Search

Conservation of species and ecosystems is increasingly difficult because anthropogenic impacts are pervasive and accelerating. Under this rapid global change, maximizing conservation success requires a paradigm shift from maintaining ecosystems in idealized past states toward facilitating their adaptive and functional capacities, even as species ebb and flow individually. Developing effective strategies under this new paradigm will require deeper understanding of the long-term dynamics that govern ecosystem persistence and reconciliation of conflicts among approaches to conserving historical versus novel ecosystems. Integrating emerging information from conservation biology, paleobiology, and the Earth sciences is an important step forward on the path to success. Maintaining nature in all its aspects will also entail immediately addressing the overarching threats of growing human population, overconsumption, pollution, and climate change.

Humans now play a major role in altering Earth and its biota. Finding ways to ameliorate human impacts on biodiversity and to sustain and restore the ecosystem services on which we depend is a grand scientific and societal challenge. Conservation paleobiology is an emerging discipline that uses geohistorical data to meet these challenges by developing and testing models of how biota respond to environmental stressors. Here we (a) describe how the discipline has already provided insights about biotic responses to key environmental stressors, (b) outline research aimed at disentangling the effects of multiple stressors, (c) provide examples of deliverables for managers and policy makers, and (d) identify methodological advances in geohistorical analysis that will foster the next major breakthroughs in conservation outcomes. We highlight cases for which exclusive reliance on observations of living biota may lead researchers to erroneous conclusions about the nature and magnitude of biotic change, vulnerability, and resilience.

Previous research combining data on the abundance of benthic invertebrates living in the northernmost section of the Barnegat Bay-Little Egg Harbor estuary with data on water quality suggested a community composition consistent with anthropogenic eutrophication. This part of the estuary, however, experiences both high-nutrient and low-salinity environmental conditions, which are both ecologically stressful to sensitive species and favorable to opportunistic species, complicating assessments of the direct effects of anthropogenic eutrophication. Here, geohistorical baselines were derived from molluscan death assemblages from four localities along a north-south gradient in the bay--two northern low-salinity, high-nutrient sites and two southern high-salinity, low-nutrient sites--to disentangle the effects of salinity and nutrient enrichment on the composition of benthic communities. Disturbance in the northern section of the estuary from freshwater input has been relatively consistent for thousands of years, but nutrient enrichment is a more recent stressor, developing only in the past few decades. The cause of the disturbed benthic community is unlikely to be anthropogenic eutrophication, if there is little discordance between the living and the death assemblage in the northern, low-salinity section of the bay. Comparisons of rank-order abundance (Spearman's rho) and taxonomic similarity (Jaccard-Chao index) of the living and death assemblages along the north-south gradient, however, indicate that compositional shifts occur at the northern sites only. A multivariate index analysis, M-AMBI, which integrates the AZTI Marine Biotic Index, a biotic index based on species sensitivity/tolerance to disturbances, with Shannon diversity and species richness, shows a similar pattern: ecological status shifts (from undisturbed to disturbed) in the northern but not southern sites along the north-south salinity gradient. These independent lines of evidence corroborate the inference that it is most likely anthropogenic eutrophication (and not salinity) disturbance driving observed patterns in benthic community composition. Further sampling and incorporation of geohistorical data into ongoing benthic monitoring in the estuary is recommended to establish ecological baselines where none exist, guide restoration planning, and assess the success of restoration efforts. KEY WORDS: Barnegat Bay, bivalves, eutrophication, gastropods, geohistorical data, live-dead analysis, M-AMBI. salinity, INTRODUCTION Barnegat Bay-Little Egg Harbor is a 280 k[m.sup.2] estuary located on the southern coast of New Jersey, separated from the Atlantic Ocean by a barrier island system (Fig. 1). [...]

ABSTRACT Conservation paleobiology aims to apply data from geohistorical records, such as fossils and their associated sediments, to the conservation of biodiversity and ecosystem services. Integrating geohistorical data into conservation/restoration [...]