Biotic component

About: Biotic component is a research topic. Over the lifetime, 1478 publications have been published within this topic receiving 50177 citations.

The Hidden World within Plants: Ecological and Evolutionary Considerations for Defining Functioning of Microbial Endophytes

Abstract: All plants are inhabited internally by diverse microbial communities comprising bacterial, archaeal, fungal, and protistic taxa. These microorganisms showing endophytic lifestyles play crucial roles in plant development, growth, fitness, and diversification. The increasing awareness of and information on endophytes provide insight into the complexity of the plant microbiome. The nature of plant-endophyte interactions ranges from mutualism to pathogenicity. This depends on a set of abiotic and biotic factors, including the genotypes of plants and microbes, environmental conditions, and the dynamic network of interactions within the plant biome. In this review, we address the concept of endophytism, considering the latest insights into evolution, plant ecosystem functioning, and multipartite interactions.

Hidden treatments in ecological experiments: re-evaluating the ecosystem function of biodiversity.

Abstract: Interactions between biotic and abiotic pro- cesses complicate the design and interpretation of eco- logical experiments. Separating causality from simple correlation requires distinguishing among experimental treatments, experimental responses, and the many pro- cesses and properties that are correlated with either the treatments or the responses, or both. When an experi- mental manipulation has multiple components, but only one of them is identified as the experimental treatment, erroneous conclusions about cause and eAect relation- ships are likely because the actual cause of any observed response may be ignored in the interpretation of the experimental results. This unrecognized cause of an observed response can be considered a ''hidden treat- ment.'' Three types of hidden treatments are potential problems in biodiversity experiments: (1) abiotic condi- tions, such as resource levels, or biotic conditions, such as predation, which are intentionally or unintentionally altered in order to create diAerences in species numbers for ''diversity'' treatments; (2) non-random selection of species with particular attributes that produce treatment diAerences that exceed those due to ''diversity'' alone; and (3) the increased statistical probability of including a species with a dominant negative or positive eAect (e.g., dense shade, or nitrogen fixation) in randomly selected groups of species of increasing number or ''diversity.'' In each of these cases, treatment responses that are actually the result of the ''hidden treatment'' may be inadver- tently attributed to variation in species diversity. Case studies re-evaluating three diAerent types of biodiversity experiments demonstrate that the increases found in such ecosystem properties as productivity, nutrient use eAciency, and stability (all of which were attributed to higher levels of species diversity) were actually caused by ''hidden treatments'' that altered plant biomass and productivity.

Alternative states and positive feedbacks in restoration ecology

Abstract: There is increasing interest in developing better predictive tools and a broader conceptual framework to guide the restoration of degraded land. Traditionally, restoration efforts have focused on re-establishing historical disturbance regimes or abiotic conditions, relying on successional processes to guide the recovery of biotic communities. However, strong feedbacks between biotic factors and the physical environment can alter the efficacy of these successional-based management efforts. Recent experimental work indicates that some degraded systems are resilient to traditional restoration efforts owing to constraints such as changes in landscape connectivity and organization, loss of native species pools, shifts in species dominance, trophic interactions and/or invasion by exotics, and concomitant effects on biogeochemical processes. Models of alternative ecosystem states that incorporate system thresholds and feedbacks are now being applied to the dynamics of recovery in degraded systems and are suggesting ways in which restoration can identify, prioritize and address these constraints.

The Phenology of Tropical Forests: Adaptive Significance and Consequences for Primary Consumers*

Abstract: Most tropical woody plants produce new leaves and flowers in bursts rather than continuously, and most tropical forest communities display seasonal variation in the presence of new leaves, flowers, and fruits. This patterning suggests that phenological changes represent adaptations to either biotic or abiotic factors. Biotic factors may select for either a staggering or a clustering of the phenological activity of individual plant species. We review the evidence for several hypotheses. The idea that plant species can reduce predation by synchronizing their phenological activity has the best support. However, because biotic factors are often arbitrary with respect to the timing of these peaks, it is essential also to consider abiotic influences. A review of published studies demonstrates a major role for climate. Peaks in irradiance are accompanied by peaks in flushing and flowering except where water stress makes this impossible. Thus, in seasonally dry forests, many plants concentrate leafing and flowering around the start of the rainy season; they also tend to fruit at the same time, probably to minimize seedling mortality during the subsequent dry season. Phenological variation at the level of the forest community affects primary consumers who respond by dietary switching, seasonal breeding, changes in range use, or migration. During periods of scarcity, certain plant products, keystone resources, act as mainstays of the primary consumer community.

Is There a Latitudinal Gradient in the Importance of Biotic Interactions

Abstract: Biotic interactions are believed to play a role in the origin and maintenance of species diversity, and multiple hypotheses link the latitudinal diversity gradient to a presumed gradient in the importance of biotic interactions. Here we address whether biotic interactions are more important at low latitudes, finding support for this hypothesis from a wide range of interactions. Some of the best-supported examples are higher herbivory and insect predation in the tropics, and predominantly tropical mutualisms such as cleaning symbioses and ant-plant interactions. For studies that included tropical regions, biotic interactions were never more important at high latitudes. Although our results support the hypothesis that biotic interactions are more important in the tropics, additional research is needed, including latitudinal comparisons of rates of molecular evolution for genes involved in biotic interactions, estimates of gradients in interaction strength, and phylogenetic comparisons of the traits that med...