Multispecies curiosities and ethnographies

Příspěvek popisuje vznik vícedruhové etnografie jako formy znásobení zkušeností a popisů za hranicemi lidského druhu. Navzdory tomu, že definice vícedruhovosti je poměrně nedávná, autor v článku tvrdí, že zájem o začlenění jiných než lidských bytostí do etnografického úsilí se datuje již od počátku disciplíny. Příkladem tohoto zájmu je text The American Beaver and His Works (Americký bobr a jeho práce) napsaný roku 1868 Henrym Morganem, v němž autor tato zvířata účinně zařazuje do své etnografie. Článek pojednává o tom, že vícedruhový přístup může podpořit předefinování hlavních rysů etnografického výzkumu.

Impacts of a Non-indigenous Ecosystem Engineer, the American Beaver (Castor canadensis), in a Biodiversity Hotspot

Non-native species having high per capita impacts in invaded communities are those that modulate resource availability and alter disturbance regimes in ways that are biologically incompatible with the native biota. In areas where it has been introduced by humans, American beaver (Castor canadensis) is an iconic example of such species due to its capacity to alter trophic dynamics of entire ecosystems and create new invasional pathways for other non-native species. The species is problematic in several watersheds within the Southern California-Northern Baja California Coast Ecoregion, a recognized hotspot of biodiversity, due to its ability to modify habitat in ways that favor invasive predators and competitors over the region's native species and habitat. Beaver was deliberately introduced across California in the mid-1900s and generally accepted as non-native to the region up to the early 2000s; however, articles promoting the idea that beaver may be a natural resident have gained traction in recent years, due in large part to the species' charismatic nature rather than by presentation of sound evidence. Here, we discuss the problems associated with beaver disturbance and its effects on conserving the region's native fauna and flora. We refute arguments underlying the claim that beaver is native to the region, and review paleontological, zooarchaeological, and historical survey data from renowned field biologists and naturalists over the past ~160 years to show that no evidence exists that beaver arrived by any means other than deliberate human introduction. Managing this ecosystem engineer has potential to reduce the richness and abundance of other non-native species because the novel, engineered habitat now supporting these species would diminish in beaver-occupied watersheds. At the same time, hydrologic functionality would shift toward more natural, ephemeral conditions that favor the regions' native species while suppressing the dominance of the most insidious invaders.

The evolution of Castorids (Mammalia, Rodentia) in the Republic of Moldova

Beavers first appear in Asia, where fossil remains date back to the Eocene (33-36 million years ago). The most widespread Pleistocene giant beaver fossils were Siberian beavers – Trogontherium cuvieri and the North American beaver – Castoroides ohioensis. According to recent research, the oldest beavers in the Republic of Moldova are known from the deposits of Sarmatian (11.5 million years) – Steneofiber aff. depereti Mayeri, Chalicomys jaegeri (Kaup), Palaeomys castoroides Kaup, Trogontherium minutum minutum Franzet et Storch., T. minutum rhenanum Franzet et Storch. and Monosaulax cainarensis Lungu. In the Meotian (8.7-5.0 million years) only two species were recorded – Trogontherium minutum rhenanum Franzet et Storch. and Castor aff. praefiber Deperet. et Lungu.

The North American Beaver (Castor canadensis) is Recolonizing the Llano Estacado

Five millennia ago, the North American Beaver (Castor canadensis) was extirpated from the Southern High Plains by droughts. Beaver were found to be largely absent from the Llano Estacado, despite exhaustive search efforts. Here we report the first definitive evidence of an extant C. canadensis population recolonizing the Llano Estacado.

Western Message Petroglyphs indicate historic beaver presence in a San Francisco Bay Area watershed

Recent museum, archaeological, and observer record evidence suggests that North American beaver (Castor canadensis) were historically native to the watersheds of California’s coast, including San Francisco Bay. A wide variety of animals are abundantly represented in Native American petroglyphs and pictographs with their representations fulfilling intentions ranging from the mundane to ceremonial and mythological purposes. However, beaver symbols are poorly represented in California rock art and absent from the San Francisco Bay Area. A novel record, in the form of Western Message Petroglyphs, suggests that a beaver lodge was present in the late nineteenth century in the Alameda Creek watershed, potentially the last evidence of beaver prior to their extirpation in the region by the fur trade.

Distribution patterns of the native Eurasian and the non-native North American beaver in Finland—possible factors affecting the slow range expansion of the native species

Distribution patterns of species are affected by resource availability, dispersal, disturbance and population dynamics. The smaller population size and range of the native Eurasian beaver (Castor fiber) compared to the non-native North American beaver (Castor canadensis) in Finland raise questions on reasons for the slower range expansion of the native species. We compared the population growth rates and the spread of both species from their release sites. We also studied the factors possibly affecting the spread of the Eurasian beaver in South western Finland in more detail. We found that the North American beaver has spread longer distances than the Eurasian beaver, but we did not find evidence for movement barriers constraining the expansion rate of the native species. Lack of high-quality habitats does not seem to constrain the expansion to nearby areas either. Despite this, the Eurasian beaver population has grown to a high density close to its reintroduction site, and it has started to spread to novel areas only recently. We conclude that the expansion of the native beaver in Finland seems to be controlled by factors other than those related to barriers for movement: movement behavior and population dynamics, which require further investigation.