PROBABILITY OF TREE SEEDLING ESTABLISHMENT CHANGES ACROSS A FOREST–OLD FIELD EDGE GRADIENT

Forest edges affect many aspects of plant communities, causing changes in microclimate, species composition, and community structure. However, the direct role of edges in regulating forest regeneration is relatively unknown. The pattern of tree establishment across a forest–old field edge was experimentally examined to determine the response of three tree species to the edge gradient. We placed 100 1-m2 plots in a 90 3 90 m grid that began 30 m inside the forest, extended across the edge, and ended at 60 m into the old field. Into each plot, we planted seeds of Acer rubrum, Acer saccharum, and Quercus palustris. Emergence increased with distance into the field for both A. saccharum and Q. palustris. Emergence for A. rubrum increased from forest to field, reaching a maximum near 20 m into the field, and then declined with further distance. Nearly all A. rubrum seedlings died shortly after emergence. Survival of A. saccharum increased with distance into the old field, while survivorship of Q. palustris did not respond to the edge gradient. Establishment probabilities increased with distance into the old field for both A. saccharum and Q. palustris. Growth of Q. palustris and allocation patterns of A. saccharum also varied across the edge gradient. These results suggest that edges have complex, speciesspecific effects on tree establishment and growth that can influence the spatial pattern and species composition of regenerating forests

Shifting forward: Urban ecology in perspective

The world has become urban; cities increasingly shape our worldviews, relation to other species, and the large-scale, long-term decisions we make. Cities are nature, but they need to align better with other ecosystems to avoid accelerating climate change and loss of biodiversity. We need a science to guide urban development across the diverse realities of global cities. This need can be met, in part, by shifts in urban ecology and its linkages to related sciences. This perspective is a “synthesis of syntheses”, consolidating ideas from the other articles in the Special Section. It re-examines the role of urban ecology, and explores its integration with other disciplines that study cities. We conclude by summarizing the next steps in the ongoing shift in urban ecology, which is fast becoming an integral part of urban studies

Democratization of ecosystem services—a radical approach for assessing nature’s benefits in the face of urbanization

OBJECTIVES : (1) To evaluate how ecosystem services may be utilized to either reinforce or fracture the planning and development practices that emerged from segregation and economic exclusion; (2) To survey the current state of ecosystem service assessments and synthesize a growing number of recommendations from the literature for renovating ecosystem service analyses. METHODS : Utilizing current maps of ecosystem service distribution in Bushbuckridge Local Municipality, South Africa, we considered how a democratized process of assessing ecosystem services will produce a more nuanced representation of diverse values in society and capture heterogeneity in ecosystem structure and function. RESULTS : We propose interventions for assessing ecosystem services that are inclusive of a broad range of stakeholders’ values and result in actual quantification of social and ecological processes. We demonstrate how to operationalize a pluralistic framework for ecosystem service assessments. CONCLUSION : A democratized approach to ecosystem service assessments is a reimagined path to rescuing a poorly implemented concept and designing and managing future socialecological systems that benefit people and support ecosystem integrity. It is the responsibility of scientists who do ecosystem services research to embrace more complex, pluralistic frameworks so that sound and inclusive scientific information is utilized in decision-making.The National Science Foundation under Grant No. RCN 1140070.https://www.tandfonline.com/loi/tehs20am2019Educational Psycholog

The relational shift in urban ecology: From place and structures to multiple modes of coproduction for positive urban futures

This perspective emerged from ongoing dialogue among ecologists initiated by a virtual workshop in 2021. A transdisciplinary group of researchers and practitioners conclude that urban ecology as a science can better contribute to positive futures by focusing on relationships, rather than prioritizing urban structures. Insights from other relational disciplines, such as political ecology, governance, urban design, and conservation also contribute. Relationality is especially powerful given the need to rapidly adapt to the changing social and biophysical drivers of global urban systems. These unprecedented dynamics are better understood through a relational lens than traditional structural questions. We use three kinds of coproduction—of the social-ecological world, of science, and of actionable knowledge—to identify key processes of coproduction within urban places. Connectivity is crucial to relational urban ecology. Eight themes emerge from the joint explorations of the paper and point toward social action for improving life and environment in urban futures

Target-dependence of sensory neurons: An ultrastructural comparison of axotomised dorsal root ganglion neurons with allowed or denied reinnervation of peripheral targets

Evidence is emerging for a role of rough endoplasmic reticulum (RER) in the form of stress granules, the unfolded protein response and protein bodies in the response of neurons to injury and in neurodegenerative diseases. Here, we have studied the role of the peripheral target in regulating the RER and polyribosomes of Nissl bodies in axotomised adult cat dorsal root ganglion (DRG) neurons where axonal regeneration and peripheral target reinnervation was either allowed or denied. Retrograde labelling with horseradish peroxidise was used as an independent marker to enable selection of only those DRG neuronal cell bodies with axons in the injured intercostal nerves. Indications of polyribosomal dispersal were seen by 6 h following axotomy, and by 24 h the normal orderly arrangement of lamellae of RER in Nissl bodies had become disorganised. These ultrastructural changes preceded light microscopical chromatolysis by 1–3 d. The retrograde response was maximal 8–32 d after axotomy. Clusters of debris-laden satellite cells/macrophages were present at this time but no ultrastructural evidence of neuronal apoptosis or necrosis was seen and there were no differences in the initial retrograde response according to the type of injury. By 64 d following axotomy with reinnervation, approximately half the labelled DRG neurons showed restoration of the orderly arrangement of RER and polyribosomes in their Nissl bodies. This was not seen after axotomy with reinnervation denied. We propose that the target-dependent changes in Nissl body ultrastructure described here are part of a continuum that can modify neuronal protein synthesis directed towards growth, maintenance or death of the neuron. This represents a possible structural basis for mediating the varied effects of neurotrophic interactions.I. P. Johnson and T. A. Sear