scholarly journals Climate and habitat loss interactively restructure trait composition and covariance across a human-modified landscape

Author(s):  
Meghna Krishnadas

Species traits influence their response to environmental conditions and the match between phenotypes and environment mediates spatial changes in species composition. These trait-environment linkages can be disrupted in human-modified landscapes. Human land-use creates habitat fragments where dispersal limitation or edge effects can exclude species that may otherwise suit a given macro-scale environment. Furthermore, stressful micro-environments in fragments may limit viable trait combinations resulting in stronger trait covariance compared to contiguous forest, especially in harsher macroenvironments. In a wet tropical forest landscape in the Western Ghats Biodiversity Hotspot of peninsular India, I compared fragments with adjacent contiguous forest for signatures of trait-mediated assembly of tree communities along macroenvironmental gradients. Using four key plant traits—seed size, specific leaf area (SLA), wood density, and maximum height—I evaluated changes in trait-mediated abundances and trait covariance across environmental gradients. Trait-mediated abundances primarily changed along the elevation gradient in contiguous forest, smaller-seeded, shorter, thinner-leaved species increased at higher elevations. In fragments, higher SLA species increased in more seasonal climate and decreased with higher precipitation, and larger seeds decreased at warmer sites. However, traits only weakly predicted abundances and only contiguous forests experienced significant compositional change via traits, driven by trait syndromes varying along a composite environmental gradient defined by elevation, water deficit, and soil C:N ratio. Covariance of seed size and maximum height along gradients of precipitation and temperature revealed divergent constraints on viable phenotypes in fragments and contiguous forest. Notably, local biotic conditions (functional diversity) had stronger effects than environment in explaining trait covariance. Overall, the results imply that trait syndromes and trait covariance, rather than single traits, determine the phenotypes best suited to different macroenvironmental conditions and should inform management or restoration goals in fragments.

2008 ◽  
Vol 5 (4) ◽  
pp. 3593-3621 ◽  
Author(s):  
T. R. Baker ◽  
O. L. Phillips ◽  
W. F. Laurance ◽  
N. C. A. Pitman ◽  
S. Almeida ◽  
...  

Abstract. Understanding the relationships between plant traits and ecosystem properties at large spatial scales is important for predicting how compositional change will affect carbon cycling in tropical forests. Here, we examine the relationships between species wood density, maximum height and wood production for 60 Amazonian forest plots. Firstly, we examine how community-level species traits vary across Amazonia. Average species maximum height and wood density are low in western, compared to eastern, Amazonia and are negatively correlated with aboveground wood productivity and soil fertility. Secondly, we compare biomass growth rates across functional groups defined on the basis of these two traits. In similar size classes, biomass growth rates vary little between trees that differ in wood density and maximum height. However, biomass growth rates are generally higher in western Amazonia across all functional groups. Thirdly, we ask whether the data on the abundance and average biomass growth rates of different functional groups is sufficient to predict the observed, regional-scale pattern of wood productivity. We find that the lower rate of wood production in eastern compared to western Amazonia cannot be estimated on the basis of this information. Overall, these results suggest that the correlations between community-level trait values and wood productivity in Amazonian forests are not causative: direct environmental control of biomass growth rates appears to be the most important driver of wood production at regional scales. This result contrasts with findings for forest biomass where variation in wood density, associated with variation in species composition, is an important driver of regional-scale patterns. Tropical forest wood productivity may therefore be less sensitive than biomass to compositional change that alters community-level averages of these plant traits.


2010 ◽  
Vol 98 (3) ◽  
pp. 697-704 ◽  
Author(s):  
Johannes Metz ◽  
Pierre Liancourt ◽  
Jaime Kigel ◽  
Danny Harel ◽  
Marcelo Sternberg ◽  
...  

Zootaxa ◽  
2019 ◽  
Vol 4609 (1) ◽  
pp. 68
Author(s):  
AKSHAY KHANDEKAR ◽  
NIKHIL GAITONDE ◽  
ISHAN AGARWAL

We present a preliminary ND2 phylogeny of South Asian Cnemaspis, recovering a number of deeply divergent clades within Indian Cnemaspis, endemic to the southern and northern Western Ghats besides the Mysore Plateau and hills of Tamil Nadu. There are a number of unnamed lineages that are >5% divergent on ND2 across the phylogeny, including three from the gracilis clade on an elevation gradient (800–1400 m asl.) around Yercaud in the Shevaroy massif, Salem district, Tamil Nadu. We describe two of these as new species— Cnemaspis shevaroyensis sp. nov. and Cnemaspis thackerayi sp. nov. are both allied to Cnemaspis gracilis and can be diagnosed from all other Indian Cnemaspis by the absence of spine-like scales on flank, heterogeneous dorsal pholidosis, presence of femoral and precloacal pores, tail with enlarged, strongly keeled, conical tubercles forming whorls, a median row of enlarged and smooth sub-caudals. They differ from C. gracilis and each other in body size, the number of tubercles around midbody, the number of tubercles in paravertebral rows, the number of femoral and precloacal pores, the number of poreless scales in-between precloacal pores and between femoral and precloacal pores, and subtle colour pattern differences; besides uncorrected mitochondrial sequence divergence (7.9–16.6 %). We also provide a description of Cnemaspis yercaudensis from its type locality and an additional locality. The discovery of two endemic species and a third unnamed divergent lineage from an isolated massif in peninsular India outside the Western Ghats indicate that many other such understudied hill ranges may harbour high endemic biodiversity. 


Forests ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 1089
Author(s):  
Lan Jiang ◽  
Zhongsheng He ◽  
Jinfu Liu ◽  
Cong Xing ◽  
Xinguang Gu ◽  
...  

Researches focused on soil carbon (C), nitrogen (N), and phosphorus (P) content and the stoichiometry characteristics along elevation gradients are important for effective management of forest ecosystems. Taking the soil of different elevations from 900 to 1700 m on Daiyun Mountain as the object, the elevation distribution of total C, N, and P in soil and their stoichiometry characteristics were studied. Also, the driving factors resulting in the spatial heterogeneity of soil stoichiometry are presented. The results show the following: (1) The average soil C and N content was 53.03 g·kg−1 and 3.82 g·kg−1, respectively. The content of C and N at high elevation was higher than that of at low elevation. Soil phosphorus fluctuated with elevation. (2) With increasing elevation, soil C:N ratio increased initially to 17.40 at elevation between 900–1000 m, and then decreased to 12.02 at elevation 1600 m. The changing trends of C:P and N:P were similar, and they all fluctuated with elevation. (3) Elevation, soil bulk density, and soil temperature were the main factors influencing the variation of soil C, N, and C:N. Soil pH and slope position were the driving factors for soil P, C:P, and N:P. The soil is rich in C and N, and has less total phosphorus on Daiyun Mountain. Raising the level of phosphate fertilizer appropriately can help to improve soil fertility and promote plant growth as well. In light of this information, in the near future, it will be necessary to conduct separation management of C, N, and P with regular monitoring systems to maintain favorable conditions for soil.


2020 ◽  
Vol 295 (40) ◽  
pp. 13940-13955 ◽  
Author(s):  
Katrina J. Linden ◽  
Judy Callis

In a single vascular plant species, the ubiquitin system consists of thousands of different proteins involved in attaching ubiquitin to substrates, recognizing or processing ubiquitinated proteins, or constituting or regulating the 26S proteasome. The ubiquitin system affects plant health, reproduction, and responses to the environment, processes that impact important agronomic traits. Here we summarize three agronomic traits influenced by ubiquitination: induction of flowering, seed size, and pathogen responses. Specifically, we review how the ubiquitin system affects expression of genes or abundance of proteins important for determining when a plant flowers (focusing on FLOWERING LOCUS C, FRIGIDA, and CONSTANS), highlight some recent studies on how seed size is affected by the ubiquitin system, and discuss how the ubiquitin system affects proteins involved in pathogen or effector recognition with details of recent studies on FLAGELLIN SENSING 2 and SUPPRESSOR OF NPR CONSTITUTIVE 1, respectively, as examples. Finally, we discuss the effects of pathogen-derived proteins on plant host ubiquitin system proteins. Further understanding of the molecular basis of the above processes could identify possible genes for modification or selection for crop improvement.


2015 ◽  
Vol 32 (5) ◽  
pp. 368-383 ◽  
Author(s):  
James W. Dalling ◽  
Katherine Heineman ◽  
Grizelle González ◽  
Rebecca Ostertag

Abstract:Tropical montane forests (TMF) are associated with a widely observed suite of characteristics encompassing forest structure, plant traits and biogeochemistry. With respect to nutrient relations, montane forests are characterized by slow decomposition of organic matter, high investment in below-ground biomass and poor litter quality, relative to tropical lowland forests. However, within TMF there is considerable variation in substrate age, parent material, disturbance and species composition. Here we emphasize that many TMFs are likely to be co-limited by multiple nutrients, and that feedback among soil properties, species traits, microbial communities and environmental conditions drive forest productivity and soil carbon storage. To date, studies of the biogeochemistry of montane forests have been restricted to a few, mostly neotropical, sites and focused mainly on trees while ignoring mycorrhizas, epiphytes and microbial community structure. Incorporating the geographic, environmental and biotic variability in TMF will lead to a greater recognition of plant–soil feedbacks that are critical to understanding constraints on productivity, both under present conditions and under future climate, nitrogen-deposition and land-use scenarios.


2020 ◽  
Vol 44 (2) ◽  
pp. 129-136
Author(s):  
Ramazan Murtazaliev ◽  
Dzhalaludin Anatov ◽  
Jana Ekhvaia ◽  
Ziyarat Guseinova ◽  
Ketevan Batsatsashvili

Plant traits have been used to predict species and community responses to environmental gradients. We studied variation of leaf area (LA), specific leaf area (SLA), flowering shoot number and seed mass along an elevation gradient in the case of Trigonocaryum involucratum, a scree-growing plant endemic to the Caucasus ecoregion. The study had two major aims: (1) to compare the role of intra-population and inter-population variation of functional trait values; and (2) to ascertain dependence between elevation and trait values and their variation. We collected trait data in several populations in Dagestan (Russian Federation), where the species has about a 1000-m amplitude of elevational distribution. The intraspecific variability of trait values was assessed via standard statistical tools (one-way ANOVA and linear regression analysis). The trait values mostly have high inter-population variation (more than 90% for each of the trait values compared to intra-population variation of each trait), indicating adaptation of populations to site conditions. Much higher intra- vs. inter-population variation in SLA at subnival elevations indicates local micro-site diversity and may serve as a buffer against future stress related to climate change. All the trait values negatively but significantly correlate (weakly or moderately) with elevation. Negative correlation presumably shows a certain increase in the limiting effect of the elevation gradient associated with changes in temperature, soil nutrient availability and soil water content, as well as with high solar radiation. More evidence from a broader study of the species throughout its distribution range is needed for firmer conclusions about the intraspecific variability of T. involucratum.


2020 ◽  
Author(s):  
Nayara Mesquita Mota ◽  
Markus Gastauer ◽  
Juan Fernando Carrión ◽  
João Augusto Alves Meira-Neto

AbstractRoad networks cause disturbances that can alter the biodiversity and the functioning of the Caatinga ecosystems. We tested the hypotheses that (i) Caatinga vegetation near roads is less taxonomically, functionally and phylogenetically diverse, (ii) phylogenetically and functionally more clustered than vegetation further from roads, (iii) plant traits associated with herbivory deterrence are conserved within the phylogenetic lineages, and (iv) Caatinga vegetation near roads selects for disturbance-related traits. We sampled herbaceous and woody component of vegetation in four plots near roads and four plots further from roads to test these hypothesis. Sampled species were classified according to their resprouting capacity, nitrogen fixation, succulence/spines, urticancy/toxicity, lifeform, endozoochory, maximum height and maximum diameter, before we calculated the taxonomic, functional and phylogenetic diversity of plant communities. Species richness, taxonomic, functional and phylogenetic diversities were lower in plots close to the roads, confirming roads as sources of disturbances. The phylogenetic structure of the Caatinga vegetation near roads was clustered, indicating environmental filtering by herbivory as the main pervasive disturbance in Caatinga ecosystems, since traits related to herbivory deterrence were conserved within phylogenetic lineages and were filtered in near roads. Thus, roads should be considered degradation conduits causing taxonomic, phylogenetic and functional impoverishment of Caatinga vegetation.


2018 ◽  
Author(s):  
Rafael D’Andrea ◽  
Maria Riolo ◽  
Annette Ostling

AbstractPatterns of trait distribution among competing species can potentially reveal the processes that allow them to coexist. It has been recently proposed that competition may drive the spontaneous emergence of niches comprising clusters of similar species, in contrast with the dominant paradigm of greater-than-chance species differences. However, current clustering theory relies largely on heuristic rather than mechanistic models. Furthermore, studies of models incorporating demographic stochasticity and immigration, two key players in community assembly, did not observe clusters. Here we demonstrate clustering under partitioning of resources, partitioning of environmental gradients, and a competition-colonization tradeoff. We show that clusters are robust to demographic stochasticity, and can persist under immigration. While immigration may sustain clusters that are otherwise transient, too much dilutes the pattern. In order to detect and quantify clusters in nature, we introduce and validate metrics which have no free parameters nor require arbitrary trait binning, and weigh species by their abundances rather than relying on a presence-absence count. By generalizing beyond the circumstances where clusters have been observed, our study contributes to establishing them as an update to classical trait patterning theory.Author SummarySpecies traits determine how they compete with each other. As such, patterns in the distributions of traits in a community of competing species may reveal the processes responsible for coexistence. One central idea in theoretical ecology is that the strength of competition relates to similarity in species needs and strategies, and therefore if competition plays out at short timescales, coexisting species should be more different than expected by chance. However, recent theory suggests that competition may lead species to temporarily self-organize into groups with similar traits. Here we show that this clustering is a generic feature of competitive dynamics, which is robust to demographic stochasticity and can be indefinitely maintained by immigration. We show that clustering arises whether species coexist by partitioning resources, environmental preferences, or through tradeoffs in life-history strategies. We introduce and validate metrics that, given species traits and abundances, determine whether they are clustered, and if so, how many clusters occur. By showing the generality of self-organized species clusters and providing a tools for their detection, our study contributes to updating classical ideas about how competition shapes communities, and motivates searches for them in nature.


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