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Featured researches published by Konrad Martin.


Biodiversity and Conservation | 2006

Vascular Plant Species Inventory of a Philippine Lowland Rain Forest and its Conservation Value

Gerhard Langenberger; Konrad Martin; Joachim Sauerborn

The Philippines are one of the most important biodiveristy hotspots on earth. Due to the extraordinary rate of environmental destruction, leaving only 3% of the land with primary forest, this biodiversity is at high risk. Despite that situation information on Philippine forest vegetation is fragmentary and focused on trees. This study aimed at analysing forest remnants in the Leyte Cordillera on the Island of Leyte, and at evaluating their role as refuge to the largely destroyed lowland forest vegetation. A total of 49 plots (100 m2 each) between 55 and 520 m a.s.l. were studied. All vascular plant species except epiphytes were included. Records include 685 taxa from 289 genera and 111 families, representing nearly 8% of the known Philippine vascular plant species. More than half (52%) of the species are Philippine endemics. A number of 41 tree species, or 6% of all taxa recorded, are included in the IUCN red list, either as vulnerable, endangered, or critically endangered. Life form composition was dominated by phanerophytes (65.3%), followed by lianas and chamaephytes (17.1 and 16.9%, respectively). The most common families were the Rubiaceae with 35 and the Euphorbiaceae with 32 species. All five Philippine dipterocarp forest types as well as the molave forest type were represented by typical tree species. The area provides an important gene bank of the highly threatened Philippine lowland forest vegetation and is of high value for biodiversity conservation. Additionally, it can play an important role as seed source of valuable tree species for the increasing initiatives to rehabilitate and reforest degraded land with native species.


Agroforestry Systems | 2009

Ethnobotanical knowledge of Philippine lowland farmers and its application in agroforestry

Gerhard Langenberger; Vanessa Prigge; Konrad Martin; Beatriz Belonias; Joachim Sauerborn

Complex agroforestry systems that mimic local forest structure, so-called ‘analogs’, are assumed to be of specific value to rural people as well as the environment. The objective of this study was to document and evaluate the utilization of plant resources by Philippine lowland farmers to identify native species suitable for integration in such a system. The interviewed farmers maintain a comprehensive ethnobotanical knowledge. They reported using 122 plant species for 77 purposes. Eighty species have medicinal value, 35 provide food, and 32 serve other uses. About 64% of the identified species are Philippine natives. The life form composition of these species is dominated by trees but also includes herbs, lianas, and graminoids, thus providing the structural elements required in analog systems. Nevertheless, only a few of the species seem to be promising for cultivation. Many of them are ubiquitous in the vicinity of villages. Some species are also not much appreciated but act as staple food only during food shortage. Even though several of the species have proven market value, such as rattan (e.g. Calamusmerrillii), or are reputed medicines, such as ‘Philippine ginseng’ (Sarcandra glabra), no cultivation could be observed. This shows that usefulness in itself cannot be the only criterion to promote species but that it requires a careful analysis of the marketability of the respective species. In this context we suggest the following three species that are of proven medicinal value for in-depth study: the liana Tinospora crispa (Menispermaceae), the tree Picrasma javanica (Simaroubaceae), and the herb Sarcandra glabra (Chloranthaceae). They represent three different life form strategies and would thus fit well in vertically structured agroforestry systems.


Integrative Zoology | 2012

Spatial and temporal effects on seed dispersal and seed predation of Musa acuminata in southern Yunnan, China.

Ling-Zeng Meng; Xiuxia Gao; Jin Chen; Konrad Martin

Wild bananas are abundant in tropical areas and many ecologists have observed that the succession process is quicker following increased disturbance. This study was conducted to analyze animal-seed interactions and their effects on the seed fate of a wild banana species (Musa acuminata) in tropical southern Yunnan (China) through experiments considering spatial (site and habitat) and temporal (seasons) variation. The largest proportion of fruits (81%) was removed by frugivorous seed dispersers, especially by bats at nighttime. Only 13% of the fruits were removed by climbing seed predators (different species of rats). In the exclosure treatment, rodents accounted for a significantly higher total artificially exposed seed removal number than ants, but with spatial and temporal differences. The highest seed predation rate by rodents (70%) was found in forest with wild banana stands, corresponding with the highest rodent diversity (species numbers and abundance) among the habitat types. In contrast, the seed removal number by ants (57%) was highest in the open land habitats, but there was no close correlation with ant diversity. Seed removal numbers by ants were significantly higher in the dry compared to the rainy season, but rodent activity showed no differences between seasons. The overall results suggest that the largest proportion of seeds produced by wild banana are primarily dispersed by bats. Primary seed dispersal by bats at nighttime is essential for wild banana seeds to escape seed predation.


Agroforestry Systems | 2017

Rubber intercropping: a viable concept for the 21st century?

Gerhard Langenberger; Georg Cadisch; Konrad Martin; Shi Min; Hermann Waibel

The last decades brought along a tremendous expansion of rubber plantations as well as respective socio-economic transformations. This paper reviews the historical development of rubber cultivation with special reference to intercropping and illustrates the major development steps. The agronomic challenges of intercropping are analyzed and a management classification scheme is suggested. Though the topic of labor always accompanied rubber management, it is nowadays of even higher relevance due to alternative income options, be it due to competing crops such as oil palm, or be it off-farm income opportunities. This development challenges labor intensive permanent intercropping systems. It can thus be concluded that the permanent integration of additional plants needs either to be highly profitable or at least be labor extensive to be adopted on a considerable scale. Given the large area of rubber plantations the latter seems to be more realistic. In this context timber trees might offer promising options if tree selection is properly adapted to site and plantation conditions. Nevertheless, without external interventions, such as land-use planning and implementation, or incentives, the development will be difficult to control.


Insect Science | 2012

Contrasting responses of hoverflies and wild bees to habitat structure and land use change in a tropical landscape (southern Yunnan, SW China)

Ling-Zeng Meng; Konrad Martin; Jing-Xin Liu; Frank Burger; Jin Chen

Abstract  The response of insects to monoculture plantations has mainly proceeded at the expense of natural forest areas, and is an outstanding and important issue in ecology and conservation biology, with pollination services declined around the world. In this study, species richness and distribution of hoverfly and wild bee communities were investigated in a changing tropical landscape in southern Yunnan, south‐west China by Malaise traps periodically from 2008 to 2009. Species were recorded from the traditional land use types (natural forest, grassland, shrubland and rice field fallows), and from recently established rubber plantations of different ages. Hoverflies (total 53 species) were most common in young successional stages of vegetation, including rice field fallow and shrubland. Species richness was highest in rice field fallows and lowest in forests and showed a highly significant relationship with the number of forb species and ground vegetation cover. In contrast, the highest richness of wild bees (total 44 species) was recorded from the natural forest sites, which showed a discrete bee community composition compared to the remaining habitat types. There was no significant relationship between the bee species richness and the environmental variables, including the numbers of different plant life forms, coverage of canopy and ground vegetation, successional age of vegetation and land use type. At the landscape scale, open land use systems, including young rubber plantations, are assumed to increase the species richness of hoverflies; however, this might decrease wild bee diversity. The present land use change by rubber cultivation can be expected to have negative impacts on the native wild bee communities.


Pest Management Science | 2009

Entomopathogens (Beauveria bassiana and Steinernema carpocapsae) for biological control of bark-feeding moth Indarbela dea on field-infested litchi trees

Marie Joy Schulte; Konrad Martin; Andreas Büchse; Joachim Sauerborn

BACKGROUND The bark-feeding moth Indarbela dea (Swinhoe) is one of the major pests of litchi (Litchi chinensis Sonn.) in Asia. Effects on larval mortality and web production were tested by repeated, single and combined tree trunk applications of the entomopathogenic fungus Beauveria bassiana (Bals.) Vuill. and the entomopathogenic nematode Steinernema carpocapsae (Weiser). Two separate application trials were conducted in different seasons on young and older larvae respectively. RESULTS In both trials, complete or nearly complete mortality (100% and 95%) of the larvae was achieved 3 weeks after application of S. carpocapsae alone and 2 weeks after the combined application of B. bassiana and S. carpocapsae (100% in both trials). However, in the combined application, all larvae were killed by one treatment, while the application of S. carpocapsae alone needed to be repeated to reach the same result. The effectiveness of the combined entomopathogen application and of the application of S. carpocapsae alone was not influenced by the age of the larvae. However, the single applications of B. bassiana were only effective on young larvae. In both trials, web production of surviving larvae was very significantly reduced by the application of S. carpocapsae in single and combined treatments. CONCLUSIONS As the results show, only one application is necessary in the combined application of the two entomopathogens to control I. dea, which implies that such treatment is probably the economically most relevant solution.


Insect Science | 2007

Biology and control of the fruit borer, Conopomorpha sinensis Bradley on litchi (Litchi chinensis Sonn.) in northern Thailand

Marie Joy Schulte; Konrad Martin; Joachim Sauerborn

Fruit and leaf shoot of litchi (Litchi chinensis) infestation by naturally occurring populations of the fruit borer, Conopomorpha sinensis larvae and C. sinensis parasitization rates were determined in litchi orchards in northern Thailand at high (ca. 1 400 m ASL) and low (ca. 800 m ASL) elevations with different, non‐over‐lapping fruiting seasons. In addition, spray applications of Bacillus thuringiensis var. aizawai, the natural compound spinosad and the chemical pesticide imidacloprid were conducted in the field to test the effects of these agents on C. sinensis fruit infestation rate. Fruit infestation rate and fruit growth, studied in a low elevation orchard, were sigmoidal and showed a highly significant positive correlation (P· 0.01). Leaf shoot infestation rate in the low elevation orchard decreased in the course of the fruiting season (March until May), but increased in the high elevation orchard, where no fruits were present within the same period of time. Together, these results indicate that females of C. sinensis clearly prefer fruits over shoots for oviposition. If no fruits are available, which was the case in the high elevation orchard during that time, they are constrained to lay their eggs on shoots. The parasitization rate of C. sinensis larvae in untreated fruits was 54.3%. The parasitoid species were Chelonus chailini (90.8%) and Phanerotoma sp. (9.2%). In the leaf shoots, C. sinensis was found to be parasitized by Phanerotoma sp. and Apanteles briareus. The applications of the different active agents had no significant effect on C. sinensis fruit infestation compared to the untreated control. Besides the cryptic life of the larvae, this is most probably explained by the fact that C. sinensis has several generations during the fruiting season. Because of the high parasitization rates recorded, an alternative and more effective control measure than the application of pesticides might be the augmentative release of parasitoids.


Journal of Insect Conservation | 2016

Movement patterns of selected insect groups between natural forest, open land and rubber plantation in a tropical landscape (southern Yunnan, SW China)

Ling-Zeng Meng; Xiaodong Yang; Konrad Martin; Jianmin Gan; Yan-Hong Liu; Wei-Chang Gong

Abstract In many regions of tropical Asia, the expansion of rubber monoculture plantations is conducted by replacement of natural forest areas and strongly affects biodiversity and movement patterns of wild species, including insects. Against this background, we conducted a study on selected insect groups (longhorn beetles, bark beetles, wild bees and hoverflies) along transects between rainforest patches, open uncultivated land and rubber plantation habitats in a region of Xishuangbanna (southern Yunnan, China), with the objectives to identify (a) movement directions and patterns of selected insect groups based on their abundances in modified Malaise traps in the different habitats, and (b) the role of remaining natural rainforest patches and rubber plantations, respectively, for insect diversity maintenance and conservation. The highest total numbers of species and individuals of bark beetles, longhorn beetles and wild bees were recorded from the natural forest edge compared to open land and rubber plantation edge. This result clearly indicates that the natural forest plays an important role in maintenance of these three insect groups. However, the highest number of hoverfly species and individuals was recorded from the open land sites, indicating the most relevant habitat type for this group of species. Overall, the lowest species and individual numbers were recorded from the rubber plantation edge, indicating the unsuitability of this habitat type for all insect groups considered. The distribution of species and individuals in the opposite trap sides along the transect indicates that longhorn beetles, bark beetles and wild bees show not only movements from the forest to the surrounding habitats, but also return back after encountering the unsuitable rubber plantation habitat. Bark beetle composition showed the relatively highest similarity between all trap sites and opposite trap sides among the insect groups considered, indicating a higher movement activity than the other groups. The four insect groups considered in this study show different movement modes between the forest, open land and rubber plantation, which are not the same for all taxa. Except for hoverflies, the natural forest was found to be the most important habitat for the maintenance of species diversity in the different land use types of the study area.


Journal of Plant Diseases and Protection | 2007

Efficacy of spiromesifen on Aceria litchii (Keifer) in relation to Cephaleuros virescens Kunze colonization on leaves of litchi (Litchi chinensis Sonn.)

Marie Joy Schulte; Konrad Martin; Joachim Sauerborn

The phytophagous mite, Aceria litchii (Keifer), is one of the major pests of litchi (Litchi chinensis Sonn.) in Asia and Australia. By sucking on the cells of young leaves, the mites cause punctiform lesions. These are used by the parasitic alga Cephaleuros virescens Kunze to penetrate the leaf epidermis by forming a felt-like erineum. In the present study, significant positive relationships between mite density on algal infested leaves on the one hand and algal density and degree of erineum leaf cover on the other were found. In relation to these factors, the efficacy of different concentrations (0.036 g a.i. l−1, 0.072 g a.i. l−1 and 0.144 g a.i. l−1) and application frequencies (single and double) of spiromesifen, a lipid biosynthesis inhibiting agent, on the numbers of A. Litchii on litchi leaves was tested. Single spiromesifen applications significantly reduced numbers of mites per leaf by 34% at medium and by 77% at the highest concentration within 7 days after application. With double applications, numbers of mites were reduced by more than 80% at all concentrations 7 days after the second treatment. A complete elimination of A. Litchii was reached 18 days after the second application of the highest spiromesifen concentration. The degree of erineum cover and algal density did not significantly affect the efficacy of the double spiromesifen treatments, indicating that spiromesifen acts in a dose-dependent manner on A. Litchii.ZusammenfassungEiner der Hauptschädlinge von Litchi (Litchi chinensis Sonn.) in Asien und Australien ist die phytophage Milbe Aceria litchii (Keifer), die durch das Saugen an den Zellen junger Blätter punktförmige Läsionen auf der Blattoberfläche verursacht. Diese werden von der parasitischen Alge Cephaleuros virescens Kunze als Eintrittspforten zur Penetration der Blattepidermis genutzt, wodurch ein fellartiges Erineum entsteht. In der vorliegenden Untersuchung wurden signifikant positive Beziehungen zwischen der Milbendichte auf algeninfizierten Blättern einerseits und der Algendichte sowie dem Blattbedeckungsgrad des Erineums andererseits gefunden. Im Zusammenhang mit diesen Faktoren wurde die Wirksamkeit von Spiromesifen, einem Lipidbiosynthese hemmenden Wirkstoff, in verschiedenen Konzentrationen (0.036 g a.i. l−1, 0.072 g a.i. l−1 und 0.144 g a.i. l−1) und Applikationshäufigkeiten (ein-und zweifach) auf die Milbendichte auf Litchiblättern getestet. Innerhalb von 7 Tagen nach der einfachen Applikation wurde eine signifikante Reduktion in der Zahl der Milben pro Blatt von 34% bei der mittleren und 77% bei der höchsten Konzentration gefunden. Eine zweite Applikation reduzierte die Milbendichte bei allen Konzentrationen nach 7 Tagen um mehr als 80%. Eine vollständige Eliminierung von iA. Litchii wurde 18 Tage nach der zweiten Applikation bei der höchsten Spiromesifenkonzentration erreicht. Der Blattbedeckungsgrad des Erineums und die Algendichte hatten keinen signifikanten Einfluß auf die Wirksamkeit von wiederholten Spiromesifenapplikationen, was auf eine dosisabhängige Wirkungsweise hindeutet.


Archive | 2013

Origin and Development of Agriculture

Konrad Martin; Joachim Sauerborn

The savannas of Africa are believed to be the cradle of mankind. All members of Homo sapiens sapiens living today descended from populations that lived there approximately 150,000–200,000 years ago. Just as two earlier representatives of the genus Homo (H. erectus and the ancestors of the H. neanderthalensis) had done before, groups of modern humans left their homeland to colonize other continents. This occurred between 50,000 and 70,000 years ago. The reasons for this migration, which only began 100,000 years after the emergence of H. sapiens, are subject to speculation. It is possible that the first migrations coincided with changes in climate that also affected resource availability and the living conditions of humans. However, little is known about the diet of early H. sapiens in Africa. He was already a hunter of wild animals, which placed him in competition with large cats and other predators. Humans not only had to defend their prey against these predators, but also to protect themselves. The hunt for large animals for example gazelles, buffalo, or even elephants was of little importance for early humans partially because of their still primitive weapons. Presumably, they used a broad range of food sources including plant products (roots, seeds, and fruit), small animals (e.g. small mammals, reptiles, insects), wild honey, and eggs from birds and reptiles. They probably also ate the remains of large animals, for example bone marrow, which was accessed with the help of stone tools (Fig. 2.1). With the help of fire, it was possible to roast meat and to cook many plant species that were otherwise inedible or even poisonous.

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Dirk Euler

University of Hohenheim

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Jing-Xin Liu

University of Hohenheim

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Jin Chen

Xishuangbanna Tropical Botanical Garden

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Marc Cotter

University of Hohenheim

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