label for small areas with narrow ranges of endemic species. In this sense all areas
with at least one hyperendemic species or subspecies might also be designated as
micro-hotspots, where hyperendemism is the trait and micro-hotspot is the spatial
correlate to it.
Hyperendemic species can result from declining populations, local extinctions
within the former range of distribution. In this case they can be understood as
remnant populations. Such remnant populations that experience a severe decline of
individuals are likely to have lost genetic diversity within the entire species (Price
and Hadfield 2014).
Small spatial ranges as a result of declining populations may be caused by natural
processes such as volcanic eruption on an island. However, human pressure such as
land use change, fragmentation, introduced herbivores, predators or diseases seem to
be a major contribution to habitat loss and hyperendemism today (IUCN 2019c).
Hyperendemics can also emerge from recent speciation. Neo-hyperendemics
result from recent speciation processes, e.g. apomictic species such as members of
the genera Hieracium or Sorbus across Europe (Gregor 2013).
Concerning palaeo-hyperendemism, species evolved long-time ago but have not
managed to extend their distribution area or the range decreased over time. Here,
species with very specific habitat requirements can be listed. In some cases of old
phyla it is difficult to find out if this species has been more widespread in the past
(e.g. Wollemia nobilis, cf. Woodford 2000).
In cases of occasional very distant populations, fake-hyperendemics have been
temporarily created by scientists. An extremely small population of a Marsilea
species was considered to be a hyperendemic species when it was recorded for the
first time on the Azores. Later on it was identified to belong to the Australian species
Marsilea hirsuta, a fact that was not to be expected because it is unlikely for plant
species to disperse across hemispheres and oceans. Thus, not only the former species
name of the Azorean population became invalid, the label of the species changed
from native with high conservation priority to an introduced species with low
conservation value (Schaefer et al. 2011). This illustrates that categories are dependent on the respective state of knowledge.
A short version of the preliminary list of hyperendemics is represented in the
Appendix.
Through direct and indirect impacts, humans have modified habitats for species in
all biomes but with differences in intensity and effect size. Habitats are subject to
land use, degradation, pollution and even complete destruction. Resources were
exploited, alien species were introduced, nutrients were added, soil eroded, trophic
cascades were disrupted.
Here, we relate patterns of endemism and threatened species to habitat types of
global importance. In order to generalize as well over specific and local conditions as
to cover a broad range of ecosystems we classify major habitat types for species. For
the characterization of habitats we used different classification schemes, and tried to
find a clear description and definition (cf. e.g. Davies et al. 2004, Janssen et al.
2016), IUCN Red List 2018, 2019a, b, c).
238
C. Hobohm et al.
with at least one hyperendemic species or subspecies might also be designated as
micro-hotspots, where hyperendemism is the trait and micro-hotspot is the spatial
correlate to it.
Hyperendemic species can result from declining populations, local extinctions
within the former range of distribution. In this case they can be understood as
remnant populations. Such remnant populations that experience a severe decline of
individuals are likely to have lost genetic diversity within the entire species (Price
and Hadfield 2014).
Small spatial ranges as a result of declining populations may be caused by natural
processes such as volcanic eruption on an island. However, human pressure such as
land use change, fragmentation, introduced herbivores, predators or diseases seem to
be a major contribution to habitat loss and hyperendemism today (IUCN 2019c).
Hyperendemics can also emerge from recent speciation. Neo-hyperendemics
result from recent speciation processes, e.g. apomictic species such as members of
the genera Hieracium or Sorbus across Europe (Gregor 2013).
Concerning palaeo-hyperendemism, species evolved long-time ago but have not
managed to extend their distribution area or the range decreased over time. Here,
species with very specific habitat requirements can be listed. In some cases of old
phyla it is difficult to find out if this species has been more widespread in the past
(e.g. Wollemia nobilis, cf. Woodford 2000).
In cases of occasional very distant populations, fake-hyperendemics have been
temporarily created by scientists. An extremely small population of a Marsilea
species was considered to be a hyperendemic species when it was recorded for the
first time on the Azores. Later on it was identified to belong to the Australian species
Marsilea hirsuta, a fact that was not to be expected because it is unlikely for plant
species to disperse across hemispheres and oceans. Thus, not only the former species
name of the Azorean population became invalid, the label of the species changed
from native with high conservation priority to an introduced species with low
conservation value (Schaefer et al. 2011). This illustrates that categories are dependent on the respective state of knowledge.
A short version of the preliminary list of hyperendemics is represented in the
Appendix.
Through direct and indirect impacts, humans have modified habitats for species in
all biomes but with differences in intensity and effect size. Habitats are subject to
land use, degradation, pollution and even complete destruction. Resources were
exploited, alien species were introduced, nutrients were added, soil eroded, trophic
cascades were disrupted.
Here, we relate patterns of endemism and threatened species to habitat types of
global importance. In order to generalize as well over specific and local conditions as
to cover a broad range of ecosystems we classify major habitat types for species. For
the characterization of habitats we used different classification schemes, and tried to
find a clear description and definition (cf. e.g. Davies et al. 2004, Janssen et al.
2016), IUCN Red List 2018, 2019a, b, c).
238
C. Hobohm et al.