Browsing by Autor "Isabell Hensen"

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Agroforestry species of the Bolivian Andes: an integrated assessment of ecological, economic and socio-cultural plant values
(Springer Science+Business Media, 2012) Regine Brandt; Heike Zimmermann; Isabell Hensen; Juan Carlos Mariscal Castro; Stephan Rist
Bird perches and artificial bat roosts increase seed rain and seedling establishment in tropical bracken‐dominated deforested areas
(Wiley, 2024) César Mayta; Cecilia L. López; Mariana Villegas; Luís F. Aguirre; Isabell Hensen; Silvia C. Gallegos
Tropical forests are being reduced by human activities. The use of fire for agricultural expansion generates areas dominated by the bracken fern Pteridium , where forest regeneration is slow. This may be caused by seed limitation, especially of animal‐dispersed seeds, due to the absence of seed dispersers from the forest in deforested areas, calling for restoration strategies to assist forest regeneration. We installed bird perches and artificial bat roosts to evaluate their effect on the density, species richness, and composition of animal‐dispersed seeds and seedlings of tree and non‐tree species in bracken‐dominated areas in the tropical montane forest of Bolivia. We found that perches and bat roosts increased the density and species richness of animal‐dispersed seeds and established seedlings. The seeds and seedlings dispersed by birds were clumped under the perches, while the seeds and seedlings dispersed by bats were distributed around the roosts. Perches had a higher density and species richness of seeds and seedlings compared to bat roosts, suggesting that the use of perches could be a better option as a restoration tool in bracken‐dominated areas. The increase in seed rain and seedling establishment of animal‐dispersed species in perches and bat roosts supports seed limitation, hindering forest succession in bracken‐dominated areas. The use of bird perches accompanying other restoration techniques is a promising restoration strategy to accelerate forest regeneration in tropical areas dominated by Pteridium , which are widely distributed.
Bracken fern does not diminish arbuscular mycorrhizal fungus inoculum potential in tropical deforested areas
(Springer Science+Business Media, 2021) Cecilia L. López; César Mayta; Kazuya Naoki; Jorge A. N. Quezada; Isabell Hensen; Silvia C. Gallegos
Bracken fern facilitates tree seedling recruitment in tropical fire-degraded habitats
(Elsevier BV, 2014) Silvia C. Gallegos; Isabell Hensen; Francisco Saavedra; Matthias Schleuning
Carbon dynamics in high‐<scp>A</scp>ndean tropical cushion peatlands: A review of geographic patterns and potential drivers
(Wiley, 2024) Mary Carolina García Lino; Simon Pfanzelt; Alejandra I. Domic; Isabell Hensen; Karsten Schittek; Rosa Isela Meneses; Maaike Y. Bader
Abstract Peatlands store large amounts of carbon (C), a function potentially threatened by climate change. Peatlands composed of vascular cushion plants are widespread in the northern and central high Andes (páramo, wet and dry puna), but their C dynamics are hardly known. To understand the interplay of the main drivers of peatland C dynamics and to infer geographic patterns across the Andean regions, we addressed the following question: How do topography, hydrology, temperature, past climate variability, and vegetation influence the C dynamics of these peatlands? We summarize the available information on observed spatial and inferred temporal patterns of cushion peatland development in the tropical and subtropical Andes. Based on this, we recognize the following emerging patterns, which all need testing in further studies addressing spatial and temporal patterns of C accumulation: (1) Peatlands in dry climates and those in larger catchments receive higher sediment inputs than peatlands from wet puna and páramo and in small catchments. This results in peat stratigraphies intercalated with mineral layers and affects C accumulation by triggering vegetation changes. (2) High and constant water tables favor C accumulation. Seasonal water level fluctuations are higher in wet and dry puna, in comparison with páramo, leading to more frequent episodes of C loss in puna. (3) Higher temperatures favor C gain under high and constant water availability but also increase C loss under low and fluctuating water levels. (4) C accumulation has been variable through the Holocene, but several peatlands show a recent increase in C accumulation rates. (5) Vegetation affects C dynamics through species‐specific differences in productivity and decomposition rate. Because of predicted regional differences in global climate change manifestations (seasonality, permafrost behavior, temperature, precipitation regimes), cushion peatlands from the páramo are expected to mostly continue as C sinks for now, whereas those of the dry puna are more likely to turn to C sources as a consequence of increasing aridification.
Deforested habitats lack seeds of late‐successional and large‐seeded plant species in tropical montane forests
(Wiley, 2015) Francisco Saavedra; Isabell Hensen; Matthias Schleuning
Abstract Questions (1) How do seed density and species richness of late‐successional, pioneer and non‐forest species change from forest interior to deforested habitats? (2) Are seed density and species richness of seed species dispersed into deforested areas enhanced by perch structures? (3) Do morphological seed traits of forest and non‐forest plant species change from the forest interior to deforested areas? Location Deforested tropical mountains of Chulumani, La Paz, Bolivia. Methods At eight study sites, we installed a system of 38 seed traps along a transect of 240 m from the forest interior (160 m from the forest margin) toward deforested areas (80 m from the forest margin). Half of the seed traps installed in the deforested areas were positioned under perch structures. We identified captured seeds to morpho‐species or species level and recorded morphological seed traits (i.e. seed mass, seed length, seed width) and species origin (i.e. late‐successional, pioneer, non‐forest species). Results Seed density and species richness of late‐successional and pioneer species declined from the forest interior toward deforested areas. Seed limitation was particularly strong for large‐seeded species. Perches in deforested areas strongly increased the density and to some extent as well as the species richness of seeds dispersed into these areas, but did not alter the composition of seed traits and species origin in comparison to seed traps without perches. Conclusions We found a strong seed dispersal limitation in deforested areas, which was mitigated by the presence of perch structures, at least in terms of seed density and species richness. However, the dispersal limitation of late‐successional plant species with large seeds was not compensated by the presence of perching structures. Nevertheless, the establishment of artificial perch structures is likely to be a promising strategy for capturing seeds in deforested areas that may establish under bracken fronds in the long term.
Differences in bird and bat traits, seed-dispersal interactions and functions between tropical montane forest and bracken-dominated areas
(Frontiers Media, 2025) César Mayta; Matthias Schleuning; Cecilia L. López; Mariana Villegas; Isabell Hensen; Silvia C. Gallegos
Most tropical plant species depend on animals to disperse their seeds. Seed dispersal by animals allows plants to colonize new sites in deforested habitats helping to accelerate forest recovery. However, deforestation can affect the interactions between animals and plants that are crucial for forest regeneration. In this study, we analyze the differences on the composition of functional traits and on seed-dispersal interactions and functions by birds and bats between forest and deforested areas dominated by bracken fern. At eight study sites, we captured birds and bats in bracken-dominated areas and at forest in the tropical montane forest of Bolivia and analyzed their droppings. We found a similar composition of functional traits related to animal size, gape width and degree of frugivory of bats in both habitat types. Hand-wing index of birds was significantly higher in bracken compared to forest. Birds had more interaction richness and abundance in bracken than in forest, and bats had more interaction abundance in forest than in bracken. The majority of seeds dispersed by birds and bats in bracken were from pioneer species. We conclude that, although seed dispersal by birds and bats is maintained in the bracken-dominated areas, most of the dispersed seeds belong to pioneer species. Pioneer species are unlikely to establish in bracken-dominated areas, making the natural regeneration process of these deforested areas very slow.
Disentangling the roles of bracken fronds and litter on natural seedling recruitment in fire-disturbed tropical montane habitats
(Elsevier BV, 2024) Cecilia L. López; César Mayta; A C.; Mariana Villegas; Emili Antonia Jiménez; Víctor Vásquez; Isabell Hensen; Silvia C. Gallegos
Tropical montane forests are diverse ecosystems often affected by uncontrolled human-induced fires causing tree mortality and creating large deforested areas. After fires, Pteridium spp. ferns (bracken) often dominate, and forest regeneration in these areas is slow. In this study, we evaluated the effects of bracken fronds and litter, as well as the micro-environmental conditions created by the fern, on the density and species diversity of naturally recruiting seedlings. At eight sites, 120 experimental plots were established among forest and bracken-dominated areas with the following treatments: (a) fronds and litter intact (F+L+); (b) fronds intact and litter removed (F+L-); (c) fronds removed and litter intact (F-L+); and (d) fronds and litter removed (F-L-). After one year, all seedlings were registered, identified and classified according to their life-form (tree, shrub, herb, vine), dispersal vector (wind- or animal-dispersed) and successional status (early-, mid-, and late-successional). For all treatments we assessed 12 micro-environmental variables. We identified 3649 naturally-recruiting seedlings corresponding to 278 species from 70 families. We found positive effects of bracken fronds particularly on tree seedling recruitment: treatments with fronds had greater densities of both animal- and wind-dispersed tree seedlings, 1.8 and 1.4 fold higher, respectively, compared to treatments without fronds. Similarly, the density of early-, mid- and late-successional tree species was 1.3, 1.7 and 1.9 times higher in treatments with than without fronds. Furthermore, species diversity of early-, mid- and late-successional tree species was higher in the treatments with fronds. The environmental conditions generated by bracken presence, such as photosynthetically active radiation, soil temperature, live bracken biomass and litter depth, had positive effects on seedling density of all, animal-dispersed and early-successional tree species, and negative effects on seedling recruitment of other life-forms, notably from early successional stages. To promote forest regeneration in bracken-dominated areas, active restoration measures such as direct seed addition and transplants of nursery-raised seedlings of mid- and late-successional species should be considered. Since bracken can hinder the establishment of some life forms and species but favor others, it is recommended to include a trait-based approach to understand species responses to environmental factors and select species that are optimally adapted to bracken-dominated habitat conditions to promote forest regeneration. • Bracken facilitates seedling recruitment of mid- and late-successional tree species. • Bracken fronds’ shade increases species diversity of tree seedlings. • Bracken litter decreases natural recruitment of herbs. • Animal-dispersed species have higher recruitment under bracken fronds and litter.
Effects of disturbance and altitude on soil seed banks of tropical montane forests
(Cambridge University Press, 2013) Denis Lippok; Florian Walter; Isabell Hensen; Stephan Beck; Matthias Schleuning
Abstract: Vast areas of tropical forests have been deforested by human activities, resulting in landscapes comprising forest fragments in matrices of deforested habitats. Soil seed banks (SSB) are essential sources for the regeneration of tropical forests after disturbance. In a fragmented montane landscape in the Bolivian Andes, we investigated SSB in three different habitat types that were associated with different degrees of disturbance, i.e. in forest interior, at forest edges and in deforested habitats. Sampling of habitats was replicated at six sites ranging in altitude from 1950 to 2450 m asl. We extracted seeds from dried soil samples by sieving, classified seeds into morphospecies and size classes, and characterized SSB in terms of density, species richness and composition. We tested effects of disturbance (i.e. habitat type) and altitude on SSB characteristics. Overall, small seeds (<1 mm) dominated SSB (81% of sampled seeds). Seed density and species richness were lowest in deforested habitats, especially in large seeds and distant from adjacent forests (≥20 m), while small-seeded species were most numerous near forest margins. Species turnover between habitats was high. Altitude altered the composition of SSB, but had no effects on seed density and species richness. We conclude that the potential of SSB for natural regeneration of deforested habitats is low and decreases with increasing distance from forest remnants and that forest edges may be eventually invaded by small-seeded species from deforested habitats.
Elevation, Topography, and Edge Effects Drive Functional Composition of Woody Plant Species in Tropical Montane Forests
(Wiley, 2015) Amira Apaza‐Quevedo; Denis Lippok; Isabell Hensen; Matthias Schleuning; Sabine Both
Abstract Tropical montane forests comprise heterogeneous environments along natural gradients of topography and elevation. Human‐induced edge effects further increase the environmental heterogeneity in these forests. The simultaneous effects of natural and human‐induced gradients on the functional diversity of plant leaf traits are poorly understood. In a tropical montane forest in Bolivia, we studied environmental gradients associated with elevation (from 1900 m to 2500 m asl), topography (ridge and gorge), and edge effects (forest edge vs. forest interior), and their relationship with leaf traits and resource‐use strategies. First, we investigated associations of environmental conditions (soil properties and microclimate) with six leaf traits, measured on 119 woody plant species. Second, we evaluated changes in functional composition with community‐weighted means and functional structure with multidimensional functional diversity indices ( FR ic, FE ve and FD iv). We found significant associations between leaf traits and soil properties in accordance with the trade‐off between acquisition and conservation of resources. Functional composition of leaf traits shifted from the dominance of acquisitive species in habitats at low altitudes, gorges, and forest interior to the dominance of conservative species in habitats at high altitudes, ridges, and forest edges. Functional structure was only weakly associated with the environmental gradients. Natural and human‐induced environmental gradients, especially soil properties, are important for driving leaf traits and resource‐use strategies of woody plants. Nevertheless, weak associations between functional structure and environmental gradients suggest a high redundancy of functional leaf traits in this tropical montane forest.
Facilitative and competitive effects of bracken fronds and litter on tree seedling recruitment
(Frontiers Media, 2025) Cecilia L. López; César Mayta; Andrea Soliz; Isabell Hensen; Silvia C. Gallegos
Introduction Tropical montane forests are diverse ecosystems increasingly threatened by land-use change and frequent uncontrolled fires caused by humans. After these fires, affected areas are often dominated by ferns of the genus Pteridium (bracken), delaying the rate of forest regeneration. This study examined the facilitative and competitive roles of bracken fronds and litter on seedling establishment, recruitment success, and growth after 36 months, and the extent to which these effects depend on seed size in early plant development processes. Methods At eight sites, we conducted seed addition and seedling-transplant experiments in plots established in bracken-dominated areas, using the following treatments: (a) fronds and litter intact (F+L+); (b) fronds intact and litter removed (F+L−); (c) fronds removed and litter intact (F−L+); and (d) fronds and litter removed (F−L−). Results A total of 46,640 seeds from 24 tree species were sown and 1,070 nursery-raised seedlings transplanted. In treatments with fronds and litter, seedling establishment and recruitment success increased with seed size. In contrast, in the treatment without fronds and litter all the species had low performance. Fronds proved to be highly beneficial for all seed sizes and for all early development processes. Litter, on the other hand, had negative effects on small-seeded species during establishment, but had neutral to positive effects on the recruitment and growth of all species. Discussion The disadvantage of small seeds under bracken litter may be related to the high light requirements of seedlings, as litter accumulation reduces light transmission. Species with large seeds and shade tolerance benefit from bracken frond cover, suggesting that restoration strategies in bracken-dominated areas should prioritize these species. Moreover, planting seeds or seedlings shortly after fire, in the presence of bracken fronds and before litter accumulation would be most beneficial for tree species. Additionally, seed dispersers play a crucial role in transporting large seeds into bracken-dominated areas, emphasizing the need for an integrated approach that considers biotic and abiotic factors for effective forest recovery.
Factors limiting montane forest regeneration in bracken-dominated habitats in the tropics
(Elsevier BV, 2016) Silvia C. Gallegos; Stephan Beck; Isabell Hensen; Francisco Saavedra; Denis Lippok; Matthias Schleuning
Forest fragmentation and edge effects on the genetic structure of<i>Clusia sphaerocarpa</i>and<i>C. lechleri</i>(Clusiaceae) in tropical montane forests
(Cambridge University Press, 2013) Amira Apaza‐Quevedo; Matthias Schleuning; Isabell Hensen; Fransisco Saavedra; Walter Durka
Abstract: Fragmentation of tropical forests influences abiotic and biotic processes that affect the genetic structure of plant populations. In forest fragments, edge effects, i.e. changes of abiotic and biotic factors at forest edges, may be prevalent. In two forest fragments ( c . 200 ha at c . 2450 m asl) of tropical montane forest in Bolivia, sympatric populations of the dioecious tree species Clusia sphaerocarpa and C. lechleri were used as case study species to compare genetic diversity and small-scale genetic structure (SGS) between edge and interior habitats. Eight microsatellite markers were employed to genotype 343 individuals including adults, juveniles and seedlings of C. sphaerocarpa and 196 of C. lechleri . Genetic differentiation was found between habitats in both species (Φ RT = 0.071 for C. sphaerocarpa and Φ RT = 0.028 for C. lechleri ) and among ages in C. sphaerocarpa (Φ RT = 0.016). Overall, SGS was weak but significant with more pronounced SGS in C. lechleri ( Sp = 0.0128) than in C. sphaerocarpa ( Sp = 0.0073). However, positive spatial genetic autocorrelation extended only up to 10 m. For C. sphaerocarpa , SGS was stronger in seedling and juvenile stages than in adults and in the forest interior than at forest edges. Our results show that edge effects can extend to the genetic level by breaking-up local genetic structures, probably due to increased gene flow and enhanced pollination and seed-dispersal interactions at forest edges.
Forest recovery of areas deforested by fire increases with elevation in the tropical Andes
(Elsevier BV, 2013) Denis Lippok; Stephan Beck; Daniel Renison; Silvia C. Gallegos; Francisco Saavedra; Isabell Hensen; Matthias Schleuning
Functional importance of avian seed dispersers changes in response to human-induced forest edges in tropical seed-dispersal networks
(Springer Science+Business Media, 2014) Francisco Saavedra; Isabell Hensen; Stephan Beck; Katrin Böhning‐Gaese; Denis Lippok; Till Töpfer; Matthias Schleuning
Human-Induced Disturbance Alters Pollinator Communities in Tropical Mountain Forests
(Multidisciplinary Digital Publishing Institute, 2012) Stephan Kambach; Fernando Guerra; Stephan Beck; Isabell Hensen; Matthias Schleuning
Mountain forest ecosystems in the Andes are threatened by deforestation. Increasing fire frequencies lead to fire-degraded habitats that are often characterized by a persistent fern-dominated vegetation. Little is known about the consequences of these drastic changes in habitat conditions for pollinator communities. In a rapid diversity assessment, we collected individuals of two major groups of insect pollinators (bees and butterflies/moths) with pan traps and compared pollinator diversities in a spatial block design between forest interior, forest edge and adjacent fire-degraded habitats at eight sites in the Bolivian Andes. We found that bee species richness and abundance were significantly higher in fire-degraded habitats than in forest habitats, whereas species richness and abundance of butterflies/moths increased towards the forests interior. Species turnover between forest and fire-degraded habitats was very high for both pollinator groups and was reflected by an increase in the body size of bee species and a decrease in the body size of butterfly/moth species in fire-degraded habitats. We conclude that deforestation by frequent fires has profound impacts on the diversity and composition of pollinator communities. Our tentative findings suggest shifts towards bee-dominated pollinator communities in fire-degraded habitats that may have important feedbacks on the regenerating communities of insect-pollinated plant species.
Influence of Bracken Fronds and Leaf Litter Management on Soil Seed Bank Characteristics in a Fire‐Disturbed Tropical Montane Forest
(Wiley, 2025) Emili Antonia Jiménez; Cecilia L. López; Alfredo F. Fuentes; Isabell Hensen; Silvia C. Gallegos
ABSTRACT The bracken fern Pteridium spp. dominates postfire vegetation in tropical montane forests, where fronds, litter, allelopathy, and dispersal limitation hinder forest regeneration. However, this species' effect on soil seed bank remains poorly understood. We investigated the effects of bracken fronds and litter on the abundance, richness, and species diversity of the soil seed bank in a tropical montane fire‐deforested area in Bolivia. At eight study sites (1800–2350 a.s.l), soil samples were collected under five treatments: (a) fronds and litter intact (F + L+), (b) fronds intact and litter removed (F + L−), (c) fronds removed and litter intact (F−L+), (d) fronds and litter removed (F−L−), and (e) forest. Using the seedling emergence method, samples were assessed every 20 days over 8 months (September 2021–May 2022). Compared to intact bracken, forest areas showed 2.6, 1.7, and 1.5‐fold greater abundance, species richness, and diversity of zoochorous species, respectively. Among bracken treatments, abundance, richness, and diversity of zoochorous species decreased by 2.7, 2.6, and 2 times, respectively, when fronds and litter were removed, compared to the intact bracken treatment, but were not significantly different when only litter was removed. Our findings indicate that in bracken‐dominated environments, fronds and litter improve microclimatic conditions, maintaining the viability of zoochorous species in the soil seed bank. The removal of litter without cutting fronds reduces light interception and seed trapping while maintaining zoochorous seed germination capacity in the soil, and might be a better management strategy than removing fronds and litter to promote seedling recruitment from the soil seed bank.
Morphological trait matching shapes plant–frugivore networks across the Andes
(Wiley, 2018) Irene M. A. Bender; W. Daniel Kissling; Pedro G. Blendinger; Katrin Böhning‐Gaese; Isabell Hensen; Ingolf Kühn; Marcia C. Muñoz; Eike Lena Neuschulz; Larissa Nowak; Marta Quitián
Interactions between resource and consumer species are organized in ecological networks. Species interactions in these networks are influenced by the functional traits of the interacting partners, but the generality of trait‐based interaction rules and the relationship between functional traits and a species’ specialization on specific interaction partners are not yet understood. Here we combine data on eight interaction networks between fleshy‐fruited plants and frugivorous birds sampled across the tropical and subtropical Andean range. We test which combinations of morphological plant and animal traits determine trait matching between resource and consumer species in these networks. In addition, we test which of the morphological traits influence functional specialization of plant and bird species. In a meta‐analysis across network‐specific fourth‐corner analyses, we found that plant–animal trait pairs related to size matching (fruit size–beak size) and avian foraging behavior (plant height–wing shape and crop mass–body mass) were positively related in these networks. The degree of functional specialization on specific interaction partners was positively related to crop mass in plants and to the pointedness of the wing in birds. Our findings show that morphological trait matching between fleshy‐fruited plants and frugivorous birds is a general phenomenon in plant–frugivore networks across the Andes and that specific plant and bird traits can be used to approximate the degree of functional specialization. These insights into the generality of interaction rules are the base for predictions of species interactions in ecological networks, for instance in novel communities in the future, and can be applied to identify plant and animal species that fulfill specialized functional roles in ecological communities.
Non-woody life-form contribution to vascular plant species richness in a tropical American forest
(2008) Reynaldo Linares‐Palomino; Víctor Manuel Pardo Cardona; Ernest I. Hennig; Isabell Hensen; Doreen Hoffmann; Jasmin Lendzion; Daniel P. Soto; Sebastián K. Herzog; Michael Kessler
We provide total vascular plant species counts for three 1-ha plots in deciduous, semi-deciduous and evergreen forests in central Bolivia. Species richness ranged from 297 species and 22,360 individuals/ha in the dry deciduous forest to 382 species and 31,670 individuals/ha in the evergreen forest. Orchidaceae, Pteridophyta and Leguminosae were among the most species-rich major plant groups in each plot, and Peperomia (Piperaceae), Pleurothallis (Orchidaceae) and Tillandsia (Bromeliaceae), all epiphytes, were the most species-rich genera. This dominance of a few but very diverse and/or widespread taxa contrasted with the low compositional similarity between plots. In a neotropical context, these Central Bolivian forest plots are similar in total species richness to other dry deciduous and humid montane forests, but less rich than most Amazonian forests. Nevertheless, lianas, terrestrial herbs and especially epiphytes proved to be of equal or higher species richness than most other neotropical forest inventories from which data are available. We therefore highlight the importance of non-woody life-forms (especially epiphytes and terrestrial herbs) in Andean foothill forest ecosystems in terms of species richness and numbers of individuals, representing in some cases nearly 50% of the species and more than 75% of the individuals. These figures stress the need for an increased inventory effort on non-woody plant groups in order to accurately direct conservation actions.
Non-woody life-form contribution to vascular plant species richness in a tropical American forest
(Springer Science+Business Media, 2008) Reynaldo Linares‐Palomino; Víctor Manuel Pardo Cardona; Ernest I. Hennig; Isabell Hensen; Doreen Hoffmann; Jasmin Lendzion; Daniel P. Soto; Sebastián K. Herzog; Michael Kessler
We provide total vascular plant species counts for three 1-ha plots in deciduous, semi-deciduous and evergreen forests in central Bolivia. Species richness ranged from 297 species and 22,360 individuals/ha in the dry deciduous forest to 382 species and 31,670 individuals/ha in the evergreen forest. Orchidaceae, Pteridophyta and Leguminosae were among the most species-rich major plant groups in each plot, and Peperomia (Piperaceae), Pleurothallis (Orchidaceae) and Tillandsia (Bromeliaceae), all epiphytes, were the most species-rich genera. This dominance of a few but very diverse and/or widespread taxa contrasted with the low compositional similarity between plots. In a neotropical context, these Central Bolivian forest plots are similar in total species richness to other dry deciduous and humid montane forests, but less rich than most Amazonian forests. Nevertheless, lianas, terrestrial herbs and especially epiphytes proved to be of equal or higher species richness than most other neotropical forest inventories from which data are available. We therefore highlight the importance of non-woody life-forms (especially epiphytes and terrestrial herbs) in Andean foothill forest ecosystems in terms of species richness and numbers of individuals, representing in some cases nearly 50% of the species and more than 75% of the individuals. These figures stress the need for an increased inventory effort on non-woody plant groups in order to accurately direct conservation actions.