Nowhere to escape – Diversity and community composition of ferns and lycophytes on the highest mountain in Honduras

IPCC predictions for Honduras indicate that temperature will increase by up to 3–6°C and precipitation will decrease by up to 7–13% by the year 2050. To better understand how fern and lycophyte communities might be affected by climate change, we comprehensively surveyed the community compositions of ferns and lycophytes at Celaque National Park, the highest mountain in Honduras. We surveyed a total of 80 20 × 20 m2 plots along an altitudinal gradient of 1249–2844 m a.s.l., identifying all species and estimating their abundances. We recorded a total of 11,098 individuals from 160 species and 61 genera. Community composition was strongly influenced by changes in altitude, precipitation and the abundance of bryophytes (a proxy for air humidity). Of the 160 species, 63 are expected, under a RCP2.6 scenario for the year 2050, to shift their range fully or partially above the maximum altitude of the mountain. Of these, 65.1% are epiphytes. We found that species with narrow altitudinal ranges at high altitudes were more at risk. Our study indicated that conservation efforts should prioritise higher altitudinal sites, focusing particularly on preserving the vulnerable epiphytic fern species, which are likely to be at greater risk.

A new species of long-tailed shrew of the genus Sorex (Eulipotyphla: Soricidae) from Sierra de Omoa, Honduras

The only known species of the genus Sorex in Honduras is Sorex mccarthyi Matson & Ordóñez-Garza, which is endemic to Celaque National Park. This species shows the presence of a postmandibular foramen and canal, a characteristic that is useful to distinguish between species south of the Isthmus of Tehuantepec and unique to the Sorex salvini species group. Recently, two specimens of Sorex were collected in 2018 at Cusuco National Park, northwestern Honduras. These specimens lack the distinctive characteristics possessed by the S. salvini species group and belong to the Sorex veraepacis species group. Previously, the S. veraepacis species group was only known from the highlands of the southern Mexican state of Chiapas and Guatemala. Principal component analysis shows that specimens from Sierra de Omoa are different in size and shape with respect to other known species (i.e., S. veraepacis Alston, S. ibarrai Matson & McCarthy and S. madrensis Matson & Ordóñez-Garza). We describe these two specimens, currently known only from an isolated cloud forest in the Sierra de Omoa, Honduras, as a new species.

First Report of Arceuthobium hondurense in Oaxaca, Mexico

Honduran dwarf mistletoe (Arceuthobium hondurense Hawksw. & Wiens) has only been found in four locations in Honduras: west of Zamorano, east of Lepaterique, Cusuco National Park, and Celaque National Park (1,2). At one time it was believed that this mistletoe could be in danger of extinction (1). However, it has also been reported in two locations in Chiapas, Mexico (3). In December 2000, ≈1 km north of Suchixtepec, Oaxaca, Mexico, near Route 175 (elevation 2,770 m), we collected a dwarf mistletoe parasitizing Pinus tecunumanii (Schw.) Eguiluz et Perry that was morphologically similar to A. hondurense (1). This population initially had been classified as A. nigrum Hawksw. & Wiens (1), but is now classified as A. hondurense based on morphology (male flower color and stigma length) (1) and analysis of nuclear rDNA internal transcribed spacer (ITS) sequences from Honduras (GenBank Accession No. AF325969) and Oaxaca (GenBank Accession No. AY055215). A comparison of these two A. hondurense ITS sequences indicated they are very closely related to each other, whereas both are distinct from A. nigrum (GenBank Accession No. L25693). Specimens of A. hondurense from Oaxaca were deposited at the Deaver Herbarium, Northern Arizona University, Flagstaff. To our knowledge, this is the first report of A. hondurense in Oaxaca, Mexico, and extends its known distribution west across the Isthmus of Tehuantepec from central Chiapas by ≈400 km. References: (1) F. G. Hawksworth and D. Wiens. Dwarf Mistletoes: Biology, Pathology, and Systematics. USDA Agric. Handb. 709, 1996. (2) R. Mathiasen et al. Phytologia 85:268, 1998. (3) R. Mathiasen et al. Plant Dis. 85:444, 2001.

First Report of Arceuthobium hondurense on Pinus tecunumannii

Honduran dwarf mistletoe (Arceuthobium hondurense Hawksw. & Wiens) is a rare dwarf mistletoe found only in Honduras (1,2). Thus far, it has been reported to parasitize only Pinus oocarpa Schiede (2). In October 1999, we observed infection by A. hondurense on P. tecunumannii (Schw.) Eguiluz et Perry along the trail to the summit of Montana del Celaque (elevation 1,750 to 1,800 m) on the east side of Celaque National Park, ≈5 km west of Gracias (Department Lempira), Honduras. Infected pines had witches′ brooms, and mistletoe shoot production was common on infected branches. This is the first report of A. hondurense on P. tecunumannii. Specimens of A. hondurense from P. tecunumannii were collected and have been deposited at the Herbario, Escuela Nacional de Ciencias Forestales, Siguatepeque, Honduras, and at the Deaver Herbarium, Northern Arizona University, Flagstaff. References: (1) F. G. Hawksworth and D. Wiens. 1996. Dwarf Mistletoes: Biology, Pathology, and Systematics. U.S. Dep. Agric. Agric. Handb. 709. (2) R. Mathiasen et al. Phytologia 36:211, 1998.

First Report of Psittacanthus angustifolius on Pinus oocarpa and Pinus maximinoi

The mistletoe Psittacanthus angustifolius Kuijt (Loranthaceae) was first described in 1987 on Pinus from Nicaragua near the Honduran border, but the species of pine was not designated (1). Kuijt (1) speculated that this mistletoe probably also occurs in Honduras. During March and October 1999 we observed P. angustifolius parasitizing Pinus oocarpa Schiede in the departments of Choluteca, Francisco Morazan, El Paraiso, Intibuca, Lempira, and Olancho in Honduras. This mistletoe appears to be a very common parasitic plant on pines in Honduras and is associated with host mortality. We also observed P. angustifolius parasitizing Pinus maximinoi H.E. Moore at two locations in the department of Lempira: one infection on a single tree 1.5 km east of El Matazano (elevation 1,400 m) and six and eight infections on two trees 0.5 km west of the main entrance to Celaque National Park east of Gracias (elevation 1,200 m). This is the first report of P. angustifolius in Honduras and the first report of this mistletoe on Pinus oocarpa and Pinus maximinoi. Specimens of P. angustifolius from Pinus oocarpa and Pinus maximinoi have been deposited at the Herbario, Escuela Nacional de Ciencias Forestales, Siguatepeque, Honduras, and at the Deaver Herbarium, Northern Arizona University, Flagstaff. Reference: (1) J. Kuijt. Ann. Mo. Bot. Gard. 74:511, 1987.