scholarly journals Exotic urban trees conserve similar natural enemy communities to native congeners but have fewer pests

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6531 ◽  
Author(s):  
Steven D. Frank ◽  
Kristi M. Backe ◽  
Casey McDaniel ◽  
Matthew Green ◽  
Sarah Widney ◽  
...  

Urban trees serve a critical conservation function by supporting arthropod and vertebrate communities but are often subject to arthropod pest infestations. Native trees are thought to support richer arthropod communities than exotic trees but may also be more susceptible to herbivorous pests. Exotic trees may be less susceptible to herbivores but provide less conservation value as a consequence. We tested the hypotheses that native species in Acer and Quercus would have more herbivorous pests than exotic congeners and different communities of arthropod natural enemies. The density of scale insects, common urban tree pests, was greatest on a native Acer and a native Quercus than exotic congeners in both years of our research (2012 and 2016) and sometimes reached damaging levels. However, differences in predator and parasitoid abundance, diversity, and communities were not consistent between native and exotic species in either genus and were generally similar. For example, in 2012 neither predator nor parasitoid abundance differed among native and exotic Acer congeners but in 2016 a native species, A. saccharum, had the least of both groups. A native, Q. phellos, had significantly more predators and parasitoids in 2012 than its native and exotic congeners but no differences in 2016. Parasitoid communities were significantly different among Acer species and Quercus species due in each case to greater abundance of a single family on one native tree species. These native and exotic tree species could help conserve arthropod natural enemies and achieve pest management goals.

2008 ◽  
pp. 29-39 ◽  
Author(s):  
Cheryl Batistel ◽  
Victor Asio

The study evaluated the effects of incorporation and subsequent decomposition of leaves of exotic tree species (Gmelina arborea, Swietenia macrophylla and Tectona grandis) and native tree species (Pterocarpus indicus, Dipterocarpus validus and Parashorea plicata) on the quality of forest soil. Forty-two pots containing an acidic and clayey forest soil and added with fresh leaves of the different tree species were setup in an open area in Mt. Pangasugan. Retrieval of the first three pots for each treatment was done after two months and the remaining three pots, five months later. Soil samples were collected from each pot and were analyzed for soil respiration rate, pH, OM, total N and available P. Findings showed that in general the exotic tree species did not change the soil pH while the native species appeared to decrease it. Regardless of tree species, leaf decomposition significantly increased available soil phosphorus. The leaves of the exotic tree species decomposed faster than those of the native tree species.


2017 ◽  
Vol 47 (4) ◽  
pp. 311-320 ◽  
Author(s):  
Francisco Pinheiro da SILVA ◽  
Rodrigo Ferreira FADINI

ABSTRACT One of the problems affecting the quality of urban trees is their infestation by mistletoes (aerial hemiparasite plants of the order Santalales). Identification of the main types of trees infested, and of the causes of infestation patterns, can help infestation control and the planning of efficient planting regimes. In this sense, the aim of this study was to evaluate the patterns of hemiparasite infestation in trees in an Amazonian urban environment. We aimed to answer (1) which species of mistletoes occur on urban trees in the city of Santarém, in the Brazilian Amazon; (2) what is the proportion and intensity of infestation on infected trees; and (3) if differences in infestation rates among tree species can be explained by mistletoe-tree compatibility. We assessed mistletoe incidence and intensity of infestation on trees in the main avenues of the city. To evaluate the role of mistletoe-tree compatibility in the observed parasitism patterns, we carried out a seed inoculation experiment with seeds of the most abundant mistletoe, Passovia theloneura. Seeds were planted on three tree species (Andira inermis, Handroanthus serratifolius, and Mangifera indica). The overall infestation rate was 19.3%, with exotic tree species more infested than natives. The experiment showed that incompatibility between P. theloneura and the native H. serratifolius is primarily responsible for the observed non-infestation. Mistletoes germinated on A. inermis grew better than those on M. indica, contrary to the infestation prevalence found in the field, suggesting that patterns of infestation are also influenced by seed deposition processes.


2020 ◽  
Author(s):  
M. Arasumani ◽  
Milind Bunyan ◽  
V. V. Robin

ABSTRACTTropical montane grasslands (TMG) support biodiverse and endemic taxa and provide vital ecosystems services to downstream communities. Yet invasive alien tree species across the world have threatened tropical grasslands and grassland endemic species. In India, TMG in the Shola Sky Islands of the Western Ghats have been reduced due to exotic tree invasions (acacias, pines, and eucalyptus species). The loss of grassland habitat has, in turn, reduced the range sizes of species endemic to grasslands (plants, birds, amphibians, and mammals), driving some populations to local extinction. Grassland conversion to exotic trees has also reduced the annual runoff in the Western Ghats. Conserving existing grassland and restoring invaded habitat is critical to reverse these losses. This research focused on identifying grassland restoration sites using satellite images with a high spatial resolution (RapidEye). We used an object-oriented Random Forest classification to map the area for grassland restoration. We have identified an area of 254 sq. km. as suitable for grassland restoration and an area of 362 sq. km. for grassland conservation and prevention from invasion by exotic tree species. For restoration, we recommend a cautious removal of young and isolated exotic trees at the invasion front and restoring grasslands, instead of removing dense stands of mature exotic trees. We find that areas with low fire frequency areas tend to be invaded, but areas invaded by exotic trees tend to burn hotter which may be harmful to grassland species and ecosystems. We assume that removing exotic tree species in the identified restoration sites and restoring the grassland will be helpful in recovering lost habitat and ensuring the viability of populations of indigenous and endemic species and increasing streamflow.


Author(s):  
Leeladarshini Sujeeun ◽  
Sean C. Thomas

Many tropical invasive species have allelopathic effects that contribute to their success in native plant communities. Pyrolyzed biomass (“biochar”) can sorb toxic compounds, including allelochemicals produced by invasive plants, potentially reducing their inhibitory effects on native species. Strawberry guava (Psidium cattleianum) is among the most important allelopathic invasive species in tropical islands and recognized as the most serious invasive species threat in the global biodiversity hotspot of Mauritius. We investigated the effects of additions of locally produced biochar on native tree species in a field experiment conducted in areas invaded by strawberry guava within Mauritius’ largest national park. Growth and survivorship of native tree species were monitored over 2 ½ years in plots subjected to four treatments: non-weeded, weeded, weeded + 25 t/ha biochar and weeded + 50 t/ha biochar. Native tree growth and survivorship were strongly suppressed by strawberry guava. Biochar treatments dramatically increased native tree performance, with more than a doubling in growth, and substantially increased native tree survivorship and species diversity, while suppressing strawberry guava regeneration, consistent with growth-promoting properties and sorption of allelochemicals. We conclude that biochars, including “sustainable biochars” produced from locally accessible biomass using low-tech pyrolysis systems, have considerable potential to counteract effects of allelopathic invaders and increase the capacity for native species regeneration in tropical island ecosystems.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Elisabeth Pötzelsberger ◽  
Martin M. Gossner ◽  
Ludwig Beenken ◽  
Anna Gazda ◽  
Michal Petr ◽  
...  

AbstractFor non-native tree species with an origin outside of Europe a detailed compilation of enemy species including the severity of their attack is lacking up to now. We collected information on native and non-native species attacking non-native trees, i.e. type, extent and time of first observation of damage for 23 important non-native trees in 27 European countries. Our database includes about 2300 synthesised attack records (synthesised per biotic threat, tree and country) from over 800 species. Insects (49%) and fungi (45%) are the main observed biotic threats, but also arachnids, bacteria including phytoplasmas, mammals, nematodes, plants and viruses have been recorded. This information will be valuable to identify patterns and drivers of attacks, and trees with a lower current health risk to be considered for planting. In addition, our database will provide a baseline to which future impacts on non-native tree species could be compared with and thus will allow to analyse temporal trends of impacts.


2021 ◽  
Vol 22 (11) ◽  
Author(s):  
Edgardo P. Lillo ◽  
ARCHIEBALD B. MALAKI ◽  
STEVE MICHAEL T. ALCAZAR ◽  
RAAMAH ROSALES ◽  
BERNARDO R. REDOBLADO ◽  
...  

Abstract. Lillo EP, Malaki AB, Alcazar SMT, Rosales R, Redoblado BR, Diaz JLB, Pantinople EM, Buot Jr. IE. 2021. Inventory of native and mother trees in Key Biodiversity Areas of Cebu Island, Philippines for species selection in local reforestation programs. Biodiversitas 22: 4740-4749. Forest restoration is the counterforce of deforestation and forest degradation. Yet, despite promoting natural recovery after forest harvest, afforestation and reforestation efforts, tropical forest ecosystems still experience a poor ratio of forest loss to forest gain. The study assessed the native tree species and potential mother trees in different Cebu Island Key Biodiversity Areas (KBAs) as well as their distribution and habitat preferences which can be used in local reforestation programs. A vegetation survey was conducted in three KBAs in Cebu Island, namely Nug-as forest, Mount Lantoy and Mount Capayas to inventory all native species. Assessment based on the phenotypic characteristics of adult trees was also conducted for indicating mother trees. This study in Cebu Island KBAs recorded a total of 292 species, categorized into 125 families and 203 genera, which can be classified into native trees (210), vines and lianas (18), shrub (37), and herbs (27). Out of the 292 species, 214 were recorded in Nug-as forest, 172 in Mount Lantoy, and 145 in Mount Capayas. Of the 210 native tree species, Nug-as forest had 145 species, Mount Lantoy 131 species, and Mount Capayas 109 species. A total of 241 mother trees were identified in the three KBAs, corresponding to 77 species in which Nug-as forest had 143 trees correspond to 52 species, Mount Lantoy had 68 trees correspond to 29 species, and Mount Capayas had 31 trees correspond to 6 species. Such native tree species are recommended for reforestation programs as planting materials that could reduce the risks of failure due to its high adaptability to the environment.


2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Inda Mihu ◽  
Dipankar Borah ◽  
Sumpam Tangjang

Increasing human population and various developmental activities in the Indian state of Arunachal Pradesh, which lies in one of the most bio-diverse regions of the world, has caused large-scale deforestation, pushing a large number of native tree species to the serious verge of elimination from their native forest. In such tribal-dominated landscapes around the world, myriads of studies have emphasized the potential of homegardens as a site for local biodiversity conservation as they are known to have a huge Indigenous Knowledge System (IKS) on the use of diverse native floras. The present study was, therefore, undertaken to investigate if the native communities of the Mishmi tribe conserved native indigenous tree species in their homegardens and if they are grown then what is the future of these tree species? It was hypothesized that harbouring greater indigenous knowledge implies greater domestication of tree species in their homegardens. Altogether, 103 species of trees were recorded from 243 homegardens in the present study. Although the native species constituted more than half of the species diversity, they, however, greatly lagged in all other aspects of the study such as population share, frequency distribution and regeneration potential. Native tree species constituted just 37% of the total tree population. Only two species, Bauhinia variegata L. and Alnus nepalensis D. Don, made up the major bulk of the native population. In terms of frequency distribution, only a handful of native species maintained a decent presence in the homegardens. Most of the native species grew naturally in unmanaged homegardens. The regeneration potential of all native species was very poor, including B. variegata. The study demonstrates that out of the 76 native species recorded from the region, only 7 species can rightfully be regarded as being domesticated by virtue of IKS of the Mishmi community. Our study concludes that the native species do exist in large number in homegardens of the rural tribal areas, but most of the native wild species exist in the rural homegardens not because they are planted/preferred but because they just happen to randomly grow there since most of the homegardens of tribal household are unmanaged or poorly managed, thereby giving way to wild species to germinate, at least until the owner decides to weed them out.


Forests ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 885
Author(s):  
Rustum Aguilos ◽  
Conrado Marquez ◽  
Henry Adornado ◽  
Maricar Aguilos

Selection of native tree species for commercial purposes is a continuing challenge and an opportunity in tropical silviculture. Because of this, we explored domesticating 33 native species in the Philippines that were tested for survival rate, total height, and diameter-at-ground-level (dgl) increments. The first five years (2014–2018) of assessment showed that 13 species (40%) of the 33 native species reached a survival rate of more than 80%. Grouped as ‘slow’-, ‘medium’- and ‘fast’-growing field trial species, a 709 cm average total height at five years was attained by the fast-growing cluster where Bagalunga (Melia dubia L.) and Kupang (Parkia javanica (D.C.) Merr.) were among the fastest-growing species. Slow-growing trees like Tindalo (Afzelia rhomboidei (Blanco)) and Kamagong (Diospyros blancoi (Willd)) were among the slowest-growing with an average height of 193.8 cm. Dipterocarps like Yakal (Shorea stylosa (Foxw.)), Tanguile (Shorea polysperma (Blanco)) and Mayapis (Shorea squamata (Blanco) Merr.) had the lowest diameter at ground level (dgl) increments (average 25.9 mm) while diametric expansion of fast-growing species spanned up to 93.5 mm. Overall, height and dgl increments were almost five times the original measurement five years after planting. A sudden surge in the rate of change in total height (83%) and dgl (72%) occurred a year after planting, yet a sudden decline occurred in the fifth year with only 21% for height and 23% for diameter growth suggesting the first 3–4 years as the crucial stage in seedling development. Survival rate is better correlated with the changes in dgl increment (R2 = 0.19, p < 0.05) than the height growth (R2 = 0.12, p < 0.05). Increasing rainfall and optimum air temperature significantly correlated with height and diameter growth while any increase in recorded wind speed slightly reduced the growth of the species. Our findings are initial steps towards developing appropriate silvicultural and management interventions when planning for the massive plantation development of domesticated Philippine native trees in the future.


2021 ◽  
Author(s):  
Muhammad Umair Umair Shafique ◽  
Adnan Younis ◽  
Muhammad Asif ◽  
Mansoor Hameed

Abstract This present study mainly focuses on the tree distribution and diversity of some selected roadsides in Faisalabad, a major city in Punjab, Pakistan. A total census of the tree population on selected roads was carried out and then studied for various parameters. Shannon–Wiener index, Reciprocal of Simpson’s diversity index, and Shannon Evenness were among the different species diversity indices which were studied. Observational results showed that the selected roads in the city hold low tree diversity, with nearly 2858 trees of 34 species, 30 genera, and 15 families. Mainly exotic tree species dominated the plantation of selected roadsides. The topmost three species contributing approximately 60% of the tree population are Conocarpus erectus, Eucalyptus crebra, and Terminalia mantaly. Despite the dominance of exotic tree species, many native tree species are also growing along selected roadsides. Since, Faisalabad has been reported as one of the most polluted cities in the world due to high suspended particulate matter, appropriate efforts are needed to improve the plantation pattern and also to enhance the canopy of the trees in the city to minimize the problem of air pollution.


2021 ◽  
Author(s):  
Muhammad Afzal ◽  
Khalid Zamir Rasib

Abstract Termite infestation is one of the fundamental problems associated with the loss of urban trees and ecological services. However, no such study has been performed in Pakistan to investigate the termite occurrence and assess such damages to urban trees caused by termites. For Lahore, research and comparable data on urban tree damages are rare or missing. This study surveyed six different microhabitats, including Bagh-e-Jinnah, Canal vegetation, Model Town Park, Jallo forestry, Race-course Park, and F.C. College vegetation employing three belt transects (100×5 m) method. We geo-referenced termite infested trees to investigate the termite occurrence on living and dead standing trees, termite diversity and assess the tree damage by termites' attack. We recorded four termite species (Odontotermes obesus, Coptotermes heimi, Heterotermes indicola, and Microtermes obesi) representing two families (Rhinotermitidae and Termitidae). However, the diversity indices result revealed that O. obesus (higher termite) and C. heimi (lower termite) were dominant and key species with 46.60 and 36% of occurrence among observed trees, respectively. Kernel density function indicated that the Lahore Canal and Bagh-e-Jinnah plantation shared all four termites' infestation evenly compared to other study sites. We observed the maximum number of damaged trees by termites in canal plantations with the most damaged exotic tree species Populus euramericana along the canal green belt.Additionally, we observed significant (P < 0.05) termite-tree interactions with exotic, living, and dead standing tree species and found termite colony size positively (R = 0.985) correlated with the tree trunk diameter up to breast height DBH. The average population of termites per unit volume of deadwood log was (0.39/cm3) within all plantations-sites. In conclusion, this study provides simple, reckless, and inexpensive knowledge about the assessment of termite damage of trees, which may give a better idea in making decisions on tree selection and management in urban ecosystems.


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