The Who or the How? Species vs. Ecosystem Function Priorities in Conservation Ecology

Shifting the paradigm: The role of introduced plants in the resiliency of terrestrial ecosystems to climate change

Current ecological communities are in a constant state of flux from climate change and from species introductions. Recent discussion has focused on the positive roles introduced species can play in ecological communities and on the importance of conserving resilient ecosystems, but not how these two ideas intersect. There has been insufficient work to define the attributes needed to support ecosystem resilience to climate change in modern communities. Here, I argue that non-invasive, introduced plant species could play an important role in supporting the resilience of terrestrial ecosystems to climate change. Using examples from multiple taxonomic groups and ecosystems, I discuss how introduced plants can contribute to ecosystem resilience via their roles in plant and insect communities, as well as their associated ecosystem functions. I highlight the current and potential contributions of introduced plants and where there are critical knowledge gaps. Determining when and how introduced plants are contributing to the resilience of ecosystems to climate change will contribute to effective conservation strategies.

Improving ecosystem health in highly altered river basins: a generalized framework and its application to the Mississippi-Atchafalaya River Basin

Continued large-scale public investment in declining ecosystems depends on demonstrations of "success". While the public conception of "success" often focuses on restoration to a pre-disturbance condition, the scientific community is more likely to measure success in terms of improved ecosystem health. Using a combination of literature review, workshops and expert solicitation we propose a generalized framework to improve ecosystem health in highly altered river basins by reducing ecosystem stressors, enhancing ecosystem processes and increasing ecosystem resilience. We illustrate the use of this framework in the Mississippi-Atchafalaya River Basin (MARB) of the central United States (U.S.), by (i) identifying key stressors related to human activities, and (ii) creating a conceptual ecosystem model relating those stressors to effects on ecosystem structure and processes. As a result of our analysis, we identify a set of landscape-level indicators of ecosystem health, emphasizing leading indicators of stressor removal (e.g., reduced anthropogenic nutrient inputs), increased ecosystem function (e.g., increased water storage in the landscape) and increased resilience (e.g., changes in the percentage of perennial vegetative cover). We suggest that by including these indicators, along with lagging indicators such as direct measurements of water quality, stakeholders will be better able to assess the effectiveness of management actions. For example, if both leading and lagging indicators show improvement over time, then management actions are on track to attain desired ecosystem condition. If, however, leading indicators are not improving or even declining, then fundamental challenges to ecosystem health remain to be addressed and failure to address these will ultimately lead to declines in lagging indicators such as water quality. Although our model and indicators are specific to the MARB, we believe that the generalized framework and the process of model and indicator development will be valuable in an array of altered river basins.

Do ecosystems have functions?

'Ecosystem function' and 'ecosystem functioning' became core keywords in the ecological literature on ecosystems, their structure, development and integrity. We investigate functions from the perspective of causal contributions to higher capacities, as selected effects, as contributions to the stability and self-maintenance of organisms and as type-fixed effects. Based on an in-depth discourse in philosophy of science, we conclude that ecosystems do not have functions in any sense that goes beyond a mere description of a causal contribution. We recommend the terms 'ecosystem function' and 'ecosystem functioning' be avoided in the ecological literature (and beyond).

Calling time on alien plantscapes

Both urban and rural environments around the globe have become dominated by alien plant species to the extent that plantscapes from one region or country have become difficult to distinguish from many others. This process of plant community homogenisation comes at a cost to cultural identity and undermines people's sense of place. Although invasive alien plant species have received considerable attention in recent decades, issues with non-invasive alien plant species have largely been ignored, and yet they contribute significantly to biotic homogeneity and impose an ever accumulating invasion debt: a debt that increases in proportion with their population sizes. By contrast, an abundance of native species in the places where people live is important for strengthening commitment to biodiversity conservation. Is there therefore sufficient evidence of harm from increasing numbers of non-invasive alien plants to justify local and central governments introducing measures to substantially reduce the proportion of non-invasive aliens in both urban and rural environments?

Biodiversity: the overlooked source of human health

Biodiversity is the measure of the variation of lifeforms in a given ecological system. Biodiversity provides ecosystems with the robustness, stability, and resilience that sustains them. This is ultimately essential for our survival because we depend on the services that natural ecosystems provide (food, fresh water, air, climate, and medicine). Despite this, human activity is driving an unprecedented rate of biodiversity decline, which may jeopardize the life-support systems of the planet if no urgent action is taken. In this article we show why biodiversity is essential for human health. We raise our case and focus on the biomedicine services that are enabled by biodiversity, and we present known and novel approaches to promote biodiversity conservation.

Cell types as species: Exploring a metaphor

The concept of "cell type," though fundamental to cell biology, is controversial. Cells have historically been classified into types based on morphology, physiology, or location. More recently, single cell transcriptomic studies have revealed fine-scale differences among cells with similar gross phenotypes. Transcriptomic snapshots of cells at various stages of differentiation, and of cells under different physiological conditions, have shown that in many cases variation is more continuous than discrete, raising questions about the relationship between cell type and cell state. Some researchers have rejected the notion of fixed types altogether. Throughout the history of discussions on cell type, cell biologists have compared the problem of defining cell type with the interminable and often contentious debate over the definition of arguably the most important concept in systematics and evolutionary biology, "species." In the last decades, systematics, like cell biology, has been transformed by the increasing availability of molecular data, and the fine-grained resolution of genetic relationships have generated new ideas about how that variation should be classified. There are numerous parallels between the two fields that make exploration of the "cell types as species" metaphor timely. These parallels begin with philosophy, with discussion of both cell types and species as being either individuals, groups, or something in between (e.g., homeostatic property clusters). In each field there are various different types of lineages that form trees or networks that can (and in some cases do) provide criteria for grouping. Developing and refining models for evolutionary divergence of species and for cell type differentiation are parallel goals of the two fields. The goal of this essay is to highlight such parallels with the hope of inspiring biologists in both fields to look for new solutions to similar problems outside of their own field.

Ecosystem services provided by the exotic bivalves Dreissena polymorpha, D. rostriformis bugensis, and Limnoperna fortunei

The ecosystem services approach to conservation is becoming central to environmental policy decision making. While many negative biological invasion-driven impacts on ecosystem structure and functioning have been identified, much less was done to evaluate their ecosystem services. In this paper, we focus on the often-overlooked ecosystem services provided by three notable exotic ecosystem engineering bivalves, the zebra mussel, the quagga mussel, and the golden mussel. One of the most significant benefits of invasive bivalves is water filtration, which results in water purification and changes rates of nutrient cycling, thus mitigating the effects of eutrophication. Mussels are widely used as sentinel organisms for the assessment and biomonitoring of contaminants and pathogens and are consumed by many fishes and birds. Benefits of invasive bivalves are particularly relevant in human-modified ecosystems. We summarize the multiple ecosystem services provided by invasive bivalves and recommend including the economically quantifiable services in the assessments of their economic impacts. We also highlight important ecosystem disservices by exotic bivalves, identify data limitations, and future research directions. This assessment should not be interpreted as a rejection of the fact that invasive mussels have negative impacts, but as an attempt to provide additional information for scientists, managers, and policymakers.

Fungi in Freshwaters: Prioritising Aquatic Hyphomycetes in Conservation Goals

Deprivation of protection for aquatic hyphomycetes is disturbing because they are key players in freshwater ecosystems across the globe. To attain a more holistic conservation paradigm for biodiversity in freshwaters, it is necessary to broaden our ecological perception of microfungi, mainly in aquatic hyphomycetes. A considerable groundwork still needs to be accomplished in progressing towards conserving aquatic hyphomycetes. Overcoming the paucity of information regarding the rare and endangered species, biogeography and above all, a global biodiversity database, would be a significant contribution in the initiation of an overarching conservation strategy for aquatic hyphomycetes. Being aware that the biodiversity decline in freshwaters is alarming, here we seek to explore why biodiversity data of aquatic hyphomycetes are missing. This article closely examines the threats to the biodiversity of aquatic hyphomycetes and freshwater ecosystems. Moving forward, we advocate a structured approach to gaining a thorough understanding to embrace aquatic hyphomycetes biodiversity into the conservation strategies. Including aquatic hyphomycetes in the conservation objectives may attract more funding opportunities for global surveys to initiate a fungal inclusive conservation era. Fungal conservation ventures can profit from interdisciplinary collaborations and cutting-edge science and technology, leading to informed decision making for biodiversity assessment and management.