Forest management intensity affects aquatic communities in artificial tree holes

Forest management could potentially affect organisms in all forest habitats. However, aquatic communities in water-filled tree-holes may be especially sensitive because of small population sizes, the risk of drought and potential dispersal limitation. We set up artificial tree holes in forest stands subject to different management intensities in two regions in Germany and assessed the influence of local environmental properties (tree-hole opening type, tree diameter, water volume and water temperature) as well as regional drivers (forest management intensity, tree-hole density) on tree-hole insect communities (not considering other organisms such as nematodes or rotifers), detritus content, oxygen and nutrient concentrations. In addition, we compared data from artificial tree holes with data from natural tree holes in the same area to evaluate the methodological approach of using tree-hole analogues. We found that forest management had strong effects on communities in artificial tree holes in both regions and across the season. Abundance and species richness declined, community composition shifted and detritus content declined with increasing forest management intensity. Environmental variables, such as tree-hole density and tree diameter partly explained these changes. However, dispersal limitation, indicated by effects of tree-hole density, generally showed rather weak impacts on communities. Artificial tree holes had higher water temperatures (on average 2° C higher) and oxygen concentrations (on average 25% higher) than natural tree holes. The abundance of organisms was higher but species richness was lower in artificial tree holes. Community composition differed between artificial and natural tree holes. Negative management effects were detectable in both tree-hole systems, despite their abiotic and biotic differences. Our results indicate that forest management has substantial and pervasive effects on tree-hole communities and may alter their structure and functioning. We furthermore conclude that artificial tree-hole analogues represent a useful experimental alternative to test effects of changes in forest management on natural communities.Fil: Petermann, Jana S.. University of Salzburg; Austria. Berlin-Brandenburg Institute of Advanced Biodiversity Research; AlemaniaFil: Rohland, Anja. Friedrich Schiller University; AlemaniaFil: Sichardt, Nora. Friedrich Schiller University; AlemaniaFil: Lade, Peggy. Friedrich Schiller University; AlemaniaFil: Guidetti, Brenda Yamile. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Friedrich Schiller University; AlemaniaFil: Weisser, Wolfgang W.. Friedrich Schiller University; Alemania. Technische Universität München; AlemaniaFil: Gossner, Martin M.. Friedrich Schiller University; Alemania. Technische Universität München; Alemani

Characterization of genetic diversity of Trachemys dorbigni and Phrynops hilarii

The utilization of RAPD and ISSR molecular markers is proposed to initiate studies of genetic variability in Phrynops hilarii and Trachemys dorbigni, two species of fresh water turtles distributed in South America. Three primers of RAPD and four of ISSR were selected and the amplified products of these markers were evaluated by electrophoretic runs in agarose and polyacrylamide gels. The levels of heterozygosity, Shannon index and different allele numbers were slightly higher in P. hilarii for both types of markers. Levels of polymorphism were also higher in P. hilarii than T. dorbigni and both were elevated compared to those recorded for other species. The fact that similar results were obtained with both types of markers for all estimates of diversity highlights the usefulness and validity of the RAPD technique. The molecular markers used were found potentially useful for analysing future temporal and spatial distribution of genetic diversity in both species, expanding scales work.Fil: Guidetti, Brenda Yamile. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias. Departamento de Ciencias Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Siroski, Pablo Ariel. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias. Departamento de Cs.naturales. Laboratorio de Zoología Aplicada: Anexo Vertebrados (fhuc-unl/maspyma); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Amavet, Patricia Susana. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias. Departamento de Ciencias Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentin

Artificial perches promote vegetation restoration

Native ecosystems are continuously being transformed mostly into agricultural lands. Simultaneously, a large proportion of fields are abandoned after some years of use. Without any intervention, altered landscapes usually show a slow reversion to native ecosystems, or to novel ecosystems. One of the main barriers to vegetation regeneration is poor propagule supply. Many restoration programs have already implemented the use of artificial perches in order to increase seed availability in open areas where bird dispersal is limited by the lack of trees. To evaluate the effectiveness of this practice, we performed a series of meta-analyses comparing the use of artificial perches versus control sites without perches. We found that setting-up artificial perches increases the abundance and richness of seeds that arrive in altered areas surrounding native ecosystems. Moreover, density of seedlings is also higher in open areas with artificial perches than in control sites without perches. Taken together, our results support the use of artificial perches to overcome the problem of poor seed availability in degraded fields, promoting and/or accelerating the restoration of vegetation in concordance with the surrounding landscape.EEA ParanáFil: Guidetti, Brenda Yamile. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Paraná; ParanáFil: Amico, Guillermo Cesar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; ArgentinaFil: Dardanelli, Sebastian. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Paraná; ArgentinaFil: Rodriguez Cabal, Mariano Alberto. University of British Columbia; Canadá. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentin

Artificial perches for birds in deforested areas favour a seed rain similar to woodland remnants

The lack of seeds represents one of the highest difficulties to overcome for the ecological restoration of areas that have been deforested. This study evaluates the effectiveness of artificial perches in increasing the abundance and species richness of bird-dispersed seeds and the similarity of seed rain composition of deforested areas with and without artificial perches in relation to woodland remnants that serve as seeds source. We also tested for differences in seed abundance and species richness with different origins (native or non-native) as well as different type of habits (woody and non-woody). The experiment took place in two sites of the Espinal ecoregion, Argentina. We found that in deforested areas, perches increased seed abundance and species richness in the seed rain in comparison with deforested areas without artificial perches. The species composition under artificial perches was similar to the seed rain dispersed in the woodland. However, there was a decrease in the abundance and richness of native species under artificial perches, probably due to behavioral differences between opportunistic and obligate frugivorous. Seed of trees and shrubs species that can act as natural perches and nurses were well represented in the seed rain under artificial perches. We recommend using artificial perches in deforested areas with potential for recovery because it is an efficient technique to promote the entry of birds and increase seed rain, preserving features of the original environment. In places where native and non-native species show different fructification peaks, artificial perches could be used in certain periods of the year.EEA ParanáFil: Guidetti, Brenda Yamile. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; ArgentinaFil: Guidetti, Brenda Yamile. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Dardanelli, Sebastian. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Paraná; ArgentinaFil: Dardanelli, Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; ArgentinaFil: Miño, Fátima María Lucrecia. Universidad Autónoma de Entre Ríos. Facultad de Ciencia y Tecnología; ArgentinaFil: Amico, Guillermo Cesar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; Argentin

Petermann16_artificial tree holes

Petermann16_artificial tree hole

Experimental design.

<p>In the two regions (Alb and Hainich), we set up six artificial tree holes in each of 29 and 24 plots, respectively. In the Alb, three of the holes in each plot had openings at the side, three at the top. In the Hainich, all tree holes had top openings. Tree holes were installed in April. In the Alb, all tree holes were collected in June, in the Hainich, three were harvested in June, three remained until September. Tree holes in the Alb had a maximum volume of 10l, in the Hainich a substantially lower maximum volume of 600ml. For further information on tree-hole characteristics and measurements in the two regions, see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0155549#pone.0155549.s007" target="_blank">S1 Table</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0155549#pone.0155549.s002" target="_blank">S2 Fig</a>. Table numbers in the figure refer to tables with the respective statistical analyses for the data sets: <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0155549#pone.0155549.t001" target="_blank">Table 1A and 1B</a> for data sets involving June data in the Alb and June and September data in the Hainich, respectively, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0155549#pone.0155549.s008" target="_blank">S2 Table</a> for June data (and additional environmental variables) in the Hainich. Grey areas depict forests, white areas non-forest habitats. Maps reprinted with permission from Landesamt für Geoinformation und Landentwicklung Baden-Württemberg (17.03.2016, Az.: 2851.2-D/7537 <a href="http://www.lgl-bw.de" target="_blank">www.lgl-bw.de</a>) for the Alb and from GeoBasisDE / TLVermGeo (2016) for the Hainich.</p

Mixed model results for abundance and richness.

<p>Mixed model results for abundance and richness.</p

Comparison of macroinvertebrate communities of artificial and natural tree holes in the two regions in June.

<p>A) abundance (square-root transformed), B) species richness and C), D) composition. Artificial holes are depicted by black bars and symbols, natural holes by grey bars and symbols. Average water volume differed between artificial and natural tree holes (artificial tree holes had larger average volume). However, the differences in abundance and richness between artificial and natural tree holes were still significant after fitting water volume as a covariate (for results of statistical analyses see text). Raw abundance and species richness (i.e. not adjusted for differences in volume) are shown here. The low overlap between artificial and natural communities in the composition plots (C, D) shows that community composition differed between artificial and natural tree holes in both regions. Only taxa with more than five occurrences per region across both tree-hole types were used for the nonmetric multidimensional scaling (NMDS) plots in C and D. Stress = 0.17, n = 214 for Alb, stress = 0.21, n = 124, for Hainich. Please note that experimental set-up and the volume of artificial tree holes also varied between the two regions, so they cannot be compared directly.</p

Insect community composition.

<p>Nonmetric multidimensional scaling (NMDS) plot showing the composition of insect communities in artificial tree holes in the two regions in June: A) Alb, B) Hainich. Red symbols in A represent artificial holes with a side opening, symbols in black are artificial tree holes with a top opening. The size of the symbols represents the density of natural tree holes in the respective plots. Forest management intensity affected community composition in the Alb and in the Hainich as shown by the arrow drawn by fitting forest management intensity <i>post hoc</i> and indicating tree holes in plots with high and low forest management. Opening type and tree-hole density had an effect on community composition in the Alb only (shown by the clustering of similar symbols). For results of statistical analyses, see text. Only taxa with more than five occurrences per region across both tree-hole types were used for the plots. Stress = 0.16, n = 137 for Alb, stress = 0.19, n = 134, for Hainich.</p

Effect of forest management intensity on difference in detritus volume.

<p>Difference in volume of detritus in the artificial tree holes was calculated between the start of the experiment and harvesting time (June or September). Values above zero represent a net gain, below zero a net loss of detritus from the tree hole. Data are from the Hainich region (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0155549#pone.0155549.s010" target="_blank">S4 Table</a>) from June (closed symbols and solid lines) or from September (open symbols and dashed line). Symbols represent means per plot, error bars show ±SE. Forest management intensity was calculated according to Kahl and Bauhus [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0155549#pone.0155549.ref030" target="_blank">30</a>]. For results of statistical analyses see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0155549#pone.0155549.s010" target="_blank">S4 Table</a>.</p