Human impact diminishes seedling species richness in Kakamega Forest, Kenya

Farwig, Nina; Sajita, Nixon; Schaab, Gertrud; Böhning‐Gaese, Katrin

doi:10.1016/j.baae.2007.05.006

Cited by 16 publications

(33 citation statements)

References 39 publications

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“…The lower richness found could be the result of species local extinction, due to the legacy effects of historical over-extraction which led to the long-term reduction of diversity (Farwig et al 2008). In this study, the greatest diversity of adult trees was recorded in the forest with the highest intensity of extraction (H1); however, this stems from the lower dominance of shadetolerant species and the greater contribution of pioneer species.…”

Section: Effects Of Selective Logging On Cloud Forest Structure and Dcontrasting

confidence: 38%

“…In a recent metaanalysis of tropical forests, Martin et al (2015) found that tree richness increased with low logging intensities and vice versa. Most studies agree that selective logging has a significant influence on species composition (Decocq et al 2014, Farwig et al 2008, while other studies report effects on functional guilds or ecological groups (Carreño-Rocabado et al 2012, Imai et al 2012.…”

Section: Introductionmentioning

confidence: 92%

“…Studies of the effect of selective logging on the diversity of tree regeneration in tropical forests under planned forestry management have produced contrasting results. While selective logging can negatively affect the diversity and regeneration of tropical and temperate forests (Farwig et al 2008, Clark & Covey 2012, opening of the canopy as a consequence of planned extraction can also have positive effects on the regeneration of certain timber species (Guariguata & Sáenz 2002, Götmark 2007, Duah-Gyamfi et al 2014. In a recent metaanalysis of tropical forests, Martin et al (2015) found that tree richness increased with low logging intensities and vice versa.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Can traditional selective logging secure tree regeneration in cloud forest?

Ortiz-Colín¹,

Toledo‐Aceves²,

López‐Barrera³

et al. 2017

iForest

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(2) Unplanned selective logging for charcoal and firewood is a common practice in tropical montane cloud forest (TMCF), a high priority ecosystem for biodiversity conservation at the global scale. However, limited information is available regarding the impact of such logging on forest regeneration. We evaluated the abundance and composition of tree regeneration in four TMCF sites subject to traditional selective logging in southern Mexico. ). In all sites, species of intermediate shade-tolerance dominated the regeneration (76%), followed by the shadetolerant (23%) and pioneer (1%) species. Regeneration of Quercus spp. (four species) dominated at all sites (50.5%); this is a group of particular interest to the local communities because of its utility for firewood and charcoal. The similarity in composition between adult and regenerating tree species was relatively high in all of the sites (Morisita-Horn Index L1=0.86, L2=0.64, H1=0.69 and H2=0.71). These results indicate that, under the evaluated selective logging intensities, TMCF can sustain sufficient regeneration of Quercus spp. and thus presents an opportunity for sustainable management. The legacy effects of traditional selective logging on TMCF tree regeneration are discussed.

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Section: Effects Of Selective Logging On Cloud Forest Structure and Dcontrasting

confidence: 38%

Section: Introductionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Can traditional selective logging secure tree regeneration in cloud forest?

Ortiz-Colín¹,

Toledo‐Aceves²,

López‐Barrera³

et al. 2017

iForest

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“…This species requires permanent soil moisture and abundant organic matter to regenerate (Donoso et al 2007 and references therein). As pointed out by other studies (Farwig et al 2008), disturbed habitat conditions might likewise influence the establishment of late successional species such as S. conspicua, P. nubigena or L. philippiana. In contrast, A. luma, a forest species with wider tolerance to several altered conditions, showed a positive response to humaninduced disturbances, due mostly to its capacity to reproduce asexually (Donoso and Escobar 2006); this might be one of the reasons why A. luma is one of the most common species in temperate evergreen forests of the region (Veblen et al 1981).…”

Section: Effects Of Cattle and Selective Logging On Regeneration Commmentioning

confidence: 98%

“…These results confirmed that cattle grazing can diminish, damage or prevent the recruitment of tree species by browsing and trampling, which can in turn induce changes in species composition (Hobbs 2001, Baraloto et al 2012, ZamoranoElgueta et al 2012. Selective logging, on the other hand, can cause negative impacts on seedling richness (Farwig et al 2008), tree species diversity (Polyakov et al 2007, Ramírez-Marcial et al 2001, and functional composition of forest communities (Baraloto et al 2012). …”

Section: Effects Of Cattle and Selective Logging On Regeneration Commmentioning

confidence: 99%

The differential influences of human‐induced disturbances on tree regeneration community: a landscape approach

et al. 2014

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Abstract. Understanding the processes shaping biological communities under interacting disturbances is a core challenge in ecology. Although the impacts of human-induced disturbances on forest ecosystems have been extensively studied, less attention has been paid to understanding how tree regeneration at the community level responds to such disturbances. Moreover, these previous studies have not considered how these effects change according to major social and environmental factors that can influence forest use at a landscape scale. In this study, we investigate the effects of cattle grazing and selective logging on the composition of tree regeneration communities in relation to forest successional stage and land tenure regime in Chilean temperate forests, a global biodiversity hotspot. We recorded seedlings, saplings and basal area of stumps of tree species (as a surrogate for selective logging), and number of cattle dung pats (as a surrogate for cattle pressure) in 129 25 3 20 m plots in small (,200 ha) and large properties in different successional stages (old-growth, intermediate, secondary forests). The regeneration of the ten more abundant species as predicted by human disturbance, land tenure, forest successional stage, and number of parent trees was modelled using generalised linear models. Predictions for each individual model were made under different scenarios of human disturbance. The predicted regeneration results were assembled and subjected to ordination analyses and permutation multivariate analyses of variance to determine differences in regeneration composition under each scenario. In most cases, best-fit models contained at least one of the explanatory variables accounting for human disturbance. The effects of selective logging on tree regeneration varied depending on land tenure regime, but cattle grazing always exhibited a negative effect. Our results revealed that cattle have a more negative effect on forest regeneration than selective logging, especially in old-growth forests and small properties. Our analytical approach contributes to the understanding of the differential influence of human-induced disturbances on the tree regeneration community at a landscape scale. It can inform conservation policies and actions, which should focus on addressing the main disturbance factors and on developing strategies to conserve the most sensitive species to such disturbances.

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Regeneration potential in South African forest fragments: extinction debt paid off or hampered by contemporary matrix modification?

2015

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Deforestation generates forest fragments within modified matrices with frequently detrimental outcomes for species persistence. In historically fragmented forests, however, species have evolved under fragmented conditions and might be more resistant to matrix modification. We examined the effect of contemporary matrix modification on forest regeneration potential in historically fragmented scarp-forest fragments in KwaZulu-Natal, South Africa. We compared tree, seedling and sapling richness, abundance and composition in four forest-fragment types varying in size and matrix modification: large and small forest fragments surrounded by indigenous grassland and small forest fragments enclosed by eucalypt and sugarcane plantations. Additionally, seedlings and saplings were classified according to their origin as local/immigrant to assess matrix permeability for seed dispersers. Trees and saplings were slightly, and seedlings were strongly affected by matrix modification: seedling richness and abundance were significantly lower in fragments with sugarcane compared to fragments with grassland matrix. Furthermore, all stage classes revealed compositional differences with more light-tolerant species occurring in fragments with modified matrices. We suggest that human activities associated with matrix modification have altered abiotic factors favouring light-tolerant species. Changes in biotic interactions seemed to be less important as immigrant recruitment occurred in all fragments implying matrix permeability. Our findings demonstrate that contemporary matrix modification might threaten forest regeneration potential in historical scarp-forest fragments. Reduced seedling recruitment might indicate a time lag in local species extinction, as trees regenerate slowly. We recommend using both recruitment stages as early warning indicators. Further, including small scarp-forest fragments into protected area networks will minimise human impact associated with matrix modification.

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Human impact diminishes seedling species richness in Kakamega Forest, Kenya

Cited by 16 publications

References 39 publications

Can traditional selective logging secure tree regeneration in cloud forest?

Can traditional selective logging secure tree regeneration in cloud forest?

The differential influences of human‐induced disturbances on tree regeneration community: a landscape approach

Regeneration potential in South African forest fragments: extinction debt paid off or hampered by contemporary matrix modification?

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