On the importance of non-linear relationships between landscape patterns and the sustainable provision of ecosystem services

Marginal land use changes can abruptly result in non-marginal and irreversible changes in ecosystem functioning and the economic values that the ecosystem generates. This challenges the traditional ecosystem services (ESS) mapping approach, which has often made the assumption that ESS can be mapped uniquely to land use and land cover data. Using a functional fragmentation measure, we show how landscape pattern changes might lead to changes in the delivery of ESS. We map changes in ESS of dry calcareous grasslands under different land use change scenarios in a case study region in Switzerland. We selected three ESS known to be related to species diversity including carbon sequestration and pollination as regulating values and recreational experience as cultural value, and compared them to the value of two production services including food and timber production. Results show that the current unceasing fragmentation is particularly critical for the value of ESS provided by species-rich habitats. The article concludes that assessing landscape patterns is key for maintaining valuable ESS in the face of human use and fluctuating environment.     

Ethylene production throughout growth and development of plants

Ethylene production by 10 or 20 m2 stands of wheat, soybean, lettuce, potato, and tomato was monitored throughout growth and development in an atmospherically closed plant chamber. Chamber ethylene levels varied among species and rose during periods of canopy expansion and rapid growth for all species. Following this, ethylene levels either declined during seed fill and maturation for wheat and soybean, or remained relatively constant for potato and tomato (during flowering and early fruit development). Lettuce plants were harvested during rapid growth and peak ethylene production. Chamber ethylene levels increased rapidly during tomato ripening, reaching concentrations about 10 times that measured during vegetative growth. The highest ethylene production rates during vegetative growth ranged from 1.6 to 2.5 nmol m-2 d-1 during rapid growth of lettuce and wheat stands, or about 0.3 to 0.5 nmol g-1 fresh weight per hour. Estimates of stand ethylene production during tomato ripening showed that rates reached 43 nmol m-2 d-1 in one study and 93 nmol m-2 d-1 in a second study with higher lighting, or about 50x that of the rate during vegetative growth of tomato. In a related test with potato, the photoperiod was extended from 12 to 24 hours (continuous light) at 58 days after planting (to increase tuber yield), but this change in the environment caused a sharp increase in ethylene production from the basal rate of 0.4 to 6.2 nmol m-2 d-1. Following this, the photoperiod was changed back to 12 h at 61 days and ethylene levels decreased. The results suggest three separate categories of ethylene production were observed with whole stands of plants: 1) production during rapid vegetative growth, 2) production during climacteric fruit ripening, and 3) production from environmental stress.     

Effects of sensor spatial resolution on landscape structure parameters

We examined the effects of increasing grain size from 20 m to 1100 m on landscape parameters characterizing spatial structure in the northern Wisconsin lake district. We examined whether structural parameters remain relatively constant over this range and whether aggregation algorithms permit extrapolation within this range. Images from three different satellite sensors were employed in this study: (1) the SPOT multispectral high resolution visible (HRV), (2) the Landsat Thematic Mapper (TM), and (3) the NOAA Advanced Very High Resolution Radiometer (AVHRR). Each scene was classified as patches of water in a matrix of land. Spatial structure was quantified using several landscape parameters: percent water, number of lakes (patches), average lake area and perimeter, fractal dimension, and three measures of texture (homogeneity, contrast, and entropy). Results indicate that most measures were sensitive to changes in grain size. As grain size increased from 20 m using HRV image data to 1100 m (AVHRR), the percent water and the number of lakes decreased while the average lake area, perimeter, the fractal dimension, and contrast increased. The other two texture measures were relatively invariant with grain size. Although examination of texture at various angles of adjacency was performed to investigate features which vary systematically with angle, the angle did not have an important effect on the texture parameter values. An aggregation algorithm was used to simulate additional grain sizes. Grain was increased successively by a factor of two from 20 m (the HRV image) to 1280 m. We then calculated landscape parameter values at each grain size. Extrapolated values closely approximated the actual sensor values. Because the grain size has an important effect on most landscape parameters, the choice of satellite sensor must be appropriate for the research question asked. Interpolation between the grain sizes of different satellite sensors is possible with an approach involving aggregation of pixels.     

Analysis and cytologic characterization of hemocytes from freshwater mussels (Quadrula sp.)

Background: Freshwater mussels are among the most endangered taxa in North America and minimally invasive techniques to evaluate their health are needed. Objective: The objective of this study was to develop a standardized approach for identifying and enumerating the cellular components of freshwater mussel hemolymph. Methods: Hemocyte clumping, total hemocyte count, and hemocyte morphology were compared in untreated hemolymph or hemolymph treated with formalin, sodium citrate, sodium heparin, EDTA, water, or l ‐cysteine. Morphology was then used to categorize hemocytes and perform a 100‐cell differential. Results: Treatment with formalin or >25 mg/mL l ‐cysteine reduced hemocyte clumping, although only formalin significantly increased the total hemocyte count. However, formalin also induced crenation that impaired hemocyte identification. Both EDTA and sodium citrate‐induced hemocyte degranulation while sodium citrate and >40 mg/mL l ‐cysteine‐induced cell lysis. Hemocytes could be categorized into 2 groups of granulocytes (eosinophilic or basophilic) and 2 groups of agranulocytes (large or small) for performing a cytologic differential. The differential was not significantly altered by anticoagulant treatments providing cell morphology was adequate for obtaining a differential. Eosinophilic granulocytes predominated (59%) with fewer large agranulocytes (27%) and basophilic granulocytes (13%). Small agranulocytes comprised 2% of the total population. Conclusions: No single treatment provided an optimal method to evaluate freshwater mussel hemolymph. Maximal hemocyte counts were obtained following formalin treatment. l ‐cysteine reduced clumping and maintained hemocyte morphology for performing a cytologic differential. These techniques provide a standardized approach for the hematologic evaluation of freshwater mussels.     

Connecting phenological predictions with population growth rates for mountain pine beetle,an outbreak insect

It is expected that a significant impact of global warming will be disruption of phenology as environmental cues become disassociated from their selective impacts. However there are few, if any, models directly connecting phenology with population growth rates. In this paper we discuss connecting a distributional model describing mountain pine beetle phenology with a model of population success measured using annual growth rates derived from aerially detected counts of infested trees. This model bridges the gap between phenology predictions and population viability/growth rates for mountain pine beetle. The model is parameterized and compared with 8 years of data from a recent outbreak in central Idaho, and is driven using measured tree phloem temperatures from north and south bole aspects and cumulative forest area impacted. A model driven by observed south-side phloem temperatures and that includes a correction for forest area previously infested and killed is most predictive and generates realistic parameter values of mountain pine beetle fecundity and population growth. Given that observed phloem temperatures are not always available, we explore a variety of methods for using daily maximum and minimum ambient temperatures in model predictions.     

Modelling multi-species response to landscape dynamics: mosaic cycles support urban biodiversity

The importance of the spatial as well as the temporal structure of habitat patches for urban biodiversity has been recognised, but rarely quantified. In dynamic environments the rate of habitat destruction and recreation (i.e. the landscape turnover rate), the minimum amount of potential habitat, its spatial configuration as well as the environmental conditions determining habitat quality are crucial factors for species occurrence. We analysed species responses to environmental parameters and to the spatio-temporal configuration of urban brownfield habitats in a multi-species approach (37 plant and 43 insect species). Species presence/absence data and soil parameters, site age, vegetation structure and landscape context were recorded by random stratified sampling at 133 study plots in industrial areas in the city of Bremen (Germany). Based on the field data, we predicted species occurrences by species distribution models using a multi-model inference approach. Predicted species communities were driven by successional age both at the scale of a single building lot and at the landscape scale. Minimum average succession time of brownfield habitats required to support all and especially regionally rare species depended on the proportion of available open space; the larger the potential habitat area the faster the acceptable turnover. Most plant, grasshopper, and leafhopper species modelled could be maintained at an intermediate turnover rate (mean age of 10–15 years) and a proportion of open sites of at least 40%. Our modelling approach provides the opportunity of inferring optimal spatio-temporal landscape configurations for urban conservation management from patch scale species-environment relationships. The results indicate that urban planning should incorporate land use dynamics into the management of urban biodiversity. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Effect of water deficit on Merlot grape tannins and anthocyanins across four seasons

Tannins and anthocyanins impart important sensory attributes and potential health benefits in wine. The effect of water deficits (WDs) on fruit growth, anthocyanins, and skin tannins was investigated in field grown Vitis vinifera L. ‘Merlot’ berries across four seasons (2004, 2005, 2007, and 2008) by imposing deficits from the onset of ripening until maturity. WD reduced berry weight and increased the concentration of anthocyanins all four seasons, and increased the concentration of tannins three of four seasons. Under WD, anthocyanin concentration at harvest (mg/g of berry fresh weight) was 53.0–61.6% greater than in Controls (C), and anthocyanin content (mg/berry) was 28.7–35.3% greater than in C. By contrast, WD increased tannin concentration (mg/g of berry fresh weight) at harvest by 12.6–36.9% compared to C in 2004, 2005, and 2008, and did not influence the concentration in 2007. Tannin content (mg/berry) at harvest was unaffected except in 2004 when it was 25.7% greater than in C. Thus, water deficits consistently increased anthocyanin concentration by increasing content per berry and reducing fruit growth, but increased tannin concentration less and only by reducing fruit growth, except in one year where the tannin content was increased. These results demonstrate that management of vine water deficit during ripening is a much more effective tool to increase anthocyanins than tannins in Merlot grapes.     

In vitro callus-induction in globe artichoke (Cynara cardunculus L. var. scolymus) as a system for the production of caffeoylquinic acids

Summary

Globe artichoke (Cynara cardunculus L. var. scolymus) provides a rich dietary source of bio-active compounds derived from phenylpropanoid metabolism, notably caffeoylquinic acids (CQAs) and flavonoids. Micropropagation techniques have been established for this species, but in vitro cultures have not yet been extended to generate an efficient system for the induction of callus tissue. In this study, we compared more than 100 combinations of media supplements (e.g., phytohormones, absorbers of polyphenols, and inhibitors of polyphenol oxidase), along with various light regimes, and three different genotypes of globe artichoke to define the optimal conditions for callus induction from leaf explants. This led to the elaboration of an in vitro culture protocol which resulted in a high frequency of callus induction after just 1 week in culture. The procedure used leaf explants from virus-free, meristem culturederived plantlets. Quantitative HPLC analysis revealed that, as in globe artichoke leaves, the predominant phenolic esters present in callus were mono- and di-caffeoylquinic acids (diCQA). The concentration of diCQA was three- to five-fold higher in calli than in leaves. The exposure of calli to UV-C light further enhanced the levels of CQAs. In vitro callus culture combined with UV-C irradiation may thus represent a viable production system for diCQA that is suitable for the synthesis of pharmacologically-active compounds.     

Spatial distribution pattern and physical – biological interactions in the larval notothenioid fish assemblages from the Bransfield Strait and adjacent waters

The Bransfield Strait and adjacent waters represent one of the most important areas of larval retention off the Antarctic Peninsula. The species composition of larval fish assemblages has been described in detail in previous surveys carried out in the area, but the role of environmental parameters influencing the spatial distribution of early life stages was poorly known. By applying generalized additive models and multivariate analyses, we evaluated the role of environmental variables in shaping the small‐scale distribution of larval fish and investigated the spatial structure of the larval assemblage. It consisted of a few dominant notothenioid species, such as Champsocephalus gunnari, Lepidonotothen squamifrons, Lepidonotothen larseni, Pleuragramma antarctica and Trematomus scotti, and several other rarely caught species. Sea water temperature, salinity and sampling depth were the most important factors determining the spatial distribution of fish with different relative contributions, together explaining more than 80% of total deviance observed. Species richness was mostly affected by salinity, probably due to the narrow range of salinity preference by the species. Cluster analysis of abundance and presence data identified six and five distinct groups, respectively, each of them with substantial contributions of single or rarely two species. Differences in reproductive strategies of adult populations and spatial distribution of early life stages driven by different larval behaviour in response to environmental factors contribute to maintaining a well‐structured larval fish assemblage, ensuring spatial and food niche partitioning.