Hendrik Coenraad Blöte

The first comprehensive species distribution models for orchid, its fungal symbionts and pollinator are presented. To evaluate impact of global warming on these organisms three different projections and four various climate change scenarios were analysed. The niche modelling was based on presence-only records of Limodorum abortivum , two species of Russula and three insects pollinating orchid ( Anthophora affinis, Bombus terrestris, Rhodanthidium septemdentatum ). Two sets of orchid predictions were examined—the first one included only climatic data and the second one was based on climate data and data on future distribution of orchid fungal symbionts. Overall, a poleward range shift is predicted to occur as a result of climate change and apparently global warming will be favorable for L. abortivum and its potential geographical range will expand. However, due to the negative effect of global warming on fungal symbionts of L. abortivum , the actual extension of the suitable niches of the orchid will be much limited. Considering future possibility of cross-pollination, the availability of A. affinis for L. abortivum will decrease and this bee will be available in the worst case scenarios only for 21% of orchid populations. On the other hand, the overlap of orchid and the buff-tailed bumblebee will increase and as much as 86.5% of plant populations will be located within B. terrestris potential range. Also the availability of R. septemdentatum will be higher than currently observed in almost all analysed climate change projections. This study showed the importance of inclusion of ecological factors in species distribution models as the climate data itself are not enough to estimate the future distribution of plant species. Moreover, the availability of pollen vectors which is crucial for long-term survival of orchid populations should be analysed in context of climate changes.

The Wallacean shortfall refers to the knowledge gap in biodiversity distributions. There is still limited knowledge for freshwater fish species despite the importance of focusing conservation efforts towards this group due to their alarming extinction risk and the increasing human pressure on freshwater ecosystems. Here, we addressed the Wallacean shortfall for freshwater fish faunas across Europe by using the completeness indicator derived from species accumulation curves to quantify the fish sampling efforts. The multiple potential drivers of completeness that were previously related to the sampling efforts for other species (i.e., population density, nature reserves, or distance to cities) were tested using a 10 × 10 km2 grid resolution, as well as environmental (e.g., climatic) factors. Our results suggested that although there was an overall spatial pattern at the European level, the completeness was highly country-dependent. Accessibility parameters explained the sampling efforts, as for other taxa. Likewise, climate factors were related to survey completeness, possibly pointing to the river conditions required for fish sampling. The survey effort map we provide can be used to optimize future sampling, aiming at filling the data gaps in undersampled regions like the eastern European countries, as well as to account for the current bias in any ecological modeling using such data, with important implications for conservation and management.

Xylella fastidiosa is a pathogen that causes fatal plant diseases and damage to horticultural crops. Establishing the basic parameters is necessary to assess the risk of disease outbreaks as there are concerns about the spread of X. fastidiosa. This is done by analyzing the climatic characteristics and distribution patterns of X. fastidiosa and related insect vectors. In this study, we aimed to derive the common climatic characteristics of X. fastidiosa and three major insect vectors by using a statistical density function for four climatic factors. In addition, the distance between the occurrence areas was calculated spatiotemporally and classified into natural and anthropogenic spread. The optimal climatic conditions identified for X. fastidiosa and the insect vectors were similar, suggesting a high potential for X. fastidiosa spread when both occur in a neighborhood area. X. fastidiosa spread mostly depends on anthropogenic pathways, but natural spread by insect vectors could increase. This study provides necessary insights for the risk assessment of X. fastidiosa spread based on climate similarity and spread patterns.

Many benthic invertebrate taxa possess planktonic early life stages which drift with water currents and contribute to dispersal of the species, sometimes reaching areas beyond the current ranges of the adults. Until recently, it had been difficult to identify planktonic larvae to species level due to lack of distinguishing features, preventing detection of expatriate species. Here we used DNA metabarcoding of the COI gene to obtain species-level identification of early life stages of benthic invertebrates in zooplankton samples from the Barents Sea and around Svalbard, where, regionally, large volumes of warm Atlantic Water enter the Arctic from the south. We compared the larval community in the water column to the adult community on the seafloor to identify mismatches. In addition, we implemented particle tracking analysis to identify the possible areas of origin of larvae. Our results show that 30–45% of larval taxa—largely polychaetes and nudibranchs—were not local to the sampling area, though most were found nearby in the Barents Sea. In the particle tracking analysis, some larvae originating along the Norwegian coast were capable of reaching the northwest coast of Svalbard within 3 mo, but larvae found east of Svalbard had a more constrained possible area of origin which did not extend to the Norwegian coast. This study highlights largely regional-scale larval connectivity in the Barents Sea but demonstrates the potential for some long-lived larval taxa to travel to Svalbard and the Barents Sea from further south.

Four anguillid eel species occur in the western Indian Ocean rivers of Africa: Anguilla bengalensis, Anguilla bicolor, Anguilla marmorata and Anguilla mossambica. These catadromous fishes face multiple stressors, including habitat alteration and deterioration, barriers to migration, pollution and the adverse impacts of alien species, but knowledge of eel species occurrence, abundance and ecology in Africa remains poor.This study investigated the present and historical distribution of anguillid eels and the potential associated drivers of declines at the southern extremities of their ranges in South Africa. Data analysed included sampling conducted in KwaZulu–Natal and Eastern Cape between 2015 and 2020, and secondary data extracted from databases, museums and local management agencies.The median extent of inland penetration increased as follows: 22 km for A. bicolor, 29 km for A. marmorata, 94 km for A. bengalensis and 293 km for A. mossambica. The median altitude followed a similar pattern.Extent of occurrence analyses were carried out at the regional level in KwaZulu–Natal. The sampling data on present distribution (2015–2020), compared with historical data, suggests declines in the extents of occurrence of the four eel species in KwaZulu–Natal, ranging between 31 and 48% in the last 30 years and between 35 and 82% since the 1950s.With increasing human threats in the region, especially from watercourse modification and water abstraction, further declines for these species are expected. Conservation measures recommended include the maintenance or restoration of the ecological connectivity of important rivers and the implementation of freshwater protected areas. Although eels are at present not widely exploited in South Africa, there is a need for fisheries regulations to manage sustainable commercial exploitation.

The aim of this study was to evaluate the impact of global warming on suitable niches of montane orchid, Traunsteinera globosa, using ecological niche modelling approach. Additionally, the effect of various climate change scenarios on future changes in the distribution and overlap of the orchid magn…

The Qinghai-Tibetan Plateau (QTP) harbors abundant and diverse plant life owing to its high habitat heterogeneity. However, the distribution pattern of biodiversity hotspots and their conservation status remain unclear. Based on 148,283 high-resolution occurrence coordinates of 13,450 seed plants, w…

Mollusca is the largest marine phylum, comprising about 23% of all named marine organisms, Mollusca systematics are still in flux, and an increase in human activities has affected Molluscan reproduction and development, strongly impacting diversity and classification. Therefore, it is necessary to e…

Amphipod crustaceans are an essential component of tropical marine biodiversity. However, their distribution and biogeography have not been analysed in one of the world’s largest tropical countries nested in the Coral Triangle, Indonesia. We collected and identified amphipod crustaceans from eight s…