Effects of fire disturbance on ant abundance and diversity: a global meta-analysis

2016 ◽  
Vol 26 (1) ◽  
pp. 177-188 ◽  
Author(s):  
Heraldo L. Vasconcelos ◽  
Jonas B. Maravalhas ◽  
Tatiana Cornelissen
2020 ◽  
Author(s):  
Pavel Saska ◽  
David Makowski ◽  
David Bohan ◽  
Wopke van der Werf

AbstractCarabid beetles (Coleoptera: Carabidae) provide important ecological services and are frequently used as a bio-indicator in monitoring environmental quality. The abundance and diversity of carabids is usually determined using pitfall trapping, but trap catches are difficult to compare between studies due to variation in trapping effort. The standardization of the catch for trapping effort has not been previously addressed in a global analysis of studies in the literature.The aims of this study are (i) to define a method for estimating the effect of trapping effort on the size of the pitfall catch, and (ii) to explore factors related to study designs, sampling method, study origin, and level of data aggregation to determine how these factors affect the catch per unit effort in pitfall trapping.We conducted a meta-analysis on the activity-density and diversity of carabids across studies, based on published data from Europe and North-America to analyse whether standardization of catch measurements might be possible. Data were extracted from 104 publications, spanning a period of 42 years.The total catch was proportional to the number of trap days, and ranged from 0.19-9.53 beetles/(trap day) across studies (95% range), with a mean of 1.33 beetles/(trap day). The number of species was allometrically related to the trapping effort defined as the product of the number of traps, their perimeter and the time of exposure in the field, and characterized by a power exponent of 0.25. Species richness ranged across studies from 2.30-13.18 species/(m day)0.25 (95% range) with a mean of 7.15 species/(m day)0.25. The size of the catch and the number of species were higher in crops with narrow as compared to wide rows. There was no significant change in abundance or diversity of carabids in arable land over the 42 years covered. We also found that increasing trapping effort may not yield more accurate results.The results show that it is possible to standardize activity-density-based catches and species diversity for trapping effort across studies using a power transformation, allowing meta-analysis of such data, e.g. to elucidate factors affecting abundance and diversity of the focal taxa.


Geoderma ◽  
2022 ◽  
Vol 411 ◽  
pp. 115694
Author(s):  
Yakun Zhang ◽  
Sai Peng ◽  
Xinli Chen ◽  
Han Y.H. Chen

Oceans ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 162-178
Author(s):  
Richard K. F. Unsworth ◽  
Alex Higgs ◽  
Bettina Walter ◽  
Leanne C. Cullen-Unsworth ◽  
Isabella Inman ◽  
...  

A growing body of research is documenting the accumulation of microplastics within marine sediments around the world. The hydrodynamic influences of seagrasses in coastal environments are shown to increase sedimentation of finer particles and as a result there has been speculation that this attribute will lead to seagrass meadows acting as a site of elevated microplastic contamination. To date a range of localised studies have provided conflicting answers to this hypothesis. Seagrass meadows provide multiple ecosystem services including vital support roles for a range of fisheries; therefore, there are considerable human health implications for understanding their role as sinks of microplastics. This research investigated the abundance and diversity of microplastics present in temperate North Atlantic seagrass meadow sediments relative to unvegetated sediments and examined how they correlate with the meadow structure and the sediment type. We also placed this data in the context of the current knowledge of microplastics in seagrass sediments through a global meta-analysis of published data. Eight seagrass meadows and adjacent unvegetated sites around the UK were sampled to test for the abundance of microplastic particles in the sediment. Microplastics were found in 98% of the samples, with fibres making up 91.8% of all microplastics identified. Abundance was recorded to overall be 215 ± 163 microplastic particles (MP) kg−1 Dry Weight (DW) of sediment in seagrass and 221 ± 236 MP kg−1 DW of sediment in unvegetated habitats. There were no significant differences found between the number of MP with respect to vegetation. We report evidence of the almost ubiquitous contamination of seagrass sediments with microplastics both in the UK and globally but find that the contamination reflects a general build-up of microplastics in the wider environment rather than becoming concentrated within seagrass as an enhanced sink. Microplastic build up in sediments is hypothesised to be the result of local hydrodynamics and plastic sources rather than the result of elevated habitat level concentration. Although not of a higher abundance in seagrass, such contamination in seagrass is of cause for concern given the high dependency of many species of fish on these habitat types and the potential for plastics to move up the food chain.


2021 ◽  
Author(s):  
Alex Stemmelen ◽  
Hervé Jactel ◽  
Eckehard Brockerhoff ◽  
Bastien Castagneyrol

The natural enemies hypothesis predicts that the abundance and diversity of antagonists such as predators and parasitoids of herbivores increases with the diversity of plants, which can lead to more effective top-down control of insect herbivores. However, although the hypothesis has received large support in agricultural systems, fewer studies have been conducted in forest ecosystems and a comprehensive synthesis of previous research is still lacking. We conducted a meta-analysis of 65 publications comparing the diversity, abundance or activity of various groups of natural enemies (including birds, bats, spiders and insect parasitoids) in pure vs. mixed forest stands. We tested the effects of forest biome, natural enemy taxon and type of study (managed vs experimental forest). We found a significant positive effect of forest tree diversity on natural enemy abundance and diversity but not on their activity. The effect of tree diversity on natural enemies was stronger towards lower latitudes but was not contingent on the natural enemy taxon. Overall, our study contributes substantially toward a better understanding of the natural enemies hypothesis in forest systems and provides new insights about the mechanisms involved. Furthermore, we outline potential avenues for strengthening forest resistance to the growing threat of herbivorous insects.


2021 ◽  
Vol 25 (7) ◽  
pp. 191-193
Author(s):  
Mayank Tripathi

Utility of some modern methods (Growth Response Coefficient and Pathway Analysis) in analysing RGR and its components (NAR, SLA, LMF) has been depicted in the present study. Studies related to RGR are complex. Moreover, it is impractical for a researcher to study the entire spectrum of plant functional groups due to abundance and diversity of species in nature. RGR often varies between functional groups and in different environmental conditions as well. It is desirable to observe and identify characteristic patterns in plant growth models for better management practices. To achieve this goal, a more holistic approach is adopted which scrutinizes experimental data from number of independent studies in order to establish overall trends in RGR. The method is called meta-analysis. The, above mentioned statistical methods can further assist evolutionary biologists in tracing the evolutionary and phylogenetic characteristics of plants, the knowledge of which can be applied for modelling RGRs in future.


2018 ◽  
Author(s):  
Luke Barrett ◽  
Stephen E Swearer ◽  
Tim Dempster

The global expansion of aquaculture has raised concerns about its environmental impacts, including effects on wildlife. Aquaculture farms are thought to repel some species and function as either attractive population sinks (‘ecological traps’) or population sources for others. We conducted a systematic review and meta‐analysis of empirical studies documenting interactions between aquaculture operations and vertebrate wildlife. Farms were associated with elevated local abundance and diversity of wildlife, although this overall effect was strongly driven by aggregations of wild fish at sea cages and shellfish farms (abundance: 72×; species richness: 2.0×). Birds were also more diverse at farms (1.1×), but other taxa showed variable and comparatively small effects. Larger effects were reported when researchers selected featureless or unstructured habitats as reference sites. Evidence for aggregation ‘hotspots’ is clear in some systems, but we cannot determine whether farms act as ecological traps for most taxa, as few studies assess either habitat preference or fitness in wildlife. Fish collected near farms were larger and heavier with no change in body condition, but also faced higher risk of disease and parasitism. Birds and mammals were frequently reported preying on stock, but little data exist on the outcomes of such interactions for birds and mammals – farms are likely to function as ecological traps for many species. We recommend researchers measure survival and reproduction in farm‐associated wildlife to make direct, causal links between aquaculture and its effects on wildlife populations.


2019 ◽  
Vol 2 ◽  
Author(s):  
Pavel Saska ◽  
Britta Frei ◽  
David Makowski ◽  
Wopke van der Werf

Recent studies have shown dramatic decline in the abundance and diversity of insects over the last decades, including pollinators, lepidopterans, flying insects, parasitoids or epigeal predators, such as carabid and staphylinid beetles. Many of these studies are based on regional data, therefore it is hard to draw a conclusion about the generality of the reported effects across multiple groups and regions. In this paper we focus on testing the hypothesis of insect decline in annual arable crops over a wide geographical range, using meta-analysis of data on carabid beetles as a model group. We extracted pitfall trap catches and observed species richness from 105 independent publications originating from Europe and North America. Data were from a variety of arable annual crops in 22 countries, and spanned a period of 42 years. As sampling effort varied notably across studies, we standardized catches by trapping effort, and explored different options for calculating trapping effort from data. The data over time did not show any evidence of a decline in carabid numbers nor species caught over the 42 years covered by the dataset. A possible explanation for this finding is that carabid beetles living in these habitats are adapted to periodical disturbance by either withstanding these disturbances on site or by periodically re-colonizing fields from adjacent habitats. Although local decreases in carabid populations are documented in the literature as a result of agricultural intensification or landscape simplification, at the broader geographical scale, such a decline is not supported by the data.


2021 ◽  
Author(s):  
Andreas Y Troumbis

Abstract The generalization that specific seed traits such as dormancy, longevity, or heat-triggered germination of plant species expanding in pyrogenic environments where stochastically but recurrently fire disturbance occurs is a fitness increasing adaptation of obligate seeders dates from the early 20th century. During the last few decades, this hypothesis, qualified as a pyrophytic strategy, is re-evaluated under the lenses of conservation biology and climate change research. The validity of pyrophytism as an equilibrium response to fire vs. the interpretation that the obligate seeding strategy is instead an opportunistic or generalist response to the multitude of abiotic and biotic factors determining the variability and heterogeneity of fire-prone environments such as the Mediterranean Type Ecosystems is indirectly examined and narratively promoted in the renewed fire ecology literature. In this paper, I suggest a need for a typified meta-analysis of the abundant but disparate wealth of research protocols and data to achieve a quantitatively strict understanding of the limits of the contrasting hypotheses. I develop a meta-analytic classifier and test its feasibility and applicability across taxonomic, biologic, and ecological levels of organization, i.e., from the intra-population or inter-individual local level progressively to inter-genus and intra-family levels, across the Mediterranean Basin. Cistaceae species, emblems of the Mediterranean shrublands, are the model for this research. The results of this exercise support the feasibility and flexibility of the Lehmann-type classifier developed. Although Cistus species do respond positively to heat-shocks at the local level, significant variability is uncovered among higher taxa levels and furthermost as the environmental variability increases. The germination variability complicates generalizations when climatic variability and change come into play, questioning long-standing ‘certitudes’ and Mediterranean forest managers and conservation planners' practices.


2021 ◽  
Author(s):  
Yali Wei ◽  
Yan Meng ◽  
Na Li ◽  
Qian Wang ◽  
Liyong Chen

The purpose of the systematic review and meta-analysis was to determine if low-ratio n-6/n-3 long-chain polyunsaturated fatty acid (PUFA) supplementation affects serum inflammation markers based on current studies.


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