TY - CHAP
T1 - Movement Behavior of Manatees and Dugongs
T2 - I. Environmental Challenges Drive Diversity in Migratory Patterns and Other Large-Scale Movements
AU - Deutsch, Charles J.
AU - Castelblanco-Martinez, Delma Nataly
AU - Groom, Rachel
AU - Cleguer, Christophe
PY - 2022/5/1
Y1 - 2022/5/1
N2 - The seemingly unhurried nature of manatees and dugongs belies their great capacity for undertaking long-distance journeys, often repeatedly in the form of round-trip seasonal migrations, but sometimes as movements independent of seasonal influence. Unique attributes of sirenian biology that interact with features of their environment to mold patterns of movement and habitat use include herbivory, limited thermoregulatory physiology for coping with cold and, for manatees, an apparent need to ingest fresh water. Manatees and dugongs are remarkably adaptable in their large-scale movement behavior, as manifested by the considerable variation in the occurrence and extent of migrations across populations within species, and among individuals within populations. Some populations and individuals are relatively sedentary year-round, whereas others migrate hundreds of kilometers between seasonal ranges. The environmental selective pressures driving seasonal movements vary across species, climates, and ecosystems, but are most commonly generated by predictable fluctuations in water temperature (Florida manatee, some dugong populations), rainfall (coastal populations of Antillean and African manatees), or water level (inland populations of all 3 manatee species living in flood-pulse river systems) over the annual cycle. In each case there is a season (winter, dry, or low-water) of heightened environmental stress where the animals’ range is restricted to areas around a key limiting resource (warm water, fresh water, or deep water), and forage is therefore less available or of lower nutritional quality. Because dugongs are strictly marine and do not require fresh water, they experience fewer seasonally imposed constraints and are less likely to migrate than manatees. Consequently, the large-scale movements of dugongs seem more stochastic; assessing the status of forage over a wide area through occasional long-distance exploratory forays may represent a behavioral adaptation to periodic extensive declines in seagrass caused by extreme weather events. The available evidence for manatees indicates strong fidelity to seasonal or year-round ranges across years. A common finding from tracking studies is the existence of considerable variation in large-scale movement behavior among and within individuals, which should confer adaptability to environmental change in the short term and provide the raw material for evolutionary change over the long term.
AB - The seemingly unhurried nature of manatees and dugongs belies their great capacity for undertaking long-distance journeys, often repeatedly in the form of round-trip seasonal migrations, but sometimes as movements independent of seasonal influence. Unique attributes of sirenian biology that interact with features of their environment to mold patterns of movement and habitat use include herbivory, limited thermoregulatory physiology for coping with cold and, for manatees, an apparent need to ingest fresh water. Manatees and dugongs are remarkably adaptable in their large-scale movement behavior, as manifested by the considerable variation in the occurrence and extent of migrations across populations within species, and among individuals within populations. Some populations and individuals are relatively sedentary year-round, whereas others migrate hundreds of kilometers between seasonal ranges. The environmental selective pressures driving seasonal movements vary across species, climates, and ecosystems, but are most commonly generated by predictable fluctuations in water temperature (Florida manatee, some dugong populations), rainfall (coastal populations of Antillean and African manatees), or water level (inland populations of all 3 manatee species living in flood-pulse river systems) over the annual cycle. In each case there is a season (winter, dry, or low-water) of heightened environmental stress where the animals’ range is restricted to areas around a key limiting resource (warm water, fresh water, or deep water), and forage is therefore less available or of lower nutritional quality. Because dugongs are strictly marine and do not require fresh water, they experience fewer seasonally imposed constraints and are less likely to migrate than manatees. Consequently, the large-scale movements of dugongs seem more stochastic; assessing the status of forage over a wide area through occasional long-distance exploratory forays may represent a behavioral adaptation to periodic extensive declines in seagrass caused by extreme weather events. The available evidence for manatees indicates strong fidelity to seasonal or year-round ranges across years. A common finding from tracking studies is the existence of considerable variation in large-scale movement behavior among and within individuals, which should confer adaptability to environmental change in the short term and provide the raw material for evolutionary change over the long term.
KW - migration
KW - residency
KW - seasonal movements
KW - movement behaviour
KW - large-scale
KW - site fidelity
KW - natal philopatry
KW - individual variation
KW - satellite tracking
U2 - 10.1007/978-3-030-90742-6_5
DO - 10.1007/978-3-030-90742-6_5
M3 - Chapter
SN - 978-3-030-90741-9
T3 - Ethology and Behavioral Ecology of Marine Mammals (EBEMM)
SP - 155
EP - 231
BT - Ethology and Behavioral Ecology of Sirenia
A2 - Marsh, Helene
PB - Springer
CY - Cham
ER -