Umbrella species: “a species whose conservation confers protection to a large number of naturally co-occurring species.” Roberge and Angelstam (2003)
In the face of increasing rates of habitat loss, fragmentation and species extinctions, the maintenance of global biodiversity has become one of our most pressing issues. In an effort to ensure the persistence of biodiversity, practitioners, biologists and managers have developed shortcuts for applied conservation efforts based on focal species. The umbrella species concept is one such shortcut.
Focal species concepts are advantageous to conservation planners and practitioners as they conceptually permit the monitoring of a few select species rather than carrying out costly and time-consuming ecosystem-wide surveys. The underlying assumptions of the umbrella species concept state that meeting the requirements of the focal species is sufficient to meet the requirements of a number of co-occurring species. However, umbrella species do not fit a single biological profile and it is highly unlikely that a single species will confer benefits to all sympatric species.
Potential umbrella candidates should exhibit certain traits: species should be neither rare nor ubiquitous, should be sensitive to anthropogenic disturbance and account for a mean proportion of occurring species. Combining these attributes ensures that the focal species is common enough to confer adequate protection to sympatric species and protect similarly sensitive species from disturbance. These guidelines however are simply that. There is no strict definition, nor combination of life history traits commonly used to characterise an umbrella species.
Choosing umbrella species is often a reactive rather than proactive process as priority is often placed on endangered or threatened taxa. Large visible species such as mammals and birds are frequently the subject of investigations into the effectiveness of the umbrella species concept, possibly because such species are more commonly targeted by conservation efforts and frequently receive a disproportionate amount of funding and publicity. In such instances, the efficacy of the species to act as an umbrella is often determined post-hoc rather than basing management decisions on specific research and objectives. There is often a basic assumption inherent to this approach; that the minimum-area requirements for large species are likely to coincide and overlap with the area requirements of those species which are seemingly beneath the umbrella.
The umbrella species concept is increasingly used in synonymy with other focal species concepts. The most common perceived overlap occurs between umbrella and keystone species. Keystone species are those species whose presence is a key factor in maintaining the ecological structure of a community, often disproportionately so. Removal of a keystone species results in rapid and dramatic alterations in associated communities. Based on this definition and the given definition of the umbrella species concept it is evident that the two concepts are not as readily interchangeable as is often assumed. Protection of a keystone species does not necessarily confer protection to all other species which occur within its range. Similarly, removal of an umbrella species will not necessarily cause a dramatic change in community composition. It should be noted that a species can indeed fulfil both roles. North American grizzly bears are cited as keystone species for the roles they play in dispersing nutrients away from rivers (in faeces) and are also classed as umbrella species due to their trophic status and typical range size.
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