Dissertations / Theses on the topic 'Tropical Evergreen Forests'

Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第14669号
農博第1751号
新制||農||968(附属図書館)
学位論文||H21||N4442(農学部図書室)
UT51-2009-D381
京都大学大学院農学研究科森林科学専攻
(主査)教授 太田 誠一, 教授 谷 誠, 教授 舟川 晋也
学位規則第4条第1項該当

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1998.
Includes bibliographical references (p. 169-180).
by John J. Graham, Jr.
Ph.D.

Kyoto University (京都大学)
0048
新制・課程博士
博士(農学)
甲第8092号
農博第1088号
新制||農||795(附属図書館)
学位論文||H12||N3349(農学部図書室)
UT51-2000-C42
京都大学大学院農学研究科地域環境科学専攻
(主査)教授 武田 博清, 教授 東 順一, 教授 谷 誠
学位規則第4条第1項該当

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Conselho Nacional de Pesquisa e Desenvolvimento Cient?fico e Tecnol?gico - CNPq
Funda??o de Amparo ? Pesquisa do Estado da Bahia - FAPEB
(Effect of edge in structure, diversity and phenology in seasonal tropical forest submontane) Forest fragmentation causes physical and biological changes with habitat loss and insularization of populations, and the edge effect the most obvious consequence of this process. Thus, this study aimed to investigate the effect of linear edge in a fragment of submontane seasonal forest in the Chapada Diamantina, Bahia, Brazil (12?28'31 "S and 41?23'14''W) in order to analyze the structure and composition vegetation, reproductive phenology and the vegetative phenology, classifying the forest as their leaf pattern, and the functional diversity. Were marked 30 plots (10 x 10 m) random and 15 at the forest edge (0 - 100m) and 15 inside (> 150m) in the power line high voltage. For structural studies were marked all individuals with diameter at breast height ?5 cm. The species were classified according to successional category and phytosociological parameters were calculated and diversity indices. The Shannon - Wiener index was compared by t test Hutcheson and the other parameters by ANOVA. From this study the species with the highest importance value and abundance for the other investigations were chosen. In the reproductive phenological study monthly observations were made over 26 months in 481 individuals (282 on the edge (61 species) and 199 inside (50 species) of forest), recording the presence and absence of flowering (and flower button) and fruiting (immature and mature fruit) for all life forms. It is estimated timing, frequency and duration of phenological events and the species were classified as the pollination and dispersal syndromes. Data were analyzed with G test, linear regression and circular statistics. In the study of functional diversity created a matrix of functional traits to the edge and interior including phenological, structural and reproductive aspects. Measurements of leaf traits (thickness, dry dough sheet per unit area, juiciness, density, leaf area ratio and leaf mass fraction), density and wood water saturation were carried out in the dry and wet seasons (September / 2012 and January / 2013) in 20 species. Regressions were made between phenophases and environmental variables (precipitation, temperature, relative humidity, photoperiod and heat stroke), circular statistics and comparisons of leaf traits and wood density between the dry and rainy season through the G test and ANOVA. The species ordination in relation to leaf and wood attributes was evaluated by Principal Component Analysis (PCA). The functional groups were defined by cluster analysis with distance Gower and calculated indexes Functional richness (FRic), Functional divergence (FDiv), Functional evenness (FEve), Functional dispersion (FDis). ANOVA and linear regression were used to evaluate the rates between areas. In vegetative phenological study followed up the budding and leaf fall 350 individual trees in the community (39 species). Increase the impact of straight edge on the floristic composition was checked, the diversity and abundance of species, while less interference was observed in the tree community structure, as phytosociological parameters and ratios between the guilds did not differ significantly between edge and interior fragment. The phenological analysis revealed that flowering and fruiting at the edge and interior were continued for long, low-intensity periods, asynchronous and assazonal being for most phenophases, with a significant difference in the individual to button number. Seasonality in flowering and fruiting were observed for bush and grass land in both areas and epiphytes to the edge. Similar proportions in the number of species for pollination and dispersal syndromes were found on the edge and inside, with a predominance of melittophilous and animal dispersed species. The vegetation was evergreen, with budding and continuous leaf fall, low intensity and low sync. The leaf bud was related to rainfall and sunshine and fall with precipitation and humidity. Significant variation between the dry and wet seasons were observed in the proportion of saturated water in the wood, leaf area ratio and leaf succulence. ACP showed greater variance for wood density (88.7%) and stored water (11.3%), gathering most species with standard perenif?lios phenological and episodic perenif?lios, other attributes showed no relevance to the phenological patterns. The main functional groups formed on the edge and inside were similar, defined based on the way of life, stratum and pollination and dispersal. Of co-occurring species (40 species), 22.5% belong to different functional groups due to different growth patterns. The functional diversity indices showed higher mean values for the edge, except that Fric was higher in the forest. These were not affected by the distance to the edge. Changes were observed inside in relation to species richness and Shannon - Wiener only for Fric. The implementation of linear infrastructure brings similar impacts to those coming from other types of edges in community structure. In other aspects analyzed the changes were subtle for the tree community, but the same was not true for shrubs, herbs and vines. The vegetation can be classified as seasonal submontane rainforest always green, with small annual variation in the physiognomy of the vegetation, and the perenif?lios and perenif?lios types episodic predominant both in number of species and in their abundance. The leaf traits showed no relevance to phenology, not being good descriptors for the seasonal evergreen forest. There is no significant difference in functional diversity, but the highest rate obtained inside for functional wealth reflects the biological loss caused by the installation on the edge of the linear edge. Appearance evidenced by the greater abundance of Eschweilera tetrapetala Mori inside, an endemic species of submontane forests of the region. This study contributes to future conservation work to note the interference the linear edge on the forest ecosystem, as well as to the classification of the Brazilian forests, to verify the occurrence of seasonal evergreen forests in the Caatinga.
(Efeito de borda na estrutura, diversidade e fenologia de floresta tropical estacional submontana) A fragmenta??o florestal causa mudan?as f?sicas e biol?gicas com perda de habitat e insulariza??o das popula??es, sendo oefeito de borda a consequ?ncia mais evidente desse processo.Assim,objetivou-se investigar o efeito da borda linear em um fragmento de floresta estacional submontana na Chapada Diamantina, Bahia,Brasil (12?28?31??S e 41?23?14??W) com o intuito de analisar a estruturae a composi??o da vegeta??o, a fenologia reprodutivae a fenologia vegetativa, classificando a floresta quanto ao seu padr?o foliar, e a diversidade funcional. Foram marcadas 30 parcelas (10 x 10 m) aleat?rias sendo 15 na borda da floresta (0 - 100m) e 15 no seu interior (>150m) em rela??o ? rede el?trica de alta tens?o. Para o estudo estrutural foram marcados todos os indiv?duos com di?metro ? altura do peito ?5 cm. As esp?cies foram classificadas quanto ? categoria sucessional e foram calculados os par?metros fitossociol?gicos e ?ndices de diversidade. O ?ndice de Shannon - Wienerfoi comparado pelo teste t de Hutcheson e os demais par?metros pela ANOVA. A partir desse estudo foram escolhidas as esp?cies com maior valor de import?ncia e abundancia para as demais investiga??es.No estudo fenol?gico reprodutivo foram realizadas observa??es mensais durante 26 meses a 481 indiv?duos (282 na borda (61 esp?cies) e 199 no interior (50 esp?cies) da floresta), registrando-se a presen?a e aus?ncia de flora??o (bot?o e flor) e frutifica??o (frutos imaturo e maturo) para todas as formas de vida. Estimou-se sincronia, frequ?ncia e dura??o dos eventos fenol?gicos e as esp?cies foram classificadas quanto ?s s?ndromes de poliniza??o e dispers?o. Os dados foram analisados com teste G, regress?o linear e estat?stica circular. No estudo da diversidade funcional criou-se uma matriz de tra?os funcionais para a borda e interior incluindo aspectos fenol?gicos, estruturais e reprodutivos.Mensura??es de atributos foliares (espessura, massa seca de folha por unidade de ?rea, sucul?ncia, densidade, raz?o de ?rea foliar e fra??o de massa foliar), densidade e ?gua de satura??o da madeira foram realizadas nas esta??es seca e chuvosa (setembro/2012 e janeiro/2013) em 20 esp?cies. Foram feitas regress?es entre as fenofases e as vari?veis ambientais (precipita??o, temperatura, umidade relativa, fotoper?odo e insola??o), estat?stica circular e compara??es dos atributos foliares e densidade de madeira entre a esta??o seca e chuvosa atrav?s do teste G e ANOVA. A ordena??o das esp?cies em rela??o aos atributos foliares e de madeira foi avaliada pela An?lise do Componente Principal (ACP). Os grupos funcionais foram definidos por Cluster analysis com dist?ncia de Gower e calculados os ?ndices Functional richness (FRic), Functional divergence (FDiv), Functional evenness (FEve), Functional dispersion (FDis). ANOVA e regress?o linear foram usadas para avaliar os ?ndices entre ?reas. No estudo fenol?gico vegetativo acompanhou-se o brotamento e queda foliar de 350 indiv?duos arb?reos na comunidade (39 esp?cies). Foi verificado um maior impacto da borda linear sobre a composi??o flor?stica,a diversidade e abund?ncia das esp?cies, enquanto menor interfer?ncia foi verificada na estrutura da comunidade arb?rea, uma vez que par?metros fitossociol?gicos e propor??es entre as categorias sucessionais n?o diferiram significativamente entre borda e interior do fragmento.As an?lises fenol?gicas revelaram que a flora??o e frutifica??o na borda e interior foram cont?nuas por per?odos longos e com baixa intensidade, sendo assincr?nico e assazonal para a maioria das fenofases, com diferen?a significativa no n?mero de indiv?duo para bot?o.Sazonalidade na flora??o e frutifica??o foi observada para arbusto e erva terrestre em ambas as ?reas e ep?fitas para a borda.Propor??es semelhantes no n?mero de esp?cies por s?ndromes de poliniza??o e dispers?o foram encontradas na borda e no interior, com predomin?ncia de esp?cies melit?filas e zooc?ricas.A vegeta??o foi perenif?lia, com brotamento e queda foliar cont?nuos, baixa intensidade e baixa sincronia. O brotamento foliar relacionou-se com precipita??o e insola??o e a queda com precipita??o e umidade. Varia??o significativa entre as esta??es seca e chuvosa foram observadas na propor??o de ?gua saturada na madeira, raz?o de ?rea foliar e sucul?ncia da folha. ACP revelou maior varian?a para densidade da madeira (88,7%) e ?gua armazenada (11,3%), agrupando a maioria das esp?cies com padr?o fenol?gico perenif?lios e perenif?lios epis?dicos, os demais atributos n?o apresentaram relev?ncia em rela??o aos padr?es fenol?gicos. Os principais grupos funcionais formados na borda e no interior foram semelhantes, definidos com base na forma de vida, estrato e s?ndrome de poliniza??o e dispers?o. Das esp?cies co-ocorrentes (40 esp?cies), 22,5% pertencem a grupos funcionais distintos devido a diferentes padr?es fenol?gicos. Os ?ndices de diversidade funcional apresentaram valores m?dios superiores para a borda, exceto FRic que foi superior no interior da floresta. Estes n?o foram alterados pela dist?ncia com a borda. Altera??es foram observadas no interior em rela??o ? riqueza de esp?cie e ao ?ndice de Shannon - Wiener apenas para FRic.A implementa??o de infraestruturas lineares traz impactos semelhantes ?queles advindos de outros tipos de bordas na estrutura da comunidade. Nos demais aspectos analisados as varia??es foram sutis para a comunidade arb?rea, mas o mesmo n?o ocorreuem rela??o a arbustos, ervas e trepadeiras. A vegeta??o p?de ser classificada como floresta tropical estacional submontana sempre verde, com pequena varia??o anual na fisionomia da vegeta??o, sendo os tipos perenif?lios e perenif?lios epis?dicos predominantes tanto em n?mero de esp?cies quanto na sua abund?ncia. Os atributos foliares n?o apresentaram relev?ncia em rela??o aos padr?es fenol?gicos, n?o sendo bons descritores para a floresta estacional sempre verde. N?o h? diferen?a significativa na diversidade funcional, mas o maior ?ndice obtido no interior para a riqueza funcional reflete a perda biol?gica ocasionada na borda pela instala??o da borda linear.Aspecto evidenciado pela maior abund?ncia deEschweilera tetrapetala Mori no interior, esp?cie end?mica das florestas submontanas da regi?o. O presente estudo p?de contribuir com futuros trabalhos de conserva??o por constatar a interfer?ncia da borda linear no ecossistema florestal, bem como com a classifica??o das florestas brasileiras, ao verificar a ocorr?ncia de florestas estacional sempre verde no Bioma Caatinga.

Several animals, both vertebrate and invertebrate, communicate using sound and they do so in a non-ideal medium, the habitat in which they live. As acoustic signals pass through the habitat, they suffer loss of information due to signal degradation, which is often determined by the acoustic properties of the habitat. Understanding the influence of habitat-induced constraints on signaling is vital to the understanding of evolution of signal structure. Over time signals can evolve their temporal and/or spectral characteristics so as to resist or reduce degradation. Conversely, signalers may modify their behaviour so as to improve transmission for effective communication. The Acoustic Adaptation Hypothesis (AAH) predicts that given the properties of the habitat in which animals communicate, signals should evolve so as to maximize their broadcast range and the number of potential receivers. The prediction of the hypothesis is that signal transmission is best in the native habitat as compared to non-native habitats. Since its inception, the idea of acoustic adaptation has been tested in several vertebrate species including birds, mammals and frogs but rarely in invertebrates. Moreover, most of these studies have been carried out at the macrohabitat level, such as transmission in forests versus grasslands. For animals with limited mobility such as invertebrates, a finer level of investigation at the microhabitat level is more relevant. Only one study on cicadas has investigated the predictions of the AAH at the microhabitat level. Besides, investigations done at the community level are largely missing in the literature. The effect of height on signal transmission is well documented, however, only one study on birds has investigated the AAH with respect to vertical stratification of coexisting species. Among invertebrates, crickets are well known for their calling songs which males use to attract conspecific females over long distances. No study so far has tested the prediction of the AAH in these acoustically communicating invertebrates. The central focus of this study was to test the predictions of the AAH in a natural assemblage of ensiferan (cricket) species. I examined the prediction of the hypothesis at the microhabitat level with respect to the vertical stratification of co-existing ensiferan species. The study was carried out on an assemblage of crickets in the wet evergreen forests of Kudremukh National Park in the Western Ghats in Southern India. For this purpose, it was important to examine calling height and microhabitat selection in these animals because if the use of calling height and microhabitat was random, then there would not be any native height/microhabitat and the question of acoustic adaption would not arise. Therefore, I first standardized methods to characterize the habitat of the crickets. Using resource selection functions, I then quantified microhabitat selection in 13 ensiferan species. I also examined the calling heights of these species. My results suggest that these species are microhabitat specialists and also distribute vertically within the forest with respect to calling height. Based on the knowledge of the vertical distribution of these animals in the forest I then carried out playback experiments using natural calls of 12 species of Ensifera in their natural habitat. The transmission experiments were carried out at five heights in the forest, including the ground, different parts of the understorey as well as in the canopy. The study aimed to examine whether vertical stratification in the ensiferan species of Kudremukh is driven by selection for maximizing transmission range. I examined the effect of different heights on signal degradation. The investigation was carried out with respect to three different measures of signal degradation, namely, total attenuation, signal to noise ratio as well as envelope distortion. The results indicate a lack of overall support for the AAH with respect to vertical stratification of crickets in Kudremukh. However, a strong, independent effect of height of calling on signal degradation was found, with the ground being the worst layer for transmission and the mid-understorey (2 m) emerging to be good for all species with respect to all three measures of signal degradation. I then analysed the transmission data from a different point of view, exploring the possibility of evolution of signal structures that may confer some advantages in terms of signal transmission, given the habitat-induced constrains on signal propagation. The idea was to examine why certain species perform better than others in terms of signal transmission. This investigation was aimed at characterizing the effect of call features on signal attenuation. I found that temporal features of calls did not have a strong effect on height-specific signal attenuation. While call duration had no effect on signal attenuation, duty cycle did influence attenuation profiles of the calls, with high duty cycle calls performing better than low duty cycle calls. However, there was no interaction of height with the temporal features of calls, eliminating the possibility of these features being shaped by microhabitat or height dependent transmission characteristics. Spectral features of calls, on the other hand, affected signal attenuation very strongly. As expected, low frequency calls performed better than high frequency calls and pure tone calls fared much better than the broadband calls, especially on the ground and the canopy. To the best of my knowledge, this is the first study to carry out a rigorous quantification of microhabitat selection in Ensifera. This is also the first detailed examination of the Acoustic Adaptation Hypothesis at the microhabitat level, tested in a natural assemblage of coexisting invertebrate species.

Several animals, both vertebrate and invertebrate, communicate using sound and they do so in a non-ideal medium, the habitat in which they live. As acoustic signals pass through the habitat, they suffer loss of information due to signal degradation, which is often determined by the acoustic properties of the habitat. Understanding the influence of habitat-induced constraints on signaling is vital to the understanding of evolution of signal structure. Over time signals can evolve their temporal and/or spectral characteristics so as to resist or reduce degradation. Conversely, signalers may modify their behaviour so as to improve transmission for effective communication. The Acoustic Adaptation Hypothesis (AAH) predicts that given the properties of the habitat in which animals communicate, signals should evolve so as to maximize their broadcast range and the number of potential receivers. The prediction of the hypothesis is that signal transmission is best in the native habitat as compared to non-native habitats. Since its inception, the idea of acoustic adaptation has been tested in several vertebrate species including birds, mammals and frogs but rarely in invertebrates. Moreover, most of these studies have been carried out at the macrohabitat level, such as transmission in forests versus grasslands. For animals with limited mobility such as invertebrates, a finer level of investigation at the microhabitat level is more relevant. Only one study on cicadas has investigated the predictions of the AAH at the microhabitat level. Besides, investigations done at the community level are largely missing in the literature. The effect of height on signal transmission is well documented, however, only one study on birds has investigated the AAH with respect to vertical stratification of coexisting species. Among invertebrates, crickets are well known for their calling songs which males use to attract conspecific females over long distances. No study so far has tested the prediction of the AAH in these acoustically communicating invertebrates. The central focus of this study was to test the predictions of the AAH in a natural assemblage of ensiferan (cricket) species. I examined the prediction of the hypothesis at the microhabitat level with respect to the vertical stratification of co-existing ensiferan species. The study was carried out on an assemblage of crickets in the wet evergreen forests of Kudremukh National Park in the Western Ghats in Southern India. For this purpose, it was important to examine calling height and microhabitat selection in these animals because if the use of calling height and microhabitat was random, then there would not be any native height/microhabitat and the question of acoustic adaption would not arise. Therefore, I first standardized methods to characterize the habitat of the crickets. Using resource selection functions, I then quantified microhabitat selection in 13 ensiferan species. I also examined the calling heights of these species. My results suggest that these species are microhabitat specialists and also distribute vertically within the forest with respect to calling height. Based on the knowledge of the vertical distribution of these animals in the forest I then carried out playback experiments using natural calls of 12 species of Ensifera in their natural habitat. The transmission experiments were carried out at five heights in the forest, including the ground, different parts of the understorey as well as in the canopy. The study aimed to examine whether vertical stratification in the ensiferan species of Kudremukh is driven by selection for maximizing transmission range. I examined the effect of different heights on signal degradation. The investigation was carried out with respect to three different measures of signal degradation, namely, total attenuation, signal to noise ratio as well as envelope distortion. The results indicate a lack of overall support for the AAH with respect to vertical stratification of crickets in Kudremukh. However, a strong, independent effect of height of calling on signal degradation was found, with the ground being the worst layer for transmission and the mid-understorey (2 m) emerging to be good for all species with respect to all three measures of signal degradation. I then analysed the transmission data from a different point of view, exploring the possibility of evolution of signal structures that may confer some advantages in terms of signal transmission, given the habitat-induced constrains on signal propagation. The idea was to examine why certain species perform better than others in terms of signal transmission. This investigation was aimed at characterizing the effect of call features on signal attenuation. I found that temporal features of calls did not have a strong effect on height-specific signal attenuation. While call duration had no effect on signal attenuation, duty cycle did influence attenuation profiles of the calls, with high duty cycle calls performing better than low duty cycle calls. However, there was no interaction of height with the temporal features of calls, eliminating the possibility of these features being shaped by microhabitat or height dependent transmission characteristics. Spectral features of calls, on the other hand, affected signal attenuation very strongly. As expected, low frequency calls performed better than high frequency calls and pure tone calls fared much better than the broadband calls, especially on the ground and the canopy. To the best of my knowledge, this is the first study to carry out a rigorous quantification of microhabitat selection in Ensifera. This is also the first detailed examination of the Acoustic Adaptation Hypothesis at the microhabitat level, tested in a natural assemblage of coexisting invertebrate species.

It has been more than two centuries since the latitudinal pattern of increase in taxonomic richness from poles to equator was first documented. After two centuries of research, and with more than two dozen hypotheses proposed, an understanding of the mechanisms underlying this pattern and their relative importance remains incomplete. Factors such as evolutionary history, area and latitude associated variables such as temperature, solar energy, climatic stability and seasonality are known to influence species richness by affecting geographic range size and location over ecological and evolutionary time. Understanding the forces that affect geographic range size is, therefore, integral to our understanding of latitudinal patterns in species richness. Using woody plants as a study system, my dissertation deciphers the latitudinal pattern, if any, in species richness within the evergreen forests of the Western Ghats. These wet evergreen forests form an evolutionarily distinct biogeographic zone, which has remained isolated from its counterparts. This has resulted in a high percentage of endemism among the evergreen woody plants and, therefore, the global geographic ranges of most of these plants are restricted within the boundaries of the Western Ghats. The first main objective of this dissertation is to understand the determinants of geographic range size in the evergreen woody plants of the Western Ghats. Further, the Western Ghats are characterized by a sharp climatic gradient in temperature and rainfall seasonality that is not correlated with mean annual temperature or annual rainfall. This allows a direct test of the hypotheses and predictions that are based on climatic seasonality, without the confounding effect of other climatic correlates of latitude. Therefore, the second main objective of this dissertation is to understand the mechanisms underlying latitudinal patterns in species richness of evergreen woody plants in the Western Ghats. Regional species richness is an outcome of two factors- local species richness of each location within the region and turnover in species composition among the locations, which in turn are a result of patterns in range size, range location and range overlap. To address these two objectives, I first test the effect of climatic niche of a species in determining geographic range size and then examine the effect of latitude associated climatic seasonality on range location and range overlap. Next, I link the observed pattern in range geometry to latitudinal patterns in species turnover and finally to latitudinal patterns in species richness. While the first part of my dissertation study deals with factors that generate spatial variation in species richness, the second part deals with the factors underlying spatial variation in species composition. Environmental heterogeneity and dispersal are considered the most important determinants of species turnover i.e. change in species composition. However, their relative importance in structuring in diverse plant communities within tropical regions across different scales is poorly understood. Hence, the third objective of this dissertation is to understand the processes that influence change in species composition of woody plants within the Western Ghats. Geographic range size and population size are important attributes of species rarity, which are directly linked to their extinction risk. Hence, data on distribution and population status of species can help us focus our efforts on those species that require conservation attention. This is achieved through carrying out species threat assessments based on attributes such as range and population size and then assigning then to a threat category. A majority of species endemic to the Western Ghats have not yet been assessed, largely due to lack of data on their population and distribution status. Therefore, the fourth and the final part of my dissertation explores the application of information on species range size and abundance in prioritizing species for conservation. To address these objectives, I sampled the wet evergreen forests of the Western Ghats along a series of locations distributed across its entire latitudinal gradient. Based on 156 plots, covering a latitudinal gradient of more than 1200 km and comprising of more than 20,000 occurrence locations belonging to more than 450 species of woody plants, I derived quantitative estimates of latitudinal gradients in range size, local and regional richness as well as species turnover. I used a combination of statistical and simulation approaches to discern the mechanisms underlying large-scale pattern in species ranges, richness and turnover. My dissertation is structured as follows.

It has been more than two centuries since the latitudinal pattern of increase in taxonomic richness from poles to equator was first documented. After two centuries of research, and with more than two dozen hypotheses proposed, an understanding of the mechanisms underlying this pattern and their relative importance remains incomplete. Factors such as evolutionary history, area and latitude associated variables such as temperature, solar energy, climatic stability and seasonality are known to influence species richness by affecting geographic range size and location over ecological and evolutionary time. Understanding the forces that affect geographic range size is, therefore, integral to our understanding of latitudinal patterns in species richness. Using woody plants as a study system, my dissertation deciphers the latitudinal pattern, if any, in species richness within the evergreen forests of the Western Ghats. These wet evergreen forests form an evolutionarily distinct biogeographic zone, which has remained isolated from its counterparts. This has resulted in a high percentage of endemism among the evergreen woody plants and, therefore, the global geographic ranges of most of these plants are restricted within the boundaries of the Western Ghats. The first main objective of this dissertation is to understand the determinants of geographic range size in the evergreen woody plants of the Western Ghats. Further, the Western Ghats are characterized by a sharp climatic gradient in temperature and rainfall seasonality that is not correlated with mean annual temperature or annual rainfall. This allows a direct test of the hypotheses and predictions that are based on climatic seasonality, without the confounding effect of other climatic correlates of latitude. Therefore, the second main objective of this dissertation is to understand the mechanisms underlying latitudinal patterns in species richness of evergreen woody plants in the Western Ghats. Regional species richness is an outcome of two factors- local species richness of each location within the region and turnover in species composition among the locations, which in turn are a result of patterns in range size, range location and range overlap. To address these two objectives, I first test the effect of climatic niche of a species in determining geographic range size and then examine the effect of latitude associated climatic seasonality on range location and range overlap. Next, I link the observed pattern in range geometry to latitudinal patterns in species turnover and finally to latitudinal patterns in species richness. While the first part of my dissertation study deals with factors that generate spatial variation in species richness, the second part deals with the factors underlying spatial variation in species composition. Environmental heterogeneity and dispersal are considered the most important determinants of species turnover i.e. change in species composition. However, their relative importance in structuring in diverse plant communities within tropical regions across different scales is poorly understood. Hence, the third objective of this dissertation is to understand the processes that influence change in species composition of woody plants within the Western Ghats. Geographic range size and population size are important attributes of species rarity, which are directly linked to their extinction risk. Hence, data on distribution and population status of species can help us focus our efforts on those species that require conservation attention. This is achieved through carrying out species threat assessments based on attributes such as range and population size and then assigning then to a threat category. A majority of species endemic to the Western Ghats have not yet been assessed, largely due to lack of data on their population and distribution status. Therefore, the fourth and the final part of my dissertation explores the application of information on species range size and abundance in prioritizing species for conservation. To address these objectives, I sampled the wet evergreen forests of the Western Ghats along a series of locations distributed across its entire latitudinal gradient. Based on 156 plots, covering a latitudinal gradient of more than 1200 km and comprising of more than 20,000 occurrence locations belonging to more than 450 species of woody plants, I derived quantitative estimates of latitudinal gradients in range size, local and regional richness as well as species turnover. I used a combination of statistical and simulation approaches to discern the mechanisms underlying large-scale pattern in species ranges, richness and turnover. My dissertation is structured as follows.

The present study provides the first description of the calls of a multi-species ensiferan assemblage in a tropical evergreen forest of the Indian subcontinent. I have identified and described the calls of twenty ensiferan species constituting the nocturnal acoustic community of a tropical evergreen forest in KNP. I found that the multi-species ensiferan assemblage consisted of diverse taxa representing subfamilies of the families Gryllidae, Tettigoniidae and Anostostomatidae. Eight acoustically communicating species of the family Gryllidae were found. Two species belonged to the family Mogoplistidae. Interestingly, each subfamily was mostly represented by only one genus. In the tettigoniids, representative species were found only from subfamilies Pseudophyllinae, Phaneropterinae and Mecopodinae. The species richness of the acoustically communicating cricket assemblage in the tropical evergreen forest of Kudremukh was found to be low. This study did not include non-calling and ultrasonic species of crickets. The gryllid and tettigoniid species analyzed exhibited different frequency (both narrow and broadband) and temporal patterns. Species belonging to the family Gryllidae had narrow band calls (with bandwidths not greater than 1 kHz) and had dominant frequencies mainly between 3 and 7 kHz. The calls of tettigoniids covered a wide spectral range reaching far into the ultrasound in species of the genus Mecopoda. Interestingly, of nine tettigoniid species, the calls of four (Onomarchus sp., Phyllomimus sp., Brochopeplus sp. and ‘15 kHz’) were narrow band and in the audible range, similar to those of gryllids. Although there was a high overlap of call frequencies between 3 to 7 kHz, gryllid species separated in their syllable repetition rate, which varied from six syllables per second in Landreva to 60 syllables/second in Gryllitara. Species with overlapping syllable repetition rates of 10 – 20 syllables per second separated along the frequency axis. There were species such as those of Phaloria and Gryllitara, Scapsipedus, Xabea and Callogryllus that overlapped both in the spectral and syllable repetition rates. These species however, differed in the other temporal features such as call duration, call period and number of syllables per call. This study also provides the first description of the calls and stridulatory structures of an Indian weta species (Family Anostostomatidae). Both males and females of this species were found to stridulate. The calls of the two sexes had similar spectral features. Male calls consisted of four syllables each, while female calls were bisyllabic. Stridulatory structures were similar between the sexes. I also quantitatively validated the reliability of human listener - based psychoacoustic sampling as a technique to monitor species richness and relative abundance of acoustically communicating ensiferan species that are within the human hearing range. I have shown using controlled psychoacoustic tests in the laboratory that a trained listener is capable of identifying the species as well as the number of individuals of Ensifera with high accuracy. This study suggests that trained listener - based psychoacoustic sampling may be preferable to carry out rapid assessments and species inventories of gryllids and low frequency katydid species in tropical forests. My study also suggests that acoustic monitoring of Orthoptera should be done using both the trained listener - based spot sampling and ambient noise recordings using ultrasound detectors for accurately estimating species richness and relative abundance in an area. Using focal animal sampling, I have shown that most species in the tropical forest ensiferan assemblage of Kudremukh National Park did not move more than a metre in a span of half an hour. The acoustic sampling should be designed in such a way as to cause minimal disturbance to the calling animals and could be limited to ten minutes to avoid re-counting individuals and counter the problem of pseudoreplication. I also investigated the spatial dispersion of calling sites in the vertical dimension. This study revealed vertical stratification of the calling heights of the twenty ensiferan species. Calling heights of both gryllid and tettigoniid species ranged from the ground to the canopy, although more gryllid than tettigoniid species occupied the ground and herb layer. Post hoc comparisons and cluster analysis indicated the presence of discrete calling height layers corresponding to the canopy, understorey, herb and ground layer. These clusters emerged from the raw data of calling heights of individuals of each species without a priori distinction of layers. This is in contrast to other studies on vertical stratification in arthropods and bats where baits, traps and mist nets are placed at different vertical layers, thereby demarcating the layers beforehand. Previous studies on crickets, cicadas and frogs have shown preference for the height of calling sites qualitatively. To my knowledge, this is the first study to quantitatively establish vertical stratification in calling heights in an ensiferan assemblage of an evergreen forest. No correlation between the calling heights and mean dominant frequencies of the species were found. Cricket species with relatively low frequency calls (3–4 kHz) occupied both the ground layer (Callogryllus sp. and Scapsipedus sp.) and the canopy (Xabea sp. and Onomarchus sp) suggesting that these narrow-band, relatively low frequency signals may be optimal for sound transmission in the cluttered habitat of the forest floor (due to leaf litter) and the canopy (due to high leaf density). Species with high frequencies such as Brochopeplus sp. and ‘15 kHz’ called mainly from vegetation in the understorey. Species with broadband calls (Mecopoda sp., Pirmeda sp. and Elimaea sp.) called just above the ground layer and from the understorey suggesting that calls with higher frequencies and bandwidths may be used in the somewhat less-cluttered microhabitat of the understorey. Calling height stratification in the ensiferan assemblages of tropical forests could also be due to other ecological factors such as predation by spiders, mantises, bats, birds or primates. The wide range of duty cycles, presence of high duty cycle callers (such as Mecopoda) and the lack of correlation of duty cycle with calling height found in our study site are interesting. Studies on acoustic transmission in different microhabitats at different heights and on predation pressure on the ensiferan species will provide further insight into the selective forces influencing calling height stratification. The multi-species assemblage constituting the nocturnal acoustic community was found to be calling in the same time period between evening to midnight and no species was found to have a unique calling time that is different from that of another species. There was no diel partitioning of calling time between the acoustically communicating ensiferan species. Frogs and cicadas that can be considered as acoustic competitors of the ensiferan assemblage appeared to be separating from crickets on a seasonal and diel scale respectively. This study has quantified the amount of masking interference in three dimensions viz. temporal, fine temporal and spectral, between sixteen species belonging to the nocturnal acoustic ensiferan assemblage of an evergreen forest. Frequency histograms of overlap, bar graphs of overlap on a species by other species and Mantel’s test results on matrix correlation suggest negative relations between the temporal, fine-temporal and spectral overlaps. Species with high overlap in one dimension had very low levels of overlap in any of the other two dimensions, suggesting acoustic resource partitioning in the ensiferan assemblage of the evergreen forest. I also tried to quantify the extent of spatial overlap between species based on calling intensity and inter-specific distances. However, spatial overlap could not be analysed further as there were some species pairs for which I did not have the inter-individual distances despite carrying out the field work for six months. The procedure of estimating spatial overlap between species pairs and the result along with missing gaps is presented in appendix 2. It will be interesting to investigate the extent of spatial overlap between species pairs as the fourth dimension in which species could separate to avoid acoustic competition. It is also important to estimate the relative abundance of species in the evergreen forest to obtain a realistic representation of masking interference between species. Partitioning of acoustic resources among ensiferan assemblage could also be better explained by analysing all the dimensions.

The present study provides the first description of the calls of a multi-species ensiferan assemblage in a tropical evergreen forest of the Indian subcontinent. I have identified and described the calls of twenty ensiferan species constituting the nocturnal acoustic community of a tropical evergreen forest in KNP. I found that the multi-species ensiferan assemblage consisted of diverse taxa representing subfamilies of the families Gryllidae, Tettigoniidae and Anostostomatidae. Eight acoustically communicating species of the family Gryllidae were found. Two species belonged to the family Mogoplistidae. Interestingly, each subfamily was mostly represented by only one genus. In the tettigoniids, representative species were found only from subfamilies Pseudophyllinae, Phaneropterinae and Mecopodinae. The species richness of the acoustically communicating cricket assemblage in the tropical evergreen forest of Kudremukh was found to be low. This study did not include non-calling and ultrasonic species of crickets. The gryllid and tettigoniid species analyzed exhibited different frequency (both narrow and broadband) and temporal patterns. Species belonging to the family Gryllidae had narrow band calls (with bandwidths not greater than 1 kHz) and had dominant frequencies mainly between 3 and 7 kHz. The calls of tettigoniids covered a wide spectral range reaching far into the ultrasound in species of the genus Mecopoda. Interestingly, of nine tettigoniid species, the calls of four (Onomarchus sp., Phyllomimus sp., Brochopeplus sp. and ‘15 kHz’) were narrow band and in the audible range, similar to those of gryllids. Although there was a high overlap of call frequencies between 3 to 7 kHz, gryllid species separated in their syllable repetition rate, which varied from six syllables per second in Landreva to 60 syllables/second in Gryllitara. Species with overlapping syllable repetition rates of 10 – 20 syllables per second separated along the frequency axis. There were species such as those of Phaloria and Gryllitara, Scapsipedus, Xabea and Callogryllus that overlapped both in the spectral and syllable repetition rates. These species however, differed in the other temporal features such as call duration, call period and number of syllables per call. This study also provides the first description of the calls and stridulatory structures of an Indian weta species (Family Anostostomatidae). Both males and females of this species were found to stridulate. The calls of the two sexes had similar spectral features. Male calls consisted of four syllables each, while female calls were bisyllabic. Stridulatory structures were similar between the sexes. I also quantitatively validated the reliability of human listener - based psychoacoustic sampling as a technique to monitor species richness and relative abundance of acoustically communicating ensiferan species that are within the human hearing range. I have shown using controlled psychoacoustic tests in the laboratory that a trained listener is capable of identifying the species as well as the number of individuals of Ensifera with high accuracy. This study suggests that trained listener - based psychoacoustic sampling may be preferable to carry out rapid assessments and species inventories of gryllids and low frequency katydid species in tropical forests. My study also suggests that acoustic monitoring of Orthoptera should be done using both the trained listener - based spot sampling and ambient noise recordings using ultrasound detectors for accurately estimating species richness and relative abundance in an area. Using focal animal sampling, I have shown that most species in the tropical forest ensiferan assemblage of Kudremukh National Park did not move more than a metre in a span of half an hour. The acoustic sampling should be designed in such a way as to cause minimal disturbance to the calling animals and could be limited to ten minutes to avoid re-counting individuals and counter the problem of pseudoreplication. I also investigated the spatial dispersion of calling sites in the vertical dimension. This study revealed vertical stratification of the calling heights of the twenty ensiferan species. Calling heights of both gryllid and tettigoniid species ranged from the ground to the canopy, although more gryllid than tettigoniid species occupied the ground and herb layer. Post hoc comparisons and cluster analysis indicated the presence of discrete calling height layers corresponding to the canopy, understorey, herb and ground layer. These clusters emerged from the raw data of calling heights of individuals of each species without a priori distinction of layers. This is in contrast to other studies on vertical stratification in arthropods and bats where baits, traps and mist nets are placed at different vertical layers, thereby demarcating the layers beforehand. Previous studies on crickets, cicadas and frogs have shown preference for the height of calling sites qualitatively. To my knowledge, this is the first study to quantitatively establish vertical stratification in calling heights in an ensiferan assemblage of an evergreen forest. No correlation between the calling heights and mean dominant frequencies of the species were found. Cricket species with relatively low frequency calls (3–4 kHz) occupied both the ground layer (Callogryllus sp. and Scapsipedus sp.) and the canopy (Xabea sp. and Onomarchus sp) suggesting that these narrow-band, relatively low frequency signals may be optimal for sound transmission in the cluttered habitat of the forest floor (due to leaf litter) and the canopy (due to high leaf density). Species with high frequencies such as Brochopeplus sp. and ‘15 kHz’ called mainly from vegetation in the understorey. Species with broadband calls (Mecopoda sp., Pirmeda sp. and Elimaea sp.) called just above the ground layer and from the understorey suggesting that calls with higher frequencies and bandwidths may be used in the somewhat less-cluttered microhabitat of the understorey. Calling height stratification in the ensiferan assemblages of tropical forests could also be due to other ecological factors such as predation by spiders, mantises, bats, birds or primates. The wide range of duty cycles, presence of high duty cycle callers (such as Mecopoda) and the lack of correlation of duty cycle with calling height found in our study site are interesting. Studies on acoustic transmission in different microhabitats at different heights and on predation pressure on the ensiferan species will provide further insight into the selective forces influencing calling height stratification. The multi-species assemblage constituting the nocturnal acoustic community was found to be calling in the same time period between evening to midnight and no species was found to have a unique calling time that is different from that of another species. There was no diel partitioning of calling time between the acoustically communicating ensiferan species. Frogs and cicadas that can be considered as acoustic competitors of the ensiferan assemblage appeared to be separating from crickets on a seasonal and diel scale respectively. This study has quantified the amount of masking interference in three dimensions viz. temporal, fine temporal and spectral, between sixteen species belonging to the nocturnal acoustic ensiferan assemblage of an evergreen forest. Frequency histograms of overlap, bar graphs of overlap on a species by other species and Mantel’s test results on matrix correlation suggest negative relations between the temporal, fine-temporal and spectral overlaps. Species with high overlap in one dimension had very low levels of overlap in any of the other two dimensions, suggesting acoustic resource partitioning in the ensiferan assemblage of the evergreen forest. I also tried to quantify the extent of spatial overlap between species based on calling intensity and inter-specific distances. However, spatial overlap could not be analysed further as there were some species pairs for which I did not have the inter-individual distances despite carrying out the field work for six months. The procedure of estimating spatial overlap between species pairs and the result along with missing gaps is presented in appendix 2. It will be interesting to investigate the extent of spatial overlap between species pairs as the fourth dimension in which species could separate to avoid acoustic competition. It is also important to estimate the relative abundance of species in the evergreen forest to obtain a realistic representation of masking interference between species. Partitioning of acoustic resources among ensiferan assemblage could also be better explained by analysing all the dimensions.

In recent years landscape-scale fires have occurred in mainland Southeast Asia, including important protected areas (PAs). There has been increasing concern that landscape-scale fires are degrading the seasonally dry evergreen forest (SEF) element of the forest mosaic to more open deciduous forest and savanna, with serious implications for biodiversity conservation. Present management approaches, including fire suppression and prescribed burning, have not been effective managing for landscape-scale fire. Research was undertaken to investigate the occurrence, cause, effect, frequency and predictability of fire in SEF. SEF has the greatest species biodiversity in the forest mosaic and is potentially the most affected by fire, yet little research has been done on fire in SEF in mainland Southeast Asia. Huai Kha Khaeng (HKK) Wildlife Sanctuary in Thailand was selected as the study area. The objectives included: 1) investigate the area of SEF burned in HKK from 1988 to 2002; 2) investigate the conditions for fire in SEF; 3) determine whether the area of SEF in HKK declined as a result of fire; 4) determine the frequency of fire season years between 1984 and 2001 with the conditions for fire spread in SEF; and 5) determine whether there is a significant relationship between pre-fire season drought codes (Keetch-Byram Drought Index (KBDI) and Canadian Drought Code (DC)) and identified SEF fire season years for 1981 to 2003. Methods included: development of a Landsat fire history with associated interviews and reconnaissance field checks; fieldwork lighting test fires and measuring fuel characteristics; remote sensing change detection work using Landsat imagery; generation of a twenty-one year daily relative humidity minimum record for SEF; and logistic regression of the pre-fire season drought code values with identified SEF ‘fire’ and ‘non-fire’ years. Results showed: 1. Extensive areas of SEF have burned, but that Landsat imagery was not suitable for detecting fire in intact SEF. 2. SEF burned in years when there were fires burning adjacent to SEF in mid March and the moisture content of the SEF leaf litter fuel was less than 15%. 3. Fifteen percent of SEF in HKK has been either degraded or converted to deciduous forest forms in 12 years. 4. Conditions for fire spread in SEF occurred four times in 17 consecutive years. 5. A significant relationship exists between both the Keetch-Byram Drought Code (KBDI) and Canadian Drought Code (DC) and the SEF fire years. Implications are that large-scale fires have adversely affected intact SEF in HKK, and that the current damaging situation can be expected to continue. Whereas the extent of burning in intact SEF is not known, the need to manage the situation is immediate. Landscape-scale fires in HKK can be managed by using January 31st drought code values to predict potential large-scale fire years, followed by an aggressive fire suppression campaign in those years. In other years, fires can be allowed to burn without serious threat to the forest mosaic, and should to some extent be encouraged to maintain open deciduous forests and savanna. Additional research is required to determine whether a similar approach can be used for protected areas in other parts of the region.