Coupling PCSWMM and WASP to Evaluate Green Stormwater Infrastructure Impacts to Storm Sediment Loads in an Urban Watershed

We coupled rainfall–runoff and instream water quality models to evaluate total suspended solids (TSS) in Wissahickon Creek, a mid‐sized urban stream near Philadelphia, Pennsylvania. Using stormwater runoff and instream field data, we calibrated the model at a subdaily scale and focused on storm responses. We demonstrate that treating event mean concentrations as a calibration parameter rather than a fixed input can substantially improve model performance. Urban stormwater TSS concentrations vary widely in time and space and are difficult to represent simply. Suspended and deposited sediment pose independent stressors to stream biota and model results suggest that both currently impair stream health in Wissahickon Creek. Retrofitting existing detention basins to prioritize infiltration reduced instream TSS loads by 20%, suggesting that infiltration mitigates sediment more effectively than detention. Infiltrating stormwater from 30% of the watershed reduced instream TSS loads by 47% and cut the frequency of TSS exceeding 100 mg/L by half. Settled loads and the frequency of high TSS values were reduced by a smaller fraction than suspended loads and duration at high TSS values. A widely distributed network of infiltration‐focused projects is an effective stormwater management strategy to mitigate sediment stress. Coupling rainfall–runoff and water quality models is an important way to integrate watershed‐wide impacts and evaluate how management directly affects urban stream health.     

Agroecosystems,nitrogen-use efficiency,and nitrogen management

The global challenge of meeting increased food demand and protecting environmental quality will be won or lost in cropping systems that produce maize, rice, and wheat. Achieving synchrony between N supply and crop demand without excess or deficiency is the key to optimizing trade-offs amongst yield, profit, and environmental protection in both large-scale systems in developed countries and small-scale systems in developing countries. Setting the research agenda and developing effective policies to meet this challenge requires quantitative understanding of current levels of N-use efficiency and losses in these systems, the biophysical controls on these factors, and the economic returns from adoption of improved management practices. Although advances in basic biology, ecology, and biogeochemistry can provide answers, the magnitude of the scientific challenge should not be underestimated because it becomes increasingly difficult to control the fate of N in cropping systems that must sustain yield increases on the world's limited supply of productive farm land.     

Extrapair paternity in the swamp sparrow, <Emphasis Type="Italic">Melospiza georgiana</Emphasis>: male access or female preference?

Over the past two decades, the combination of molecular and field methods has revealed considerable variation in the level of extrapair fertilizations among socially monogamous birds. Models predicting extrapair young range in scale from a single population to multiple Orders, and there is no single, unifying theory for these reproductive tactics. We investigated proximate explanations of extrapair fertilizations in two subspecies of the swamp sparrow, Melospiza georgiana georgiana and Melospiza georgiana nigrescens, across a range of social and environmental conditions. The presence of extrapair young was best predicted by the size of two male plumage badges (one correlated with parental care and one with territorial aggression) relative to the badge size of their immediate neighbors, the interaction of these two measures, mean territory size, and the maximum size of the aggression badge among neighbors. The size of the male’s parental care badge (relative to neighbors) was negatively correlated with the probability of lost paternity. The relative size of the aggression badge was positively correlated with the presence of extrapair young when the parental care badge was small and negatively correlated when the badge was large. Controlling for these crown measures, males with larger territories were less likely to suffer losses in paternity. There was no effect of breeding density, breeding synchrony, their interaction, subspecies, or weather during the fertile period on the presence of extrapair young. These results suggest that female preference for males that provide more parental care (or preference for genes that convey this trait) plays a dominant role in extrapair interactions among swamp sparrows. Models based on female assessments of relative mate quality offer a promising explanation of patterns in extrapair fertilizations among bird species.     

Agricultural drainage and wetland management in Ontario

Land drainage is recognized as an integral part of agricultural activity throughout the world. However, the increase in agricultural production has resulted in the loss of wetland functions and values. Therefore, wetland management and agricultural drainage illustrate the conflict between economic development and natural values. This research assesses the approval process for agricultural land drainage in Ontario, Canada, to determine how the benefits of increased agricultural production are balanced against the loss of wetland values. A permit review of drainage applications was conducted from 1978 to 1997 in Zorra Township, Ontario, Canada. Data collection also included the document reviews, interviews with government agencies and wetland evaluation files. The selected criteria include efficiency, equity, consistency and adequacy. The results indicate that while the process is efficient, fundamental problems remain with the bargaining process.     

Multispecies and Multiscale Conservation Planning: Setting Quantitative Targets for Red‐Listed Lichens on Ancient Oaks

Abstract: Species occurrence in a habitat patch depends on local habitat and the amount of that habitat in the wider landscape. We used predictions from empirical landscape studies to set quantitative conservation criteria and targets in a multispecies and multiscale conservation planning effort. We used regression analyses to compare species richness and occurrence of five red‐listed lichens on 50 ancient oaks (Quercus robur; 120–140 cm in diameter) with the density of ancient oaks in circles of varying radius from each individual oak. Species richness and the occurrence of three of the five species were best explained by increasing density of oaks within 0.5 km; one species was best explained by the density of oaks within 2 km, and another was best predicted by the density of oaks within 5 km. The minimum numbers of ancient oaks required for “successful conservation” was defined as the number of oaks required to obtain a predicted local occurrence of 50% for all species included or a predicted local occurrence of 80% for all species included. These numbers of oaks were calculated for two relevant landscape scales (1 km² and 13 km²) that corresponded to various species responses, in such a way that calculations also accounted for local number of oaks. Ten and seven of the 50 ancient oaks surveyed were situated in landscapes that already fulfilled criteria for successful conservation when the 50% and 80% criteria, respectively, were used to define the level of successful conservation. For cost‐efficient conservation, oak stands in the landscapes most suitable for successful conservation should be prioritized for conservation and management (e.g., grazing and planting of new oaks) at the expense of oak stands situated elsewhere.     

Do stress hormones suppress helper reproduction in the cooperatively breeding red-cockaded woodpecker (<Emphasis Type="Italic">Picoides borealis</Emphasis>)?

In the cooperatively breeding red-cockaded woodpecker (Picoides borealis), male helpers are subordinate to male breeders and do not mate with females, even when unrelated to the breeding female within their group or through extra-group matings, yet exhibit reproductive hormone profiles similar to those of breeders. We investigated whether reproduction might be suppressed in helper males via high levels of the stress hormone corticosterone. We also examined effects of group size and season on corticosterone levels by comparing baseline and maximal plasma levels of corticosterone between helper males and breeding males, and among helper males and breeders of both sexes living in groups of different sizes throughout the reproductive cycle. We also measured plasma levels of estrogen, progesterone, and testosterone to examine other potential hormonal differences between helpers and breeders. Male status did not explain variation in any hormones; therefore, our data do not support the hypothesis that helper males are reproductively suppressed via corticosterone or the other hormones investigated. However, the presence of two or more helper males in a group tended to reduce baseline corticosterone in breeding and helper males, but not breeding females, suggesting that helper males reduce parental effort of other male group members. Seasonally, maximal corticosterone peaked during the nestling provisioning phase for breeding and helper males, but not breeder females, suggesting that males show an increased response to stressors posing a potential threat to survival of offspring.     

Helpers and egg investment in the cooperatively breeding acorn woodpecker: testing the concealed helper effects hypothesis

In cooperatively breeding acorn woodpeckers (Melanerpes formicivorus), helper males have a large positive effect on fledging success in good acorn crop years but only a small positive effect in poor acorn crop years, while helper females exhibit the opposite pattern. Based on these findings, we tested the “concealed helper effects” hypothesis, which proposes that laying females reduce investment in eggs (with respect to their size, number, or quality) in a way that confounds helper effects and results in an absence of a relationship between helpers and breeding success. Results generally failed to support the hypothesis. Mean egg size was positively related to temperatures during the 10 days prior to egg-laying and negatively related to the food supply as indexed by the prior fall’s acorn crop, but there were no significant differences vis-à-vis helpers except for interactions with the acorn crop that only partly corresponded to those predicted. With respect to clutch size, females laid larger clutches when assisted by female helpers, opposite the pattern predicted. Although our results suggest that egg size is adjusted to particular ecological circumstances, we conclude that neither egg nor clutch size is adjusted in a way that confounds the apparent effects of helpers, as proposed by the concealed helper effects hypothesis.