EXECUTIVE SUMMARY
Water-trumpets (the genus Cryptocoryne), include a total of 115 currently recognised taxa, represented
by 68 species, 29 varieties, 14 hybrids or hybrid complexes and 4 nothovarieties. However, surveys, field
recording and painstaking ex-situ research are constantly finding new taxa and so these figures will have
changed even as this action plan is published. Cryptocoryne taxa occur from western India east to
southern China and south through South-east Asia and the Philippines to New Guinea. Many taxa are
known from single locations or even single collections, while two are known only from horticulture with
their native range unknown.
Most of the species in the genus are restricted to rainforest rivers, from small headwater streams to a
few which occur in large rivers such as the Irrawaddy, the Mekong and their tributaries. While rainforest
and its destruction has received much publicity, there has been relatively little focus on forest rivers.
These are typically more threatened than the forest itself, being vulnerable to issues such as nutrient
enrichment and increased turbidity as a result of selective logging, mineral extraction and mining, whilst
often being devastated by secondary impacts of human use of forest habitats. Other species are dependent
upon habitats such as freshwater swamp forest which is threatened throughout the region. Species which
occur only in a single watercourse are highly vulnerable to even quite local changes in hydrology, water
quality and even riparian habitat modification.
The distribution of Cryptocoryne taxa is not uniform in the region and a small number of areas support
particularly high genetic diversity. The greatest species diversity occurs in Borneo, mainly in western
Kalimantan and Sarawak where 26 species, six varieties and six natural hybrid combinations are known
followed by Sumatra (Sumatera) with 16 species, three varieties and four natural hybrid combinations
and Sri Lanka with ten species and one natural hybrid combination. This contrasts with Indochina with
only seven species, but nine varieties, as well as with New Guinea with two species and two varieties,
however taxonomic work is showing that there are new taxa to be described in a number of areas. This
diversity is reflected in the distribution of widespread taxa, as compared to local endemics. Areas such
as western India and Indochina support a higher proportion of widespread taxa, whereas Borneo and
Sumatra support high proportions of local endemics.
Throughout their range, Cryptocoryne taxa are mainly threatened by six types of action: clearance of
natural habitats, agricultural intensification (often gradually following on from selective logging of
natural forest and then small-scale clearance), development, uncontrolled and/or illegal collection,
hydrological modification and water use (abstraction). The most significant threat to Cryptocoryne
populations throughout their range is the degradation of habitats within which wetlands supporting
Cryptocoryne populations occur and their conversion to industrial-scale plantations. However the
relationship between habitat degradation and the survival of some Cryptocoryne populations is not
simple. Many Cryptocoryne populations appear able to survive some aspects of the conversion of forest
to industrial-scale plantations, small-holder farming and even urbanisation, with populations persisting
in drainage ditches in highly modified landscapes, such as in northern Kerala in western India. However,
these are likely to be sparse remnants of formerly larger and more extensive populations.
This Conservation Action Plan is based on preparation of Red List assessments, employing the IUCN
Criteria, for all species, varieties and hybrid combinations known at the time or preparation. Assessments
of species and varieties were submitted for publication in 2022. The information included in these
assessments was then compiled to enable analysis of threats, leading to development of a suite of
proposals for conservation action for species or regional populations. The action plan is presented in the
following sections:
An introduction to the Conservation Action Plan.
A summary characterisation of the genus Cryptocoryne.
An overview of the conservation status of all known taxa, based on Red List assessments.
Analysis of the threats affecting Cryptocoryne populations.
A strategic plan presenting an overview of potential action at a range of levels down to individual
regions and taxa.
A list of references used in putting together the Action Plan.
An appendix presenting the threat status assigned to each taxon assessed.
Water-trumpets (the genus Cryptocoryne), include a total of 115 currently recognised taxa, represented
by 68 species, 29 varieties, 14 hybrids or hybrid complexes and 4 nothovarieties. However, surveys, field
recording and painstaking ex-situ research are constantly finding new taxa and so these figures will have
changed even as this action plan is published. Cryptocoryne taxa occur from western India east to
southern China and south through South-east Asia and the Philippines to New Guinea. Many taxa are
known from single locations or even single collections, while two are known only from horticulture with
their native range unknown.
Most of the species in the genus are restricted to rainforest rivers, from small headwater streams to a
few which occur in large rivers such as the Irrawaddy, the Mekong and their tributaries. While rainforest
and its destruction has received much publicity, there has been relatively little focus on forest rivers.
These are typically more threatened than the forest itself, being vulnerable to issues such as nutrient
enrichment and increased turbidity as a result of selective logging, mineral extraction and mining, whilst
often being devastated by secondary impacts of human use of forest habitats. Other species are dependent
upon habitats such as freshwater swamp forest which is threatened throughout the region. Species which
occur only in a single watercourse are highly vulnerable to even quite local changes in hydrology, water
quality and even riparian habitat modification.
The distribution of Cryptocoryne taxa is not uniform in the region and a small number of areas support
particularly high genetic diversity. The greatest species diversity occurs in Borneo, mainly in western
Kalimantan and Sarawak where 26 species, six varieties and six natural hybrid combinations are known
followed by Sumatra (Sumatera) with 16 species, three varieties and four natural hybrid combinations
and Sri Lanka with ten species and one natural hybrid combination. This contrasts with Indochina with
only seven species, but nine varieties, as well as with New Guinea with two species and two varieties,
however taxonomic work is showing that there are new taxa to be described in a number of areas. This
diversity is reflected in the distribution of widespread taxa, as compared to local endemics. Areas such
as western India and Indochina support a higher proportion of widespread taxa, whereas Borneo and
Sumatra support high proportions of local endemics.
Throughout their range, Cryptocoryne taxa are mainly threatened by six types of action: clearance of
natural habitats, agricultural intensification (often gradually following on from selective logging of
natural forest and then small-scale clearance), development, uncontrolled and/or illegal collection,
hydrological modification and water use (abstraction). The most significant threat to Cryptocoryne
populations throughout their range is the degradation of habitats within which wetlands supporting
Cryptocoryne populations occur and their conversion to industrial-scale plantations. However the
relationship between habitat degradation and the survival of some Cryptocoryne populations is not
simple. Many Cryptocoryne populations appear able to survive some aspects of the conversion of forest
to industrial-scale plantations, small-holder farming and even urbanisation, with populations persisting
in drainage ditches in highly modified landscapes, such as in northern Kerala in western India. However,
these are likely to be sparse remnants of formerly larger and more extensive populations.
This Conservation Action Plan is based on preparation of Red List assessments, employing the IUCN
Criteria, for all species, varieties and hybrid combinations known at the time or preparation. Assessments
of species and varieties were submitted for publication in 2022. The information included in these
assessments was then compiled to enable analysis of threats, leading to development of a suite of
proposals for conservation action for species or regional populations. The action plan is presented in the
following sections:
An introduction to the Conservation Action Plan.
A summary characterisation of the genus Cryptocoryne.
An overview of the conservation status of all known taxa, based on Red List assessments.
Analysis of the threats affecting Cryptocoryne populations.
A strategic plan presenting an overview of potential action at a range of levels down to individual
regions and taxa.
A list of references used in putting together the Action Plan.
An appendix presenting the threat status assigned to each taxon assessed.
