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Hobohm, Carsten ; Moro-Richter, Michaela ; Beierkuhnlein, Carl:
Distribution and Habitat Affinity of Endemic and Threatened Species : Global and European Assessment.
In: Hobohm, Carsten
(Hrsg.):
Perspectives for Biodiversity and Ecosystems. -
Cham
: Springer Nature
,
2021
. - S. 233-277
. - (Environmental Challenges and Solutions
)
ISBN 978-3-030-57709-4
DOI: https://doi.org/10.1007/978-3-030-57710-0_11
Abstract
Realms of species, assemblages, and whole ecosystems are threatened by human activities such as damage, resource use, pollution, introduction of neobiota, and also by natural processes and disasters. We present an assessment of distribution patterns and numbers of endemic and threatened species with respect to their habitat affinity and threats at global and European scales.
We used five databases for analyses: IUCN Red List of Threatened Species (2018, 2019a, b, c), European Red List of Habitats (Janssen et al. 2016) including fact sheets, Plant Endemism Assessment of Red List Habitats in Europe (PEARL), Endemic Vascular Plants in Europe (EvaplantE), and a global database on hyperendemics (Hypedata). The first two are available on the internet, the latter are own databases. Hypedata is taxonomically and geographically not restricted, PEARL and EvaplantE are focusing on the situation of vascular plant species in Europe.
The categorization of habitat types is necessary to get a classification scheme and a quantitative relationship with respect to the meaning of habitats for endemic and threatened species. Furthermore, such definitions and categorisations are helpful to describe consequences in environmental politics and management. Thus, the first part is related to classification and definition of habitat types which is predominantly in accordance with the highest level of other classification schemes.
We here introduce the term hyperendemism in the ecological-biogeographical context. Hyperendemics are taxa with an extremely small range (<1 km2) or a very small population size (<50 mature individuals). The list presented here is just the kick-of of processing a database.
At the moment the list represents 551 species, i.e. 494 plant species (482 vascular plants, 10 bryophytes, 2 lichens), 56 animal species (41 vertebrates, 15 invertebrates), and 1 fungus.
355 hyperendemic species live on islands, 196 on mainland including mainland of Australia.
Many hyperendemics are assumed to be remnant populations of species with a much wider range in the past. Some are identified as neo-hyperendemics that evolved during the late Pleistocene or early Holocene, and simply have not been able to enlarge their range, yet.
Because of the limited range of occurrence or population size the survival of hyperendemics and local endemics should have highest priority. Therefore, any risk including the probability of introduction of alien species, pathogens and biological tourism should be minimized. On the other hand, measures to enlarge the populations and safekeeping of genetic material should systematically be planned, organized and intensified, for example with support from botanical gardens, seed banks, zoos and aquariums.
General needs and consequences for different habitat types can only be specified very broadly. Thus, the consequences delineated here may serve as a basis for discussion and should be assessed in every case at local to regional scales.
Forest, shrubland and freshwater habitats harbour most critically endangered species on Earth. However, the importance and endangerment of habitats and associated species differ considerably from region to region. For example, in Europe and Central Asia habitat types of open and semi-open landscapes harbour much more endemic and threatened species than forests.
Globally, agriculture, land use change, forestry, and biological resource use are the most threatening factors for biodiversity. Many terrestrial ecosystems are directly and indirectly affected e.g. by conversion, tilling, plantations, construction of roads and buildings, and intensification of use, including increasing effects of physical, chemical and biological processes.
In general, the risk of invasive species from abroad for the survival of native species is higher where alien species represent niches which have not been occupied before, and is increasing with the introduction of hitherto not represented functional roles (e.g. predators). Thus, many bird species on islands became extirpated by introduced animals such as rat, cat, goat, snake or others simply because the native and often ground-breeding birds have had no experience with such aggressive predators in their evolutionary life before. In all these cases competition was not the problem but the representation of a new node in the food web. Therefore, the situation on islands has to be assessed and evaluated in a different way compared to most mainland regions. Across Europe, for example, no native species became extinct because of the introduction of an alien species.
For hyperendemics invasive and other problematic species, genes and diseases are the most important threat category.
Climate change and severe weather might especially be relevant in combination with other threats.
In general, threats and the composition of endangered species differ with respect to habitat type. Thus, also consequences and recommendations have to be specified with respect to locality, habitat type and target species.
For the survival of critically endangered species it is extremely important that the range of protected habitat types should be enlarged. According to different recommendations of environmental organizations the protected area of all habitat types should exceed the 10% level at regional and global scales. In many cases, the protection of the diversity of habitat types at the landscape scale is the best measure to preserve species diversity. For protecting all species on Earth this alone, however, would definitely not be enough.