Suchergebnisse

Context Ungulate life-history strategies and behaviour are driven by two dominant factors, namely, acquisition of nutrients and avoidance of predation. Although many studies have investigated single species resource/habitat selection, there are still gaps in our understanding of multi-species systems and resource partitioning. Aim We explored the habitat selection of five sympatric resident ungulates in relation to seasonal phenological gradients in a temperate grassland (Northern Great Plains) system. We identified and compared habitat-utilisation strategies across the vegetation-growing season and related to established forage acquisition hypotheses. Methods We collected ungulate detection data during two field seasons (July–October 2018, May–September 2019) across 202 sites and deployed 1202 cameras (29 284 camera-nights). We modelled ungulate detections in relation to normalised difference vegetation index (NDVI) and NDVI slope (rate and direction of change) to learn about ungulate resource selection in four habitat types (grass, prairie dog colonies, forest and riparian). Results We found unique foraging strategies for each of the focal species throughout the growing season (spring, summer, early autumn), which resulted in seasonal partitioning of resources among sympatric ungulate species. Conclusions The temporal and spatial patterns observed emphasise that multiple species can experience the same vegetation phenology and respond differently in their movements and foraging behaviour. At local scales, some ungulates selected for higher forage quantity (selection of higher NDVI) and some for higher forage quality (selection of positive NDVI slope or greening up). Implications The unique foraging strategies presented here indicated that generalisations are problematic when managing wildlife resources and emphasise the need to conduct multi-species studies to understand resource utilisation at local scales. Furthermore, understanding variation in foraging strategies of resident sympatric species can direct management planning where decreased connectivity or loss of migration pathways alters traditional behaviours.

Monitoring the phenological responses of deciduous forests to climate is important, due to the increasing frequency and intensity of extreme climatic events associated with climate change and global warming, which will in turn affect vegetation seasonality. We investigated the spatiotemporal patterns of the response of deciduous forests to climatic anomalies in the Northern Hemisphere, using satellite-derived phenological metrics from the Copernicus Global Land Service Leaf Area Index, and multisource climatic datasets for 2000–2018 at resolutions of 0.1◦. Thereafter, we assessed the impact of extreme heatwaves and droughts on this deciduous forest phenology. We assumed that changes in the deciduous forest phenology in the Northern Hemisphere for the period 2000–2018 were monotonic, and that temperature and precipitation were the main climatic drivers. Analyses of partial correlations of phenological metrics with the timing of the start of the season (SoS), end of the season (EoS), and climatic variables indicated that changes in preseason temperature played a stronger role than precipitation in affecting the interannual variability of SoS anomalies: the higher the temperature, the earlier the SoS in most deciduous forests in the Northern Hemisphere (mean correlation coefficient of −0.31). Correlations between the SoS and temperature were significantly negative in 57% of the forests, and significantly positive in 15% of the forests (p 20 d in response to heatwaves throughout most of Europe in 2003, and in the United States of America in 2012. This study contributes to improve our understanding of the phenological responses of deciduous forests in the Northern Hemisphere to climate change and extreme climate events. ; his research was supported by an FPU (Formación del Profesorado Universitario) grant from the Spanish Ministry of Education and Professional Training to the first author (FPU2015-04798), as well as grants from the Copernicus Global Land Service (CGLOPS-1-199494-JRC), the Spanish Government grant PID2019-110521GB-I00, the Fundación Areces grant ELEMENTAL-CLIMATE, the Catalan Government grant SGR 2017–1005, and the European Research Council Synergy grant ERC-2013-SyG-610028 IMBALANCE-P. ; Peer reviewed

Abstract
Pesticide use is well known to be detrimental for maintaining biodiversity in the agricultural landscape. Amphibians are especially affected by these agrochemicals. In particular, these animals' high sensitivity was demonstrated for glyphosate-based herbicides which are dominating the world market today. Pesticide impacts are influenced by several co-stressors, and we for the first time link the exposure risk of amphibians to these commonly used pesticides to observed recent effects from ongoing climate change. In a simple verbal model, based on present-day data from Germany, we show that amphibian populations which have undergone phenological shift towards earlier reproduction potentially suffer less from applications of glyphosate-based herbicides compared to those which (yet) show no such reproductive shift. Although, apparently observed recent climate change effects lower the exposure risk, we advocate that amphibians are not necessarily safer now, mainly because farmers most likely will adapt their cultivation practices in the future if climate change becomes more obvious. Rather, we conclude that combining pesticide applications, climate change and phenological responses need an increased consideration in amphibian conservation. The results from our verbal model should be seen as a hypothesis that needs to be tested with specific field studies and (based on these data which are widely lacking today) more complex modelling of future exposure risk of pesticides to amphibians.

Understanding the spatio-temporal dynamics of land surface phenology is important to understanding changes in landscape ecological processes of semi-arid savannas in Southern Africa. The aim of the study was to determine the influence of variation in tree cover percentage on land surface phenological response in the semi-arid savanna of Southern Africa. Various land surface phenological metrics for the green-up and senescing periods of the vegetation were retrieved from leaf index area (LAI) seasonal time series (2001 to 2015) maps for a study region in South Africa. Tree cover (%) data for 100 randomly selected polygons grouped into three tree cover classes, low (40%, n = 34), were used to determine the influence of varying tree cover (%) on the phenological metrics by means of the t-test. The differences in the means between tree cover classes were statistically significant (t-test p < 0.05) for the senescence period metrics but not for the green-up period metrics. The categorical data results were supported by regression results involving tree cover and the various phenological metrics, where tree cover (%) explained 40% of the variance in day of the year at end of growing season compared to 3% for the start of the growing season. An analysis of the impact of rainfall on the land surface phenological metrics showed that rainfall influences the green-up period metrics but not the senescence period metrics. Quantifying the contribution of tree cover to the day of the year at end of growing season could be important in the assessment of the spatial variability of a savanna ecological process such as the risk of fire spread with time. ; The Council for Industrial and Scientific Research (CSIR) Parliamentary Grant, Southern African Science Service Centre for Climate Change and Adaptive Land Management (SASSCAL) and ECOPOTENTIAL project which received funding from the European Union's Horizon 2020 Research and Innovation Programme under grant agreement No. ...

Intro -- Preface -- Contents -- Chapter 1: Influences of Climate Change on the Distribution and Population Dynamics of Subalpine Coniferous Forest in the Hakk... -- 1.1 Introduction -- 1.2 Climate and Vegetation in the Hakkoda Mountains -- 1.3 Population Dynamics of Subalpine Coniferous Trees in Recent Decades -- 1.4 Predicted Distribution Shift of the Subalpine Forest -- 1.5 Conclusions -- References -- Chapter 2: Trait-Based Approaches for Understanding Species Niche, Coexistence, and Functional Diversity in Subalpine Moorlands -- 2.1 Introduction -- 2.2 Functional Classification and Trait-Based Approach -- 2.3 Characteristics of Moorland Plant Communities -- 2.4 Case Studies of Moorland in the Hakkoda Mountain Range -- 2.4.1 Study Site -- 2.4.2 Plant Species Diversity in Moorlands -- 2.4.3 Community Ecology of Functional Traits: Variations in Functional Traits Within and Among Moorland Plant Communities -- 2.4.4 The Ecophysiological Approach: How Do Functional Traits Contribute to the Coexistence and Replacement of Species? -- 2.4.5 Vulnerability Assessment of Moorland Plant Communities -- 2.5 Conclusions -- References -- Chapter 3: Landscape Structure of Flowering Phenology in Alpine Ecosystems: Significance of Plant-Pollinator Interactions and ... -- 3.1 Introduction -- 3.2 Phenological Responses of Alpine Plants to the Abiotic Environment -- 3.2.1 Temperature Dependence and Snowmelt Regime -- 3.2.2 Landscape Structure of Flowering Phenology -- 3.3 Pollination Syndrome of Flowering Phenology -- 3.3.1 Pollinator Types for Alpine Plants -- 3.3.2 Seasonal Activity of Bees and Flies -- 3.3.3 Flowering Pattern of Bee-Pollinated and Fly-Pollinated Plants -- 3.4 Phenological Matching of Flowers and Pollinators -- 3.4.1 Phenological Shift in Response to Climate Change -- 3.4.2 Phenological Mismatch Between Alpine Plants and Bumblebees.

Biological nitrogen fixation (BNF) is an alternative for the supply of N, aiming at reducing production costs and environmental impacts of common bean crops. This work aimed to evaluate the agroeconomic performance of the inoculated common bean subjected to N-fertilizer application at different phenological phases. N-fertilizer, in a total of 90 kg ha-1 as urea, was applied at 3 phases: planting (P), phenological phase V4 (V4), and phenological phase R5 (R5) of the common bean, in two field experiments. The used treatments were: P0V40R50, P0V445R545, P0V490R50, P0V40R590, P30V430R530, P30V460R50, P30V40R560, P60V430R50, P60V40R530, and P90V40R50. All treatments were inoculated with peat inoculum containing the commercial strain SEMIA 4077 (Rhizobium tropici). The number of nodules (NN), nodule dry mass (NDM), leaf area index (LAI), root dry mass (RDM), shoot dry mass (SDM), grain yield (GY), production cost (PC), gross revenue (GR), net revenue (NR), and benefit-cost ratio (BCR) were determined. Inoculated treatment (P0V40R50) showed higher NN and NDM. Although inoculated treatment (P0V40R50) showed lower values of LAI, RDM, SDM, and GY, inoculation can result in GR, NR, and BCR equal to N-fertilized treatments, depending on the prices achieved for grains sale.

The phenological responses of plants to changing weather conditions are very strong and can serve as an indicator of global climate change. If we understand how individual species respond to changing conditions, we can represent how ecosystems will change. The aim of this study was to analyze the exposure of climatic factors (air temperature and precipitation) on the fl owering duration of the wild vascular plants species in the Karadag Nature Reserve (Crimea). In general, 152 species were taken into account with a number of phenological observations from 5 to 8 years. Correlation analysis between the fl owering duration and the climatic parameters revealed a signifi cant response in 89 (58.6%) species. Moreover, the climatic factors of the current vegetative season impacted 71 species fl owering, previous vegetative season impacted 4 species fl owering, and both vegetative seasons impacted 14 species fl owering. Air temperature and precipitation equally impacted the fl owering duration: air temperature impacted 35 (41.2%) species fl owering; precipitation impacted 32 (37.7%) species fl owering; both factors impacted 18 (21.1%) species flowering. The flowering duration mostly was negatively correlated with air temperature values and positively with precipitation amount. Mesophytes and the forest community species were the most sensitive to the climatic factors; euxerophytes and the steppe community species were the least sensitive to the climatic factors.

It is well known that the timing of growth and development influences critical life stages of all organisms. The seasonal dynamics of ecosystems are usually well explained by photoperiod and temperature. However, phenological patterns in water-limited ecosystems are rarely studied and insufficiently explained by these two variables. We tested how onset (i.e., initiation of plant growth) and seasonality of plant growth are influenced by soil temperature and soil water. We collected seven years of daily measurements of near-surface reflected radiation, soil moisture, and soil temperature at an exclosure on the Shortgrass Steppe Long-Term Ecological Research Site, a semiarid ecosystem in the western Great Plains of the United States. We determined that soil water content must be close to field capacity and soil temperature must be above 0°C to initiate a phenological response. We show for the first time that onset of spring and subsequent seasonal patterns of plant growth depend on both soil temperature and soil moisture. Our findings bear important implications for understanding responses of the shortgrass steppe and other semiarid ecosystems to climate change. Inadequate combinations of degree days and soil water may result from future precipitation and temperature, which are predicted to diverge from current patterns. Historical expectations about spring green-up, for example, for land and livestock management, seasonality of growth, and productivity, may fail and can only be replaced by taking both precipitation and temperature into account.

Inferring species' responses to climate change in the absence of long-term time series data is a challenge, but can be achieved by substituting space for time. For example, thermal elevational gradients represent suitable proxies to study phenological responses to warming. We used butterfly data from two Mediterranean mountain areas to test whether mean dates of appearance of communities and individual species show a delay with increasing altitude, and an accompanying shortening in the duration of flight periods. We found a 14-day delay in the mean date of appearance per kilometer increase in altitude for butterfly communities overall, and an average 23-day shift for 26 selected species, alongside average summer temperature lapse rates of 3°C per km. At higher elevations, there was a shortening of the flight period for the community of 3 days/km, with an 8.8-day average decline per km for individual species. Rates of phenological delay differed significantly between the two mountain ranges, although this did not seem to result from the respective temperature lapse rates. These results suggest that climate warming could lead to advanced and length-ened flight periods for Mediterranean mountain butterfly communities. However, although multivoltine species showed the expected response of delayed and short-ened flight periods at higher elevations, univoltine species showed more pronounced delays in terms of species appearance. Hence, while projections of overall community responses to climate change may benefit from space-for-time substitutions, under-standing species-specific responses to local features of habitat and climate may be needed to accurately predict the effects of climate change on phenology. ; This research has been cofinanced by the European Union (European Social Fund ESF) and Greek National Funds through the Operational Program "Education and Lifelong Learning" of the National Strategic Reference Framework (NSRF)—Research Funding Program: Heracleitus II. Investing in knowledge society through the European Social Fund. ; Peer reviewed

A set of ten RADARSAT-2 images acquired in fully polarimetric mode over a test site with rice fields in Seville, Spain, has been analyzed to extract the main features of the C-band radar backscatter as a function of rice phenology. After observing the evolutions versus phenology of different polarimetric observables and explaining their behavior in terms of scattering mechanisms present in the scene, a simple retrieval approach has been proposed. This algorithm is based on three polarimetric observables and provides estimates from a set of four relevant intervals of phenological stages. The validation against ground data, carried out at parcel level for a set of six stands and up to nine dates per stand, provides a 96% rate of coincidence. Moreover, an equivalent compact-pol retrieval algorithm has been also proposed and validated, providing the same performance at parcel level. In all cases, the inversion is carried out by exploiting a single satellite acquisition, without any other auxiliary information. ; This work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO) and European Union FEDER under Project TEC2011-28201-C02-02.