Our Living Resources
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Thomas Kitchin/Tom Stack &Thomas Kitchin/Tom Associates© Mammals Overview post-Columbian era, most North American by Many mammalian popula- mammalian populations significantly declined, Science Editor tion studies have been initiated to determine a primarily because of their inability to adapt and species’ biological or ecological status because compete with early European land-use practices Benjamin N. Tuggle of its perceived economic importance, its abun- and pressures. U.S. Fish and Wildlife Habitat modification and destruction during dance, its threatened or endangered state, or Service because it is viewed as our competitor. As a the settlement of North America occurred very result, data on mammalian populations in North slowly initially. Advances in agriculture and Chicago Illinois America have been amassed by researchers, engineering accelerated the loss or modification Field Office naturalists, trappers, farmers, and land man- of habitats that were critical to many species in agers for years. climax communities. These landscape transfor- Barrington, Illinois 60010 Inventory and monitoring programs that pro- mations often occurred before we had any duce data about the status and trends of mam- knowledge of how these environmental changes malian populations are significant for many rea- would affect native flora and fauna. Habitat sons. One of the most important reasons, how- alterations were almost always economically ever, is that as fellow members of the most driven and in the absence of land-use regula- advanced class of organisms in the animal king- tions and conservation measures many species dom, the condition of mammal populations were extirpated. most closely reflects our condition. In essence, In addition to rapid and sustained habitat and mammalian species are significant biological landscape changes from agricultural and silvi- indicators for assessing the overall health of cultural practices, other factors such as unregu- advanced organisms in an ecosystem. lated hunting and trapping, indiscriminate Habitat changes, particularly those initiated predator and pest control, and urbanization also by humans, have profoundly affected wildlife contributed significantly to the decline of once- populations in North America. Though Native bountiful mammalian populations. These prac- Americans used many wildlife species for food, tices, individually and collectively, have been clothing, and trade, their agricultural and land- directly correlated with the decline or extinction use practices usually had minimal adverse of many sensitive species. effects on mammal populations during the pre- The turn of the century brought a new focus European settlement era. In general, during the on conservation efforts in this country. Contents Article Page Contents Article Page 94 Mammals— Our Living Resources Populations of some species, such as the white- gram that coordinates data on the status and tailed deer (Odocoileus virginianus), showed trends of our natural resources is critical to suc- marked recovery after regulatory and conserva- cessfully manage habitats that support a diverse tion strategies began. Ardent wildlife manage- array of plant and animal species. ment and conservation programs, started pri- This section provides knowledge on the sta- marily for game species, have increased our tus and trends of some higher vertebrate species knowledge and understanding of species and that occupy some of this country’s most diverse habitat interactions. Conservation programs ecosystems. Many articles discuss historical have also positively affected many species that and present species distribution, while others share habitat with the target species the pro- discuss the need for further research to fill our grams are designed to aid. To complement these gaps of knowledge regarding the species. The efforts, however, integrated regulatory legisla- articles cover a range of mammal species, some tion and conservation policies that specifically that have benefited greatly from past conserva- help sustain nontarget species and their habitats tion efforts, and others that are now threatened are still imperative. or endangered, with the effort to recover them The increased emphasis on the importance just beginning. Some species have been directly of managing for biological diversity and adopt- affected by habitat loss or modification, others ing an ecosystem approach to management has by past hunting and trapping pressures. enhanced our efforts to move from resource- We should not forget that our survival management practices that are oriented to sin- depends on wildlife, particularly higher verte- gle species to strategies that focus on the long- brates, nor should we forget that the status of term conservation of native populations and wildlife populations serves as an advance indi- their natural habitats. Thus, an integrated and cator of overall environmental quality. comprehensive inventory and monitoring pro- Marine t least 35 species of marine mammals are NMFS Assessments Afound along the U.S. Atlantic coast and in Mammals the Gulf of Mexico: 2 seal species, 1 manatee, The National Marine Fisheries Service and 32 species of whales, dolphins, and por- (NMFS), an agency within the National Oceanic poises (see Table 1 for status of selected and Atmospheric Administration (NOAA), con- by species). Seven of these species are listed as ducts research and status studies on many of Anne Kinsinger endangered under the Endangered Species Act these marine mammals under the authorities of National Biological Service (ESA). At least 50 species of marine mammals the Magnuson Fisheries Conservation and are found in U.S. Pacific waters: 11 species of Management Act, the Marine Mammal Summarized from National seals and sea lions; walrus; polar bear; sea otter; Protection Act (MMPA), and the ESA. The Oceanic and Atmospheric and 36 species of whales, dolphins, and por- results of the status surveys include information Administration (1994) poises; 11 species are listed as endangered or required by the MMPA and the ESA on abun- threatened under the ESA (see Table 2 for the dance (population size); status (as compared status of selected species). with historical levels or current viability); trends (changes in abundance); and status in U.S. waters. These results, published annually by Table 1. Status of selected Atlantic and Gulf of Mexico coast species of marine mammals. NOAA, are the basis for this summary (NOAA Official status in Species and geographic area Abundance Status Trends 1994). designated U.S. waters Fin whale, NE U.S. 5,200 Unknown Unknown Endangered* Estimates of abundance in U.S. waters are Possibly 65% of 1850 available for many, though not all, marine mam- Humpback whale, NW Atlantic 5,100 (2,888-8,112) Unknown Endangered* population mal species. Information on status and trends, Northern right whale, NW Probably <5% of original 350 Unknown Endangered* Atlantic number however, is extremely limited because so little is Pilot whales, NE U.S. Unknown Unknown Unknown known of the basic life history of many marine Bottlenose dolphin mammal species that scientists can determine Possibly down by 50% NE U.S. coastal type Unknown Unknown Depleted** neither status nor whether a population estimate 1987-88 represents a healthy, sustainable population. NE U.S. offshore type 10,000-13,000 Unknown Gulf of Mexico (offshore and Possibly down by 50% Moreover, long-term trends in many populations 35,000-45,000 Unknown coastal types) 1987-88 cannot be determined because historical popula- Whitesided dolphin, NE U.S. 27,600 Unknown Unknown tion data are not available. Spotted dolphin, NE U.S. 200 Unknown Unknown The NMFS provides assessments for 139 Harbor porpoise, Gulf of Maine 47,200 Unknown Unknown Proposed as threatened* Harbor seal, NE U.S. 26,000 Unknown Increasing stocks (i.e., populations of species or groups of Beaked whales (six species in species that are treated together for manage- Unknown Unknown Unknown U.S. waters) ment) of marine mammals; the status of 120 *Endangered Species Act. stocks is unknown, and trend data are only **Marine Mammal Protection Act. Contents Article Page Contents Article Page Our Living Resources — Mammals 95 available for 19 stocks. The recently reautho- Table 2. Status of selected Pacific coast species of marine mammals. rized MMPA requires the NMFS to conduct Official status in des- Species and area Abundance Status Trends periodic assessments of marine mammal stocks ignated U.S. waters that occur in U.S. waters. For this reason, better Fin whale 935 Unknown Unknown Endangered* Humpback whale, E ~1,400 Probably less than 15% of Unknown Endangered* status and trends data are likely to become Pacific 1850 population available over the next few years. Northern right whale Unknown Unknown Unknown Endangered* Abundance and status data for selected Bowhead whale, W. 7,500 About 40% of 1848 Increasing at 3.1%/yr, Endangered* marine mammals are summarized in Table 1 Arctic population size 1978-88 20,869 (19,200- Recovered to historical 1845 Increasing at 3.3%/yr, Removed from ESA Grey whale (Atlantic species) and Table 2 (Pacific species). 22,700) abundance levels 1968-88 listing June 1994 Trend data are mixed, but a number of conser- E. tropical Pacific dolphins vation success stories have come from marine NE spotted 731,000 Depleted Declining mammals. The bowhead and grey whales have W/S spotted 1,298,000 Unknown Stable Coastal spotted 30,000 Unknown Stable shown significant population increases, as have E