Resource Conservation Strategies Research Articles

New aspects of grassland recovery in old-fields revealed by trait-based analyses of perennial-crop-mediated succession.

Classical old‐field succession studies focused on vegetation changes after the abandonment of annual croplands or on succession after the elimination of cultivated crops. Perennial‐crop‐mediated succession, where fields are initially covered by perennial crops, reveals alternative aspects of old‐field succession theories. We tested the validity of classical theories of old‐field succession for perennial‐crop‐mediated succession. We formulated the following hypotheses: (1) functional diversity increases with increasing field age; (2) resource acquisition versus conservation trade‐off shifts toward conservation at community level during the succession; (3) the importance of spatial and temporal seed dispersal decreases during the succession; and (4) competitiveness and stress‐tolerance increases and ruderality decreases at community level during the succession. We studied functional diversity, trait distributions and plant strategies in differently aged old‐fields using chronosequence method. We found increasing functional richness and functional divergence, but also unchanged or decreasing functional evenness. We detected a shift from resource acquisition to resource conservation strategy of communities during the succession. The role of spatial and temporal seed dispersal was found to be important not only at the initial but also at latter successional stages. We found an increasing stress‐tolerance and a decreasing ruderality during succession, while the competitiveness remained unchanged at the community level. Despite the markedly different starting conditions, we found that classical and perennial‐crop‐mediated old‐field successions have some similarities regarding the changes of functional diversity, resource acquisition versus conservation trade‐off, and seed dispersal strategies. However, we revealed also the subsequent differences. The competitive character of communities remained stable during the succession; hence, the initial stages of perennial‐crop‐mediated succession can be similar to the middle stages of classical old‐field succession. Moreover, the occupied functional niche space and differentiation were larger in the older stages, but resources were not effectively utilized within this space, suggesting that the stabilization of the vegetation requires more time.

Inhabiting fauna in holdfasts of Lessonia nigrescens complex. Is it an indicator of ecological integrity in exploited kelp beds in northern Chile?

Lessonia nigrescens complex holdfasts habitats are home to a wide diversity of invertebrates. The holdfasts associated fauna is sensitive to the kelp fishery in northern Chile because one of the management recommendation is to harvest the whole plant. Considering the above, and the ecological role play by brown algae as foundation species, this study proposes the use of fauna inhabiting the holdfasts as an ecological indicator to monitor the integrity of exploited kelp beds. To accomplish this objective, the morphology of plants and holdfasts was evaluated together with the composition, abundance and community structure associated in three types of resource conservation strategies based on fishery management spatially explicit: open access areas and management areas (to harvest), and marine protected areas (with no harvest), in Atacama and Coquimbo (26-32°S). The results show that high harvest pressure on exploited kelp beds transforms the plant morphology and holdfast, altering the colonization process and species aggregation predicted for these biogenic habitats modifying the expected biodiversity. Thus, associated fauna in open access areas has lower species richness, abundance and biodiversity of organisms than their counterparts in management areas or marine protected areas. Moreover, the structure of the holdfast associated communities, are more variables in open access areas. The results suggest that holdfasts are representative micro-ecosystems of the intertidal environment, and can be used as sampling replicable and comparable units to monitor exploited kelp beds integrity in fisheries open access areas. This ecological indicator is easy to evaluate and disseminate among users of the kelp productive chain.

Trait values and not invasive status determine competitive outcomes between native and invasive species under varying soil nutrient availability

AbstractInvasion by exotic plants is often associated with nutrient enrichment of soils, particularly on soils of naturally low fertility. As a consequence, it is likely that the outcome of competitive interactions between native and invasive plants may be mediated by soil nutrient availability. We independently investigated competitive effect and response as well as the occurrence of asymmetric competition among native and invasive plants on soils of varying nutrient availability, using a glasshouse experiment. Seedlings of eight co‐occurring pairs of invasive and native species from low fertility Hawkesbury Sandstone‐derived soil were grown under low and high nutrient availability. We tested the hypotheses that native species would be competitively superior at low nutrient availability and have trait values associated with a resource conservation strategy while invasive species would be competitively superior at high nutrient availability and have trait values associated with a resource acquisition strategy. We found that nutrient availability did not mediate competitive interactions between invasive and native species. Instead, two invasive and one native species were always competitively superior irrespective of nutrient availability. Competitively superior species displayed a mixture of both resource conservation and acquisition strategies at low and high nutrient availability. In support of previous studies, we found that the a priori classification of invasive and native species does not predict competitive superiority at varying nutrient levels. Rather, species specific differences in trait values provide a competitive advantage in response to nutrient availability.

Robust fuzzy and multi-objective optimization approaches to generate alternate solutions for resource conservation of eco-industrial park involving various future events

Eco-industrial parks (EIPs), typically including industrial plants and companies, provide a promising resource conservation strategy that includes opportunities for material exchange between participating plants and minimizes the consumption of resources. However, when the participating plants in the EIP fail to share data, various possible future events are ought to happen in future. In this paper, we present various robust optimization approaches in order to generate alternate solutions for resource conservation in EIPs through water reuse networks that take various future events into consideration. Three different optimization approaches are discussed and solved in this study. In the first optimization approach, the objective function is set to minimize the overall emergy of the EIP. In the second approach, an emergy-based fuzzy optimization model is presented and the objective function of the model is to maximize the overall degree of satisfaction. Finally, a solution method incorporating the lexicographic optimization and augmented ɛ-constraint method is proposed in order to solve the multi-objective optimization (MOO) problem, which simultaneously minimizes the overall freshwater consumption and the regenerated water flow-rate. The resulting model is formulated as a mixed-integer linear programming problem taking into consideration two scenarios (EIP reuse network with a regenerator and direct reuse EIP network without a regenerator). The applicability of the proposed optimization approaches is demonstrated by comparison with a literature case study and by comparing the optimal resource conservation results for the two scenarios. The results show that a regeneration unit with a fixed outlet concentration into the base system causes a 15.6%, 9.8%, 21.2%, and 16.2% reduction in the overall emergy, TAC, freshwater, and wastewater, respectively, in comparison to that of direct reuse.

SYNERGY OF OPTICAL AND SAR DATA FOR MAPPING AND MONITORING MANGROVES

Quantitative information on mangrove cover extents is essential in producing relevant resource management plans and conservation strategies. In the Philippines, mangrove rehabilitation was made a priority in relation to disaster risk response and mitigation following the calamities in the coastal communities during typhoon Haiyan/Yolanda; hence, baseline information on the extent of remaining mangrove cover was essential for effective site interventions. Although mangrove cover maps for the country already exists, analysis of mangrove cover changes were limited to the application of fixed annual deforestation rates due to the challenge of acquiring consistent temporal cloud-free optical satellite data over large landscapes. This study presents an initial analysis of SAR and optical imagery combined with field-based observations for detecting mangrove cover extent and changes through a straightforward graphical approach. The analysis is part of a larger study evaluating the synergistic use of time-series L-band SAR and optical data for mapping and monitoring of mangroves. Image segmentation was implemented on the 25-meter ALOS/PALSAR image mosaics, in which the generated objects were subjected to statistical analysis using the software R. In combination with selected Landsat bands, the class statistics from the image bands were used to generate decision trees and thresholds for the hierarchical image classification. The results were compared with global mangrove cover dataset and validated using collected ground truth data. This study developed an integrated replicable approach for analyzing future radar and optical datasets, essential in national level mangrove cover change monitoring and assessment for long-term conservation targets and strategies.

SYNERGY OF OPTICAL AND SAR DATA FOR MAPPING AND MONITORING MANGROVES

Abstract. Quantitative information on mangrove cover extents is essential in producing relevant resource management plans and conservation strategies. In the Philippines, mangrove rehabilitation was made a priority in relation to disaster risk response and mitigation following the calamities in the coastal communities during typhoon Haiyan/Yolanda; hence, baseline information on the extent of remaining mangrove cover was essential for effective site interventions. Although mangrove cover maps for the country already exists, analysis of mangrove cover changes were limited to the application of fixed annual deforestation rates due to the challenge of acquiring consistent temporal cloud-free optical satellite data over large landscapes. This study presents an initial analysis of SAR and optical imagery combined with field-based observations for detecting mangrove cover extent and changes through a straightforward graphical approach. The analysis is part of a larger study evaluating the synergistic use of time-series L-band SAR and optical data for mapping and monitoring of mangroves. Image segmentation was implemented on the 25-meter ALOS/PALSAR image mosaics, in which the generated objects were subjected to statistical analysis using the software R. In combination with selected Landsat bands, the class statistics from the image bands were used to generate decision trees and thresholds for the hierarchical image classification. The results were compared with global mangrove cover dataset and validated using collected ground truth data. This study developed an integrated replicable approach for analyzing future radar and optical datasets, essential in national level mangrove cover change monitoring and assessment for long-term conservation targets and strategies.

Shifting targets: spatial priorities for ex situ plant conservation depend on interactions between current threats, climate change, and uncertainty

Few strategies for conservation seed banking consider current and climate threats simultaneously and few—if any—represent uncertainty inherent in the assessment process. Here we evaluate the vulnerability of 5148 populations of 71 rare plant species in the North American Central Highlands to current threat, threat from climate change, and their combination. We calculated priorities based on current threat using existing conservation status and protection, and priorities based on climate threat using ecological niche models and species-level traits related to reproduction and dispersal. Current- and climate-based priorities were integrated using a weighted average of rank priority. We managed uncertainty using either a precautionary strategy that avoids any extinctions or a resource-conservative strategy that directs attention to species known to be vulnerable with high certainty. Priorities based on current threats highlighted presently rare species while priorities based on climate threat emphasized presently common species. The location of geographic “hotspots” providing opportunities for efficient seed banking depended strongly on the weight of the climate module relative to the current module, the strategy used to handle uncertainty, and emissions scenario. Integrating threats highlighted some hotspots that were not identified using just current or climate threat, indicating the importance of considering current and climate threats simultaneously. Only the Central Basin of Tennessee, a known center of endemism, was consistently emphasized. We urge (1) integrating current and climate threats when designing seed-banking strategies; and (2) reporting of uncertainty in a manner that allows decision-makers to choose actions based on available resources and tolerable risk.

Local adaptation to temperature and precipitation in naturally fragmented populations of Cephalotaxus oliveri, an endangered conifer endemic to China.

Cephalotaxus oliveri is an endangered tertiary relict conifer endemic to China. The species survives in a wide range from west to east with heterogeneous climatic conditions. Precipitation and temperature are main restrictive factors for distribution of C. oliveri. In order to comprehend the mechanism of adaptive evolution to climate variation, we employed ISSR markers to detect adaptive evolution loci, to identify the association between variation in temperature and precipitation and adaptive loci, and to investigate the genetic structure for 22 C. oliveri natural populations. In total, 14 outlier loci were identified, of which five were associated with temperature and precipitation. Among outlier loci, linkage disequilibrium (LD) was high (42.86%), which also provided strong evidence for selection. In addition, C. oliveri possessed high genetic variation (93.31%) and population differentiation, which may provide raw material to evolution and accelerate local adaptation, respectively. Ecological niche modeling showed that global warming will cause a shift for populations of C. oliveri from south to north with a shrinkage of southern areas. Our results contribute to understand the potential response of conifers to climatic changes, and provide new insights for conifer resource management and conservation strategies.

Grassland root functional parameters vary according to a community‐level resource acquisition–conservation trade‐off

AbstractQuestionsThe fundamental trade‐off between fine root trait attributes related to resource acquisition and conservation is well documented at species and community levels. However, relations remain unclear between this trade‐off and community adaptation to environmental factors. As a result we ask: (1) how do fertility changes influence community position along the root acquisition–conservation trade‐off; (2) how does root position along the soil profile influence its functional parameter; and (3) do fertility and soil depth have an interactive effect on community root parameters?LocationNative multi‐species temperate grassland in the French Massif Central.MethodsWe assessed botanical composition and measured community root functional parameters (at plot and soil layer levels) in 16 plots differentiated by the amounts of N and P fertilizers applied over 16 yr and a soil depth gradient. Structural equation models were used to analyse relations among environmental factors, botanical composition and root functional parameters.ResultsBotanical composition and plot‐level root functional parameters vary according to fertility and soil depth. Communities from low fertility plots display a resource conservation strategy, i.e. high root tissue density, low specific root length (SRL) and low root length density (RLD), while communities from high fertility plots display a resource acquisition strategy, i.e. opposite parameter values. This demonstrates the importance of root resource management strategies in community adaptation to resource acquisition. Roots display different parameter values with soil depth. Roots in the surface horizon have small diameters and high SRL and RLD, suggesting intensive soil exploration and a high nutrient acquisition capacity. Roots in deep horizons have large diameters and low SRL, suggesting high water transport capacity per root length unit. This pattern is affected by plot fertility, i.e. communities from high fertility plots show higher root strategy differentiation with depth than communities from low fertility plots. We hypothesize that this root specialization along the soil profile enables species to be competitive for nutrient uptake in shallow soil layers and water uptake and transport in deep soil layers.ConclusionOur study provides evidence that fertility and soil depth modified root functional parameters, in agreement with predictions from the economics spectrum theory.

Absorptive roots trait plasticity explains the variation of root foraging strategies in Cunninghamia lanceolata

The architecture and morphology of absorptive roots show substantial plasticity in response to forest management practices. These traits are known to play important roles in the acquisition of soil resources by trees. However, the effects of nutrient addition, thinning and pruning on absorptive root traits and their feedback to root foraging strategies remain unclear.We investigated the values and plasticity of traits related to nutrient foraging (root architecture, growth and morphology) for first- and second-order roots (absorptive roots) following nitrogen (N) addition, phosphorous (P) addition, thinning and pruning treatments in a young Chinese fir (Cunninghamia lanceolata) plantation.We measured twelve traits of absorptive roots under the five treatments (control, N addition, P addition, thinning and pruning) and determined relationships between the values and plasticity of root traits and stem growth rate. We demonstrated clear patterns of root traits and their plasticity in response to the treatments. N and P addition increased root biomass (B) and root tissue density (RTD). Thinning and pruning led to larger specific root length (SRL) and root nitrogen concentrations (N), but resulted in lower root length (L) and root length density (RLD). Principal component analysis of the measured traits and plasticity provided evidence for two suites of traits related to resource acquisition and conservation strategies among treatments. The trait syndromes exhibiting resource acquisition strategy (SRL and N) is arrayed well along the positive part of the first axis, whereas the opposite trait syndromes with resource conservation strategy (root diameter and RTD) is along the negative part of the first axis. The first axis also separates nutrient-induced treatments (N and P addition) from light-mediated treatments (pruning and thinning). Furthermore, first-order root exhibited higher foraging sensitivity and precision (expressed as relative fine root length difference) in response to P addition than to the other treatments. The foraging sensitivity and precision, plus B, L and RLD showed that first-order roots are more responsive to environment than second-order roots across the treatments. Stem growth rate was correlated positively with absorptive root traits (biomass, root surface area index, root length density, and root tip number) after thinning, but negatively with these traits after N and P addition.These findings demonstrate that C. lanceolata finely tuned root foraging strategies between first- and second-order root traits and their plasticity at the intraspecific level in response to forest management practices. Further studies may explore nutrient-induced and light-mediated foraging strategies between absorptive roots across root branch orders in mature Chinese fir plantation.

Fine root tradeoffs between nitrogen concentration and xylem vessel traits preclude unified whole-plant resource strategies in Helianthus.

Recent work suggests variation in plant growth strategies is governed by a tradeoff in resource acquisition and use, ranging from a rapid resource acquisition strategy to a resource-conservative strategy. While evidence for this tradeoff has been found in leaves, knowledge of root trait strategies, and whether they reflect adaptive differentiation across environments, is limited. In the greenhouse, we investigated variation in fine root morphology (specific root length and tissue density), chemistry (nitrogen concentration and carbon:nitrogen), and anatomy (root cross-sectional traits) in populations of 26 Helianthus species and sister Phoebanthus tenuifolius. We also compared root trait variation in this study with leaf trait variation previously reported in a parallel study of these populations. Root traits varied widely and exhibited little phylogenetic signal, suggesting high evolutionary lability. Specific root length and root tissue density were weakly negatively correlated, but neither was associated with root nitrogen, providing little support for a single axis of root trait covariation. Correlations between traits measured in the greenhouse and native site characteristics were generally weak, suggesting a variety of equally viable root trait combinations exist within and across environments. However, high root nitrogen was associated with lower xylem vessel number and cross-sectional area, suggesting a tradeoff between nutrient investment and water transport capacity. This led to correlations between root and leaf traits that were not always consistent with an acquisition-conservation tradeoff at the whole-plant level. Given that roots must balance acquisition of water and nutrients with functions like anchorage, exudation, and microbial symbioses, the varied evidence for root trait covariation likely reflects the complexity of interacting selection pressures belowground. Similarly, the lack of evidence for a single acquisition-conservation tradeoff at the whole-plant level likely reflects the vastly different selection pressures shaping roots and leaves, and the resources they are optimized to obtain.

Distribution of functional traits in subtropical trees across environmental and forest use gradients

The relationship between functional traits and environmental factors contribute to understanding community structure and predicting which species will be able to elude environmental filters in different habitats. We selected 10 functional traits related to morphology, demography and regeneration niche in 54 subtropical premontane tree species to describe their main axes of functional differentiation. We derived species traits, environmental variables and species abundance data from 20 1-ha permanent plots established in a seasonal subtropical premontane forest in northwestern Argentina. We analyzed the relationship between species functional traits and environmental factors through RLQ and fourth-corner analyzes. We found an axis of structural differentiation that segregates understory from canopy species, and an axis of functional differentiation that segregates species that maximize resource acquisition from those that promote resource conservation. Environmental and forest use gradients operate hierarchically over subtropical premontane tree species influencing the distribution of demographic and morphological traits. The interaction between climatic and topographic factors influences the distribution of species functional traits at the regional scale. In addition, the history of forest use seems to operate at the landscape scale and explains the distribution of species traits reflecting a trade-off between resource acquisition and resource conservation strategies in secondary forests across different successional stages. Our results support the idea that functional traits may be used to analyze community structure and dynamics through niche differentiation and environmental filtering processes.

Disentangling the relative importance of species occurrence, abundance and intraspecific variability in community assembly: a trait‐based approach at the whole‐plant level in Mediterranean forests

Understanding which factors and rules govern the process of assembly in communities constitutes one of the main challenges of plant community ecology. The presence of certain functional strategies along broad environmental gradients can help to understand the patterns observed in community assembly and the filtering mechanisms that take place. We used a trait‐based approach, quantifying variations in aboveground (leaf and stem) and belowground (root) functional traits along environmental gradients in Mediterranean forest communities (south Spain). We proposed a new practical method to quantify the relative importance of species turnover (distinguishing between species occurrence and abundance) versus intraspecific variation, which allowed us to better understand the assemblage rules of these plant communities along environmental gradients. Our results showed that the functional structure of the studied plant communities was highly determined by soil environment. Results from our modelling approach based on maximum likelihood estimators showed a predominant influence of soil water storage on most of the community functional traits. We found that changes in community functional structure along environmental gradients were mainly promoted by species turnover rather than by intraspecific variability. Specifically, our new method of variance decomposition demonstrated that between‐site trait variation was the result of changes in species occurrence rather than in the abundance of certain dominant species. In conclusion, this study showed that water availability promoted the predominance of specific trait values (both in above and belowground fractions) associated to a resource acquisition or conservation strategy. In addition, we provided evidence that changes on community functional structure along the environmental gradient were mainly promoted by a process of species replacement, which represent a crucial step towards a more general understanding of the relative importance of intraspecific versus interspecific trait variation in these woody Mediterranean communities.

Resource conservation strategies for rice‐wheat cropping systems on partially reclaimed sodic soils of the Indo‐Gangetic region, and their effects on soil carbon

AbstractThe Indo‐Gangetic plain is characterized by intensive agriculture, largely by resource‐poor small and marginal farmers. Vast swathes of salt‐affected areas in the region provide both challenges and opportunities to bolster food security and sequester carbon after reclamation. Sustainable management of reclaimed soils via resource conservation strategies, such as residue retention, is key to the prosperity of the farmer, as well as increases the efficiency of expensive initiatives to further reclaim sodic land areas, which currently lay barren. After five years of experimentation on resource conservation strategies for rice‐wheat systems on partially reclaimed sodic soils of the Indo‐Gangetic region, we evaluated changes in different soil carbon pools and crop yield. Out of all resource conservation techniques which were tested, rice‐wheat crop residue addition (30% of total production) was most effective in increasing soil organic carbon (SOC). In rice, without crop residue addition (WCR), soils under zero‐tillage with transplanting, summer ploughing with transplanting and direct seeding with brown manuring showed a significant increase in SOC over the control (puddling in rice, conventional tillage in wheat). In these treatments relatively higher levels of carbon were attained in all aggregate fractions compared to the control. Soil aggregate sizes in meso (0.25‐2.0 mm) and macro (2‐8 mm) ranges increased, whereas micro (< 0.25 mm) fractions decreased in soils under zero‐till practices, both with and without crop residue addition. Direct seeding with brown manuring and zero tillage with transplanting also showed an increase of 135% and 95%, respectively, over the control in microbial biomass carbon, without crop residue incorporation. In zero tillage with transplanting treatment, both with and without crop residue showed significant increase in soil carbon sequestration potential. Though the changes in accrued soil carbon did not bring about significant differences in terms of grain yield, overall synthesis in terms of balance between yield and carbon sequestration indicated that summer ploughing with transplanting and zero tillage with transplanting sequestered significantly higher rates of carbon, yet yielded on par with conventional practices. These could be appropriate alternatives to immediately replace conventional tillage and planting practices for rice‐wheat cropping systems in the sodic soils of the Indo‐Gangetic region.

Community implementation dynamics: Nutrient management in the New York City and Chesapeake Bay Watersheds

The creation of natural resource management and conservation strategies can be affected by engagement with local citizens and competing interests between agencies and stakeholders at the varying levels of governance. This paper examines the role of local engagement and the interaction between governance levels on the outcomes of nutrient management policy, a specific area of natural resource conservation and management. Presented are two case studies of the New York City and Chesapeake Bay Watersheds in the US. These case studies touch upon the themes of local citizen engagement and governance stakeholder interaction in changing nutrient management to improve water quality. An analysis of these cases leads to several key considerations for the creation and implementation of nutrient management and natural resource management more broadly, including the importance of: local citizen engagement, government brokering and cost sharing; and the need of all stakeholders to respect each other in the policy creation and implementation process.

The Strategy of Water Resources Conservation in Regunung Village, Tengaran Subdistrict, Semarang District

Title : The Strategy of Water Resources Conservation in Regunung Village, Tengaran Subdistrict, Semarang District. Water resource conservation is a required activity to do in in Regunung Village, Tengaran Subdistrict, Semarang District because this area is potentially dried and has often experienced the lack of clean water even though the water resource conservation is vegetatively conducted. The resecarh is conducted from June to August 2014. The purpose of this research is to analyze the strategy of water resource conservation in Regunung Village by analyze the social-economy condition and physical condition. The method used to gain data is obeservation and direct measuring including vegetation analysis, the data analysis of the citra condition of the changing of the land; the crossed tabulation analysis and Marcov Chain for the projection of the cahinging of the land use; the technique of interview using questioners to know the participation of community; the secondary data analysis, FGD to determine the strategy of water resource conservation with SWOT analysis. The population of this research is the people of Regunung Village. Respondent is purposively determined by the number of respondent based on Slovin formula, while the FGD informant is purposively determined. The result of the research shows that the condition of Regunung Village is located at discharged area CAT Salatiga with the various level of elevation and the type of soil is latosol. The changing of the use of land happening since 1991 - 2014. The vegetation condition shows that the planting method used in Regunung Village is Agroforestry. The index of diversity for three in Regunung Village is at the low level (0,8). The result of the social-economy condition research shows that the majority people's income is less than Rp. 1.000.000,00 and the level of participation is on placation level. The Water Resource Conservation Strategy suggested is the diversification strategy

Trait distribution patterns in savanna and forest plant assemblages and their relationship with soil features

Community ecologists seek to understand the processes acting on community assembly and the importance of species ecological differences to the co-existence of organisms. Here we investigated trait distribution patterns in two contrasting vegetation types, how the inclusion of intraspecific variability improves our ability to understand trait-based assembly, and if soil features predict the occurrence of non-random trait distribution patterns. We conducted our study at Emas National Park, Goias, Brazil. We used a null model approach to investigate trait distribution patterns and a model selection approach to quantify soil features important in structuring assemblages. In savanna, we detected trait convergence at individual and species level (evidence of environmental filters) favoring plants with resource conservation strategies. In forests, however, trait dispersion at individual level equal to a random expectation corroborated a premise of neutral theory (individuals ecological equivalence). Nevertheless, at species level, we found convergence (seed mass) and divergence (height), reflecting distinct strategies related to light capture and resource use. Therefore, including intraspecific trait variability did not improve the detection of non-random trait distribution patterns. Furthermore, the influence of soil features on trait patterns was different between savanna and forest. There was a tendency for niche differentiation toward more fertile and clayey soils, but the relative importance of soil factors in assembling communities could not be generalized for savannas and dry forests.

Sustainable livelihoods through conservation of wetland resources: a case of economic benefits from Ghodaghodi Lake, western Nepal

We investigated the participation of local ethnic groups in wetland conservation, determined the economic benefits that they received from the wetlands, and assessed socioeconomic factors that affect dependency on wetlands. A total of 217 wetland resource-user households residing around Ghodaghodi Lake, western Nepal were surveyed. Data were analyzed using descriptive statistics, t-tests and ordinary least squares regressions. The wetland resources contributed significantly to the household economy of the local people. Each household extracted lake resources at an annual worth of NPR 4379 ($63 USD), equivalent to 12.4% of the household total gross income. Although the people maintained a positive attitude toward wetland conservation, their participation in conservation efforts was inadequate. Socioeconomic factors such as larger household size, older age of the head of the family, and larger area of agricultural land increased the rate of resource extraction. In contrast, when households were involved with local conservation organizations, resource extraction was reduced. We recommend the following resource conservation and livelihood strategies: implementation of community-based conservation approaches to increase system productivity, adoption of biogas plants, and improved cooking stoves to reduce fuelwood consumption, coupled with conservation awareness programs.

Intraspecific leaf economic trait variation partially explains coffee performance across agroforestry management regimes

The leaf economics spectrum (LES) refers to a suite of correlated leaf-level physiological, morphological, and chemical traits that can be used to describe life-history strategy among plant species. Documenting LES trait variation across environmental gradients has been important for understanding natural plant community dynamics in response to environmental change. However few studies have examined how LES traits covary within crops, or how the LES is correlated with farm-level management practices or goals, especially for important tree-crops such as coffee. We analyzed within-species variation in eight leaf traits in 60 Coffea arabica plants, across four management treatments differing in shade-tree species composition, to test (i) if hypothesized LES patterns also describe within-species trait variation, and (ii) if LES traits vary in response to management regimes, or are correlated with reproductive output. Leaf traits varied widely across coffee plants with photosynthetic rates (Amass) and leaf area showing especially high variation. In bivariate and multivariate analyses, coffee leaf traits covaried in patterns consistent with the LES, suggesting shifts between leaf-level resource acquisition and conservation traits among plants may also underpin coffee responses to agroforestry management. The position of a coffee plant along the LES (as described by a principal component analysis score) was best explained by light availability, but did not vary systematically with shade tree composition. LES traits were weakly but significantly related to plant-level reproductive output: coffee plants associated with lower Amass and leaf N values, and higher leaf mass per area were associated with greater reproductive output. In showing that the LES describes resource capture and/or conservation strategies among coffee plants, our study represents a novel adoption of the LES to address applied questions in managed systems. Since within species differences in leaf traits partially explain differences in coffee yield, we also suggest that trait-based research in agroecology can contribute to an applied and comprehensive understanding of crop functional biology, and ultimately, agroecosystem structure and function.

Stress tolerance and ecophysiological ability of an invader and a native species in a seasonally dry tropical forest.

Ecophysiological traits of Prosopis juliflora (Sw.) DC. and a phylogenetically and ecologically similar native species, Anadenanthera colubrina (Vell.) Brenan, were studied to understand the invasive species’ success in caatinga, a seasonally dry tropical forest ecosystem of the Brazilian Northeast. To determine if the invader exhibited a superior resource-capture or a resource-conservative strategy, we measured biophysical and biochemical parameters in both species during dry and wet months over the course of two years. The results show that P. juliflora benefits from a flexible strategy in which it frequently outperforms the native species in resource capture traits under favorable conditions (e.g., photosynthesis), while also showing better stress tolerance (e.g., antioxidant activity) and water-use efficiency in unfavorable conditions. In addition, across both seasons the invasive has the advantage over the native with higher chlorophyll/carotenoids and chlorophyll a/b ratios, percent N, and leaf protein. We conclude that Prosopis juliflora utilizes light, water and nutrients more efficiently than Anadenanthera colubrina, and suffers lower intensity oxidative stress in environments with reduced water availability and high light radiation.