Tropical landscapes are dominated by land‐use systems, but their contribution to the conservation of biodiversity is largely unknown. Since changes in biodiversity in response to human impact are known to differ widely among taxonomic groups and guilds, there is a need for multidisciplinary collaboration of plant, vertebrate, and invertebrate experts. We used inventories of trees, understory plants, birds (subdivided into endemics, insectivores, frugivores/nectar feeders), butterflies (endemics, fruit feeders), and dung beetles in Sulawesi (Indonesia) to characterize a gradient from near‐primary to secondary forests, agroforestry systems, and annual crops. As expected, overall species richness tended to decrease within this gradient of increasing habitat modification, but, in contrast to previous studies, we found the species richness between most taxonomic groups to be significantly correlated (36 out of 38 pairwise comparisons). However, on average only 48% of the variance could be explained (within the five main groups), and only a few taxonomic groups/guilds turned out to be good predictors for others: for example, trees for fruit‐ and nectar‐feeding birds (88% explanation) and fruit‐feeding butterflies (83%), endemic birds for endemic butterflies (72%), and frugivorous/nectar‐feeding birds for fruit‐feeding butterflies (67%). Although biodiversity of land‐use systems showed taxonomic group‐ and guild‐specific differences, most groups were affected in a similar way by habitat modification. Near‐primary forest sites proved to be of principal importance for conservation; however, land‐use systems such as secondary forests (for understory plants, birds, and butterflies) and agroforestry systems (for butterflies) supported relatively high numbers of species and might play a significant role for biodiversity conservation in tropical landscapes.

Aim To document the elevational pattern of epiphyte species richness at the local scale in the tropical Andes with a consistent methodology.Location The northern Bolivian Andes at 350-4000 m above sea level.Methods We surveyed epiphytic vascular plant assemblages in humid forests in (a) single trees located in (b) 90 subplots of 400 m 2 each located in (c) 14 plots of 1 ha each. The plots were separated by 100-800 m along the elevational gradient. ResultsWe recorded about 800 epiphyte species in total, with up to 83 species found on a single tree. Species richness peaked at c. 1500 m and declined by c. 65% to 350 m and by c. 99% to 4000 m, while forests on mountain ridges had richness values lowered by c. 30% relative to slope forests at the same elevations. The hump-shaped richness pattern differed from a nullmodel of random species distribution within a bounded domain (the middomain effect) as well as from the pattern of mean annual precipitation by a shift of the diversity peak to lower elevations and by a more pronounced decline of species richness at higher elevations. With the exception of Araceae, which declined almost monotonically, all epiphyte taxa showed hump-shaped curves, albeit with slightly differing shapes. Orchids and pteridophytes were the most species-rich epiphytic taxa, but their relative contributions shifted with elevation from a predominance of orchids at low elevations to purely ferndominated epiphyte assemblages at 4000 m. Within the pteridophytes, the polygrammoid clade was conspicuously overrepresented in dry or cold environments. Orchids, various small groups (Cyclanthaceae, Ericaceae, Melastomataceae, etc.), and Bromeliaceae (below 1000 m) were mostly restricted to the forest canopy, while Araceae and Pteridophyta were well represented in the forest understorey.Main conclusions Our study confirms the hump-shaped elevational pattern of vascular epiphyte richness, but the causes of this are still poorly understood. We hypothesize that the decline of richness at high elevations is a result of low temperatures, but the mechanism involved is unknown. The taxon-specific patterns suggest that some taxa have a phylogenetically determined propensity for survival under extreme conditions (low temperatures, low humidity, and low light levels in the forest interior). The three spatial sampling scales show some different patterns, highlighting the influence of the sampling methodology.

We studied species richness, composition, and vertical distribution of vascular epiphytes at two sites in the Bolivian Andes. To account for the epiphyte flora on understory trees, epiphytes on shrubs and small trees were sampled in 20 · 20 m 2 subplots around each sampled canopy tree; this understory zone U is introduced as an addition to the well-established five vertical Johansson tree zones. More than 20% of about 500 species recorded were found only in the understory subplots, including ca. 40% of aroids, 35%-40% of piperoids, and 25%-30% of ferns. Habitat generalists (occurring in three or more zones) were most common, contributing about 50% of all species, specialists (occurring only in two zones, or in three continuous ones) 34%-42%, and hemiepiphytes 6%-16%. Canopy epiphytes (occurring > 90% in tree zones Z3-5) were mainly represented by orchids and ferns, many with special adaptations to drought stress such as pseudobulbs, succulence, and poikilohydry. Trunk epiphytes ( > 90% in understory and tree zones Z1-2) reached highest relative species numbers among piperoids and ferns. Most hemiepiphytes were also trunk epiphytes, due to their characteristic growth pattern, and included mainly aroids. The vertical distribution of epiphytes within a tree is determined by several microenvironmental gradients, with light intensity, wind speed, and air temperature increasing and air humidity decreasing from the ground level to the canopy.

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Species richness, community composition and ecology of cryptogamic epiphytes (bryophytes, macrolichens) were studied in upper montane primary, early secondary and late secondary oak forests of the Cordillera de Talamanca, Costa Rica. Canopy trees of Quercus copeyensis were sampled with the aim of getting insight in patterns and processes of epiphyte succession and recovery of diversity in secondary forest following forest clearing. Species richness of cryptogamic epiphytes in secondary and primary forests were nearly the same, showing that primary forests are not necessarily more diverse than secondary forests. High species richness of secondary forests was presumed due to the closed canopy, resulting in permanently high atmospheric humidity in these forests. Similarity in species composition of secondary and primary forests increases with forest age, but after 40 years of succession one third (46 species) of primary forest species had not re-established in the secondary forest. Community composition in primary and secondary forests differed markedly and indicates that a long time is needed for the re-establishment of microhabitats and reinvasion of species and communities adapted to differentiated niches. Genera and species exclusive to primary forests are relevant as indicator taxa and conservation targets. Forty percent (68 species) of all species recorded are restricted to secondary forests, indicating the important contribution of secondary forest diversity to total species richness of the oak forests of Costa Rica.