@article{ChaianunpornHovestadt2022, author = {Chaianunporn, Thotsapol and Hovestadt, Thomas}, title = {Emergence of spatially structured populations by area-concentrated search}, series = {Ecology and Evolution}, volume = {12}, journal = {Ecology and Evolution}, number = {12}, doi = {10.1002/ece3.9528}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-311939}, year = {2022}, abstract = {The idea that populations are spatially structured has become a very powerful concept in ecology, raising interest in many research areas. However, despite dispersal being a core component of the concept, it typically does not consider the movement behavior underlying any dispersal. Using individual-based simulations in continuous space, we explored the emergence of a spatially structured population in landscapes with spatially heterogeneous resource distribution and with organisms following simple area-concentrated search (ACS); individuals do not, however, perceive or respond to any habitat attributes per se but only to their foraging success. We investigated the effects of different resource clustering pattern in landscapes (single large cluster vs. many small clusters) and different resource density on the spatial structure of populations and movement between resource clusters of individuals. As results, we found that foraging success increased with increasing resource density and decreasing number of resource clusters. In a wide parameter space, the system exhibited attributes of a spatially structured populations with individuals concentrated in areas of high resource density, searching within areas of resources, and "dispersing" in straight line between resource patches. "Emigration" was more likely from patches that were small or of low quality (low resource density), but we observed an interaction effect between these two parameters. With the ACS implemented, individuals tended to move deeper into a resource cluster in scenarios with moderate resource density than in scenarios with high resource density. "Looping" from patches was more likely if patches were large and of high quality. Our simulations demonstrate that spatial structure in populations may emerge if critical resources are heterogeneously distributed and if individuals follow simple movement rules (such as ACS). Neither the perception of habitat nor an explicit decision to emigrate from a patch on the side of acting individuals is necessary for the emergence of such spatial structure.}, language = {en} } @phdthesis{Lakovic2020, author = {Lakovic, Milica}, title = {Evolution of animal dispersal: Putting timing in perspective}, doi = {10.25972/OPUS-15452}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-154522}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2020}, abstract = {Dispersal is a life-history trait affecting dynamics and persistence of populations; it evolves under various known selective pressures. Theoretical studies on dispersal typically assume 'natal dispersal', where individuals emigrate right after birth. But emigration may also occur during a later moment within a reproductive season ('breeding dispersal'). For example, some female butterflies first deposit eggs in their natal patch before migrating to other site(s) to continue egg-laying there. How breeding compared to natal dispersal influences the evolution of dispersal has not been explored. To close this gap we used an individual-based simulation approach to analyze (i) the evolution of timing of breeding dispersal in annual organisms, (ii) its influence on dispersal (compared to natal dispersal). Furthermore, we tested (iii) its performance in direct evolutionary contest with individuals following a natal dispersal strategy. Our results show that evolution should typically result in lower dispersal under breeding dispersal, especially when costs of dispersal are low and population size is small. By distributing offspring evenly across two patches, breeding dispersal allows reducing direct sibling competition in the next generation whereas natal dispersal can only reduce trans-generational kin competition by producing highly dispersive offspring in each generation. The added benefit of breeding dispersal is most prominent in patches with small population sizes. Finally, the evolutionary contests show that a breeding dispersal strategy would universally out-compete natal dispersal.}, language = {en} } @article{OervoessyKoroesiBataryetal.2014, author = {Oervoessy, Noemi and Koroesi, Adam and Batary, Peter and Vozar, Agnes and Peregovits, Laszlo}, title = {Habitat Requirements of the Protected Southern Festoon (Zerynthia Polysena); Adult, Egg and Larval Distribution in a Highly Degraded Habitat Complex}, series = {Acta Zoologica Academiae Scientiarum Hungaricae}, volume = {60}, journal = {Acta Zoologica Academiae Scientiarum Hungaricae}, number = {4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-117810}, pages = {371-387}, year = {2014}, abstract = {Habitat quality affects the presence and size of butterfly populations. Resources for all life stages must be found in a given or few habitat patches. Southern festoon (Zerynthia polyxena) is a vulnerable, but locally abundant species in Hungary. The larva requires birthwort (Aristolochia clematitis) as food plant. We examined the small scale habitat use of adults and distribution of eggs and larvae among different vegetation types to reveal the requirements of the species in all life stages. Transect counts were conducted in a tree plantation complex comprising four types of vegetation. Number (+/- SE) of adults, eggs and larvae were lowest in poplar plantation (adult 0.3 +/- 0.2, egg 1.1 +/- 1.1, larva 0.6 +/- 0.3). Medium amount of butterflies were observed in open (adult 8.3 +/- 2.9, egg 3.1 +/- 2.6, larva 3.1 +/- 1.9) and black-locust (adult 9.4 +/- 4.2, egg 12.7 +/- 4.9, larva 4.1 +/- 1.1) habitat. Number of butterflies was highest in hummocks (adult 13.5 +/- 1.5, egg 12.9 +/- 5.7, larva 8.4 +/- 2.1). Adults avoided bare ground. We encountered most eggs in dense food plant patches with high plants. Food plant height also positively influenced the occurrence of the larvae. Although distribution of adults and juvenile forms showed quite similar patterns, we could also reveal some differences that caused by different environmental conditions in distinct vegetation types. Our study stresses the importance of habitat quality, which affects population size of butterflies even in a highly degraded habitat complex.}, language = {en} } @article{PoethkeHovestadt2002, author = {Poethke, Hans J. and Hovestadt, Thomas}, title = {Evolution of density-and patch-size-dependent dispersal rates}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-49659}, year = {2002}, abstract = {Based on a marginal value approach, we derive a nonlinear expression for evolutionarily stable (ES) dispersal rates in a metapopulation with global dispersal. For the general case of density-dependent population growth, our analysis shows that individual dispersal rates should decrease with patch capacity and-beyond a certain threshold-increase with population density. We performed a number of spatially explicit, individual-based simulation experiments to test these predictions and to explore further the relevance of variation in the rate of population increase, density dependence, environmental fluctuations and dispersal mortality on the evolution of dispersal rates. They confirm the predictions of our analytical approach. In addition, they show that dispersal rates in metapopulations mostly depend on dispersal mortality and inter-patch variation in population density. The latter is dominantly driven by environmental fluctuations and the rate of population increase. These conclusions are not altered by the introduction of neighbourhood dispersal. With patch capacities in the order of 100 individuals, kin competition seems to be of negligible importance for ES dispersal rates except when overall dispersal rates are low.}, subject = {Metapopulation}, language = {en} } @article{GrosPoethkeHovestadt2009, author = {Gros, Andreas and Poethke, Hans Joachim and Hovestadt, Thomas}, title = {Sex-specific spatio-temporal variability in reproductive success promotes the evolution of sex-biased dispersal}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-48711}, year = {2009}, abstract = {Abstract: Inbreeding depression, asymmetries in costs or benefits of dispersal, and the mating system have been identified as potential factors underlying the evolution of sex-biased dispersal. We use individual-based simulations to explore how the mating system and demographic stochasticity influence the evolution of sex-specific dispersal in a metapopulation with females competing over breeding sites, and males over mating opportunities. Comparison of simulation results for random mating with those for a harem system (locally, a single male sires all offspring) reveal that even extreme variance in local male reproductive success (extreme male competition) does not induce male-biased dispersal. The latter evolves if the between-parch variance in reproductive success is larger for males than females. This can emerge due to demographic stochasticity if the habitat patches are small. More generally, members of a group of individuals experiencing higher spatio-temporal variance in fitness expectations may evolve to disperse with greater probability than others.}, language = {en} } @article{HeisswolfReichmannPoethkeetal.2009, author = {Heisswolf, Annette and Reichmann, Stefanie and Poethke, Hans-Joachim and Schr{\"o}der, Boris and Obermaier, Elisabeth}, title = {Habitat quality matters for the distribution of an endangered leaf beetle and its egg parasitoid in a fragmented landscape}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-47740}, year = {2009}, abstract = {Fragmentation, deterioration, and loss of habitat patches threaten the survival of many insect species. Depending on their trophic level, species may be differently affected by these factors. However, studies investigating more than one trophic level on a landscape scale are still rare. In the present study we analyzed the effects of habitat size, isolation, and quality for the occurrence and population density of the endangered leaf beetle Cassida canaliculata Laich. (Coleoptera: Chrysomelidae) and its egg parasitoid, the hymenopteran wasp Foersterella reptans Nees (Hymenoptera: Tetracampidae). C. canaliculata is strictly monophagous on meadow sage (Salvia pratensis), while F. reptans can also parasitize other hosts. Both size and isolation of habitat patches strongly determined the occurrence of the beetle. However, population density increased to a much greater extent with increasing host plant density ( = habitat quality) than with habitat size. The occurrence probability of the egg parasitoid increased with increasing population density of C. canaliculata. In conclusion, although maintaining large, well-connected patches with high host plant density is surely the major conservation goal for the specialized herbivore C. canaliculata, also small patches with high host plant densities can support viable populations and should thus be conserved. The less specialized parasitoid F. reptans is more likely to be found on patches with high beetle density, while patch size and isolation seem to be less important.}, subject = {Fragmentierung}, language = {en} } @article{PoethkeHovestadtMitesser2003, author = {Poethke, Hans-Joachim and Hovestadt, Thomas and Mitesser, Oliver}, title = {Local extinction and the evolution of dispersal rates: Causes and correlations}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-47718}, year = {2003}, abstract = {We present the results of individual-based simulation experiments on the evolution of dispersal rates of organisms living in metapopulations. We find conflicting results regarding the relationship between local extinction rate and evolutionarily stable (ES) dispersal rate depending on which principal mechanism causes extinction: if extinction is caused by environmental catastrophes eradicating local populations, we observe a positive correlation between extinction and ES dispersal rate; if extinction is a consequence of stochastic local dynamics and environmental fluctuations, the correlation becomes ambiguous; and in cases where extinction is caused by dispersal mortality, a negative correlation between local extinction rate and ES dispersal rate emerges. We conclude that extinction rate, which both affects and is affected by dispersal rates, is not an ideal predictor for optimal dispersal rates.}, subject = {Ausbreitung}, language = {en} } @phdthesis{Hein2004, author = {Hein, Silke}, title = {The survival of grasshoppers and bush crickets in habitats variable in space and time}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-9140}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2004}, abstract = {Die zunehmende Nutzung von Landschaften f{\"u}hrt zu einer steigenden Fragmentierung sch{\"u}tzenswerter Fl{\"a}chen. Damit verbunden ist eine Zerschneidung von großen Populationen in Metapopulationen. In solchen F{\"a}llen bestimmt das Gleichgewicht zwischen Aussterben und Besiedlung von Habitaten die regionale {\"U}berlebenswahrscheinlichkeit von Arten. Um diese bestimmen, braucht man ein gutes Verst{\"a}ndnis der Habitatanspr{\"u}che der Arten, sowie Informationen {\"u}ber ihr Ausbreitungsverhalten. Ziel dieser Arbeit war es, geeignete Fl{\"a}chen f{\"u}r Heuschrecken in einer Landschaft identifizieren zu k{\"o}nnen, sowie einen Beitrag zur Quantifizierung der Erreichbarkeit einzelner Fl{\"a}chen durch Individuen zu leisten. Der erste Teil dieser Arbeit besch{\"a}ftigt sich mit der Quantifizierung der Habitateignung von Fl{\"a}chen f{\"u}r Heuschrecken. Dazu habe ich statistische Habitateignungsmodelle mittels logistischer Regression erstellt, evaluiert und validiert. Es zeigte sich, dass die Habitatwahl der Heuschrecken auf einer mittleren r{\"a}umlichen Skalenebene erfolgt. Dies steht mit der beobachteten Ausbreitungsdistanz der Tiere im Einklang. Neben dem nur grob klassifizierten Landschaftsfaktor „Biotoptyp" korrelieren vor allem strukturelle Faktoren sowie abiotische Faktoren mit dem Vorkommen der Heuschreckenarten. Bei der Bestimmung eines gemeinsamen Models f{\"u}r alle drei Heuschreckenarten erwies sich das Model der Art S. lineatus mit den Parametern Biotoptyp und Vegetationsh{\"o}he als am besten geeignet zur Vorhersage der Vorkommen der anderen Heuschreckenarten. Um zu testen, ob auch die Vorkommen von Arten unterschiedlicher Tiergruppen mittels eines gemeinsamen Modells vorhergesagt werden k{\"o}nnen, habe ich sowohl die Heuschreckenmodelle zur Prognose von Faltervorkommen getestet, als auch Modelle f{\"u}r Falter auf Heuschrecken {\"u}bertragen. Dabei erwiesen sich die Heuschreckenmodelle zur Prognose der anderen Arten weniger geeignet als das Modell f{\"u}r das Widderchen Z. carniolica in das der Anteil an geeignetem Habitat sowie die Vorkommen der beiden Saugpflanzen C. jacea und S. columbaria einfließen. Diese Art wird als standorttreu eingestuft und repr{\"a}sentiert damit auch die anderen Arten, die typisch f{\"u}r S{\"a}ume und Halbtrockenrasen sind. Die erh{\"o}hte Mobilit{\"a}t von Z. carniolica im Vergleich zu den Heuschrecken garantiert gleichzeitig auch die Erreichbarkeit aller geeigneten Fl{\"a}chen im Gebiet und damit ein Modell, das nur unwesentlich durch Zufallseffekte bei der Besiedlung beeinflusst wird. Neben der Habitatqualit{\"a}t/-quantit{\"a}t spielt vor allem der Austausch zwischen Fl{\"a}chen eine entscheidende Rolle f{\"u}r das {\"U}berleben der Metapopulation. Im zweiten Teil meiner Arbeit habe ich mich sowohl theoretisch als auch empirisch, mit dem Ausbreitungsverhalten von Heuschrecken besch{\"a}ftigt. In Freilandexperimenten konnte ich zeigen, dass die Annahme eines dichotomen Bewegungsverhaltens f{\"u}r Heuschrecken in einer realen Landschaft nicht zutrifft. Vielmehr wird die Bewegung in einer Fl{\"a}che besser als Kontinuum beschrieben das durch strukturelle Resistenz, Temperatur, Mortalit{\"a}tsrisiko und Ressourcenverf{\"u}gbarkeit bestimmt wird. Die jeweilige Kombination dieser Parameter veranlasst die Tiere dann zu einem entsprechenden Bewegungsmuster, das sich zwischen den beiden Extremen gerichteter und zuf{\"a}lliger Lauf bewegt. In Experimenten zum Grenzverhalten von Heuschrecken best{\"a}tigte sich dieses Ergebnis. F{\"u}r verschiedene Grenzstrukturen konnte ich unterschiedliche {\"U}bertrittswahrscheinlichkeiten nachweisen. Weiterhin konnte ich feststellen, dass Heuschrecken geeignete Habitate aus einer gewissen Entfernung detektieren k{\"o}nnen. Da das Ausbreitungsverhalten von Tieren in theoretischen Modellen eine wichtige Rolle spielt, k{\"o}nnen diese empirischen Daten zur Parametrisierung dieser Modelle verwendet werden. Zus{\"a}tzlich zum Einfluss des Laufmusters der Tiere auf die Erreichbarkeit geeigneter Habitate, zeigte sich in den von mir durchgef{\"u}hrten Simulationsstudien deutlich, dass der landschaftliche Kontext, in dem die Ausbreitung stattfindet, die Erreichbarkeit einzelner Habitate beeinflusst. Dieser Effekt ist zus{\"a}tzlich abh{\"a}ngig von der Mortalit{\"a}tsrate beim Ausbreitungsvorgang. Mit den Ergebnissen aus den Untersuchungen zur Habitateignung lassen sich die f{\"u}r Heuschrecken geeigneten Habitate in einer Landschaft identifizieren. Somit l{\"a}sst sich die potentielle Eignung einer Fl{\"a}che als Habitat, basierend auf Vorhersagen {\"u}ber die {\"A}nderung des Biotoptyps durch ein Managementverfahren, vorhersagen. Diese Information allein reicht aber nicht aus, um die regionale {\"U}berlebenswahrscheinlichkeit einer Art bestimmen zu k{\"o}nnen. Meine Untersuchungen zum Ausbreitungsverhalten zeigen deutlich, dass die Erreichbarkeit geeigneter Fl{\"a}chen von der r{\"a}umlichen Anordnung der Habitate und der Struktur der Fl{\"a}chen, die zwischen Habitaten liegen, abh{\"a}ngt. Zus{\"a}tzlich spielen individuenspezifische Faktoren wie Motivation und physiologische Faktoren eine ausschlaggebende Rolle f{\"u}r die Erreichbarkeit von geeigneten Fl{\"a}chen.}, subject = {Naturschutzgebiet Hohe Wann}, language = {en} }