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Transcript of When family matters: an analysis of Thelotremataceae (Lichenized Ascomycota: Ostropales) as...
ORI GIN AL PA PER
When family matters: an analysis of Thelotremataceae(Lichenized Ascomycota: Ostropales) as bioindicatorsof ecological continuity in tropical forests
Eimy Rivas Plata Æ Robert Lucking Æ H. Thorsten Lumbsch
Received: 10 April 2007 / Accepted: 24 October 2007 / Published online: 23 November 2007� Springer Science+Business Media B.V. 2007
Abstract We analysed patterns of habitat and microhabitat preferences of 19 families
(comprising 135 genera and 950 species) of crustose, corticolous lichens in Costa Rica
(Arthoniaceae, Arthopyreniaceae, Coenogoniaceae, Graphidaceae, Lecanoraceae, Letrou-
itiaceae, Monoblastiaceae, Pertusariaceae, Physciaceae, Pilocarpaceae, Porinaceae,
Pyrenulaceae, Ramalinaceae, Roccellaceae, Strigulaceae, Teloschistaceae, Thelenellaceae,
Thelotremataceae, Trypetheliaceae), in order to test whether Thelotremataceae are suitable
predictors of undisturbed tropical rain forest and can be used as bioindicators of ecological
continuity. The dataset consisted of 12,215 specimen samples and six environmental
parameters recorded for each sample (altitude, degree of seasonality, vegetation type,
disturbance level, substrate nature, light exposure), which were analysed by a multivariate
approach using principal component analysis (PCA). The analysis showed that three of the
19 families, Letrouitiaceae, Porinaceae, and Thelotremataceae, showed significant pref-
erences for undisturbed primary to old growth secondary forest, fully shaded to semi-
exposed microhabitats, and the bark of mature tree trunks, parameters assumed to be
correlated with ecological continuity of closed rain forest habitats. Thelotremataceae had
broader altitudinal range than Letrouitiaceae and Porinaceae and significantly higher genus
and species diversity (16 genera, 130 species) compared to Porinaceae (4 genera, 40
species) and Letrouitiaceae (1 genus, 5 species). Our results support the hypothesis that
Thelotremataceae perform best as predictors of undisturbed dry and lowland to montane
E. Rivas Plata � R. Lucking � H. T. LumbschDepartment of Botany, Field Museum of Natural History, 1400 South Lake Shore Drive,Chicago, IL 60605–2496, USA
R. Luckinge-mail: [email protected]
H. T. Lumbsche-mail: [email protected]
E. Rivas Plata (&)Ecology and Evolution Program, Biological Sciences Department, University of Illinois at Chicago,845 W Taylor Street, Chicago, IL 60607, USAe-mail: [email protected]
123
Biodivers Conserv (2008) 17:1319–1351DOI 10.1007/s10531-007-9289-9
rain forest and are the most suitable lichen bioindicators of ecological continuity in these
ecosystems. In contrast, Lecanoraceae, Pertusariaceae, Physciaceae, and Teloschistaceae,
were found to be predictors of disturbed and pioneer (micro-)habitats. We also found that,
among a variety of parameters tested, the Index of Ecological Continuity (IEC), adapted to
the use of Thelotremataceae in tropical forests, performs best in terms of predicting dis-
turbance levels and site history. A semi-taxonomic approach identifying morphotypes
rather than genera or species yielded the same results, making this method suitable for a
broader spectrum of potential users.
Keywords Crustose � Corticolous � Costa Rica � Lichen families
Tropical rain forests are the most diverse ecosystems on the planet, containing more than
half of all species (Terbourgh 1992; Phillips et al. 1994; Wilson 1999; Floren and Lin-
senmair 2005; Jablonski et al. 2006). They are not only valuable economic sources,
including ecotourism, food, pharmaceutical products, timber, protection of watersheds, and
carbon storage (Curran et al. 1999; Kremen et al. 2000; Pearce 2001; Dalton 2006), but are
living heritage and testimony to the evolution of life, in itself reason for their conservation
(Wilson 1984, 1999, 2002). Tropical rain forests continue to be deforested at alarming rates
(FAO 1981; Myers 1991; Skole and Tucker 1993; Achard et al. 2002; ITTO 2002), con-
tributing not only to regional and global climate change (Shukla et al. 1990; Still et al.
1999; Malhi and Grace 2000; Fearnside 2000, 2001; Lawton et al. 2001; Defries et al.
2002; Fearnside and Laurance 2004) but also the extinction of thousands of species (Lewin
1986; Raup 1986; Brook et al. 2006; Wright and Muller-Landau 2006). Tropical rain
forests are not only affected by clear-cutting, but also selective logging, slash-and-burn
agriculture, and fragmentation, being replaced by a mosaic of variously degraded forest
remnants, secondary vegetation, and partially recovering forest (Laurance et al. 2000;
Martin et al. 2004; Lamb et al. 2005).
Since the start of the conservation movement in the mid 20th century, increasing efforts
are being made to revert the effects of deforestation, by protecting remaining rain forest
and through reforestation and establishment of biological corridors (Uhl et al. 1988; Aide
et al. 2000; Margules and Pressey 2000; Barrow et al. 2002; Arroyo-Moya et al. 2005;
Lamb et al. 2005). However, conservation is expensive (Bonnie et al. 2000; Balmford and
Whitten 2003) and protective land use planning thus subject to economic decisions based
on financial resources, requiring selection among potentially available areas based on a
quality assessment. The Nature Conservancy was recently funded with $ 8 million by the
Moore Foundation to establish the ‘Osa Biological Corridor’, connecting several protected
areas on the Osa Pensinsula in southern Costa Rica, arguably the biologically richest
tropical rain forest in Central America (http://www.nature.org/pressroom/press/press1657.
html). Spending this money wisely depends on reliable assessment of the status of hitherto
unprotected forest remnants to be integrated into the prospective biological corridor.
One approach to assess the conservation status of forest remnants is the concept of
‘ecological continuity’ or, in more general terms, hemeroby or ‘naturalness’ (Rose 1974;
Norden and Appelquist 2001; Brentrup et al. 2002). Ecological continuity denotes the time
span a forest habitat requires to reach the successional stage of dynamic equilibrium: a
spatial-temporal mosaic of continuously changing patches (‘shifting mosaic’) representing
different successional stages, from young forest regrowth to mature forest (Heinselman
1973; Remmert 1991; Wu and Loucks 1995; Jentsch et al. 2002). Comprising the highest
diversity of mixed successional stages, the dynamic equilibrium supports higher species
1320 Biodivers Conserv (2008) 17:1319–1351
123
richness than younger and older successional stages (Connell 1978; Chesson 2000; Jentsch
et al. 2002; Wright 2002; Cunningham and Read 2003; Stokstad 2005); it is therefore the
‘preferred’ state of a forest ecosystem in terms of conservation. Mature forest patches are
the most critical components of this mosaic, since they require the entire time span to fully
develop. The temporal scale of ecological continuity has been suggested to be 200–500(-
1,000) years in temperate forests (Nilsson and Baranowski 1994; Gauslaa and Solhaug
1996; Hornberg et al. 1998), while examples such as the recovery of the Peten after the
Mayan deforestation (Rosenmeier et al. 2002), as well as age estimates based on tree
growth studies (Clark and Clark 2001; Laurance et al. 2004; Brienen 2005) indicate shorter
time spans of 100–500 years for tropical forests. Such time spans equal several human
generations, which has significant impact on conservation efforts, especially as clear-cut
and selective logging affect mature forest patches more than other components of the
mosaic.
Complete inventories of tropical rain forest stands to assess their ecological condition
are time- and resource-consuming and not feasible as routine implementations, although
Rapid Biological Inventories of plants and vertebrates (fm2.fieldmuseum.org/rbi) have
been successfully applied to establish protected areas, such as the Cordillera Azul National
Park in Peru (Alverson et al. 2001; http://www.fieldmuseum.org/cordilleraazul). Well-
studied Costa Rican rain forest stands harbour several thousand plant and vertebrate
species and a much higher number of invertebrates and fungi, such figures being the result
of several decades of study by hundreds of researchers (McDade et al. 1994; Kappelle
et al. 1996). Therefore, indirect methods such as remote sensing and bioindication by
surrogate species to assess the status of rain forest ecosystems have become popular
(Landres et al. 1988; Skole and Tucker 1993; Selva 1994, 1996, Ehrlich 1996; Faith and
Walker 1996a, 1996b; Cranston and Trueman 1997; De Leo and Levin 1997; Flather et al.
1997; Prendergast and Eversham 1997; Caro and O’Doherty 1999; Jonsson and Jonsell
1999; McCune 2000; Norden and Appelquist 2001; Sverdrup-Thygeson 2001; Whitfield
2001; Achard et al. 2002; Rose and Coppins 2002; Zedda 2004). Indicator species respond
to structural key factors that depend on ecological continuity, such as the diversity of
microhabitats for colonization, but also on the temporal component for successful dispersal
and establishment (Norden and Appelquist 2001).
Lichens have been successfully employed as bioindicators of environmental pollution
and ecosystem health in temperate regions (Hawksworth and Rose 1970, 1976; Nimis
1999; Insarov and Schroeter 2002; Nimis et al. 2002), including standardization using
models such as the Index of Atmospheric Purity (IAP; LeBlanc and De Sloover 1970) or
rigorous guidelines such as the German VDI 3957 for the use of lichens as bioindicators
(Bartholmess et al. 2004). Rose (1974) developed the Index of Ecological Continuity
(IEC), a measure of lichen species richness depending on ecological continuity, which was
later modified as ‘Revised’ (RIEC) and ‘New’ (NIEC) Index of Ecological Continuity
(Rose 1976, 1992; Selva 1994, 1996; Zedda 2004). The IEC or RIEC is a proportional
measure of species richness (n) relative to a predetermined ‘pool’ of 30 indicator species,
assuming that a maximum of 20 of these species occur at any given site (RIEC = 100
9 (n)/20). The use of this index and other measures of ecological continuity has been
criticised (Norden and Appelquist 2001), because of several reasons: (1) lack of stan-
dardization for comparison between geographical regions and different forest ecosystems;
(2) insufficient understanding of forest succession and its correlation with species richness;
(3) neglection of individual historical and ecogeographical factors influencing ecological
continuity for a given forest stand; (4) absence of solid ecological data for indicator
species; and (5) lack of quantitative methods of data sampling and analysis. Indicating
Biodivers Conserv (2008) 17:1319–1351 1321
123
ecological continuity thus requires careful selection of suitable bioindicators, knowledge of
their ecology, and a standardized, quantitative sampling approach. Suitable bioindicators of
ecological continuity increase in species richness and biodiversity with increasing eco-
logical continuity (reaching the dynamic equilibrium state), allow for easy quantitative
sampling, work across different forest ecosystems, and are widespread to be used in
different geographical regions. Also, a universal IEC index would ideally be independent
of ecogeographical constraints, in a similar manner as the IAP index.
Lichens are suitable bioindicators in tropical rain forests, since they form species-rich
communities on tree bark and leaves even in the forest understory, making them easily
accessible for observation and sampling (Sipman 1996; Gradstein et al. 1996; Lucking
2001). Rain forest lichen thalli are generally small (mostly less than 5 cm diam.) and
abundant, allowing for quantitative sampling with limited resources. Also, many species
are widely distributed. Lichens as bioindicators of environmental changes in the tropics
were used by Wolseley and her collaborators in Thailand (Wolseley and Aguirre-Hudson
1991, 1997a, 1997b; Wolseley et al. 1994; Wolseley 2002). In her study of montane
rainforests in Ecuador, Noske (2004) demonstrated the use of epiphytic lichens and bry-
ophytes as bioindicators of anthropogenic disturbances. In a more applied analysis, Peres
(2005) compared the lichen biota of three different forest management types in southern
Mexico and found that sustainable management conserved higher macrolichen diversity.
The dominant group of lichens in tropical rain forests are crustose microlichens, a
highly diverse assemblage that lacks detailed taxonomic and ecological studies, among
them the families Graphidaceae and Thelotremataceae (Wirth and Hale 1963, 1978; Hale
1974, 1978, 1981; Staiger 2002; Frisch et al. 2006). Hale (1974, 1978, 1981), in his
fieldwork in Central America, the Caribbean, and Sri Lanka, was the first to observe that
Thelotremataceae were diverse in undisturbed tropical rain forests but rare or absent in
strongly disturbed forests, as well as secondary and anthropogenic vegetation. He also
noticed that Thelotremataceae often colonize the trunks of large, mature trees, but are less
commonly found on young trees or on thin branches and twigs, observations that were
confirmed in recent studies in Venezuela, Cameroon, Tanzania and Brazil (Komposch and
Hafellner 1999, 2000; Kalb 2004; Frisch et al. 2006, Caceres et al. 2007a, 2007b). In the
present study, we test this hypothesis using a large dataset of 12,215 samples, gathered in
Costa Rica during the TICOLICHEN biodiversity inventory in 2002–2006 (Chaves et al.
2004; Lucking et al. 2004, 2007). The study is divided into two parts: In the first part, the
dataset was analysed with regard to six environmental parameters denoting habitat and
microhabitat preferences of 19 selected crustose corticolous microlichen families,
assuming that suitable indicators of ecological continuity show significant preferences for
closed, undisturbed (to partly disturbed or old growth secondary) forest, shaded micro-
habitats, and mature trees. In the second part, we tested the performance of
Thelotremataceae with respect to predicting forest disturbance levels, using richness
parameters, IEC, and related measures based on species, genus, and morphotype diversity.
Material and methods
We analysed a large dataset of specimens gathered at 115 different sites during the TI-
COLICHEN biodiversity inventory in Costa Rica (Lucking et al. 2004), collected between
2002 and 2006. The total number of specimens was close to 30,000, of which we selected
12,215 samples representing crustose, corticolous lichens belonging to the 19 most dom-
inant lichen families in this group in terms of abundance and genus and species diversity
1322 Biodivers Conserv (2008) 17:1319–1351
123
(Table 1). Crustose lichens were selected since the diversity and abundance of foliose and
fruticose macrolichens is comparatively low in tropical dry, moist, and lowland rain forest
habitats, especially in shaded conditions (Sipman and Harris 1989; Komposch and Ha-
fellner 2000). We tested and confirmed this observation by analysing the entire dataset of
nearly 30,000 samples first (data to be published elsewhere).
For each sample, we determined six environmental parameters (Table 2): (1) altitude,
(2) degree of seasonality, (3) vegetation type, (4) disturbance level, (5) substrate nature,
and (6) light exposure. Parameters (1)-(4) were site specific habitat parameters and
determined by consultation of vegetation maps and pertinent literature (Holdridge 1967;
Holdridge et al. 1971; Herrera 1985; Gomez 1986), as well as field observations and data
provided by the Costa Rican MINAE and SINAC (www. sinaccr.net). Parameters (5) and
(6) were sample specific microhabitat parameters and determined in the field using pre-
determined categories (Lucking 1997). Light exposure was estimated in five categories,
supported by semi-quantitative measurements using a fish-eye lens for hemispheric pho-
tographies mounted on a NIKON Coolpix 5400 digital camera.
Data were analysed in two ways: (1) Samples were categorized according to family and
parameter values and compared for significant differences across families using one-way
ANOVA and Scheffe post-hoc comparison. (2) The entire data matrix was subjected to
principal component analysis (PCA based on correlation matrix), to visualize the differ-
ential ordination of samples according to families (and genera of Thelotremataceae) in the
hyperspace defined by the six environmental parameters. All samples were analysed
simultaneously to result in a consistent ordination pattern, but families (and genera of
Thelotremataceae) were displayed individually to allow for easier comparison.
Table 1 Families of crustose,corticolous lichens analysed forthis study, indicating number ofgenera and species
Family Number ofgenera
Number ofspecies
Number ofsamples
Arthoniaceae 6 &50 927
Arthopyreniaceae 3 &10 89
Coenogoniaceae 1 &50 207
Graphidaceae 18 &200 3,275
Lecanoraceae 6 &40 741
Letrouitiaceae 1 &5 109
Monoblastiaceae 4 &35 152
Pertusariaceae 3 &25 626
Physciaceae 12 &50 689
Pilocarpaceae 16 &70 862
Porinaceae 4 &40 624
Pyrenulaceae 6 &65 925
Ramalinaceae 11 &50 680
Roccellaceae 13 &50 533
Strigulaceae 2 &10 64
Teloschistaceae 1 &10 87
Thelenellaceae 2 &10 35
Thelotremataceae 16 &130 1,129
Trypetheliaceae 10 &50 471
Total 135 &950 12,225
Biodivers Conserv (2008) 17:1319–1351 1323
123
In a subsequent approach, we analysed the 115 sampling sites for richness parameters of
Thelotremataceae and their correlation with observed disturbance categories. We excluded
25 sites lacking sufficient sampling effort, i.e. that were represented by a low number of
samples relative to the expected lichen species richness in the corresponding site class,
retaining 90 sites in the analysis. For each site, we determined the richness of species,
genera and morphotypes of Thelotremataceae. We defined 24 different morphotypes based
on apothecial and thallus morphology that can be readily determined using a hand lens,
without the aid of a compound microscope or chemical analysis (Fig. 1; Table 3). Modern
revisions of crustose lichens, in particular Graphidaceae and Thelotremataceae (Staiger
2002; Frisch et al. 2006; Lucking et al. 2007), demonstrate that groups of closely related
species share similar morphological traits and differ mainly in anatomical and chemical
characters. Specifically within a monophyletic lineage, the morphotype concept is thus a
good predictor of groups of related species and genera, and a good approximator to genus
and species richness, with the advantage of a significantly reduced effort in time and
resources with respect to identification work.
Since richness parameters are not only dependent on site quality but also site size, we
calculated a set of transformed richness values by dividing the number of species,
genera, and morphotypes, by the log-transformed number of samples for each site (as an
approximator for site size). Log-transformation is appropriate since richness parameters,
especially species richness, correlate with area in logarithmic fashion (Scheiner et al.
2000; Sagar et al. 2003; Scheiner 2003, 2004). In addition, we calculated relative
richness values based on species, genera, and morphotypes, as follows: the 115 sites
Table 2 Definition and coding of six environmental parameters used for the multivariate analysis ofcrustose lichen habitat and microhabitat ecology in Costa Rica
Category Code Category Code
Altitude Disturbance
sea level 1 undisturbed forest 1
0–200 m (lowland) 2 partly disturbed forest (selective logging) 2
200–500 m (submontane) 3 old growth secondary forest ([25 years) 3
500–1,000 m (lower montane) 4 young secondary forest (\25 years) 4
1,000–1,500 m (montane) 5 anthropogenic vegetation (plantations, gardens) 5
1,500–2,000 m (montane) 6 Substrate
2,000–2,500 m (upper montane) 7 trunk ([ 10 cm dbh) base (0–1 m) 1
2,500–3,000 m (upper montane) 8 lower trunk (1–5 m) or stem (\10 cm dbh) base 2
3,000–3,500 m (subparamo) 9 upper trunk ([5 m) or lower stem 3
Seasonality upper stem, branch ([2 cm), liana, stilt root 4
no dry season 1 twig (\2 cm) 5
slight dry season (\1 month) 2 wood (fence posts lacking bark) 6
distinct dry season (1–3 months) 3 Exposure
strong dry season (3–5 months) 4 fully shaded (0–2% diffuse site factor) 1
extended dry season ([5 months) 5 shaded (2–5 % diffuse site factor) 2
Vegetation semi-exposed (5–13% diffuse site factor) 3
Closed forest 1 exposed (13–35 % diffuse site factor) 4
Savanna (mixed forest and grassland) 2 fully exposed (35–100% diffuse site factor) 5
Grassland or shrub (including paramo) 3
1324 Biodivers Conserv (2008) 17:1319–1351
123
Fig. 1 Morphotypes in Thelotremataceae (see also Table 3). The cruentodiscoid, gyrotremoid, andrhodostromoid type are pigmented (yellow to red or pink pigments). For further explanation see text
Biodivers Conserv (2008) 17:1319–1351 1325
123
Table 3 Morphotypes of corticolous Thelotremataceae (see also Fig. 1)
Morphotype Apothecia and reproductivestructures
Thallus Genera
Chroodiscoid Open with recurved lobules smooth, ± shiny Acanthotrema, Chapsa
Leprocarpoid Open with erect lobules mealy, ± matt Chapsa
Cruentodiscoid Open with erect lobules discpigmented
smooth, ± shiny Chapsa
Gyrotremoid Open with recurved lobules,disc pigmented, withconcentric rings
smooth, ± shiny Gyrotrema
Reimnitzioid Open with erect lobules rough, with crystals Reimnitzia
Glaucescentoid Open with erect lobules rough, with crystals ‘‘Leucodecton’’ (glaucescens)
Leucodectonoid Closed with tiny pore rough, with crystals Leucodecton
Leptotremoid Immersed with small pore rough, with crystals Leptotrema
Myriotremoid Immersed with small pore smooth, ± shiny Myriotrema,‘‘Thelotrema’’glaucopallensgroup
Glaucophaenoid Prominent with wide pore, insection with pale walls
smooth, ± shiny Myriotrema
Annulotremoid Prominent with wide pore,pore with inner ring
smooth, ± shiny Myriotrema, Thelotrema
Thelotremoid Prominent with wide pore,pore with inner ‘‘mouth’’
smooth, ± shiny Thelotrema
Ampliotremoid Prominent with wide pore, insection with black walls
smooth, ± shiny Ampliotrema, Ocellularia
Ocellularioid Prominent with wide pore,pore with ‘‘finger’’(columella), in section withblack walls
smooth, ± shiny Ocellularia
Praestantoid Large and prominent withsmall pore, pore with‘‘finger’’ (columella), insection with black walls
smooth, ± shiny Ocellularia (praestans group)
Rhodostromoid Large and prominent withsmall pore, pore with‘‘finger’’ (columella), insection with black wallsand pigment
smooth, ± shiny Ocellularia (rhodostroma group)
Teniotremoid Immersed with small poreand black margin, porewith ‘‘finger’’ (columella),in section with black walls
smooth, ± shiny ‘‘Thelotrema’’clandestinumgroup
Melanotremoid Prominent with wide poreand black margin, porefilled with broad ‘‘stump’’(columella), in section withblack walls
smooth, ± shiny Melanotrema, Ocellularia,‘‘Thelotrema’’clandestinumgroup
Pallidostegoboloid Prominent with wide pore,pore filled with irregularstructures, in section withpale walls
smooth, ± shiny Stegobolus (wrightii group)
1326 Biodivers Conserv (2008) 17:1319–1351
123
were classified according to main environmental parameters (altitude, seasonality) into
six categories: (1) dry (semi-deciduous) forest (0–500 m), (2) moist (evergreen) forest
(500–1,500 m), (3) lowland rain forest (including submontane; 0–500 m), (4) lower
montane rain forest (500–1,000 m), (5) montane rain forest (1,000–2,000 m), and (6)
upper montane rain forest (including subparamo; 2,000–3,500 m). For each category, we
determined the total number of species, genera, and morphotypes. For species, we also
calculated the total number divided by the log-transformed number of sites included in
each category (since total species richness is logarithmically correlated with site num-
ber). Individual site richness values were then divided by the total numbers for each
category.
Based on the original IEC and revised RIEC indices (Rose 1974, 1976; Selva 1994,
1996; Zedda 2004), we calculated IEC indices for Thelotremataceae as follows:
IEC ¼ 100� n/Nmax;
where n = number of species, genera, or morphotypes, per site and Nmax = maximum
expected number of species, genera, or morphotypes, per site. Settings for Nmax were
derived from the data and adjusted with respect to site category and whether relating to
species, genus, or morphotype data (Table 4). The values for IEC range between 0 and
100% and were divided into five classes, using either as an approximated exponential or a
linear scale (Table 4). The highest IEC percentage thereby corresponded to the lowest
disturbance level, and vice versa.
Each of the three richness parameters and the IEC were tested for correlation with
observed disturbance categories for each site (see Table 2) using the Spearman rank
correlation. In addition, disturbance categories predicted from IEC indices based on
Thelotremataceae richness (Table 4) were compared to observed disturbance categories
using Spearman rank correlation.
Statistical analyses were performed using PC-ORD 5.03 (McCune and Mefford 1999;
McCune et al. 2002) and STATISTICATM 6.0.
Table 3 continued
Morphotype Apothecia and reproductivestructures
Thallus Genera
Stegoboloid Prominent with wide pore,pore filled with irregularstructures, in section withblack walls
smooth, ± shiny Stegobolus
Redingerioid Immersed with linear slit, slitfilled with irregularstructures, in section withblack walls
smooth, ± shiny Redingeria, Stegobolus
Isidiotremoid Apothecia lacking, with isidia smooth, ± shiny Myriotrema, Ocellularia
Schizotremoid Apothecia lacking, withschizidia
smooth, ± shiny Stegobolus
Sorediotremoid Apothecia lacking, withsoralia
smooth, ± shiny Myriotrema, Ocellularia
Biodivers Conserv (2008) 17:1319–1351 1327
123
Tab
le4
Set
tin
gs
for
Nm
ax
per
site
for
the
calc
ula
tio
no
fth
eIE
Cin
dic
esb
ased
on
Th
elo
trem
atac
eae
and
div
isio
no
fIE
Cv
alu
esin
tofi
ve
dis
turb
ance
clas
ses
Sit
eca
tegory
Dis
turb
ance
cate
gory
IEC
clas
s(e
xponen
tial
)S
pec
ies
Gen
era
Morp
hoty
pes
IEC
clas
s(l
inea
r)S
pec
ies
Gen
era
Morp
hoty
pes
Dry
fore
st(0
–5
00
m)
Nm
ax
–1
07
10
–1
07
10
1[
70
–10
0%
8–
10
5–
78
–1
0[
80
–10
0%
8–
10
6–
78
–1
0
2[
50
–70
%6
–7
46
–7
[6
0–
80
%6
–7
56
–7
3[
30
–50
%4
–5
34
–5
[4
0–
60
%4
–5
3–
44
–5
4[
10
–30
%2
–3
1–
22
–3
[2
0–
40
%2
–3
22
–3
50
–1
0%
0–
10
0–
10
–2
0%
0–
10
–1
0–
1
Mo
ist
fore
st(5
00
–1
,500
m)
Nm
ax
–1
07
10
–1
07
10
1[
70
–10
0%
8–
10
5–
78
–1
0[
80
–10
0%
8–
10
6–
78
–1
0
2[
50
–70
%6
–7
46
–7
[6
0–
80
%6
–7
56
–7
3[
30
–50
%4
–5
34
–5
[4
0–
60
%4
–5
3–
44
–5
4[
10
–30
%2
–3
1–
22
–3
[2
0–
40
%2
–3
22
–3
50
–1
0%
0–
10
0–
10
–2
0%
0–
10
–1
0–
1
Lo
wla
nd
rain
fore
st(0
–5
00
m)
Nm
ax
–2
01
01
2–
20
10
12
1[
70
–10
0%
15
–20
8–
10
9–
12
[8
0–
10
0%
15
–20
8–
10
11
–15
2[
50
–70
%1
1–
14
6–
77
–8
[6
0–
80
%1
1–
14
6–
78
–1
0
3[
30
–50
%7
–1
04
–5
4–
6[
40
–60
%7
–1
04
–5
5–
7
4[
10
–30
%3
–6
2–
32
–3
[2
0–
40
%3
–6
2–
32
–4
50
–1
0%
0–
20
–1
0–
10
–2
0%
0–
20
–1
0–
1
Lo
wer
mo
nta
ne
(50
0–1
,000
m)
Nm
ax
–1
57
10
–1
57
10
1[
70
–10
0%
11
–15
5–
78
–1
0[
80
–10
0%
15
–20
6–
78
–1
0
2[
50
–70
%8
–1
04
6–
7[
60
–8
0%
11
–14
56
–7
3[
30
–50
%5
–7
34
–5
[4
0–
60
%7
–1
03
–4
4–
5
4[
10
–30
%2
–4
1–
22
–3
[2
0–
40
%3
–6
22
–3
50
–1
0%
0–
10
0–
10
–2
0%
0–
20
–1
0–
1
1328 Biodivers Conserv (2008) 17:1319–1351
123
Ta
ble
4co
nti
nu
ed
Sit
eca
tegory
Dis
turb
ance
cate
gory
IEC
clas
s(e
xponen
tial
)S
pec
ies
Gen
era
Morp
hoty
pes
IEC
clas
s(l
inea
r)S
pec
ies
Gen
era
Morp
hoty
pes
Mo
nta
ne
(1,0
00–
2,0
00
m)
Nm
ax
–1
57
10
–1
57
10
1[
70
–10
0%
11
–15
5–
78
–1
0[
80
–10
0%
11
–15
6–
78
–1
0
2[
50
–70
%8
–1
04
6–
7[
60
–80
%8
–1
05
6–
7
3[
30
–50
%5
–7
34
–5
[4
0–
60
%5
–7
3–
44
–5
4[
10
–30
%2
–4
1–
22
–3
[2
0–
40
%2
–4
22
–3
50
–1
0%
0–
10
0–
10
–2
0%
0–
10
–1
0–
1
Up
per
mo
nta
ne
(2,0
00–
3,5
00
m)
Nm
ax
–1
05
7–
10
57
1[
70
–10
0%
8–
10
4–
55
–7
[8
0–
10
0%
8–
10
56
–7
2[
50
–70
%6
–7
34
[6
0–
80
%6
–7
45
3[
30
–50
%4
–5
23
[4
0–
60
%4
–5
33
–4
4[
10
–30
%2
–3
11
–2
[2
0–
40
%2
–3
22
50
–1
0%
0–
10
00
–2
0%
0–
10
–1
0–
1
Set
Nm
ax
val
ues
are
bas
edo
na
com
bin
atio
no
fm
axim
um
nu
mb
ero
fsp
ecie
s,g
ener
a,o
rm
orp
ho
typ
esp
ersi
teca
teg
ory
(gam
ma-
div
ersi
ty)
and
per
site
(alp
ha-
div
ersi
ty)
ob
serv
ed.
Fo
rlo
wla
nd
rain
fore
stsi
tes,
thes
eco
rres
po
nd
toN
max
defi
ned
for
tem
per
ate
fore
sts
inth
eo
rig
inal
IEC
(Ro
se1
97
4,
19
76;
Sel
va
19
94,
19
96;
Zed
da
20
04);
for
oth
ersi
tes,
val
ues
for
Nm
ax
are
low
ersi
nce
expec
ted
Thel
otr
emat
acea
ediv
ersi
tyis
low
er
Biodivers Conserv (2008) 17:1319–1351 1329
123
Results
Comparison of 19 families comprising tropical crustose lichens
Significant differences across families were found for all six environmental parameters.
Altitude divided the 19 families in four groups (Fig. 2): Group A included Pertusariaceae
Fig. 2 Column plot showing variation of altitude, seasonality, and vegetation categories according to lichenfamily. Groups A, B, C, and D are significantly different based on Scheffe post-hoc comparison. Indicatedare means and standard deviation. Altitude: 1 = sea level, 2 = 0–200 m, 3 = 200–500 m, 4 = 500–1,000 m,5 = 1,000–1,500 m, 6 = 1,500–2,000 m, 7 = 2,000–2,500 m, 8 = 2,500–3,000 m. Seasonality: 1 = no dryseason, 2 = slight dry season, 3 = distinct dry season, 4 = strong dry season, 5 = extended dry season.Vegetation: 1 = closed forest, 2 = savanna
1330 Biodivers Conserv (2008) 17:1319–1351
123
with preferential altitude of 1,000–2,000 m (montane), while group B (and transition to C)
comprised Arthopyreniaceae, Coenogoniaceae, Lecanoraceae, Ramalinaceae, and Thele-
nellaceae (preferential altitude 500–1,500 m: lower montane). Graphidaceae, Physciaceae,
Pilocarpaceae, Pyrenulaceae, Teloschistaceae, Thelotremataceae, and Trypetheliaceae,
form a third group C (with transition to D), with preferential altitudes of 200–1,000 m
(submontane to lower montane), and the fourth group D (0–500 m: lowland to submon-
tane) includes Arthoniaceae, Letrouitiaceae, Monoblastiaceae, Porinaceae, Roccellaceae,
and Strigulaceae.
Seasonality showed a similar pattern, with four groups (Fig. 2). Group A (with tran-
sition to B) included three families (Teloschistaceae, Physciaceae, Letrouitiaceae) with
preference for habitats with distinct to extended dry season. Group B (with transition to C)
comprised families with preference for rainforest with distinct dry season: Arthoniaceae,
Lecanoraceae, Monoblastiaceae, Porinaceae, Pyrenulaceae, Roccellaceae, and Trypethe-
liaceae. Group C (with transition to D) unites families with preference for rainforest with
slight (to distinct) dry season, including Arthopyreniaceae, Graphidaceae, Pertusariaceae,
Ramalinaceae, Strigulaceae, and Thelotremataceae, while three families belong to group D
(preference for rainforest with slight dry season): Coenogoniaceae, Pilocarpaceae, and
Thelenellaceae.
Except for Pertusariaceae, Lecanoraceae, and Trypetheliaceae (tendency towards
savanna vegetation), all families show a preference for closed forest vegetation (Fig. 2).
However, significant preferences for different disturbance levels were found (Fig. 3).
Arthoniaceae, Arthopyreniaceae, Coenogoniaceae, Graphidaceae, Lecanoraceae, Monob-
lastiaceae, Pertusariaceae, Physciaceae, Teloschistaceae, Thelenellaceae, and
Trypetheliaceae (group A including transition to B) showed preferences for secondary
forest and secondary vegetation, while five further families (Pilocarpaceae, Pyrenulaceae,
Ramalinaceae, Roccellaceae, Strigulaceae) were most commonly found in old growth
secondary forest. Only three families exhibited preferences for undisturbed to partly dis-
turbed primary and old growth secondary forest: Letrouitiaceae, Porinaceae, and
Thelotremataceae.
Analysis of substrate nature preferences revealed three groups (Fig. 3): Lecanoraceae,
Pertusariaceae, Physciaceae, and Teloschistaceae are more commonly found on trunks and
stems of young trees, as well as branches, twigs, and lianas, while Letrouitiaceae, Porin-
aceae, Pyrenulaceae, Ramalinaceae, Roccellaceae, Strigulaceae, Thelenellaceae, and
Thelotremataceae, are more characteristic of trunks of mature and old trees. The remaining
families (Arthoniaceae, Arthopyreniaceae, Coenogoniaceae, Monoblastiaceae, Pilocarpa-
ceae, and Trypetheliaceae) are intermediate in this respect. Light exposure preferences
across families revealed four groups (Fig. 3). Group A (with transition to B) included
families with preference for exposed microhabitats (Arthopyreniaceae, Lecanoraceae,
Physciaceae, Teloschistaceae, Trypetheliaceae), while families united in group B (with
transition to C) showed preferences for semi-exposed to exposed microhabitats (Arthon-
iaceae, Monoblastiaceae, Pertusariaceae, Thelenellaceae). Group C (with transition to D)
included families characteristic of semi-exposed microhabitats (Pilocarpaceae, Pyrenula-
ceae, Ramalinaceae), while the remaining families of group D preferred shaded to semi-
exposed microhabitats: Coenogoniaceae, Letrouitiaceae, Porinaceae, Roccellaceae, Stri-
gulaceae, and Thelotremataceae.
PCA ordination of the 12,215 specimen samples with respect to six environmental
parameters resulted in 68% cumulative variance explained on the first three axes and 50%
on the first and second axis (first axis eigenvalue = 1.74 or 29% variance, second axis
eigenvalue = 1.28 or 21% variance). The first axis correlated with the parameters light
Biodivers Conserv (2008) 17:1319–1351 1331
123
exposure and disturbance level and more weakly so with substrate nature and vegetation
type, while the second axis correlated strongly with altitude and negatively with of
seasonality (Fig. 4). Nine families showed indifference relative to the six measured
environmental parameters, being scattered across the hyperdimensional environmental
Fig. 3 Column plot showing variation of disturbance, substrate, and exposure categories according tolichen family. Groups A, B, C, and D are significantly different based on Scheffe post-hoc comparison.Indicated are means and standard deviation. Disturbance: 1 = undisturbed forest, 2 = partly disturbed forest(selective logging), 3 = old growth secondary forest, 4 = young secondary forest, 5 = anthropogenicvegetation. Substrate: 1 = trunk base, 2 = lower trunk, stem base, 3 = upper trunk or lower stem, 4 = upperstem, branch, liana, stilt root. Exposure: 1 = fully shaded, 2 = shaded, 3 = semi-exposed, 4 = exposed
1332 Biodivers Conserv (2008) 17:1319–1351
123
Fig. 4 PCA ordination of 12,215 specimen samples based on six environmental parameters; pointsindicating samples belonging six selected lichen families (all other sample points hidden)
Biodivers Conserv (2008) 17:1319–1351 1333
123
space: Arthoniaceae, Arthopyreniaceae (not shown), Graphidaceae (Fig. 4), Monoblasti-
aceae, Pyrenulaceae, Ramalinaceae, Strigulaceae, Thelenellaceae, and Trypetheliaceae
(not shown). Coenogoniaceae (Fig. 4) showed a tendency towards lowland and montane
habitats lacking a distinct to extended dry season. Four families exhibited a shift towards
exposed and disturbed (micro-)habitats, with slightly different behaviour regarding altitude
and seasonality: Lecanoraceae (Fig. 4) and Physciaceae (not shown) were indifferent with
regard to the latter, while Pertusariaceae (not shown) preferred montane and Teloschist-
aceae (not shown) dry habitats. Two families, Pilocarpaceae and Roccellaceae (not shown),
showed slight preferences towards shaded and undisturbed (micro-)habitats, while the
remaining three families exhibited a strong preference towards shaded and undisturbed
(micro-)habitats, with preference of lowland and drier habitats in Letrouitiaceae (Fig. 4),
slight preference of lowland (and drier) habitats in Porinaceae (Fig. 4) and altitudinal and
seasonality indifference in Thelotremataceae (Fig. 4).
Comparison of Thelotremataceae genera
Among Thelotremataceae, with a total of 1,129 samples, significant differences between
genera were found for altitude, degree of seasonality, vegetation type, disturbance level,
and exposure, while all genera agreed in substrate preferences towards the bark of mature
trees, mostly the lower and upper trunk (Fig. 5). Altitude revealed two opposing groups A
(1,000–1,500 m: Thelotrema) and C (0–500 m: Chapsa, Gyrotrema, Leucodecton), with
the remaining genera in between (Acanthotrema, Ampliotrema, Leptotrema, Myriotrema,Ocellularia, Stegobolus). Differences in seasonality were not as distinct but similarly
showed three groups, with Leucodecton showing preferences towards habitats with distinct
to strong dry season and Thelotrema exhibiting tendencies towards habitats with no or a
slight dry season only. All genera prefer closed forest, with only Thelotrema showing a
tendency towards savanna or paramo shrub. Leucodecton was the only genus with pref-
erences towards secondary vegetation, while the remaining genera either preferred
undisturbed to partly disturbed forest (Acanthotrema, Ampliotrema, Gyrotrema, Stegobo-lus) or partly disturbed to old growth secondary forest (Chapsa, Leptotrema, Myriotrema,Ocellularia, Thelotrema). In accordance, slight differences were found with regard to light
exposure, with Leucodecton, Ampliotrema, Myriotrema, and Thelotrema, preferring semi-
exposed and the remaining genera (Acanthotrema, Chapsa, Gyrotrema, Leptotrema,Ocellularia, and Stegobolus) shaded microhabitats.
Nine genera, comprising 80% of all Thelotremataceae samples, show strong preference
for shaded and undisturbed (micro-)habitats, with indifference regarding altitude and
seasonality, thus following the general pattern of the family. These are Acanthotrema,Ampliotrema, Chapsa (Fig. 6), Leptotrema, Myriotrema (not shown), Ocellularia (Fig. 6),
Reimnitzia, and Stegobolus (Fig. 6). Five further genera also show strong preference for
shaded and undisturbed (micro-)habitats, but with distinct preferences towards lowland
habitats in Gyrotrema (Fig. 6), and montane habitats in Fibrillithecis, Melanotrema,Redingeria (not shown), and Thelotrema (Fig. 6). The Thelotrema clandestinum group
shows a montane distribution with indifference regarding exposure and disturbance
(Fig. 6), whereas Leucodecton (Fig. 6) prefers shaded and undisturbed (micro-)habitats in
lowland forests and more exposed and disturbed (micro-)habitats in montane forests. Thus,
only two of the 16 genera are indifferent with respect to exposure and disturbance.
Morphotype data (not shown) gave similar results, with the exception of the cruento-
discoid morphotype tending towards exposed and disturbed lowland (micro-)habitats, the
1334 Biodivers Conserv (2008) 17:1319–1351
123
isidiotremoid morphotype showing a montane distribution with indifference regarding
exposure and disturbance (similar to that of the Thelotrema clandestinum group), and the
tenuitremoid morphotype preferring montane shaded and undisturbed (micro-)habitats
(similar to Thelotrema).
Fig. 5 Column plot showing variation of altitude, seasonality, vegetation, disturbance, substrate, andexposure categories according to 10 selected genera of the lichen family Thelotremataceae. Groups A, B,and C are significantly different based on Scheffe post-hoc comparison. Indicated are means standarddeviation. Altitude: 1 = sea level, 2 = 0–200 m, 3 = 200–500 m, 4 = 500–1,000 m, 5 = 1,000–1,500 m,6 = 1,500–2,000 m, 7 = 2,000–2,500 m, 8 = 2,500–3,000 m. Seasonality: 1 = no dry season, 2 = slight dryseason, 3 = distinct dry season, 4 = strong dry season, 5 = extended dry season. Vegetation: 1 = closedforest, 2 = savanna. Disturbance: 1 = undisturbed forest, 2 = partly disturbed forest (selective logging),3 = old growth secondary forest, 4 = young secondary forest, 5 = anthropogenic vegetation. Substrate:1 = trunk base, 2 = lower trunk, stem base, 3 = upper trunk or lower stem, 4 = upper stem, branch, liana,stilt root, 5 = twig. Exposure: 1 = fully shaded, 2 = shaded, 3 = semi-exposed, 4 = exposed
Biodivers Conserv (2008) 17:1319–1351 1335
123
Fig. 6 PCA ordination of 12,215 specimen samples based on six environmental parameters; pointsindicating samples belonging to six selected genera of the lichen family Thelotremataceae (all other samplepoints hidden)
1336 Biodivers Conserv (2008) 17:1319–1351
123
Thelotremataceae as predictors of disturbance
Analysis of Thelotremataceae richness parameters of the 115 sites resulted in strong and
highly significant (P \ 0.001) negative correlations with observed disturbance categories,
with Spearman correlation coefficients ranging between -0.69 and -0.80 (not shown).
Excluding the 25 sites with insufficient sampling effort, Spearman correlation coefficients
increased to -0.80 to -0.84, with minor differences between individual parameters
(Table 5). Equally strong negative correlations (-0.83 to -0.84) were found for richness
(Fig. 7), richness divided by log-transformed sample number, and IEC (Fig. 7), while
richness divided by total richness per site category, as well as species per genus quotient,
showed slightly weaker correlations (-0.80 to -0.82). In all cases, species, genus, and
morphotype data performed equally well.
Richness parameters and IEC performed differently depending on site category. Very
strong and highly significant negative correlations (-0.88 to -0.99) were observed for dry
forest, lowland rain forest, and montane sites (Table 5), with all parameters performing
similarly well. In dry forest sites, species data performed better than genus and morphotype
data, whereas in lowland rainforest sites it was genus data and in montane sites it was
morphotype data, but the differences were very minor (1–2% points). Upper montane sites
showed a similar pattern but with weaker negative correlations (-0.60 to -0.61). Moist
forest and lower montane sites behaved erratically, with mostly weak negative correlations
lacking statistical significance, except for genus data in the case of lower montane sites
(Table 5).
We observed very strong and highly significant positive correlations between predicted
(based on IEC) and observed disturbance categories for all sites together and for dry,
lowland rain forest, and montane sites, ranging between +0.82 and +1.00 (Tables 5 and 6).
Upper montane sites showed slightly weaker correlations (+0.61 to +0.78), while those for
moist forest and lower montane sites were generally weak, although mostly significant.
Best overall performance was found for species data in combination with exponentially
defined IEC categories, but individual differences were apparent: dry forest sites did not
differ markedly with respect to exponentially or linearly defined categories (except for
genus data), while exponentially defined categories gave stronger correlations for species
(and morphotype) data in dry forest, lowland rain forests, and montane sites, and for genus
data in montane rain forests (Table 5). In contrast, linearly defined categories gave better
results based on genus data overall and in dry, moist, lowland rain forest, lower montane,
and upper montane sites, and based on morphotype data in dry forest, lower montane,
montane, and upper montane sites.
In terms of accuracy with respect to prediction of disturbance categories, species,
genus, and morphotype data performed better in combination with exponentially defined
categories (Fig. 8). Thus, while correlations were partially stronger for genus and mor-
photype data in combination with linearly defined categories, predictive accuracy was
lower. In particular, observed disturbance categories 2, 3, and 4, tended to be underes-
timated as categories 3, 4, and 5, especially for species data (Fig. 8). For species data
and exponentially defined IEC categories, prediction was accurate for disturbance cate-
gories 1, 2, and 5, whereas slight deviations were observed for categories 3 and 4,
respectively (Table 6). In category 3, one sites was wrongly predicted as category 5,
whereas in category 4, almost half of the sites were wrongly predicted as category 5.
Also, one out of 46 sites in category 5 was wrongly predicted as category 2. Except for
this site and another in category 4, inaccurate predictions resulted in underestimations of
Biodivers Conserv (2008) 17:1319–1351 1337
123
Tab
le5
Lin
ear
rank
corr
elat
ion
(rS
pearm
an)
bet
wee
nri
chnes
spar
amet
ers,
IEC
index
,an
dpre
dic
ted
dis
turb
ance
cate
gori
esbas
edo
nth
efa
mil
yT
hel
otr
emat
acea
ew
ith
obse
rved
dis
turb
ance
cate
gori
es(s
eeal
soF
ig.
7).
Ab
sen
ceo
fsi
gn
ifica
nt
P-l
evel
sw
ith
stro
ng
corr
elat
ion
sin
low
eran
du
pp
erm
on
tane
rain
fore
star
ed
ue
tolo
wsi
ten
um
ber
s(4
–7
)
Sit
ese
lect
ion
:A
ll(9
0)
Dry
(7)
Mo
ist
(13
)L
ow
lan
d(2
6)
Lo
wer
(6)
Mo
nta
ne
(27
)U
pp
er(1
1)
r Spearm
an
Pr S
pearm
an
Pr S
pearm
an
Pr S
pearm
an
Pr S
pearm
an
Pr S
pearm
an
Pr S
pearm
an
P
Ric
hn
ess
Sp
ecie
s-
0.8
4*
**
-0
.97
**
*-
0.3
9–
-0
.90
**
*-
0.5
9–
-0
.98
**
*-
0.6
1*
Gen
era
-0
.84
**
*-
0.9
6*
**
-0
.39
–-
0.9
1*
**
-0
.81
*-
0.9
7*
**
-0
.61
*
Mo
rph
oty
pes
-0
.84
**
*-
0.9
6*
**
-0
.39
–-
0.9
0*
**
-0
.59
–-
0.9
9*
**
-0
.61
*
Ric
hn
ess
div
ided
by
log
-tra
nsf
orm
edsa
mp
len
um
ber
Sp
ecie
s-
0.8
3*
**
-0
.96
**
*-
0.4
1–
-0
.88
**
*-
0.5
9–
-0
.99
**
*-
0.6
1*
Gen
era
-0
.84
**
*-
0.9
6*
**
-0
.41
–-
0.8
8*
**
-0
.80
–-
0.9
7*
**
-0
.61
*
Mo
rph
oty
pes
-0
.84
**
*-
0.9
6*
**
-0
.41
–-
0.8
8*
**
-0
.59
–-
0.9
9*
**
-0
.61
*
Ric
hn
ess
div
ided
by
tota
lri
chn
ess
for
site
clas
s,in
clu
din
gco
rrec
tio
nfo
rsp
ecie
sb
ylo
g-t
ran
sfo
rmed
site
nu
mb
er
Sp
ecie
s-
0.8
0*
**
-0
.97
**
*-
0.3
9–
-0
.90
**
*-
0.5
9–
-0
.98
**
*-
0.6
1*
Sp
ecie
s(c
orr
ecte
d)
-0
.82
**
*-
0.9
7*
**
-0
.39
–-
0.9
0*
**
-0
.59
–-
0.9
8*
**
-0
.61
*
Gen
era
-0
.81
**
*-
0.9
6*
**
-0
.39
–-
0.9
1*
**
-0
.81
*-
0.9
7*
**
-0
.61
*
Mo
rph
oty
pes
-0
.81
**
*-
0.9
6*
**
-0
.39
–-
0.9
0*
**
-0
.59
–-
0.9
9*
**
-0
.61
*
Sp
ecie
sp
erg
enu
sq
uo
tien
t
Qu
oti
ent
-0
.81
**
*-
0.7
4–
-0
.39
–-
0.8
7*
**
-0
.28
–-
0.9
6*
**
-0
.60
–
IEC
calc
ula
ted
as1
00
9(n
)/N
max
Sp
ecie
s-
0.8
4*
**
-0
.97
**
*-
0.3
9–
-0
.90
**
*-
0.5
9–
-0
.98
**
*-
0.6
1*
Gen
era
-0
.84
**
*-
0.9
6*
**
-0
.39
–-
0.9
1*
**
-0
.81
*-
0.9
7*
**
-0
.61
*
Mo
rph
oty
pes
-0
.84
**
*-
0.9
6*
**
-0
.39
–-
0.9
0*
**
-0
.59
–-
0.9
9*
**
-0
.61
*
Pre
dic
ted
(bas
edon
IEC
)vs.
obse
rved
dis
turb
ance
cate
gory
(exponen
tial
lydefi
ned
cate
gori
es)
Sp
ecie
s+
0.8
7*
**
+1
.00
**
*+
0.5
7*
+0
.93
**
*+
0.4
9–
+0
.92
**
*+
0.7
8*
Gen
era
+0
.82
**
*+
0.9
1*
+0
.39
–+
0.8
3*
**
+0
.81
*+
0.9
7*
**
+0
.61
*
Mo
rph
oty
pes
+0
.85
**
*+
0.9
9*
**
+0
.57
*+
0.9
2*
**
+0
.49
–+
0.9
1*
**
+0
.61
*
1338 Biodivers Conserv (2008) 17:1319–1351
123
Ta
ble
5co
nti
nu
ed
Sit
ese
lect
ion
:A
ll(9
0)
Dry
(7)
Mo
ist
(13
)L
ow
lan
d(2
6)
Lo
wer
(6)
Mo
nta
ne
(27
)U
pp
er(1
1)
r Spearm
an
Pr S
pearm
an
Pr S
pearm
an
Pr S
pearm
an
Pr S
pearm
an
Pr S
pearm
an
Pr S
pearm
an
P
Pre
dic
ted
(bas
edon
IEC
)vs.
obse
rved
dis
turb
ance
cate
gory
(lin
earl
ydefi
ned
cate
gori
es)
Sp
ecie
s+
0.8
2*
**
+0
.99
**
*+
0.5
7*
+0
.87
**
*+
0.5
6–
+0
.82
**
*+
0.7
8*
Gen
era
+0
.85
**
*+
0.9
9*
**
+0
.57
*+
0.8
9*
**
+0
.90
*+
0.9
0*
**
+0
.78
*
Mo
rph
oty
pes
+0
.85
**
*+
1.0
0*
**
+0
.57
*+
0.8
8*
**
+0
.72
–+
0.9
2*
**
+0
.78
*
*S
ign
ifica
nt
**
*H
igh
lysi
gn
ifica
nt
Biodivers Conserv (2008) 17:1319–1351 1339
123
disturbance categories, i.e. sites were predicted as more strongly disturbed than observed
in the field (Table 6).
Discussion
This study is the first to analyse a large dataset of tropical crustose, corticolous microli-
chens in terms of their habitat and microhabitat preferences. In addition to the large
number of samples analysed, the study covers 19 families of crustose, corticolous, tropical
lichens, with a total of 135 genera and approximately 950 species, corresponding to
Fig. 7 Boxplots showing correlation between species, genus, and morphotype richness and observeddisturbance category, as well as between IEC based on species, genera, and morphotypes and observeddisturbance category. Indicated are means, standard deviation, and min/max
1340 Biodivers Conserv (2008) 17:1319–1351
123
Fig. 8 Boxplots showing correlation between predicted category based on species, genera, andmorphotypes and observed disturbance category, using either exponential or linear scaling. Indicated aremeans, standard deviation, and min/max
Table 6 Observed versus predicted disturbance categories derived from IEC based on species data andexponential scaling of transformation of IEC values into five classes
Observed category Number of sites analysed Predicted category
1 2 3 4 5
1. Undisturbed 8 7 1 – – –
2. Partly disturbed 11 – 9 2 – –
3. Old growth secondary 6 – – 4 1 1
4. Young secondary 19 – – 1 9 9
5. Anthropogenic 46 – 1 – – 45
Total 90 7 11 7 10 55
Biodivers Conserv (2008) 17:1319–1351 1341
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roughly 90% of crustose, corticolous lichen species occurring in Costa Rica. The formation
of different lichen communities under different light levels, and their stratification from the
shaded rain forest understory to the exposed canopy (Cornelissen and Ter Steege 1989;
Montfoort and Ek 1990; Lucking 1998, 1999; Komposch and Hafellner 2000, 2003; Holz
and Gradstein 2005) is the principal explanation for changes in lichen diversity and species
composition in partly disturbed and secondary forests and secondary and anthropogenic
vegetation (Lucking 1997). Accordingly, in our PCA ordination of the specimen data, the
two parameters light exposure and disturbance level were highly redundant. Disturbances
such as selective logging that change the canopy structure alter light regimes in the
understory (Chazdon and Fetcher 1984; Smith et al. 1992; Turton 1992; Clark et al. 1996;
Sterck 1997; Sterck et al. 1999), but also reduce tree fall gap dynamics (Hartshorn 1978;
Denslow 1987; McDade et al 1994), which initially leads to higher light levels and
extensive gaps in the understory, but eventually to stands with a more uniformly shaded
understory under a closed canopy composed of demographically more homogeneous,
younger trees. Initial disturbance thus favors lichen communities adapted to higher light
levels, while subsequent phases developing into old growth secondary forest favor com-
munities adapted to low light levels. As a result, lichens of different communities will have
difficulties to coexist, and lichens characteristic of mature tree trunks will disappear.
Abundance, diversity and species composition of such lichens are therefore a good pre-
dictors of ecological continuity, reflecting the recent disturbance history of a given forest
plot.
In the present study, three out of 19 families showed (micro-)habitat preferences that
meet the requirements of potential indicators of ecological continuity: Letrouitiaceae,
Porinaceae, and Thelotremataceae. All other families are either indifferent with respect to
the analysed environmental parameters or show a reverted tendency: Lecanoraceae,
Pertusariaceae, Physciaceae, and Teloschistaceae are more characteristic of exposed, dis-
turbed habitats, a behaviour also observed in other studies (Komposch and Hafellner 2000,
2003; Caceres et al. 2007a). The taxonomic diversity of Letrouitiaceae and Porinaceae is
significantly lower compared to Thelotremataceae (Letrouitiaceae one genus: Letrouitia;
Porinaceae one dominant rain forest genus: Porina), and their preferred altitudinal range is
narrower. Thus, quantitative models working with index values based on genus and species
richness will not perform well. This leaves Thelotremataceae as the best bioindicator of
ecological continuity in tropical rain forests, supporting observations made by Hale (1974,
1978, 1981) and our initial hypothesis. Indeed, our analysis of different richness param-
eters and indices based on Thelotremataceae show strong and highly significant
correlations with disturbance level, provided that data are based on sufficient sampling
effort.
Richness parameters (species, genus, and morphotype number) and IEC correlate
equally well with observed disturbance categories, due to the fact that richness and IEC
are directly proportional as long as observed values for n are not greater than Nmax. The
advantage of the IEC is that Nmax can be adjusted to allow for comparison between
different forest ecotypes, as shown here for dry forest, lowland rain forest, and montane
rain forest habitats. The subjective determination of Nmax is one of the elements of the
IEC that is to be criticised (Norden and Appelquist 2001), but the alternative calculation
of derived richness parameters relativized by total sample, total species, or total site
number, as tested here, did not give improved results and instead even performed worse
than the IEC. A remarkable finding is the strong correlation of species and genus
richness data, based on taxonomic identifications by experienced workers or specialists,
with morphotype data, the latter based on simple morphological assessment. The
1342 Biodivers Conserv (2008) 17:1319–1351
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performance of morphotype data did not differ from that of species data, thus allowing
for developing an index that works with morphotypes rather than taxa, being suitable for
a much wider group of potential users. In addition, rapid assessments in the field are
feasible. Also, morphotype data are not susceptible to taxonomic changes and yet better
predictors of systematic relationships than previously assumed (Staiger 2002; Frisch
et al. 2006). Apart from their ecological traits, Thelotremataceae are suitable for this
approach: with a few exceptions, they are readily separated as a group from most other
crustose lichen families that occur in the same habitats (except for a few Graphidaceae
and rare Gomphillaceae, Gyalectaceae, and Stictidaceae), and they exhibit sufficient
morphological variation.
Deviations from the overall pattern of observed versus predicted disturbance cate-
gories were found in the moist and lower montane rain forest. The moist forest sites
showed rather accurate predictions except for one site, the Leonelo Oviedo Ecological
Reserve on the campus of the University of Costa Rica in the capital San Jose (Di
Stefano et al. 1996; http://www.biologia.ucr.ac.cr/estaciones.html#LO). Structurally and
historically, the site classifies as category 3 (old growth secondary forest), but the
presence of only one Thelotremataceae predicts category 5. This is most probably due to
the fact that the vast majority of the surrounding, heavily populated Central Valley is
completely deforested (Sanchez-Azofeita et al. 2001). Thus, recolonization by Thelotr-
emataceae (and other lichens typical of closed forest) is difficult, if not impossible, even
if the ecological conditions would support their growth. Another case is a pasture at
Volcan Tenorio National Park, a lower montane rain forest site, bordered by living
fences of planted, young trees surrounding pasture grazed by cows. Such landscapes are
common in Costa Rica and exhibit low Thelotremataceae diversity, with 0–1(-2) genera
and species. However, the mentioned site supported no less than nine species in four
genera, predicting a category 2 (partly disturbed primary forest). Volcan Tenorio forms
part of an ecologically unique region characterized by constant cloud cover and drizzling
rain to below 1,000 altitude, which even for exposed vegetation results in conditions that
support unusually high lichen diversity. These outliers are the reason for the low cor-
relations observed for moist and lower montane rain forest and point out two conditions
which relativize the usefulness of richness values and IEC: (1) spatial isolation and
fragmentation which significantly affect dispersal from source sites, and (2) specific
ecological conditions that deviate from overall patterns of observed ecotypes. In such
cases, predictions of disturbance levels might not work, but the combination of observed
structure and IEC will give insight into particular geographical, historical, or ecological
conditions.
Data on Thelotremataceae richness and site disturbance levels are available from a
few other studies, particularly Hale (1974, 1978, 1981) in Panama, Dominica, and Sri
Lanka, but also Komposch and Hafellner (2000, 2003) in Venezuela and Caceres et al.
(2007a, 2007b) in northeastern Brazil. In all cases, Spearman rank correlations show
strong, significant negative correlations between Thelotremataceae species richness and
disturbance category and positive correlations between observed and predicted distur-
bance category, when IEC is calculated for each site applying the same settings as in this
paper (Table 7). However, accuracy of predictions varies, as do maximum species
numbers per site. In Panama and Sri Lanka, Hale (1974) found up to 44 species per site,
twice as many as in the present study for Costa Rican sites. This is in part due to the fact
that Hale extensively sampled canopy species, which may account for more than 50% of
species richness at a given site (based on our observations on Hale’s collected material at
US). Komposch and Hafellner (2000) found 69 species of Thelotremataceae at a single
Biodivers Conserv (2008) 17:1319–1351 1343
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site in Venezuela, out of a total of 250 lichen species; however, most of these were from
the upper trunk and inner canopy region, and only seven species were sampled at the
trunk base. Extensive canopy sampling was not done in the present study and is also not
feasible for the purpose of monitoring; accordingly, reducing Hale’s numbers by 50% (at
sites with extensive canopy sampling) yields figures similar to those found in the present
study. Also, sample sites were much more narrowly defined in the present study, to
maintain closely adnate sites with different disturbance history separate, which also
accounts for lower per site richness compared to Hale (1974, 1978, 1981). Yet, even
without correction for canopy samples and site definition, prediction of disturbance
categories is rather accurate based on Hale’s data, with only three out of 12 sites
predicting a lower disturbance level than observed.
The numbers reported by Hale (1978) for Dominica range between 1 and 21, very
similar to the present study. However, predictions are not as accurate, especially in
observed category 2 (13 sites), with four sites predicted as category 3 and 5 sites as
category 4 when using the settings given in this paper. These underestimations can be
explained by three reasons. Firstly, several of the sites were only briefly sampled, recov-
ering only part of the entire species richness. Secondly, the studied mountain ranges on
Dominica are rather low, reaching little less than 1,200 m altitude, which causes a mass
elevation effect that lowers altitudinal zones (Hastenrath 1968; Grubb 1971). As a con-
sequence, forest in a range of 800–1,200 m, in Costa Rica considered lower montane to
montane, on Dominica ecologically behaves like an upper montane rain forest (elfin for-
est), which requires a correction of Nmax. For example, a category 2 site at 1,200 m had six
species, which would result in a predicted category 3 if considered a montane site, but
category 2 (as observed) if considered an upper montane site due to the mass elevation
effect. Thirdly, Dominica, as an island ecosystem, was mostly colonized by long-distance
dispersal, which results in lower species richness than expected in similar mainland forest
ecotypes. In northeastern Brazil, ten sites of observed category 2 (partly disturbed) are
consistently underestimated as categories 3, 4, and 5. The Atlantic rain forest, especially its
northeastern part, is highly fragmented into small, partly disturbed rain forest remnants
isolated by large agricultural and urban areas (Whitmore 1990; Silva Filho et al. 1998),
which possibly affects diversity of species dependent on undisturbed primary forest beyond
Table 7 Thelotremataceae species richness and observed versus predicted disturbance categories (appyingsettings as in present paper) based on raw data from studies in Panama, Dominica, Sri Lanka, Venezuela,and northeastern Brazil (Hale 1974, 1978, 1981; Komposch and Hafellner 2000; Caceres et al. 2007a,2007b)
Study Numberof sites
Max. speciesrichness per site
Species richness vs.observed disturbance
Predicted vs.obs. disturbance
Costa Rica (this paper) 90 19 -0.84** +0.87**
Panama (Hale 1974) 12 34CAN -0.81* +0.90**
Dominica (Hale 1978) 28 21CAN -0.81** +0.76**
Sri Lanka (Hale 1981) 15 44CAN -0.75** +0.74**
Venezuela (Komposchand Hafellner 2000)
1 69CAN – –
NE Brazil (Caceres et al. 2007a) 23 15 -0.80** + 0.67**
* = Significant (P \ 0.05), ** = Highly significant (P \ 0.001)CAN = Denotes that extensive upper trunk and canopy sampling took place
1344 Biodivers Conserv (2008) 17:1319–1351
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the observed disturbance level, due to difficulties in dispersal and paucicity of undisturbed
source areas. Also, part of the sites represents the dry Caatinga, to which the Nmax setting
of dry forest (10 species) was applied, but which might have much lower genuine species
richness.
These data support the strong negative correlation between Thelotremataceae species
richness and disturbance level across a wide geographical range in the tropics and across
a wide range of forest ecotypes, but also emphasize that, for accurate prediction of
disturbance levels, both a uniform and standardized sampling protocol and adjustment of
the IEC to forest ecotype and to particular geographical and ecological conditions are
required, taking into account phenomena such as the mass elevation effect and island
biogeography. While this sounds complex, the only parameter that needs to be adjusted
is Nmax, and for this purpose, quantitative ecological data are required for a wider
geographic range.
Based on these findings, we formulate recommendations for the use lichens as bioin-
dicators of ecological continuity in tropical forest ecosystems: (a) The selected organisms
must exhibit a monotonous, negative relationship with disturbance level. For crustose
corticolous lichens (dominant in lowland rain forest), three families meet this requirement:
Letrouitiaceae, Porinaceae, and Thelotremataceae. (b) The selected organisms must have
sufficiently high taxonomic diversity at genus and species level. Among the three afore-
mentioned families, only Thelotremataceae meet this condition. (c) Abundance and
diversity should be high across a wide geographic range and across different forest eco-
types. Thelotremataceae show a wide range regarding altitude and seasonality, but work
best in dry to wet lowland to montane forest ecosystems. For more extreme forest ecotypes
and other ecosystems, other lichen groups are more feasible. (d) For studies of relative
comparison between sites, determination of simple richness values (number of species,
genera, morphotypes) suffice, but comparison with other studies and standardization of
findings is strongly limited. Instead, a standardized, adjustable IEC should be used. (e)
Alternative indices, relativizing richness values against total number of samples, taxa, or
sites, do not perform better, and partly worse, than the IEC. The IEC, a richness measure
relative to total expected site richness, is the simplest and best approach to calculate a
standardized, comparable index. (f) The most critical element of the IEC is the setting of
Nmax, which has to be adjusted to forest ecotype, including a number of ecological
parameters such as precipitation regime and physiognomy, rather than simply altitude
(mass elevation effect). Tree species composition, on the other hand, does not seem to
affect the behaviour of Thelotremataceae richness, as shown by comparison of data from
different parts of the Neotropics and those of Sri Lanka, which all share similar rain forest
physiognomies but different tree species, genera, and even families. (g) Besides species
and genus data, morphotype data are a viable alternative to calculate the IEC. The effort in
time and resources is roughly 5–10% of the effort when identifying species, and direct
assessments in the field are possible, which surpasses the disadvantage of inaccurate
taxonomic treatment, especially as morphotype data perform as well as species data in the
prediction of disturbance levels. (h) A standardized sampling protocol is required. Based
on our experiences in Costa Rica (Lucking et al. 2004, 2007), as well as in southern and
northeastern Brazil (Marcelli 1992; Caceres et al. 2007c), Venezuela (Komposch and
Hafellner 2000) and on published sampling protocols (Gradstein et al. 1996; Sipman
1996), including those using lichens as bioindicators of atmospheric pollution (Kirschbaum
and Wirth 1997; Nimis et al. 2002; Bartholmess et al. 2004), we propose a preliminary
protocol to be tested by further studies (Box 1).
Biodivers Conserv (2008) 17:1319–1351 1345
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Acknowledgements This study was made possible by grants from the NSF to The Field Museum (DEB0206125; PI R. Lucking/DEB 0516116; PI H. T. Lumbsch, CoPI R. Lucking). Most of the Thelotremataceaematerial and other crustose lichens analysed in this study were collected by R. Lucking, J. L. Chaves, and H.J. M. Sipman, but collections and field data were also contributed by A. Aptroot, W. R. Buck, E. Fletes, M.Grube, I. Lopez, E. Navarro, M. P. Nelsen, M. T. Trest, L. Umana, and S. Will-Wolf. We thank INBio andthe Costa Rican MINAE and SINAC for assistance with working and collection permits.
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2. Establish a transect of 500 m length.
3. Select 50 trees each 10 m along the transect.
4. For each tree, (a) either collect a sample of each presumed Thelotremataceae thallus from ground level to2 m height all around the trunk, for subsequent identification to morphotype, genus, or species level, or(b) record the presence of different Thelotremataceae morphotypes as defined here from ground level to2 m height all around the trunk directly in the field, preferably supported by digital images for subsequentconfirmation.
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