When provided individually, both the serotonin (5-HT 1A )-receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) and environmental enrichment (EE) enhance behavioral outcome and reduce histopathology after experimental traumatic brain injury (TBI). The aim of this study was to determine whether combining these therapies would yield greater benefit than either used alone. Anesthetized adult male rats received a cortical impact or sham injury and then were randomly assigned to enriched or standard (STD) housing, where either 8-OH-DPAT (0.1 mg/kg) or vehicle (1.0 mL/kg) was administered intraperitoneally once daily for 3 weeks. Motor and cognitive assessments were conducted on post-injury days 1-5 and 14-19, respectively. CA1/ CA3 neurons and choline acetyltransferase-positive (ChAT þ ) medial septal cells were quantified at 3 weeks. 8-OH-DPAT and EE attenuated CA3 and ChAT þ cell loss. Both therapies also enhanced motor recovery, acquisition of spatial learning, and memory retention, as verified by reduced times to traverse the beam and to locate an escape platform in the water maze, and a greater percentage of time spent searching in the target quadrant during a probe trial in the TBI þ STD þ 8-OH-DPAT, TBI þ EE þ 8-OH-DPAT, and TBI þ EE þ vehicle groups versus the TBI þ STD þ vehicle group ( p 0.0016). No statistical distinctions were revealed between the TBI þ EE þ 8-OH-DPAT and TBI þ EE þ vehicle groups in functional outcome or CA1/CA3 cell survival, but there were significantly more ChAT þ cells in the former ( p ¼ 0.003). These data suggest that a combined therapeutic regimen of 8-OH-DPAT and EE reduces TBI-induced ChAT þ cell loss, but does not enhance hippocampal cell survival or neurobehavioral performance beyond that of either treatment alone. The findings underscore the complexity of combinational therapies and of elucidating potential targets for TBI.

Nature is often more diverse than expected with multiple species appearing to occupy the same niche. This observation is especially perplexing when the co‐occurring species are cryptic (i.e. only distinguishable via molecular markers), because phenotypic similarity is expected to correspond with strong niche overlap. One way that phenotypically similar species can coexist is if fine‐scale phenotypic differences affect how species interact with other members of the community that ultimately results in performance tradeoffs. An alternative explanation for co‐occurrence is that phenotypic similarity leads to ecological equivalence allowing species to co‐occur for long periods. We tested whether three phenotypically similar amphipod species that co‐occur exhibit performance tradeoffs that may allow them to stably coexist in lakes. We found that despite their similarity the three species differed in how well they performed in competition with each other and their ability to avoid predation by fish and invertebrate predators. In some species comparisons, performance tradeoffs were apparent with species that perform well against heterospecifics performing poorly against predators and vice versa. We also found evidence for direct antagonistic interactions among amphipod species, in the form of wounding, which may play a role in structuring amphipod assemblages. Finally, the two species with the most similar phenotypes showed comparable responses to competitors and predators, which suggests that long‐term co‐occurrence via ecological equivalence may also be important in this system. Collectively, our results suggest that a mix of performance tradeoffs and ecological equivalence may allow for higher diversity than expected in amphipod assemblages.

We present palaeoeconomy reconstructions for pre-modern agriculture; we select, wherever required, features and parameter values specific for the Cucuteni-Trypillia Cultural unity (CTU: 5,400-2700 BC, mostly the territory of modern Ukraine, Moldova and Romania). We verify the self-consistency and viability of the archaeological evidence related to all major elements of the agricultural production cycle within the constraints provided by environmental and technological considerations. The starting point of our analysis is the palaeodiet structure suggested by archaeological data, stable isotope analyses of human remains, and palynology studies in the CTU area. We allow for the archeologically attested contributions of domesticated and wild animal products to the diet, develop plausible estimates of the yield of ancient cereal varieties cultivated with ancient techniques, and quantify the yield dependence on the time after initial planting and on rainfall (as a climate proxy). Our conclusions involve analysis of the labour costs of various seasonal parts of the agricultural cycle of both an individual and a family with a majority of members that do not engage in productive activities. Finally, we put our results into the context of the exploitation territory and catchment analysis, to project various subsistence strategies into the exploitation territory of a farming settlement.The simplest economic complex based on cereals, domestic and wild animal products, with fallow cropping, appears to be capable of supporting an isolated, relatively small farming community of 50-300 people (2-10 ha in area) even without recourse to technological improvements such as the use of manure fertiliser. Our results strongly suggest that dairy products played a significant role in the dietary and labour balance. The smaller settlements are typical of the earliest Trypillia A but remain predominant at the later stages. A larger settlement of several hundred people could function in isolation, perhaps with a larger fraction of cereals in the diet, only with technological innovations, such as manure fertiliser and, most importantly, ard tillage. The ard relieves radically the extreme time pressure associated with soil preparation for sowing. It appears that very large settlements of a few hundred hectares in area could function only if supported by satellite farming villages and stable exchange networks. In turn, this implies social division of labour and occupation, sufficiently complex social relations, stable exchange channels, etc.: altogether, a proto-urban character of such settlements. We also discuss, quantify and assess some strategies to mitigate the risks of arable agriculture associated with strong temporal fluctuations in the cereal yield, such as manure fertilisation, increased fraction of cereals in the diet combined with producing grain surplus for emergency storage.

Agricultural activity can alter water quality and quantity resulting in lakes facing increasing interactive stressors including eutrophication, suspended sediment and water withdrawal. This study examined the relationships between water depth, water quality and algae in shallow agricultural lakes in the lower Mississippi River Basin (LMRB) to assess how lake depth influences algal structure and function, focusing on factors that typically regulate growth, that is, light, temperature and nutrients. Lake water and sediment cores were collected in shallow (mean = 0.8 m) and deep (mean = 1.7 m) locations in three lakes seasonally for 1 year. Additionally, interactive effects of light and temperature on algal growth were investigated through a laboratory experiment to determine the relative importance of each in regulating algal biomass and net oxygen production. In these shallow, turbid, eutrophic lakes, deeper water had lower nutrient concentrations and temperature across all seasons and clearer water in the summer. Shallow areas had more phytoplankton and periphyton. Water temperature had a stronger correlation than light with both phytoplankton and periphyton biomass. Algal biomass generally decreased with increasing water temperature, but biomass was better predicted by increasing nitrogen availability, and productivity declined with greater phosphorus availability. Water depth was therefore likely influencing different locations of the same lake towards different algal stable states. Mitigating excess algal production is an important goal towards limiting hypoxic conditions in the LMRB, and increasing water storage could help moderate temperature, nutrients and turbidity effects that contribute to algal blooms in lakes receiving agricultural runoff.

Secondary production is the generation of new heterotrophic biomass and is analogous to net primary production of autotrophs. For an individual, secondary production is equivalent to the growth of new somatic or reproductive biomass over time. For a population, secondary production comprises the total formation of biomass, regardless of its fate, by all individuals within the population over a defined time interval. Some consider secondary production the ultimate measure of population ‘success’ because it incorporates aspects of survivorship, individual growth rate, biomass, development time, and reproduction. Secondary production is often associated with the subfield of ecosystem ecology because it is a flux with dimensions of mass or energy area-2 time-1. This flux is typically estimated with an ecological currency (e.g., joules, carbon, organic matter) that can be compared with other ecosystem processes such as primary production or decomposition. Secondary production estimates are thus useful for placing species, populations, and communities within a broader ecosystem context, and for facilitating the study of energy flows and ecological efficiencies in trophic interactions. The vast majority of secondary production estimates have come from freshwater and marine ecosystems, while there are very few studies in terrestrial ecosystems. In the aquatic studies, although early work was largely focused on fishes, most estimates are for benthic invertebrates; some studies have quantified production of zooplankton, bacteria, and fungi. Early studies of secondary production were focused on methodology and basic comparisons among populations or communities. More recent literature has expanded the application of secondary production toward broader ecological questions related to, for example, energy and chemical flows in food webs, species interaction strengths, and responses to anthropogenic stressors. This bibliography focuses on primary literature that highlights key historic, conceptual, theoretical, and applied papers related to secondary production. Papers highlighted herein are biased toward freshwaters and invertebrates because of their dominance in the literature, but key references that extend to other habitats and taxa are included.