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Aim: Andean montane forests are biodiversity hotspots and large carbon stores and they provide numerous ecosystem services. Following land abandonment after centuries of forest clearing for agriculture in the Andes, there is an opportunity for forest recovery. Field‐based studies show that forests do not always recover. However, large‐scale and long‐term knowledge of recovery dynamics of Andean forests remains scarce. This paper analyses tropical montane forest recovery trajectories over a 15‐year time frame at the landscape and tropical Andean scale to inform restoration planning. Methods: We first detect "potential recovery" as areas that have experienced a forest transition between 2000 and 2005. Then, we use Landsat time series analysis of the normalized difference water index (NDWI) to classify four "realized recovery" trajectories ("ongoing", "arrested", "disrupted" and "no recovery") based on a sequential pattern of 5‐yearly Z‐score anomalies for 2005–2020. We compare these results against an analysis of change in tree cover to validate against other datasets. Results: Across the tropical Andes, we detected a potential recovery area of 274 km2 over the period. Despite increases in tree cover, most areas of the Andes remained in early successional states (10–25% tree cover), and NDWI levelled out after 5–10 years. Of all potential forest recovery areas, 22% showed "ongoing recovery", 61% showed either "disrupted" or "arrested recovery", and 17% showed "no recovery". Our method captured forest recovery dynamics in a Peruvian arrested succession context and in landscape‐scale tree‐planting efforts in Ecuador. Main conclusions: Forest recovery across the Andes is mostly disrupted, arrested or unsuccessful, with consequences for biodiversity recovery and provision of ecosystem services. Low‐recovery areas identified in this study might be good candidates for active restoration interventions in this UN Decade on Restoration. Future studies could determine restoration strategies and priorities and suggest management strategies at a local planning scale across key regions in the biodiversity hotspot. [ABSTRACT FROM AUTHOR]

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Regrowing secondary forests dominate tropical regions today, and a mechanistic understanding of their recovery dynamics provides important insights for conservation. In particular, land‐use legacy effects on the fauna have rarely been investigated. One of the most ecologically dominant and functionally important animal groups in tropical forests are the ants. Here, we investigated the recovery of ant communities in a forest–agricultural habitat mosaic in the Ecuadorian Chocó region. We used a replicated chronosequence of previously used cacao plantations and pastures with 1–34 years of regeneration time to study the recovery dynamics of species communities and functional diversity across the two land‐use legacies. We compared two independent components of responses on these community properties: resistance, which is measured as the proportion of an initial property that remains following the disturbance; and resilience, which is the rate of recovery relative to its loss. We found that compositional and trait structure similarity to old‐growth forest communities increased with regeneration age, whereas ant species richness remained always at a high level along the chronosequence. Land‐use legacies influenced species composition, with former cacao plantations showing higher resemblance to old‐growth forests than former pastures along the chronosequence. While resistance was low for species composition and high for species richness and traits, all community properties had similarly high resilience. In essence, our results show that ant communities of the Chocó recovery rapidly, with former cacao reaching predicted old‐growth forest community levels after 21 years and pastures after 29 years. Recovery in this community was faster than reported from other ecosystems and was likely facilitated by the low‐intensity farming in agricultural sites and their proximity to old‐growth forest remnants. Our study indicates the great recovery potential for this otherwise highly threatened biodiversity hotspot. [ABSTRACT FROM AUTHOR]

Much has yet to be learned of the spatial patterning of pre-Columbian people across the Tropical Andes. Using compiled archaeological data and a suite of environmental variables, we generate an ensemble species distribution model (SDM) that incorporates general additive models, random forest models and Maxent models to reconstruct spatial patterns of pre-Columbian people that inhabited the Tropical Andes east of the continental divide, within the modern countries of Bolivia, Peru and Ecuador. Within this region, here referred to as the eastern Andean flank, elevation, mean annual cloud frequency, distance to rivers and precipitation of the driest quarter are the environmental variables most closely related to human occupancy. Our model indicates that 11.04% of our study area (65 368 km2) was likely occupied by pre-Columbian people. Our model shows that 30 of 351 forest inventory plots, which are used to generate ecological understanding of Andean ecosystems, were likely occupied in the pre-Columbian period. In previously occupied sites, successional trajectories may still be shaping forest dynamics, and those forests may still be recovering from the ecological legacy of pre-Columbian impacts. Our ensemble SDM links palaeo- and neo-ecology and can also be used to guide both future archaeological and ecological studies. This article is part of the theme issue 'Tropical forests in the deep human past'. [ABSTRACT FROM AUTHOR]

Copyright of Biotropica is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Information about nutrient dynamics is of upmost importance in order to contribute to the restoration of degraded forest environments in the Andes of southern Ecuador. This study aims to investigate the differences of nutrient dynamics between a native alder (Alnus acuminata) and an exotic pine (Pinus patula) tree species in this region. Based on litterfall, forest floor and mineral topsoil (0–20 cm) of two pine and two alder plantations, we studied the litterfall production and its seasonality; temporal variations of nutrient concentrations, stoichiometric ratios and potential nutrient return (PNR) of leaf-litterfall; mean residence times (MRT) of nutrients in the forest floor; and assessed soil biogeochemical properties. Our results showed that total litterfall production in pine was twice as high as in alder. Litterfall biomass seasonality was similar for both species and highly associated to periods with less precipitation. Pine exhibited the highest seasonality of nutrient concentrations and stoichiometric ratios. PNR of N, K, Ca, and Mn exhibited the major differences between the species. The annual PNR of N and Ca were higher in alder, while those of K and Mn were higher in pine. Pine exhibited higher MRT values for C, N, P, S, Cu, and Zn, while alder showed the higher for Mg, K, Mn, and Ca. In soils, alder exhibited higher concentrations and stocks of nutrients, but not for C. Although, the soil microbial biomass was similar under both species, microbial activity was different. C and net N mineralization were higher in alder, and nitrification dominated over ammonification processes. In general, our findings show a faster cycling of nutrients in alder than in pine. [ABSTRACT FROM AUTHOR]

Monitoring long-term forest dynamics is essential for assessing human-induced land-cover changes, and related studies are often based on the multi-decadal Landsat archive. However, in areas such as the Tropical Andes, scarce data and the resulting poor signal-to-noise ratio in time series data render the implementation of automated time-series analysis algorithms difficult. The aim of this research was to investigate a novel approach that combines image compositing, multi-sensor data fusion, and postclassification change detection that is applicable in data-scarce regions of the Tropical Andes, exemplified for a case study in Ecuador. We derived biennial deforestation and reforestation patterns for the period from 1992 to 2014, achieving accuracies of 82 ± 3% for deforestation and 71 ± 3% for reforestation mapping. Our research demonstrated that an adapted methodology allowed us to derive the forest dynamics from the Landsat time series, despite the abundant regional data gaps in the archive, namely across the Tropical Andes. This study, therefore, presented a novel methodology in support of monitoring long-term forest dynamics in areas with limited historical data availability. [ABSTRACT FROM AUTHOR]

Highlights • Socially just governance contributes to the restoration of degraded landscapes. • Remote sensing and ethnographic analyses are combined to explore mangrove change. • Increased mangrove cover (2000–2014) is associated with collective stewardship rights. • Local stewardship values emerged from conflicts between shrimp farmers and fishers. • Stewardship values uphold community-based natural resource management (CBNRM). Abstract Coastal mangrove forests have been undervalued and converted to other uses throughout the developing world for almost half a century. The causes and consequences of mangrove deforestation have been well-documented; however fewer studies have examined the political factors contributing to conservation and the social dimensions of habitat restoration. We combine remote sensing analysis with ethnographic research to quantify patterns of mangrove cover change between 1985 and 2014, and to qualitatively explore local observations and testimonies of conflict over resources in the Jambelí Archipelago, Ecuador. Our results reveal that shrimp aquaculture was a pervasive force shaping spatiotemporal patterns of mangrove cover change from 1985 to 1999. Thereafter, trends of deforestation decelerated to reveal signs of recovery in some locations due to new policies, institutional transformations at multiple levels, and local commitment to community mangrove reforestation. Our research suggests that sustained local commitment to stewardship emerged from local discontent with historically ineffective policies that permitted a struggle between artisanal fishers and shrimp farmers over resources and territory. This context shaped the evolution of policy and provided a ripe environment for successful community-based natural resource management (CBNRM) in 2000 when the Ecuadorian government began granting collective stewardship rights to artisanal fishers and other "ancestral user groups" for mangrove conservation. We conclude that the state's empowerment of artisanal fishers with resource rights served as a critical turning point toward more socially just policies with transformative impacts on previously degraded mangrove landscapes. [ABSTRACT FROM AUTHOR]

As distinct community assembly processes can produce similar community patterns, assessing the ecological mechanisms promoting coexistence in hyperdiverse rainforests remains a considerable challenge. We use spatially explicit neighbourhood models of tree growth to quantify how functional trait and phylogenetic similarities predict variation in growth and crowding effects for the 315 most abundant tree species in a 25-ha lowland rainforest plot in Ecuador. We find that functional trait differences reflect variation in (1) species maximum potential growth, (2) the intensity of interspecific interactions for some species, and (3) species sensitivity to neighbours. We find that neighbours influenced tree growth in 28% of the 315 focal tree species. Neighbourhood effects are not detected in the remaining 72%, which may reflect the low statistical power to model rare taxa and/or species insensitivity to neighbours. Our results highlight the spectrum of ways in which functional trait differences can shape community dynamics in highly diverse rainforests. [ABSTRACT FROM AUTHOR]

The biodiverse montane forests of the tropical Andes are today frequently disturbed by rainfall-driven mass movements which occur mostly during extreme El Niño events. Over the coming decades these events are projected to double under the 1.5 °C global warming scenario. The consequent increased rainfall and mass movement events likely present an elevated risk to millions of people living in the Andes. However, the impact of more frequent rainfall extremes remains unclear due to a lack of studies that directly link past changes in El Niño-Southern Oscillation (ENSO) frequency to forest and landscape disturbance patterns. Here, we present the first Holocene palaeoecological record from Laguna Pallcacocha, southern Ecuador, a key site for El Niño reconstructions. We demonstrate that for the past 10,000 years plant taxa indicative of recolonization – such as Alnus acuminata – covary with El Niño-induced flood layers in the lake. An amplified forest disturbance pattern is observed in the late Holocene, suggesting enhanced slope instability following deforestation. The temporal pattern is not explained by tree line fluctuations or human impact, while the latter does amplify the impact of ENSO on landscape disturbance. Spatial correlations between modern ENSO and precipitation are consistent with a regional comparison of Holocene records of landscape disturbance. Our results indicate that climate extremes, such as those associated with future intensification of El Niño, combined with ongoing land use change will increase the frequency of mass movements elevating risks for millions of people in the Andes. • El Niño-Southern Oscillation (ENSO) dynamics recorded in Lake Pallcacocha, Ecuador. • We test regional impact of ENSO variation on landscape and forest dynamics. • Proxy data mirrors the middle Holocene ENSO intensification seen in flood laminae. • The record shows upper montane forest disturbance linked to landslides. • The record is consistent with other sites that have a strong modern ENSO impact. [ABSTRACT FROM AUTHOR]

Shallow landslides are an important type of natural ecosystem disturbance in tropical montane forests. Due to landslides, vegetation and often also the upper soil layer are removed, and space for primary succession under altered environmental conditions is created. Little is known about how these altered conditions affect important aspects of forest recovery such as the establishment of new tree biomass and species composition. To address these questions we utilize a process-based forest simulation model and develop potential forest regrowth scenarios. We investigate how changes in different trees species characteristics influence forest recovery on landslide sites. The applied regrowth scenarios are: undisturbed regrowth (all tree species characteristics remain like in the undisturbed forest), reduced tree growth (induced by nutrient limitation), reduced tree establishment (due to thicket-forming vegetation and dispersal limitation) and increased tree mortality (due to post-landslide erosion and increased susceptibility). We then apply these scenarios to an evergreen tropical montane forest in southern Ecuador where landslides constitute a major source of natural disturbance. Our most important findings are [(a)] On the local scale of a single landslide tree biomass recovers within the first 80 years after landslides for most scenarios, but it takes at least 200 years for the post-landslide forest to reach a structure (in terms of stem size distribution) similar to a mature forest. On this scale forest productivity is reduced for most regrowth scenarios. Changes in different tree species characteristics produce distinct spatio-temporal patterns of tree biomass distribution in the first decades of recovery within the landslide disturbed area. These patterns can potentially be used for identifying the dominant processes that drive forest recovery on landslide disturbed sites. [(b)] On the larger scale of the landscape overall tree biomass is reduced by 9–15% due to landslide disturbances. Overall forest productivity is only slightly reduced (<6%), but landslides increase landscape heterogeneity and produce hotspots of biomass loss and ‘blind spots’ of forest productivity. Thus landslides have a strong impact on the distribution of biomass in tropical montane forests. This study demonstrates that dynamic forest models are useful tools for complementing field based studies on landslides; they allow for testing alternative hypotheses on different sources of heterogeneity across spatial scales and investigating the influence of landslides on long-term forest dynamics. [Copyright &y& Elsevier]