Abatia mantiqueirensis Nepom., 2024

Nepomuceno, Álvaro, Domínguez, Yoannis, Negrão, Raquel, Amaral, Renara Nichio, Dutra, Valquíria Ferreira & Alves-Araújo, Anderson, 2024, New species of Salicaceae with opposite leaves from the Atlantic Forest, Brazil, Phytotaxa 662 (2), pp. 150-160 : 152-157

Abatia mantiqueirensis Nepom. , spec.nov. Fig. 1

Type:— BRAZIL. Minas Gerais: Delfim Moreira, Fazenda Boa Esperança, Trilha dos Romeiros, 22º35’02’’S, 45º19’03’’W, 1616 m elev., 19 March 2011, L. L. Giacomin et al. 1485 (fl., fr.) (holotype: BHCB!, isotypes: RB!).

Abatia mantiqueirensis is morphologically similar to A. americana by presenting one of the largest leaves of the genus measuring 7–20 × 8–10 cm (vs. median leaves measuring 4–12(–15) × 3–6(–7) cm), a margin with acute serrations (vs. margin with rounded serrations), rounded to concave glands at the apex of the margin serrations projected outside the leaf blade (vs. non-concave curved glands at the apex of the margin serrations inserted into the leaf blade), canaliculated petiole (vs. non-canaliculate petiole), articulated pedicel winged in the upper portion (vs. articulated pedicel without winged in the upper portion), glands absent on the petiole and pedicel (vs. glands present on the petiole and pedicel) and seeds with tiny dorsal wings (vs. seeds without dorsal wings).

Small tree, ca. 5–7 m tall, branches with simple, pubescent, light brown trichomes. Stipules absent. Leaves simple, opposite, petiolate, petioles 2–6 cm long, puberulent to tomentose, canaliculate; leaf blade 7–20 × 8–10 cm, chartaceous, elliptical to lanceolate, apex acute, base attenuated to rarely slightly rounded, margin ciliate, serrate, acute serrations with rounded to concave glands at the apex projected outside the blade, both surfaces with simple and golden trichomes dispersed throughout the blade with higher concentration of them on the primary and secondary veins, brochidodromous, secondary venation 8–13 pairs, opposite at the base, usually up to the fourth pair, alternating in the remaining pairs, prominent on the lower leaf surface, flat on the upper leaf surface, punctuations and translucent lines absent. Inflorescence racemous, terminal or axillary, peduncle 6–7 cm long, cylindrical, pilose, rachis 12–25 cm long, cylindrical, hirsute; bracteoles lanceolate, pilose; flower buds acute; flowers yellow, monochlamydeous, pedicellate, pedicel 3–6 mm long, persistent on the rachis, articulated in the median region, lower portion densely pilose, glands absent, upper portion pilose to glabrescent, winged; sepals 4.3–5 × 2–3 mm, yellow, lanceolate, trinervate, glabrous on the inner side, pilose on the outer side, persistent in the capsule; stamens with yellow filaments and anthers, numerous, persistent, forming a bundle, filaments 3–5 mm long, glabrous, anthers oblong, glabrous, dorsifixed; ovary 1–3 × 0.5–1 mm, yellow, ovate, hirsute, slightly furrowed, style 2–3 mm long, yellow, glabrous, persistent, stigma yellow, capitate and glabrous. Capsules septicide 4–5 × 3–4 mm, oblongoid to ovoid, slightly grooved, dividing into two parts, each part with two valves, glabrescent. Seeds>10, 1–2 × 0.5 mm, oblongoid to polyhedral, glabrous, foveolate, light brown with tiny hyaline dorsal wings.

Etymology:—The specific epithet refers to the Mantiqueira Montain Range, where the species was collected and comprises an important center of endemism, conservation and biodiversity in the Brazilian Atlantic Forest ( Costa & Herrmann 2006).

Paratypes:— Brazil, Minas Gerais: Caldas (old Parreiras), 08 November 1940, Mello Barreto 11075 (fl., fr.) ( BHCB!, BHMH!) ; Delfim Moreira, Fazenda do Onça , 22º36’32’’S 45º20’47’’W, 1648 m elev., 14 March 2011, T. E. Almeida et al. 2805 (fl., fr.) ( BHCB!, RB!) ; Itamonte, Parque Nacional do Itatiaia , 18 February 2017, N. S. Streher & P. J. Bergamo 43 (fl.) ( UEC!) ; 21 January 2020, D. Nunes et al. 305 (fl.) ( RB!, SPF!) ; Poços de Caldas , 14 January 1965, O. Leoncini 470 (fl.) ( R!) ; 12 February 1965, M. Emmerich 2386 (fl., fr.) ( R!). Rio de Janeiro: Resende, Engenheiro Passos, Parque Nacional do Itatiaia , 1800 m elev., 22 January 2023, V. F. Mansano et al. 180 (fl.) ( IAC!, RB!) ; Itatiaia, Parque Nacional do Itatiaia, 22º22’02’’ S, 44º41’23’’ W, 1000m elev., 08 December 2019, J. Külkamp et al. 1116 (fl.) ( HUEFS!, RB!, SP!) ; 17 January 1979, P. Occhioni 8738 (fl.) ( MBM!) ; 26 January 1975, G. Hatschbach et al. 35855 (fl.) ( MBM!) ; 15 February 1995, J. M. A. Braga et al. 2081 (fl., fr.) ( RB!) ; 09 January 1943, J. J. Sampaio 1059 (fl.) ( RB!) ; 02 December 1997, J. M. A. Braga et al. 4462 (fl.) ( RB!) ; February 1894, E. H. G. Ule 80 (fl., fr.) ( R!) ; 14 January 1961, M. Emmerich & A. G. Andrade 602 (fl.) ( R!) .

Phenology:—Flowers and fruits were observed from November to March. Abatia mantiqueirensis is a species with simultaneous flowering and fruiting.

Notes:— Abatia mantiqueirensis is morphologically similar to A. americana (Gardner) Eichler (1871:510) , one of the most widely distributed species of the genus in Brazil. Morphological features such as the serration on the leaf margin and curved glands not projected outside the leaf blade, non-canaliculated petiole with glands at the apex, close to the base of the leaf blade, pedicel with glands, not winged, with articulation close to the base are the main morphological characteristics of A. americana that differentiate this species from A. mantiqueirensis . Furthermore, A. mantiqueirensis differs from other Brazilian species such as A. microphylla Taubert (1892:11) and A. glabra Sleumer (1980: 49) by yellow petioles (vs. reddish petioles) in fresh material, and A. angeliana M.H. Alford (2006: 296) by having leaf blade chartaceous, peninnerve veins and flowers with staminodes (vs. leaf blade membranaceous, 3–5 nerves at the base and flowers without staminodes).

Abatia americana has attractive numerous golden to yellow flowers on terminal inflorescences and is one of the most common species in Brazil for the genus and the most collected, especially in the high-altitude fields of the Atlantic Forest. Abatia americana shows phenotipic plasticity across its range, especially when comparing specimens found in the Serra dos Órgãos region, in Rio de Janeiro, Serra da Mantiqueira, in the division among the states of São Paulo, Minas Gerais and Rio de Janeiro, Caparaó National Park, in the Division of the states of Minas Gerais and Espírito Santo, and the “ Campos rupestres ” in the region of Ouro Preto, Minas Gerais. In herbaria collections, it is common to observe morphological divergence inside specimens identified as A. americana . Among the morphological characters with the greatest divergence among the specimens, the dimensions, type and density of trichomes on the leaf blade, the shape of the leaf margin, as well as the glands, and the articulation of the pedicel and morphology of the floral bud stand out.

Distribution and Habitat:—So far, Abatia mantiqueirensis is only known from three populations ( Fig. 2 ) located in the Mantiqueira Mountain Range (“Serra da Mantiqueira”). The first one is located in the Delfim Moreira region, in Minas Gerais, where the species is found in the areas of two eco-lodges, Hotel Fazenda Boa Esperança (typus locality) and Fazenda do Onça, being subject to the pressures of ecotourism practices. The second population occurs in a forest fragment close to the urban area of the municipality of Caldas, also in Minas Gerais, facing pressures from ecotourism and, in this case, associated with agricultural fragmentation. The third population is located in the Itatiaia National Park, between the states of Minas Gerais and Rio de Janeiro, this being the only population protected by legislative instruments as the area is an integral conservation unit.

Covering approximately 130,000 km 2, the Mantiqueira Montain Range encompasses the states of Espírito Santo, Minas Gerais, Rio de Janeiro and São Paulo, and is located in the Atlantic Forest of southeastern Brazil ( Cruz & Feio 2007; Silva et al. 2018), however, there are some geographically more restricted delimitations, not including Espírito Santo. The region is characterized by significant altitudinal variation with several points recognized as “ campos de altitude ”, one of the phytophysiognomies of the Atlantic Forest. Examples include the Pico da Bandeira (2897 m elev.), Pedra da Mina (2798 m elev.), Pico das Agulhas Negras (2791 m elev.), Morro do Couto (2680 m elev.), Pedra do Sino de Itatiaia (2670 m elev.) and Pico dos Três Estados (2665 m elev.) which are considered the highest points in the Mantiqueira Montain Range ( Peixoto et al. 2020). Furthermore, the region hosts seasonal forests and rainforests, as well as ecotone areas. Geologically, it is composed of pre-Silurian gneiss and granite, together with a disjoint layer of different types of rocks, in predominantly granitic and metamorphic soils, in addition to small alluvial stretches ( Gatto et al. 1983; Benites et al. 2007). The predominant climate is classified as humid subtropical, with dry winters and mild summers (Cwb) ( Alvares et al. 2013).

These climatic, geological and environmental conditions found in the Mantiqueira Mountain Range seem to influence the distribution of the species, since, like other species of the genus in Brazil, Abatia mantiqueirensis is endemic to the Brazilian Atlantic Forest, with the exception of A. americana , which is also found in the “ campos rupestres ” of the Cerrado. Overall, Abatia species are recorded at high altitudes, often above 1,000 m elev., in open areas or on the edges of forest fragments.

Potential distribution for the present and future:—The modeled potential geographic distribution of Abatia mantiqueirensis for the present and future climatic scenarios ( Fig. 3a–b ) partially agrees with the current known range of the species. Habitat suitability areas, especially the ones with higher suitability, appeared concentrated in the Mantiqueira Montain Range. The regions of maximum suitability correspond to two protected area, the Itatiaia National Park and the Serra do Papagaio State Park, in Minas Gerais. To date, there are no reports of records of the species for the second protected area, however, it may probably be suitable for the occurrence of A. mantiqueirensis due to the environmental conditions. Furthermore, collection efforts need to be carried out to expand knowledge about the populations, as well as possible expansion of the geographic distribution and environmental adaptability, especially in the Mantiqueira Montain Range, from Campos do Jordão State Park in São Paulo, to the aforementioned protected area. The environmental variable ‘precipitation of the warmest quarter’ (bio18) had the greatest contribution (59.6%) to the model, followed by the ‘minimum temperature of the coldest month’ (bio6, 13.5%), the ‘precipitation of the coldest quarter’ (bio19, 13.1%), the altitude (7%) and the ‘precipitation of the driest month’ (bio14, 6.8%) ( Table 1). The accuracy of the modeled geographical extent was better than random based on the two assessed metrics ( AUC =0.952 and TSS=0.991).

For the future projections, in the SSP1–2.6 environmental scenario ( Fig. 3c ), medium suitability areas showed larger geographic range, especially in Minas Gerais, where they also reach areas with Cerrado biome vegetation. Furthermore, areas with similar suitability were also identified in the states of Rio de Janeiro and São Paulo, in the Serra do Mar Mountain Range along the coast. Areas with lowest suitability also occur in ecotonal areas between the biomes Cerrado and Caatinga in the north of Minas Gerais, between the Atlantic Forest and Cerrado in São Paulo and Mato Grosso do Sul, in addition to the Atlantic Forest in the states of Paraná, Santa Catarina and Rio Grande do Sul. Finally, the areas of highest suitability were identified in the Mantiqueira Montain Range, between the Campos do Jordão and Serra do Papagaio State Parks and Itatiaia National Park.

For the SSP2–4.5 and SSP3–7.0 scenarios ( Figs. 3d–e ), a reduction of suitable areas was observed, especially in Minas Gerais. The areas of highest suitability appeared restricted to the extreme north of the species known range, that is, the Itatiaia National Park. However, for the SSP3–7.0 scenario, a region of highest suitability was also identified in the state of Paraná, specifically in the coastal region that comprises three protected area, the Bom Jesus Biological Reserve, the Guaraqueçaba Environmental Protection Area and the Superagui National Park. There is no record of the species for this region which comprises the Serra do Mar vegetation complex of the Atlantic Forest under direct influence of climate variations that are most evident on the coast ( Sanchez et al. 2013). Finally, in the SSP5–8.5 scenario ( Fig. 3f ), the areas of medium and higher suitability appeared restricted to the states of Minas Gerais, Rio de Janeiro and São Paulo, that comprise the Mantiqueira Mountain Range region showing the highest suitability for the species.Additionally, for this scenario’s projection the ecotonal areas between the Atlantic Forest and other biomes are practically negligible, with the most relevant suitable habitats being restricted to the Atlantic Forest.

According to the Intergovernmental Panel on Climate Change (2022), the SSP2–4.5 scenario is the most likely to occur, thus, we hypothesize that the population located at the Itatiaia National Park and the surrounding areas is the most likely to survive, as evidenced in the habitat suitability analyses, also because it is located within an environmentally protected region. Therefore, this population should not be impacted by agriculture, monoculture and illegal deforestation practices. Nonetheless, it is still necessary to be aware of the impacts caused by ecotourism within conservation units, since the species occur as scattered individual on the edges of trails and is susceptible to be impacted by the movement of tourists during the trail journey, as well as the maintenance of the trails carried out by the staff of the conservation units.

Conservation:— Abatia mantiqueirensis is a small tree, endemic to southeastern Brazil with known distribution restricted to the states of Minas Gerais and Rio de Janeiro occurying as three subpopulations on the edge of forest fragments along the Mantiqueira Mountain Range. It presents an estimated extension of occurrence ( EOO) of 3,971 km 2, an area of occupancy ( AOO) of 20 km 2, and three locations subject to threats (locations = 3). Thus, it reaches the thresholds of the Endangered ( EN) category, according to criterion B ( IUCN 2012, 2022). A continued decline in habitat extension and quality is inferred based on observed local threats, highlighting the fragmentation and degradation of habitat caused by the opening and expansion of trails for ecotourism, cattle raising, and agricultural expansion with the consequent invasion of ruderal species in anthropisized areas (Hotel Fazenda Boa Esperança and Fazenda do Onça). In addition, urban expansion, especially for the subpopulation of Caldas where the species occurs in a fragment close to the urban area, also can represent an important threat. On the other hand, the population that occurs within the Itatiaia National Park is likely to be protected.

There is no available information on population decline, therefore, thresholds for a risk category according to criterion A were not assessed. The species meets all the thresholds and requirements necessary to be evaluated as Endangered ( EN) based on criterion B; however, to date, few individuals are known, and they have only been recorded on the edges of forest fragments and trails. Therefore, considering that it has less than 50 mature individuals, the species is assessed here as Critically Endangered ( CR) according to the C 2a(i)+ D criteria. Research actions are necessary to search for more refined information on population size and trends and its habitats, as well as actions for the conservation of known populations, especially in unprotected areas, where the species still lacks in situ and/or ex situ conservation initiatives.

High altitudes areas function as one of the environmental drivers of biological speciation as they can support ecological and environmental refuges for populations of different taxa ( Silveira et al. 2020). Gene flow between plant and animal’s populations occurying in these environments is difficulted due to geographic, environmental and ecological barriers ( Pearson, 2006). These factors contribute to the high endemism found in high altitude regions, leading to the establishment of micro-endemic taxa that often appear to scientific knowledge already threatened with extinction ( Azevedo et al. 2024). Furthermore, the climatic conditions of these environments, including atmospheric and geomorphological factors, are unique and fundamental for the preservation of functional biological traits existing in ecological refuges at high altitudes, such as the opposite leaves in Salicaceae in Neotropical region, as well as for biodiversity conservation overall ( Grabherr et al. 1994; Silveira et al. 2020).

Rates of global warming have been shown to be more pronounced at higher altitudes, which could potentially accelerate the rate of change in hydrological regimes, particularly precipitation and underground storage, affecting the biodiversity of tropical mountainous ecosystems ( Pepin et al. 2015). Species in mountainous habitats are the most vulnerable to climate change, as variations in temperature and rainfall rates can cause extinction or drastic population reduction, since these species are often endemic and occur isolated in specific habitats ( Pickering et al. 2008; Gottfried et al. 2012; Leão et al. 2014; Wehn et al. 2014).

Figures

FIGURE 1. Abatia mantiqueirensis. a. Floral branch. b. Lower leaf surface. c. Upper leaf surface. d. Leaf basis and petiole canaliculate. e. Leaf margin. f. Detail of leaf margin. g. Detail of gland on the leaf margin. h. Flowers in the inflorescence. i. Flower showing the outer surface of the sepal with three veins. j. Flowers showing the inner surface of the sepal. k. Gynoecium. l. Capsule opening with persistent stamens. m. Capsule opening with persistent sepals. n. Detail of the winged pedicel. o. Seed ventral surface. p. Seed dorsal surface.

FIGURE 2. Geographical distribution of Abatia mantiqueirensis. States of Brazil: ES—Espírito Santo, MG—Minas Gerais, RJ—Rio de Janeiro and SP—São Paulo.

FIGURE 3. Potential distribution of Abatia mantiqueirensis. A. Present. B. Focusing in Present. C. Future—SSP1–2.6. D. Future— SSP2–4.5. E. Future—SSP3–7.0. F. Future—SSP5–8.5.