Metacommunity assembly and sorting in newly formed lake communities

new habitats are created, community assembly may follow independent trajectories, since the relative importance of dispersal limitation, priority effects, species interactions, and environmental gradients can vary as assembly proceeds. Unfortunately, tracking community colonization and composition across decades is challenging. We compiled a multiyear community composition data set and reconstructed past communities with remains from sediment cores to investigate cladoceran assembly dynamics in six older (1920s) and two more recently formed (1950s) lakes. We found that current communities cluster along a gradient of thermal stratification that is known to influence predation intensity. Assembling communities showed evidence for a greater influence of species sorting and a reduced influence of spatial structure since the first colonizations. However, lake community trajectories varied considerably, reflecting different colonization sequences among lakes. In the older lakes, small-bodied cladocerans often arrived much earlier than large-bodied cladocerans, while the two younger lakes were colonized much more rapidly, and one was quickly dominated by a large-bodied species. Thus, by combining contemporary community data with paleoecological records, we show that assembly history influences natural community structure for decades while patterns of ecological sorting develop.     

The Maine Vernal Pool Mapping and Assessment Program: Engaging Municipal Officials and Private Landowners in Community-Based Citizen Science

The Vernal Pool Mapping and Assessment Program (VPMAP) was initiated in 2007 to create a vernal pool database as a planning tool to foster local compliance with new state vernal pool regulations. In the northeastern United States, vernal pools are seasonal wetlands that provide critical breeding habitat for a number of amphibians and invertebrates and provide important resting and foraging habitat for some rare and endangered state-listed species. Using participant observation, interviews, and focus groups, we examined the engagement of municipal officials and private landowners in VPMAP. Important outcomes of municipal and landowner engagement included mobilization of town support for proactive planning, improved awareness and understanding of vernal pools, and increased interactions between program coordinators, municipal officials, and private landowners. Challenges to municipal and landowner engagement included an inconsistency in expectations between coordinators and municipal officials and a lack of time and sufficient information for follow-up with landowners participating in VPMAP. Our study highlights the importance of developing relationships among coordinators, municipal officials, and private landowners in facilitating positive outcomes for all stakeholders and for effective resource management. We suggest an expanded citizen science model that focuses on improving two-way communication among project coordinators, municipal officials, and local citizens and places communication with private landowners on par with volunteer citizen scientist recruitment and field training. Lessons learned from this research can inform the design and implementation of citizen science projects on private land.     

Entangled recovery: refugee encounters in community gardens

ABSTRACT

Community gardens are often considered to be therapeutic landscapes capable of supporting wellbeing and recovery particularly for members of vulnerable or disadvantaged groups such as refugees. This is regularly identified as resulting from the capacity for communal garden activities to enable realisation of self-efficacy, the formation of social connections and the assumed benefits of “being” in nature. These approaches tend to privilege anthropocentric perspectives that perpetuate conceptions of a human/nature binary. As such, existing literature has paid little attention to the role in refugee recovery of the visceral, affective force of matter encountered in the embodied act of gardening. By adopting such an approach, this paper aims to tease out the particularities of how bodies in these places engage with the ecological experiences of their new homes. Such encounters are never simply harmonious. They can reinforce dislocation while concurrently providing sites where gardeners are able to strengthen their adaptive capabilities via experimentation. To understand the utility of community gardening to support refugee recovery we argue it is necessary to not only attend to human participants and issues of design, infrastructure, and garden management, but also to the impact of particular forms of human and more-than-human entanglements that emerge in these spaces. In so doing we suggest that the notion of community and belonging in these settings should be broadened to more deeply engage with the more-than-human. To explore this, we focus on a small-scale, in-depth case study of a food-producing garden established for Burmese refugees in Canberra, Australia.     

A spatiotemporal analysis of cattle herd movement in relation to drinking-water sources: implications for Cryptosporidium control in rural Kenya

Environmental Science and Pollution Research - Given the increasing evidence that domestic contact with livestock is a risk factor for child diarrhoea in low- and middle-income countries, there...     

Instream Restoration to Improve the Ecohydrologic Function of a Subalpine Meadow: Pre‐implementation Modeling with HEC‐RAS

Vegetation in subalpine meadows in the Sierra Nevada Mountains is particularly vulnerable to lowering of groundwater levels because wet meadow vegetation is reliant upon shallow groundwater during the dry summer growing season. These ecosystems are especially vulnerable to channel incision as meadow aquifers are hydrologically connected to tributaries, and many have not yet recovered from previous anthropogenic influences. While instream restoration projects have become a common approach, lack of postrestoration monitoring and communication often result in a trial‐and‐error approach. In this study we demonstrate that preimplementation modeling of possible instream restoration solutions, chosen to raise stream stage and subsequently groundwater levels, is a useful tool for evaluating and comparing potential channel modifications. Modeling allows us to identify strategic locations and specific methods. Results show additional sediment depth and roughness on tributaries along with introduced woody debris (simulated by high roughness) on the Tuolumne River are the most effective means of raising stream stage. Results demonstrate that restoration efforts are most efficient in tributary streams. Managers and planners can more efficiently direct resources while minimizing the potential for negative impacts or failed restoration projects by modeling the possible effects of multiple restoration scenarios before implementation.     

‘Natural’ disaster? A retrospect into the causes of the late-2004 typhoon disaster in Eastern Luzon,Philippines

Between 14 November and 4 December 2004, four successive tropical depressions and typhoons lashed the Eastern coast of Luzon in the Philippines. Heavy rainfall triggered massive landslides and devastating flash floods, which brought tremendous damage and killed more than 1600 people. Immediately after the disaster, there was a media and political consensus to incrimate ‘extraordinary’ natural phenomena and widespread deforestation as responsible for the catastrophe. We argue that the tragedy that befell the municipalities of General Nakar, Infanta and Real, among other devastated areas, is enmeshed in a deeper tangle of causal factors that are political, socio-economic and demographic in nature. These factors include unmanaged population growth, difficult access to land and resources, corruption within the government, and power of the elite.     

Microbial community phylogenetic and trait diversity declines with depth in a marine oxygen minimum zone

Oxygen minimum zones (OMZs) are natural physical features of the world's oceans. They create steep physiochemical gradients in the water column, which most notably include a dramatic draw down in oxygen concentrations over small vertical distances (<100 m). Microbial communities within OMZs play central roles in ocean and global biogeochemical cycles, yet we still lack a fundamental understanding of how microbial biodiversity is distributed across OMZs. Here, we used metagenomic sequencing to investigate microbial diversity across a vertical gradient in the water column during three seasons in the Eastern Tropical South Pacific (ETSP) OMZ. Based on analysis of small subunit ribosomal RNA (SSU rRNA) gene fragments, we found that both taxonomic and phylogenetic diversity declined steeply along the transition from oxygen-rich surface water to the permanent OMZ. We observed similar declines in the diversity of protein-coding gene categories, suggesting a decrease in functional (trait) diversity with depth. Metrics of functional and trait dispersion indicated that microbial communities are phylogenetically and functionally more overdispersed in oxic waters, but clustered within the OMZ. These dispersion patterns suggest that community assembly drivers (e.g., competition, environmental filtering) vary strikingly across the oxygen gradient. To understand the generality of our findings, we compared OMZ results to two marine depth gradients in subtropical oligotrophic sites and found that the oligotrophic sites did not display similar patterns, likely reflecting unique features found in the OMZ. Finally, we discuss how our results may relate to niche theory, diversity-energy relationships and stress gradients.     

Phosphorus in Phoenix: a budget and spatial representation of phosphorus in an urban ecosystem

As urban environments dominate the landscape, we need to examine how limiting nutrients such as phosphorus (P) cycle in these novel ecosystems. Sustainable management of P resources is necessary to ensure global food security and to minimize freshwater pollution. We used a spatially explicit budget to quantify the pools and fluxes of P in the Greater Phoenix Area in Arizona, USA, using the boundaries of the Central Arizona-Phoenix Long-Term Ecological Research site. Inputs were dominated by direct imports of food and fertilizer for local agriculture, while most outputs were small, including water, crops, and material destined for recycling. Internally, fluxes were dominated by transfers of food and feed from local agriculture and the recycling of human and animal excretion. Spatial correction of P dynamics across the city showed that human density and associated infrastructure, especially asphalt, dominated the distribution of P pools across the landscape. Phosphorus fluxes were dominated by agricultural production, with agricultural soils accumulating P. Human features (infrastructure, technology, and waste management decisions) and biophysical characteristics (soil properties, water fluxes, and storage) mediated P dynamics in Phoenix. P cycling was most notably affected by water management practices that conserve and recycle water, preventing the loss of waterborne P from the ecosystem. P is not intentionally managed, and as a result, changes in land use and demographics, particularly increased urbanization and declining agriculture, may lead to increased losses of P from this system. We suggest that city managers should minimize cross-boundary fluxes of P to the city. Reduced P fluxes may be accomplished through more efficient recycling of waste, therefore decreasing dependence on external nonrenewable P resources and minimizing aquatic pollution. Our spatial approach and consideration of both pools and fluxes across a heterogeneous urban ecosystem increases the utility of nutrient budgets for city managers. Our budget explicitly links processes that affect P cycling across space with the management of other resources (e.g., water). A holistic management strategy that deliberately couples the management of P and other resources should be a priority for cities in achieving urban sustainability.     

Nuclear and mtDNA lineage diversity in wild and cultured Pacific lion-paw scallop, Nodipecten subnodosus (Baja California Peninsula, Mexico)

Pacific lion-paw scallops were collected from natural aggregations in Laguna Ojo de Liebre (Pacific Ocean), the Gulf of California, and from aquaculture facilities for genetic diversity analyses. Mitochondrial DNA sequencing uncovered two highly supported clades separated by 2.5% divergence. Data from ten microsatellite markers suggest individuals from these mitogroups are introgressed, raising questions about the mitotype origin. Some evidence suggests gene flow between La Paz and Ojo de Liebre; otherwise the Gulf of California and Ojo de Liebre are acting as two distinct populations. It is unclear whether translocations between sites have influenced the observed genetic structure or whether gene flow has been facilitated by past geologic events. Finally, scallops spawned for aquaculture are unique from the wild and have significantly less diversity. These results warrant the attention of managers and producers who should work to monitor and conserve genetic diversity in both wild and aquaculture populations.