Journal of Threatened
Taxa | www.threatenedtaxa.org | 26 January 2025 | 17(1): 26394–26400
ISSN 0974-7907 (Online)
| ISSN 0974-7893 (Print)
https://doi.org/10.11609/jott.9253.17.1.26394-26400
#9253 | Received 30 June
2024 | Final received 11 December 2024 | Finally accepted 17 December 2024
Assessing
the conservation status of Elaphoglossum stigmatolepis (Fee) T.Moore (Dryopteridaceae),
an endemic fern in the Western Ghats of India
A. Benniamin 1 , Sakshi Pandey 2 & Rajat Mondal
3
1,2,3 Botanical Survey of
India, Western Regional Centre, 7, Koregaon Road,
Pune, Maharashtra 411001, India.
1 fernsbenni@gmail.com
(corresponding author), 2 sakshipecc.30@gmail.com, 3 rmbotany@gmail.com
Editor: Aparna Watve,
Biome Conservation Foundation, Pune, India. Date of publication: 26 January 2025
(online & print)
Citation: Benniamin, A., S. Pandey & R. Mondal (2025). Assessing the conservation status of Elaphoglossum stigmatolepis
(Fee) T.Moore (Dryopteridaceae), an endemic fern in the Western Ghats of
India. Journal of Threatened Taxa 17(1):
26394–26400. https://doi.org/10.11609/jott.9253.17.1.26394-26400
Copyright: © Benniamin et al. 2025. Creative Commons
Attribution 4.0 International License. JoTT allows
unrestricted use, reproduction, and distribution of this article in any medium
by providing adequate credit to the author(s) and the source of publication.
Funding: Ministry of Environment, Forest and Climate Change, New Delhi.
Competing interests: The authors declare no competing interests.
Author details: Dr. A. Benniamin, scientist ‘F’ and head of the Botanical Survey of India, Western Regional Centre, Pune, is a distinguished researcher in the field of pteridophytes.He is also an Asia member of the IUCN SSC Group and a fellow of the Linnean Society, London. His research focuses on the taxonomy of pteridophytes, conservation of pteridophytes through tissue culture, and their IUCN assessment. Sakshi Pandey is working as a junior
research fellow at the Botanical Survey of India. As an IUCN Species Information Service
(SIS) assessor, she plays a role in documenting and assessing species, and her five research papers reflect her dedication to scientific inquiry in this field. Rajat Mondal is working as a junior research fellow at the Botanical Survey of India, Western Regional Centre, Pune. He is an IUCN Species Information Service
(SIS) assessor and has published four research papers to his credit.
Author contributions: AB conducted the field surveys, analyzed the data, provided photographs, location details, and revised the initial draft. SP conceived and designed the study and authored the initial draft of the manuscript. RM contributed to data interpretation. All three authors reviewed and approved the final manuscript.
Acknowledgements:
The authors are thankful to Dr. A.A. Mao, director, Botanical Survey of India, Kolkata, and head of the office of BSI WRC, Pune for their support and encouragement. I also want to thank Karnataka State Forest PCCF for granting permission for the field survey.
Two of the authors, Pandey & Mondal, are thankful to the Ministry of Environment, Forest and Climate Change, New Delhi for providing financial support in the form of JRF under flora of India Project for this research work.
Abstract: Elaphoglossum stigmatolepis, a fern species
endemic to the semi-evergreen or evergreen forests of the Western Ghats of
India, has recently garnered attention due to its precarious status within its
native habitat. Thriving within the unique microclimates of these regions, this
fern has been assessed for the first time. The results of this assessment are
concerning, as the species has been classified as Endangered under the IUCN Red
List Categories and Criteria 3.1. The limited population of E. stigmatolepis underscores its vulnerability,
highlighting the pressing need for dedicated conservation efforts. This
assessment represents a pivotal step in acknowledging and addressing the
threats faced by E. stigmatolepis, emphasizing
the urgency of implementing measures to ensure its survival and safeguarding
the biodiversity of the Western Ghats.
Keywords: Biodiversity,
endangered, epiphyte, GeoCAT, habitat, holodimorphic, population, species information assessment
(SIS), survival, threat.
INTRODUCTION
The Elaphoglossum
genus, originating from Schott’s initial description and later revised by John
Smith, stands as one of the most diverse genera within the fern family,
boasting around 600 species. Interestingly, the bulk of these species find
their home in the New World. According to the Pteridophyte Phylogeny Group I
(PPG I) classification, this species belongs to the family Dryopteridaceae.
Approximately, 13 species of Elaphoglossum
inhabit India (Fraser-Jenkins et al. 2021). Among all the above species E. beddomei Sledge, E. nilgiricum
Krajina ex. Sledge, and E. stigmatolepis (Fee)
Moore are endemic to the southern Western Ghats. Madhusoodanan
(2015) observed only two species—E. nilgiricum
and E. beddomei- in Kerala. Rajagopal &
Bhat (1998) reported the presence of only E. nilgiricum,
while a more recent study by Tripathi et al. (2016) confirmed the existence of E.
stigmatolepis in Karnataka and Tamil Nadu
(Manickam & Irudayaraj 2003). The species’ distribution is
restricted to a few specific localities within these states, making it
susceptible to habitat fragmentation and other environmental threats.
The present study aimed to
assess the status of E. stigmatolepis using
the IUCN Red List Categories and Criteria which involves a thorough analysis of
the species’ extent of occurrence (EOO) and area of occupancy (AOO) from field
data and secondary sources. This evaluation is crucial for understanding the
conservation needs of this species and formulating effective strategies to
ensure its continued survival amidst the growing threats of habitat degradation
and climate change in the Western Ghats. In some earlier assessments of E. stigmatolepis it was considered as ‘rare’ even though
some effective attempts were made by the authors Chandra et al. (2008), Ebihara et al. (2012), Fraser-Jenkins (2012), and Benniamin et al. (2021); it may not be fully in
accordance with the IUCN criteria.
Through rigorous
scientific investigation and proactive conservation measures, the goal is to
mitigate the risks facing this unique and ecologically significant fern
species, safeguarding its presence for future generations and preserving the
rich biodiversity of the Western Ghats ecosystem. The work also forms a
baseline for ecologists, conservation biologists, and applied researchers for
conservation and sustainable utilization of the species.
METHODS
Study area
The study focused on
the Western Ghats in general with particular reference to Kudremukh
National Park, located in the Chikkamagalur District
of Karnataka (13.0169–13.4880 N & 75.1527–75.4169 E). Among various sites
within the park, Kadambi Falls was selected as a key
location for its rich biodiversity. At this site, researchers found and
collected a specimen of E. stigmatolepis, a
rare epiphytic fern, growing exclusively on a Memecylon
tree. This fern, observed in a single patch on the tree, highlights the park’s
unique and diverse plant life.
Methodology
Extensive field
exploration formed the cornerstone of the data collection process. Geographical
coordinates were meticulously recorded using a geographical positioning system
(GPS) during field expeditions to capture accurate location data of E. stigmatolepis populations. These field excursions
provided us with primary data crucial for understanding the distribution and
habitat preferences of the species. Supplementing our primary data collection
efforts, secondary data were gathered from various herbaria such as the Central
National Herbarium (CNH) Botanical Survey of India, Western Regional Centre
(BSI), and digital herbaria namely Flora of Peninsular India, Digital Flora of
Karnataka, CALI (Calicut University Herbarium) & XCH (St. Xavier’s College,
Palayamkottai). Additionally, a preliminary search in
the GBIF showed some odd and wrong records under the name ‘E. stigmatolepis’ from Reunion (Africa), and iNaturalist (2024) which yielded results with zero
observation. The reviewed published literature further enriched the
understanding of the geographic locations of Benniamin
et al. (2020, 2021), Rajagopal & Bhat (1998), Manickam &
Irudayaraj (2003), and ecological characteristics of E. stigmatolepis.
To systematically organize the compiled data, essential parameters such as
distribution, localities, state, collector names, date of collection, basis of
record, altitude, latitude, longitude, and habitat were recorded in an Excel
spreadsheet (Table 1). Subsequently, this data was imported and processed for
analysis. Utilizing open-source online software, specifically the Geospatial
Conservation Assessment Tool (GeoCAT) developed by Bachman
et al. (2011), available at http://geocat.iucnredlist.org
(Image 1). The area of occupancy (AOO) and extent of occurrence (EOO) values
were calculated based on the recorded location points. These metrics provided
crucial insights into the spatial distribution and extent of the species’
range. To ensure comprehensive documentation of the findings, the Species
Information Service (SIS) portal was utilized to detail various aspects of E.
stigmatolepis, including species attributes,
geographic range, AOO, EOO, number of locations, elevation occurrence,
population information, habitat and ecology, threats, conservation strategies,
ecosystem services, and Red List assessment. By employing a multidimensional
approach encompassing fieldwork, data synthesis from diverse sources, and
advanced analytical tools, the methodology aimed to provide a robust assessment
of the threatened status of E. stigmatolepis.
This systematic methodology lays the foundation for informed conservation
strategies tailored to safeguarding this endemic fern species and its fragile
habitat in the Western Ghats ecosystem.
RESULTS
Elaphoglossum stigmatolepis (Fee) T.Moore,
Index Fil. 16. 1857; Sledge in Bull. Brit. Mus. (Nat. Hist).
Bot. 4: 86. 1967; Nayar & Kaur, Comp. Bedd. Hand., 97. 1974; Dixit, Census 166. 1984; Manickam
& Irudayaraj Pterid. Fl. West. Ghats 287. 1992. Acrostichum stigmatolepis
Fee, Mem. Fam. Foug. 2: 62 t. 24 f. 2. 1845. Elaphoglossum conforme
sensu Bedd. FSI 67 t. 198
(1864) & Handb. 416 t. 247 (1883) pro parte (non J. Sm.). Acrostichum
conforme sensu Clarke
in Trans. Linn. Soc. London II Bot. 1: 576. 1880 pro parte.
Elaphoglossum ballardianum
K. Biswas in Bull. Misc. Inf. Kew. 1939: 239. 1939.
Rhizome
long creeping, 3–4 mm thick, densely scaly; scales ovate-lanceolate, attenuate,
brown at the base, blackish-brown above. Stipes scattered, deep brown, 8–11 cm
long. Lamina simple, dark green, lanceolate, 8–18 cm long, 1.5–2.0 cm
wide, apex acute. The upper and lower halves of the lamina gradually
narrowed, with an entire margin with a cartilaginous border. The midrib is
slightly raised on both sides and shallowly grooved above; veins immersed; the
underside of the lamina and midrib covered by minute, fimbriate scales. Fertile
fronds approximately 12–14 cm long and 1–1.5 cm wide, oblanceolate, much
compressed, with a moderately longer stipe and revolute margin. Sori acrostichoid; spores
monolete, reniform, dark brown (Image 2).
Habitat and Ecology: It is an epiphytic fern thriving in the
semi-evergreen and evergreen forests that characterize this region. It
typically grows on tree trunks under the dense forest canopy, which provides
the shaded, humid environment essential for its survival. This fern prefers
elevations ranging 1,000–2,650 m, where the cool, moist conditions of the
montane regions are ideal for its growth.
Specimen examined: Karnataka, Kadambi
Falls, Kudremukh National Park, 24.xi.2015, coll.
Devendra Tripathi, 197952, BSI (Image 3).
Distribution: Tamil Nadu and Karnataka. Endemic to
southern India.
DISCUSSION
Elaphoglossum stigmatolepis is placed under the Endangered (EN) category
in the present assessment as the species is restricted to only two states in
India, i.e., Karnataka and Tamil Nadu. The EOO for the species was estimated to
be 7,808.857 km2 which is more than the threshold value for the
Endangered category, so it’s not applicable for category assignment. The AOO
was calculated based on the cell size of (2 × 2 km) recommended by IUCN and it
was estimated to be 32 km2 which meets criterion B2 for the
Endangered category. Field experiences and data collected from secondary
sources indicate that the species is reported from five localities, namely,
Palani Hills, Nilgiris, Anamalais
Hills, Kodaikanal (Gundar
Shola) in Tamil Nadu, and Kadambi Falls in Kudremukh National Park, Karnataka, this aligns with
sub-criterion ‘a’ for the endangered category, as the number of locations are
five.
The species is facing multiple threats across
its distribution range, leading to a continuous decline in habitat quality and
population size. In Kudremukha National Park,
infrastructure development such as road construction and increased tourism
activities have further degraded its habitat. Additionally, invasive plant
species like Lantana camara and Chromolaena odorata
are outcompeting native vegetation, reducing the availability of suitable
microhabitats. The climate crisis exacerbates the situation by altering
rainfall patterns and microclimatic conditions essential for the species’
growth and reproduction. Intrinsic factors, such as poor spore viability, low
germination rates, and limited genetic diversity due to declining population
size, further jeopardize its survival. These cumulative threats not only reduce
the extent of suitable habitat but also impact the species’ ability to
regenerate, qualifying it for listing under the Endangered category based on
sub-criterion ‘b (iii)’.
Among seven species of Elaphoglossum
in India, only E. stigmatolepis and E. stelligerum are with holodimorphic
fronds and the remaining five species are with weak or hemidimorphic
fronds. It is possible that the relative costs of this reproductive system are
offset by increased spore dispersal (Watkins et al. 2016). Most of the species
in the related lomariopsidoid genus Bolbitis are with strictly holodimorphic fronds (Hennipman
1977). In general, frond dimorphism may influence the reproductive
successfulness of that particular fern, at least to some extent by the production
of a low number of spores which may be released within a short span of time
this might be the reason for continuous reduction in a number of mature
individuals which qualify the species for the Endangered category under
sub-criteria ‘b (v)’.
In Kudremukh National Park, the primary threats to Elaphoglossum stigmatolepis
include habitat loss due to deforestation for agricultural expansion and tree
cutting, which significantly impacts its association with Memecylon
species. Increased infrastructure development, such as road construction, has
fragmented the habitat, isolating subpopulations and limiting dispersal. In Nilgiris,
tourism-related activities, including trekking and recreational pursuits, lead
to habitat disturbances like soil compaction and trampling, which degrade the
forest floor and reduce the availability of suitable microhabitats. In Kodaikanal hills, the conversion of forested areas into
plantations has caused severe habitat modification and population declines.
Across these locations, climate change intensifies these issues, with altered
rainfall patterns and rising temperatures further reducing habitat quality and
the species’ ability to regenerate. These localized threats collectively
contribute to a decline in both the extent of habitat and the size of
subpopulations, justifying its endangered status.
Elaphoglossum stigmatolepis, an endemic fern of
the Western Ghats, is reported from Karnataka and Tamil Nadu with an EOO of
7808.857 km² and an AOO of only 32 km², calculated using GeoCAT
and a 2 × 2 km grid. The species is restricted to five locations, with a
reported continuous decline in the number of locations, mature individuals, and
habitat quality due to threats such as deforestation, road expansion, urbanization,
and other anthropogenic pressures. The limited AOO, small number of locations,
and ongoing decline in population and habitat quality justify its assessment as
Endangered under the IUCN Red List criterion B2ab(iii,v).
In light of these findings, a comprehensive
conservation strategy for the endangered endemic fern E. stigmatolepis,
utilizing both in vivo and in vitro methods is strongly recommended. Existing
research, such as studies by Johnson et al. (2015) and Johnson & Shibila (2018), highlights the potential of in vitro spore
culture. Effective conservation strategies should include habitat protection,
ecological restoration, continuous monitoring, community engagement, and
climate change adaptation efforts. Addressing these diverse challenges is essential
to safeguarding E. stigmatolepis and securing
the long-term survival of this unique fern species in the Western Ghats.
Table 1.
Distribution of Elaphoglossum stigmatolepis in the Western Ghats.
|
|
Basis of records |
Collection no. |
Collection date |
Altitude (m) |
Name of collectors |
State |
Locality |
Habitat |
Data source |
|
1 |
Preserved specimen |
197952 |
24.xi.2015 |
1,350 |
Deventra Tripathi & A. Benniamin |
Karnataka |
Kudremukha National Park, Kadambi Falls. |
Epiphyte
exclusively on Memecylon tree (one patch). |
BSI (Botanical
Survey of India, Western Regional Centre) Pune. |
|
2 |
Preserved specimen |
RHT 32615 |
02.v.85 |
2,200 |
VSM & KMM |
Tamil Nadu |
Madurai (Anna), Kodaikanal, Palni Hills, Gundar Shola. |
Epiphyte. |
XCH (St. Xavier’s
College, Palayamkottai). |
|
3 |
Preserved specimen |
RHT 34438 |
16.ii.86 |
1,850 |
VSM & KMM |
Tamil Nadu |
Coimbatore, Valparai, Anaimalai Hills,
Grass Hill- Periyar Path. |
Epiphyte on forest
trees. |
XCH (St. Xavier’s
College, Palayamkottai). |
|
4 |
Preserved specimen |
XCH 410 (2) |
24.x.91 |
2,650 |
VSM |
Tamil Nadu |
Nilgiri, Dodabetta Road. |
Occasional epiphyte
in the forest interior. |
XCH (St. Xavier’s
College, Palayamkottai). |
|
5 |
Preserved specimen |
XCH 436 |
24.x.91 |
2,650 |
VSM |
Tamil Nadu |
Nilgiri, Dodabetta Road. |
Rare epiphyte
locally abundant in shola interior. |
XCH (St. Xavier’s
College, Palayamkottai). |
|
6 |
Preserved specimen |
XCH 456 |
25.x.91 |
2,200 |
VSM |
Tamil Nadu |
Nilgiri, Forest Bungalow
of Terrace Estate. |
Epiphyte,
occasional and locally abundant. |
XCH (St. Xavier’s
College, Palayamkottai). |
|
7 |
Preserved specimen |
XCH 568 |
27.x.91 |
2,300 |
VSM |
Tamil Nadu |
Nilgiri, Sholas Between
T.R. Bazaar And Belluve. |
Epiphyte. Rare. |
XCH (St. Xavier’s
College, Palayamkottai). |
|
8 |
Preserved specimen |
XCH 583 |
28.x.91 |
2,300 |
VSM |
Tamil Nadu |
Nilgiri, Shola On The Short Cut From The T.R. Bazaar To Naduvattum. |
Occasional
epiphyte. Sterile. |
XCH (St. Xavier’s
College, Palayamkottai). |
|
9 |
Preserved specimen |
XCH 855 |
06.xii.91 |
2,100 |
VSM |
Tamil Nadu |
Nilgiri, Avalanchi Forest. |
Epiphyte in shola;
rare. |
XCH (St. Xavier’s
College, Palayamkottai). |
|
10 |
Preserved specimen |
XCH 900 (2) |
07.xii.91 |
2,100 |
VSM |
Tamil Nadu |
Nilgiri, Avalanchi Forest. |
Rare, in the forest
interior; sterile. |
XCH (St. Xavier’s
College, Palayamkottai). |
|
11 |
Preserved specimen |
XCH 933 |
08.xii.91 |
2,200 |
VSM |
Tamil Nadu |
Nilgiri, Round Road on the
Plateau, Upper Bhavani (Manjoor). |
Rare, epiphyte in
the shola. |
XCH (St. Xavier’s
College, Palayamkottai). |
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