods

Phylogeography – distribution of geneologies (gene lineages) within and among closely related species

Cladistic biogeography – based on cladistics (phylogenetics) to imply relationships which reflect geological and ecological history (area relationships inform general patterns among taxa)

Process (mechanisms) versus Pattern (distribution)

Biogeography

Biogeography of Fishes

~29,000 species

~60% marine, ~40% principally freshwater

Less than 1% are migratory between fresh & saltwater

Over 10,000 of 29,000 species occur in freshwater (0.01% of world’s water)

Marine environments not well-explored (deep-sea, second coelacanth)

Biogeography


Freshwater Regions (Hart & Reynolds 2000)

Nearctic (North America) 1060

Neotropical (South & Central America) 8000

Palaearctic (Europe, excluding former USSR) 360

Ethiopian (Africa) 2850

Oriental (Southeast Asia) 3000

Australian (Australia & New Guinea) 500

Biogeography


Biogeography


Marine Regions (Hart & Reynolds 2000; shore to 200 m)

Western North Atlantic 1200

Mediterranean 400

Tropical western Atlantic 1500

Eastern North Pacific 600

Tropical eastern Pacific 750

Tropical Indo-West Pacific 4000

Temperate Indo-Pacific 2100

Antarctica 200

Biogeography

Biogeography of Freshwater Fishes

Most freshwater fauna are poorly known (exceptions are North America and Europe)

Thorough survey work needed to inform historical biogeography; too late in most cases

Endemic fauna wiped out

Overexploitation, invasive species, habitat alteration

Focus on North American freshwater species

Mississippi River refugium and Wisconsinan Glaciation

Glaciated versus non-glaciated regions

Biogeography


Mississippi River refugium and Wisconsinan Glaciation

Biogeography


Glaciated versus non-glaciated regions

Biogeography

Biodiversity loss

Global crisis

Threatens all major habitats

Multiple geographical and ecological scales

Loss of local populations can have cascading effects

Disrupt ecosystem services

Relationship between biodiversity and ecosystem services is a function of local populations, not just existence of the species – conservation of populations is important

Conservation

Freshwater systems experience dramatic declines in biodiversity

Greater biodiversity loss than most terrestrial systems

Freshwater conservation priorities lag

Considered “sumps” and “receivers” of industrial & domestic wastes and land-use effluents

Exceptionally vulnerable to anthropogenic influence

Conservation

Freshwater systems experience dramatic declines in biodiversity

~3,600 of 10,250 known freshwater species (35%) are considered imperiled or threatened

~95-170 already extinct

Primary reasons are habitat alteration and exotic species invasions

95% of extinctions have occurred in past 50 years

Conservation

Identification of “stock” or population structure is a primary goal in genetics of fish populations

Multiple techniques – nuclear DNA, mitochondrial, microsatellites

Applications to fisheries management and conservation

Once lost, cannot be restored

Conservation Genetics

Multiple techniques (using PCR)

Nuclear DNA – evolves slowest, conservative; good for species studies

Mitochondrial DNA – evolves faster, maternally inherited; good intermediate for species and population studies

Microsatellites – repeating structures in nDNA; evolves fastest, high degree of population resolution


Conservation of genetic diversity is important for biodiversity and ecosystem function

Once lost, diversity cannot be restored

Poor knowledge of diversity partitioning within species or among populations – without appropriate knowledge, cannot assess conservation measures


Quantification of genetic population structuring is needed, particularly for threatened or vulnerable species

Structuring much more extensive for freshwater & anadromous species compared to marine species (endemics, salmonid stocks)


Prioritize stocks based on genetic and ecological consequences of extinction

Conservation efforts include habitat protection, reduction of harvest, stock enhancement (using same strain), translocation*

Determine minimum effective population size

High population size and diversity allows for some adaptive evolution and can reduce effects of inbreeding


Identification of “stock” or population structure is a primary goal in genetics of fish populations

Multiple techniques – nuclear DNA, mitochondrial, microsatellites

Applications to fisheries management and conservation

Once lost, cannot be restored


Important for management and conservation of both commercial and non-commercial species

Should be used in conjunction with other techniques – life history traits, morphological characteristics, microchemistry – for more complete picture of structuring

Careful husbandry of genetic resources is required (catalog, monitor, conserve)


Documents

Biogeography, Conservation, and Genetics · Biogeography – the study of the distribution of life on Earth, or which organisms live where and why 2 primary components Historical