Composition & Diversity

A total of 247 and 190 species were recorded in the ≥5 cm and ≥10 cm diameter classes of the study respectively, distributed among 89 and 76

5 _{All soil analyses were conducted at the Soil, Plant, Water and Fertilizer Analysis Laboratory,} Department of Soils, Faculty of Agronomy, Universidad Nacional Agraria La Molina in Lima, Peru

6 _{Analyses conducted using the Walkey & Black method}

7 _{Analyses conducted using the CIC method}

genera and 47 and 40 families (see Appendix D). Over 50% of the species, genera and families recorded were present at the leeward forest (Figure 3.3.1.1), which also presented the highest family, genus and species richness in both diameter classes (Table 3.3.1.1), while the windward forest presented slightly greater general richness than the ridge forest, with the same trend applying to sub-plot species richness.

In both diameter classes, the species richness of sub-plots was significantly higher at the leeward site (P = 0.001). The leeward forest showed the greater diversity index scores in both diameter classes, followed by the ridge and windward forests (Table 3.3.1.1). The Podocarpaceae, the only gymnosperm family, was best represented at the windward forest, while the Cyatheaceae was the only pteridophyte family and best represented at the leeward forest (Table 3.3.1.1). While the leeward forest had the largest number of species with very low abundance or sub-plot frequency (Table 3.3.1.1), the proportions were similar among forests (Figure 3.3.1.2).

Table 3.3.1.1: General floristic and structural statistics from the leeward, ridge and windward forest 1-ha plots.

DBH ≥5cm DBH ≥10cm

Description Lee Ridge Wind Lee Ridge Wind

Species/ha 136 74 81 109 51 59 Genera/ha 61 37 44 56 28 35 Families/ha 34 27 28 31 22 23 Angiosperm N sp. 130 71 76 103 48 54 Gymnosperm N sp. 1 2 3 1 2 3 Pteridophytes N sp. 5 1 2 5 1 2 Aver. species/400m2 _{26.5 21.0 22.1 16.3 9.7 10.8}

Live stem density/ha 1013 1187 1344 542 390 507

Dead stem density/ha 38 24 378 28 16 111

Shannon’s H' 4.29 3.61 3.55 4.10 3.22 3.16

Simpson’s D 0.98 0.96 0.95 0.97 0.94 0.91

Species with abun. =1 30 16 20 34 14 14

Species with abun. =2 17 8 4 18 7 10

Species with freq. =1 36 19 21 37 17 16

Species with freq. =2 14 10 9 18 10 12

Basal area (m2_{/ha) 33.9 15.3 15.4 32.0 12.2 11.2}

Arboreal foliage area (m2_{/ha) 14822 8506 10138 11850 6377 7234}

Aver. stem height (m/ind) 9.16 7.65 7.13 11.96 9.78 8.47

Max. stem height (m) - - - 32 20.9 17.6

Aver. stem incline (°/ind) 76.8 62.6 58.7 77.8 66.4 63.3

Figure 3.3.1.1: Proportion of total number of families, genera and species at the leeward, ridge and windward sites for both ≥ 5cm and ≥ 10cm diameter classes.

Figure 3.3.1.2: Proportion of species with an abundance of 1 or 2 and sub-plot frequency of 1 or 2 in each 1-ha plot at the leeward, ridge and windward sites for both ≥ 5cm and ≥ 10cm diameter classes.

The species-area curve for the leeward forest (≥ 10cm class) shows some flattening (Figure 3.3.1.3), although the 109 species recorded is much lower than the 144 and 162 predicted species of the first and second-order the Jackknife estimates respectively (32 and 48% increase). The species-area curve for the ridge forest also shows some flattening (Figure 3.3.1.4), and in a similar fashion to the leeward forest, the 51 species recorded is much lower than the 67 and 74 predicted species of the first and second-order the Jackknife estimates respectively (31 and 45% increase). The windward forest species-area curve shows a similar trend to the other forests, although the 59 species recorded was slightly closer to the 74 and 78 predicted species of the first and second-order the Jackknife estimates respectively (25 and 32% increase) compared to the other forests.

0 25 50 75 100

Lee-5cm Ridge-5cm Wind-5cm Lee-10cm Ridge-10cm Wind-10cm

% of

t

ot

al

Families Genera Species

0 25 50 75 % of Spe cie

Figure 3.3.1.3: Species-area curve for the ≥ 10cm diameter class of the leeward forest 1-ha plot.

Figure 3.3.1.4: Species-area curve for the ≥ 10cm diameter class of the ridge forest 1-ha plot.

Figure 3.3.1.5: Species-area curve for the ≥ 10cm diameter class of the windward forest 1-ha plot.

From here on in, compositional results are reported only for the ≥ 5 cm diameter class. The Melastomataceae was the dominant family (relative abundance ≥ 20%) at the leeward and ridge forests, the Clusiaceae dominated at the windward forest (relative abundance 17%), while the Cyatheaceae and the Chloranthaceae were sub-dominant (relative abundance ≥ 10%) at the leeward and ridge forests respectively (Appendix E). Other highly abundant (relative abundance ≥ 5%) families included Rubiaceae, Euphorbiaceae and Meliaceae at the leeward forest, Mysinaceae and Clusiaceae at the ridge forest, Araliaceae and Cyatheaceae at the ridge forest and Lauraceae and Cunoniaceae at all forests. The relative importance of families (IVI) largely reflected the abundance trends (Appendix F).

In terms of highly abundant genera (relative abundance ≥ 5%), Weinmannia

figured at all forests, Miconia dominated at the leeward and ridge forests,

Clusia dominated at the windward forest and also figured at the ridge forest,

Cyathea figured at the leeward and windward forests, while the leeward forest also presented Alsophila, the ridge forest Myrsine and Hedyosmum, and the ridge forest Schefflera and Freziera (Appendix E).

The leeward forest did not show any clear domination in abundance by any one species, presenting four species that can be classified as dominant (4 – 5 % relative abundance), the ridge forest was co-dominated by Miconia aprica

and Hedyosmum dombeyanum, while the windward forest dominant was

Clusia schultesii (Appendix E).

The relative importance of species (IVI) largely reflected the abundance trends, with only mostly just rearrangement of the order of the most abundant species with no significant inclusion (Appendix F).

Of the 247 species recorded, 85 % (209 spp.) were only recorded from one of the forests, 13 % (33 spp.) occurred at two forests and only 2 % (5 spp.) occurred at all three forests. The greatest overlap of species occurred between the ridge and windward forests with 25 shared species, followed by the leeward and windward forests with 13 shared species, while the leeward and ridge forests showing the least amount of overlap with only nine shared species (Appendix G).