Experimental studies are needed to empirically examine the effects of climate change on terrestrial organisms and to serve as the basis for predictions and management practices. As such, designing and implementing experimental systems that can simulate complex changes in the natural environment is currently a major area of interest of climate change science. Most climate change experiments (e.g., infrared heaters, open-top chambers) are typically performed within small, controlled environments and often manipulate just temperature and/or CO₂ concentration. Other factors are more difficult to control (e.g., wind speed, soil moisture) or are frequently ignored (e.g., biotic interactions), leading to uncertainties in the results and limiting our ability to make realistic predictions about species’ responses to future environmental changes. We examined the natural variation of abiotic and biotic factors along mountain elevational gradients in order to highlight the potential for using these systems as natural laboratories for climate change research and experiments. The high variability of different abiotic and biotic factors along elevational gradients provides a good opportunity to carry out field transplant/translocation experiments aimed at answering some critical questions, including: How will new biotic assemblages affect key interactions and processes? What are the factors that influence species assemblages under novel climates? How do local abiotic factors influence the establishment of species migrating into novel and climatically suitable habitats? Based on empirical evidence, we strongly encourage researchers to take advantage of the natural environmental gradients found in mountains to study the potential direct and indirect impacts of climate change on species, communities and biodiversity as a whole.

Tree growth response across environmental gradients is fundamental to understanding species distributional ecology and forest ecosystem ecology and to predict future ecosystem services. Cross‐sectional patterns of ecosystem properties with respect to climatic gradients are often used to predict ecosystem responses to global change. Across sites in the tropics, primary productivity increases with temperature, suggesting that forest ecosystems will become more productive as temperature rises. However, this trend is confounded with a shift in species composition and so may not reflect the response of in situ forests to warming. In this study, we simultaneously studied tree diameter growth across the altitudinal ranges of species within a single genus across a geographically compact temperature gradient, to separate the direct effect of temperature on tree growth from that of species compositional turnover. Using a Bayesian state space modeling framework we combined data from repeated diameter censuses and dendrometer measurements from across a 1700‐m altitudinal gradient collected over six years on over 2400 trees inWeinmannia, a dominant and widespread genus of cloud forest trees in the Andes. Within species, growth showed no consistent trend with altitude, but higher‐elevation species had lower growth rates than lower‐elevation species, suggesting that species turnover is largely responsible for the positive correlation between productivity and temperature in tropical forests. Our results may indicate a significant difference in how low‐ and high‐latitude forests will respond to climate change, since temperate and boreal tree species are consistently observed to have a positive relationship between growth and temperature. If our results hold for other tropical species, a positive response in ecosystem productivity to increasing temperatures in the Andes will depend on the altitudinal migration of tree species. The rapid pace of climate change, and slow observed rates of migration, suggest a slow, or even initially negative response of ecosystem productivity to warming. Finally, this study shows how the observed scale of biological organization can affect conclusions drawn from studies of ecological phenomena across environmental gradients, and calls into question the common practice in tropical ecology of lumping species at higher taxonomic levels.

Food security and biodiversity conservation are threatened by the emergence and spread of pest and pathogens, and thus there is a current need to develop pest management strategies that are sustainable and friendly to the environment and human health. Here, we performed laboratory and field bioassays to evaluate the insecticidal effects of several concentrations of capsaicinoids and glucosinolates (separately and mixed) on an aphid pest (Aphis cytisorum). The capsaicinoids were extracted from the fruits of Capsicum chinense and glucosinolates from the tubers of native Andean crop Tropaeolum tuberosum. We found that both capsaicinoids and glucosinolates have a biocidal effect on A. cytisorum, acting within a fairly short time. Under laboratory conditions, the toxicity of the compounds increased in relation to their concentrations, causing a high percentage of mortality (83–99%) when the aphids were exposed to dilutions of 10% capsaicinoids, 75–100% glucosinolates, or a mixture of 10% capsaicinoids and 90% glucosinolates. The mortality of aphids sprayed in the field with 5% capsaicinoids, 50% glucosinolates, or with a mixture of 5% capsaicinoids and 45% glucosinolates reached 87–97%. Results obtained from laboratory and field experiments were consistent. Our results suggest the potential use of bioinsecticides based on capsaicinoids and/or glucosinolates as an effective alternative to synthetic pesticides.

While tropical forests are undergoing rapid transformation as a result of direct human impacts, many deforested areas are reverting to forest through natural or human-assisted regeneration. This situation provides a window of opportunity to implement forest management strategies to achieve environmental objectives while promoting social development and contributing to local livelihoods. Successful forest management policy, however, depends on how well we can appraise environmental consequences as well as on the value of ecosystem services that these regrowing forests provide. Here, we review the published literature to synthesize the ecosystem services provided by three types of forest transitions: naturally-regenerated secondary forests, agroforestry systems, and tree plantations, in the coastal, Andean, and Amazonian regions of Peru. We then discuss the potential of these regrowing forests as nature-based solutions that can help in the adoption of policies that promote their sustainable use and conservation. Our literature analysis reveals that forest transitions provide significant services in offsetting carbon emissions, providing habitats for biodiversity, and regulating hydrological services. However, the amount and importance of ecosystem services vary depending on the forest transition type. Secondary forests offer multiple services, representing a low-cost, immediate, and highly effective strategy in mitigating the climate and biodiversity crises and ultimately providing vital ecosystem services to society, such as water provision. In contrast, exotic tree plantations have negative effects on water regulation services. We highlight the potential of secondary forests for land management that supports multiple and integrated environmental initiatives. This framework can guide policy decisions to choose appropriate options on forest transition types most suitable to achieve specific end goals at local and regional scales, considering both ecosystem services and disservices to avoid trade-offs in which the achievement of one goal is detrimental to another.