An ecosystem engineer, the beaver, increases species richness at the landscape scale

Abstract

Ecosystem engineering - the physical modification of habitats by organisms - has been proposed as an important mechanism for maintaining high species richness at the landscape scale by increasing habitat heterogeneity. Dams built by beaver (Castor canadensis) dramatically alter riparian landscapes throughout much of North America. In the central Adirondacks, New York, USA, ecosystem engineering by beaver leads to the formation of extensive wetland habitat capable of supporting herbaceous plant species not found elsewhere in the riparian zone. We show that by increasing habitat heterogeneity, beaver increase the number of species of herbaceous plants in the riparian zone by over 33% at a scale that encompasses both beaver-modified patches and patches with no history of beaver occupation. We suggest that ecosystem engineers will increase species richness at the landscape scale whenever there are species present in a landscape that are restricted to engineered habitats during at least some stages of their life cycle.

Ecological impact of Eurasian beaver (Castor fiber) activity on macroinvertebrate communities in Lithuanian trout streams

“…Wright et al [11] predicted that the impact of beavers on invertebrate species richness might be less relevant in landscapes where lentic freshwater habitats independent of beaver activity occur. They also predicted that the total species richness would decrease if beavermodified wetlands dominated the riparian ecosystem, as the number of unengineered patches may not be sufficient to support the entire complement of species.…”

Benthic Habitat Modification through Excavation by Red Grouper, Epinephelus morio, in the Northeastern Gulf of Mexico

“…This phenomenon is well known among terrestrial organisms ranging from beavers to prairie dogs [11,12]. Beavers, for example, build dams to protect themselves and their broods from predation and weather and, in the process, alter the local hydrology and habitat heterogeneity for fishes, invertebrates, and migrating waterfowl [11] while increasing diversity of herbaceous plants over broader regions [13].…”

Advies inrichting en beheer beekdal Geeserstroom

“…Voor de fauna zijn binnen niet verdroogde moeras-of broekbossen grofweg twee groepen van belang: broekbossen in natte beekdalen, waarbij zowel inundatie met kwelwater als met beekwater plaatsvindt (zie o.a. Wright et al 2002) en broekbossen in kwelrijke beekdalen en laagtes in het dekzandgebied, die nooit of vrijwel nooit overstromen met beekwater en alleen gevoed worden door kwelwater (tabel 4.3).…”