Biogeography, Conservation, and GeneticsBiology 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

Biogeography of Fishes 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 of Fishes

Biogeography

Biogeography of Fishes 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

Focus on North American freshwater species Mississippi River refugium and Wisconsinan Glaciation

Biogeography

Focus on North American freshwater species 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 Genetics

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

Conservation Genetics

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)

Conservation Genetics

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

Conservation Genetics

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

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)

Conservation Genetics