scholarly journals Are eucalypts Brazil's friend or foe? An entomological viewpoint

1999 ◽  
Vol 28 (2) ◽  
pp. 185-200 ◽  
Author(s):  
Jonathan D. Majer ◽  
Harry F. Recher

Vast areas of Brazil are being planted to Eucalyptus in order to provide renewable sources of timber, charcoal and cellulose. Although the rapid growth and productivity of various Eucalyptus species undoubtedly relaxes the pressure on logging of native forests, there are ecological costs. Firstly, some eucalypt species are vulnerable to pest outbreaks. A large number of native Lepidoptera, Coleoptera and leaf-cutting ants (Atta spp.), some of which have become pests, have been found on eucalypts growing in Brazil. Probably, the diverse myrtaceous flora of South America supports a fauna that can adapt to the introduced Eucalyptus species. Secondly, the leaf litter produced under Eucalyptus plantations differs substantially from that of native forests both in terms of its physical structure and chemistry, posing a range of problems for the native decomposer fauna. If microarthropod diversity is reduced, nutrient cycling could be impeded under eucalypt plantations. Thirdly, native forest canopies support a massive diversity and biomass of arthropods on which many birds, reptiles and mammals depend for food. The evidence is that invertebrate biomass and diversity are greatly reduced in the canopies of exotic eucalypt plantations. This, in turn, reduces the food-base on which forest arthropods and other animals depend, and hence their conservation status. This paper reviews the evidence for adverse ecological effects in Brazilian eucalypt plantations and suggests ways in which Brazil might meet its forestry needs, while conserving forest invertebrates and the vertebrates that depend on them.

2003 ◽  
Vol 93 (2) ◽  
pp. 137-144 ◽  
Author(s):  
H.F. Nahrung ◽  
G.R. Allen

AbstractChrysophtharta agricola (Chapuis) is a pest of commercial eucalypt plantations in Tasmania and Victoria. Vagility of pest populations may result in difficulty predicting temporal and spatial pest outbreaks, and influence genetic resistance to chemical control. Gene flow in this pest species was estimated to assess predicability of attack, the potential efficacy of natural enemies, and the likelihood of resistance build-up. Ten geographic populations of C. agricola (six from Tasmania, one from the Australian Capital Territory, one from New South Wales and two from Victoria) were examined for genetic variation and gene flow using cellulose acetate allozyme electrophoresis. Six enzyme systems (PGI, PGD, PGM, IDH, HEX and MPI) were consistently polymorphic and scorable and were used to quantify estimated gene flow between populations. FST values and analysis of molecular variance indicated that gene flow was restricted between populations. Chrysophtharta agricola exhibited high levels of heterozygosity, probably because of high allelic diversity, and because all loci examined were polymorphic. The southern-most population was the most genetically different to other Tasmanian populations, and may also have been the most recently colonized. Limited gene flow implies that outbreaks of C. agricola should be spatially predictable and populations susceptible to control by natural enemies. Our results also imply that genetic resistance to chemical control may occur under frequent application of insecticide. However, testing population movement between plantations and native forest also needs to be conducted to assess gene flow between forest types.


2016 ◽  
Vol 64 (2) ◽  
pp. 763 ◽  
Author(s):  
Samuel Novais

Human pressure on natural habitats increases the importance of agroforests for biodiversity conservation. The objective of this study was to evaluate the role of traditional cacao agroforests, known as “cabrucas,” on the conservation of the herbivorous insect community in compared with that of monodominant rubber agroforests. The insects were sampled in three habitats in southeastern Bahia, Brazil: native forests, cabrucas and rubber agroforests. In each habitat, 18 plots of 10 m<sup>2 </sup>were established, and the structural measures were collected and herbivorous insects were sampled with a Malaise/window trap. The diversity of folivores decreased with the simplification of vegetation structure, but species composition was similar among habitats. In addition to a decrease in the availability of resources in monodominant rubber agroforests, the latex present in these systems limits the occurrence of species that cannot circumvent latex toxicity. The diversity of sap-sucking insects was similar among habitats, but species composition was similar only in the cabruca and native forest, and it was different in the rubber agroforest. We observed turnover and a higher frequency of individuals of the family Psyllidae in the rubber agroforest. The biology and behavior of psyllids and absence of natural enemies enable their diversity to increase when they are adapted to a new host. We observed a shift in the composition of xylophagous insects in the rubber agroforest compared with that of the other habitats. Moreover, this agroforest has low species richness but high individual abundance. Latex extraction is likely an important additional source of volatile compounds discharged into the environment, and it increases the attraction and recruitment of coleoborers to these sites. We conclude that cabrucas have an herbivorous insect community with a structure similar to the community found in native forests of the region, and they present a more interesting conservation strategy when compared with the rubber agroforests. We also emphasize the potential risk of local pest outbreaks in rubber agroforests for both the rubber trees and associated cacao tress.


2007 ◽  
Vol 50 (6) ◽  
pp. 1051-1060 ◽  
Author(s):  
Avacir Casanova Andrello ◽  
Carlos Roberto Appoloni ◽  
Virgílio Franco do Nascimento Filho

The aim of this work was to assess the soil erosion process in native forest by the 137Cs methodology. The mass balance model was applied to assess the rates of soil loss in three native forests around of Londrina city, Paraná, Brazil. 137Cs distribution depth was of exponential type for the three forests and 137Cs inventory was 241 Bq m-2 for Mata 1, 338 Bq m-2 for Mata 2 and 325 Bq m-2 for Mata UEL. The soil loss value calculated for three native forests was: 6,684 kg ha-1 yr-1 for Mata 1, 1,788 kg ha-1 yr-1 for Mata 2 and 4,524 kg ha-1 yr-1 for Mata UEL.


Mycorrhiza ◽  
2020 ◽  
Vol 30 (6) ◽  
pp. 749-759
Author(s):  
Zerihun Belay ◽  
Mesele Negash ◽  
Janne Kaseva ◽  
Mauritz Vestberg ◽  
Helena Kahiluoto

Abstract The rapid conversion of native forests to farmland in Ethiopia, the cradle of biodiversity, threatens the diversity of the arbuscular mycorrhizal fungi (AMF) pivotal to plant nutrition and carbon sequestration. This study aimed to investigate the impact of this land-use change on the AMF species composition and diversity in southern Ethiopia. Soil samples were collected from nine plots in each of three land-use types: native forest, agroforestry, and khat monocropping. The plots of the three land-use types were located adjacent to each other for each of the nine replicates. Three 10 × 10m subplots per plot were sampled. AMF spores were extracted from the soil samples, spore densities were determined, and species composition and diversity were evaluated through morphological analysis. Both spore density and species richness were statistically significantly higher in the native forest than in the agroforestry plots with no clear difference to khat, whereas the true diversity (exponential of Shannon–Wiener diversity index) did not differ among the three land-use types due to high evenness among the species in agroforestry. In total, 37 AMF morphotypes belonging to 12 genera in Glomeromycota were found, dominated by members of the genera Acaulospora and Glomus. The highest isolation frequency index (78%) was recorded for Acaulospora koskei from native forest. Consequently, the agroforestry system did not appear to aid in preserving the AMF species richness of native forests relative to perennial monocropping, such as khat cultivation. In contrast, the native forest areas can serve as in situ genetic reserves of mycorrhizal symbionts adapted to the local vegetative, edaphic, and microbial conditions.


Forests ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 946 ◽  
Author(s):  
Kathleen A. McGinley ◽  
Guy C. Robertson ◽  
Kathleen S. Friday

Forests across the U.S. and U.S. affiliated islands of the Caribbean and Pacific constitute rich and dynamic social-ecological systems that, while heterogeneous in many ways, share certain characteristics and trends that underscore the utility of sustainability assessments that go beyond single jurisdictional efforts. This paper summarizes a recent effort to assess the sustainability of tropical island forests of and politically affiliated with the U.S. using the Montréal Process criteria and indicator framework (MP C&I), which address ecological, social, economic, and institutional dimensions of forests. Forests cover 45 percent of the total area and more than 50 percent of each island jurisdiction, except Hawaii (36 percent). Forest cover is generally stable over much of the area in terms of recent reference conditions. The history of human occupation and land alteration is a prominent determinant of current conditions throughout the islands, which exhibit relatively high rates of threatened species in comparison to mainland counterparts and particularly where endemism is high. The islands also harbor significant areas of new or novel assemblages of native and non-native forest species, predominately on abandoned agricultural lands cleared of native forests long ago, which have been shown to contribute to the restoration of these degraded lands and provide many other ecosystem services at levels as high as and in some cases higher than native forests. Although industrial-level commercial timber harvest is small to nonexistent on most islands, socioeconomic and cultural linkages to forests are extensive but difficult to quantify. Amassing a foundation of data sufficient to address the MP C&I was challenging, in part due to the heterogeneity of the islands, island geography, and limited reporting capacities. We document significant improvements in the availability of data important for sustainability assessments in the last decade or so, especially with the extension of the U.S. Department of Agriculture Forest Service Forest Inventory and Analysis program to the islands. Likewise, we find the MP C&I to be a useful tool for organizing and presenting information important for assessing forest sustainability. Nevertheless, considerable data gaps remain in the areas of biodiversity, forest functions and processes, and socioeconomic conditions of forests, which are critical elements to track across the islands, particularly in the context of climate change and ongoing anthropogenic pressures.


2005 ◽  
Vol 53 (1) ◽  
pp. 33 ◽  
Author(s):  
Emma K. Gras ◽  
Jennifer Read ◽  
Chantal T. Mach ◽  
Gordon D. Sanson ◽  
Fiona J. Clissold

Eucalyptus species often show marked differences in morphology and ecophysiology between adult and juvenile leaves. Given these differences, it was hypothesised that juvenile and adult leaves would present different levels of resources to a herbivore, and potentially different levels of putative anti-herbivore defences. This hypothesis was tested in some eucalypts growing in native forest in south-eastern Australia. There were no significant differences in levels of water, protein or carbohydrates (per unit dry weight) between mature adult and juvenile leaves. No difference was recorded in concentration of total phenolics between leaf forms, but more protein was precipitated (an estimate of tannin activity) in extracts from juvenile leaves. Cyanogenic glycosides were absent from mature leaves, but present in young leaves of both leaf forms in E. polyanthemos. No significant difference in concentration of any terpene was recorded between adult and juvenile leaves in E. nitens and E. regnans. Specific leaf area was lower in adult leaves, and fibre concentration was higher in adult leaves of some species, suggesting that resources in the adult leaf may be less accessible to a herbivore. However, there was no difference in leaf toughness between leaf forms, even though toughness per unit leaf thickness was higher in juvenile leaves. Hence, no major trends in resource concentration were apparent between the leaf forms, and of the defences investigated, only tannin activity varied significantly between the leaf forms.


Soil Research ◽  
2000 ◽  
Vol 38 (2) ◽  
pp. 435 ◽  
Author(s):  
M. C. L. Todd ◽  
M. A. Adams ◽  
P. F. Grierson

Mine site rehabilitation should aim to establish quickly and maintain the processes of nutrient cycling at rates comparable with, or approaching, those of native forests. Current management strategies for rehabilitating bauxite mines and other mine sites in Australia usually include planting fast-growing understorey species at high densities and applying fertiliser. We provide the first detailed study of nitrogen (N) availability and N transformations (mineralisation/immobilisation) in such rehabilitated mine sites. Mean concentrations of NO3– (0–5 cm) in a chronosequence (7, 13, 22, and 27 years old) of rehabilitated mine sites ranged from 0.5 to 1.3 kg/ha, and NH4+ from 4.0 to 9.5 kg/ha. In burnt and unburnt native jarrah (E. marginata Donn ex. Smith) forests adjacent to the mine site, mean NO3– concentrations in surface soil (0–5 cm) were 0.8 kg/ha (burnt) and 1.1 kg/ha (unburnt), and mean NH4+ concentrations were 6.8 kg/ha (burnt) and 7.8 kg/ha (unburnt). Concentration of NH4+ at 0–5 cm was strongly related to soil water content (R2 = 0.69, P < 0.05) in rehabilitation sites, but not at 5–10 cm depth. Rates of N mineralisation (0–5 cm) in rehabilitation sites ranged from 34 to 52 kg/ha.year, of the same order as rates in native forest soil. In all rehabilitation and native forest sites, rates of N mineralisation were significantly related to rates of N-uptake at both 0–5 and 5–10 cm depth (R2 > 0.63, P < 0.05). Soil C/N ratios (0–5 cm) in rehabilitation sites ranged from 22.4 to 38.8, and in native forests from 35.6 (burnt) to 40.3 (unburnt). Soil C/N ratios increased with depth in both rehabilitation and native forest sites (ranged from 31.2 to 51.6). Availability of water was the major determinant of nitrogen availability in this strongly Mediterranean climate.


Sociobiology ◽  
2018 ◽  
Vol 65 (2) ◽  
pp. 340 ◽  
Author(s):  
Tae Tanaami Fernandes ◽  
Débora Rodrigues Souza-Camapana ◽  
Rogério Rosa Silva ◽  
Maria Santina Castro Morini

Ants often colonize twigs in the leaf litter, but some species use this resource more frequently than others. We analyzed the composition of the community and the diameter of colonized twigs to test if any species had a size preference. Samples were collected in different vegetation habitats (urban parks, eucalyptus plantations and native forests). In each site, all twigs with an ant colony in six 16-m2 plots were collected and measured, and the ants occupying them were identified. For the analyses, we only included species recorded in 10 or more twigs; these species were considered “common inhabitants” of the twigs (approximately 19.7% of the fauna analyzed). Our results indicate that the community is richer and uses a larger number of twigs of different diameters in the native forest. In addition, some species colonized twigs of similar sizes in different vegetation habitats, suggesting possible selection by ants.   


2021 ◽  
Author(s):  
◽  
Leo Mercer

<p>This research explores landowner preferences for various land use options suitable for Māori land in Te Tairāwhiti, on the East Coast of the North Island of Aotearoa-New Zealand (henceforth Aotearoa). A particular emphasis is placed on the applicability and feasibility of native forest carbon farming within the New Zealand Emissions Trading Scheme (NZ ETS) and opportunities, barriers and risks associated with this land use. Alongside this focus, is a wider investigation into the socio-cultural, environmental and economic co-benefits Māori landowners associate with traditional and emerging land uses in Te Tairāwhiti. This study uses a transformative research approach that is rooted in the spirit of kaupapa Māori research.  Some 90 percent of Māori land in Te Tairāwhiti has severe limitations which restrict land use options to plantation forestry or pastoral farming for most landowners. A response to these limitations, and a land development option favoured by government agencies, and the academy, is for ‘unproductive’ Māori land to be retired into permanent native forest carbon sinks – a solution frequently proffered as a positive means to address national climate change commitments and local environmental and socioeconomic issues. Whilst these objectives, and the land use preferences of Māori seemingly converge, the wider history of land loss and alienation influences perceptions of fairness and equity for Māori landowners who may feel pressured by the lack of attractive land use options to establish permanent carbon sinks, which can effectively constrain land use options for future generations.  Through case study analysis of a Māori sheep and beef farming incorporation participating in the NZ ETS, this study suggests an economic case for carbon farming in Te Tairāwhiti. However, institutional and socio-cultural barriers hinder the participation of Māori landowners in the NZ ETS. The second focus of this thesis has been an investigation into how native forest carbon farming is viewed when compared to other novel and existing land uses suitable for Māori land in the Waiapu catchment (a highly erodible catchment in Te Tairāwhiti). Interviews with key informants were employed to curate a set of land use options for Māori landowners to appraise, using multi-criteria analysis, at two wānanga. Four land use models were created for appraisal by 16 Māori landowner participants. The strength of association between a co-benefit and a land use was collectively deliberated upon in each of these models, and ratings were assigned to reflect this association. These ratings have aided in assessing the wider value of land uses for Māori in the region.   The results from this research indicate an overwhelming preference for native forests when compared to other suitable land uses. Native forests are most closely associated with environmental co-benefits (erosion control, water quality, biodiversity and withstanding and limiting climate change) and social and cultural co-benefits (skills development, employment, reconnecting with the land, and self-determination/autonomy). The strong performance of native forestry stands in stark contrast with other land uses under consideration such as exotic forestry (Pinus radiata within the study scenario) and sheep and beef farming which occupy the majority of ‘productive’ land in Te Tairāwhiti. Exotic forestry and sheep and beef farming are associated with few benefits beyond employment and skills development. There is also a clear perception in the quantitative and qualitative data that these uses disconnect Māori landowners from their land and reduce the ability of communities to be self-reliant.   Interestingly, other novel land uses under consideration such as perennial horticulture (including blueberries, macadamia nuts and apples), medicinal cannabis and hemp, and hunting and tourism were also valued more than exotic forestry and sheep and beef farming. These results indicate that existing land uses, sometimes implemented without express input from local communities, are now the least preferred land uses. In addition, novel and untested land uses such as medicinal cannabis and hemp, which do not exist at any scale in the region, are preferred over existing uses - even when there is scant evidence of success at any scale.   These results push back at the prevailing Pākehā dominated orthodoxy, which has existed from the early days of colonisation and holds that monoculture land uses, for profit above all else, are best suited to the land and the people. It is clear, from this study, that Māori landowners wish to move back to a vibrant multi-faceted land use regime – exemplified by diversity over homogeneity – that characterised the pre-colonisation Māori economy. This research accordingly introduces and explores a value articulating process that increases understanding of the aspirations and values of Māori landowners, and can assist Māori in progressing their land use futures.</p>


2021 ◽  
Author(s):  
◽  
Leo Mercer

<p>This research explores landowner preferences for various land use options suitable for Māori land in Te Tairāwhiti, on the East Coast of the North Island of Aotearoa-New Zealand (henceforth Aotearoa). A particular emphasis is placed on the applicability and feasibility of native forest carbon farming within the New Zealand Emissions Trading Scheme (NZ ETS) and opportunities, barriers and risks associated with this land use. Alongside this focus, is a wider investigation into the socio-cultural, environmental and economic co-benefits Māori landowners associate with traditional and emerging land uses in Te Tairāwhiti. This study uses a transformative research approach that is rooted in the spirit of kaupapa Māori research.  Some 90 percent of Māori land in Te Tairāwhiti has severe limitations which restrict land use options to plantation forestry or pastoral farming for most landowners. A response to these limitations, and a land development option favoured by government agencies, and the academy, is for ‘unproductive’ Māori land to be retired into permanent native forest carbon sinks – a solution frequently proffered as a positive means to address national climate change commitments and local environmental and socioeconomic issues. Whilst these objectives, and the land use preferences of Māori seemingly converge, the wider history of land loss and alienation influences perceptions of fairness and equity for Māori landowners who may feel pressured by the lack of attractive land use options to establish permanent carbon sinks, which can effectively constrain land use options for future generations.  Through case study analysis of a Māori sheep and beef farming incorporation participating in the NZ ETS, this study suggests an economic case for carbon farming in Te Tairāwhiti. However, institutional and socio-cultural barriers hinder the participation of Māori landowners in the NZ ETS. The second focus of this thesis has been an investigation into how native forest carbon farming is viewed when compared to other novel and existing land uses suitable for Māori land in the Waiapu catchment (a highly erodible catchment in Te Tairāwhiti). Interviews with key informants were employed to curate a set of land use options for Māori landowners to appraise, using multi-criteria analysis, at two wānanga. Four land use models were created for appraisal by 16 Māori landowner participants. The strength of association between a co-benefit and a land use was collectively deliberated upon in each of these models, and ratings were assigned to reflect this association. These ratings have aided in assessing the wider value of land uses for Māori in the region.   The results from this research indicate an overwhelming preference for native forests when compared to other suitable land uses. Native forests are most closely associated with environmental co-benefits (erosion control, water quality, biodiversity and withstanding and limiting climate change) and social and cultural co-benefits (skills development, employment, reconnecting with the land, and self-determination/autonomy). The strong performance of native forestry stands in stark contrast with other land uses under consideration such as exotic forestry (Pinus radiata within the study scenario) and sheep and beef farming which occupy the majority of ‘productive’ land in Te Tairāwhiti. Exotic forestry and sheep and beef farming are associated with few benefits beyond employment and skills development. There is also a clear perception in the quantitative and qualitative data that these uses disconnect Māori landowners from their land and reduce the ability of communities to be self-reliant.   Interestingly, other novel land uses under consideration such as perennial horticulture (including blueberries, macadamia nuts and apples), medicinal cannabis and hemp, and hunting and tourism were also valued more than exotic forestry and sheep and beef farming. These results indicate that existing land uses, sometimes implemented without express input from local communities, are now the least preferred land uses. In addition, novel and untested land uses such as medicinal cannabis and hemp, which do not exist at any scale in the region, are preferred over existing uses - even when there is scant evidence of success at any scale.   These results push back at the prevailing Pākehā dominated orthodoxy, which has existed from the early days of colonisation and holds that monoculture land uses, for profit above all else, are best suited to the land and the people. It is clear, from this study, that Māori landowners wish to move back to a vibrant multi-faceted land use regime – exemplified by diversity over homogeneity – that characterised the pre-colonisation Māori economy. This research accordingly introduces and explores a value articulating process that increases understanding of the aspirations and values of Māori landowners, and can assist Māori in progressing their land use futures.</p>


Sign in / Sign up

Export Citation Format

Share Document