Search results for "106"
showing 10 items of 6128 documents
Temporal variations in microclimate cooling induced by urban trees in Mainz, Germany
2016
Abstract Global warming is likely to increase the frequency and magnitude of heat waves. As the urban geometry and material amplifies warming, city dwellers will face an intensification of heat-induced health problems and mortality. Although increased vegetation cover is frequently used in urban planning to mitigate excessive heat, temporal variations, as well as the influence of synoptic weather conditions and surrounding urban geometry on the vegetation cooling effect, are still unclear. In this study, we monitored the transpiration-induced cooling from trees over two summers in five urban settings characterized by varying levels of greenness and urban geometry in the city of Mainz (Germa…
Plasticity of response of tree-ring width of Scots pine provenances to weather extremes in Latvia
2019
Abstract Climatic changes and weather extremes are causing shifts in distribution of tree species, affecting productivity of forests. With the northwards advance of deciduous species in Northern Europe, Scots pine (Pinus sylvestris L.) is predicted to decrease survival and productivity. Nevertheless, Scots pine have adapted to diverse environments, hence selection among its populations could be applied to sustain productivity of stands under changing climate. In this study, sensitivity of tree-ring width of Eastern European provenances of Scots pine differing by field performance (Dippoldiswalde, Eibenstock, Rytel, Gustrow, and Kalsnava) to weather extremes in three trials in Latvia (hemibo…
Decreasing in patch-size of Cystoseira forests reduces the diversity of their associated molluscan assemblage in Mediterranean rocky reefs
2021
Abstract Canopy-forming seaweeds of the genus Cystoseira (Fucales, Phaeophyceae) form diverse and productive habitats along temperate rocky coasts of the Mediterranean Sea. During the last decade, Cystoseira forests have retracted their range considerably due to many interacting environmental, biological and anthropogenic pressures. We investigated how reducing in patch-size of C. montagnei affects their associated molluscan communities at the shallow northwest rocky shores of Palermo (Sicily, Italy). Molluscs were sampled from the fronds of individual thalli, clumps of 3 and 5 thalli of C. montagnei over an annual vegetative cycle (May–September) in two sites within the Marine Protected Ar…
Do environmental diversity approaches lead to improved site selection? A comparison with the multi-species approach
2008
This paper suggests a new approach to select conservation areas cost-effectively according to the concept of complementarity and representation of focal natural features. The suggested environmental diversity (ED) site selection model maximizes ecological diversity, measured via ordination of the chosen taxa communities. Given their fundamental role in ecosystem functioning, vascular plants are chosen as the indicator taxa. We test the ED indicator model by contrasting it to the conventional site selection indicator (MS model), which maximizes the representation of species number in the indicator taxa. We demonstrate that the ED model is more cost-effective than the MS model. More important…
Ecological and climatological signals in tree-ring width and density chronologies along a latitudinal boreal transect
2016
ABSTRACTShifts in the climate sensitivity of trees throughout the twentieth century might indicate climate change effects in the boreal forest ecosystem. We here evaluated such potential changes by analyzing six tree-ring width (TRW) and maximum latewood density (MXD) chronologies from northern, central and southern boreal forests in Finland (60°N–69°N). Besides latitudinal effects, differing micro-sites (lakeshore and inland) were considered to evaluate the influence of ground water access on twentieth-century tree-ring formation and climate sensitivity. Overall, the boreal MXD chronologies appeared less affected by micro-site conditions compared to the TRW chronologies. Along the boreal t…
Climate sensitivity of high- and low-elevation Larix decidua MXD chronologies from the Tatra Mountains
2020
Abstract Maximum latewood density (MXD) measurements from high-elevation/-latitude sites are an important proxy for summer temperature reconstructions. Here, we present 201 MXD series from living larch (Larix decidua Mill.) trees that were growing at around 850 and 1450 m a.s.l. in the Slovakian Tatra Mountains, together with 56 MXD series from historical timbers of the same species and region. We explore the climate signal at the high- and low-elevation sites and assess the effects of varying temperature and precipitation regimes on MXD formation. Ranging from spring temperature to summer precipitation, the elevation-specific climate sensitivity suggests that the MXD measurements from livi…
A combination of dichogamy and herkogamy mediates reproductive success in the desert shrub Zygophyllum fabago
2020
Abstract Zygophyllum fabago is a species within the arid-adapted family Zygophyllaceae. The species is characterized by the co-occurrence of dichogamy and herkogamy. In order to understand the effect of these two complementary anti-selfing mechanisms in reproductive success, we conducted a detailed study of floral biology in Z. fabago. Our results indicated an incomplete separation of the female and male phases which is referred to as partial dichogamy. We found two floral morphs with distinct stigma position: the Central-morph (C-morph) and the Lateral-morph (L-morph). The stigma-stamen distance in the L-morph was significantly larger than in the C-morph in early, mid, and late male stages…
Optimizing management to enhance multifunctionality in a boreal forest landscape
2016
Summary The boreal biome, representing approximately one-third of remaining global forests, provides a number of crucial ecosystem services. A particular challenge in forest ecosystems is to reconcile demand for an increased timber production with provisioning of other ecosystem services and biodiversity. However, there is still little knowledge about how forest management could help solve this challenge. Hence, studies that investigate how to manage forests to reduce trade-offs between ecosystem services and biodiversity are urgently needed to help forest owners and policy makers take informed decisions. We applied seven alternative forest management regimes using a forest growth simulator…
Complex responses of global insect pests to climate warming
2020
Although it is well known that insects are sensitive to temperature, how they will be affected by ongoing global warming remains uncertain because these responses are multifaceted and ecologically complex. We reviewed the effects of climate warming on 31 globally important phytophagous (plant‐eating) insect pests to determine whether general trends in their responses to warming were detectable. We included four response categories (range expansion, life history, population dynamics, and trophic interactions) in this assessment. For the majority of these species, we identified at least one response to warming that affects the severity of the threat they pose as pests. Among these insect spec…
Changes of energy fluxes in marine animal forests of the anthropocene: Factors shaping the future seascape
2019
12 pages, 3 figures