scholarly journals Plant diversity changes in a nature reserve: a probabilistic sampling method for quantitative assessments

2019 ◽  
Vol 34 ◽  
pp. 145-161 ◽  
Author(s):  
Stefano Chelli ◽  
Enrico Simonetti ◽  
Giandiego Campetella ◽  
Alessandro Chiarucci ◽  
Marco Cervellini ◽  
...  

Species pool conservation is critical for the stability of ecosystem processes. However, climate and land use changes will likely affect biodiversity, and managers of protected areas are under increasing pressure to monitor native species diversity changes by approaches that are scientifically sound and comparable over time. Here we describe a plant diversity monitoring system in use since 2002 in the “Montagna di Torricchio” Nature Reserve (LTER_EU_IT_033), a Central Apennines representative area of 317 ha, most of which is under strict protection. The aim of this paper was to assess changes in plant species richness over time and to deduce the patterns of species assemblage. The monitoring system was based on a probabilistic sampling design representative of the different physiognomic vegetation types occurring in the Reserve. A total of 34 plots (10×10m) were sampled in 2002, 2003 and 2015, and their species presence/absence and relative coverage were estimated. Repeated measure ANOVA was used to test for plot-level and ecosystem-based changes in species richness along the study period. Temporal nestedness and temporal turnover metrics were used to assess patterns of species’ compositional changes. The results showed significantly different levels of species richness depending on the year, with the lowest value in 2003, probably linked to extreme drought events. Forest systems were comparatively stable, demonstrating the capacity to buffer interannual climate variability. Regarding compositional changes along the entire period (2002–2015), we found random patterns of both temporal nestedness and turnover, indicating stability in species composition. However, we also showed the contemporary occurrence of species loss and species replacement processes, considering the dry year 2003, a finding which should be further explored through fine-scale studies to unravel mechanisms of community assembly under drought. The use of a probabilistic sampling design representative of the different physiognomic vegetation types proved to be advantageous in monitoring the Nature Reserve vegetation and collecting reliable quantitative information. This data, in turn, provides the basis for improvements in management practices and proposed adaptation measures.

2020 ◽  
Vol 13 (5) ◽  
pp. 611-620
Author(s):  
Feng-Wei Xu ◽  
Jian-Jun Li ◽  
Li-Ji Wu ◽  
Xiao-Ming Lu ◽  
Wen Xing ◽  
...  

Abstract Aims Long-term heavy grazing reduces plant diversity and ecosystem function by intensifying nitrogen (N) and water limitation. In contrast, the absence of biomass removal can cause species loss by elevating light competition and weakening community stability, which is exacerbated by N and water enrichment. Hence, how to maintain species diversity and community stability is still a huge challenge for sustainable management of worldwide grasslands. Methods We conducted a 4-year manipulated experiment in six long-term grazing blocks to explore combination of resource additions and biomass removal (increased water, N and light availability) on species richness and community stability in semiarid grasslands of Inner Mongolia, China. Important Findings In all blocks treated with the combination of resource additions and biomass removal, primary productivity increased and species richness and community stability were maintained over 4 years of experiment. At both species and plant functional group (PFG) levels, the aboveground biomass of treated plants remained temporally stable in treatments with the combination of N and/or water addition and biomass removal. The maintenance of species richness was primarily caused by the biomass removal, which could increase the amount of light exposure for grasses under resource enrichment. Both species asynchrony and stability of PFGs contributed to the high temporal stability observed in these communities. Our results indicate that management practices of combined resource enrichment with biomass removal, such as grazing or mowing, could not only enhance primary productivity but also maintain plant species diversity, species asynchrony and community stability. Furthermore, as overgrazing-induced degradation and resource enrichment-induced biodiversity loss continue to be major problems worldwide, our findings have important implications for adaptive management in semiarid grasslands and beyond.


2013 ◽  
Vol 59 (12) ◽  
pp. 803-813 ◽  
Author(s):  
Qi-Sha Liu ◽  
Shu-Zhen Yan ◽  
Jun-Yong Dai ◽  
Shuang-Lin Chen

The species diversity of corticolous myxomycetes on 4 vegetation types in the Tianmu Mountain National Natural Reserve, eastern China, was examined from 2011 to 2012. A total of 1440 moist chamber cultures were prepared with bark samples, which yielded several hundred collections representing 42 species in 20 genera. It was found that 79% of cultures produced some evidence (either plasmodia or fruiting bodies) of myxomycetes. Eight species (Comatricha elegans, Cribraria confusa, Licea pusilla, Cribraria microcarpa, Collaria arcyrionema, Licea biforis, Arcyria cinerea, and Clastoderma debaryanum) were abundant (exceeding 3% of all records), but about a third of all species were classified as rare. Species richness (S = 33) and diversity (exp[H′] = 16.60, S/G = 1.74) of corticolous myxomycetes were the most diverse in the deciduous broadleaf forest. The species recorded from coniferous forest showed the lowest species richness (S = 21) but the highest evenness (J′ = 0.91). The cluster analyses were based on the Bray–Curtis similarity matrix, and the results indicated that corticolous myxomycete assemblages were distributed by a seasonal and annual pattern. Canonical correspondence analysis showed that season and pH were key factors in determining species distribution.


2021 ◽  
Vol 8 ◽  
Author(s):  
Martin A. Mörsdorf ◽  
Virve T. Ravolainen ◽  
Nigel G. Yoccoz ◽  
Thóra Ellen Thórhallsdóttir ◽  
Ingibjörg Svala Jónsdóttir

Tundra plant communities are often shaped by topography. Contrasting wind exposure, slopes of different inclination and landforms of different curvature affect habitat conditions and shape plant diversity patterns. The majority of tundra is also grazed by ungulates, which may alter topographically induced plant diversity patterns, but such effects may depend on the spatial scales of assessments. Here we ask whether topographically induced patterns of within (alpha) and between (beta) plant community diversity are different in contrasting grazing regimes. We studied plant communities within tundra landscapes that were located in the North and Northwest of Iceland. Half of the studied landscapes were grazed by sheep, whereas the other half was currently un-grazed and recovering for several decades (up to 60 years). Alpha and beta diversity were assessed on explicitly defined, nested spatial scales, which were determined by topographical units. Although we contrasted currently grazed vegetation to vegetation that witnessed several decades of grazing recovery, we found no statistically significant differences in plant diversity patterns. We relate these findings to the low resilience of our study system toward grazing disturbances, which has important implications for management practices in the tundra. Effects of topography on species richness were only found for specific spatial scales of analyses. Species rich topographical units were associated with relatively large biomass of plant growth forms that promote nutrient availability and potential plant productivity in the tundra, such as forbs. This suggests that biomass of such plant growth forms within habitats can be a useful proxy of potential plant productivity and may predict spatial patterns of plant species richness in tundra.


2009 ◽  
Vol 31 (2) ◽  
pp. 97 ◽  
Author(s):  
N. L. Bougher ◽  
J. A. Friend

Gilbert’s potoroo (Potorous gilbertii) was previously widespread in south-west Australia but is now restricted to one location – a granitic area of shrubby heath at Two Peoples Bay Nature Reserve on the south coast of Western Australia. To alleviate the threat of extinction a program is under way to establish potoroos in other locations. At Two Peoples Bay Gilbert’s potoroos feed almost exclusively on truffle fungi. However, it was not known whether potoroos translocated to any new areas would be able to rapidly access and consume fungi after translocation, or whether truffles could be a sustainable food supporting breeding populations of potoroos in translocation sites. Furthermore, it was not known whether translocation of potoroos would be successful only in areas with vegetation similar to their refuge at Two Peoples Bay. The current study addressed these questions by analysing the diet of potoroos translocated into two contrasting areas – one on Bald Island with similar topography and vegetation to that of Two Peoples Bay, and the other a 14-ha enclosure on the mainland dominated by Eucalyptus–Allocasuarina woodland. The diet of potoroos was characterised by microscopic examination of scats from individuals trapped after their translocation to these areas. At Bald Island a diverse range of fungi was consumed immediately after translocation. Four potoroos released onto the island only 4–8 days previously consumed 23 species of fungi. Consumption was sustained over time. Three potoroos released onto Bald Island 1–2 years previously and one island-born individual consumed 27 species of fungi during a two-day sampling period. Nine of the 27 fungi species were the same as those that had been consumed by the potoroos within days after their release onto the island. This indicates that production of fungi and their consumption by potoroos on the island was sustained at least 1–2 years after translocation. Potoroos bred on Bald Island during this period. During the same period, two potoroos that were moved from captivity to the mainland site (Ryedene) were consuming six species of truffles within 29 days after release, and 14 species within three months. Such data indicate that a wider selection of vegetation types and areas than just those similar to where potoroos occur at Two Peoples Bay may be able to sustain potoroos and should be investigated for future translocations.


2021 ◽  
Author(s):  
Cecilia Marisol Pech Cutis ◽  
Luis Enrique Castillo Sánchez ◽  
Jorge Rodolfo Canul Solís ◽  
Ermilo López Coba ◽  
Nery Maria Ruz Febles ◽  
...  

The overuse of pesticides, landscape fragmentation and poor environmental management practices have contributed to the drastic decline of Neotropical unique biodiversity. Parasitoid wasps are widely used as biological control agents, however little is known about the effects of land use and degradation on parasitoid species richness and abundance. This work explores how parasitoid species richness is affected by agroecosystems in which plant diversity is limited (crops; crops adjacent to secondary vegetation). It was found that there is no direct effect of plant diversity in the group of parasitoids studied; however, the number of specialist species (koinobionts) was high, which indicates that diversified  agroecosystems probably function as remnants of natural habitat. Future research could help further understand the extent to which landscape fragmentation and plant diversity may alter host-plants interactions and parasitism strategies.


Weed Science ◽  
2020 ◽  
pp. 1-7
Author(s):  
Connor L. Hodgskiss ◽  
Travis R. Legleiter ◽  
Bryan G. Young ◽  
William G. Johnson

Abstract The addition of dicamba as a weed control option in soybean [Glycine max (L.) Merr.] is a valuable tool. However, this technology must be utilized with other herbicide sites of action (SOAs) to reduce selection pressure on weed communities and ensure its prolonged usefulness. A long-term trial was conducted for 7 yr in Indiana to evaluate weed community densities and species richness with four levels of dicamba selection pressure in a corn (Zea mays L.)–soybean rotation. Monocot densities and richness increased over time in the dicamba-reliant treatment. Dicot densities in the dicamba-reliant treatment declined over time, but dicot richness increased. The soil weed seedbank was affected by the varying herbicide strategies. The dicamba-reliant strategy had greater than 43% higher total weed density than all other treatments, primarily due to having a monocot density that was at least 71% higher than the other treatments. The fully diversified strategy with eight SOAs and residual herbicides used every year had the lowest total weed species richness in the soil seedbank, which supported the in-field observations.


2009 ◽  
Vol 57 (2) ◽  
pp. 197-203 ◽  
Author(s):  
T. Sinkovč

The botanical composition of grasslands determines the agronomic and natural values of swards. Good grassland management usually improves herbage value, but on the other hand it frequently decreases the plant diversity and species richness in the swards. In 1999 a field trial in a split-plot design with four replicates was therefore established on the Arrhenatherion type of vegetation in Ljubljana marsh meadows in order to investigate this relationship. Cutting regimes (2 cuts — with normal and delayed first cut, 3 cuts and 4 cuts per year) were allocated to the main plots and fertiliser treatments (zero fertiliser — control, PK and NPK with 2 or 3 N rates) were allocated to the sub-plots. The results at the 1 st cutting in the 5 th trial year were as follows: Fertilising either with PK or NPK had no significant negative effect on plant diversity in any of the cutting regimes. In most treatments the plant number even increased slightly compared to the control. On average, 20 species were listed on both unfertilised and fertilised swards. At this low to moderate level of exploitation intensity, the increased number of cuts had no significant negative effect on plant diversity either (19 species at 2 cuts vs. 20 species at 3 or 4 cuts). PK fertilisation increased the proportion of legumes in the herbage in the case of 2 or 3 cuts. The proportion of grasses in the herbage increased in all the fertilisation treatments with an increased numbers of cuts. Fertiliser treatment considerably reduced the proportion of marsh horsetail ( Equisetum palustre ) in the herbage of the meadows. This effect was even more pronounced at higher cut numbers. The proportion of Equisetum palustre in the herbage was the highest in the unfertilised sward with 2 cuts (26.4 %) and the lowest in the NPK-fertilised sward with 4 cuts (1.4%).


The Condor ◽  
2021 ◽  
Author(s):  
Kyle D Kittelberger ◽  
Montague H C Neate-Clegg ◽  
Evan R Buechley ◽  
Çağan Hakkı Şekercioğlu

Abstract Tropical mountains are global hotspots for birdlife. However, there is a dearth of baseline avifaunal data along elevational gradients, particularly in Africa, limiting our ability to observe and assess changes over time in tropical montane avian communities. In this study, we undertook a multi-year assessment of understory birds along a 1,750 m elevational gradient (1,430–3,186 m) in an Afrotropical moist evergreen montane forest within Ethiopia’s Bale Mountains. Analyzing 6 years of systematic bird-banding data from 5 sites, we describe the patterns of species richness, abundance, community composition, and demographic rates over space and time. We found bimodal patterns in observed and estimated species richness across the elevational gradient (peaking at 1,430 and 2,388 m), although no sites reached asymptotic species richness throughout the study. Species turnover was high across the gradient, though forested sites at mid-elevations resembled each other in species composition. We found significant variation across sites in bird abundance in some of the dietary and habitat guilds. However, we did not find any significant trends in species richness or guild abundances over time. For the majority of analyzed species, capture rates did not change over time and there were no changes in species’ mean elevations. Population growth rates, recruitment rates, and apparent survival rates averaged 1.02, 0.52, and 0.51 respectively, and there were no elevational patterns in demographic rates. This study establishes a multi-year baseline for Afrotropical birds along an elevational gradient in an under-studied international biodiversity hotspot. These data will be critical in assessing the long-term responses of tropical montane birdlife to climate change and habitat degradation.


Author(s):  
Róbert Kun ◽  
Dániel Babai ◽  
András István Csathó ◽  
Csaba Vadász ◽  
Nikoletta Kálmán ◽  
...  

AbstractLocal, adaptive traditional grassland management systems have played a fundamental role in the creation, maintenance and conservation of high nature value (HNV) grasslands. The state of diverse HNV grasslands has deteriorated across Europe in conjunction with changes in various management factors, such as management type and management intensity. To conserve the species-rich vegetation of HNV grasslands and to avoid undesirable shifts in plant functional type dominance, it is important to explore the effects of management factors crucial for nature conservation and to adapt them to local circumstances. In our study, we focus on three of the main factors in the management of valuable meadow steppes in the Great Hungarian Plain region (Central Hungary). We studied management types (mowing, grazing and combined), different levels of herbage removal intensity (low, medium, high) and spatio-temporal complexity (low, medium and high) of grassland management. Altogether 172 plots (1 m × 1 m) were designated in 17 sites. Plant diversity indexes and plant functional types were calculated according to the presence and percentage cover of plant species in the plots. Regarding plant diversity and the dominance of plant functional types, herbage removal intensity and spatio-temporal complexity of management had, for the most part, stronger effects than the type of management. Higher spatio-temporal complexity of management resulted in higher plant diversity, while higher intensity of management led to significantly lower diversity. Proper application of type, intensity and spatio-temporal complexity of management practices (separately and in combination) proved to be determining factors in the long-term maintenance and conservation of diversity and species composition of HNV grasslands.


2011 ◽  
Vol 8 (3) ◽  
pp. 397-400 ◽  
Author(s):  
Jake L. Snaddon ◽  
Edgar C. Turner ◽  
Tom M. Fayle ◽  
Chey V. Khen ◽  
Paul Eggleton ◽  
...  

The exceptionally high species richness of arthropods in tropical rainforests hinges on the complexity of the forest itself: that is, on features such as the high plant diversity, the layered nature of the canopy and the abundance and the diversity of epiphytes and litter. We here report on one important, but almost completely neglected, piece of this complex jigsaw—the intricate network of rhizomorph-forming fungi that ramify through the vegetation of the lower canopy and intercept falling leaf litter. We show that this litter-trapping network is abundant and intercepts substantial amounts of litter (257.3 kg ha −1 ): this exceeds the amount of material recorded in any other rainforest litter-trapping system. Experimental removal of this fungal network resulted in a dramatic reduction in both the abundance (decreased by 70.2 ± 4.1%) and morphospecies richness (decreased by 57.4 ± 5.1%) of arthropods. Since the lower canopy levels can contain the highest densities of arthropods, the proportion of the rainforest fauna dependent on the fungal networks is likely to be substantial. Fungal litter-trapping systems are therefore a crucial component of habitat complexity, providing a vital resource that contributes significantly to rainforest biodiversity.


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