scholarly journals Spatial Patterns in Plant Diversity

2021 ◽  
Author(s):  
◽  
Danilo Coelho de Almeida
Keyword(s):  
New Zealand ◽  
Plant Community ◽  
Plant Communities ◽  
Environmental Conditions ◽  
Species Abundance ◽  
Principal Component ◽  
Null Models ◽  
Individual Species ◽  
Leaf Mass Per Area ◽  
Mature Trees

<p>The present study is divided into two parts: Firstly, null models where used to test whether plant communities in a New Zealand forest were assembled deterministically or stochastically. Secondly, a relationship between a plant trait; Leaf Mass per Area (LMA) and environmental conditions was investigated in a New Zealand forest. For the first study abundance of adult species was recorded in thirty 30m x 30m plots at Otari Wilton's Bush. In a subsample of six plots, the abundance of seedling species was also recorded. Null models for species co-occurrence, species richness, species abundance and niche overlap were used in order to establish how plant communities assemble at Otari Wilton's Bush. There was evidence of both determinist and stochasticity in some aspects of the plant community, it appears that seedlings are mainly randomly assembled whereas, determinism appears to be the main driver of community composition for mature trees. Results therefore suggest a pluralistic approach should be used in order to explain plant community patterns at Otari Wilton's Bush. For the second study, of all species observed in the first study only those species found in five or more of the plots were examined. For those species, the height of the two highest individuals was measured. From each individual, six fully exposed leaves were collected and measured. Measurements of environmental conditions were also collected for all plots. Principal component analysis and multiple regression was used to analyse the data. Height related (vertical) trends were observed for three surveyed species such that LMA significantly increased with plant height. Horizontal patterns were observed for two species, and for three species it was not possible to distinguish the association of tree height (vertical) and position along the forest (horizontal) with LMA. Potentially, by including more species in future studies a clearer pattern will be observed. It could also be that different species display different strategies regarding LMA and if so, a study more focused on individual species in isolation may be able to provide more informative explanations.</p>

scholarly journals Spatial Patterns in Plant Diversity

2021 ◽  
Author(s):  
◽  
Danilo Coelho de Almeida
Keyword(s):  
New Zealand ◽  
Plant Community ◽  
Plant Communities ◽  
Environmental Conditions ◽  
Species Abundance ◽  
Principal Component ◽  
Null Models ◽  
Individual Species ◽  
Leaf Mass Per Area ◽  
Mature Trees

<p>The present study is divided into two parts: Firstly, null models where used to test whether plant communities in a New Zealand forest were assembled deterministically or stochastically. Secondly, a relationship between a plant trait; Leaf Mass per Area (LMA) and environmental conditions was investigated in a New Zealand forest. For the first study abundance of adult species was recorded in thirty 30m x 30m plots at Otari Wilton's Bush. In a subsample of six plots, the abundance of seedling species was also recorded. Null models for species co-occurrence, species richness, species abundance and niche overlap were used in order to establish how plant communities assemble at Otari Wilton's Bush. There was evidence of both determinist and stochasticity in some aspects of the plant community, it appears that seedlings are mainly randomly assembled whereas, determinism appears to be the main driver of community composition for mature trees. Results therefore suggest a pluralistic approach should be used in order to explain plant community patterns at Otari Wilton's Bush. For the second study, of all species observed in the first study only those species found in five or more of the plots were examined. For those species, the height of the two highest individuals was measured. From each individual, six fully exposed leaves were collected and measured. Measurements of environmental conditions were also collected for all plots. Principal component analysis and multiple regression was used to analyse the data. Height related (vertical) trends were observed for three surveyed species such that LMA significantly increased with plant height. Horizontal patterns were observed for two species, and for three species it was not possible to distinguish the association of tree height (vertical) and position along the forest (horizontal) with LMA. Potentially, by including more species in future studies a clearer pattern will be observed. It could also be that different species display different strategies regarding LMA and if so, a study more focused on individual species in isolation may be able to provide more informative explanations.</p>

scholarly journals Shifts in soil and plant functional diversity along an altitudinal gradient in the French Alps

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Alexia Stokes ◽  
Guillermo Angeles ◽  
Fabien Anthelme ◽  
Eduardo Aranda-Delgado ◽  
Isabelle Barois ◽  
...  
Keyword(s):  
Plant Community ◽  
Functional Diversity ◽  
Plant Communities ◽  
Species Abundance ◽  
Chemical Properties ◽  
Water Infiltration ◽  
Temperate Climate ◽  
Biophysical Properties ◽  
Tropical Zone ◽  
Soil Microbial

Abstract Objectives Altitude integrates changes in environmental conditions that determine shifts in vegetation, including temperature, precipitation, solar radiation and edaphogenetic processes. In turn, vegetation alters soil biophysical properties through litter input, root growth, microbial and macrofaunal interactions. The belowground traits of plant communities modify soil processes in different ways, but it is not known how root traits influence soil biota at the community level. We collected data to investigate how elevation affects belowground community traits and soil microbial and faunal communities. This dataset comprises data from a temperate climate in France and a twin study was performed in a tropical zone in Mexico. Data description The paper describes soil physical and chemical properties, climatic variables, plant community composition and species abundance, plant community traits, soil microbial functional diversity and macrofaunal abundance and diversity. Data are provided for six elevations (1400–2400 m) ranging from montane forest to alpine prairie. We focused on soil biophysical properties beneath three dominant plant species that structure local vegetation. These data are useful for understanding how shifts in vegetation communities affect belowground processes, such as water infiltration, soil aggregation and carbon storage. Data will also help researchers understand how plant communities adjust to a changing climate/environment.

scholarly journals Decline in New Zealand's freshwater fish fauna: Effect of land use

2020 ◽  
Author(s):  
Michael Joy ◽  
KJ Foote ◽  
P McNie ◽  
M Piria
Keyword(s):  
New Zealand ◽  
Land Cover ◽  
Freshwater Fish ◽  
Native Species ◽  
Species Abundance ◽  
Fish Fauna ◽  
Fish Distribution ◽  
Individual Species ◽  
Freshwater Fish Fauna ◽  
Over Time

© 2019 CSIRO. The number of New Zealand's freshwater fish listed as threatened has increased since 1992 when the first New Zealand threat classification system list was compiled. In this study, temporal and land cover-related trends were analysed for data on freshwater fish distribution, comprising more than 20 000 records for the 47 years from January 1970 to January 2017 from the New Zealand Freshwater Fish Database. The analysis included individual species abundance and distribution trends, as well as an index of fish community integrity, namely the Index of Biotic Integrity (IBI). Of the 25 fish species that met the requirements for analysis to determine changes in the proportion of sites they occupied over time, 76% had negative trends (indicating declining occurrence). Of the 20 native species analysed for the proportion of sites occupied over time, 75% had negative trends; 65% of these were significant declines and more species were in decline at pasture sites than natural cover sites. The average IBI score also declined over the time period and, when analysed separately, the major land cover types revealed that the IBI declined at pasture catchment sites but not at sites with natural vegetation catchments.

scholarly journals Plant communities as drivers of soil respiration: pathways, mechanisms, and significance for global change

2011 ◽  
Vol 8 (8) ◽  
pp. 2047-2061 ◽  
Author(s):  
D. B. Metcalfe ◽  
R. A. Fisher ◽  
D. A. Wardle
Keyword(s):  
Plant Community ◽  
Plant Communities ◽  
Plant Traits ◽  
Terrestrial Ecosystems ◽  
Climate Impacts ◽  
Individual Species ◽  
Global Changes ◽  
Individual Plant ◽  
Vegetation Types ◽  
Species Invasions

Abstract. Understanding the impacts of plant community characteristics on soil carbon dioxide efflux (R) is a key prerequisite for accurate prediction of the future carbon (C) balance of terrestrial ecosystems under climate change. However, developing a mechanistic understanding of the determinants of R is complicated by the presence of multiple different sources of respiratory C within soil – such as soil microbes, plant roots and their mycorrhizal symbionts – each with their distinct dynamics and drivers. In this review, we synthesize relevant information from a wide spectrum of sources to evaluate the current state of knowledge about plant community effects on R, examine how this information is incorporated into global climate models, and highlight priorities for future research. Despite often large variation amongst studies and methods, several general trends emerge. Mechanisms whereby plants affect R may be grouped into effects on belowground C allocation, aboveground litter properties and microclimate. Within vegetation types, the amount of C diverted belowground, and hence R, may be controlled mainly by the rate of photosynthetic C uptake, while amongst vegetation types this should be more dependent upon the specific C allocation strategies of the plant life form. We make the case that plant community composition, rather than diversity, is usually the dominant control on R in natural systems. Individual species impacts on R may be largest where the species accounts for most of the biomass in the ecosystem, has very distinct traits to the rest of the community and/or modulates the occurrence of major natural disturbances. We show that climate vegetation models incorporate a number of pathways whereby plants can affect R, but that simplifications regarding allocation schemes and drivers of litter decomposition may limit model accuracy. We also suggest that under a warmer future climate, many plant communities may shift towards dominance by fast growing plants which produce large quantities of nutrient rich litter. Where this community shift occurs, it could drive an increase in R beyond that expected from direct climate impacts on soil microbial activity alone. We identify key gaps in knowledge and recommend them as priorities for future work. These include the patterns of photosynthate partitioning amongst belowground components, ecosystem level effects of individual plant traits, and the importance of trophic interactions and species invasions or extinctions for ecosystem processes. A final, overarching challenge is how to link these observations and drivers across spatio-temporal scales to predict regional or global changes in R over long time periods. A more unified approach to understanding R, which integrates information about plant traits and community dynamics, will be essential for better understanding, simulating and predicting patterns of R across terrestrial ecosystems and its role within the earth-climate system.

Population ecology of Norway rats (Rattus norvegicus) and interference competition with Pacific rats (R. exulans) on Raoul Island, New Zealand

2006 ◽  
Vol 33 (7) ◽  
pp. 539 ◽  
Author(s):  
Grant Harper ◽  
Dick Veitch
Keyword(s):  
New Zealand ◽  
Population Ecology ◽  
Rattus Norvegicus ◽  
Interference Competition ◽  
Species Abundance ◽  
Late Summer ◽  
Baseline Data ◽  
Individual Species ◽  
Competitive Interference ◽  
Norway Rats

Norway rats (Rattus norvegicus) are sympatric with, and more often trapped, than the smaller Pacific rat (R. exulans) on Raoul Island, New Zealand. Rats were removed from a four-hectare grid by trapping and poisoning in the winters of 1994, 1995 and 1996. Pacific rats were trapped in increasing numbers only after Norway rats were removed. Norway rats also ate significantly more bait than Pacific rats. Competitive interference of Pacific rats by Norway rats was apparent, which casts doubt on the ability to accurately monitor individual species abundance within assemblages of rat species and to effectively manage them in control grids. Snap-trapping lines provided baseline data on the abundance of the two species before, during and after the removal grids were operated. Maximum abundances of rats were recorded in late summer and autumn following spring and summer breeding.

scholarly journals Decline in New Zealand's freshwater fish fauna: Effect of land use

2021 ◽  
Author(s):  
Michael Joy ◽  
KJ Foote ◽  
P McNie ◽  
M Piria
Keyword(s):  
New Zealand ◽  
Land Cover ◽  
Freshwater Fish ◽  
Native Species ◽  
Species Abundance ◽  
Fish Fauna ◽  
Fish Distribution ◽  
Individual Species ◽  
Freshwater Fish Fauna ◽  
Over Time

© 2019 CSIRO. The number of New Zealand's freshwater fish listed as threatened has increased since 1992 when the first New Zealand threat classification system list was compiled. In this study, temporal and land cover-related trends were analysed for data on freshwater fish distribution, comprising more than 20 000 records for the 47 years from January 1970 to January 2017 from the New Zealand Freshwater Fish Database. The analysis included individual species abundance and distribution trends, as well as an index of fish community integrity, namely the Index of Biotic Integrity (IBI). Of the 25 fish species that met the requirements for analysis to determine changes in the proportion of sites they occupied over time, 76% had negative trends (indicating declining occurrence). Of the 20 native species analysed for the proportion of sites occupied over time, 75% had negative trends; 65% of these were significant declines and more species were in decline at pasture sites than natural cover sites. The average IBI score also declined over the time period and, when analysed separately, the major land cover types revealed that the IBI declined at pasture catchment sites but not at sites with natural vegetation catchments.

scholarly journals Decline in New Zealand's freshwater fish fauna: Effect of land use

2020 ◽  
Author(s):  
Michael Joy ◽  
KJ Foote ◽  
P McNie ◽  
M Piria
Keyword(s):  
New Zealand ◽  
Land Cover ◽  
Freshwater Fish ◽  
Native Species ◽  
Species Abundance ◽  
Fish Fauna ◽  
Fish Distribution ◽  
Individual Species ◽  
Freshwater Fish Fauna ◽  
Over Time

© 2019 CSIRO. The number of New Zealand's freshwater fish listed as threatened has increased since 1992 when the first New Zealand threat classification system list was compiled. In this study, temporal and land cover-related trends were analysed for data on freshwater fish distribution, comprising more than 20 000 records for the 47 years from January 1970 to January 2017 from the New Zealand Freshwater Fish Database. The analysis included individual species abundance and distribution trends, as well as an index of fish community integrity, namely the Index of Biotic Integrity (IBI). Of the 25 fish species that met the requirements for analysis to determine changes in the proportion of sites they occupied over time, 76% had negative trends (indicating declining occurrence). Of the 20 native species analysed for the proportion of sites occupied over time, 75% had negative trends; 65% of these were significant declines and more species were in decline at pasture sites than natural cover sites. The average IBI score also declined over the time period and, when analysed separately, the major land cover types revealed that the IBI declined at pasture catchment sites but not at sites with natural vegetation catchments.

scholarly journals Decline in New Zealand's freshwater fish fauna: Effect of land use

2021 ◽  
Author(s):  
Michael Joy ◽  
KJ Foote ◽  
P McNie ◽  
M Piria
Keyword(s):  
New Zealand ◽  
Land Cover ◽  
Freshwater Fish ◽  
Native Species ◽  
Species Abundance ◽  
Fish Fauna ◽  
Fish Distribution ◽  
Individual Species ◽  
Freshwater Fish Fauna ◽  
Over Time

© 2019 CSIRO. The number of New Zealand's freshwater fish listed as threatened has increased since 1992 when the first New Zealand threat classification system list was compiled. In this study, temporal and land cover-related trends were analysed for data on freshwater fish distribution, comprising more than 20 000 records for the 47 years from January 1970 to January 2017 from the New Zealand Freshwater Fish Database. The analysis included individual species abundance and distribution trends, as well as an index of fish community integrity, namely the Index of Biotic Integrity (IBI). Of the 25 fish species that met the requirements for analysis to determine changes in the proportion of sites they occupied over time, 76% had negative trends (indicating declining occurrence). Of the 20 native species analysed for the proportion of sites occupied over time, 75% had negative trends; 65% of these were significant declines and more species were in decline at pasture sites than natural cover sites. The average IBI score also declined over the time period and, when analysed separately, the major land cover types revealed that the IBI declined at pasture catchment sites but not at sites with natural vegetation catchments.

scholarly journals Evaluating Biological Change in New Zealand Marine Reserves

2021 ◽  
Author(s):  
◽  
Anjali Pande
Keyword(s):  
New Zealand ◽  
Meta Analysis ◽  
Marine Reserves ◽  
Marine Reserve ◽  
Species Abundance ◽  
South Coast ◽  
Individual Species ◽  
The South ◽  
Key Species ◽  
And Control

<p>This study illustrates the importance of baseline surveys, why they are necessary and how best to conduct them. A proposed marine reserve site (the south coast of Wellington) was monitored for three years to establish a comprehensive baseline study. The results were used to recommend appropriate methodology for sampling in this area and also to establish which species are the best to use as indicator species to detect any possible change occurring in this area due to future reservation status. The 11 km stretch of coast surveyed, which included future reserve and control sites, was tested for heterogeneity, to prevent any future differences in sites being attributed to reservation status as opposed to natural variation. It was determined that an environmental gradient exists along the south coast, from east to west, most likely due to increasing wave exposure and increasingly strong tides and currents towards the west.  An established marine reserve (Kapiti Marine Reserve) was also monitored over the same period of time to establish what differences existed in size and abundance of key species between reserve and control sites. The data collected in this investigation were also compared to data collected immediately prior to reserve establishment to determine what changes had occurred over time. Results showed that sites inside the marine reserve supported a greater species abundance, and in some cases, larger size classes. There was some evidence for a general shift in the community structure particularly in algal plants. However, these results may have been confounded by the effect of one site that appeared to have a very high natural species diversity and abundance (even before reservation  status). It was concluded that the one-off survey conducted before establishment of this reserve was inadequate to use as a baseline against which to detect changes. No changes were found between the present study and the preliminary survey, although specific data analysis indicated a reserve effect. Continued sampling methodology for Kapiti Marine Reserve area was suggested. Raw data, on two key species (blue cod and rock lobster) from six marine reserves in New Zealand were investigated in an attempt to perform a statistical "meta-analysis" of the effects of marine reserves in New Zealand. A meta-analysis is different from a narrative review as it uses statistical methods to compare results across studies. This methodology has not been applied to studies of marine reserves before. The meta analysis conducted in the present investigation showed that generally marine reserves in New Zealand are having a positive effect, in terms of increasing size and abundance of individual species, as compared to control areas. There is some evidence for a latitudinal trend influencing the "effect size" (a statistical term indicating the magnitude of the treatment tested - in this case, reservation) of the reserves.</p>

scholarly journals Evaluating Biological Change in New Zealand Marine Reserves

2021 ◽  
Author(s):  
◽  
Anjali Pande
Keyword(s):  
New Zealand ◽  
Meta Analysis ◽  
Marine Reserves ◽  
Marine Reserve ◽  
Species Abundance ◽  
South Coast ◽  
Individual Species ◽  
The South ◽  
Key Species ◽  
And Control

<p>This study illustrates the importance of baseline surveys, why they are necessary and how best to conduct them. A proposed marine reserve site (the south coast of Wellington) was monitored for three years to establish a comprehensive baseline study. The results were used to recommend appropriate methodology for sampling in this area and also to establish which species are the best to use as indicator species to detect any possible change occurring in this area due to future reservation status. The 11 km stretch of coast surveyed, which included future reserve and control sites, was tested for heterogeneity, to prevent any future differences in sites being attributed to reservation status as opposed to natural variation. It was determined that an environmental gradient exists along the south coast, from east to west, most likely due to increasing wave exposure and increasingly strong tides and currents towards the west.  An established marine reserve (Kapiti Marine Reserve) was also monitored over the same period of time to establish what differences existed in size and abundance of key species between reserve and control sites. The data collected in this investigation were also compared to data collected immediately prior to reserve establishment to determine what changes had occurred over time. Results showed that sites inside the marine reserve supported a greater species abundance, and in some cases, larger size classes. There was some evidence for a general shift in the community structure particularly in algal plants. However, these results may have been confounded by the effect of one site that appeared to have a very high natural species diversity and abundance (even before reservation  status). It was concluded that the one-off survey conducted before establishment of this reserve was inadequate to use as a baseline against which to detect changes. No changes were found between the present study and the preliminary survey, although specific data analysis indicated a reserve effect. Continued sampling methodology for Kapiti Marine Reserve area was suggested. Raw data, on two key species (blue cod and rock lobster) from six marine reserves in New Zealand were investigated in an attempt to perform a statistical "meta-analysis" of the effects of marine reserves in New Zealand. A meta-analysis is different from a narrative review as it uses statistical methods to compare results across studies. This methodology has not been applied to studies of marine reserves before. The meta analysis conducted in the present investigation showed that generally marine reserves in New Zealand are having a positive effect, in terms of increasing size and abundance of individual species, as compared to control areas. There is some evidence for a latitudinal trend influencing the "effect size" (a statistical term indicating the magnitude of the treatment tested - in this case, reservation) of the reserves.</p>

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