Chinese Forest Research Articles

Identification of benzo[a]pyrene-metabolizing bacteria in forest soils by using DNA-based stable-isotope probing.

DNA-based stable-isotope probing (DNA-SIP) was used in this study to investigate the uncultivated bacteria with benzo[a]pyrene (BaP) metabolism capacities in two Chinese forest soils (Mt. Maoer in Heilongjiang Province and Mt. Baicaowa in Hubei Province). We characterized three different phylotypes with responsibility for BaP degradation, none of which were previously reported as BaP-degrading microorganisms by SIP. In Mt. Maoer soil microcosms, the putative BaP degraders were classified as belonging to the genus Terrimonas (family Chitinophagaceae, order Sphingobacteriales), whereas Burkholderia spp. were the key BaP degraders in Mt. Baicaowa soils. The addition of metabolic salicylate significantly increased BaP degradation efficiency in Mt. Maoer soils, and the BaP-metabolizing bacteria shifted to the microorganisms in the family Oxalobacteraceae (genus unclassified). Meanwhile, salicylate addition did not change either BaP degradation or putative BaP degraders in Mt. Baicaowa. Polycyclic aromatic hydrocarbon ring-hydroxylating dioxygenase (PAH-RHD) genes were amplified, sequenced, and quantified in the DNA-SIP (13)C heavy fraction to further confirm the BaP metabolism. By illuminating the microbial diversity and salicylate additive effects on BaP degradation across different soils, the results increased our understanding of BaP natural attenuation and provided a possible approach to enhance the bioremediation of BaP-contaminated soils.

MODIS Based Estimation of Forest Aboveground Biomass in China.

Accurate estimation of forest biomass C stock is essential to understand carbon cycles. However, current estimates of Chinese forest biomass are mostly based on inventory-based timber volumes and empirical conversion factors at the provincial scale, which could introduce large uncertainties in forest biomass estimation. Here we provide a data-driven estimate of Chinese forest aboveground biomass from 2001 to 2013 at a spatial resolution of 1 km by integrating a recently reviewed plot-level ground-measured forest aboveground biomass database with geospatial information from 1-km Moderate-Resolution Imaging Spectroradiometer (MODIS) dataset in a machine learning algorithm (the model tree ensemble, MTE). We show that Chinese forest aboveground biomass is 8.56 Pg C, which is mainly contributed by evergreen needle-leaf forests and deciduous broadleaf forests. The mean forest aboveground biomass density is 56.1 Mg C ha−1, with high values observed in temperate humid regions. The responses of forest aboveground biomass density to mean annual temperature are closely tied to water conditions; that is, negative responses dominate regions with mean annual precipitation less than 1300 mm y−1 and positive responses prevail in regions with mean annual precipitation higher than 2800 mm y−1. During the 2000s, the forests in China sequestered C by 61.9 Tg C y−1, and this C sink is mainly distributed in north China and may be attributed to warming climate, rising CO2 concentration, N deposition, and growth of young forests.

Intra- and inter-specific differences in crown architecture in Chinese subtropical mixed-species forests

Absorption of photosynthetically active radiation (APAR) is fundamental for tree growth and is strongly influenced by crown architecture. The aim of this study was to quantify the intra- and inter-specific variability in crown architecture in monospecific and mixed-species subtropical Chinese forests. A total of 68 trees, including Castanopsis eyrei, Castanopsis sclerophylla, Cunninghamia lanceolata, Cyclobalanopsis glauca and Liquidambar formosana were destructively sampled and their crown architectures were quantified in terms of the vertical distribution of live branch diameter, individual branch leaf area, leaf area and leaf-area density. The vertical distributions were fitted by a two-parameter right truncated Weibull distribution. Inter-specific variability was assessed using ANCOVA and post hoc Tukey tests and intra-specific variability was assessed by fitting linear and linear mixed effect models. The peak in the vertical distribution of leaf area was highest for the least shade tolerant species, L. formosana (relative depth into the crown of 0.5), intermediate for C. sclerophylla (0.55), C. glauca (0.55) and C. lanceolata (0.6) and lowest for C. eyrei (0.75). For all species, the vertical distribution of leaf area was influenced by tree size except for C. glauca. For L. formosana and C. lanceolata, the distribution of leaf area or branch sizes shifted upwards as tree diameter increased, possibly to overtop neighbouring trees. In contrast, as C. eyrei stem diameter increased, the vertical distribution of mean branch diameter shifted downwards, indicating that larger C. eyrei trees invested a higher proportion of their crown growth into their lower crown when compared to smaller trees. The vertical distribution of leaf-area density varied between species but not within a given species. Crown architectures were not influenced by stand density (basal area) or the species composition of the plot. This intra-specific consistency is useful for modelling light in forests. This study shows that there is a significant inter-specific variability in the crown architectures of the co-occurring species in these subtropical forests. There is also significant intra-specific variability related to tree size and this relationship varies between species. This crown architectural variability and its effect on stand structure are likely to influence the light absorption of these stands.

Growth mechanism for cluster entrepreneurship of peasant households

Purpose – The purposes of this paper are to explore how the cluster entrepreneurship of peasant households in the Chinese forest zone develops, and to analyze how the influence of kinship and geopolitical relations can effectively construct a mechanism for the growth of cluster entrepreneurship. Design/methodology/approach – The case study method was chosen to analyze the growth process of this cluster entrepreneurship (e.g. raising chickens in Zhenghe, planting tea in Anxi and cultivating fruit in Taizhou). Findings – The authors found that the trust, learning and driving mechanisms of cluster entrepreneurship were influenced by kinship and geopolitical relationships, and were included in the building of the growth mechanism of such cluster entrepreneurship, as has emerged. Further, in the building of this evolution mechanism, three paths of growth were found: financial support, the introduction of technology and the introduction of management. Originality/value – This paper enriches the understanding of how cluster entrepreneurship develops in the socioeconomic environment of the Chinese forest zone, with particular reference to kinship and geopolitical relations, and how these contribute to the growth mechanism of cluster entrepreneurship, which is important for the management of entrepreneurial activities in that habitat.

National Forest Aboveground Biomass Mapping from ICESat/GLAS Data and MODIS Imagery in China

Forest aboveground biomass (AGB) was mapped throughout China using large footprint LiDAR waveform data from the Geoscience Laser Altimeter System (GLAS) onboard NASA’s Ice, Cloud, and land Elevation Satellite (ICESat), Moderate Resolution Imaging Spectro-radiometer (MODIS) imagery and forest inventory data. The entire land of China was divided into seven zones according to the geographic characteristics of the forests. The forest AGB prediction models were separately developed for different forest types in each of the seven forest zones at GLAS footprint level from GLAS waveform parameters and biomass derived from height and diameter at breast height (DBH) field observation. Some waveform parameters used in the prediction models were able to reduce the effects of slope on biomass estimation. The models of GLAS-based biomass estimates were developed by using GLAS footprints with slopes less than 20° and slopes ≥ 20°, respectively. Then, all GLAS footprint biomass and MODIS data were used to establish Random Forest regression models for extrapolating footprint AGB to a nationwide scale. The total amount of estimated AGB in Chinese forests around 2006 was about 12,622 Mt vs. 12,617 Mt derived from the seventh national forest resource inventory data. Nearly half of all provinces showed a relative error (%) of less than 20%, and 80% of total provinces had relative errors less than 50%.

Testing predictions of the energetic equivalence rule in forest communities

As growth rate is a reasonable proxy measure of the rate of resource use per plant individual, the ‘energetic equivalence rule’ predicts that net primary productivity (the rate of biomass production per unit area, NPP) will be independent of plant biomass and maximum population density in plant communities. However, only a few studies have tested these relationships in plant communities. In this study, we investigated allometric scaling of net primary productivity (NPP) to tree biomass (M) and density (N) across a range of tree-dominated communities in China. The aim was to test the universality of the ‘energetic equivalence rule’ (i.e. whether the exponents of these relationships take a universal value of 0) in forest communities. We used both ordinary least square (OLS) and standardized major axis (SMA) regression for selected boundary points, and quantile regression (QR) to estimate the slopes of regression lines. QR, OLS and SMA regression all showed that four NPP–M and two NPP–N exponents were different from 0 across the 8 forest types. In addition, when we combined all the data to determine a larger pattern that typifies Chinese forests, five out of the six exponents of NPP–M and NPP–N relationships deviated strongly from 0. Therefore the universality of the ‘energetic equivalence rule’ does not hold for forest communities at both the regional and the national scale of China. However, the “zero” exponent seems to be a central tendency for NPP–M and NPP–N relationships in 7 out of 8 forest types. Deviation from the energetic equivalence possibly reflects multiple, unsound assumptions for “an average idealized forest” by metabolic scaling theory, as well as unaccounted-for variations of site factors (e.g. stand age and stand conditions) within forest communities. In addition, our study suggested that statistical methods should be subject to strict scrutiny in testing the ‘energetic equivalence rule’.

Spatial distribution of old and emerging flame retardants in Chinese forest soils: sources, trends and processes.

The levels and distribution of polybrominated diphenylethers (PBDEs), novel brominated flame retardants (NBFRs) and Dechlorane Plus (DP) in soils and their dependence on environmental and anthropological factors were investigated in 159 soil samples from 30 background forested mountain sites across China. Decabromodiphenylethane (DBDPE) was the most abundant flame retardant (25-18,000 pg g(-1) and 5-13,000 pg g(-1) in O-horizon and A-horizon, respectively), followed by BDE 209 (nd-5900 pg g(-1) and nd-2400 pg g(-1) in O-horizon and A-horizon, respectively). FRs distributions were primarily controlled by source distribution. The distributions of most phasing-out PBDEs, DP isomers and TBPH were in fact correlated to a population density-based index used as proxy of areas with elevated usage and waste of FR containing products. High concentrations of some NBFRs were however observed in industrialized regions and FR manufacturing plants. Strongly positive correlations were observed between PBDEs and their replacement products suggesting similar emission pattern and environmental behavior. Exposure of mineral subsoils depended on precipitations driving leaching of FRs into the soil core. This was especially evident for some emerging BFRs (TBE, TBPH, and TBB etc.) possibly indicating potential for diffuse groundwater contamination.

A latitudinal gradient in tree community assembly processes evidenced in Chinese forests

AbstractAimMost studies on latitudinal gradients of biodiversity have focused on gradients of species richness. Here we aim to test whether, on top of these strong diversity gradients, processes of community assembly vary along a latitudinal gradient of more than 33°.LocationChina, latitude 18.67–51.86° N.MethodsWe used species abundance distribution (SAD) data collected in 32 forest tree plots, and fitted a non‐neutral model of community assembly to these SADs. We then calculated the fitted deviation from neutrality, δ, and looked for correlations between δ and geographical and environmental data.ResultsThe fitted parameter δ was positive in most plots, and was furthermore positively correlated with latitude and negatively with temperature, indicating a less even abundance distribution and a likely increase in the strength of environmental filtering in regions further from the tropics and with decreasing temperatures. These results imply that on top of reducing the species richness, cold temperature may impact community assembly processes by strengthening local environmental filtering.Main conclusionsOur results suggest a latitudinal gradient in tree community assembly process in Chinese forests, in which deviations from neutrality increase with latitude, probably because of an increase in environmental harshness.

Control of Microcystis aeruginosa with Galla chinensis

Galla chinensis (nutgall), used in traditional Chinese medicine, is a product extracted from nutgall trees in Chinese forests. In this study, Microcystis aeruginosa, a cyanobacterium, was exposed to different concentrations of nutgall extract obtained from Galla chinensis. With increased exposure concentration, and time, the cell density of M. aeruginosa was significantly reduced. After 72 h of exposure, the chlorophyll a content of M. aeruginosa significantly decreased; superoxide dismutase (SOD) activity increased at a low nutgall concentration but decreased at higher concentrations. Cellular ultrastructure was observed by electron microscopy. With increased nutgall concentrations, M. aeruginosa cell walls became wrinkled, collapsed, and ruptured. The photosynthetic thylakoid lamellae were fractured and dispersed, fewer phycobilisomes attached to the photosynthetic thylakoid membrane and were dispersed into the cytoplasm, and the number of lipid particles and cyanophycin granules increased. A large void appeared in the nuclear area and most of the algal cells died. In conclusion, these observations indicate that Galla chinensis has a significant allelopathic effect, and can effectively inhibit the growth of M. aeruginosa

Carbon carry capacity and carbon sequestration potential in China based on an integrated analysis of mature forest biomass.

Forests play an important role in acting as a carbon sink of terrestrial ecosystem. Although global forests have huge carbon carrying capacity (CCC) and carbon sequestration potential (CSP), there were few quantification reports on Chinese forests. We collected and compiled a forest biomass dataset of China, a total of 5841 sites, based on forest inventory and literature search results. From the dataset we extracted 338 sites with forests aged over 80 years, a threshold for defining mature forest, to establish the mature forest biomass dataset. After analyzing the spatial pattern of the carbon density of Chinese mature forests and its controlling factors, we used carbon density of mature forests as the reference level, and conservatively estimated the CCC of the forests in China by interpolation methods of Regression Kriging, Inverse Distance Weighted and Partial Thin Plate Smoothing Spline. Combining with the sixth National Forest Resources Inventory, we also estimated the forest CSP. The results revealed positive relationships between carbon density of mature forests and temperature, precipitation and stand age, and the horizontal and elevational patterns of carbon density of mature forests can be well predicted by temperature and precipitation. The total CCC and CSP of the existing forests are 19.87 and 13.86 Pg C, respectively. Subtropical forests would have more CCC and CSP than other biomes. Consequently, relying on forests to uptake carbon by decreasing disturbance on forests would be an alternative approach for mitigating greenhouse gas concentration effects besides afforestation and reforestation.

Dirty Laundry: Are Chinese Legal Ivory Factories Using Poached Ivory as an Input?

It has been alleged or suspected that the legal ivory factories in China launder poached ivory to make carvings. In this research the throughput of tusks across all 37 factories is analysed. The period covers the first allocation of tusks by the Chinese State Forest Administration in July 2009 up to January 2014. The number of factories is fixed, the number of carvers is stable and ivory carving is time-intensive. Diversion of carver-effort to use illegal ivory must come at the expense of legal output. If laundering is occurring it should have an appreciable effect on the rate at which legal tusks are consumed as carvings. The throughput of 1293 tusks is analysed with two modelling approaches. These were a Vector Error Correction Model (VECM) and a Seemingly Unrelated Regression (SUR) approach. Tusk throughput is affected by the size of the tusk and the experience of the carver. Factories also report tusks used up in production in batches. The models show that this reporting effect is partly explained by the Chinese retail spending cycle. No significant deviation in tusk throughput is detected. This implies that the legal factory system is largely clean of illegal ivory. The results also provide indirect evidence that the illegal ivory entering China is destined largely for a speculative market in raw ivory or for an autonomous illegal factory network.

Prospects for the use of biological control agents against Anoplophora in Europe.

This review summarises the literature on the biological control of Anoplophora spp. (Coleoptera: Cerambycidae) and discusses its potential for use in Europe. Entomopathogenic fungi: Beauveria brongniartii Petch (Hypocreales: Cordycipitaceae) has already been developed into a commercial product in Japan, and fungal infection results in high mortality rates. Parasitic nematodes: Steinernema feltiae Filipjev (Rhabditida: Steinernematidae) and Steinernema carpocapsae Weiser have potential for use as biopesticides as an alternative to chemical treatments. Parasitoids: a parasitoid of Anoplophora chinensis Forster, Aprostocetus anoplophorae Delvare (Hymenoptera: Eulophidae), was discovered in Italy in 2002 and has been shown to be capable of parasitising up to 72% of A. chinensis eggs; some native European parasitoid species (e.g. Spathius erythrocephalus) also have potential to be used as biological control agents. Predators: two woodpecker (Piciformis: Picidae) species that are native to Europe, Dendrocopos major Beicki and Picus canus Gmelin, have been shown to be effective at controlling Anoplophora glabripennis Motschulsky in Chinese forests. The removal and destruction of infested and potentially infested trees is the main eradication strategy for Anoplophora spp. in Europe, but biological control agents could be used in the future to complement other management strategies, especially in locations where eradication is no longer possible.

The forest resources input–output model: An application in China

Understanding the state of forest resource utilization in China and correctly evaluating the role and function of forest resources in national economic development are essential for realizing balanced development of forests, the environment, and the economy. This is especially true given the present situation of increasingly scarce forest resources. Using data from Chinese forest industry statistical yearbooks, forestry development reports, and other documents, this paper examines the current state of forest resource utilization in China from the angle of combining quantities and values based on input–output tables. We show that demand for and input use of forest resources varies greatly across industrial sectors; the paper products and furniture manufacturing industries have the greatest direct consumption coefficient for timber use. When considering direct and indirect demand, it is clear that forest resources restrict different industrial sectors in diverse ways. These results provide an important set of reference values regarding the utilization of forest resources and coordinated industrial development in China.

Investigation and Analysis of the Lending Needs of Forestry Households in China: Based on Data from Zhejiang, Fujian, Guangxi, and Jiangxi Provinces

As the collective forestry property system in China has developed in recent years, the difficulty faced by forestry households (the main managers of Chinese forests) in securing loans has received extensive attention. To address this problem, we should follow the bottom-up principle and undertake effective measures based on a clear understanding of forestry financing. Based on the results of a questionnaire, this article investigates and analyzes the credit demand in forestry households, lending channels, scaling, time limits, loan usage, and cost structures. Studies have shown that funding deficits contribute to the intense demand for loans. The salient characteristics of foresters’ credit demand indicate that such demand is typically large-scale and of long duration—particularly when compared with the credit demand of common farmers. Loans to foresters are used for production purposes and mainly come from formal financing. The structural dislocation of current forestry loan products has resulted in a demand for forestry farming credit that is difficult to satisfy. Therefore, improving the quality of credit services and optimizing loan product structures would help foresters and the Chinese forestry industry.

Game analysis of Chinese stakeholders in collective forest rights system reform

In the current stage of Chinese forest ownership reform, the central and local governments as well as the forest farmers play different roles with variations in their expected returns. Managing these respective relationships between the forestry stakeholders to maximize their benefits while actively engaging each stakeholder in the collective forest ownership reform process has become an important issue. This study uses the game theory methodology to analyze the relationship between the different reform stakeholders and then builds on the forest farmers’ participation in the reform model process at the reform movement micro-level. This model calculates the forest products equilibrium marketing sales and the government subsidies provided to the forest farmers, when the forest farmers willingly participate in the reform process. It will provide a reliable basis for formulation of government policies which positively impacts Chinese forestry reform.

Estimating Forest Aboveground Biomass by Combining ALOS PALSAR and WorldView-2 Data: A Case Study at Purple Mountain National Park, Nanjing, China

Enhanced methods are required for mapping the forest aboveground biomass (AGB) over a large area in Chinese forests. This study attempted to develop an improved approach to retrieving biomass by combining PALSAR (Phased Array type L-band Synthetic Aperture Radar) and WorldView-2 data. A total of 33 variables with potential correlations with forest biomass were extracted from the above data. However, these parameters had poor fits to the observed biomass. Accordingly, the synergies of several variables were explored to identify improved relationships with the AGB. Using principal component analysis and multivariate linear regression (MLR), the accuracies of the biomass estimates obtained using PALSAR and WorldView-2 data were improved to approximately 65% to 71%. In addition, using the additional dataset developed from the fusion of FBD (fine beam dual-polarization) and WorldView-2 data improved the performance to 79% with an RMSE (root mean square error) of 35.13 Mg/ha when using the MLR method. Moreover, a further improvement (R2 = 0.89, relative RMSE = 17.08%) was obtained by combining all the variables mentioned above. For the purpose of comparison with MLR, a neural network approach was also used to estimate the biomass. However, this approach did not produce significant improvements in the AGB estimates. Consequently, the final MLR model was recommended to map the AGB of the study area. Finally, analyses of estimated error in distinguishing forest types and vertical structures suggested that the RMSE decreases gradually from broad-leaved to coniferous to mixed forest. In terms of different vertical structures (VS), VS3 has a high error because the forest lacks undergrowth trees, while VS4 forest, which has approximately the same amounts of stems in each of the three DBH (diameter at breast height) classes (DBH > 20, 10 ≤ DBH ≤ 20, and DBH < 10 cm), has the lowest RMSE. This study demonstrates that the combination of PALSAR and WorldView-2 data is a promising approach to improve biomass estimation.

Biomass and its allocation of Chinese forest ecosystems

Forest biomass and its allocation have long been considered important in forest ecosystem structure and function. However, discrete forest biomass data and its allocation to various forest components must be standardized to explore many ecological questions, e.g., plant allometric scaling laws, biomass allocation theory, and terrestrial carbon cycling. Currently, available data sets focus either on regions other than China, or studies in China are spatially and/or temporally limited, e.g., specific habitats and/or time periods. Therefore, the applicability of conclusions to world or China forests might be problematic. Consequently, in the present study, published studies (during the 1978–2008 period) on biomass and its allocations in China's forests (excluding Hong Kong, Macao, and Taiwan) were collected and critically reviewed, and a comprehensive forest biomass data set of China was developed. The data set included the following biomass data: tree overstory components (stems, branches, leaves, and roots, among all other plant material), the understory vegetation (saplings, shrubs, herbs, and mosses), woody liana vegetation, and the necromass components of dead organic matter (litterfall, suspended branches, and dead trees). Moreover, associated information was also included, i.e., geographical location, climate, soil fertility, stand description, sampling regime (the dimension and sample size of plots), and biomass measurement methods. The data set included 1607 entries for 348 study sites, which exhibited a broad spatial distribution, and covered broad climatic gradients (−5.1°C to 23.8°C in mean annual temperature and 223–2515 mm in mean annual precipitation). Our data set can be used to verify the accuracy of models used to budget China's forest carbon dynamics, and also provides an opportunity to further elucidate and confirm general principles and patterns in ecology. Finally, the data set is freely available for noncommercial scientific applications.

Tree species traits but not diversity mitigate stem breakage in a subtropical forest following a rare and extreme ice storm.

Future climates are likely to include extreme events, which in turn have great impacts on ecological systems. In this study, we investigated possible effects that could mitigate stem breakage caused by a rare and extreme ice storm in a Chinese subtropical forest across a gradient of forest diversity. We used Bayesian modeling to correct stem breakage for tree size and variance components analysis to quantify the influence of taxon, leaf and wood functional traits, and stand level properties on the probability of stem breakage. We show that the taxon explained four times more variance in individual stem breakage than did stand level properties; trees with higher specific leaf area (SLA) were less susceptible to breakage. However, a large part of the variation at the taxon scale remained unexplained, implying that unmeasured or undefined traits could be used to predict damage caused by ice storms. When aggregated at the plot level, functional diversity and wood density increased after the ice storm. We suggest that for the adaption of forest management to climate change, much can still be learned from looking at functional traits at the taxon level.

Scaling relationships between leaf mass and total plant mass across Chinese forests.

Biomass partitioning is important for illustrating terrestrial ecosystem carbon flux. West, Brown and Enquist (WBE) model predicts that an optimal 3/4 allometric scaling of leaf mass and total biomass of individual plants will be applied in diverse communities. However, amount of scientific evidence suggests an involvement of some biological and environmental factors in interpreting the variation of scaling exponent observed in empirical studies. In this paper, biomass information of 1175 forested communities in China was collected and categorized into groups in terms of leaf form and function, as well as their locations to test whether the allocation pattern was conserved or variable with internal and/or environmental variations. Model Type II regression protocol was adopted to perform all the regressions. The results empirically showed that the slopes varied significantly across diverse forested biomes, between conifer and broadleaved forests, and between evergreen and deciduous forests. Based on the results, leaf form and function and their relations to environments play a significant role in the modification of the WBE model to explore more accurate laws in nature.

Relative roles of local disturbance, current climate and paleoclimate in determining phylogenetic and functional diversity in Chinese forests

Abstract. The main processes underlying the generation and maintenance of biodiversity include both local factors such as competition and abiotic filtering and regional forces such as paleoclimate, speciation and dispersal. While the effects of regional and local drivers on species diversity are increasingly studied, their relative importance for other aspects of diversity, notably phylogenetic and functional diversity is so far little studied. Here, we link data from large Chinese forest plots to data on current and Last Glacial Maximum (LGM) climate as well as local disturbance regimes to study their relative roles in determining woody plant phylogenetic and functional diversity in this important hotspot for woody plant diversity. Local disturbance was the best predictor of functional diversity as represented by maximum canopy height (Hmax), probably reflecting the dominant role of competition for light in determining the forest Hmax structure. In contrast, the LGM–present anomaly in temperature was the factor with the strongest explanatory power for phylogenetic diversity, with modern climate also important. Hence, local contemporary and regional historical factors have highly contrasting importance for the geographic patterns of the functional (as represented by variation in maximum canopy height) and phylogenetic aspects of Chinese forest's woody plant diversity. Importantly, contemporary factors are of overriding importance for functional diversity, while paleoclimate has left a strong signature in the phylogenetic diversity patterns.