Biogeography, Conservation, and Genetics Biology of Fishes 11.13.12
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Transcript of Biogeography, Conservation, and Genetics Biology of Fishes 11.13.12
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