Tropical Landscapes Research Articles

Climate and forest loss interactively restructure trait composition across a human-modified landscape.

Traits determine species response to climate conditions and the match between phenotypes and climate mediates spatial variation in species composition.These trait-climate linkages can be disrupted in human-modified landscapes. Human land use creates forest fragments where dispersal limitation or edge effects exclude species that may otherwise suit a given macroclimate. Furthermore, stressful macroclimate can limit viable trait combinations such that only a subset of values of any given trait occurs with respect to another trait, resulting in stronger trait covariance. Because forest loss can compound climatic stress, trait covariance from benign to harsher climates is expected to be stronger in fragments compared to contiguous forests. In a wet tropical forest landscape in the Western Ghats Biodiversity Hotspot of peninsular India, I compared fragments with adjacent contiguous forests for signatures of trait-mediated assembly of tree communities. Using four key plant traits-seed size, specific leaf area (SLA), wood density, and maximum height-I evaluated trait-abundance associations and trait covariance across climate, soil, and elevation gradients. In the contiguous forest, smaller-seeded, shorter, thinner-leaved species became more abundant from low to high elevations. In fragments, species with higher SLA were more abundant at sites with more seasonal climates and lower precipitation, and larger seeded species were less abundant at warmer sites. However, traits only weakly predicted abundances in both habitats. Moreover, only contiguous forests exhibited significant compositional change via traits, driven by trait syndromes varying along a composite gradient defined by elevation, water deficit, and soil C:N ratio. Site-level trait covariance revealed that warmer, wetter conditions in fragments favored taller species for given seed size, as compared to similar conditions in contiguous forests. Overall, trait syndromes and trait covariance, rather than single traits, determined the phenotypes best suited to macroclimate conditions and should inform management or restoration goals in fragments.

Configuration and composition of human-dominated tropical landscapes affect the prevalence and average intensity of mite and fly infestation in Phyllostomidae bats.

The conversion of natural areas into agricultural landscapes results in different mosaics of land use types, modifying biodiversity and consequently altering the patterns of ecological interactions, such as between frugivorous bats and ectoparasites. Our objectives were to investigate whether variations in the configuration and composition of human-disturbed landscapes interfere with the prevalence and average intensity of ectoparasite infestation in the frugivorous bats Artibeus lituratus (Olfers, 1818), Carollia perspicillata (Linnaeus, 1758), and Sturnira lilium (É Geoffroy, 1810), in a region of the Brazilian Atlantic Forest. We also evaluated whether there is a response in the parasite load associated with the ectoparasite group (mite or fly). We found six species of flies and three mites. The proportion of infested hosts was more affected by the landscape than the mean infestation values. Land cover diversity influenced seven of the interactions studied. Forest cover affected eight of the interactions and was associated with a reduction in the parasite load in seven of them. The increase in the proportion of edges per area of each fragment presented a different influence related to the host species. Variations in parasite load did not show any typical response related to the mite or fly group. Our study indicates that landscape configuration and composition interfere with bat-ectoparasite interactions, which may be related to interference in encounter rates between hosts (for mites and flies) and between hosts and their ectoparasites in roosts (for flies). The taxonomic identity of the interacting species suggests that the relationship with the landscape is context-dependent.

The role of non‐natural foods in the nutritional strategies of monkeys in a human‐modified mosaic landscape

AbstractMany tropical animals inhabit mosaic landscapes including human‐modified habitat. In such landscapes, animals commonly adjust feeding behavior, and may incorporate non‐natural foods. These behavioral shifts can influence consumers' nutritional states, with implications for population persistence. However, few studies have addressed the nutritional role of non‐natural food. We examined nutritional ecology of wild blue monkeys to understand how dietary habits related to non‐natural foods might support population persistence in a mosaic landscape. We documented prevalence and nutritional composition of non‐natural foods in monkey diets to assess how habitat use influenced their consumption, and their contribution to nutritional strategies. While most energy and macronutrients came from natural foods, subjects focused non‐natural feeding activity on five exotic plants, and averaged about a third of daily calories from non‐natural foods. Most non‐natural food calories came from non‐structural carbohydrates and least from protein. Consumption of non‐natural foods related to time in human‐modified habitats, which two groups used non‐randomly. Non‐natural and natural foods were similar in nutrients, and the amount of non‐natural food consumed drove variation in nutritional strategy. When more daily calories came from non‐natural foods, females consumed a higher ratio of non‐protein energy to protein (NPE:P). Females also prioritized protein while allowing NPE:P to vary, increasing NPE while capitalizing on non‐natural foods. Overall, these tropical mammals achieved a similar nutrient balance regardless of their intake of non‐natural foods. Forest and forest‐adjacent areas with non‐natural vegetation may provide adequate nutrient access for consumers, and thus contribute to wildlife conservation in mosaic tropical landscapes.

Land tenure drives Brazil’s deforestation rates across socio-environmental contexts

Many tropical forestlands are experiencing changes in land-tenure regimes, but how these changes may affect deforestation rates remains ambiguous. Here, we use Brazil’s land-tenure and deforestation data and quasi-experimental methods to analyze how six land-tenure regimes (undesignated/untitled, private, strictly-protected and sustainable-use protected areas, indigenous, and quilombola lands) affect deforestation across 49 spatiotemporal scales. We find that undesignated/untitled public regimes with poorly defined tenure rights increase deforestation relative to any alternative regime in most contexts. The privatization of these undesignated/untitled lands often reduces this deforestation, particularly when private regimes are subject to strict environmental regulations such as the Forest Code in Amazonia. However, private regimes decrease deforestation less effectively and less reliably than alternative well-defined regimes, and directly privatizing either conservation regimes or indigenous lands would most likely increase deforestation. This study informs the ongoing political debate around land privatization/protection in tropical landscapes and can be used to envisage policy aligned with sustainable development goals.

Financial Revenues from Timber Harvesting in Secondary Cloud Forests: A Case Study from Mexico

Secondary forests, i.e., those arising after the clearance and abandonment of previously forested land, dominate tropical forest landscapes, rapidly sequester carbon, provide essential ecosystem services and are prone to re-clearance. Secondary cloud forests (SCF) play a particularly critical role for biodiversity and hydrological regulation. To promote their persistence, sustainable management is necessary; however, there is limited information regarding SCF potential for sustainable timber production. We estimated the revenue from selective timber harvesting in a pilot study in a 20-year-old SCF in Mexico. We explored the effect of the harvested timber volume, harvesting costs and price of forest products on the Net Present Value (NPV). Small landowners could only extract 17% of the harvestable standing volume due to a high number of small trees, a high (34%) volume of non-timber species, and their limited capacity to process timber. A third of the income derived from fuelwood, and overall financial returns were negative. A positive NPV may result from a 20% harvesting intensity, a 10% reduction in harvesting costs, or a 20% increase in stumpage price. Our results warrant the development of forest policy instruments and economic incentives for small-scale SCF landowners to alleviate poverty and meet national and global restoration and climate mitigation goals.

Soundscapes show disruption across the diel cycle in human modified tropical landscapes

1. Fluctuations in the diel cycle, especially when compared across different land-use types, can reveal key changes in acoustic activity and the biological community. Yet few studies have assessed the effects of land use change on soundscapes across the diel cycle. The emergence of passive acoustic monitoring (PAM) allows us to monitor landscapes over longer and continuous periods, providing data on temporal variability across the diel cycle.2. Using AudioMoth acoustic recorders we collected data at 120 sites on the Osa Peninsula, Costa Rica, across a gradient of land use intensity. Information was extracted from recordings using a suite of nine acoustic indices. Principal component analysis reduced the indices into two axes, the first reflecting acoustic activity in the mid frequency bands, where the majority of biotic sound is present, and the second, representing acoustic activity in the upper frequency bands and the ratio of activity between the lower and mid-frequency bands.3. In disturbed land use types we found reduced acoustic activity during the characteristic dawn and dusk peaks in the diel cycle; known as the dawn and dusk chorus. Palm oil plantations showed a complete loss of these peaks, while teak plantations retained evidence of a weaker dawn and dusk chorus. Restricting the analysis to narrower temporal windows masks these differences among habitats.4. Synthesis and applications. Evaluating acoustic diversity at specific times of the day, which is common practice in bioacoustics studies, may be misleading, as pronounced changes in acoustic activity at dawn and dusk were obscured. By assessing trends across the diel cycle, we can gain a much better representation of the changes in acoustic activity. Our results show that in disturbed ecosystems there is a deviation in acoustic activity from that seen in a healthy native forest ecosystem, suggesting that there are likely changes within the biotic community in these ecosystems.

Co-producing theory of change to operationalize integrated landscape approaches

Integrated landscape approaches that engage diverse stakeholder groups in landscape governance are increasingly promoted to address linked social–ecological challenges in tropical landscapes. Recent research suggests that a transdisciplinary approach to landscape management can help identify common research needs, enhance knowledge co-production, guide evidence-based policy development, and harmonize cross-sectorial integration. Meanwhile, guiding principles for landscape approaches suggest that identifying common concerns and negotiating a process of change are fundamental to implementation and evaluation efforts. As such, the use of decision support tools such as theory of change models that build ordered sequences of actions towards a desired, and agreed, future state are increasingly advocated. However, the application of the theory of change concept to integrated landscape approaches is limited thus far, particularly within the scientific literature. Here, we address this gap by applying the principles of landscape approaches and knowledge co-production to co-produce a theory of change to address current unsustainable landscape management and associated conflicts in the Kalomo Hills Local Forest Reserve No. P.13 (KFR13) of Zambia. The participatory process engaged a diverse range of stakeholders including village head people, local and international researchers, district councillors, and civil society representatives amongst others. Several pathways, actions, and interventions were developed around the themes of deforestation, biodiversity and wildlife conservation, socio-economic development, access rights, and law enforcement. To make the theory of change actionable, participants identified a need for enhanced cross-sector and multi-level communication, capacity development, and improved governance, while a lack of commitment towards coordinated knowledge exchange and access to information along with poor policy formulation and weak enforcement of rules were among potential impediments to action. Use of theory of change can both inform evidence-based policy design (by revealing place-based challenges and proposing solutions) and support policy mechanisms that promote integration between state and non-state actors (by clarifying actor rights, roles and responsibilities). Co-developing a theory of change for integrated landscape management is inherently context specific, but the process and outcomes of this study should hold relevance across a range of contexts faced with sustainability challenges related to reconciling both conservation and development objectives.

Soil, Topography and Forest Structure Shape the Abundance, Richness and Composition of Fern Species in the Fragmented Tropical Landscape of Xishuangbanna, Yunnan, China

Understanding how forest fragment size, topography, forest structure, and soil properties affect plant diversity remains a crucial question in conservation biology, with ferns often being understudied. To address this knowledge gap, we surveyed the abundance, species richness, and composition of ferns in a tropical landscape in south China using 75 sites in 42 forest fragments. We then used a multi-model inference approach to assess whether fern abundance, richness, and composition were better explained by (a) fragment size, (b) topography (slope, aspect), (c) forest structure (tree basal area, light availability), or (d) soil properties (pH, Carbon, Nitrogen, Phosphorous, Calcium, Magnesium, water availability, and proportion of clay, silt, and sand). We also conducted a nestedness analysis to examine whether the composition of the fern communities in smaller fragments (0.4–1 km²) differed or represented a subset of the communities found in larger fragments (e.g., >10 km²). We found that (a) fern abundance was mostly influenced by soil properties, slope, and aspect, (b) fern species richness by soil properties and slope, and (c) fern species composition by forest structure, specifically, tree basal area. We also found that fern species composition was not nested in the landscape, suggesting that smaller forest fragments had different communities from larger fragments. Our results suggest also that soil properties play an important role in maintaining fern abundance and diversity and therefore protecting soil can help conserve ferns in fragmented landscapes.

Mapping of Soil Water Erosion and Prioritization of Conservation Measures in the Noun Watershed (West Cameroon Highlands)

Soil erosion is a natural hazard that is exacerbated by human activities in the West Cameroon highlands. However, there is little information on the spatialization of this phenomenon at the territorial scale. This study is based on the use of the Universal Soil Loss Equation (USLE) model and open access data to map areas at risk of erosion and prioritize areas for soil conservation in the Noun watershed. According to the results, 22.61% of the territory is characterized by a low risk of erosion while 77.39% faces a risk of soil loss higher than the tolerable limit of 11 t/ha/year in the context of tropical and mountainous landscapes. This risk is accentuated by the loss of vegetation cover in favor of the expansion of urban and agricultural areas. The low level of sensitivity to erosion is found in the lowlands, while the areas located in the plateaus present a high level of sensitivity due to their rugged terrain and high rainfall. Statistical analysis of landslide frequency ratios shows a relationship between landslide occurrence and erosion intensity zones. Modeling of soil loss as a function of different soil protection methods shows that the strip-grass approach and terracing are the most appropriate for reducing erosion risk in this area. These methods can be combined with afforestation efforts for effective soil protection.

Achieving sustainable water and land use systems in highly developed tropical landscapes

Water quality degradation from human related activities has become a pressing global issue, putting water security at risk around the world. Land use decisions can severely degrade stream water quality, compromising water supply and increasing water treatment costs. Here we examine changes in water quality over 20 years and their association with land use, urbanization, and sewage treatment in the state of São Paulo, Brazil. We also consider how a severe drought in 2014–2015 affected water quality, uncovering the potential impacts of a changing climate on water treatment costs. We analyzed water quality data between 2000 and 2019 from 230 monitoring stations focusing on seven metrics: dissolved oxygen, biological oxygen demand, total nitrogen, total phosphorus, turbidity, total dissolved solids, and fecal coliforms. We first calculated the number of times that metrics exceeded the legal thresholds and then assessed if metrics were improving or deteriorating over time. Across all stations, a large proportion of stream water samples failed to comply to the legal standards for human consumption for at least one water quality metric. This proportion was highest for total dissolved solids (30.7%) and total phosphorus (42.8%), with fewer samples exceeding the threshold for turbidity and dissolved oxygen. Deteriorating water quality trends over time were prevalent for dissolved solids (33.33%) and total nitrogen (52.45%), while dissolved oxygen exhibited the highest percentage of improving trends across watersheds (43.63%). Moreover, we observed that four of the seven metrics analyzed deteriorated during the 2014–2015 drought. Urbanization and agricultural activity led to deterioration of water quality, while improvement in sewage treatment infrastructure improved water quality across watersheds. The decline in water quality observed in the region, especially during the recent drought, highlights the need to develop land use management strategies to protect water quality and reduce growing costs of water treatment in the state.

Edges as hotspots and drivers of forest cover change in a tropical landscape

Forest cover changes are influenced by socioeconomic and biophysical dynamics. However, the relative importance of both social and biophysical factors to forest loss and gain remains in debate. Previous research has focused mainly in identifying determinants of deforestation, while less is known regarding forest regrowth, especially in tropical forests. Here we investigated the spatial pattern and determinants of forest cover changes within a landscape which is representative of the biophysical and socioeconomic conditions found in the Atlantic Forest, and also presents an exceptional conservation value within this global biodiversity hotspot. Events of deforestation and regrowth were identified by comparing land cover maps from aerial images taken in 1975 and 2010. We controlled the spatial autocorrelation among events and used a machine learning algorithm and a selection model approach to build linear models explaining forest loss and gain. Main determinants of both forest loss and gain were biophysical factors, although some of they may also reflect socioeconomic underlying processes. Distance from Strictly Protected Areas (SPAs) was the single socioeconomic determinant important to forest change, in loss events. Both deforestation and forest regrowth were strongly associated with forest edges. Deforestation occurred more intensively on concave or flat areas, low solar radiation conditions, near forests, and far from SPAs. Diversely, forest regrowth occurred mostly in high slopes, low elevation areas, high solar radiation and near to forest edges. Our findings reinforce the important role of topography and protected area on forest change, and highlight edge zones are “hotspots” of forest cover dynamics. .

The Pacific Drought Knowledge Exchange: A Co-Production Approach to Deliver Climate Resources to User Groups

Drought is a growing threat to hydrological, ecological, agricultural, and socio-cultural systems of the tropics, especially tropical islands of the Pacific where severe droughts can compromise food and water security. Overcoming barriers to knowledge sharing between land managers and researchers is a critical cross-sector strategy for engaging and mitigating or adapting to drought. Here we describe the establishment and functioning of the Pacific Drought Knowledge Exchange (PDKE), which provides users with easier access to: (1) sector- and geography-specific climate information; (2) better and more comprehensive information; (3) improved technical assistance; and (4) a more collaborative information-transfer environment through participation in knowledge co-production. We focus on our collaborative work with managers of important tropical dryland ecosystems from three distinct geographies to pilot the collaborative development of climate change, climate variability, and drought “portfolios” featuring site-specific historical and forecasted future information. This information was then used to collaboratively produce factsheets that partners used to: (i) better understand past and projected climate for specific management units; (ii) integrate new climate knowledge into management planning; and (iii) support climate-focused educational and outreach efforts. This pilot effort demonstrates the successful application of climate-focused co-production in dry tropical landscapes.

A review of current knowledge and research priorities for conservation of lentic biodiversity in tropical wet and monsoonal urban landscapes

Abstract Urban expansion is a major threat to diversity, especially in rapidly developing tropical countries where urban areas are growing at great pace and protection is limited. We conducted a systematic review of published research on the ecology of lentic habitats in tropical urban areas. The review focused on understanding: (1) how much is currently known about the biodiversity of these habitats; (2) whether this knowledge is biased towards certain taxonomic groups and/or geographic areas; (3) what is known about the factors influencing their diversity; and (4) which ecosystem services urban lentic habitats provide. The review aimed to establish whether existing knowledge is sufficient to help guide conservation and provide evidence to policy makers of the importance of conserving tropical urban wetlands. We found 64 papers that addressed questions about the diversity and/or distribution of lentic ecosystems within tropical urban areas. Papers came from 15 countries, although almost half (45%) were from India; relatively few countries from Southeast Asia, tropical Africa, or South America were represented in the literature. Publication patterns revealed a growing interest in urban wetlands, but several biases and gaps were evident from the review. Firstly, papers generally focused on larger natural or semi‐natural wetlands, with other types and sizes of lentic habitat under‐represented in published work. Secondly, most papers focused on a single site, with a limited number of multi‐site, city‐wide, or landscape‐scale diversity assessments. Thirdly, studies tended to focus on understanding the influence of water quality on diversity, with work assessing the influence of physical habitat or factors related to dispersal and connectivity very limited. Finally, work assessing the ecosystem services provided by wetlands in tropical urban areas remains narrow in focus, with few quantitative assessments of the relationship between ecological characteristics and ecosystem functions and services. We suggest a number of research focal points and approaches to help address these biases. Research is needed to improve understanding of the distribution patterns tropical freshwater species in urban areas and of the relationships between species diversity and a wider set of environmental and spatial conditions. Overall, there is a need for diversity assessments of tropical urban wetlands of all types and sizes, especially new and novel habitats, and scope for much greater adoption of ecosystem service concepts and evaluation tools to help emphasise the importance of these habitats.

Gamma diversity: derived from and a determinant of alpha diversity and beta diversity. An analysis of three tropical landscapes

Using three taxonomic groups of beetles we examine how alpha and beta diversity influence the species richness of a landscape (gamma diversity), and vice versa. That is, how the species richness of a landscape – which is a historical and biogeographical phenomenon – contributes to the values of alpha diversity (1) at a given site, (2) in a community, (3) in terms of cumulative species richness by community, and also contributes to (4) the intensity of species exchange between communities. To explore this question, we used two subfamilies of Scarabaeoidea: Scarabaeinae and Geotrupinae, and the family Silphidae. In all analyses these three taxonomic groups are considered as a single indicator group: the copronecrophagous beetles. Information is also included on the subfamily Aphodiinae (Scarabaeoidea), coprophagous beetles not included in the indicator group. Several types of vegetation located in three landscapes (tropical, transition and mountain) were studied, and these are located along an altitudinal gradient in the central part of the state of Veracruz, Mexico. We base this study on the following concepts. The alpha diversity of an indicator group reflects the number of species that use a given environment or resource in a given place or community. Spacial beta diversityis related to the response of organisms to spatial heterogeneity. Gamma diversity depends primarily on the historical and geographic processes that operate on the mesoscale level and is also affected by alpha and beta diversity. It is on this scale of landscape that human actions, such as the modification and fragmentation of vegetation, have their most important effects. These are, however, often beyond the scope of ecological analyses carried out on a local scale. In the three landscapes, sampling was carried out regularly at 67 sites, with complementary sampling at another 69 sites. Twenty-six types of vegetation communities were studied. A total of 16,152 specimens representing 60 species were captured (52 species of Scarabaeinae, 4 Geotrupinae and 4 Silphidae). In the tropical landscape the community richest in species was low deciduous forest. In the transition landscape, cloud forest was the richest. Each of these communities is the most representative of their respective altitudinal bands. In contrast, the greatest species richness in the mountain landscape occurred in the mountain grasslands and pastures; types of community favoured by or even created by human intervention. This is explained by the expansion of heliophilous species from the Mexican High Plateau into these areas. In the tropical landscape the species richness of the pastures is similar to that of its forests, but with a partially different composition which is characterized by the dominance of heliophilous and coprophagous species; the latter, in addition to the more ubiquitous species that are shared with the tropical forest. In the transition landscape the cloud forest and the coffee plantations with polyspecific shade are important in the context of conserving the fauna. This type of community offers arboreal cover and occupies the majority of this landscape, allowing the groups of insects studied to move between remnant fragments of cloud forest. On the landscape scale but not locally, the fragmentation of natural communities does not appear to have reduced the number of species for the beetles of the indicator group. In each landscape disturbance by human activity appears to have been overcome for distinct reasons. In the tropical landscape we find the heliophilous beetle fauna characteristic of pastures, and this has increased by two species of recent invaders. In the transition landscape, the coffee plantations with polyspecific shade create a communication matrix, while in the mountain landscape the expansion of the mountain pastures has made conditions more favourable for heliophilous species. These results are not necessarily expected for other groups of organisms.

Habitat amount is a driver for biodiversity, but not for the carbon stock in post-logging natural regenerating areas in Tropical Atlantic Forest

Natural regeneration has been considered an important strategy for improving large-scale forest restoration to revert the losses resulting from the fragmentation of tropical landscapes in recent years. However, local, regional, and spatial factors can influence the dynamics of regeneration, thereby affecting its efficiency. We investigated how time after disturbance, landscape characteristics, and climate gradients affect the efficiency of natural regeneration in the Brazilian Atlantic Forest. We searched for studies that addressed the post-logging regenerating of forests throughout the biome. For each included study, we extracted the forest age, species richness, and basal area (used as an estimate of carbon). Additionally, for each studied site (total 100 sites) we used land use maps to extract the landscape metrics and obtained bioclimatic variables from the global dataset. Further, we used forest age, landscape metrics, and bioclimatic variables to build models and predict forest species richness and carbon stock. Our results showed that species richness was positively affected by habitat amount (evaluated through patch area and perimeter-area ratio), isothermality, and forest age. Carbon stock was positively affected only by the forest age. These findings show that natural regeneration will yield the best results in terms of conserving the biodiversity among landscapes with a large number of habitats. Conversely, a landscape with a predominance of mature forest will be more efficient as carbon stock. We conclude that, when planning the restoration of large-scale landscapes, natural regeneration must be considered along with other strategies to ensure that multiple objectives are achieved.

Unshaded coffee imposes a heavier load on thermoregulation than shaded coffee for birds in a tropical mountainous region

Distribution shifts and local extinctions in tropical montane birds are expected to result from intolerance to elevated temperatures driven by both climate warming and changes in land use which affect local, microclimatic temperatures (Tamic). However, the physiological basis of this phenomenon is yet insufficiently explored. Here, we experimentally measured the response to heat of four wild-caught bird species and predicted how heat exposure would increase the demand for evaporative cooling in a tropical montane region dominated by coffee farming. For this, we first measured Tamic inside shaded and unshaded coffee farms from March to July 2020. Subsequently, we exposed the birds to a temperature gradient in a controlled laboratory environment and measured body temperature and the rates of resting metabolism and evaporative water loss. Using segmented and linear mixed regression models, we determined the temperatures in which these parameters sharply increased (i.e. inflection points). We then used these values to predict the daily amount of time in which Tamic would demand a cooling response and compared it between farm types with generalised linear regression models. Finally, we estimated the water lost to cooling as a percentage of the species-specific body mass. Maximum Tamic in unshaded coffee was significantly higher than in shaded coffee, while Tamic in shaded farms was similar to Tamic inside forest patches used as a reference. The four tested bird species exhibited different rates of change and inflection points of the metabolic parameters. For all of them, shifting from a shaded to an unshaded coffee farm increased the number of hours of exposure by 2–3 times. Inter-specific differences were found in the amount of water predicted to be lost to cooling inside the farms. However, these daily losses, even under the most extreme scenario, represented only a small proportion of body mass lost in the form of water. Taken together, we demonstrate that these four bird species are able to endure the current thermal environment of a tropical montane agricultural landscape, without the risks of chronic or lethal dehydration. Nonetheless, we found that unshaded coffee farms increase the demand for water necessary to maintain water balance over consecutive days, which might become more critical if current scenarios of global warming in the tropics are realised in the future.

Land use and land cover change in a tropical mountain landscape of northern Ecuador: Altitudinal patterns and driving forces

Tropical mountain ecosystems are threatened by land use pressures, compromising their capacity to provide ecosystem services. Although local patterns and interactions among anthropogenic and biophysical factors shape these socio-ecological systems, the analysis of landscape changes and their driving forces is often qualitative and sector oriented. Using the Driver-Pressure-State-Impact-Response (DPSIR) framework, we characterized land use land cover (LULC) dynamics using Markov chain probabilities by elevation and geographic settings and then integrated them with a variety of publicly available geospatial and temporal data into a Generalized Additive Model (GAM) to evaluate factors driving such landscape dynamics in a sensitive region of the northern Ecuadorian Andes. In previous agricultural land located at lower elevations to the east of the studied territory, we found a significant expansion of floriculture (13 times) and urban areas (25 times), reaching together almost 10% of the territory from 1990 to 2014. Our findings also revealed an unexpected trend of páramo stability (0.75-0.90), but also a 40% reduction of montane forests, with the lowest probability (<0.50) of persistence in the elevation band of 2800-3300 m; agricultural land is replacing this LULC classes at higher elevation. These trends highlight the increasing threat of permanently losing the already vulnerable native mountain biodiversity. GAMs of socio-economic factors, demographic, infrastructure variables, and environmental parameters explained between 21 to 42% of the variation of LULC transitions observed in the study region, where topographic factors was the main drivers of change. The conceptual and methodological approach of our findings demonstrate how dynamic patterns through space and time and their explanatory drivers can assist local authorities and decision makers to improve sustainable resource land management in vulnerable landscapes such as the tropical Andes in northern Ecuador.

Win-win opportunities combining high yields with high multi-taxa biodiversity in tropical agroforestry

Resolving ecological-economic trade-offs between biodiversity and yields is a key challenge when addressing the biodiversity crisis in tropical agricultural landscapes. Here, we focused on the relation between seven different taxa (trees, herbaceous plants, birds, amphibians, reptiles, butterflies, and ants) and yields in vanilla agroforests in Madagascar. Agroforests established in forests supported overall 23% fewer species and 47% fewer endemic species than old-growth forests, and 14% fewer endemic species than forest fragments. In contrast, agroforests established on fallows had overall 12% more species and 38% more endemic species than fallows. While yields increased with vanilla vine density and length, non-yield related variables largely determined biodiversity. Nonetheless, trade-offs existed between yields and butterflies as well as reptiles. Vanilla yields were generally unrelated to richness of trees, herbaceous plants, birds, amphibians, reptiles, and ants, opening up possibilities for conservation outside of protected areas and restoring degraded land to benefit farmers and biodiversity alike.

Landscape conservation as a strategy for recovering biodiversity: Lessons from a long‐term program of pasture restoration in the southern Atlantic Forest

Abstract Although ecological restoration has entered the global agenda to reverse different anthropogenic disturbances, we still know little about how this solution interacts with other conservation strategies, to avoid the progressive loss of species and ecosystem services. Here we evaluate one of the pioneering restoration programs in the southern Brazilian Atlantic Forest, where the combination of conservation and restoration efforts has been carried out for 20 years. Specifically, we tested how landscape characteristics, restoration strategies and environmental characteristics affect the results of the restoration of pastures. We established 65 circular plots (total 4.0 ha) along restoration areas (3–10 years) and sampled trees and shrubs composing the canopy (DBH ≥ 5 cm) and understorey (DBH &lt; 5 cm, height &gt; 1.3 m). We analysed the landscape metrics (proportion of old‐growth forests in 200, 500 and 1,000 m buffers around each plot; and area and distance of the nearest‐neighbouring old‐growth forests). We explored the multiple effects of landscape, restoration strategy (reforestation, natural regeneration) and environmental variables (soil, pasture grass types) on the species composition and multiple diversity metrics of restoration areas. The species composition was very similar among restoration ages and restoration strategies. We found positive and strong effects of old‐growth forest (200 m buffer) proportion on the species richness and Shannon diversity (canopy and understorey), above‐ground biomass (canopy) and functional diversity (understorey) of restoration areas. The restoration strategies affected forest structure, and, in general, the reforestation strategy increased above‐ground biomass, Shannon, functional and phylogenetic diversities (in canopy), and percentage of endemic species and biomass (understorey), when compared to natural regeneration. The 20‐year experience in the southern Atlantic Forest showed that programs focused on landscape conservation associated with a mixture of restoration strategies (i.e. natural regeneration in larger areas and active restoration in more disturbed sites), can be an efficient strategy to ensure biodiversity and ecosystem services in tropical landscapes. Synthesis and applications. To manage degraded tropical lands and achieve global targets for biodiversity and ecosystem services, it is necessary to first ensure the conservation of natural remnants and then use multiple restoration strategies in less resilient areas.

Climatic and edaphic‐based predictors of normalized difference vegetation index in tropical dry landscapes: A pantropical analysis

AbstractAimSpatial patterns in resource supply drive variability in vegetation structure and function, yet quantification of this variability for tropical dry forests (TDFs) remains rudimentary. Several climate‐driven indices have been developed to classify and delineate TDFs globally, but there has not been a climo‐edaphic synthesis of these indices to assess and delineate the extent of TDFs. A statistical climo‐edaphic synthesis of these indices is therefore required.LocationPantropical.Time periodModern.Major taxa studiedVascular plants.MethodsWe assembled most known prior descriptions of TDFs into a single data layer and assessed statistically how the TDF biome, which we call tropical dry landscapes (TDLs) composed of forest and non‐forest vegetation, varied with respect to the normalized difference vegetation index (NDVI) sensed by MODIS (250 m pixel resolution). We examined how the NDVI varied with respect to mean annual temperature (MAT) and rainfall (MAR), precipitation regime, evapotranspiration and the physical, chemical and biological properties of TDL soils.ResultsOverall, the NDVI varied widely across TDLs, and we were able to identify five principal NDVI categories. A regression tree model captured 90% of NDVI variation across TDLs, with 14 climate and soil metrics as predictors. The model was then pruned to use only the three strongest metrics. These included the Lang aridity index, total evapotranspiration (ET) and MAT, which aligned with identified NDVI thresholds and accounted for 70% of the variation in NDVI. We found that across a global TDL distribution, ET was the strongest positive predictor and MAT the strongest negative predictor of the NDVI.Main conclusionsThe remote sensing‐based approach described here provides a comprehensive and quantitative biogeographical characterization of global TDL occurrence and the climatic and edaphic drivers of these landscapes.