Fernando Casanoves

The global spectrum of plant form and function

Earth is home to a remarkable diversity of plant forms and life histories, yet comparatively few essential trait combinations have proved evolutionarily viable in today’s terrestrial biosphere. By analysing worldwide variation in six major traits critical to growth, survival and reproduction within the largest sample of vascular plant species ever compiled, we found that occupancy of six-dimensional trait space is strongly concentrated, indicating coordination and trade-offs. Three-quarters of trait variation is captured in a two-dimensional global spectrum of plant form and function. One major dimension within this plane reflects the size of whole plants and their parts; the other represents the leaf economics spectrum, which balances leaf construction costs against growth potential. The global plant trait spectrum provides a backdrop for elucidating constraints on evolution, for functionally qualifying species and ecosystems, and for improving models that predict future vegetation based on continuous variation in plant form and function.

PATTERNS OF ANIMAL DIVERSITY IN DIFFERENT FORMS OF TREE COVER IN AGRICULTURAL LANDSCAPES

As tropical regions are converted to agriculture, conservation of biodiversity will depend not only on the maintenance of protected forest areas, but also on the scope for conservation within the agricultural matrix in which they are embedded. Tree cover typically retained in agricultural landscapes in the neotropics may provide resources and habitats for animals, but little is known about the extent to which it contributes to conservation of animal species. Here, we explore the animal diversity associated with different forms of tree cover for birds, bats, butterflies, and dung beetles in a pastoral landscape in Nicaragua. We measured species richness and abundance of these four animal taxa in riparian and secondary forest, forest fallows, live fences, and pastures with high and low tree cover. We recorded over 20,000 individuals of 189 species including 14 endangered bird species. Mean abundance and species richness of birds and bats, but not dung beetles or butterflies, were significantly different among forms of tree cover. Species richness of bats and birds was positively correlated with tree species richness. While the greatest numbers of bird species were associated with riparian and secondary forest, forest fallows, and pastures with >15% tree cover, the greatest numbers of bat species were found in live fences and riparian forest. Species assemblages of all animal taxa were different among tree cover types, so that maintaining a diversity of forms of tree cover led to conservation of more animal species in the landscape as a whole. Overall, the findings indicate that retaining tree cover within agricultural landscapes can help conserve animal diversity, but that conservation efforts need to target forms of tree cover that conserve the taxa that are of interest locally. Preventing the degradation of remaining forest fragments is a priority, but encouraging farmers to maintain tree cover in pastures and along boundaries may also make an important contribution to animal conservation.

Does functional trait diversity predict above-ground biomass and productivity of tropical forests? Testing three alternative hypotheses

Summary 1. Tropical forests are globally important, but it is not clear whether biodiversity enhances carbon storage and sequestration in them. We tested this relationship focusing on components of functional trait biodiversity as predictors. 2. Data are presented for three rain forests in Bolivia, Brazil and Costa Rica. Initial above-ground biomass and biomass increments of survivors, recruits and survivors + recruits (total) were estimated for trees ≥10 cm d.b.h. in 62 and 21 1.0-ha plots, respectively. We determined relationships of biomass increments to initial standing biomass (AGBi), biomass-weighted community mean values (CWM) of eight functional traits and four functional trait variety indices (functional richness, functional evenness, functional diversity and functional dispersion). 3. The forest continuum sampled ranged from ‘slow’ stands dominated by trees with tough tissues and high AGBi ,t o‘fast’ stands dominated by trees with soft, nutrient-rich leaves, lighter woods and lower AGBi. 4. We tested whether AGBi and biomass increments were related to the CWM trait values of the dominant species in the system (the biomass ratio hypothesis), to the variety of functional trait values (the niche complementarity hypothesis), or in the case of biomass increments, simply to initial standing biomass (the green soup hypothesis). 5. CWMs were reasonable bivariate predictors of AGBi and biomass increments, with CWM specific leaf area SLA, CWM leaf nitrogen content, CWM force to tear the leaf, CWM maximum adult height Hmax and CWM wood specific gravity the most important. AGBi was also a reasonable predictor of the three measures of biomass increment. In best-fit multiple regression models, CWM Hmax was the most important predictor of initial standing biomass AGBi. Only leaf traits were selected in the best models for biomass increment; CWM SLA was the most important predictor, with the expected positive relationship. There were no relationships of functional variety indices to biomass increments, and AGBi was the only predictor for biomass increments from recruits. 6. Synthesis. We found no support for the niche complementarity hypothesis and support for the green soup hypothesis only for biomass increments of recruits. We have strong support for the biomass ratio hypothesis. CWM Hmax is a strong driver of ecosystem biomass and carbon storage and CWM SLA, and other CWM leaf traits are especially important for biomass increments and carbon sequestration.

Functional biogeography of oceanic islands and the scaling of functional diversity in the Azores

Significance Biogeographic theory builds upon a long history of analyzing species-diversity patterns of remote islands, but no previous studies have attempted to investigate corresponding patterns in functional traits on islands. Our analyses of functional diversity (FD) for spiders and beetles in the Azorean archipelago reveal that FD increases with species richness, which, in turn scales with island area regardless of the taxa and distributional group considered (endemics, natives, and exotics). Our results also support the hypothesis that each group contributes to FD in proportion to their species richness and that, being dominant, exotic species have significantly extended the realized trait space of the Azorean islands. Further analyses in other archipelagos are needed to establish whether our findings are representative of oceanic islands. Analyses of species-diversity patterns of remote islands have been crucial to the development of biogeographic theory, yet little is known about corresponding patterns in functional traits on islands and how, for example, they may be affected by the introduction of exotic species. We collated trait data for spiders and beetles and used a functional diversity index (FRic) to test for nonrandomness in the contribution of endemic, other native (also combined as indigenous), and exotic species to functional-trait space across the nine islands of the Azores. In general, for both taxa and for each distributional category, functional diversity increases with species richness, which, in turn scales with island area. Null simulations support the hypothesis that each distributional group contributes to functional diversity in proportion to their species richness. Exotic spiders have added novel trait space to a greater degree than have exotic beetles, likely indicating greater impact of the reduction of immigration filters and/or differential historical losses of indigenous species. Analyses of species occurring in native-forest remnants provide limited indications of the operation of habitat filtering of exotics for three islands, but only for beetles. Although the general linear (not saturating) pattern of trait-space increase with richness of exotics suggests an ongoing process of functional enrichment and accommodation, further work is urgently needed to determine how estimates of extinction debt of indigenous species should be adjusted in the light of these findings.

Quantifying Functional Biodiversity

1. Introduction 1.1 Functional Diversity Approach To Quantify the Biodiversity 1.2 Functional Diversity Assessment 1.3 Classification of Ecosystem Services 1.4 Selection of Traits According to Ecosystem Service 1.5. Functional Diversity Quantification 2. Functional Groups 2.1 Selecting Trait and Its Relation With Ecosystem Services 2.2 A Guide For Data Arrangement 2.3 Statistical Procedures To Define Functional Groups 2.3.1 The Selection of a Dissimilarity Measure 2.3.2 Standardization 2.3.3 Choosing the Linkage Algorithm Method 2.3.4 Assessing the Number of Functional Groups 2.4 Functional Characterization of Coastal Sandy Plain Vegetation in Southeast Brazil 2.4.1 The Data Set 2.4.2 Plant Functional Types From a Restinga Vegetation 2.5 Functional Groups For Bird Species in Nicaragua 2.5.1 The Data Set 2.5.2 Bird Functional Types From Nicaragua 2.5.3 Characterization of Bird Functional Types of Nicaragua 2.5.4 Relationship of Functional Types With Land Uses 3. Functional Diversity Indices 3.1 About Functional Diversity Indices and Measures 3.2 Species Diversity Indices 3.3 Single-trait Metrics and Indices: Properties and Estimation 3.3.1 Community Weighted Mean 3.3.2 Functional Divergence 3.3.3 Functional Regularity 3.4 Multi-trait Indices: Properties and Estimation 3.4.1 Functional Attribute Diversity 3.4.2 Functional Diversity Based on Dendrograms 3.4.3 Convex Hull Hyper-volume 3.4.4. Quadratic Entropy 3.4.5 Extended FD 3.4.6 Functional Richness, Evenness, Divergence and Dispersion 3.5 Ability of Indices to Detect Some Ecological Processes 4. How To Estimate Functional Diversity Indices 4.1 The FDiversity Software: Capabilities and Data Management 4.1.1 How To Install FDiversity 4.1.2 Data Menu 4.1.3 Statistics and Output Menus 4.2 Case study: Changes in Functional Diversity in an Altitudinal Gradient 4.2.1 Sample Design and Trait Evaluation 4.2.2 The Database 4.2.3 Changes of Plant Functional Types With the Altitude 4.2.4 Changes of Functional Diversity Indices With the Altitude 4.3 Case study: Changes in Functional Diversity in a Chronosequence 4.3.1 Sample Design and Trait Evaluation 4.3.2 The Database 4.3.3 Changes of Plant Functional Types in the Chronosequence 4.4 Multivariate Graphical Projection Methods Index Index

More Stable Productivity of Semi Natural Grasslands than Sown Pastures in a Seasonally Dry Climate

In the Neotropics the predominant pathway to intensify productivity is generally thought to be to convert grasslands to sown pastures, mostly in monoculture. This article examines how above-ground net primary productivity (ANPP) in semi-natural grasslands and sown pastures in Central America respond to rainfall by: (i) assessing the relationships between ANPP and accumulated rainfall and indices of rainfall distribution, (ii) evaluating the variability of ANPP between and within seasons, and (iii) estimating the temporal stability of ANPP. We conducted sequential biomass harvests during 12 periods of 22 days and related those to rainfall. There were significant relationships between ANPP and cumulative rainfall in 22-day periods for both vegetation types and a model including a linear and quadratic term explained 74% of the variation in the data. There was also a significant correlation between ANPP and the number of rainfall events for both vegetation types. Sown pastures had higher ANPP increments per unit rainfall and higher ANPP at the peak of the rainy season than semi-natural grasslands. In contrast, semi-natural grasslands showed higher ANPP early in the dry season. The temporal stability of ANPP was higher in semi-natural grasslands than in the sown pastures in the dry season and over a whole annual cycle. Our results reveal that, contrary to conventional thinking amongst pasture scientists, there appears to be no increase in ANPP arising from replacing semi-natural grasslands with sown pastures under prevailing pasture management practices in seasonally dry climates, while the temporal distribution of ANPP is more even in semi-natural grasslands. Neither sown pastures nor semi-natural grasslands are productive towards the end of the dry season, indicating the potential importance of the widespread practice of retaining tree cover in pastures.

Shrub biomass estimation in the semiarid Chaco forest: a contribution to the quantification of an underrated carbon stock

ContextThe quantification of biomass of woody plants is at the basis of calculations of forest biomass and carbon stocks. Although there are well-developed allometric models for trees, they do not apply well to shrubs, and shrub-specific allometric models are scarce. There is therefore a need for a standardized methodology to quantify biomass and carbon stocks in open forests and woodlands.AimsTo develop species-specific biomass estimation models for common shrubs, as well as a multispecies shrub model, for the subtropical semiarid Chaco forest of central Argentina.MethodsEight shrub species (Acacia aroma, Acacia gilliesii, Aloysia gratissima, Capparis atamisquea, Celtis ehrenbergiana, Larrea divaricata, Mimozyganthus carinatus, and Moya spinosa) were selected, and, on average, 30 individuals per species were harvested. Their total individual dry biomass was related with morphometric variables using regression analysis.ResultsCrown area as well as crown-shaped variables proved to be the variables with the best performance for both species-specific and multispecies shrub models. These allometric variables are thus recommended for standardized shrub biomass assessments.ConclusionBy accounting for the shrub component of the vegetation, our models provide a way to improve the quantification of biomass and carbon in semiarid open forest and woodlands.

Selection of forest species for the rehabilitation of disturbed soils in oil fields in the Ecuadorian Amazon

Abstract Soils in the Amazon Basin disturbed by petroleum extraction activities need to be restored to allow for the rehabilitation of these areas and the restoration of the ecosystem services that they can provide. This study explores the performance of saplings of 20 species transplanted to four sites: a paddock and three sites within oil fields that differ in soil substrate contamination and perturbation. In each site we measured sapling survival, possible causes of death, sapling height and diameter at the time of and two years after planting, and the integrated response index. We also analyzed the effects of plants on soil properties. Sapling mortality was limited, with 17 of the 20 species boasting survival rates of over 80%. Saplings in the control site had a higher mortality rate than those in the oil field sites. This was most likely due to competition with and interference of weeds that were more abundant at the control than other sites. Despite the overall low mortality rate, species performance did vary by site, with plants of Flemingia macrophylla, Myrcia aff. fallax, Piptadenia pteroclada, Platymiscium pinnatum, and Zygia longifolia exhibiting the best performance in terms of survival and growth in oil field sites. At the end of the experiment, soil substrates from the oil platform showed increases in pH levels, organic material, Fe, and Zn; whereas substrates contaminated with petroleum showed decreases in hydrocarbon levels ranging from 11 to 22% compared to initial levels before sapling transplanting. Our results shed light on which forest species are most suitable for the rehabilitation of sites disturbed by activities inherently associated with petroleum extraction in the Ecuadorian Amazon.

Determinants of rain-forest floristic variation on an altitudinal gradient in southern Costa Rica

Thedegreetowhichgeographicallocationratherthanenvironmentaffectsthemaintenanceofhightropical forest beta diversity on altitudinal gradients is not well understood. Forest composition and its relationship to climate, soil, altitude and geographical distance were determined across an 1114-km 2 landscape in south Pacific Costa Rica spanning an altitudinal gradient (0-1500 m asl). In 37 0.25-ha plots, > 200 species of dicot trees (≥ 30 cm dbh) and canopy palms (≥ 10 cm dbh) were found. Ordination analysis showed strong species composition patterns related to altitude; plot coordinates on the main axis showed negative correlations to the abundance of lowland-forest species Iriartea deltoidea (r =− 0.54) and Brosimum utile (r =− 0.65), and positive correlations to higher-altitude species Alchornea glandulosa (r = 0.63), Quercus sp. (r = 0.50) and Ocotea sp. 2 (r = 0.48). Mantel correlations, correlograms andvariationpartitioninganalysisofrelationshipsbetweenfloristiccompositionandspatialandenvironmentalfactors indicated that spatial location of the plots - potentially, dispersal limitation - was the single most important (R 2 adj = 0.149) driver of beta diversity, but that environmental heterogeneity also plays an important role. In particular, palm speciesturnoverwasstronglyrelatedtosoilchemicalproperties.Theeffectsofdispersallimitationonfloristicassembly could determine the future distribution of plant communities as a result of climate change.

Consistency in bird use of tree cover across tropical agricultural landscapes

In tropical regions where forests have been replaced by agriculture, the future of biodiversity is increasingly dependent on the presence of remnant forest patches and on-farm tree cover within agricultural landscapes. While there is growing evidence of the importance of tree cover within agricultural landscapes, most studies have been conducted in a single landscape, making it difficult to ascertain whether the conservation value of different types of tree cover can be generalized across landscapes. To explore whether use of different forms of tree cover by birds is consistent across landscapes, we compared the number of individuals, species richness, and diversity of birds associated with different forms of tree cover in four agricultural landscapes in Central America, using a standardized methodology and sampling effort. In each landscape, we compared bird assemblages in six tree cover types (secondary forests, riparian forests, forest fallows, live fences, pastures with high tree cover, and pastures with low tree cover). We observed a total of 10 723 birds of 283 species, with 83-196 species per landscape. The specific patterns of bird species richness, number of individuals, and diversity associated with tree cover types varied across the four landscapes, but these variables were consistently higher in the forest forms of tree cover (riparian forests, secondary forests, and forest fallows) than in non-forest habitats. In addition, forest forms of tree cover had distinct species composition from non-forest forms in all landscapes. There was also consistency in the use of different types of tree cover by forest birds across the four landscapes, with higher richness and number of individuals of forest birds in forested than non-forested forms of tree cover, and more forest bird species in pastures with high tree cover than in pastures with low tree cover. Our findings indicate that riparian and secondary forests are consistently of higher value for bird conservation (particularly for forest species) than live fences and pastures with tree cover. Consequently, agricultural and land use policies that promote the retention of secondary and riparian forests and increase tree cover within pastures would greatly benefit bird conservation, regardless of the landscape in which they are applied.