Conservation Paleobiology as a Tool to Define Reference Conditions in Naturally Stressed Transitional Settings: Micropaleontological Insights from the Holocene of the Po Coastal Plain (Italy)

What is conservation paleobiology? Tracking 20 years of research and development

Conservation paleobiology has coalesced over the last two decades since its formal coining, united by the goal of applying geohistorical records to inform the conservation, management, and restoration of biodiversity and ecosystem services. Yet, the field is still attempting to form an identity distinct from its academic roots. Here, we ask a deceptively simple question: What is conservation paleobiology? To track its development as a field, we synthesize complementary perspectives from a survey of the scientific community that is familiar with conservation paleobiology and a systematic literature review of publications that use the term. We present an overview of conservation paleobiology’s research scope and compare survey participants’ perceptions of what it is and what it should be as a field. We find that conservation paleobiologists use a variety of geohistorical data in their work, although research is typified by near-time records of marine molluscs and terrestrial mammals collected over local to regional spatial scales. Our results also confirm the field’s broad disciplinary basis: survey participants indicated that conservation paleobiology can incorporate information from a wide range of disciplines spanning conservation biology, ecology, historical ecology, paleontology, and archaeology. Finally, we show that conservation paleobiologists have yet to reach a consensus on how applied the field should be in practice. The survey revealed that many participants thought the field should be more applied but that most do not currently engage with conservation practice. Reflecting on how conservation paleobiology has developed over the last two decades, we discuss opportunities to promote community cohesion, strengthen collaborations within conservation science, and align training priorities with the field’s identity as it continues to crystallize.

Long-Term Shifts in Faunal Composition of Freshwater Mollusks in Spring-Fed Rivers of Florida

Florida’s freshwater spring and river ecosystems have been deteriorating due to direct and indirect human impacts. However, while the conservation and restoration strategies employed to mitigate these effects often rely on faunal surveys that go back several decades, the local ecosystem shifts tend to have much deeper roots that predate those faunal surveys by centuries or millennia. Conservation paleobiology, an approach which enhances our understanding of the past states of ecosystems, allows for comparison of modern faunal communities with those prior to significant human impacts. This study examines the historical record of freshwater mollusk assemblages from two spring-fed river systems, the Wakulla and Silver/Ocklawaha Rivers. Specifically, we compared fossil assemblages (latest Pleistocene - early Holocene) and live mollusk assemblages in the two targeted river systems. Bulk sampling of the fossil record (20 sites; 70 samples; 16,314 specimens) documented relatively diverse mollusk assemblages that consist of a suite of native freshwater species that is similar across the studied systems. In contrast, sampling of live communities (24 sites; 138 samples; 7,572 specimens) revealed depauperate species assemblies characterized by the absence of multiple native freshwater species commonly found in fossil samples, the widespread presence of introduced species, and dominance of brackish-tolerant species at the lower Wakulla River sites. Unlike fossil mollusk assemblages, live mollusk assemblages differ notably between the two river systems due to differences in relative abundance of introduced species (Melanoides tuberculata and Corbicula fluminea) and the presence of brackish-tolerant mollusks in the coastally influenced Wakulla River. The diverse, exclusively freshwater mollusk associations comparable across multiple river systems documented in the fossil record provide a historical perspective on the past state of freshwater river ecosystems complementing data provided by modern surveys. The conservation paleobiology approach used in this study reinforces the importance of considering the historical ecology of an ecosystem and the utility of the fossil record in providing a historical perspective on long-term faunal changes.

Benthic Foraminiferal Indices and Environmental Quality Assessment of Transitional Waters: A Review of Current Challenges and Future Research Perspectives

Transitional waters straddle the interface between marine and terrestrial biomes and, among others, include fjords, bays, lagoons, and estuaries. These coastal systems are essential for transport and manufacturing industries and suffer extensive anthropogenic exploitation of their ecosystem services for aquaculture and recreational activities. These activities can have negative effects on the local biota, necessitating investigation and regulation. As a result of this, EcoQS (ecological quality status) assessment has garnered great attention as an essential aspect of governmental bodies’ legislative decision-making process. Assessing EcoQS in transitional water ecosystems is problematic because these systems experience high natural variability and organic enrichment and often lack information about their pre-human impact, baseline, or “pristine” reference conditions, knowledge of which is essential to many commonly used assessment methods. Here, foraminifera can be used as environmental sentinels, providing ecological data such as diversity and sensitivity, which can be used as the basis for EcoQS assessment indices. Fossil shells of foraminifera can also provide a temporal aspect to ecosystem assessment, making it possible to obtain reference conditions from the study site itself. These foraminifera-based indices have been shown to correlate not only with various environmental stressors but also with the most common macrofaunal-based indices currently employed by bodies such as the Water Framework Directive (WFD). In this review, we firstly discuss the development of various foraminifera-based indices and address the challenge of how best to implement these synergistically to understand and regulate human environmental impact, particularly in transitional waters, which have historically suffered disproportionate levels of human impact or are difficult to assess with standard EcoQS methods. Further, we present some case studies to exemplify key issues and discuss potential solutions for those. Such key issues include, for example, the disparate performance of multiple indices applied to the same site and a proper assignment of EcoQS class boundaries (threshold values) for each index. Disparate aptitudes of indices to specific geomorphologic and hydrological regimes can be leveraged via the development of a site characteristics catalogue, which would enable the identification of the most appropriate index to apply, and the integration of multiple indices resulting in more representative EcoQS assessment in heterogenous transitional environments. In addition, the difficulty in assigning threshold values to systems without analogous unimpacted reference sites (a common issue among many transitional waters) can be overcome by recording EcoQS as an ecological quality ratio (EQR). Lastly, we evaluate the current status and future potential of an emerging field, genetic biomonitoring, focusing on how these new techniques can be used to increase the accuracy of EcoQS assessment in transitional systems by supplementing more established morphology-based methods.