Acta Oecologica-International Journal of Ecology最新文献

Anthropogenic climate change has been identified as one of the main threats to current biodiversity, particularly for mountain species, which are especially sensitive to reductions of suitable habitat. Climate change impact assessments through correlative models have become a widely used tool for evaluating vulnerability of species to global warming. However, interpreting these results in an evolutionary context is essential to understand the phylogenetic structure of the predicted impact, as well as the potential evolutionary responses. The present study evaluates the impact of climate change on the Andean-Patagonian genus Onuris, interpreting the effect on its species and main phylogenetic groups. We first estimated a species phylogeny using both nuclear ribosomal and plastid data, which was then used to interpret the evolution of climatic niches and characterize the vulnerability of different species, evolutionary significant units (ESUs), and main lineages to climate change. Evaluations were conducted at the species level using species-specific metrics and at the genus level with emergent metrics such as richness, phylogenetic diversity, and shared response to local extirpation. Analyses showed that closely related species exhibit greater climatic niche similarity, suggesting a possible pattern of phylogenetic niche conservatism for divergence in the genus, with the greatest niche divergence recovered between lineages distributed in central-northern and southern Andean-Patagonian region. Species and ESUs of the lineage distributed in the southernmost portion of Patagonia (ca. 47°S–55°S) were most negatively affected under the different scenarios and models tested. The results also indicated a greater impact on richness than on phylogenetic diversity, mainly due to the establishment of the northern lineage in future projections over the range of the southern lineage. However, predictions show a pronounced negative effect of climate change for the entire genus. Likewise, results obtained suggest the high vulnerability of the current biota in the southern end of the Andean-Patagonian region.

Insect pollinators are declining worldwide due to many challenges and several approaches have been implemented to mitigate their loss. Farming with Alternative Pollinators (FAP) uses marketable habitat enhancement plants (MHEP) that yield substantial benefits for farmers from the first year. Studies with small-scale farmers have shown that FAP sustains high diversity and abundance of flower visitors and natural enemies, resulting in significant increases in smallholders' incomes, on average 121% higher. For the first time, we analyzed this approach in large-scale fields. Trials were conducted in 16 farms in two regions of Morocco, Sidi Slimane and Ksar El-Kebir, in 2021. We used melon (Cucumis melo) as the main crop and coriander, anise and sunflower as MHEP and selected in each farm 1 ha as trial area in larger monocultures. We compared FAP and control fields regarding abundance and richness of flower visitors, natural enemies and pests as well as net income of the whole field (1 ha). Flower visitors and natural enemies were significantly more diverse and abundant in FAP fields and there were also fewer pests. Our economic results show 17% higher net income per ha in FAP fields versus control fields in the Ksar El-Kebir region, and 12% higher net income in FAP fields compared to control fields in Sidi Slimane region. Although the mean yield difference was statistically significant, the income difference was not. We suggest more FAP trials are needed in different large-scale fields systems.

Water scarcity in arid and semi-arid regions affects ecosystem development. Therefore, elucidation of the mechanisms by which plant species in a given region respond to drought conditions may allow us to improve global vegetation. Encelia species are drought-tolerant and an important component of shrub communities in the arid and semi-arid regions of southern California, U.S.A.; these species are widely used for vegetation restoration in the region. This study aimed to investigate the morphological, and physiological responses in E. farinosa in relation to changes in soil properties under drought conditions. Plants were subjected to two levels of soil water regimes, drought and well-watered conditions (5% and 12% of gravimetric water content, respectively). After 3 months, above-ground biomass, basal diameter, leaf area, leaf and root relative water content, and root length were measured. The shoot:root ratio in dry mass and specific leaf area (SLA) were calculated. We also analyzed leaf and soil nutrients, including total C, N, and available P. In the drought treatment, E. farinosa showed significantly lower above-ground biomass, stem diameter, and shoot and root relative water content. Also, the drought treatment resulted in significantly lower leaf areas, while the SLA and root length were significantly higher. Leaf total C and N were higher in the drought treatment while leaf P was not affected by soil water content. The reduction in plant leaf area, root elongation and the increase in SLA under drought are known as drought avoidance strategies of plants, suggesting that E. farinosa hampers water loss by morphological regulations. Additionally, higher leaf content of C and N seems to be important for metabolic drought adaptation. Further research on osmotic adjustment and antioxidant defense systems will clarify the detailed drought tolerance mechanisms of E. farinosa in relation to C and N accumulation under drought conditions.

Scripus mariqueter is a native endangered plant species with both sexual and asexual reproduction in a coastal salt marsh wetland, eastern China. Understanding the patterns of growth and reproduction of S. mariqueter populations in different tidal flats and the main driving factors is necessary and urgent for the effective restoration of this species. The characteristics of growth and reproduction of S. mariqueter populations were investigated in the seaward, middle and landward habitats along the north, east and south directions of the Dongtan salt marsh wetland. Results showed that when individually and comprehensively analyzing the effect of soil physicochemical properties on the differentiation patterns of the growth and reproduction, based on the pairwise index analysis, SEM (structural equation model) and PCA (principal component analysis), soil salinity was the most important driving factor, and comprehensive factor (Y) played a major role than tidal levels and directions. Soil physicochemical factors independently explained 61.63% of the growth-reproduction variation, in which soil salinity explained 13.78% and the comprehensive factor explained 69.20%. Correlation between sexual and asexual reproduction was negative in series habitats in the north direction, and positive in series habitats in the east and south direction, where soil physicochemical properties in the series habitats in the south direction was relatively unfavorable or stressful than those in the east and north direction in term of sexual reproduction. Our results provided a theoretical and practical basis for the sustainable conservation and restoration of S. mariqueter population, which may further help enhance its ecological functions in protecting beaches, reducing waves, facilitating siltation and maintaining biodiversity in the coastal salt marsh wetland, eastern China.

The decline in species diversity within nutrient-enriched grasslands is commonly explained by a single hypothesis that often overlooks the potential interconnected roles of soil nutrients, light, and plant productivity. In a 2-year field experiment involving multiple nutrient additions (nitrogen, phosphorus, and potassium; NPK) conducted in an alpine meadow on the eastern Qinghai-Tibet Plateau, we investigated the simultaneous impact of three driving factors (soil nutrients, litter, and light) on species loss. Our findings show that the reduction in species richness can be attributed to belowground soil nutrient enrichment and aboveground light asymmetry. Specifically, the increase in soil nutrients following NPK addition directly contributed to the decline in species richness. Light limitation associated with an increase in the aboveground net primary productivity (ANPP) indirectly accelerates competitive exclusion, leading to species loss. The increased ANPP was primarily influenced by the greater proportion of the grass species Elymus nutans in the NPK-fertilized plots, highlighting the significant role of dominant species in restricting light availability.

Contrary to expectations, our results did not support the negative impact of litter on species richness. In summary, our findings indicate that interspecies competition for soil nutrients and light availability are the two primary drivers of species loss in alpine meadow communities. This insight has crucial implications for understanding the effects of nutrient enrichment on biodiversity, ecosystem functioning, and services in alpine meadows on the Qinghai-Tibet Plateau.

Arid and semiarid ecosystems display several environmental filters naturally restricting plant community composition. Such filters become more severe after some disturbance and may thus hamper the survival of young plants. The role of remnant trees in succession needs to be better understood to identify patterns and functional traits that might facilitate natural regeneration in drylands. This study evaluated the role of remnant trees in the succession process in the caatinga vegetation (Brazilian seasonally dry tropical forest), testing the effect of a typical tree, the juazeiro (Ziziphus joazeiro Mart.) in richness and abundance of seedlings in areas of abandoned pasture, in Northeastern Brazil. A perimeter was outlined around each plant (n = 20) with a diameter equivalent to each tree crown; all seedlings of woody species up to 0.5 m in height, within that perimeter, were collected and identified. Control areas with the same dimensions were delimited in adjacent locations (n = 20) without the influence of remnant trees, followed by the same data surveys. Mean species richness was of 7.8 ± 4.8 under the juazeiro canopies, compared to 2.3 ± 1.9 in the control areas. Species abundance was also greater under the presence of Z. joazeiro, with an average of 16.9 ± 4.8, against 4.1 ± 4.2 individuals in the controls. Among the abiotic factors evaluated, it is suggested that soil and air temperatures may show a greater influence on the recruitment of seedlings, benefiting natural regeneration under Z. joazeiro. Z. joazeiro ramnant trees appear to facilitate the natural regeneration of tropical drylands. We suggest considering the use of these plants as catalysts for the nucleation process in the restoration of the caatinga.

The management of plants and landscapes can affect the reproductive cycle of species through changes in morphology, temporal distribution of resources, and productivity, with ecological implications. In this study, we investigated the influence of management practices on the reproductive phenology and nectar availability of Cereus jamacaru DC, a columnar cactus native to Brazil managed by local people in the Caatinga dry forest. Our results reveal that the traditional management practices alter the quantitative and spatiotemporal distribution of resources (flowers, fruits, and nectar) of individuals of C. jamacaru in the studied Caatinga. All populations exhibited annual patterns of flowering and fruiting. However, individuals of the ex situ managed population showed a distinct temporal distribution pattern of flowering, with flower buds and flowers more regularly distributed throughout the reproductive period, compared to individuals of the in situ and unmanaged populations. Management practices differentially affected the production of flower buds, flowers, and fruits with a positive effect on fruit set in the in situ managed population. In addition, individuals of managed populations presented anticipation in the average date of the emission peaks of flower buds and ripe fruits. Individuals from the in situ managed population had available a greater volume of nectar with a higher sugar concentration per flower (twice as high) compared to the ex situ managed population and unmanaged population. The management practices seem to provide advantageous conditions for individuals of C. jamacaru since they allow higher availability of resources (flowers, nectar, and fruits) for a longer period in the Caatinga dry forest. Thus, management practices can prolong the temporal distribution of flowers and fruits, providing more resources for specialized pollinators (Sphingids) and dispersers (birds, reptiles), which are groups vulnerable to anthropic disturbances and climate changes in the Caatinga dry forest. These practices ultimately contribute to the maintenance of key ecological interactions of other species dependent on these vectors, benefiting the whole plant and animal community in the Caatinga dry forest.

In some species, females vary in the numbers of times they mate. While polyandry will always be beneficial to a male that mate with a previously mated female, the effect on female fitness is unclear. From females' perspective, variation in matedness can reflect adaptive differences in females’ requirements for mating or non-adaptive chance factors. Pollinating fig wasps have been considered to be mostly monandrous although polyandry has been confirmed in a number of species. Here we first show that the pollinating fig wasp, Platyscapa awekei, is polyandrous. Second, we show that intraspecific variation in female matedness may be explained best by chance encounters between males and receptive females. The mean number of offspring does not increase with polyandry. Nor is there evidence of sperm limitation. These observations rule out direct benefits to females. Despite evidence for multiply-mated females having mated with less compatible males, multiple mating is not combined with selective preference for more compatible males' sperm, ruling out indirect benefits. Therefore variation in female matedness seems to have no fitness benefit to females and from the females' perspective may be best explained by chance variation in encounter rates between males and receptive females.

Enhanced mammal functional diversity is crucial for forest ecological functioning. However, this group is affected by habitat degradation, such as mineral exploitation, which is a major threat worldwide. In these habitats, the maintenance of forest patches is important to support species diversity. Here, we addressed this knowledge gap by examining the functional diversity of medium-sized mammals among forest patches of different sizes in an area of approximately 3195 ha that is used for copper mining in the eastern Pará state, in the eastern Brazilian Amazon. In these patches, we also observed responses between mammal functional diversity and patch structural complexity. We used camera traps to survey the mammal fauna. We observed that large forest patches are associated with enhanced mammal functional diversity, mainly due to higher canopy closure and overstory tree density. In these habitats, species with functional attributes that allow resource partitioning may occur, which is important for habitat functioning. These findings have major implications for maintaining forest patch heterogeneity in mined areas, which is important for mammal functional diversity. Thus, management efforts in mining areas should explicitly include large forest patches to conserve mammal assemblages.

Slash-and-burn agriculture is a common practice in dry forests worldwide. Understanding the relative importance of different regeneration mechanisms following this disturbance provides insights into forest regeneration dynamics and resilience. We assessed differences in structural components, the relative contribution of vegetative and sexual reproduction, and the taxonomic composition of woody assemblages among different habitats in a Brazilian Caatinga dry forest after slash-and-burn agriculture. We assessed vegetation parameters (i.e., basal area, height, species richness, and the frequency of each regeneration mechanism) in recently abandoned fields, regenerating forest stands and old-growth forest stands. Overall, trees originates from root suckers accounted for at least 40% of the individuals, stems, and basal areas across the habitats. The structure of regenerating stands was similar to old-growth stands except for species composition, total number of roots, and number of primary roots. The aboveground basal area varied in total values, but not averages, among habitats, indicating a rapid recovery of aboveground biomass after slash-and-burn agriculture. Conversely, recently abandoned fields had higher belowground basal area and basal area of primary roots, revealing that the trees in these habitats emit more roots even with fewer individuals. There was a high degree of species turnover among the habitats, probably due to both species selection by farmers and environmental effects. Nevertheless, the dominant species presented both regeneration mechanisms across the habitats. Our findings thus show that the Caatinga dry forest regeneration considerably relies on the ability of woody plant species to emit root suckers in addition to sexual reproduction, which should be considered for better management practices as slash-and-burn agriculture is and will continue to be practiced.