Rewilding som planmål i Antropocæn

Der er langt fra det moderne kulturlandskab med monotone marker og netværk af bebyggelser med veje og jernbaner til det vildnis, som var biodiversitetens vugge. De arter, der udgør biodiversiteten i dag, opstod i de forhistoriske økosystemer, hvor floderne gik over bredderne, stormfald og brande raserede skove og krat, og elefanter, næsehorn, heste, urokser og andre store dyr trampede og gnavede sig gennem økosystemerne. Det er netop menneskets tæmning af vildnisset, som er årsagen til biodiversitetskrisen. Det traditionelle svar på biodiversitetskrisen har været, at naturen er syg og truet og derfor har brug for vores pleje og omsorg. Denne forvaltningsmodel udfordres i dag af rewilding, som i stedet foreslår, at vi bygger på naturens evne til selvforvaltning, og i særdeleshed de store dyrs vigtige funktioner i økosystemerne. Uanset om målet er traditionel naturpleje eller rewilding, så lider biodiversiteten under pladsmangel, så der er brug for en rumlig planlægning, hvor naturen indgår som planmål. Rewilding kræver desuden store sammenhængende områder, og dem får vi kun, hvis der er politisk vilje til det

Ecospace:a unified framework for understanding variation in terrestrial biodiversity

AbstractUnderstanding patterns in biodiversity is a core ambition in ecological research. Existing ecological theories focusing on individual species, populations, communities, or niches aid in understanding the determinants of biodiversity patterns, yet very few general models for biodiversity have emerged from simplistic approaches. We propose that a systematic, low-dimensional representation of environmental space with building blocks adopted from gradient, niche, metapopulation and assembly theory may unite old and new aspects of biodiversity theory and improve our understanding of variation in terrestrial biodiversity.We propose the term ecospace to cover the local conditions and resources underlying diversity. Our definition of ecospace encompasses abiotic position, biotic expansion and spatiotemporal continuity, which all affect the biodiversity of a biotope (α-diversity). Position refers to placement along abiotic gradients such as temperature, soil pH and fertility, leading to environmental filtering known from classical community theory. Expansion represents the build-up and diversification of organic matter that are not strictly given by position. Continuity refers to the spatiotemporal extension of position and expansion.Biodiversity is scale dependent. The contribution of one biotope to large scale diversity must be estimated by considering its unique contribution to the species richness of the surrounding landscape or region or to the biodiversity of the entire planet. In addition to the relationship between ecospace and biotope richness (α-diversity), we also propose a relation between the uniqueness of the biotope ecospace and the unique contribution of species to the surrounding larger-scale richness.Whereas the impacts of ecospace position and continuity on biodiversity have been studied in isolation, studies comparing or combining them are rare. Furthermore, biotic expansion has never been fully developed as a determinant of biodiversity, ignoring the megadiverse carbon-depending groups of insects and fungi. Precursors of the ecospace concept have been presented over the last 70 years, but they were never fully developed conceptually for terrestrial biodiversity or applied to prediction of biodiversity.Ecospace unites classical and – at times – contradicting theories such as niche theory, island biogeography theory and a suite of community assembly theories into one framework for further development of a general theory of terrestrial biodiversity

Predicting provenance of forensic soil samples:linking soil to ecological habitats by metabarcoding and supervised classification

Environmental DNA (eDNA) is increasingly applied in ecological studies, including studies with the primary purpose of criminal investigation, in which eDNA from soil can be used to pair samples or reveal sample provenance. We collected soil eDNA samples as part of a large national biodiversity research project across 130 sites in Denmark. We investigated the potential for soil eDNA metabarcoding in predicting provenance in terms of environmental conditions, habitat type and geographic regions. We used linear regression for predicting environmental gradients of light, soil moisture, pH and nutrient status (represented by Ellenberg Indicator Values, EIVs) and Quadratic Discriminant Analysis (QDA) to predict habitat type and geographic region. eDNA data performed relatively well as a predictor of environmental gradients (R2 > 0.81). Its ability to discriminate between habitat types was variable, with high accuracy for certain forest types and low accuracy for heathland, which was poorly predicted. Geographic region was also less accurately predicted by eDNA. We demonstrated the application of provenance prediction in forensic science by evaluating and discussing two mock crime scenes. Here, we listed the plant species from annotated sequences, which can further aid in identifying the likely habitat or, in case of rare species, a geographic region. Predictions of environmental gradients and habitat types together give an overall accurate description of a crime scene, but care should be taken when interpreting annotated sequences, e.g. due to erroneous assignments in GenBank. Our approach demonstrates that important habitat properties can be derived from soil eDNA, and exemplifies a range of potential applications of eDNA in forensic ecology

Exploring a natural baseline for large-herbivore biomass in ecological restoration

1 - Large herbivores provide key ecosystem processes, but have experienced massive historical losses and are under intense pressure, leaving current ecosystems with dramatically simplified faunas relative to the long-term evolutionary norm. Hampered by a shifting baseline, natural levels of large-herbivore biomass are poorly understood and seldom targeted. This ‘Decade of ecosystem restoration’ calls for evidence-based targets for restoring the natural diversity and biomass of large herbivores. 2 - We apply the scaling of the consumer–producer relationship to a global dataset of large-herbivore density in natural areas. The analyses reveal that African ecosystems generally have much higher large-herbivore biomass and also the strongest consumer–producer relationship. For Europe, Asia and South America, there are no significant relationships with primary productivity indicative of impoverished faunas. Compared to expectations from the African scaling relation, large-herbivore biomass in ecosystems outside Africa is considerably lower than expected. 3 - Synthesis and applications. Ecological restoration and rewilding entail restoration of a natural grazing process. Our findings indicate that many nature reserves are depleted in large-herbivore biomass, judged from their primary productivity. Meanwhile, overexploitation by seasonal livestock grazing takes place in other areas. It is thus difficult, but urgent, to reach scientific consensus regarding a natural baseline for large-herbivore biomass. Until such agreement has been reached, we recommend to manage, or rewild, large herbivores in year-round near-natural grazing and without predefined density targets, but following natural and fluctuating resource availability with minimal management intervention. The establishment of experimental rewilding sites with reactive herbivore management is needed to further advance our understanding of natural grazing density