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Abstract: Species are often controlled by biotic factors such as competition at the warm edge of their distribution range. Disturbances at the treeline, disrupting competitive dominance, may thus enable alpine species to utilize lower altitudes. We searched for evidence for range expansion in grazed, fire‐managed Ethiopian subalpine Erica heathlands across a 25‐year chronosequence. We examined vascular plant composition in 48 plots (5 × 5 m) across an altitudinal range of 3,465–3,711 m.a.s.l. and analyzed how community composition changed in relation to increasing competition over time (using a Shade index based on Erica shrub height and cover) and altitude. Species‘ habitats and altitudinal ranges were derived from literature. Time since fire explained more variation (r2 = .41) in species composition than altitude did (r2 = .32) in an NMDS analysis. Community‐weighted altitudinal optima for species in a plot decreased strongly with increasing shade (GLM, Standardized Regression Coefficient SRC = −.41, p = .003), but increased only weakly with altitude (SRC = .26, p = .054). In other words, young stands were dominated by species with higher altitudinal optima than old stands. Forest species richness increased with Log Shade index (SRC = .12, p = .008), but was unaffected by altitude (SRC = −.07, p = .13). However, richness of alpine and heathland species was not highest in plots with lowest Shade index, but displayed a unimodal pattern with an initial increase, followed by a decrease when shading increased (altitude was not significant). Our results indicate that disturbance from the traditional patch burning increases the available habitat for less competitive high‐altitude plants and prevents tree line ascent. Therefore, maintaining, but regulating, the traditional land use increases the Afro‐alpine flora's resilience to global warming. However, this system is threatened by a new REDD+ program attempting to increase carbon storage via fire suppression. This study highlights the importance of understanding traditional management regimes for biodiversity conservation in cultural landscapes in an era of global change. [ABSTRACT FROM AUTHOR]

Tropical agroforestry systems provide farmers with resources for their livelihoods, but are also well‐recognized as refuges for biodiversity. However, the relationship between yield and biodiversity might be negative in these systems, reflecting a potential trade‐off between managing for increased yield or biodiversity. The potential for synergies will depend partly on the shape of the biodiversity–yield relationship, where a concave relationship suggests a faster decline in biodiversity with increasing yields than a linear or convex shape.We studied the relationship between biodiversity (plant species richness and composition) and coffee yield along a gradient of management in south‐western Ethiopia, coffee's native range. We inventoried species richness and community composition of woody plants, herbaceous plants and bryophytes at 60 sites. We also measured coffee management‐related variables and assessed coffee yield for 3 consecutive years at each site.Species richness of woody plants had a concave relationship with coffee yield, that is, tree richness declined fast initially before levelling out at higher yields, whereas there was no relationship between coffee yield and species richness of herbaceous plants or bryophytes. Species composition of woody plants, herbaceous plants and bryophytes all had a concave relationship with coffee yield.From a methodological perspective, we found that multi‐year data on yield were necessary to reliably assess the relationship between biodiversity and yield, and that the number of coffee shrubs or coffee dominance were poor proxies for yield when trying to capture the biodiversity–yield relationship.Synthesis and applications. The concave relationship between biodiversity components (species richness and composition) and yield suggests that there is a strong conflict between the goals of increasing production and conserving biodiversity. However, it is important to recognize that this pattern is largely driven by the very low‐yielding sites in natural forests. Here, even minor intensification of coffee management seems to rapidly erode biodiversity. Along the rest of the productivity gradient, there was generally no negative relationship between yield and biodiversity, implying opportunities for developing strategies for increasing yields without biodiversity loss. [ABSTRACT FROM AUTHOR]

High tropical mountains harbour remarkable and fragmented biodiversity thought to a large degree to have been shaped by multiple dispersals of cold-adapted lineages from remote areas. Few dated phylogenetic/phylogeographic analyses are however available. Here, we address the hypotheses that the sub-Saharan African sweet vernal grasses have a dual colonization history and that lineages of independent origins have established secondary contact. We carried out rangewide sampling across the eastern African high mountains, inferred dated phylogenies from nuclear ribosomal and plastid DNA using Bayesian methods, and performed flow cytometry and AFLP (amplified fragment length polymorphism) analyses. We inferred a single Late Pliocene western Eurasian origin of the eastern African taxa, whose high-ploid populations in one mountain group formed a distinct phylogeographic group and carried plastids that diverged from those of the currently allopatric southern African lineage in the Mid- to Late Pleistocene. We show that Anthoxanthum has an intriguing history in sub-Saharan Africa, including Late Pliocene colonization from southeast and north, followed by secondary contact, hybridization, allopolyploidization and local extinction during one of the last glacial cycles. Our results add to a growing body of evidence showing that isolated tropical high mountain habitats have a dynamic recent history involving niche conservatism and recruitment from remote sources, repeated dispersals, diversification, hybridization and local extinction. [ABSTRACT FROM AUTHOR]

Human population expansion and associated degradation of the habitat of many wildlife species cause loss of biodiversity and species extinctions. The small Simen Mountains National Park in Ethiopia is one of the last strongholds for the preservation of a number of afro-alpine mammals, plants and birds, and it is home to the rare endemic Walia ibex, Capra walie. The narrow distribution range of this species as well as potential competition for resources with livestock, especially with domestic goat, Capra hircus, may compromise its future survival. Based on a curated afro-alpine taxonomic reference library constructed for plant taxon identification, we investigated the diet of the Walia ibex and addressed the dietary overlap with domestic goat using DNA metabarcoding of faecal samples. Faeces of both species were collected from different localities in the National Park. We show that both species are browsers, with forbs, shrubs and trees comprising the largest proportion of their diet, supplemented by grasses. There was a considerable overlap in dietary preferences. Several of the preferred diet items of the Walia ibex (Alchemilla sp., Hypericum revolutum, Erica arborea and Rumex sp.) were also among the most preferred diet items of the domestic goat. These results indicate that there is potential for competition between the two species, especially during the dry season, when resources are limited. Our findings, in combination with the expected increase in domestic herbivores, suggest that management plans should consider the potential threat posed by domestic goats to ensure future survival of the endangered Walia ibex. [ABSTRACT FROM AUTHOR]

• Local and landscape processes drive woody plant regeneration in coffee agroforestry. • Regeneration decreased with higher local management intensity. • Seedling species richness and diversity declined with distance to intact forest. • Microclimate and seed dispersal are potential mechanisms behind these patterns. • Conservation approaches require both a local and landscape perspective. With the current deforestation rates in tropical ecosystems, optimizing biodiversity in managed systems has become fundamental for conservation. Agroforestry has been suggested to conserve biodiversity and buffer deforestation rates, while also sustaining local livelihoods. While many studies have focused on the relation between local management intensity and biodiversity, processes at the landscape scale are often overlooked and remain a knowledge gap. In this study we identified drivers behind woody plant regeneration in coffee agroforestry on both local and landscape scale. We used univariate-, multivariate- and structural equation models to relate seedling species richness, diversity, density, community composition and height to local management intensity and location in the landscape of 60 coffee agroforestry sites in southwestern Ethiopia. Local management intensity, which simplifies and reduces canopy cover, negatively impacted species richness, diversity and density, presumably due to altered microclimatic conditions and a reduction in local seed sources. Seedling height was also reduced by management intensity, including slashing frequency and canopy cover. On the landscape scale, species richness and diversity of seedlings was higher at sites adjacent to continuous forests where seed sources are abundant, and declined with distance to the forest. In particular, late successional species were negatively affected, whereas common shade tree species and pioneers occurred as seedlings throughout the landscape and in more managed systems. This suggests that dispersal limitation is detrimental for the regeneration of late successional species, especially in agroforestry systems where the standing woody plant diversity is largely reduced. Our results indicate that natural regeneration of woody plants still occurs in coffee agroforestry systems, primarily when the canopy structure is dense and diverse and/or when sites are located nearby continuous forests. Management intensification and deforestation will limit the potential for many woody plant species to regenerate in coffee agroforestry sites, by altering the local microclimate, reducing local seed sources and disrupting seed dispersal from the surrounding landscape. This will likely result in a positive feedback loop, as a reduction in woody plant regeneration reduces future seed sources. We therefore stress that both a local and a landscape perspective should be incorporated in conservation and restoration approaches. [ABSTRACT FROM AUTHOR]