1 / 53

Birds & Conservation

Birds & Conservation. A Global & Local Perspective. Major Conservation Issues. Humans Habitat Toxic compounds Exotic species Island Effect Nest Parasites. General Effects of Humans: we take up space & demand resources. Human population & associated effects Huge size (~ 6 billion)

galya
Télécharger la présentation

Birds & Conservation

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Birds & Conservation A Global & Local Perspective

  2. Major Conservation Issues • Humans • Habitat • Toxic compounds • Exotic species • Island Effect • Nest Parasites

  3. General Effects of Humans:we take up space & demand resources • Human population & associated effects • Huge size (~ 6 billion) • Future increases in population - some models suggest peaks @ between 12-20 billion • Development (all ↓ available habitat) • Housing • Industry • Agricultural

  4. Human Presence

  5. Other Associated Human Effects • Excessive Hunting • when going beyond sustainable levels • turn of century feather collectors • poaching of endangered species • Examples: • Passenger Pigeon • Great Auk • Eskimo Curlew & other shorebirds

  6. Once the most abundant bird in North America, the Passenger Pigeon is now extinct. Overhunting for markets is though to be one contributing factor.

  7. Formerly a common spring migrant in in eastern SD; now probably extinct Eskimo Curlew Texas 1962

  8. Upcoming Schedule • Final Field Trip – Sat., May 1 • Newton Hills State Park • 0730-1400 • Final Exam • Thursday, May 6 • 1230 to 1430 • Will cover material since second exam (Social Systems through Conservation)

  9. Other Associated Human Effects…… • Road Kills • Cats • Collisions • buildings, windows, communications towers • Human activities directly kill an estimated 1 billion birds each year in the U.S.

  10. Avian Collision Study (Erickson et al.2005)Annual estimates of U.S. Mortality • Vehicles (80 million) • Buildings/Windows (100 million-1 billion) • Powerlines (130 million) • Communication Towers (4-5 million) • Wind Turbines (20-40 thousand) • For comparison: house cats = about 100 million annually in N. America • Total anthropogenic mortality = > 1 billion

  11. Habitat Destruction • Loss • destroyed altogether • removal and replacement with human-altered habitat • Fragmentation • partial destruction as well as separation of once-connected areas into isolated fragments • leads to lower total area & possible separation of populations in fragments

  12. Habitat Destruction…… • Degradation • lower quality due to a variety of factors such as exotic species, increased edge, toxins, etc. • cheatgrass or other weeds • agricultural runoff in a stream

  13. Many habitats are threatened • Tropical Rainforests • Temperate Forests • Wetlands/Riparian Areas • Grasslands • With loss of habitat, there is less area to sustain populations

  14. New World Rainforest p. 642 Gray: extant forest Black: destroyed

  15. SE Asian Rainforest p. 642 Gray: extant forest Black: destroyed

  16. Examples • Golden-cheeked Warbler • breeds central Texas • winters S Mexico • housing developments, recreation, etc. • cowbirds • Riparian birds in South Dakota • many woodland habitats now gone due to dams and conversion to agriculture • limited habitat area for populations

  17. Note dramatic decreases in forest and grassland habitats

  18. Migratory Birds • Need suitable habitat for all phases of life cycle: • breeding, wintering, migration • Habitats migrants use often differs among seasons • Conservation plans must be complex to safeguard all important habitats

  19. Habitat Conservation Efforts • Preserves: • National Parks, National Wildlife Refuges, National Forests & Grasslands, state & local parks, private • Conservation easements: • private land set aside, CRP • Endangered Species Act: • mandates protection for species threatened by human activities • Need ecosystem-based approaches

  20. Environmental toxins • Pesticides • DDT • PCB’s • Fertilizers • Fossil Fuels • Household Chemicals

  21. Pesticides • Widespread use: • household & lawns • agricultural • pest control • Many effects • reduce prey populations • non-target mortalities • For example, Birds of Prey • bio-accumulation and bio-magnification

  22. Example of Pesticide Effects: DDT • DDT: 1,1,1-trichloro-2,2-bis-(p-chlorophenyl) ethane • widespread use mid-1900s • population declines noticed in many birds, especially predators • Osprey, Bald Eagle, Peregrine Falcon • Peregrine almost extinct in eastern US • DDT banned in US in 1972 • subsequent rebound of all raptor species affected

  23. Bald Eagles before & after DDT ban: Reproduction & amounts of DDE p. 565

  24. Local Toxin Example: Selenium & colonial waterbirds • Selenium (Se): • trace mineral • important in small amounts • key component of enzymes

  25. Selenium & colonial waterbirds • The problem: • high concentrations of Se found in some soil types: (e.g., marine shale) • Se leaches from soil in high amounts • agricultural run-off leads to high [ ] in bodies of water • Se will bioaccumulate (increasing levels as you move up food chain)

  26. Selenium & colonial waterbirds • Effects on birds: • deformities • reduced reproductive success • Rookery @ Stratford Slough (Brown Co., SD) • ~ 1000 birds ‘destroyed’ due to selenium

  27. Exotic Species

  28. Exotic Species • Exotic Introduced Non-native • any species living outside of its natural range • Sources: • human colonists (“acclimatization societies”) • agriculture • accidental transport • biological control • ‘just for fun’

  29. Examples of Exotic Species • southern US: Fire Ants • Guam: Brown Tree Snake • US: European Starling • House Sparrow • Rock Pigeon • Ring-necked Pheasants • Hawaii: > 50 introduced bird species

  30. Why are exotics a problem? • Freedom from usual population limitation • no natural predators • no usual diseases • Competition with or predation of native species: • native species may have not evolved defenses or necessary behaviors to ‘deal with’ exotics

  31. Effects of FireAnts: predation competition

  32. Brown Tree Snake in Guam Bird

  33. Exotic Birds • European Starling: • introduced to Central Park in NYC ~ 1890 • now most common bird in US • competes for food & nest cavities • House Sparrow & Rock Pigeon • more confined to human areas • still compete w/ natives • House Sparrow vs. Purple Martin

  34. More Exotic Birds • Ring-necked Pheasant & other game birds (Chukar, Gray Partridge, etc.) • favored for hunting • may compete w/ native grouse (???)

  35. Birds and Islands

  36. Island Biogeography • ‘The small island effect’ • Small islands support small populations • Island populations often not exposed to full range of ecological factors • predators • pathogens

  37. Island Biogeography…… • Evolve unique adaptations, which often lead to speciation • flightlessness • ground-nesting • More sensitive to changes in environment • Hawaii • Guam • fragmented habitats

  38. Hawaii • Isolated volcanic islands • populated by founder species that colonized • adaptive radiation • many unique, locally adapted species • flightless Ibis & honeycreepers • few predators

  39. Hawaii…… Human effects over last 2 millenia: • introduced pigs & other ungulates • over-grazing/browsing • introduced rats (nocturnal) • predators of many unsuspecting birds • introduced mongoose (diurnal) • preys on many birds (not rats!) • introduced mosquitoes • avian malaria w/ introduced birds • spread by mosquitoes

  40. Hawaii…… • ~ 1/2 of original species remain • many remaining are threatened by habitat loss, diseases, & vagaries of small population size

  41. Guam • Brown Tree Snake • elimination of all wild populations of Guam’s endemic birds: • rail, kingfisher, songbirds, etc.

  42. Island Biogeography & Mainland Ecosystems • Naturally occurring ‘islands of habitat’: • Black Hills • ‘Sky Islands’ of desert southwest • Human-caused fragmentation: • once extensive areas now only patches • forest • grassland • etc.

  43. Cowbirds and Conservation • Brood parasitism has negative impacts on host reproductive success • Cowbirds feed in open areas but parasitize many forest-dwelling songbirds • Human activities have allowed cowbirds to expand their range • Forest fragmentation  more open areas • Cattle ranching  associate with bison/cattle

  44. Cowbirds and Conservation • Brown-headed Cowbirds have parasitized over 220 species • Of these < 25 eject cowbird eggs, 37 desert nest to renest, only a few build a new floor over clutch. Most are susceptible. • Parasitism probably not responsible for continent-wide population declines, but do impact some endangered species. • Least Bell’s Vireo, Kirtland’s Warbler, Black-capped Vireo, SW Willow Flycatcher)

  45. Cowbirds and Conservation • Control Issues: • Some view killing cowbirds as inhumane • Cowbird removal is only a short-term solution to the problem • Cowbird removal is expensive • Bell’s Vireo: over $665K/year (225 traps/yr, each trap gets about 3,000 cowbirds/yr) • Kirtland’s Warbler: $90K/yr • Black-capped Vireo: $45K/yr • Removal doesn’t increase population size for all species

More Related