The high fidelity of the cetacean stranding record: insights into measuring diversity by integrating taphonomy and macroecology

Abstract

Stranded cetaceans have long intrigued naturalists because their causation has escaped singular explanations. Regardless of cause, strandings also represent a sample of the living community, although their fidelity has rarely been quantified. Using commensurate stranding and sighting records compiled from archived datasets representing nearly every major ocean basin, I demonstrated that the cetacean stranding record faithfully reflects patterns of richness and relative abundance in living communities, especially for coastlines greater than 2000 km and latitudinal gradients greater than 48. Live-dead fidelity metrics from seven different countries indicated that strandings were almost always richer than live surveys; richness also increased with coastline length. Most death assemblages recorded the same ranked relative abundance as living communities, although this correlation decreased in strength and significance at coastline lengths greater than 15 000 km, highlighting the importance of sampling diversity at regional scales. Rarefaction analyses indicated that sampling greater than 10 years generally enhanced the completeness of death assemblages, although protracted temporal sampling did not substitute for sampling over longer coastlines or broader latitudes. Overall, this global live -dead comparison demonstrated that strandings almost always provided better diversity information about extant cetacean communities than live surveys; such archives are therefore relevant for macroecological and palaeobiological studies of cetacean community change through time.

Bycatch and strandings programs as ecological indicators for data-limited cetaceans

“…In recent years, it has been increasingly realised that critical demographic (Mannocci et al, 2012), genetic and species diversity information (Pyenson, 2010(Pyenson, , 2011 can be obtained from relatively inexpensive strandings networks, particularly if they encompass a large area and are collected over long time periods. Strandings records also provide information on species that are rarely observed in the wild (Thompson et al, 2013) and the frequency of occurrence of species within an area (Maldini et al, 2005).…”

Biology in the Anthropocene: Challenges and insights from young fossil records

“…Although death assemblages pool temporal variability and some spatial variability in local living assemblages, they still accurately detect environmental gradients and more closely approximate the species composition and abundance structure of the larger metacommunity, a stubborn data gap for biologists. Mammal death assemblages collected from open ground, raptor roosts, and marine flotsam have comparable ecological fidelity, with habitat-to regional-scale spatial resolution (50)(51)(52). Some clades with delicate skeletons have intrinsically poor preservation, of course, requiring analytic partitioning, and postmortem attenuation is stronger in some settings than others.…”

Review of thirty-two years of toothed whale strandings in Santa Catarina, southern Brazil (Cetacea: Odontoceti)

“…According to Peltier et al (2012), the number of dead cetaceans that reach the coastline and get stranded depend on several parameters such as currents, distance from the coast, atmospheric pressure, wind speed and carcass buoyancy. Coastal species are less influenced by marine currents and coastal winds, commonly stranding near their home ranges (Pyenson 2010, 2011, Prado et al 2013. However, for areas with strong wind and wave dynamics, such as the cold fronts that occur in southern Brazil (rodrigues et al 2004), carcass drift may play a large role in the stranding dynamics.…”