life strategies of mosses in mt pulag benguet province

Philippine Journal of Science136 (1): 11-18, June 2007ISSN 0031 - 7683

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Roland M. Hipol*, Danielo B. Tolentino2, Edwino S. Fernando3, and Nia M. Cadiz2

Key Words: mosses, Bryophyta, Mt. Pulag, life strategies, altitudinal zonation

*Corresponding author: [email protected]

Life Strategies of Mosses in Mt. Pulag,Benguet Province, Philippines

1Department of Biology, College of ScienceUniversity of the Philippines Baguio, Baguio City, Philippines

2Plant Biology Department, Institute of Biological SciencesUniversity of the Philippines Los Baos, Los Baos, Laguna, Philippines

3Makiling Center for Mountain EcosystemsUniversity of the Philippines Los Baos, Los Baos, Laguna, Philippines

Plant Biology Department, Institute of Biological Sciences

Mt. Pulag, the highest peak in Benguet Province, Luzon Island, Philippines at 2,924 m (Buot and Okitsu 1998) was investigated for its moss flora focusing on life strategies. Moss collections totaled 58 species that belong to 28 families. These are distributed among 3 vegetation zones; the pine forest, mossy forest, and the mountain top grassland. Five out of the 6 main life strategies of During (1979 and 1992) were observed to occur; namely colonists, fugitives, annual shuttle species, long lived shuttle species, and perennials. The frequency of colonists, many of them belonging to the genus Campylopus, was moderately high ranging between 40% and 50% at the grassland and at the pine forest while it was lower in the mossy forest at 29%. Fugitives and annual shuttle species were observed to occur only in the pine forest. Perennials were highest in the mossy forest (45%), most of them belong to the family Hypnaceae. The long lived shuttle and colonist strategies dominated the grassland. This survey on life strategies resulted in the establishment of a moss based zonation pattern in Mt. Pulag as follows: colonist-annual shuttle strategies at ~2,850 m (grassland), perennials at ~2,725 m (upper boundary of the mossy forest), mixed perennials and colonists at 2,590 m (lower boundary of the mossy forest) and mixed life strategy zone with the more desiccation tolerant strategies with the highest frequencies at ~2,440 m (pine forest). This zonation pattern coincides with the vegetation pattern suggested by Merill and Meritt (1910).

INTRODUCTIONMosses are remarkably successful plants that thrive alongside more conspicuous vascular plants. They originated during the Upper Ordovician-Lower Silurian border (~440 million years) together with the first land plants (Shaw and Goffinet 2000). They are currently represented by approximately 10,000 species worldwide.

They colonize diverse habitats from high mountains to deep forests (Shaw and Goffinet 2000); and even in hot deserts though sporadic (Flowers 1973). They make up the largest and most familiar group of bryophytes.

The Philippines, being a tropical country, is conducive to rich growth of bryophytes. However, very few scientists and researchers have taken interest in this very rich bryological vegetation (del Rosario 1979). An aspect of Philippine bryology where there is even more of a lack of

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Hipol et al.: Life Strategies of Mosses in Mt. Pulag, Philippines

Philippine Journal of ScienceVol. 136 No. 1, June 2007

information, is the relationship of these organisms with the unique set of environmental conditions prevailing in the different ecological zones of the country. Mosses are the perfect indicator species of the stature of the environment because the possibility that they are artificially introduced in an ecosystem is practically nil. As such, their existence and current state truly reflect what the ambient environment really is.

Distinct environmental zones with increasing altitude on Mt. Pulag, Benguet are reflected by the occurrence of different vegetation zones on its slopes recently elaborated by Buot and Okitsu in 1998. The first zone they described was the pine forest (Pinus kesiya). Merill and Meritt (1910) describe this vegetation as occupying the main bulk of the mountain slopes up to an elevation of 2,600 m. Jacobs (1972) explains that this vegetation type is both a regeneration type of vegetation preparing the ground for the primary forest (mossy forest), and a destruction stage vegetation because of the recurring fire that prevents the mossy forest to be next in the succession. The upper limit of the pine forest is the mixed pine and broad-leafed forest at the boundary of the pine and mossy forest (Pinus-Deutzia-Schefflera).Above this vegetation type is the mossy forest (Lithocarpus-Dacrycarpus-Syzygium-Leptospermum). Merill and Meritt (1910) vividly describe this forest being made up of dense stand of small, irregularly shaped trees, comprising numerous species, the ground, and trunks and branches of trees being covered with a profusion of mosses, scale mosses, lichens, epiphytic ferns and orchids. The highest vegetation type is the grassland (e.g. Yushania, Calamagrostis, Deschampsia) at the peak of the mountain. Merill and Meritt (1910) mention that this is the only mountain in the Philippines that has a well defined grass vegetation above the mossy forest.

Bryophyte (mosses in particular) responses among these zoneswould be expected to differ as these organisms are generally considered to be strongly sensitive to microclimatic (Frahm 2002). Currently, there is much interest within ecology in integrated sets of plant traits that accompany particular sets of ecological conditions (During 1979,1992). Grime (1979) named these combinations of characters strategies. Stearns (1976)

defined these as sets of co-adapted traits designed, by natural selection, to solve particular ecological problems. Bryophyte life strategy categories have been refined in successive papers by During (1979, 1992). He proposed several categories of bryophyte life strategies and correlated these to environmental conditions where such a tactic is observed. This classification was based on 3 major trade-offs: (1) few large spores to many small spores, (2) survival of the difficult season as spores only, discarding the gametophyte (avoidance) versus survival of the gametophyte (tolerance), and (3) for the tolerance group, potential life span of the gametophyte, which is negatively correlated with reproductive effort. This resulted to the establishment of different life strategy tactics namely: fugitives, colonists, perennials, annual shuttles, short lived shuttles and long lived shuttles. In 1992, during modifies these categories emphasizing the heterogeneity within the colonists and perennial life strategies. As such, he created sub-categories under the Colonist strategy namely: ephemeral colonists, colonists sensuo stricto and pioneers. Under the perennial life strategy, he distinguished competitive perennials from stress tolerant perennials. Table 1 and 2 summarizes the characteristics of the different life strategies.

These aspects of moss research, especially in our country have not been dealt with satisfactorily in the past. Expressions of this response in the form of diverse life strategies are facets of moss biology that is the interest of this paper.

MATERIALS AND METHODSFour collection sites were identified in the different vegetation zones:

pine forest at ~2440 m

mossy forest (lower altitude) at ~2590 m

mossy forest (higher altitude) at ~2725 m

grassland at ~2850 m.

Field work was carried out in the first weeks of May and September 2003, in the first weeks of February and in April 2004. Sampling was done within the different vegetation zones recognized by Merill and Merritt (1910)

Table 1: Life strategy categories according to During (1979)

Potential Life span (yr) Life strategy

Reproductive Effort

Spores numerous, very light (20 m)

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through the multiple or multi-stage stratified sampling method. In this method, the population is subdivided or partitioned into strata, and each stratum is sampled separately. Partitioning is typically done so as to make each stratum more homogeneous than the overall population. For this research, the primary strata were the different collection sites as determined by altitude and the identified vegetation types of Merill and Meritt (1910). Collection at the pine forest was at ~2440m; at the blower edge of the mossy forest at ~2725m; at the upper boundary of the mossy forest at ~2590m; and at the grassland at ~2850m. The second strata were the different substrate preferences (tree, rock, soil) in each of the identified elevation. Mosses in these substrates were scored (species occurrence and cover) using a 625 cm2 quadrat (0.25 x 0.25 m). The presence or absence of each species in each habitat type and in each vegetation zone was noted. Identification was done using Bartrams (1939) Mosses of the Philippines and Eddys (1996) Handbook on Malesian Mosses. Validation of the scientific names and identification of difficult taxa were done in the Cryptogamic Laboratory of the National University of Singapore under the supervision of Dr. Benito Tan. Voucher specimens of the collected mosses are also deposited at this facility.

The classification of bryophyte life strategies followed that proposed by During (1979).

Site DescriptionMt. Pulag (163036 N; 1205020E) is the highest peak in Luzon island at 2,924m (Buot and Okitsu 1998). Together with Mt. Tabayoc and Mt. Panotoan, it forms the Mt. Pulag National Park. The park covers an area of about 11,560 ha lying on the north to south spine of the Gran Cordillera Central. The municipalities of Bokod, Kabayan, and Buguias of the province of Benguet, Tinoc of Ifugao, and Kayapa of Nueva Vizcaya bound it.

Buot and Okitsu (1998) determined that the annual mean temperature at 2000m is 16C. At the upper limit of the pine forest (2300m), the temperature is 14C. At elevations around 2800m the annual mean temperature is around 12C. The mountain is also characterized by having a vegetation zonation pattern unique from other mountains in that it does not have a dipterocarp flora in its lower slopes. In the publication of Merrill and Merritt (1910), they recorded a total of 57 bryophyte species, 91 fern species, 3 gymnosperms and 377 angiosperms for Mt. Pulag.

RESULTSThe moss collections from Mt. Pulag totaled 58 species that belong to 28 families bringing overall inventory to 144 species, an increase of 27 species from the previous count of 117 (from those documented by Bartram in 1939 and Tan and Iwatsuki in 1991). Table 3 summarizes the collected specimens.

Life Strategy and Vegetation TypeFive out of the six life strategies of During (1979) have been observed to occur in the moss populations of Mt. Pulag. The only strategy that was not seen was the short lived shuttle. As can be observed, the frequency of colonists in all of the collection sites is quite high, however lesser in mossy forest 1 (~2725 m). Fugitives and annual shuttle species are observed to occur only in the pine forest. The frequency of perennials and long lived shuttle species vary between the different collection sites. For perennials, the mossy forests are the habitats that they prefer basing on the relatively high frequency of occurrence of this strategy in the two collection sites. The long lived shuttle dominate the grassland. Abundance of the different life strategies are shown in Figure 1 and 2.

Table 2: Life strategy categories according to During (1992)

Potential Life span (yr) Life strategy Reproductive Effort

Spores numerous, very light (20 m)

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Figure 2. Abundance of life strategies from the different vegetation zones/elevation in %s.

see next page for continuation . . . .

Table 3. Moss species collected from Mt. Pulag, Benguet Province Philippines together with their family, vegetation type of location, expressed life strategy, and substrate (During 1979)

Species Family Vegetation Type** Life strategy

Anoectangium aestivum Pottiaceae pine Colonist

Anomobryum gemmigerum Bryaceae pine Colonist

Anomobryum gemmigerum Bryaceae pine Colonist

Barbella flagellifera Meteoriaceae m1 Perennial

Bryum clavatum Bryaceae pine Unknown

Figure 1. Abundance of each moss life strategy in each of the vegetation zones in %s.

0%20%40%60%80%

100%

colon

ist

annu

al

fugitive

short live

d

long lived

perenn

ial

unknow

n

Life Strategy

% o

ccu

rren

ce Pine Forest (~2440 masl)

Mossy Forest 2 (~2590 masl)Mossy Forest 1 (~2725 masl)Grassland (~2850 masl)

0%10%20%30%40%50%60%70%80%90%

100%

Gras

sland

(~28

50 m

asl)

Moss

y Fore

st 1 (

~272

5ma

sl)

Moss

y Fore

st 2 (

~259

0ma

sl)

Pine F

orest

(~244

0 mas

l)

Vegetation Type/Elevation

% oc

curre

nce

unknownperenniallong livedshort livedfugitiveannualcolonist

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see next page for continuation . . . .

Bryum ramosum Bryaceae pine Colonist

Calyptrochaeta remotifolia Hookeriaceae m1 Long lived shuttle

Calyptrochaeta remotifolia Hookeriaceae grassland Long lived shuttle

Campylopus austrosubulatus Dicranaceae grassland Colonist

Campylopus austrosubulatus Dicranaceae m2 Colonist

Campylopus hemitrichius Dicranaceae grassland Colonist

Campylopus hemitrichius Dicranaceae m1 Colonist

Campylopus hemitrichius Dicranaceae grassland Colonist

Campylopus hemitrichius Dicranaceae pine Colonist

Campylopus laxitextus Dicranaceae pine Colonist

Campylopus laxitextus Dicranaceae grassland Colonist

Campylopus sp. Dicranaceae pine Colonist

Campylopus umbellatus Dicranaceae m2 Colonist

Campylopus umbellatus Dicranaceae m2 Colonist

Campylopus umbellatus Dicranaceae pine Colonist

Clastobryum caudatum Sematophyllaceae pine Long lived shuttle

Ctenidium andoi Hypnaceae m2 Perennial



Ctenidium lychnites Hypnaceae m1 Perennial

Dicranodontium fleischerianum Dicranaceae m2 Colonist

Dicranodontium fleischerianum Dicranaceae m1 Colonist

Dicranoloma brevisetum Dicranaceae m1 Colonist



Dicranoloma reflexum Dicranaceae m2 Colonist

Dicranoloma sp (billarderi) Dicranaceae m1 Colonist

Dicranum psathyrum Dicranaceae pine Colonist

Ditrichum dificile Ditrichaceae pine Colonist

Ectropothecium falciforme Hypnaceae m2 Long lived shuttle

Entodon sp. Entodontaceae pine Perennial

Entosthodon buseanus Funariaceae pine Annual

Eurhynchium asperisetum Brachytheciaceae m2 Perennial

Eurhynchium asperisetum Brachytheciaceae m2 Perennial

Fissidens nobilis Fissidentaceae m1 Colonist

Fissidens nobilis Fissidentaceae m2 Colonist

Fissidens plagiochiloides Fissidentaceae m2 unknown

Funaria hygrometrica Funariaceae pine Fugitive

Gammiella ceylonensis Sematophyllaceae grassland unknown

Gammiella ceylonensis Sematophyllaceae pine unknown

Gollania benguetense Hypnaceae pine unknown



Homaliodendron flabellatum Neckeraceae m2 Perennial

Hookeria acutifolia Hookeriaceae m1 Long lived shuttle

Isothecium trichocladon Lembophyllaceae m2 Perennial

Leiomela javanica Bartramiaceae m1 Long lived shuttle

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DISCUSSIONOverall affinities of specific life strategies to the different altitudinal vegetation zones have been found. The following discuss the observed moss based vegetation pattern correlated with the dominant vegetation pattern mentioned by Merill and Meritt (1910).

Grassland Moss FloraThe absence of a tree canopy that could protect against intense light and high wind velocity makes the grassland environment particularly desiccating for such organisms, and may be the prime reason why the grassland is the

most inhospitable of the zones for mosses. Colonist (Campylopus spp) and long lived shuttle strategies (Calyptrochaeta remotifolia), being the life strategies fit for this kind of environment, are dominant. Annual shuttle strategy described by During (1979) is strongly determined by seasonal fluctuations and a severe stress period which is avoided by being in the spore stage only. During (1979) also describes the colonists as a strategy that is adapted to environments that are unpredictable, but are more or less predictably last for some years. Colonists also often appear early in the succession series. However, the idea that the presence of colonists in the grasslands may signify succession may not be correct. Because of

Leucobryum aduncum var. scalare Leucobryaceae pine Perennial

Macromitrium reinwardtii Orthotrichaceae pine Long lived shuttle

Macromitrium reinwardtii Orthotrichaceae grassland Long lived shuttle

Macromitrium reinwardtii Orthotrichaceae m2 Long lived shuttle

Macromitrium sulcatum Orthotrichaceae pine Long lived shuttle

Meteoriopsis reclinata Meteoriaceae pine Long lived shuttle

Miothecium microcarpum Sematophyllaceae pine Long lived shuttle

Mnium laevinerve Mniaceae m1 unknown

Mnium laevinerve Mniaceae m1 unknown

Papillaria fuscescens Meteoriaceae m2 Long lived shuttle

Plagiomnium integrum Mniaceae m1 unknown

Plagiothecium neckeroideum Plagiotheciaceae m1 Perennial

Plagiothecium nemorale Plagiotheciaceae m1 Perennial

Platyhypnidium muelleri Meteoriaceae m1 Perennial

Pogonatum perichatiale Polytrichaceae pine Colonist

Pogonatum proliferum Polytrichaceae m2 Colonist

Pogonatum proliferum Polytrichaceae m1 Colonist

Pogonatum urnigerum Polytrichaceae m2 Colonist

Pogonatum urnigerum Polytrichaceae m1 Colonist

Pohlia elongata Bryaceae pine Colonist

Racomitrium subsecundum Grimmiaceae pine Unknown

Racopilum johannis-winkleri Racopilaceae m1 Unknown

Racopilum johannis-winkleri Racopilaceae m1 Unknown

Rhodobryum giganteum Bryaceae m1 Colonist

Sphagnum cuspidatulum Sphagnaceae m1 Long lived shuttle

Syrrhopodon tjibodensis Calymperaceae pine Colonist

Taxiphyllum taxirameum var. recurvifolium

Hypnaceae m1 Perennial

Thamnobryum subserratum Thamnobryaceae m1 Perennial

Thuidium cymbifolium Thuidiaceae m1 Perennial

Trachyloma indicum Pterobryaceae m1 Perennial

Trachyloma indicum Pterobryaceae m1 Perennial

Trachypodopsis serrulata Trachypodaceae m1 Perennial

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the prevalent drying conditions, this situation may be considered as auto-succession (Longton 1992). Longton adopts the definition of auto-succession as a succession that consists of a single stage, in which pioneer and climax species are the same. It occurs particularly where climatic severity so restricts the number of species that competition is minimized and displacement fails to occur. In this particular situation, the colonists, by themselves are also the climax species of the grassland.

Mossy Forest Moss FloraThis vegetation type is the richest habitat for bryophytes. The abundance of long span life strategies (long lived shuttles and perennials) demonstrate that the environment is stable and humid enough for long periods of moss growth. During (1979) also adds that these strategies exist in environments where even if there are fluctuations in the environment, these changes are within the tolerance range of these organisms. Gradstein and Pocs (1989) explain this abundance as a result of more favorable moisture conditions due to clouds and fog and the prevailing lower temperatures. Gonzales-Mancebo and Hernandez-Garcia (1996) also found this out in their research on the life strategies of mosses in the Canary Islands. Ecophysiologically, temperature and insulation may have been optimal in this environment that assimilation exceeds that of respiration as evidenced by the high bryophyte biomass estimated at 1053.9 kg/ha (Frahm 1990). The dominance of perennial life strategies facilitates the conclusion that the bryophyte flora in the mossy forests is the climax community.

Pine Forest Moss FloraBryophyte flora in this vegetation zone is unique in that it is only here that the short life span strategies are found (annual shuttle species and fugitives) together with colonists. Perennial strategists were conspicuously scarce. The presence of short lived strategy types suggests that there are strong seasonal fluctuations and severe stress periods that are purposely avoided by the bryophytes being present in the spore stage only. The colonists in this zone may be in the category described by During (1992) as sensuo stricto because they colonize available productive habitats that resulted from disturbance. The seasonal fires within the pine forest explain the predominance of these types of strategies. The low density of pine trees, which results to an opened canopy is dictated by the pines ecophysiological character of being light demanding and germinating only on bare soil (Jacobs 1972). This condition makes this habitat less humid and dry for perennial strategists.

CONCLUSIONMt. Pulag bryoflora is one of the more diverse communities of bryophytes especially of mosses. It is here that many of the mosses and other organisms find their last refuge in view of the continuous and large-scale land conversion happening throughout the country. It is also where life strategy distribution has never been investigated. In this view, this research is pioneering. The study on these facets of moss biology has resulted in the establishment of moss based zonation pattern in Mt. Pulag conforming to the boundaries of Merill and Merrits (1910) 3 distinct vegetation zones. The following moss-life-strategy based zonation would be: (1) Mixed strategy Zone where those with short life spans are present (Fugitives and Annual Shuttle species) at the pine forest, (2) Perennial Stayers and Long Lived Shuttle Zone within the mossy forest, and (3) Colonists-Annual Shuttle Species Zone at the grassland. The dominance of these life strategies unique to each of the vegetation zones illustrates the distinctly different environmental conditions offered by each of these ecosystems to which the mosses have to adapt to. It would be very interesting to determine what these factors are that specifically favor the abundance of specific strategies. In the words of During (1992), results of these types of researches are a valuable guide in the further investigation regarding environmental key factors that define specific environments or regions.

ACKNOWLEDGEMENTSWe would like to thank Dr. Benito Tan of the National University of Singapore for his invaluable help in the identification of the moss collections, and Dr. Inocencio Buot and Prof. Maria Fe Sangalang of UP Los Baos for the help in the preparation of this research. Our gratitude also to the Tan Kin Chee Foundation for a small grants award, SEARCA-SEAMEO for the thesis grant, and UP Baguio for the Local Faculty Fellowship grant to the corresponding author. The assistance of Mr. Orlando Apostol, Ronnel Almazan, and Rexel Almazan during field work is also gratefully acknowledged.

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life strategies of mosses in mt pulag benguet province

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