ALBERT

Description: Using field experiments, we investigated the responses of bats to street lights with different emission spectra. Fast‐flying species are attracted to orange, white and green light, while slower‐flying species are deterred. The threatened lesser horseshoe bat Rhinolophus hipposideros is also deterred by red light, challenging a previously held assumption that red light is safe for bats. Using radio tracking, we demonstrate that the impact of lights on R. hipposideros can be mitigated by controlling light spill along preferred commuting routes. We argue it is essential to preserve dark corridors to mitigate the impacts of light pollution on bats. Abstract The rapid global spread of artificial light at night is causing unprecedented disruption to ecosystems. In otherwise dark environments, street lights restrict the use of major flight routes by some bats, including the threatened lesser horseshoe bat Rhinolophus hipposideros, and may disrupt foraging. Using radio tracking, we examined the response of individual female R. hipposideros to experimental street lights placed on hedgerows used as major flight routes. Hedgerows were illuminated on one side over four nights using lights with different emission spectra, while the opposite side of the hedge was not illuminated. Automated bat detectors were used to examine changes in overall bat activity by R. hipposideros and other bat species present. R. hipposideros activity reduced significantly under all light types, including red light, challenging a previously held assumption that red light is safe for bats. Despite this, R. hipposideros rapidly adapted to the presence of lights by switching their flight paths to the dark side of the hedgerow, enabling them to reach foraging sites without restriction. Red light had no effect on the activity of the other species present. Slow‐flying Myotis spp. avoided orange, white and green light, while more agile Pipistrellus spp. were significantly more active at these light types compared to dark controls, most probably in response to accumulations of insect prey. No effect of any light type was found for Nyctalus or Eptesicus spp. Our findings demonstrate that caution must be used when promoting forms of lighting that are thought to be safe for wildlife before they are tested more widely. We argue that it is essential to preserve dark corridors to mitigate the impacts of artificial light at night on bat activity and movements.

Description: Global increases in the occurrence of large, severe wildfires in forested watersheds threaten drinking water supplies and aquatic ecology. Wildfire effects on water quality, particularly nutrient levels and forms, can be significant. The longevity and downstream propagation of these effects, as well as the geochemical mechanisms regulating them remain largely undocumented at larger river basin scales. Here, phosphorus (P) speciation and sorption behavior of suspended sediment were examined in two river basins impacted by a severe wildfire in southern Alberta, Canada. Fine grained suspended sediments (〈125 μm) were sampled continuously during ice-free conditions over a two year period (2009-2010), 6 and 7 years after the wildfire. Suspended sediment samples were collected from upstream reference (unburned) river reaches, multiple tributaries within the burned areas, and from reaches downstream of the burned areas, in the Crowsnest and Castle River basins. Total particulate phosphorus [TPP], particulate phosphorus [PP] forms (non-apatite inorganic P [NAIP], apatite P [AP], organic P [OP]), and the equilibrium phosphorus concentration (EPC 0 ) of suspended sediment were assessed. Concentrations of TPP and the EPC 0 were significantly higher downstream of wildfire-impacted areas compared to reference (unburned) upstream river reaches. Sediments from the burned tributary inputs contained higher levels of bioavailable particulate P (NAIP)—these effects were also observed downstream at larger river basin scales. The release of bioavailable P from post-fire, P-enriched fine sediment is a key mechanism causing these effects in gravel-bed rivers at larger basin scales. Wildfire-associated increases in NAIP and the EPC 0 persisted 6 and 7 years after wildfire. Accordingly, this work demonstrated that fine sediment in gravel-bed rivers is a significant, long-term source of in-stream bioavailable P that contributes to a legacy of wildfire impacts on downstream water quality, aquatic ecology, and drinking water treatability. This article is protected by copyright. All rights reserved.

Description: Climate change is likely to have major impacts on the distribution of planted and natural forests. Here we demonstrate how a process-based niche model (CLIMEX) can be extended to project globally the potential habitat suitable for Douglas-fir. Within this distribution we use CLIMEX to predict abundance of the pathogen P haeocryptopus gaeumannii and severity of its associated foliage disease, Swiss needle cast. The distribution and severity of the disease, which can strongly reduce growth rate of Douglas-fir, is closely correlated with seasonal temperatures and precipitation. This model is used to project how climate change during the 2080s may alter the area suitable for Douglas-fir plantations within New Zealand. The climate change scenarios used indicate that the land area suitable for Douglas-fir production in the North Island will be reduced markedly from near 100% under current climate to 36 – 64% of the total land area by 2080's. Within areas shown to be suitable for the host in the North Island, four of the six climate change scenarios predict substantial increases in disease severity that will make these regions at best marginal for Douglas-fir by the 2080's. In contrast, most regions in the South Island are projected to sustain relatively low levels of disease, and remain suitable for Douglas-fir under climate change over the course of this century.

Description: Decomposition of soil organic matter (SOM) is mediated by microbial extracellular hydrolytic enzymes (EHEs). Thus, given the large amount of carbon (C) stored as SOM, it is imperative to understand how microbial EHEs will respond to global change (and warming in particular) to better predict the links between SOM and the global C cycle. Here, we measured the Michaelis-Menten kinetics [maximal rate of velocity ( V max ) and half-saturation constant ( K m )] of five hydrolytic enzymes involved in SOM degradation (cellobiohydrolase, β-glucosidase, β-xylosidase, α-glucosidase, and N-acetyl-β- d -glucosaminidase) in five sites spanning a boreal forest to a tropical rainforest. We tested the specific hypothesis that enzymes from higher latitudes would show greater temperature sensitivities than those from lower latitudes. We then used our data to parameterize a mathematical model to test the relative roles of V max and K m temperature sensitivities in SOM decomposition. We found that both V max and K m were temperature sensitive, with Q 10 values ranging from 1.53 to 2.27 for V max and 0.90-1.57 for K m . The Q 10 values for the K m of the cellulose-degrading enzyme β-glucosidase showed a significant (P=0.004) negative relationship with mean annual temperature, indicating that enzymes from cooler climates can indeed be more sensitive to temperature. Our model showed that K m temperature sensitivity can offset SOM losses due to V max temperature sensitivity, but the offset depends on the size of the SOM pool and the magnitude of V max . Overall, our results suggest that there is local adaptation of microbial EHE kinetics to temperature and that this should be taken into account when making predictions about the responses of C cycling to global change.

Description: Artificial lighting is a key biodiversity threat and produces 1900 million tonnes of CO 2 emissions globally, more than three times that produced by aviation. The need to meet climate change targets has led to a global increase in energy-efficient light sources such as high-brightness light-emitting diodes (LEDs). Despite the energetic benefits of LEDs, their ecological impacts have not been tested. Using an experimental approach we show that LED street lights caused a reduction in activity of slow-flying bats ( Rhinolophus hipposideros and Myotis spp.). Both R. hipposideros and Myotis spp. activity was significantly reduced even during low light levels of 3.6 lux. There was no effect of LED lighting on the relatively fast-flying Pipistrellus pipistrellus , P. pygmaeus and Nyctalus/Eptesicus spp. We provide the first evidence of the effects of LED lights on bats. Despite having considerable energy-saving benefits, LED lights can potentially fragment commuting routes for bats with associated negative conservation consequences. Our results add to the growing evidence of negative impacts of lighting on a wide range of taxa. We highlight the complexities involved in simultaneously meeting targets for reduction of greenhouse gas emissions and biodiversity loss. New lighting strategies should integrate climate change targets with the cultural, social, and ecological impacts of emerging lighting technologies.

Description: Artificial lighting is a key biodiversity threat and produces 1900 million tonnes of CO 2 emissions globally, more than three times that produced by aviation. The need to meet climate change targets has led to a global increase in energy-efficient light sources such as high-brightness light-emitting diodes (LEDs). Despite the energetic benefits of LEDs, their ecological impacts have not been tested. Using an experimental approach we show that LED street lights caused a reduction in activity of slow-flying bats ( Rhinolophus hipposideros and Myotis spp.). Both R. hipposideros and Myotis spp. activity was significantly reduced even during low light levels of 3.6 lux. There was no effect of LED lighting on the relatively fast-flying Pipistrellus pipistrellus , P. pygmaeus and Nyctalus/Eptesicus spp. We provide the first evidence of the effects of LED lights on bats. Despite having considerable energy-saving benefits, LED lights can potentially fragment commuting routes for bats with associated negative conservation consequences. Our results add to the growing evidence of negative impacts of lighting on a wide range of taxa. We highlight the complexities involved in simultaneously meeting targets for reduction of greenhouse gas emissions and biodiversity loss. New lighting strategies should integrate climate change targets with the cultural, social, and ecological impacts of emerging lighting technologies.

Description: Soil microbes produce extracellular enzymes that degrade carbon (C)-containing polymers in soil organic matter. Because extracellular enzyme activities may be sensitive to both increased nitrogen (N) and temperature change, we measured the effect of long-term N addition and short-term temperature variation on enzyme kinetics in soils from hardwood forests at Bear Brook, Maine, and Fernow Forest, West Virginia. We determined the V max and K m parameters for five hydrolytic enzymes: α-glucosidase, β-glucosidase, β-xylosidase, cellobiohydrolase, and N -acetyl-glucosaminidase. Temperature sensitivities of V max and K m were assessed within soil samples subjected to a range of temperatures. We hypothesized that 1) N additions would cause microbial C limitation, leading to higher enzyme V max values and lower K m values; and 2) both V max and K m would increase at higher temperatures. Finally, we tested whether temperature sensitivity of enzyme kinetics is mediated by N addition. Nitrogen addition significantly or marginally significantly increased V max values for all enzymes, particularly at Fernow. Nitrogen fertilization led to significantly lower K m values for all enzymes at Bear Brook, but variable K m responses at Fernow Forest. Both V max and K m were temperature sensitive, with Q 10 values ranging from 1.64-2.27 for enzyme V max and 1.04-1.93 for enzyme K m . No enzyme showed a significant interaction between N and temperature sensitivity for V max , and only β-xylosidase showed a significant interaction between N and temperature sensitivity for K m . Our study is the first to experimentally demonstrate a positive relationship between K m and temperature for soil enzymes. Higher temperature sensitivities for V max relative to K m imply that substrate degradation will increase with temperature. Additionally, the V max and K m responses to N indicate greater substrate degradation under N addition. Our results suggest that increasing temperatures and N availability in forests of the northeastern US will lead to increased hydrolytic enzyme activity, despite the positive temperature sensitivity of K m .

Description: We examined the hypothesis that climate‐driven evolution of plant traits will influence associated soil microbiomes and ecosystem function across the landscape. We show that (a) as mean annual temperature (MAT) increases, genetic and phenotypic variation for bud break phenology decline; (b) soil microbiomes, soil nitrogen (N), and soil carbon (C) vary in response to MAT and conditioning by trees; and (c) with losses of genetic variation due to warming, population‐level regulation of community and ecosystem functions strengthen. These results demonstrate a relationship between the potential evolutionary response of populations and subsequent shifts in ecosystem function along a large temperature gradient. Abstract We examined the hypothesis that climate‐driven evolution of plant traits will influence associated soil microbiomes and ecosystem function across the landscape. Using a foundation tree species, Populus angustifolia, observational and common garden approaches, and a base population genetic collection that spans 17 river systems in the western United States, from AZ to MT, we show that (a) as mean annual temperature (MAT) increases, genetic and phenotypic variation for bud break phenology decline; (b) soil microbiomes, soil nitrogen (N), and soil carbon (C) vary in response to MAT and conditioning by trees; and (c) with losses of genetic variation due to warming, population‐level regulation of community and ecosystem functions strengthen. These results demonstrate a relationship between the potential evolutionary response of populations and subsequent shifts in ecosystem function along a large temperature gradient.