title: The Brazilian freshwater wetscape: Changes in tree community diversity and composition on climatic and geographic gradients.
abstract: Wetlands harbor an important compliment of regional plant diversity, but in many regions data on wetland diversity and composition is still lacking, thus hindering our understanding of the processes that control it. While patterns of broad-scale terrestrial diversity and composition typically correlate with contemporary climate it is not clear to what extent patterns in wetlands are complimentary, or conflicting. To elucidate this, we consolidate data from wetland forest inventories in Brazil and examine patterns of diversity and composition along temperature and rainfall gradients spanning five biomes. We collated 196 floristic inventories covering an area >220 ha and including >260,000 woody individuals. We detected a total of 2,453 tree species, with the Amazon alone accounting for nearly half. Compositional patterns indicated differences in freshwater wetland floras among Brazilian biomes, although biomes with drier, more seasonal climates tended to have a larger proportion of more widely distributed species. Maximal alpha diversity increased with annual temperature, rainfall, and decreasing seasonality, patterns broadly consistent with upland vegetation communities. However, alpha diversity-climate relationships were only revealed at higher diversity values associated with the uppermost quantiles, and in most sites diversity varied irrespective of climate. Likewise, mean biome-level differences in alpha-diversity were unexpectedly modest, even in comparisons of savanna-area wetlands to those of nearby forested regions. We describe attenuated wetland climate-diversity relationships as a shifting balance of local and regional effects on species recruitment. Locally, excessive waterlogging strongly filters species able to colonize from regional pools. On the other hand, increased water availability can accommodate a rich community of drought-sensitive immigrant species that are able to track buffered wetland microclimates. We argue that environmental conditions in many wetlands are not homogeneous with respect to regional climate, and that responses of wetland tree communities to future climate change may lag behind that of non-wetland, terrestrial habitat.
authors.affiliation: Department of Floodplain Ecology, Institute of Geography and Geoecology, Karlsruhe Institute for Technology, Karlsruhe, Germany.|MAUA Working Group, Instituto Nacional de Pesquisas da Amazônia, Manaus, Amazonas, Brazil.
authors.forename: Florian
authors.initials: F
authors.lastname: Wittmann
authors.affiliation: Universidade Federal do Paraná, Curitiba, Paraná, Brazil.
authors.forename: Márcia C M
authors.initials: MC
authors.lastname: Marques
authors.affiliation: Universidade Federal do Mato Grosso do Sul, Campo Grande, Mato Grosso do Sul, Brazil.
authors.forename: Geraldo
authors.initials: G
authors.lastname: Damasceno Júnior
authors.affiliation: Universidade Regional Integrada do Alto Uruguai e das Missões, Erechim, Rio Grande do Sul, Brazil.
authors.forename: Jean Carlos
authors.initials: JC
authors.lastname: Budke
authors.affiliation: MAUA Working Group, Instituto Nacional de Pesquisas da Amazônia, Manaus, Amazonas, Brazil.
authors.forename: Maria T F
authors.initials: MT
authors.lastname: Piedade
authors.affiliation: Universidade Federal do Amazonas, Manaus, Amazonas, Brazil.
authors.forename: Astrid
authors.initials: A
authors.lastname: de Oliveira Wittmann
authors.affiliation: Confederación de Pueblos Indígenas de Bolivia, Gobernanza de Recursos Naturales, Santa Cruz de la Sierra, Santa Cruz, Bolivia.
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Montero
authors.affiliation: MAUA Working Group, Instituto Nacional de Pesquisas da Amazônia, Manaus, Amazonas, Brazil.|Norwegian University of Life Sciences, Ås, Akershus, Norway.
authors.forename: Rafael L
authors.initials: RL
authors.lastname: de Assis
authors.affiliation: MAUA Working Group, Instituto Nacional de Pesquisas da Amazônia, Manaus, Amazonas, Brazil.
authors.forename: Natália
authors.initials: N
authors.lastname: Targhetta
authors.affiliation: University of Hamburg, Biocentre Klein Flottbek, Department of Plant Diversity, Hamburg, Germany.
authors.forename: Pia
authors.initials: P
authors.lastname: Parolin
authors.affiliation: Instituto Nacional de Áreas Úmidas, Cuiabá, Mato Grosso, Brazil.
authors.forename: Wolfgang J
authors.initials: WJ
authors.lastname: Junk
authors.affiliation: Department of Floodplain Ecology, Institute of Geography and Geoecology, Karlsruhe Institute for Technology, Karlsruhe, Germany.|Botanical Research Institute of Texas, Fort Worth, Texas, United States of America.
authors.forename: J Ethan
authors.identifier: http://orcid.org/0000-0002-5959-3504
authors.initials: JE
authors.lastname: Householder
mesh_terms: D044822:Biodiversity; D001938:Brazil; D002980:Climate; D016000:Cluster Analysis; D065928:Forests; D005618:Fresh Water; D011891:Rain; D012044:Regression Analysis; D013696:Temperature; D014197:Trees; D053833:Wetlands