Ecological impacts of a widespread frost event following early spring leaf-out

2012 ◽  
Vol 18 (7) ◽  
pp. 2365-2377 ◽  
Author(s):  
Koen Hufkens ◽  
Mark A. Friedl ◽  
Trevor F. Keenan ◽  
Oliver Sonnentag ◽  
Amey Bailey ◽  
...  
Forests ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1281
Author(s):  
Lenka Sarvašová ◽  
Peter Zach ◽  
Michal Parák ◽  
Miroslav Saniga ◽  
Ján Kulfan

In temperate forests within Europe, early-flushing (EF) deciduous trees are often heavily infested by early spring leaf-eating Lepidoptera, while late-flushing (LF) trees are better protected in a phenological manner against such heavy infestations, as spring moth larvae begin to appear before their bud burst. The associational effects of EF trees on LF ones are only poorly known. We studied whether or not the infestation of LF trees by spring Lepidoptera can be affected by EF ones if they grow in the immediate vicinity. We compared spring assemblages of leaf-eating larvae of Lepidoptera on LF Quercus cerris L. with those on EF Q. pubescens Willd. in several microhabitats in Slovakia, Central Europe. Larvae were collected from mature and young trees. Mature trees sampled were growing: (1) in a closed-canopy forest; (2) in small groups; or (3) as a lone tree. Forest and tree groups are both constituted by oak species. Tree groups and lone trees were 20–50 m distant from forest edges. Young trees were growing (1) under mature Q. pubescens trees in a forest or (2) as a lone tree within forest gaps or near the edges. In the closed-canopy forest where LF trees (Q. cerris) were surrounded by EF ones (Q. pubescens), the caterpillars on mature LF trees were in abundance, almost as on mature EF ones. The species composition of larval assemblages on the two oak species was similar. In contrast, on small groups and on lone trees, the lepidopteran larvae were significantly less abundant on LF trees than EF ones. In the case of young trees, the abundance of larvae and their composition assemblages on both oaks were comparable in the forest. In the open habitat, LF trees were less infested by larvae than EF ones and the assemblages of moth larvae differed between the two. Our results reveal the effect (associational susceptibility) of EF trees on LF ones when growing in a close vicinity. It means that the phenological protection of LF trees may not be sufficient if they grow close to or are surrounded by EF ones.


2013 ◽  
Vol 6 (4) ◽  
pp. 521-535 ◽  
Author(s):  
Windy K. Kelley ◽  
Maria E. Fernandez-Gimenez ◽  
Cynthia S. Brown

AbstractSuccessful management of downy brome (also known as cheatgrass) requires understanding land managers' perceptions and decisions about whether to invest in its control. We investigated ranchers' and natural resource professionals' (NRPs) perceptions and knowledge about downy brome ecology and its impacts, their current downy brome management practices and satisfaction with those practices, and their information and technical needs using focus groups and a mail survey of ranchers and NRPs in Colorado and Wyoming. Both groups thought downy brome was a problem, and perception of the severity of downy brome corresponded to the level of infestation in the respondent's region. NRPs identified downy brome as a bigger problem than did ranchers from the same area in all but one region. Ranchers were most likely to use early spring grazing to control downy brome, and NRPs were most likely to use seeding, imazapic herbicide, or a combination of methods. Both groups reported that the primary constraint to controlling downy brome was that other weeds were a higher priority. Ranchers and NRPs wanted more information about the control methods they were already likely to use as well as other downy brome control methods. Our findings suggest that (1) listing a species as a noxious weed may provide an important incentive to control it, but trade-offs among control efforts for different species must be carefully considered; (2) managers need to know more about low-cost, low-labor strategies for managing downy brome; and (3) some managers need to be informed about how to identify downy brome, its potential negative effects, and how to prevent its spread. Better quantification of the economic and ecological impacts of downy brome in the Central Rocky Mountains, continued development of effective and economically viable management methods, and improvement in the dissemination of that information to land managers are necessary for successful control of downy brome.


2020 ◽  
Vol 33 (21) ◽  
pp. 9261-9269
Author(s):  
Seungmok Paik ◽  
Seung-Ki Min

AbstractThis study conducts a detection and attribution analysis of the observed changes in boreal spring snow-cover extent (SCE) for an extended period of 1925–2019 for early spring (March and April) and 1970–2019 for late spring (May and June) using updated observations and multimodel simulations from phase 6 of the Coupled Model Intercomparison Project (CMIP6). The observed and simulated SCE changes over the Northern Hemisphere (NH), Eurasia, and North America are compared using an optimal fingerprinting technique. Detection results indicate that anthropogenic influences are robustly detected in the observed SCE decrease over NH and the continental regions, in separation from natural forcing influences. In contrast to previous studies, anthropogenic response in the early spring SCE shows a consistent magnitude with observations, due to an extension of the time period to 2019. It is demonstrated for the first time that the greenhouse gas (GHG) influence is robustly detected in separation from anthropogenic aerosol and natural forcing influences, and that most of the observed spring SCE decrease is attributable to GHG influences. The observed SCE decline is also found to be closely associated with the surface warming over the corresponding extratropical lands. Our first quantification of GHG contribution to the observed SCE changes has important implications for reliable future projections of the SCE changes and its hydrological and ecological impacts.


2020 ◽  
Vol 637 ◽  
pp. 195-208 ◽  
Author(s):  
EM DeRoy ◽  
R Scott ◽  
NE Hussey ◽  
HJ MacIsaac

The ecological impacts of invasive species are highly variable and mediated by many factors, including both habitat and population abundance. Lionfish Pterois volitans are an invasive marine species which have high reported detrimental effects on prey populations, but whose effects relative to native predators are currently unknown for the recently colonized eastern Gulf of Mexico. We used functional response (FR) methodology to assess the ecological impact of lionfish relative to 2 functionally similar native species (red grouper Epinephelus morio and graysby grouper Cephalopholis cruentata) foraging in a heterogeneous environment. We then combined the per capita impact of each species with their field abundance to obtain a Relative Impact Potential (RIP). RIP assesses the broader ecological impact of invasive relative to native predators, the magnitude of which predicts community-level negative effects of invasive species. Lionfish FR and overall consumption rate was intermediate to that of red grouper (higher) and graysby grouper (lower). However, lionfish had the highest capture efficiency of all species, which was invariant of habitat. Much higher field abundance of lionfish resulted in high RIPs relative to both grouper species, demonstrating that the ecological impact of lionfish in this region will be driven mainly by high abundance and high predator efficiency rather than per capita effect. Our comparative study is the first empirical assessment of lionfish per capita impact and RIP in this region and is one of few such studies to quantify the FR of a marine predator.


2011 ◽  
Vol 63 (2) ◽  
pp. 153-161 ◽  
Author(s):  
Ondřej Koukol
Keyword(s):  

Author(s):  
W.M. Williams ◽  
L.B. Anderson ◽  
B.M. Cooper

In evaluations of clover performances on summer-dry Himatangi sandy soil, it was found that none could match lucerne over summer. Emphasis was therefore placed on production in autumn-winter- early spring when lucerne growth was slow. Evaluations of some winter annual clover species suggested that Trifolium spumosum, T. pallidum, T. resupinatum, and T. vesiculosum would justify further investigation, along with T. subterraneum which is already used in pastures on this soil type. Among the perennial clover species, Kenya white clover (7'. semipilosum) showed outstanding recovery from drought and was the only species to produce significantly in autumn. However, it failed to grow in winter-early spring. Within red clover, materials of New Zealand x Moroccan origin substantially outproduced the commercial cultivars. Within white clover, material from Israel, Italy and Lebanon, as well as progeny of a selected New Zealand plant, showed more rapid recovery from drought stress and subsequently better winter growth than New Zealand commercial material ('Grasslands Huia'). The wider use of plant material of Mediterranean origin and of plants collected in New Zealand dryland pastures is advocated in development of clover cultivars for New Zealand dryland situations.


Author(s):  
I.N. Voronchikhina ◽  
◽  
A.G. Marenkova ◽  
V. S. Rubets ◽  
V. V. Pylnev

The results of elements development of varietal agrotechnics of a new high-potential line 238h of winter triticale presented. It was identified that under the conditions of 2020 the most cost effective fertilizer system is an early spring application of NPK (S) (15-15-15 (10)) at a dose of 200kg/ha. The profitability level of this fertilizer was 88,9%.


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