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Two wolves survive in worlds longest running predatorprey study

first_img By Christine MlotApr. 18, 2017 , 8:00 AM Isle Royale’s two remaining wolves aren’t likely to breed, given their close relatedness and the female’s aggressive display.  Two wolves survive in world’s longest running predator-prey study Sign up for our daily newsletter Get more great content like this delivered right to you! Country Click to view the privacy policy. Required fields are indicated by an asterisk (*) Rolf O. Peterson center_img Country * Afghanistan Aland Islands Albania Algeria Andorra Angola Anguilla Antarctica Antigua and Barbuda Argentina Armenia Aruba Australia Austria Azerbaijan Bahamas Bahrain Bangladesh Barbados Belarus Belgium Belize Benin Bermuda Bhutan Bolivia, Plurinational State of Bonaire, Sint Eustatius and Saba Bosnia and Herzegovina Botswana Bouvet Island Brazil British Indian Ocean Territory Brunei Darussalam Bulgaria Burkina Faso Burundi Cambodia Cameroon Canada Cape Verde Cayman Islands Central African Republic Chad Chile China Christmas Island Cocos (Keeling) Islands Colombia Comoros Congo Congo, the Democratic Republic of the Cook Islands Costa Rica Cote d’Ivoire Croatia Cuba Curaçao Cyprus Czech Republic Denmark Djibouti Dominica Dominican Republic Ecuador Egypt El Salvador Equatorial Guinea Eritrea Estonia Ethiopia Falkland Islands (Malvinas) Faroe Islands Fiji Finland France French Guiana French Polynesia French Southern Territories Gabon Gambia Georgia Germany Ghana Gibraltar Greece Greenland Grenada Guadeloupe Guatemala Guernsey Guinea Guinea-Bissau Guyana Haiti Heard Island and McDonald Islands Holy See (Vatican City State) Honduras Hungary Iceland India Indonesia Iran, Islamic Republic of Iraq Ireland Isle of Man Israel Italy Jamaica Japan Jersey Jordan Kazakhstan Kenya Kiribati Korea, Democratic People’s Republic of Korea, Republic of Kuwait Kyrgyzstan Lao People’s Democratic Republic Latvia Lebanon Lesotho Liberia Libyan Arab Jamahiriya Liechtenstein Lithuania Luxembourg Macao Macedonia, the former Yugoslav Republic of Madagascar Malawi Malaysia Maldives Mali Malta Martinique Mauritania Mauritius Mayotte Mexico Moldova, Republic of Monaco Mongolia Montenegro Montserrat Morocco Mozambique Myanmar Namibia Nauru Nepal Netherlands New Caledonia New Zealand Nicaragua Niger Nigeria Niue Norfolk Island Norway Oman Pakistan Palestine Panama Papua New Guinea Paraguay Peru Philippines Pitcairn Poland Portugal Qatar Reunion Romania Russian Federation Rwanda Saint Barthélemy Saint Helena, Ascension and Tristan da Cunha Saint Kitts and Nevis Saint Lucia Saint Martin (French part) Saint Pierre and Miquelon Saint Vincent and the Grenadines Samoa San Marino Sao Tome and Principe Saudi Arabia Senegal Serbia Seychelles Sierra Leone Singapore Sint Maarten (Dutch part) Slovakia Slovenia Solomon Islands Somalia South Africa South Georgia and the South Sandwich Islands South Sudan Spain Sri Lanka Sudan Suriname Svalbard and Jan Mayen Swaziland Sweden Switzerland Syrian Arab Republic Taiwan Tajikistan Tanzania, United Republic of Thailand Timor-Leste Togo Tokelau Tonga Trinidad and Tobago Tunisia Turkey Turkmenistan Turks and Caicos Islands Tuvalu Uganda Ukraine United Arab Emirates United Kingdom United States Uruguay Uzbekistan Vanuatu Venezuela, Bolivarian Republic of Vietnam Virgin Islands, British Wallis and Futuna Western Sahara Yemen Zambia Zimbabwe Email The researchers also observed that, in what normally would have been the wolves’ breeding period, the 7-year-old female bared her teeth in response to the close interest of the 9-year-old male; he is both her father and half sibling.  Researchers don’t expect the highly inbred pair to reproduce.The two wolves otherwise appeared healthy and still have all their canines, a key sign of well-being in the carnivores. The pair has already surpassed the average Isle Royale wolf lifespan of 4 years, dodging the main causes of death for their ancestors on the island: other wolves and starvation. “They are swimming in moose,” Vucetich says.The four wolf-killed carcasses the researchers spotted made little dent in the overall moose population, estimated at 1600 in aerial surveys conducted this past winter.  The 20% increase from last winter is consistent with the population’s growth rate over the past 6 years, as the inbred wolf population dwindled and collapsed.  Both beaver and moose abundance have tripled since 2011, “undoubtedly because of lack of predation,” Vucetich says.With moose density on the Guam-sized island already five to ten times higher than on the mainland–and with the numbers on track to double in three to four years—browsing on the island’s vegetation is intense. One aquatic plant, floating watershield (Brassenia  schreberi), which was abundant six years ago when moose were at historic lows, now thrives in ponds only where moose are excluded. “It’s the aquatic equivalent of deforestation,” says plant ecologist Eric Hellquist of SUNY Oswego, noting that moose’s effect on aquatic vegetation is not as well studied as that on terrestrial plants. Isle Royale’s ponds are demonstrating “how apex predators can have cascading effects on food webs.” As the effects of the missing predators ripple through the island, the Park Service is assessing about 5000 public comments on its proposal to introduce 20 to 30 wolves to the island to establish a new population. The next steps on that plan are expected by the end of this year. For 2 years in a row, a pair of wolves has managed to survive on Isle Royale, Michigan, the last of their kind on the wilderness island. Researchers continue to track the wolves and their moose prey, in the last installments of the world’s longest running predator-prey study.  They report today that although the wolves hunt successfully, they are too few to affect the moose population. Aquatic as well as terrestrial vegetation is taking a hit as moose numbers climb, according to the study’s 59th annual report.After Canadian wolves colonized the island in 1949, the wolf population peaked at 50 in 1980, and as recently as a decade ago, 30 wolves prowled the island, a U.S. National Park. The island’s now-famous predator-prey study has tracked how wolf and moose numbers have risen and fallen in tandem over the decades, and left their mark on the island’s ecology. In contrast to last year’s winter study, when wolf tracks were the only evidence of the predators, wildlife ecologist Rolf Peterson spotted both wolves sitting on lake ice on the January afternoon he arrived on the island.  Weeks later, Peterson and co-investigator John Vucetich, both of Michigan Technological University in Houghton, found the wolves feeding on a freshly-killed moose calf. “We were very lucky,” Peterson says. “There was no mystery left in terms of the wolf population,” or what they were eating.last_img read more