Moss Distribution in the Yucatán Peninsula

Chapter 18 Moss Distribution in the Yucatán Peninsula Claudio Delgadillo M. INTRODUCTION Mosses are represented by a small number of species in the Yucatán Peninsula. According to Millspaugh (1895, 1896, 1898), Standley (1930), and Steere (1935), there were 39 species in the area. However, studies by Delgadillo and co-workers (Delgadillo, Cárdenas, and Sharp 1982; Delgadillo and Cárdenas 1982; Delgadillo 1984) identified a total of 69 moss species and varieties. The number of species remained essentially unchanged in The Moss Flora of Mexico (Sharp, Crum, and Eckel 1994), but recent field work has served to add precision to the floristic data. Despite the number of moss species, the peninsular moss flora is of interest because it maintains important floristic connections with mainland Mexico, Central America, and the West Indies. From the phytogeographic point of view, study of the peninsular moss flora may identify routes of migration in the Caribbean basin while, from a strict biological perspective, it illustrates the morphological diversity and adaptive strategies that merit further investigation. Delgadillo (1984) described the main patterns of distribution and made reference to the occurrence of phenotypic convergent features among the peninsular mosses. This paper offers additional comments on the distribution of the peninsular moss flora. Thanks are extended to Dr. Kenneth D. McFarland, University of Tennessee, for assistance with herbarium records. Dr. Ronald A. Pursell, Pennsylvania State University, identified all Fissidens specimens. Angeles Cárdenas assisted in the identification of specimens and in field and herbarium work. Field work in eastern Quintana Roo in October 2000 was made possible by Dr. Arturo Gómez- Pompa, Reserva Ecológica El Edén and by Project "A Biodiversity Survey of Poorly- Known Taxa from Quintana Roo, Mexico" supported by UC Mexus. Field assistance by El Edén personnel is greatly appreciated. 327

328 THE LOWLAND MAYA AREA METHOD A list of moss species in the Yucatán Peninsula was compiled from herbarium and bibliographic sources. Field work conducted at the El Edén Ecological Reserve in the state of Quintana Roo (21 12' N to 87 11' W) in October 2000 yielded additional data on local moss distribution. A complete set of specimens was deposited at MEXU, the Bryophyte Collection at the National University of Mexico, where herbarium materials collected in 1980 1981 were also available. The nomenclature was updated according to recent treatments (see Delgadillo, Bello, and Cárdenas 1995), and the latitudinal distribution (expressed as geographical coordinates) was obtained for further analysis. Following a previous study (Delgadillo 1984), the Yucatán Peninsula was divided into four latitudinal areas: (1) 17 48' to 19 S (southern); (2) 19 01' to 20 (S-C or south-central); (3) 20 01' to 21 (N-C or north-central); and (4) 21 01' to 21 33' (N or northern). The presence or absence of all known species was recorded in an OGU (Operational Geographical Units) data matrix that served first as the basis for the computation of Jaccard s index of similarity, and then to obtain the UPGMA (unweighted pair-group method, arithmetic average) dendrograms that show the relationships among OGUs (states and latitudinal subdivisions) in the peninsula. An NTSYS-PC software package, version 2.0 (Exeter Software, New York), facilitated the analyses. RESULTS The moss flora of the Yucatán Peninsula contains 70 species and varieties (table 1). Three additional species have been mentioned elsewhere for the area. Sharp, Crum, and Eckel (1994) recorded Bryum procerum Schimp. from the state of Yucatán, but this is based on a mistaken citation by Ochi (1981) that refers to a Venezuelan locality. Squamidium nigricans (Hook.) Broth., cited from Quintana Roo (Sharp, Crum, and Eckel 1994) with no reference to any specimen, remains unconfirmed. The presence of Didymodon rigidulus Hedw., originally cited as D. acutus (Brid.) Saito, is still questionable as examination of the supporting specimen has not been possible. Among the mosses of the Yucatán Peninsula, 20 species are locally frequent and broadly distributed, as shown by their presence in the four latitudinal subdivisions. Such species as Calymperes afzelii, Entodontopsis leucostega, Henicodium geniculatum, Leucobryum incurvifolium, Octoblepharum albidum, and others in Table 18.1, illustrate this pattern among the epiphytes while Barbula agraria, Barbula indica, Hyophila involuta, and

Moss Distribution in the Yucatán Peninsula 329 TABLE 18.1. Moss species and their state and latitudinal distribution in the Yucatan Peninsula C Y QR Species 1 2 3 4 x x x Acroporium longirostre x x x - - x - Anoectangium aestivum - - x - x x x Barbula agraria x x x x x - x Barbula indica x x x x x - x Brachymenium globosum - x - x x - - Brachymenium klotzschii x - - - - x - Bryoerythrophyllum recurvirostrum var. aeneum - - x - x x x Bryum apiculatum x - x x x x x Bryum coronatum x x x - x - x Calymperes afzelii x x x x - - x Calymperes erosum - - - x - - x Calymperes lonchophyllum - x - x x x x Calymperes palisotii x x x x - - x Calymperes tenerum - - x - x - x Chryso-hypnum diminutivum x x x x - x x Cryphaea filiformis - x x x - x - Cryphaea patens - - x x x x x Cyrto-hypnum involvens x - x - x x x Cyrto-hypnum schistocalyx x - x - - x - Didymodon rigidulus var. gracilis - - - x x x x Entodontopsis leucostega x x x x x - - Entodontopsis nitens x - - - x x x Erpodium domingense x - x x - x - Eulacophyllum cultelliforme - - - x x x x Fissidens pallidinervis x - x - x x x Fissidens radicans x x x - x x x Fissidens santa-clarensis x x x x x - - Fissidens serratus x - - - - x - Fissidens steerei - - x - x x x Fissidens yucatanensis - - x -

330 THE LOWLAND MAYA AREA TABLE 18.1 (Continued) C Y QR Species 1 2 3 4 x x x Fissidens zollingeri x - x - x x - Funaria hygrometrica var. Calvescens - - x - x x x Groutiella tumidula x x x x x - x Henicodium geniculatum x x x x - x - Hyophila bartramiana - - x - x x - Hyophila involuta x x x x - - x Isopterygium tenerum x - x - x - - Jaegerina scariosa x - - - x x x Leucobryum incurvifolium x x x x x x - Luisierella barbula - - x - x - x Neckeropsis undulata x - - - x x x Neohyophila sprengelii x x x x - x - Neohyophila sprengelii var. stomatodonta - x - - x x x Octoblepharum albidum x x x x - - x Orthostichopsis tetragona x x - x x x x Papillaria nigrescens x - x x - x x Philonotis uncinata var. uncinata- x x - - - x Pilosium chlorophyllum - x - - x x x Pireella cymbifolia x x x x x x - Pireella pycnothallodes x - x - x x x Pseudocryphaea domingensis x x x x x x x Racopilum tomentosum x x x - x - x Schlotheimia rugifolia x - - x x x - Schoenobryum concavifolium x - x - x x x Sematophyllum adnatum x x x x - - x Sematophyllum cuspidiferum - x - x - x - Sematophyllum galipense - - - x x x x Sematophyllum subpinnatum x - - x x x x Splachnobryum obtusum x - x - x x x Stereophyllum radiculosum x x x x x x x Syrrhopodon incompletus var. incompletes x x x x x x x Syrrhopodon parasiticus x x x x

Moss Distribution in the Yucatán Peninsula 331 C Y QR Species 1 2 3 4 x x x Taxithelium planum x x x x - - x Taxithelium portoricense - x x - - - x Trichosteleum sentosum x x x - x x x Trichostomum crispulum x - x - x x - Trichostomum portoricense x - x - - x - Vesicularia vesicularis var. rutilans - - x - x x x Weissia jamaicensis x - x - - - x Zelometeorium patulum x - - - 48 49 50 TOTAL 48 34 52 35 C = Campeche; Y = Yucatán; QR = Quintana Roo; 1 = 17 48' -19 S; 2 = 19 01' 20 S-C; 3 = 20 01' 21 N-C; 4 = 21 01' 21 33' N. Neohyophila sprengelii are apparently obligate calcicolous species whose distribution is linked to limestone formations (Breen 1963; Serrano 1996). The moss flora in all peninsular states is similar in size, with nearly half (31 species) of their mosses common to all of them (table 1). The remaining 39 species are either known from state pairs or are restricted to single states in the Yucatán Peninsula (Table 18.2). As the number of shared species among the states is large, the overall similarity values are close to one another (0.56 0.63), but cluster analysis indicates that Campeche (C) and Quintana Roo (QR) are closer to each other than to the state of Yucatán (Figure 18.1). The distribution of mosses along a latitudinal gradient shows the absence of a peninsular effect that is, there is no progressive reduction of the number of species from the base to the tip of the peninsula (Figure 18.2). Cluster analysis indicates closer similarity between the northern and south-central sections, and between the southern and north-central sections (Figure 18.3). These similarities, however, may be an artifact induced by a better exploration record in those sections. DISCUSSION Compared to other tropical areas, the peninsular moss flora includes a small number of species. For an area nearly 140,000 km 2, the number of species is considerably smaller than that of neighboring Chiapas, which has an area of 74,211 km 2 and a moss flora of about 327 species. The Valley of

332 THE LOWLAND MAYA AREA TABLE 18.2. Number of species shared among states and size of the peninsular moss flora States Campeche Quintana Roo Yucatán TOTAL Campeche 4 --- --- 48 Yucatán 6 2 10 49 Quintana Roo 7 10 --- 50 Species shared by all states 31 Species restricted to one or two states 39 Total number of species in moss flora 70 Mexico, with an area of about 7,500 km 2 has some three hundred moss species (Cárdenas 1999); Cuba, with a land area of 115,000 km 2, has a moss flora containing more than 370 species. Several factors explain, at least in part, the reduced size of the peninsular moss flora. Most of the Yucatán Peninsula is a lowland limestone area characterized by an undulating topography and the near absence of surface waterways (Beltrán 1959; Miranda 1958b). Precipitation in the southernmost section (outside the area of study) may reach 5,000 millimeters (mm), and 1,000 to 1,100 mm elsewhere in the peninsula; in the northern part, it may reach only 500 mm (Miranda 1958b). With these values, rainfall may not be a limiting factor, but the rapid drainage through the limestone may produce a comparatively dry environment that would limit the number of moss habitats. C QR Y 0.56 0.58 0.60 0.61 0.63 FIGURE 18.1. Floristic relationship among the states of the Yucatán Peninsula, based on a cluster analysis of Jaccard s index of similarity values (C = Campeche; Y = Yucatán; QR = Quintana Roo).

Moss Distribution in the Yucatán Peninsula 333 FIGURE 18.2. Number of moss species per latitudinal subdivision in the Yucatan Peninsula. S N-C S-C N 0.45 0.50 0.55 0.59 0.64 FIGURE 18.3. Floristic relationship among the latitudinal subdivisions of the Yucatán Peninsula, based on a cluster analysis of Jaccard s index of similarity values. (S = southern [17 48' 19 ]; N-C = north central [20 01' 21 ]; S-C = south-central [19 01' 20 ]; N = northern [21 01' 21 33']).

334 THE LOWLAND MAYA AREA The area of study is mostly covered by subdeciduous forests (Miranda 1958a) that become smaller in stature northwards. Fire, hurricanes, and a long history of human occupation have altered the original vegetation and increased near-ground solar radiation and evaporation. The edge effect resulting from forest fragmentation and other natural causes, as well as anthropogenic disturbance, has led to the disappearance of habitats and the impoverishment of moss flora since historic times. [Such recurrent climatic changes such as the driest period in the last eight thousand years, dated between 1300 and 1100 yr. B.P. (~A.D. 800 1000 yr.; Hodell, Curtis, and Brenner 1995), must have especially affected mosses from the moister habitats in the Yucatán Peninsula. The effect of human activities deserves special notice as a force that reduces moss diversity. Agriculture and cattle raising have been major disturbances in the Yucatán Peninsula. According to García and Falcón (1984), from 3 to 24 percent of the surface area of each state is used for agriculture, and 14 to 17 percent is reserved for cattle raising. It is not clear whether these figures include areas where, through the traditional agricultural methods, land is abandoned after a period of cultivation. Along with wood extraction, the use of fire in land clearing practices, and such natural disturbances as Hurricane Gilbert in 1988, have caused extensive damage to vascular flora and have certainly depleted moss populations. Diversity was perhaps higher in the past. The geographical ranges exhibited by the peninsular mosses suggest that the Yucatán Peninsula has been the pathway of tropical floras (Delgadillo 1984) and that the interchange with neighboring areas is still in progress. With about ninety percent of the mosses shared with the West Indies, the near absence of endemics, and with no peninsular effect in evidence, this hypothesis seems acceptable. A larger number of endemics would signify strong selective pressures and insufficient time for dispersal of the products of speciation. The recognition of a peninsular effect, on the other hand, would show a progressive trend toward fewer species from the base toward the tip of the peninsula; the number of species observed in the four areas do not correspond to those resulting from a peninsular effect. However, the closer similarity between the moss floras of Campeche and Quintana Roo with respect to Yucatán (see Figure 18.1) indicates that the distribution of taxa is not entirely homogeneous throughout the peninsula and that the interchange between the continent and the islands has not been uniform. Whether at the state level or by latitudinal subdivision, there is a conspicuous group of moss species that are widespread in the Yucatán Peninsula (see Table 18.1). Their occurrence may be attributed to the ubiquitous limestone substrate, a widespread vascular flora, and to gradual climatic variation in the area. Ibarra-Manríquez, Villaseñor, and Durán (1995) indicate that about 50 percent of the arboreal species are shared among the

Moss Distribution in the Yucatán Peninsula 335 peninsular states, and Wendt (1993) described several distribution patterns of rain forest species that are common in the peninsula. Wendt (1993:616) noted that among rainforest species restricted to northern Mesoamerica in their continental distribution (excluding the Mexican endemics), the 43 species that occur in the Peninsula of Yucatan (Yucatan and widespread groups) have a much higher percentage also occurring in the Greater Antilles than the 61 nonpeninsular species. No evidence exists of a common history between the vascular species and the widespread epiphytic mosses cited in this contribution, but this range similarity calls for a closer look at the geographic distribution of mosses and their phorophytes in the Yucatán Peninsula. Knowledge of the peninsular moss flora is far from complete. Several areas may still yield new moss records for the area, and this will require the reevaluation of the proposed hypotheses. From the geographic point of view, the mosses from Belize and the Petén region of Guatemala are part of the Yucatán Peninsula and should be included to have a better view of the size and distribution of flora. Certain other features of the peninsular landscape are floristically important. The so-called Petenes and the Sian ka an National Park in eastern Quintana Roo have not been explored for mosses. The former represents a unique environment where mosses from the mainland may be associated with freshwater habitats in the sea. LITERATURE CITED Beltrán, E. 1959. Los recursos naturales del sureste y su aprovechamiento. I Parte. Capítulo IV, Ambiente. Ediciones del Instituto Mexicano de Recursos Naturales Renovables. D.F. Tomo 1, México. Breen, R. S. 1963. Mosses of Florida. An illustrated manual. Univ. Florida Press, Gainesville. Cárdenas S., A. 1999. Los musgos pleurocárpicos del Valle de México, México. Trop. Bryol. 16: 109 116. Delgadillo M., C. 1984. Mosses of the Yucatán Peninsula, Mexico. III. Phytogeography. Bryologist 87: 12 16. Delgadillo M., C., and A. Cárdenas S. 1982. Musgos de la Península de Yucatán, México. II. Bol. Soc. Bot. Méx. 43: 35 37. Delgadillo M., C., A. Cárdenas S., and A. J. Sharp. 1982. Mosses of the Yucatán Peninsula, Mexico. I. Bryologist 85: 253 257. Delgadillo M., C., B. Bello B., and A. Cárdenas S. 1995. LATMOSS, a catalogue of neotropical mosses. Monogr. Syst. Bot. Missouri Bot. Gard. 56: 1 191. García, E., and Z. Falcón. 1984. Nuevo Atlas Porrúa de la República Mexicana. Ed. Porrúa. 6 th ed. D.F., México. Hodell, D. A., J. H. Curtis, and M. Brenner. 1995. Possible role of climate in the collapse of Classic Maya civilization. Nature 375 (6530): 391 394.

336 THE LOWLAND MAYA AREA Ibarra-Manríquez, G., J. L. Villaseñor, and R. Durán G. 1995. Riqueza de especies y endemismo del componente arbóreo de la Península de Yucatán, México. Bol. Soc. Bot. México 57: 49 77. Millspaugh, C. F. 1895. Contributions to the flora of Yucatan. Field Columbian Mus. Bot. Ser. 1: 1 63. Millspaugh, C. F. 1896. Contribution II to the coastal and plain flora of Yucatan. Field Columbian Mus. Bot. Ser. 1: 277 339. Millspaugh, C. F. 1898. Contribution III to the coastal and plain flora of Yucatan. Field Columbian Mus. Bot. Ser. 1: 340 410. Miranda, F. 1958a. Rasgos fisiográficos (de interés para los estudios biológicos). In E. Beltrán, editor. Los recursos naturales del sureste y su aprovechamiento. II Parte. Capítulo IV, Ambiente. Ediciones del Instituto Mexicano de Recursos Naturales Renovables. D.F. Tomo 2, México. Miranda, F. 1958b. Estudios acerca de la vegetación. In E. Beltrán, editor. Los recursos naturales del sureste y su aprovechamiento. II Parte. Capítulo VI, Ambiente. Ediciones del Instituto Mexicano de Recursos Naturales Renovables. D.F. Tomo 2, México. Ochi, H. 1981. A revision of the neotropical Bryoideae, Musci (Second Part). J. Fac. Educ. Tottori Univ. Natur. Sci. 30: 21 55. Serrano, Y. 1996. The mosses of disturbed areas in the Municipality of Bayamón, Puerto Rico. Bryologist 99: 81 84. Sharp, A. J., H. A. Crum, and P. M. Eckel. 1994. The moss flora of Mexico. Mem. New York Bot. Gard. 69: i+xvii, 1 1113. Standley, P. C. 1930. Flora of Yucatán. Field Mus., Bot. Ser. 3: 157 492. Steere, W. C. 1935. The mosses of Yucatán. Amer. J. Bot. 22: 295 408. Wendt, T. 1993. Composition, floristic affinities, and origins of the canopy tree flora of the Mexican Atlantic slope rain forests. Pages 595 680 in T. P. Ramamoorthy, R. Bye, A. Lot, and J. Fa., editors. Biological diversity of Mexico: Origins and distribution. Oxford Univ. Press, New York.